Patent No. 6506148 Nervous system manipulation by EM Fields from monitors
Patent No. 6506148
Nervous system manipulation by EM Fields from monitors (Loos, Jan 14, 2003)
Physiological effects have been observed in a human subject in response to stimulation of the skin with weak electromagnetic fields that are pulsed with certain frequencies near 1/2 Hz or 2.4 Hz, such as to excite a sensory resonance. Many computer monitors and TV tubes, when displaying pulsed images, emit pulsed electromagnetic fields of sufficient amplitudes to cause such excitation. It is therefore possible to manipulate the nervous system of a subject by pulsing images displayed on a nearby computer monitor or TV set. For the latter, the image pulsing may be imbedded in the program material, or it may be overlaid by modulating a video stream, either as an RF signal or as a video signal. The image displayed on a computer monitor may be pulsed effectively by a simple computer program. For certain monitors, pulsed electromagnetic fields capable of exciting sensory resonances in nearby subjects may be generated even as the displayed images are pulsed with subliminal intensity.
Notes:
BACKGROUND
OF THE INVENTION
The invention relates to the stimulation of the human nervous system by an electromagnetic
field applied externally to the body. A neurological effect of external electric
fields has been mentioned by Wiener (1958), in a discussion of the bunching
of brain waves through nonlinear interactions. The electric field was arranged
to provide "a direct electrical driving of the brain". Wiener describes the
field as set up by a 10 Hz alternating voltage of 400 V applied in a room between
ceiling and ground. Brennan (1992) describes in U.S. Pat. No. 5,169,380 an apparatus
for alleviating disruptions in circadian rythms of a mammal, in which an alternating
electric field is applied across the head of the subject by two electrodes placed
a short distance from the skin.
A device involving a field electrode as well as a contact electrode is the "Graham
Potentializer" mentioned by Hutchison (1991). This relaxation device uses motion,
light and sound as well as an alternating electric field applied mainly to the
head. The contact electrode is a metal bar in Ohmic contact with the bare feet
of the subject, and the field electrode is a hemispherical metal headpiece placed
several inches from the subject's head.
In these three electric stimulation methods the external electric field is applied
predominantly to the head, so that electric currents are induced in the brain
in the physical manner governed by electrodynamics. Such currents can be largely
avoided by applying the field not to the head, but rather to skin areas away
from the head. Certain cutaneous receptors may then be stimulated and they would
provide a signal input into the brain along the natural pathways of afferent
nerves. It has been found that, indeed, physiological effects can be induced
in this manner by very weak electric fields, if they are pulsed with a frequency
near 1/2 Hz. The observed effects include ptosis of the eyelids, relaxation,
drowziness, the feeling of pressure at a centered spot on the lower edge of
the brow, seeing moving patterns of dark purple and greenish yellow with the
eyes closed, a tonic smile, a tense feeling in the stomach, sudden loose stool,
and sexual excitement, depending on the precise frequency used, and the skin
area to which the field is applied. The sharp frequency dependence suggests
involvement of a resonance mechanism.
It has been found that the resonance can be excited not only by externally applied
pulsed electric fields, as discussed in U.S. Pat. Nos. 5,782,874, 5,899,922,
6,081,744, and 6,167,304, but also by pulsed magnetic fields, as described in
U.S. Pat. Nos. 5,935,054 and 6,238,333, by weak heat pulses applied to the skin,
as discussed in U.S. Pat. Nos. 5,800,481 and 6,091,994, and by subliminal acoustic
pulses, as described in U.S. Pat. No. 6,017,302. Since the resonance is excited
through sensory pathways, it is called a sensory resonance. In addition to the
resonance near 1/2 Hz, a sensory resonance has been found near 2.4 Hz. The latter
is characterized by the slowing of certain cortical processes, as discussed
in the '481, '922, '302, '744, '944, and '304 patents.
The excitation of sensory resonances through weak heat pulses applied to the
skin provides a clue about what is going on neurologically. Cutaneous temperature-sensing
receptors are known to fire spontaneously. These nerves spike somewhat randomly
around an average rate that depends on skin temperature. Weak heat pulses delivered
to the skin in periodic fashion will therefore cause a slight frequency modulation
(fm) in the spike patterns generated by the nerves. Since stimulation through
other sensory modalities results in similar physiological effects, it is believed
that frequency modulation of spontaneous afferent neural spiking patterns occurs
there as well.
It is instructive to apply this notion to the stimulation by weak electric field
pulses administered to the skin. The externally generated fields induce electric
current pulses in the underlying tissue, but the current density is much too
small for firing an otherwise quiescent nerve. However, in experiments with
adapting stretch receptors of the crayfish, Terzuolo and Bullock (1956) have
observed that very small electric fields can suffice for modulating the firing
of already active nerves. Such a modulation may occur in the electric field
stimulation under discussion.
Further understanding may be gained by considering the electric charges that
accumulate on the skin as a result of the induced tissue currents. Ignoring
thermodynamics, one would expect the accumulated polarization charges to be
confined strictly to the outer surface of the skin. But charge density is caused
by a slight excess in positive or negative ions, and thermal motion distributes
the ions through a thin layer. This implies that the externally applied electric
field actually penetrates a short distance into the tissue, instead of stopping
abruptly at the outer skin surface. In this manner a considerable fraction of
the applied field may be brought to bear on some cutaneous nerve endings, so
that a slight modulation of the type noted by Terzuolo and Bullock may indeed
occur.
The mentioned physiological effects are observed only when the strength of the
electric field on the skin lies in a certain range, called the effective intensity
window. There also is a bulk effect, in that weaker fields suffice when the
field is applied to a larger skin area. These effects are discussed in detail
in the '922 patent.
Since the spontaneous spiking of the nerves is rather random and the frequency
modulation induced by the pulsed field is very shallow, the signal to noise
ratio (S/N) for the fm signal contained in the spike trains along the afferent
nerves is so small as to make recovery of the fm signal from a single nerve
fiber impossibile. But application of the field over a large skin area causes
simultaneous stimulation of many cutaneous nerves, and the fm modulation is
then coherent from nerve to nerve. Therefore, if the afferent signals are somehow
summed in the brain, the fm modulations add while the spikes from different
nerves mix and interlace. In this manner the S/N can be increased by appropriate
neural processing. The matter is discussed in detail in the '874 patent. Another
increase in sensitivity is due to involving a resonance mechanism, wherein considerable
neural circuit oscillations can result from weak excitations.
An easily detectable physiological effect of an excited 1/2 Hz sensory resonance
is ptosis of the eyelids. As discussed in the '922 patent, the ptosis test involves
first closing the eyes about half way. Holding this eyelid position, the eyes
are rolled upward, while giving up voluntary control of the eyelids. The eyelid
position is then determined by the state of the autonomic nervous system. Furthermore,
the pressure excerted on the eyeballs by the partially closed eyelids increases
parasympathetic activity. The eyelid position thereby becomes somewhat labile,
as manifested by a slight flutter. The labile state is sensitive to very small
shifts in autonomic state. The ptosis influences the extent to which the pupil
is hooded by the eyelid, and thus how much light is admitted to the eye. Hence,
the depth of the ptosis is seen by the subject, and can be graded on a scale
from 0 to 10.
In the initial stages of the excitation of the 1/2 Hz sensory resonance, a downward
drift is detected in the ptosis frequency, defined as the stimulation frequency
for which maximum ptosis is obtained. This drift is believed to be caused by
changes in the chemical milieu of the resonating neural circuits. It is thought
that the resonance causes perturbations of chemical concentrations somewhere
in the brain, and that these perturbations spread by diffusion to nearby resonating
circuits. This effect, called "chemical detuning", can be so strong that ptosis
is lost altogether when the stimulation frequency is kept constant in the initial
stages of the excitation. Since the stimulation then falls somewhat out of tune,
the resonance decreases in amplitude and chemical detuning eventually diminishes.
This causes the ptosis frequency to shift back up, so that the stimulation is
more in tune and the ptosis can develop again. As a result, for fixed stimulation
frequencies in a certain range, the ptosis slowly cycles with a frequency of
several minutes. The matter is discussed in the '302 patent.
The stimulation frequencies at which specific physiological effects occur depend
somewhat on the autonomic nervous system state, and probably on the endocrine
state as well.
Weak magnetic fields that are pulsed with a sensory resonance frequency can
induce the same physiological effects as pulsed electric fields. Unlike the
latter however, the magnetic fields penetrate biological tissue with nearly
undiminished strength. Eddy currents in the tissue drive electric charges to
the skin, where the charge distributions are subject to thermal smearing in
much the same way as in electric field stimulation, so that the same physiological
effects develop. Details are discussed in the '054 patent.
SUMMARY
Computer monotors and TV monitors can be made to emit weak low-frequency electromagnetic
fields merely by pulsing the intensity of displayed images. Experiments have
shown that the 1/2 Hz sensory resonance can be excited in this manner in a subject
near the monitor. The 2.4 Hz sensory resonance can also be excited in this fashion.
Hence, a TV monitor or computer monitor can be used to manipulate the nervous
system of nearby people.
The implementations of the invention are adapted to the source of video stream
that drives the monitor, be it a computer program, a TV broadcast, a video tape
or a digital video disc (DVD).
For a computer monitor, the image pulses can be produced by a suitable computer
program. The pulse frequency may be controlled through keyboard input, so that
the subject can tune to an individual sensory resonance frequency. The pulse
amplitude can be controlled as well in this manner. A program written in Visual
Basic(R) is particularly suitable for use on computers that run the Windows
95(R) or Windows 98(R) operating system. The structure of such a program is
described. Production of periodic pulses requires an accurate timing procedure.
Such a procedure is constructed from the GetTimeCount function available in
the Application Program Interface (API) of the Windows operating system, together
with an extrapolation procedure that improves the timing accuracy.
Pulse variability can be introduced through software, for the purpose of thwarting
habituation of the nervous system to the field stimulation, or when the precise
resonance frequency is not known. The variability may be a pseudo-random variation
within a narrow interval, or it can take the form of a frequency or amplitude
sweep in time. The pulse variability may be under control of the subject.
The program that causes a monitor to display a pulsing image may be run on a
remote computer that is connected to the user computer by a link; the latter
may partly belong to a network, which may be the Internet.
For a TV monitor, the image pulsing may be inherent in the video stream as it
flows from the video source, or else the stream may be modulated such as to
overlay the pulsing. In the first case, a live TV broadcast can be arranged
to have the feature imbedded simply by slightly pulsing the illumination of
the scene that is being broadcast. This method can of course also be used in
making movies and recording video tapes and DVDs.
Video tapes can be edited such as to overlay the pulsing by means of modulating
hardware. A simple modulator is discussed wherein the luminance signal of composite
video is pulsed without affecting the chroma signal. The same effect may be
introduced at the consumer end, by modulating the video stream that is produced
by the video source. A DVD can be edited through software, by introducing pulse-like
variations in the digital RGB signals. Image intensity pulses can be overlaid
onto the analog component video output of a DVD player by modulating the luminance
signal component. Before entering the TV set, a television signal can be modulated
such as to cause pulsing of the image intensity by means of a variable delay
line that is connected to a pulse generator.
Certain monitors can emit electromagnetic field pulses that excite a sensory
resonance in a nearby subject, through image pulses that are so weak as to be
subliminal. This is unfortunate since it opens a way for mischievous application
of the invention, whereby people are exposed unknowingly to manipulation of
their nervous systems for someone else's purposes. Such application would be
unethical and is of course not advocated. It is mentioned here in order to alert
the public to the possibility of covert abuse that may occur while being online,
or while watching TV, a video, or a DVD.
DETAILED
DESCRIPTION
Computer monitors and TV monitors emit electromagnetic fields. Part of the emission
occurs at the low frequencies at which displayed images are changing. For instance,
a rythmic pulsing of the intensity of an image causes electromagnetic field
emission at the pulse frequency, with a strength proportional to the pulse amplitude.
The field is briefly referred to as "screen emission". In discussing this effect,
any part or all what is displayed on the monitor screen is called an image.
A monitor of the cathode ray tube (CRT) type has three electron beams, one for
each of the basic colors red, green, and blue. The intensity of an image is
here defined as
where the integral extends over the image, and
jr, jg, and jb being the electric current densities in the red, green, and blue
electron beams at the surface area dA of the image on the screen. The current
densities are to be taken in the distributed electron beam model, where the
discreteness of pixels and the raster motion of the beams are ignored, and the
back of the monitor screen is thought to be irradiated by diffuse electron beams.
The beam current densities are then functions of the coordinates x and y over
the screen. The model is appropriate since we are interested in the electromagnetic
field emision caused by image pulsing with the very low frequencies of sensory
resonances, whereas the emissions with the much higher horizontal and vertical
sweep frequencies are of no concern. For a CRT the intensity of an image is
expressed in millamperes.
For a liquid crystal display (LCD), the current densities in the definition
of image intensity are to be replaced by driving voltages, multiplied by the
aperture ratio of the device. For an LCD, image intensities are thus expressed
in volts.
It will be shown that for a CRT or LCD screen emissions are caused by fluctuations
in image intensity. In composite video however, intensity as defined above is
not a primary signal feature, but luminance Y is. For any pixel one has
where R, G, and B are the intensities of the pixel respectively in red, green
and blue, normalized such as to range from 0 to 1. The definition (3) was provided
by the Commission Internationale de l'Eclairage (CIE), in order to account for
brightness differences at different colors, as perceived by the human visual
system. In composite video the hue of the pixel is determined by the chroma
signal or chrominance, which has the components R-Y and B-Y It follows that
pulsing pixel luminance while keeping the hue fixed is equivalent to pulsing
the pixel intensity, up to an amplitude factor. This fact will be relied upon
when modulating a video stream such as to overlay image intensity pulses.
It turns out that the screen emission has a multipole expansion wherein both
monopole and dipole contributions are proportional to the rate of change of
the intensity I of (1). The higher order multipole contributions are proportional
to the rate of change of moments of the current density j over the image, but
since these contributions fall off rapidly with distance, they are not of practical
importance in the present context. Pulsing the intensity of an image may involve
different pulse amplitudes, frequencies, or phases for different parts of the
image. Any or all of these features may be under subject control.
The question arises whether the screen emission can be strong enough to excite
sensory resonances in people located at normal viewing distances from the monitor.
This turns out to be the case, as shown by sensory resonance experiments and
independently by measuring the strength of the emitted electric field pulses
and comparing the results with the effective intensity window as explored in
earlier work.
One-half Hertz sensory resonance experiments have been conducted with the subject
positioned at least at normal viewing distance from a 15" computer monitor that
was driven by a computer program written in Visual Basic(R), version 6.0 (VB6).
The program produces a pulsed image with uniform luminance and hue over the
full screen, except for a few small control buttons and text boxes. In VB6,
screen pixel colors are determined by integers R, G, and B, that range from
0 to 255, and set the contributions to the pixel color made by the basic colors
red, green, and blue. For a CRT-type monitor, the pixel intensities for the
primary colors may depend on the RGB values in a nonlinear manner that will
be discussed. In the VB6 program the RGB values are modulated by small pulses
.DELTA.R, .DELTA.G, .DELTA.B, with a frequency that can be chosen by the subject
or is swept in a predetermined manner. In the sensory resonance experiments
mentioned above, the ratios .DELTA.R/R, .DELTA.G/G, and .DELTA.B/B were always
smaller than 0.02, so that the image pulses are quite weak. For certain frequencies
near 1/2 Hz, the subject experienced physiological effects that are known to
accompany the excitation of the 1/2 Hz sensory resonance as mentioned in the
Background Section. Moreover, the measured field pulse amplitudes fall within
the effective intensity window for the 1/2 Hz resonance, as explored in earlier
experiments and discussed in the '874, '744, '922, and '304 patents. Other experiments
have shown that the 2.4 Hz sensory resonance can be exited as well by screen
emissions from monitors that display pulsed images.
These results confirm that, indeed, the nervous system of a subject can be manipulated
through electromagnetic field pulses emitted by a nearby CRT or LCD monitor
which displays images with pulsed intensity.
The various implementations of the invention are adapted to the different sources
of video stream, such as video tape, DVD, a computer program, or a TV broadcast
through free space or cable. In all of these implementations, the subject is
exposed to the pulsed electromagnetic field that is generated by the monitor
as the result of image intensity pulsing. Certain cutaneous nerves of the subject
exhibit spontaneous spiking in patterns which, although rather random, contain
sensory information at least in the form of average frequency. Some of these
nerves have receptors that respond to the field stimulation by changing their
average spiking frequency, so that the spiking patterns of these nerves acquire
a frequency modulation, which is conveyed to the brain. The modulation can be
particularly effective if it has a frequency at or near a sensory resonance
frequency. Such frequencies are expected to lie in the range from 0.1 to 15
Hz.
An embodiment of the invention adapted to a VCR is shown in FIG. 1, where a
subject 4 is exposed to a pulsed electric field 3 and a pulsed magnetic field
39 that are emitted by a monitor 2, labeled "MON", as the result of pulsing
the intensity of the displayed image. The image is here generated by a video
casette recorder 1, labeled "VCR", and the pulsing of the image intensity is
obtained by modulating the composite video signal from the VCR output. This
is done by a video modulator 5, labeled "VM", which responds to the signal from
the pulse generator 6, labeled "GEN". The frequency and amplitude of the image
pulses can be adjusted with the frequency control 7 and amplitude control 8.
Frequency and amplitude adjustments can be made by the subject.
The circuit of the video modulator 5 of FIG. 1 is shown in FIG. 2, where the
video amplifiers 11 and 12 process the composite video signal that enters at
the input terminal 13. The level of the video signal is modulated slowly by
injecting a small bias current at the inverting input 17 of the first amplifier
11. This current is caused by voltage pulses supplied at the modulation input
16, and can be adjusted through the potentiometer 15. Since the noninverting
input of the amplifier is grounded, the inverting input 17 is kept essentially
at ground potential, so that the bias current is is not influenced by the video
signal. The inversion of the signal by the first amplifier 11 is undone by the
second amplifier 12. The gains of the amplifiers are chosen such as to give
a unity overall gain. A slowly varying current injected at the inverting input
17 causes a slow shift in the "pseudo-dc" level of the composite video signal,
here defined as the short-term average of the signal. Since the pseudo-dc level
of the chroma signal section determines the luminance, the latter is modulated
by the injected current pulses. The chroma signal is not affected by the slow
modulation of the pseudodc level, since that signal is determined by the amplitude
and phase with respect to the color carrier which is locked to the color burst.
The effect on the sync pulses and color bursts is of no consequence either if
the injected current pulses are very small, as they are in practice. The modulated
composite video signal, available at the output 14 in FIG. 2, will thus exhibit
a modulated luminance, whereas the chroma signal is unchanged. In the light
of the foregoing discussion about luminance and intensity, it follows that the
modulator of FIG. 2 causes a pulsing of the image intensity I. It remains to
give an example how the pulse signal at the modulation input 16 may be obtained.
FIG. 3 shows a pulse generator that is suitable for this purpose, wherein the
RC timer 21 (Intersil ICM7555) is hooked up for astable operation and produces
a square wave voltage with a frequency that is determined by capacitor 22 and
potentiometer 23. The timer 21 is powered by a battery 26, controlled by the
switch 27. The square wave voltage at output 25 drives the LED 24, which may
be used for monitoring of the pulse frequency, and also serves as power indicator.
The pulse output may be rounded in ways that are well known in the art. In the
setup of FIG. 1, the output of VCR 1 is connected to the video input 13 of FIG.
2, and the video output 14 is connected to the monitor 2 of FIG. 1.
In the preferred embodiment of the invention, the image intensity pulsing is
caused by a computer program. As shown in FIG. 4, monitor 2, labeled "MON",
is connected to computer 31 labeled "COMPUTER", which runs a program that produces
an image on the monitor and causes the image intensity to be pulsed. The subject
4 can provide input to the computer through the keyboard 32 that is connected
to the computer by the connection 33. This input may involve adjustments of
the frequency or the amplitude or the variability of the image intensity pulses.
In particular, the pulse frequency can be set to a sensory resonance frequency
of the subject for the purpose of exciting the resonance.
The structure of a computer program for pulsing image intensity is shown in
FIG. 6. The program may be written in Visual Basic(R) version 6.0 (VB6), which
involves the graphics interface familiar from the Windows(R) operating system.
The images appear as forms equipped with user controls such as command buttons
and scroll bars, together with data displays such as text boxes. A compiled
VB6 program is an executable file. When activated, the program declares variables
and functions to be called from a dynamic link library (DLL) that is attached
to the operating system; an initial form load is performed as well. The latter
comprises setting the screen color as specified by integers R, G, and B in the
range 0 to 255, as mentioned above. In FIG. 6, the initial setting of the screen
color is labeled as 50. Another action of the form load routine is the computation
51 of the sine function at eight equally spaced points, I=0 to 7, around the
unit circle. These values are needed when modulating the RGB numbers. Unfortunately,
the sine function is distorted by the rounding to integer RGB values that occurs
in the VB6 program. The image is chosen to fill as much of the screen area as
possible, and it has spatially uniform luminance and hue.
The form appearing on the monitor displays a command button for starting and
stopping the image pulsing, together with scroll bars 52 and 53 respectively
for adjustment of the pulse frequency F and the pulse amplitude A. These pulses
could be initiated by a system timer which is activated upon the elapse of a
preset time interval. However, timers in VB6 are too inaccurate for the purpose
of providing the eight RGB adjustment points in each pulse cycle. An improvement
can be obtained by using the GetTickCount function that is available in the
Application Program Interface (API) of Windows 95(R) and Windows 98(R). The
GetTickCount function returns the system time that has elapsed since starting
Windows, expressed in milliseconds. User activation of the start button 54 provides
a tick count TN through request 55 and sets the timer interval to TT miliseconds,
in step 56. TT was previously calculated in the frequency routine that is activated
by changing the frequency, denoted as step 52.
Since VB6 is an event-driven program, the flow chart for the program falls into
disjoint pieces. Upon setting the timer interval to TT in step 56, the timer
runs in the background while the program may execute subroutines such as adjustment
of pulse frequency or amplitude. Upon elapse of the timer interval TT, the timer
subroutine 57 starts execution with request 58 for a tick count, and in 59 an
upgrade is computed of the time TN for the next point at which the RGB values
are to be adjusted. In step 59 the timer is turned off, to be reactivated later
in step 67. Step 59 also resets the parameter CR which plays a role in the extrapolation
procedure 61 and the condition 60. For ease of understanding at this point,
it is best to pretend that the action of 61 is simply to get a tick count, and
to consider the loop controled by condition 60 while keeping CR equal to zero.
The loop would terminate when the tick count M reaches or exceeds the time TN
for the next phase point, at which time the program should adjust the image
intensity through steps 63-65. For now step 62 is to be ignored also, since
it has to do with the actual extrapolation procedure 61. The increments to the
screen colors R1, G1, and B1 at the new phase point are computed according to
the sine function, applied with the amplitude A that was set by the user in
step 53. The number I that labels the phase point is incremented by unity in
step 65, but if this results in I=8 the value is reset to zero in 66. Finally,
the timer is reactivated in step 67, initiating a new 1/8-cycle step in the
periodic progression of RGB adjustments.
A program written in this way would exhibit a large jitter in the times at which
the RGB values are changed. This is due to the lumpiness in the tick counts
returned by the GetTickCount function. The lumpiness may be studied separately
by running a simple loop with C=GetTickCount, followed by writing the result
C to a file. Inspection shows that C has jumped every 14 or 15 milliseconds,
between long stretches of constant values. Since for a 1/2 Hz image intensity
modulation the 1/8-cycle phase points are 250 ms apart, the lumpiness of 14
or 15 ms in the tick count would cause considerable inaccuracy. The full extrapolation
procedure 61 is introduced in order to diminish the jitter to acceptable levels.
The procedure works by refining the heavy-line staircase function shown in FIG.
8, using the slope RR of a recent staircase step to accurately determine the
loop count 89 at which the loop controled by 60 needs to be exited. Details
of the extrapolation procedure are shown in FIG. 7 and illustrated in FIG. 8.
The procedure starts at 70 with both flags off, and CR=0, because of the assignment
in 59 or 62 in FIG. 6. A tick count M is obtained at 71, and the remaining time
MR to the next phase point is computed in 72. Conditions 77 and 73 are not satisfied
and therefore passed vertically in the flow chart, so that only the delay block
74 and the assignments 75 are executed. Condition 60 of FIG. 6 is checked and
found to be satisfied, so that the extrapolation procedure is reentered. The
process is repeated until the condition 73 is met when the remaining time MR
jumps down through the 15 ms level, shown in FIG. 8 as the transition 83. The
condition 73 then directs the logic flow to the assignments 76, in which the
number DM labeled by 83 is computed, and FLG1 is set. The computation of DM
is required for finding the slope RR of the straight-line element 85. One also
needs the "Final LM" 86, which is the number of loops traversed from step 83
to the next downward step 84, here shown to cross the MR=0 axis. The final LM
is determined after repeatedly incrementing LM through the side loop entered
from the FLG1=1 condition 77, which is now satisfied since FLG1 was set in step
76. At the transition 84 the condition 78 is met, so that the assignments 79
are executed. This includes computation of the slope RR of the line element
85, setting FLG2, and resetting FLG1. From here on, the extrapolation procedure
increments CR in steps of RR while skipping tick counts until condition 60 of
FIG. 6 is violated, the loop is exited, and the RGB values are adjusted.
A delay block 74 is used in order to stretch the time required for traversing
the extrapolation procedure. The block can be any computation intensive subroutine
such as repeated calculations of tangent and arc tangent functions.
As shown in step 56 of FIG. 6, the timer interval TT is set to 4/10 of the time
TA from one RGB adjustment point to the next. Since the timer runs in the background,
this arrangement provides an opportunity for execution of other processes such
as user adjustment of frequency or amplitude of the pulses.
The adjustment of the frequency and other pulse parameters of the image intensity
modulation can be made internally, i.e., within the running program. Such internal
control is to be distinguished from the external control provided, for instance,
in screen savers. In the latter, the frequency of animation can be modified
by the user, but only after having exited the screen saver program. Specifically,
in Windows 95(R) or Windows 98(R), to change the animation frequency requires
stopping the screen saver execution by moving the mouse, whereafter the frequency
may be adjusted through the control panel. The requirement that the control
be internal sets the present program apart from so-called banners as well.
The program may be run on a remote computer that is linked to the user computer,
as illustrated in FIG. 9. Although the monitor 2, labeled "MON", is connected
to the computer 31', labeled "COMPUTER", the program that pulses the images
on the monitor 2 runs on the remoter computer 90, labeled "REMOTE COMPUTER",
which is connected to computer 31' through a link 91 which may in part belong
to a network. The network may comprise the Internet 92.
The monitor of a television set emits an electromagnetic field in much the same
way as a computer monitor. Hence, a TV may be used to produce screen emissions
for the purpose of nervous system manipulation. FIG. 5 shows such an arrangement,
where the pulsing of the image intensity is achieved by inducing a small slowly
pulsing shift in the frequency of the RF signal that enters from the antenna.
This process is here called "frequency wobbling" of the RF signal. In FM TV,
a slight slow frequency wobble of the RF signal produces a pseudo-dc signal
level fluctuation in the composite video signal, which in turn causes a slight
intensity fluctuation of the image displayed on the monitor in the same manner
as discussed above for the modulator of FIG. 2. The frequency wobbling is induced
by the wobbler 44 of FIG. 5 labeled "RFM", which is placed in the antenna line
43. The wobbler is driven by the pulse generator 6, labeled "GEN". The subject
can adjust the frequency and the amplitude of the wobble through the tuning
control 7 and the amplitude control 41. FIG. 10 shows a block diagram of the
frequency wobbler circuit that employs a variable delay line 94, labelled "VDL".
The delay is determined by the signal from pulse generator 6, labelled "GEN".
The frequency of the pulses can be adjusted with the tuning control 7. The amplitude
of the pulses is determined by the unit 98, labelled "MD", and can be adjusted
with the amplitude control 41. Optionally, the input to the delay line may be
routed through a preprocessor 93, labelled "PRP", which may comprise a selective
RF amplifier and down converter; a complimentary up conversion should then be
performed on the delay line output by a postprocessor 95, labelled "POP". The
output 97 is to be connected to the antenna terminal of the TV set.
The action of the variable delay line 94 may be understood as follows. Let periodic
pulses with period L be presented at the input. For a fixed delay the pulses
would emerge at the output with the same period L. Actually, the time delay
T is varied slowly, so that it increases approximately by LdT/dt between the
emergence of consecutive pulses at the device output. The pulse period is thus
increased approximately by
In terms of the frequency .intg., Eq. (4) implies approximately
For sinusoidal delay T(t) with amplitude b and frequency g, one has
which shows the frequency wobbling. The approximation is good for gb<<1,
which is satisfied in practice. The relative frequency shift amplitude 2.pi.gb
that is required for effective image intensity pulses is very small compared
to unity. For a pulse frequency g of the order of 1 Hz, the delay may have to
be of the order of a millisecond. To accomodate such long delay values, the
delay line may have to be implemented as a digital device. To do so is well
within the present art. In that case it is natural to also choose digital implementations
for the pulse generator 6 and the pulse amplitude controller 98, either as hardware
or as software.
Pulse variability may be introduced for alleviating the need for precise tuning
to a resonance frequency. This may be important when sensory resonance frequencies
are not precisely known, because of the variation among individuals, or in order
to cope with the frequency drift that results from chemical detuning that is
discussed in the '874 patent. A field with suitably chosen pulse variability
can then be more effective than a fixed frequency field that is out of tune.
One may also control tremors and seizures, by interfering with the pathological
oscillatory activity of neural circuits that occurs in these disorders. Electromagnetic
fields with a pulse variability that results in a narrow spectrum of frequencies
around the frequency of the pathological oscillatory activity may then evoke
nerve signals that cause phase shifts which diminish or quench the oscillatory
activity.
Pulse variability can be introduced as hardware in the manner described in the
'304 patent. The variability may also be introduced in the computer program
of FIG. 6, by setting FLG3 in step 68, and choosing the amplitude B of the frequency
fluctuation. In the variability routine 46, shown in some detail in FIG. 13,
FLG3 is detected in step 47, whereupon in steps 48 and 49 the pulse frequency
F is modified pseudo randomly by a term proportional to B, every 4th cycle.
Optionally, the amplitude of the image intensity pulsing may be modified as
well, in similar fashion. Alternatively, the frequency and amplitude may be
swept through an adjustable ramp, or according to any suitable schedule, in
a manner known to those skilled in the art. The pulse variability may be applied
to subliminal image intensity pulses.
When an image is displayed by a TV monitor in response to a TV broadcast, intensity
pulses of the image may simply be imbedded in the program material. If the source
of video signal is a recording medium, the means for pulsing the image intensity
may comprise an attribute of recorded data. The pulsing may be subliminal. For
the case of a video signal from a VCR, the pertinent data attribute is illustrated
in FIG. 11, which shows a video signal record on part of a video tape 28. Depicted
schematically are segments of the video signal in intervals belonging to lines
in three image frames at different places along the tape. In each segment, the
chroma signal 9 is shown, with its short-term average level 29 represented as
a dashed line. The short-term average signal level, also called the pseudo-dc
level, represents the luminance of the image pixels. Over each segment, the
level is here constant because the image is for simplicity chosen as having
a uniform luminance over the screen. However, the level is seen to vary from
frame to frame, illustrating a luminance that pulses slowly over time. This
is shown in the lower portion of the drawing, wherein the IRE level of the short-term
chroma signal average is plotted versus time. The graph further shows a gradual
decrease of pulse amplitude in time, illustrating that luminance pulse amplitude
variations may also be an attribute of the recorded data on the video tape.
As discussed, pulsing the luminance for fixed chrominance results in pulsing
of the image intensity.
Data stream attributes that represent image intensity pulses on video tape or
in TV signals may be created when producing a video rendition or making a moving
picture of a scene, simply by pulsing the illumination of the scene. This is
illustrated in FIG. 12, which shows a scene 19 that is recorded with a video
camera 18, labelled "VR". The scene is illuminated with a lamp 20, labelled
"LAMP", energized by an electric current through a cable 36. The current is
modulated in pulsing fashion by a modulator 30, labeled "MOD", which is driven
by a pulse generator 6, labelled "GENERATOR", that produces voltage pulses 35.
Again, pulsing the luminance but not the chrominance amounts to pulsing the
image intensity.
The brightness of monitors can usually be adjusted by a control, which may be
addressable through a brightness adjustment terminal. If the control is of the
analog type, the displayed image intensity may be pulsed as shown in FIG. 15,
simply by a pulse generator 6, labeled "GEN", that is connected to the brigthness
adjustment terminal 88 of the monitor 2, labeled "MON". Equivalent action can
be provided for digital brightness controls, in ways that are well known in
the art.
The analog component video signal from a DVD player may be modulated such as
to overlay image intensity pulses in the manner illustrated in FIG. 17. Shown
are a DVD player 102, labeled "DVD", with analog component video output comprised
of the luminance Y and chrominance C. The overlay is accomplished simply by
shifting the luminance with a voltage pulse from generator 6, labeled "GENERATOR".
The generator output is applied to modulator 106, labeled "SHIFTER". Since the
luminance Y is pulsed without changing the chrominance C, the image intensity
is pulsed. The frequency and amplitude of the image intensity pulses can be
adjusted respectively with the tuner 7 and amplitude control 107. The modulator
105 has the same structure as the modulator of FIG. 2, and the pulse amplitude
control 107 operates the potentiometer 15 of FIG. 2. The same procedure can
be followed for editing a DVD such as to overlay image intensity pulses, by
processing the modulated luminance signal through an analog-to-digital converter,
and recording the resulting digital stream onto a DVD, after appropriate compression.
Alternatively, the digital luminance data can be edited by electronic reading
of the signal, decompression, altering the digital data by software, and recording
the resulting digital signal after proper compression, all in a manner that
is well known in the art.
The mechanism whereby a CRT-type monitor emits a pulsed electromagnetic field
when pulsing the intensity of an image is illustrated in FIG. 14. The image
is produced by an electron beam 10 which impinges upon the backside 88 of the
screen, where the collisions excite phosphors that subsequently emit light.
In the process, the electron beam deposits electrons 18 on the screen, and these
electrons contribute to an electric field 3 labelled "E". The electrons flow
along the conductive backside 88 of the screen to the terminal 99 which is hooked
up to the high-voltage supply 40, labelled "HV". The circuit is completed by
the ground connection of the supply, the video amplifier 87, labeled "VA", and
its connection to the cathodes of the CRT. The electron beams of the three electron
guns are collectively shown as 10, and together the beams carry a current J.
The electric current J flowing through the described circuit induces a magnetic
field 39, labeled "B". Actually, there are a multitude of circuits along which
the electron beam current is returned to the CRT cathodes, since on a macroscopic
scale the conductive back surface 88 of the screen provides a continuum of paths
from the beam impact point to the high-voltage terminal 99. The magnetic fields
induced by the currents along these paths partially cancel each other, and the
resulting field depends on the location of the pixel that is addressed. Since
the beams sweep over the screen through a raster of horizontal lines, the spectrum
of the induced magnetic field contains strong peaks at the horizontal and vertical
frequencies. However, the interest here is not in fields at those frequencies,
but rather in emissions that result from an image pulsing with the very low
frequencies appropriate to sensory resonances. For this purpose a diffuse electron
current model suffices, in which the pixel discreteness and the raster motion
of the electron beams are ignored, so that the beam current becomes diffuse
and fills the cone subtended by the displayed image. The resulting low-frequency
magnetic field depends on the temporal changes in the intensity distribution
over the displayed image. Order-of-magnitude estimates show that the low-frequency
magnetic field, although quite small, may be sufficient for the excitation of
sensory resonances in subjects located at a normal viewing distance from the
monitor.
The monitor also emits a low-frequency electric field at the image pulsing frequency.
This field is due in part to the electrons 18 that are deposited on the screen
by the electron beams 10. In the diffuse electron beam model, screen conditions
are considered functions of the time t and of the Cartesian coordinates x and
y over a flat CRT screen.
The screen electrons 18 that are dumped onto the back of the screen by the sum
j(x,y,t) of the diffuse current distributions in the red, green, and blue electron
beams cause a potential distribution V(x,y,t) which is influenced by the surface
conductivity .sigma. on the back of the screen and by capacitances. In the simple
model where the screen has a capacitance distribution c(x,y) to ground and mutual
capacitances between parts of the screen at different potentials are neglected,
a potential distribution V(x,y,t) over the screen implies a surface charge density
distribution
and gives rise to a current density vector along the screen,
where grad.sub.s is the gradient along the screen surface. Conservation of electric
charge implies
where the dot over the voltage denotes the time derivative, and div.sub.s is
the divergence in the screen surface. The partial differential equation (9)
requires a boundary condition for the solution V(x,y,t) to be unique. Such a
condition is provided by setting the potential at the rim of the screen equal
to the fixed anode voltage. This is a good approximation, since the resistance
R.sub.r between the screen rim and the anode terminal is chosen small in CRT
design, in order to keep the voltage loss JR.sub.r to a minimum, and also to
limit low-frequency emissions.
Something useful can be learned from special cases with simple solutions. As
such, consider a circular CRT screen of radius R with uniform conductivity,
showered in the back by a diffuse electron beam with a spatially uniform beam
current density that is a constant plus a sinusoidal part with frequency .intg..
Since the problem is linear, the voltage V due to the sinusoidal part of the
beam current can be considered separately, with the boundary condition that
V vanish at the rim of the circular screen. Eq. (9) then simplifies to
where r is a radial coordinate along the screen with its derivative denoted
by a prime, .eta.=1/.sigma. is the screen resistivity, A the screen area, J
the sinusoidal part of the total beam current, and i=(-1), the imaginary unit.
Our interest is in very low pulse frequencies .intg. that are suitable for excitation
of sensory resonances. For those frequencies and for practical ranges for c
and .eta., the dimensionless number 2.pi..intg.cA.eta. is very much smaller
than unity, so that it can be neglected in Eq. (10). The boundary value problem
then has the simple solution ##EQU1##
In deriving (11) we neglected the mutual capacitance between parts of the screen
that are at different potentials. The resulting error in (10) is negligible
for the same reason that the i2.pi..intg.cA.eta. term in (10) can be neglected.
The potential distribution V(r) of (11) along the screen is of course accompanied
by electric charges. The field lines emanating from these charges run mainly
to conductors behind the screen that belong to the CRT structure and that are
either grounded or connected to circuitry with a low impedance path to ground.
In either case the mentioned conductors must be considered grounded in the analysis
of charges and fields that result from the pulsed component J of the total electron
beam current. The described electric field lines end up in electric charges
that may be called polarization charges since they are the result of the polarization
of the conductors and circuitry by the screen emission. To estimate the pulsed
electric field, a model is chosen where the mentioned conductors are represented
together as a grounded perfectly conductive disc of radius R, positioned a short
distance .delta. behind the screen, as depicted in FIG. 16. Since the grounded
conductive disc carries polarization charges, it is called the polarization
disc. FIG. 16 shows the circular CRT screen 88 and the polarization disc 101,
briefly called "plates". For small distances .delta., the capacitance density
between the plates of opposite polarity is nearly equal to .epsilon./.delta.,
where .epsilon. is the permittivity of free space. The charge distributions
on the screen and polarization disc are respectively .epsilon.V(r)/.delta.+q.sub.0
and -.epsilon.V(r)/.delta.+q.sub.0, where the .epsilon.V(r)/.delta. terms denote
opposing charge densities at the end of the dense field lines that run between
the two plates. That the part q.sub.0 is needed as well will become clear in
the sequel.
The charge distributions .epsilon.V(r)/.delta.+q.sub.0 and -.epsilon.V(r)/.delta.+q.sub.0
on the two plates have a dipole moment with the density ##EQU2##
directed perpendicular to the screen. Note that the plate separation .delta.
has dropped out. This means that the precise location of the polarization charges
is not critical in the present model, and further that .delta. may be taken
as small as desired. Taking .delta. to zero, one thus arrives at the mathematical
model of pulsed dipoles distributed over the circular CRT screen. The field
due to the charge distribution q.sub.0 will be calculated later.
The electric field induced by the distributed dipoles (12) can be calculated
easily for points on the centerline of the screen, with the result ##EQU3##
where V(0) is the pulse voltage (11) at the screen center, .rho. the distance
to the rim of the screen, and z the distance to the center of the screen. Note
that V(0) pulses harmonically with frequency .intg., because in (11) the sinusoidal
part J of the beam current varies in this manner.
The electric field (13) due to the dipole distribution causes a potential distribution
V(r)/2 over the screen and a potential distribution of -V(r)/2 over the polarization
disc, where V(r) is nonuniform as given by (11). But since the polarization
disc is a perfect conductor it cannot support voltage gradients, and therefore
cannot have the potential distribution -V(r)/2. Instead, the polarization disc
is at ground potential. This is where the charge distribution q.sub.0 (r) comes
in; it must be such as to induce a potential distribution V(r)/2 over the polarization
disc. Since the distance between polarization disc and screen vanishes in the
mathematical model, the potential distribution V(r)/2 is induced over the screen
as well. The total potential over the monitor screen thus becomes V(r) of (11),
while the total potential distribution over the polarization disc becomes uniformly
zero. Both these potential distributions are as physically required. The electric
charges q.sub.0 are moved into position by polarization and are partly drawn
from the earth through the ground connection of the CRT.
In our model the charge distribution q.sub.0 is located at the same place as
the dipole distribution, viz., on the plane z=0 within the circle with radius
R. At points on the center line of the screen, the electric field due to the
monopole distribution q.sub.0 is calculated in the following manner. As discussed,
the monopoles must be such that they cause a potential .phi..sub.0 that is equal
to V(r)/2 over the disc with radius R centered in the plane z=0. Although the
charge distribution q.sub.0 (r) is uniquely defined by this condition, it cannot
be calculated easily in a straightforward manner. The difficulty is circumvented
by using an intermediate result derived from Excercise 2 on page 191 of Kellogg
(1953), where the charge distribution over a thin disc with uniform potential
is given. By using this result one readily finds the potential .phi.*(z) on
the axis of this disc as ##EQU4##
where .beta.(R.sub.1) is the angle subtended by the disc radius R.sub.1, as
viewed from the point z on the disc axis, and V* is the disc potential. The
result is used here in an attempt to construct the potential .phi..sub.0 (z)
for a disc with the nonuniform potential V(r)/2, by the ansatz of writing the
field as due to a linear combination of abstract discs with various radii R.sub.1
and potentials, all centered in the plane z=0. In the ansatz the potential on
the symmetry axis is written ##EQU5##
where W is chosen as the function 1-R.sub.1.sup.2 /R.sup.2, and the constants
a and b are to be determined such that the potential over the plane z=0 is V(r)/2
for radii r ranging from 0 to R, with V(r) given by (11). Carrying out the integration
in (15) gives
In order to find the potential over the disc r<R in the plane z=0, the function
.phi..sub.0 (z) is expanded in powers of z/R for 0<z<R, whereafter the
powers z.sup.n are replaced by r.sup.n P.sub.n (cos.theta.), where the P.sub.n
are Legendre polynomials, and (r,.theta.) are symmetric spherical coordinates
centered at the screen center. This procedure amounts to a continuation of the
potential from the z-axis into the half ball r<R, z>0, in such a manner
that the Laplace equation is satisfied. The method is discussed by Morse and
Feshbach (1953). The "Laplace continuation" allows calculation of the potential
.phi..sub.0 along the surface of the disc r<R centered in the plane z=0.
The requirement that this potential be V(r)/2 with the function V(r) given by
(11) allows solving for the constants a and b, with the result
Using (17) in (16) gives ##EQU6##
and by differentiation with respect to z one finally finds ##EQU7##
for the electric field on the center line of the screen brought about by the
charge distribution q.sub.0 (z).
The center-line electric field is the sum of the part (13) due to distributed
pulsed dipoles and part (19) due to distributed pulsed monopoles. Although derived
for circular screens, the results may serve as an approximation for other shapes,
such as the familiar rounded rectangle, by taking R as the radius of a circle
that has the same area as the screen.
For two CRT-type monitors the pulsed electric field due to image intensity pulsing
has been measured at several points on the screen center line for pulse frequencies
of 1/2 Hz. The monitors were the 15" computer monitor used in the sensory resonance
experiments mentioned above, and a 30" TV tube. The experimental results need
to be compared with the theory derived above. Since R is determined by the screen
area, the electric fields given by (13) and (19) have as only free parameter
the pulse voltage V(0) at the screen center. The amplitude of this voltage can
therefore be determined for the tested monitors by fitting the experimental
data to the theoretical results. Prior to fitting, the data were normalized
to an image that occupies the entire screen and is pulsed uniformly with a 100%
intensity amplitude. The results of the one-parameter fit are displayed in FIG.
18, which shows the theoretical graph 100, together with the normalized experimental
data points 103 for the 15- computer monitor and for the 30" TV tube. FIG. 18
shows that the developed theory agrees fairly well with the experimental results.
From the best fit one can find the center-screen voltage pulse amplitudes. The
results, normalized as discussed above, are .vertline.V(0).vertline.=266.2 volt
for the 15" computer monitor and .vertline.V(0).vertline.=310.1 volt for the
30" TV tube. With these amplitudes in hand, the emitted pulsed electric field
along the center line of the monitors can be calculated from the sum of the
fields (13) and (19). For instance, for the 15" computer monitor with 1.8% RGB
pulse modulation used in the 1/2 Hz sensory resonance experiments mentioned
above, the pulsed electric field at the center of the subject, located at z=70
cm on the screen center line, is calculated as having an amplitude of 0.21 V/m.
That such a pulsed electric field, applied to a large portion of the skin, is
sufficient for exciting the 1/2 Hz sensory resonance is consistent with experimental
results discussed in the '874 patent.
In deriving (11), the dimensionless number 2.pi..intg.cA.eta. was said to be
much smaller than unity. Now that the values for .vertline.V(0).vertline. are
known, the validity of this statement can be checked. Eq. (11) implies that
.vertline.V(0).vertline. is equal to .eta..vertline.J.vertline./4.pi.. The sum
of the beam currents in the red, green, and blue electron guns for 100% intensity
modulation is estimated to have pulse amplitudes .vertline.J.vertline. of 0.5
mA and 2.0 mA respectively for the 15" computer monitor and the 30" TV tube.
Using the derived values for .vertline.V(0).vertline., one arrives at estimates
for the screen resistivity .eta. as 6.7 M.OMEGA./square and 1.9 M.OMEGA./square
respectively for the 15" computer monitor and the 30" TV tube. Estimating the
screen capacity cA as 7 pf and 13 pf, 2.pi..intg.cA.eta. is found to be 148.times.10.sup.-6
and 78.times.10.sup.-6, respectively for the 15" computer monitor and the 30"
TV tube. These numbers are very small compared to unity, so that the step from
(10) to (11) is valid.
The following procedures were followed in preparing pulsed images for the field
measurements. For the 15" computer monitor the images were produced by running
the VB6 program discussed above. The pulsed image comprised the full screen
with basic RGB values chosen uniformly as R=G=B=127, with the exception of an
on/off button and a few data boxes which together take up 17% of the screen
area. The image intensity was pulsed by modifying the R, G, and B values by
integer-rounded sine functions .DELTA.R(t), .DELTA.G(t), and .DELTA.B(t), uniformly
over the image, except at the button and the data boxes. The measured electric
field pulse amplitudes were normalized to a pulsed image that occupies all of
the screen area and has 100% intensity modulation for which the image pulses
between black and the maximum intensity, for the fixed RGB ratios used. The
image intensity depends on the RGB values in a nonlinear manner that will be
be discussed. For the measurements of the pulsed electric field emitted by 30"
TV tube, a similar image was used as for the 15" computer monitor. This was
done by playing back a camcorder recording of the computer monitor display when
running the VB6 program, with 40% pulse modulation of R, G, and B.
In front of the monitor, i.e., for z>0, the parts (13) and (19) contribute
about equally to the electric field over a practical range of distances z. When
going behind the monitor where z is negative the monopole field flips sign so
that the two parts nearly cancel each other, and the resulting field is very
small. Therefore, in the back of the CRT, errors due to imperfections in the
theory are relatively large. Moreover our model, which pretends that the polarization
charges are all located on the polarization disc, fails to account for the electric
field flux that escapes from the outer regions of the back of the screen to
the earth or whatever conductors happen to be present in the vincinity of the
CRT. This flaw has relatively more serious consequences in the back than in
front of the monitor.
Screen emissions in front of a CRT can be cut dramatically by using a grounded
conductive transparent shield that is placed over the screen or applied as a
coating. Along the lines of our model, the shield amounts to a polarization
disc in front of the screen, so that the latter is now sandwiched between to
grounded discs. The screen has the pulsed potential distribution V(r) of (11),
but no electric flux can escape. The model may be modified by choosing the polarization
disc in the back somewhat smaller than the screen disc, by a fraction that serves
as a free parameter. The fraction may then be determined from a fit to measured
fields, by minimizing the relative standard deviation between experiment and
theory.
In each of the electron beams of a CRT, the beam current is a nonlinear function
of the driving voltage, i.e., the voltage between cathode and control grid.
Since this function is needed in the normalization procedure, it was measured
for the 15" computer monitor that has been used in the 1/2 Hz sensory resonance
experiments and the electric field measurements. Although the beam current density
j can be determined, it is easier to measure the luminance, by reading a light
meter that is brought right up to the monitor screen. With the RGB values in
the VB6 program taken as the same integer K, the luminance of a uniform image
is proportional to the image intensity I. The luminance of a uniform image was
measured for various values of K. The results were fitted with
where c.sub.1 is a constant. The best fit, with 6.18% relative standard deviation,
was obtained for .gamma.=2.32.
Screen emissions also occur for liquid crystal displays (LCD). The pulsed electric
fields may have considerable amplitude for LCDs that have their driving electrodes
on opposite sides of the liquid crystal cell, for passive matrix as well as
for active matrix design, such as thin film technology (TFT). For arrangements
with in-plane switching (IPS) however, the driving electrodes are positioned
in a single plane, so that the screen emission is very small. For arrangements
other than IPS, the electric field is closely approximated by the fringe field
of a two-plate condenser, for the simple case that the image is uniform and
extends over the full screen. For a circular LCD screen with radius R, the field
on the center line can be readily calculated as due to pulsed dipoles that are
uniformly distributed over the screen, with the result
where E.sub.d (z) is the amplitude of the pulsed electric field at a distance
z from the screen and V is a voltage pulse amplitude, in which the aperture
ratio of the LCD has been taken into account. Eq. (21) can be used as an approximation
for screens of any shape, by taking R as the radius of a circle with the same
area as the screen. The result applies to the case that the LCD does not have
a ground connection, so that the top and bottom electrodes are at opposite potential,
i.e., V/2 and -V/2.
If one set of LCD electrodes is grounded, monopoles are needed to keep these
electrodes at zero potential, much as in the case of a CRT discussed above.
The LCD situation is simpler however, as there is no charge injection by electron
beams, so that the potentials on the top and bottom plates of the condenser
in the model are spatially uniform. From (14) it is seen that monopoles, distributed
over the disc of radius R in the plane z=0 such as to provide on the disc a
potential V/2, induce on the symmetry axis a potential ##EQU8##
Differentiating with respect to z gives the electric field on the symmetry axis
##EQU9##
induced by the pulsed monopoles. For an LCD with one set of electrodes grounded,
the pulsed electric field for screen voltage pulse amplitude V at a distance
z from the screen on the center line has an amplitude that is the sum of the
parts (21) and (23). The resultant electric field in the back is relatively
small, due to the change in sign in the monopole field that is caused by the
factor z/.vertline.z.vertline.. Therefore, screen emissions in front of an LCD
can be kept small simply by having the grounded electrodes in front.
As a check on the theory, the pulsed electric field emitted by the 3" LCD-TFT
color screen of the camcorder mentioned above has been measured at eleven points
on the center line of the screen, ranging from 4.0 cm to 7.5 cm. The pulsed
image was produced by playing back the video recording of the 15" computer monitor
that was made while running the VB6 program discussed above, for a image intensity
pulse frequency of 1/2 Hz, R=G=B=K, modulated around K=127 with an amplitude
.DELTA.K=51. After normalization to a uniform full screen image with 100% intensity
modulation by using the nonlinear relation (20), the experimental data were
fitted to the theoretical curve that expresses the sum of the fields (21) and
(23). The effective screen pulse voltage amplitude V was found to be 2.1 volt.
The relative standard deviation in V for the fit is 5.1%, which shows that theory
and experiment are in fairly good agreement.
Certain monitors can cause excitation of sensory resonances even when the pulsing
of displayed images is subliminal, i.e., unnoticed by the average person. When
checking this condition on a computer monitor, a problem arises because of the
rounding of RGB values to integers, as occurs in the VB6 program. For small
pulse amplitude the sine wave is thereby distorted into a square wave, which
is easier to spot. This problem is alleviated somewhat by choosing .DELTA.R=0,
.DELTA.G=0, and .DELTA.B=2, since then the 8 rounded sine functions around the
unit circle, multiplied with the pulse amplitude .DELTA.B=2 become the sequence
1, 2 11 2, 1, -1 -2, -2, -1, etc, which is smoother to the eye than a square
wave. Using the VB6 program and the 15" computer monitor mentioned above with
R=71, G=71, and B=233, a 1/2 Hz pulse modulation with amplitudes .DELTA.R=.DELTA.G=0
and .DELTA.B=2 could not be noticed by the subject, and is therefore considered
subliminal. It is of interest to calculate the screen emission for this case,
and conduct a sensory resonance experiment as well. A distance z=60 cm was chosen
for the calculation and the experiment. Using Eq. (20), the image intensity
pulse modulation for the case is found to be 1.0% of the maximum intensity modulation.
Using R=13.83 cm together with .vertline.V(0).vertline.=266.2 V for the 15"
computer monitor, and the theoretical graph 100 of FIG. 18, the pulsed electric
field at z=60 cm was found to have an amplitude of 138 mV/m. In view of the
experimental results discussed in the '874 and '922 patents, such a field, used
at a pulse frequency chosen appropriately for the 1/2 Hz sensory resonance and
applied predominantly to the face, is expected to be sufficient for exciting
the 1/2 Hz sensory resonance. A confirmation experiment was done by running
the VB6 program with the discussed settings and the 15" monitor. The center
of the subject's face was positioned on the screen center line, at a distance
of 60 cm from the screen. A frequency sweep of -0.1% per ten cycles was chosen,
with an initial pulse frequency of 34 ppm. Full ptosis was experienced by the
subject at 20 minutes into the run, when the pulse frequency was f=31.76 ppm.
At 27 minutes into the run, the frequency sweep was reversed to +0.1% per ten
cycles. Full ptosis was experienced at f=31.66 ppm. At 40 minutes into the run,
the frequency sweep was set to -0.1% per ten cycles. Full ptosis occurred at
f=31.44 ppm. The small differences in ptosis frequency are attributed to chemical
detuning, discussed in the Background Section. It is concluded that the 1/2
Hz sensory resonance was excited in this experiment by screen emissions from
subliminal image pulsing on the 15" computer monitor at a distance of 60 cm.
For each implementation and embodiment discussed, the image pulsing may be subliminal.
The human eye is less sensitive to changes in hue than to changes in brightness.
In composite video this fact allows using a chrominance bandwidth that is smaller
than the luminance bandwidth. But it also has the consequence that pulsing of
the chrominance for fixed luminance allows larger pulse amplitudes while staying
within the subliminal pulse regime. Eq. (3) shows how to pulse the chrominance
components R-Y and B-Y while keeping Y fixed; for the change in pixel intensity
one then has
Luminance pulses with fixed chrominance give a change in pixel intensity
Of course, pure chrominance pulses may be combined with pure luminance pulses;
an instance of such combination has been mentioned above.
The subliminal region in color space needs to be explored to determine how marginally
subliminal pulses .DELTA.R, .DELTA.G, and .DELTA.B depend on RGB values. Prior
to this, the condition for image pulses to be subliminal should not be phrased
solely in terms of the percentage of intensity pulse amplitude. The subliminal
image pulsing case considered above, where the monitor is driven by a VB6 computer
program with R=G=71, B=233, and .DELTA.R=.DELTA.G=0, .DELTA.B=2 for full-screen
images will be referred to as "the standard subliminal image pulsing".
In the interest of the public we need to know the viewing distances at which
a TV with subliminally pulsed images can cause excitation of sensory resonances.
A rough exploration is reported here which may serve as starting point for further
work. The exploration is limited to estimating the largest distance z=z.sub.max
along the center line of the 30" TV at which screen emissions can excite the
1/2 Hz resonance, as determined by the ptosis test. The TV is to display an
image which undergoes the standard subliminal pulsing as defined above. It would
be best to perform this test with the 30" TV on which the subliminally pulsed
images are produced by means of a video. Since such a video was not available,
the ptosis test was conducted instead with a pulsed electric field source consisting
of a small grounded doublet electrode of the type discussed in the '874 patent.
The doublet was driven with a sinusoidal voltage of 10 V amplitude, and the
center of mass of the subject was located on the center line of the doublet
at a distance z=z.sub.d =323 cm. The doublet electrodes are rectangles of 4.4
cm by 4.7 cm. At the large distance z.sub.d there is whole-body exposure to
the field, so that the bulk effect discussed in the '874 patent comes into play,
as is expected to happen also at the distance z.sub.max from the 30" TV monitor.
The subject was facing the "hot" electrode of the doublet, so that at the subject
center the electric field was the sum of the parts (21) and (23), for positive
values of z. It was thought important to use a sine wave, since that would be
the "commercially" preferred pulse shape which allows larger pulse amplitudes
without being noticed. The only readily available sine wave generator with the
required voltage was an oscillator with a rather coarse frequency control that
cannot be set accurately, although the frequency is quite stable and can be
measured accurately. For the experiment a pulse frequency of 0.506 Hz was accepted,
although it differs considerably from the steady ptosis frequency for this case.
The subject experienced several ptosis cycles of moderate intensity, starting
8 minutes into the experiment run. It is concluded that the 1/2 Hz sensory resonance
was excited, and that the stimulating field was close to the weakest field capable
of excitation. From Eqs. (21) and (23), the electric field pulse amplitude at
the center of mass of the subject was found to be 7.9 mV/m. That an electric
field with such a small pulse amplitude, applied to the whole body, is capable
of exciting the 1/2 Hz sensory resonance is consistent with experimental results
reported in the '874 patent, although these were obtained for the 2.4 Hz resonance.
Next, the distance z.sub.max was determined at which the 30" TV tube with 1%
image intensity pulse amplitude produces an electric field with a pulse amplitude
of 7.9 mV/m, along the center line of the screen. From Eqs. (13) and (19) one
finds z.sub.max =362.9 cm. At more than 11 feet, this is a rather large distance
for viewing a 30" TV. Yet, the experiment and theory discussed show that the
1/2 Hz sensory resonance can be excited at this large distance, by pulsing the
image intensity subliminally. Of course, the excitation occurs as well for a
range of smaller viewing distances. It is thus apparent that the human nervous
system can be manipulated by screen emissions from subliminal TV image pulses.
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The invention is not limited by the
embodiments shown in the drawings and described in the specification, which
are given by way of example and not of limitation, but only in accordance with
the scope of the appended claims.
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