U.S. patent application number 15/018611 was filed with the patent office on 2016-06-02 for systems and methods for optically induced cutaneous sensation.
The applicant listed for this patent is Pine Development Corporation. Invention is credited to Alexander A. Brownell, William J. Yu.
Application Number | 20160154463 15/018611 |
Document ID | / |
Family ID | 51686409 |
Filed Date | 2016-06-02 |
United States Patent
Application |
20160154463 |
Kind Code |
A1 |
Yu; William J. ; et
al. |
June 2, 2016 |
SYSTEMS AND METHODS FOR OPTICALLY INDUCED CUTANEOUS SENSATION
Abstract
The present disclosure relates to systems and methods for
inducing a cutaneous sensation in a user of an electronic device.
Such systems and methods may include a stimulation system
configured to generate an output operable to excite neural tissue.
An interface component may be configured to direct the output of
the stimulation system onto a target area of skin of the user, and
a controller may be configured to generate a control signal to
cause the stimulation system to modify one or more characteristics
of the output of the stimulation system in order to induce a
cutaneous sensation. The cutaneous sensation may be based on a
tactile application executable on the electronic device that is
configured to generate a representation of a simulated object.
Further, a stimulation profile may represent at least one present
stimulation area and at least one prior stimulation area.
Inventors: |
Yu; William J.; (Mountain
View, CA) ; Brownell; Alexander A.; (Bountiful,
UT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Pine Development Corporation |
Mountain View |
CA |
US |
|
|
Family ID: |
51686409 |
Appl. No.: |
15/018611 |
Filed: |
February 8, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14073743 |
Nov 6, 2013 |
9257021 |
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15018611 |
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61811552 |
Apr 12, 2013 |
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61842175 |
Jul 2, 2013 |
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61887861 |
Oct 7, 2013 |
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Current U.S.
Class: |
715/702 |
Current CPC
Class: |
G06F 3/0416 20130101;
G06F 3/0488 20130101; G06F 3/016 20130101; G08B 6/00 20130101; G06F
3/011 20130101 |
International
Class: |
G06F 3/01 20060101
G06F003/01 |
Claims
1. A system configured to induce a cutaneous sensation in a user of
an electronic device based upon a tactile application executable on
the electronic device, the system comprising: a stimulation system
configured to generate an output operable to excite neural tissue;
an interface component configured to direct the output of the
stimulation system onto a target area of skin of the user; and a
controller configured to generate a control signal to cause the
stimulation system to modify one or more characteristics of the
output of the stimulation system in order to induce a cutaneous
sensation based on: a tactile application executable on the
electronic device, the tactile application configured to generate a
representation of a simulated object, and a stimulation profile
representing at least one present stimulation area and at least one
prior stimulation area, the profile further representing a time
associated with a prior stimulation of the prior stimulation
area.
2. The system of claim 1, wherein the stimulation system is
configured to adjust the stimulation profile to account for thermal
conduction of stimulated tissue, heat capacity of stimulated
tissue, evaporative cooling, and blood perfusion of stimulated
tissue.
3. The system of claim 1, wherein the controller is configured to
adjust the profile in proximity to an angled portion of a
stimulation profile.
4. The system of claim 3, wherein adjustment of the profile
comprises increasing a distance between a plurality of stimulation
points in proximity to the angled portion.
5. The system of claim 3, wherein adjustment of the profile
comprises decreasing the intensity of the output in proximity to
the angled portion to provide a uniform sensation in proximity to
the angled portion.
6. The system of claim 1, wherein the controller is further
configured to deliver a plurality of punctate stimuli to a
plurality of points in a moving pattern, the moving pattern
comprising a first frame and a second frame comprising at least one
point in the second frame that is absent from the first frame.
7. The system of claim 6, wherein the moving pattern, and the
controller is further configured to identify a plurality of points
in common between the first frame and the second frame and to
maintain stimulation of at least one of the plurality of points in
common between the first frame and the second frame.
8. The system of claim 7, wherein the controller is further
configured to adjust an order in which the plurality of points are
stimulated based on an indication in the stimulation profile of
prior stimulation to create a uniform frequency of stimulation at
the plurality of points.
9. The system of claim 7, wherein the controller increases the
output at a first point stimulated for a first time as a result of
a movement of the pattern to create the uniform sensation at a
point of stimulation in the second frame and absent in the first
frame.
10. The system of claim 1, wherein the controller is configured to
direct the output through a range of positions at a variable
speed.
11. The system of claim 11, wherein the moving pattern represents a
topography of a simulated object based on variation of the speed
with which the output moves through the range of positions.
12. The system of claim 1, wherein the stimulation profile further
represents a topography of a simulated object based on a variation
in at least one of a number of illumination spots, a spacing
between a plurality of illumination spots, an amplitude, a pulse
width, a spot size, a frequency, a duty cycle, and a waveform.
13. The system of claim 1, wherein the stimulation system is
configured to emit electromagnetic radiation in one of a visible
spectrum and an infrared spectrum.
14. A method for inducing a cutaneous sensation in a user of an
electronic device based upon a tactile application executable on
the electronic device, the method comprising: generating an output
of a stimulation system operable to excite neural tissue; directing
the output of the stimulation system onto a target area of skin of
the user; generating a representation of simulated object using a
tactile application executable on the electronic device; generating
a stimulation profile representing at least one present stimulation
area and at least one prior stimulation area, the profile further
representing a time associated with a prior stimulation of the
prior stimulation area; modifying one or more characteristics of
the output of the stimulation system in order to induce a cutaneous
sensation based on the representation of the simulated object and
the stimulation profile.
15. The method of claim 14, wherein the stimulation system is
configured to adjust the stimulation profile to account for thermal
conduction of stimulated tissue, heat capacity of stimulated
tissue, evaporative cooling, and blood perfusion of stimulated
tissue.
16. The method of claim 14, further comprising adjusting the
profile in proximity to an angled portion of a stimulation
profile.
17. The method of claim 14, wherein adjusting the profile comprises
increasing a distance between a plurality of stimulation points in
proximity to the angled portion.
18. The method of claim 14, wherein adjusting the profile comprises
decreasing the intensity of the output in proximity to the angled
portion to provide a uniform sensation in proximity to the angled
portion.
19. The method of claim 14, further comprising delivering a
plurality of punctate stimuli to a plurality of points in a moving
pattern, the moving pattern comprising a first frame and a second
frame comprising at least one point in the second frame that is
absent from the first frame.
20. The method of claim 19, further comprising: identifying a
plurality of points in common between the first frame and the
second frame; maintaining stimulation of at least one of the
plurality of points in common between the first frame and the
second frame.
Description
RELATED APPLICATIONS
[0001] This is a continuation application of U.S. patent
application Ser. No. 14/073,743, filed on Nov. 6, 2013, and titled
"SYSTEMS AND METHODS FOR OPTICALLY INDUCED CUTANEOUS SENSATION,"
which is incorporated herein by reference in its entirety, which
claims the benefit under 35 U.S.C. .sctn.119(e) of U.S. Provisional
Patent Application No. 61/811,552, filed Apr. 12, 2013, and titled
"Algorithms and Hardware for Control of Light Induced Cutaneous
Sensation," which is incorporated herein by reference in its
entirety; of U.S. Provisional Patent Application No. 61/842,175,
filed Jul. 2, 2013, and titled "Non-Contact Interface," which is
incorporated herein by reference in its entirety; and of U.S.
Provisional Patent Application No. 61/887,861, filed Oct. 7, 2013,
and titled "Non-Contact Interface," which is incorporated herein by
reference in its entirety.
TECHNICAL FIELD
[0002] Presently disclosed are systems and methods related to the
stimulation of sensation either directly or indirectly using
directed electromagnetic radiation.
BRIEF SUMMARY
[0003] Electromagnetic radiation directed onto the superficial
tissue of a user may induce sensations similar to that of a
mechanical stimulus. In some embodiments, electromagnetic radiation
may also induce heating sensations. The use of these energies
directed at the tissue of a user may be used to convey many types
of information to the user, such as, but not limited to, the size,
shape, compliance, temperature, and texture of an object, text,
warnings, directional commands or feedback, and movement.
[0004] The techniques and systems described herein are generally
applicable to infrared and visible spectrum stimuli in both contact
surface stimulation embodiments and free-space (i.e., non-contact)
stimulation embodiments. The various embodiments may include a
controller that directs the energy from a single source or multiple
illumination sources through optics onto a user's tissue in such a
way that sensations are induced.
BRIEF DESCRIPTION OF DRAWINGS
[0005] FIG. 1A illustrates a conceptual representation of a stable
temperature field at equilibrium of a constant beam of optical
stimulation consistent with embodiments of the present
disclosure.
[0006] FIG. 1B illustrates a steady stimulation with a temperature
field at equilibrium with the later instantaneous addition of
second stimulus within the temperature field of the first beam
before any heating due to energy deposition of the second stimulus
consistent with embodiments of the present disclosure.
[0007] FIG. 1C illustrates an approximate steady state condition of
two incident beams that are sufficiently proximate for their
temperature field overlap and combine consistent with embodiments
of the present disclosure.
[0008] FIG. 1D illustrates an example where two stimulating beams
whose temperature fields have minor overlap consistent with
embodiments of the present disclosure.
[0009] FIG. 2A illustrates a stimulation profile including a curve
at a first time consistent with embodiments of the present
disclosure.
[0010] FIG. 2B illustrates the stimulation profile of FIG. 2A at a
second time and shows modification of the stimulation protocol to
reduce stimulation in areas where the curvature may cause
intensified stimulation consistent with embodiments of the present
disclosure.
[0011] FIG. 2C illustrates a stimulation profile including a corner
and variable spacing of stimulation points.
[0012] FIG. 2D illustrates an alternative to the stimulation
profile of FIG. 2C in which the stimulation points are spaced
evenly and in which the intensity of the stimulation is varied to
achieve consistent stimulation near the corner consistent with
embodiments of the present disclosure.
[0013] FIG. 3 illustrates a representation of a system configured
to rearrange an order of stimulation to achieve a steady frequency
of stimulation of each of a plurality of points in a moving array
of stimuli consistent with embodiments of the present
disclosure.
[0014] FIG. 4A illustrates a series of points of stimulation that
follow one another through a defined path each time the array of
points moves to a new position consistent with embodiments of the
present disclosure.
[0015] FIG. 4B illustrates a conceptual representation showing
movement of the stimulation profile shown in FIG. 4A in which the
movement of the stimulation profile is modified to stimulate the
same stimulation areas at successive times consistent with
embodiments of the present disclosure.
[0016] FIGS. 5A-5C show an example of a stimulation pattern over
time in which the initial pulses within a stimulation profile are
gradually removed until there is a single stimulation point
remaining.
[0017] FIG. 6A illustrates a conceptual representation showing
movement of a stimulation profile over five time intervals
consistent with embodiments of the present disclosure.
[0018] FIG. 6B illustrates a conceptual representation showing
movement of the stimulation profile shown in FIG. 6A in which the
movement of the stimulation profile is modified to stimulate the
same stimulation areas at successive time intervals consistent with
embodiments of the present disclosure.
[0019] FIG. 7A illustrates a conceptual representation at four time
intervals showing dynamic stimulation of a plurality of stimulation
points within an object to maintain object perception consistent
with embodiments of the present disclosure.
[0020] FIG. 7B illustrates a conceptual representing at four time
intervals showing growth of an object over time consistent with
embodiments of the present disclosure.
[0021] FIG. 8 illustrates a conceptual representation of an array
of stimulation points having different intensity to provide
information regarding a topography of an object consistent with
embodiments of the present disclosure.
[0022] FIG. 9 illustrates a functional block diagram of a system
for using optical stimulation consistent with embodiments of the
present disclosure.
[0023] FIG. 10A illustrates a conceptual representation of a system
configured to create variable cutaneous sensations associated with
stationary tissue consistent with embodiments of the present
disclosure.
[0024] FIG. 10B illustrates that over time, the stimulation profile
shown in FIG. 13A and representing a topography of a simulated
object, changes beneath the finger consistent with embodiments of
the present disclosure.
[0025] FIG. 11A illustrates a conceptual representation of a system
configured to create a cutaneous sensation by varying a stimulation
amplitude at a fixed location while a finger moves across the fixed
location consistent with embodiments of the present disclosure.
[0026] FIGS. 11B-11D illustrate three stimulation profiles that
represent a topography of a simulated object based on a speed of
the finger as it moves across the point of stimulation illustrated
in FIG. 11A consistent with embodiments of the present
disclosure.
[0027] FIGS. 11E-11G further illustrate that an amplitude of a
stimulation profile may vary as a result of a topography of a
simulated object consistent with embodiments of the present
disclosure.
[0028] FIG. 12A illustrates a representation of a sharp sensation
consistent with embodiments of the present disclosure.
[0029] FIG. 12B illustrates a representation of a dull sensation
consistent with embodiments of the present disclosure.
[0030] FIG. 13 illustrates various stimulation profiles configured
to rapidly induce a sensation and maintain a constant level of
sensation over time consistent with embodiments of the present
disclosure.
[0031] FIG. 14A illustrates an approximately circular pattern
created by a stimulating beam when the beam incidence is normal to
the tissue consistent with embodiments of the present
disclosure.
[0032] FIG. 14B illustrates an elliptical pattern created by the
stimulating beam when the stimulating beam is at a high angle of to
the tissue consistent with embodiments of the present
disclosure.
[0033] FIG. 15A illustrates a stimulation profile configured to use
movement over time to convey information regarding a surface
topography consistent with embodiments of the present
disclosure.
[0034] FIG. 15B illustrates that an inverse of the stimulation
profile illustrated in FIG. 15A may be used to convey information
regarding a surface topography consistent with embodiments of the
present disclosure.
DETAILED DESCRIPTION
[0035] Incident stimulation on the tissue, depending on the
wavelength, may raise the temperature of the tissue. The initial
tissue temperature may affect the stimulation threshold. In
general, as the initial tissue temperature increases, the
stimulation threshold to induce sensation decreases. Due to thermal
conductivity and heat capacity of the tissue as well as
contribution from blood flow, to name a few variables, the heat
introduced to the tissue at the stimulation site spreads into the
tissue surrounding that stimulation site. In the case of a single
point of sustained stimulation, such that the stimulation is a
repeating pulse or a sustained constant illumination, the tissue
temperature just before the beginning of the stimulation may be
nearly uniform with that of the immediately surrounding tissue.
During the initial moments of stimulation heat at the site of
stimulation may be concentrated in the area immediately adjacent to
the stimulation. Over time, heat at the stimulation site may
conduct radially to the surrounding tissues as well as axially. The
tissue surface poses a boundary to conduction.
[0036] Heat loss due to evaporative cooling, convection at the
tissue surface as well as radiative losses may dissipate heating
from stimulation. The spread of heat from stimulation may affect
other sites of potential stimulation. If there is a second point of
stimulation within the temperature field of the first stimulation
point, then the sensation threshold of the second may be lower. The
stimulation threshold may also eventually be decreased even if the
second stimulation point is outside the heated tissue of the first.
This may happen if the two temperature fields overlap, then the
heat dissipation will decrease for each field and the temperature
may increase at each stimulation point. As the number of
stimulation sites increases, the complexity of the interaction
increases. In tight groupings, many stimulation sites may each
require less energy than a single site that is stimulated alone
would. Taking these interactions into account, a controller of a
stimulation system may use intensity of stimulation, duration of
previous stimulation, proximity of other stimulation sites, thermal
conductivity, heat capacity of the tissue, among other variables,
to modulate a stimulation profile. In another embodiment,
temperature readings taken from the tissue surface using, such as,
but not limited to, an infrared thermographic imager or array or
pyrometer, can be used to estimate the subsurface temperature
distribution to determine the appropriate stimulation parameters to
decrease, maintain, or increase intensity of sensations. Each of
these variables may help predict the appropriate adjustment in the
stimulation energy to deliver at the various sites.
[0037] The embodiments of the disclosure will be best understood by
reference to the drawings, wherein like parts are designated by
like numerals throughout. It will be readily understood that the
components of the disclosed embodiments, as generally described and
illustrated in the figures herein, could be arranged and designed
in a wide variety of different configurations. Thus, the following
detailed description of the embodiments of the systems and methods
of the disclosure is not intended to limit the scope of the
disclosure, as claimed, but is merely representative of possible
embodiments of the disclosure. In addition, the steps of a method
do not necessarily need to be executed in any specific order, or
even sequentially, nor need the steps be executed only once, unless
otherwise specified.
[0038] In some cases, well-known features, structures or operations
are not shown or described in detail. Furthermore, the described
features, structures, or operations may be combined in any suitable
manner in one or more embodiments. It will also be readily
understood that the components of the embodiments, as generally
described and illustrated in the figures herein, could be arranged
and designed in a wide variety of different configurations.
[0039] Several aspects of the embodiments described will be
illustrated as software modules or components. As used herein, a
software module or component may include any type of computer
instruction or computer executable code located within a memory
device and/or transmitted as electronic signals over a system bus,
and/or a wired or wireless network. A software module or component
may, for instance, comprise one or more physical or logical blocks
of computer instructions, which may be organized as a routine,
program, object, component, data structure, etc., that performs one
or more tasks or implements particular abstract data types.
[0040] In certain embodiments, a particular software module or
component may comprise disparate instructions stored in different
locations of a memory device, which together implement the
described functionality of the module. Indeed, a module or
component may comprise a single instruction or many instructions,
and may be distributed over several different code segments, among
different programs, and across several memory devices. Some
embodiments may be practiced in a distributed computing environment
where tasks are performed by a remote processing device linked
through a communications network. In a distributed computing
environment, software modules or components may be located in local
and/or remote memory storage devices. In addition, data being tied
or rendered together in a database record may be resident in the
same memory device, or across several memory devices, and may be
linked together in fields of a record in a database across a
network.
[0041] Embodiments may be provided as a computer program product
including a non-transitory computer and/or machine-readable medium
having stored thereon instructions that may be used to program a
computer (or other electronic device) to perform processes
described herein. For example, a non-transitory computer-readable
medium may store instructions that, when executed by a processor of
a computer system, cause the processor to perform certain methods
disclosed herein. The non-transitory computer-readable medium may
include, but is not limited to, hard drives, floppy diskettes,
optical disks, CD-ROMs, DVD-ROMs, ROMs, RAMs, EPROMs, EEPROMs,
magnetic or optical cards, solid-state memory devices, or other
types of media/machine-readable medium suitable for storing
electronic and/or processor executable instructions.
[0042] FIGS. 1A-1D show a plurality of conceptual representations
of exemplary incident beams of stimulation from above the tissue
and isothermal lines 110, which are illustrated as dashed lines,
representing the temperature fields within the tissue. FIG. 1A
illustrates an example of a stable temperature field at equilibrium
of a constant beam of optical stimulation 100. The increased
temperature is highest at the center of the field directly beneath
the stimulation and the temperature decreases around that point.
FIG. 1B illustrates a steady stimulation with a temperature field
at equilibrium 101 with the later addition of a second stimulus 102
that is incident on tissue within the heated tissue temperature
field of the first beam 101, but has not yet resulted in
significant heat transfer to the tissue. The second stimulus 102
may require less energy to create an additional sensation because
the tissue temperature has been raised by the first stimulus
101.
[0043] FIG. 1C illustrates a conceptual representation of a steady
state condition of two incident beams 103 and 104 that are close
enough together for their individual temperature fields to overlap
and combine. The combined effect of the two incident beams may
reduce the energy required for each beam to induce a sensation.
[0044] FIG. 1D illustrates an example where two stimulating beams
105 and 106 are relatively far apart, but there is some minor
overlap and joining of the two temperature fields. In the
illustrated embodiment, the energy used to create two stimulation
points may exceed to the amount of energy used to create two points
of stimulation shown in FIG. 1C. The introduction of additional
stimulating beams in proximity to stimulating beams 105 and 106 may
decrease the intensity required of each of the beams to generate a
sensation. In other words, multiple stimulating beams illuminating
a corresponding number of stimulation points with overlapping
temperature fields may utilize less energy than the same number of
stimulating beams and stimulation points if the temperature fields
do not overlap. There is a distance beyond which there is no longer
a measurable effect and each of the stimulation beams requires the
same energy regardless of the number of other simultaneous stimuli
at or beyond this distance. This distance may represent diameter
the diameter of the increase in tissue temperature. The proximity
of beams with their resultant interaction becomes increasingly
complex when attempting to convey shape and movement. At curves and
corners, the heat fields of stimulation sites may overlap more than
in straight lines. This increased overlap may lower the sensation
threshold. If the stimuli are left at a constant level while the
threshold drops, the user may feel the curves and corners of shapes
or the change of direction of an object's movement more intensely
than the straight portions of an object or the straight movement
thereof.
[0045] FIGS. 2A-2D show two embodiments of stimulation protocols
that are modified based on proximity of stimulation sites. FIG. 2A
illustrates a curved path where empty circles 201 represent
possible points of stimulation along the predefined path and filled
circles 202 represent current points of stimulation. This example
shows a train of points following along the path in order. As the
path curves, the increased proximity of the stimulation points may
cause the sensation to become more intense if the energy of each
point of stimulation remains constant. FIG. 2B illustrates a space
203 in the path where one of the points is removed from the
stimulation in comparison to FIG. 2A. According to the embodiment
illustrated in FIGS. 2A and 2B, every fourth point around the
curved portion of the path is removed. The removal of these points
may allow for a uniformity of the sensation between the straighter
and the curved portions of the path. FIG. 2A illustrates the train
of stimuli in the straighter portion of the path. FIG. 2B
illustrates the train in the curved portion of the path. In this
example, the stimulus train is 6 points of stimulation that span
the gaps in the path. In other embodiments, the stimulation
algorithm removes stimuli during the time they would have
stimulated the gaps in the path. The length of the train may also
dynamically change to elicit the desired sensation. In alternative
embodiments, different stimulation patterns may be used to elicit a
desired stimulation profile. Such stimulation patterns may
selectively omit stimulation points, may vary the intensity of
stimulation, or implement other techniques for creating a constant
sensation, including, but not limited to, pulse width, amplitude,
spot size, speed of a train of stimuli, frequency, duty cycle,
waveform, and timing individual stimulations are delivered.
[0046] FIG. 2C illustrates an example of a corner which may be
illuminated or around which a train of stimuli might be directed.
Certain stimulation points in that path are removed to even out the
sensation. FIG. 2D illustrates another embodiment having the same
shape as FIG. 2C may also even out sensation around the corner. The
"x" within the hollow circle 204 indicates a site within the path
where the stimulation intensity may be lowered to even out the
sensation at the corner. These examples are not only applicable to
moving stimulation. These same principles apply to stationary
objects where curves and corners bring stimulation points closer
together in certain areas of the object represented. Increasing the
gaps between stimulation sites and lowering the stimulus intensity
may even out the sensation throughout the entire shape.
[0047] An even level of sensation is not always desirable. There
are situations in which intensification of curves and corners is
appropriate. There are also situations where the sensation
intensity may be raised further in those areas. This may be
accomplished by decreasing the spacing between stimulation sites or
increasing the intensity of stimulation at desired sites. Other
parameters that can be modified, include, but not limited to, pulse
width, amplitude, spot size, speed of a train of stimuli,
frequency, duty cycle, waveform, and timing individual stimulations
are delivered.
[0048] FIG. 3 illustrates a progression of an array of moving
points 301 following one another down a path. These points move in
order ABC following one another down the path in the direction
I-VII. The stimulation waveform 302 is repeated at a steady
frequency, f, in Hz and is of length 1/f in seconds. If the
stimulation waveform 302 were to always stimulate each point in
order of ABC, then each time the array of points moved to a new
position points B and C would be stimulated again more quickly than
these points would be based on a steady frequency. This figure
shows that at each point of the path the pulse is in the same
position relative to the stimulation waveform 302. For example,
position IV is first stimulated by point A in the second line of
the figure at the third pulse of the stimulation waveform. In the
third line of the figure the position IV is occupied by point B of
the train but is still stimulated by the third pulse of the
stimulation waveform. In the fourth line position IV is occupied by
point C and is still stimulated by the third pulse in the waveform.
By ensuring that each physical location is always stimulated during
the same portion of the stimulation waveform there is no shift in
frequency of stimulation at any point even when the array of points
moves.
[0049] As with many other stimulation parameters, the frequency of
intermittent stimulation at a single point affects the total energy
delivered and the intensity of the sensation. Increasing the
frequency of intermittent stimulation while leaving all other
stimulation parameters the same increases the intensity of the
stimulation. Decreasing the frequency also lessens the sensation
intensity. In certain embodiments, a controller may be configured
to adjust the output of a stimulation system to maintain an even
sensation at a plurality of stimulation areas. A steady sensation
may be created by maintaining a constant stimulation frequency or
by adjusting other parameters to compensate for potential
variations.
[0050] FIG. 4A illustrates a series of points of stimulation that
follow one another through a defined path each time the array of
points moves to a new position the second point occupies the point
previously occupied by the first, the third occupies the space of
the second and so on. The pattern illustrated in FIG. 4A, which may
be referred to herein as "caterpillaring." As shown in FIG. 4A the
initial points of a sensory region may be stimulated and then any
number of additional points along that path may be added
sequentially until the desired length of the "caterpillar" or train
of stimulating points is achieved. After the desired "caterpillar"
length is achieved the tracing of the intended shape continues and
the initial points are dropped as points farther along the path are
stimulated.
[0051] As shown in FIG. 4A, the initial point of stimulation is on
the far right. This point is stimulated, then after a given amount
of time the second point is added, as indicated by 410. Now two
points are stimulated. A third, fourth and fifth point is
eventually added as indicated by 420, 430 and 440 respectively. At
this point the caterpillar has reached the desired length and as
another point along the path is added to the stimulation the
initial point is dropped as shown by 450. 460 shows the progression
of the caterpillar to another set of points along the path dropping
the first two points of the path. In this example, the length of
the caterpillar is 5 points of stimulation. Such a "caterpillar" is
not limited to a specific length or number of individual points of
stimulation. A train of points of stimulation may trace out any
shape and at any speed. Each point of stimulation may be of similar
or different stimulation energies as desired to create the effect
at different times or physical locations within the shape. The
example shown deals with an initial lack of any stimulation and a
gradually emerging caterpillar, or growing train of stimulation
points. The caterpillar may also emerge at its full length or some
intermediate length immediately. The length of the caterpillar may
also change dynamically along the path. Many caterpillars may be
simultaneously moved around the tissue.
[0052] FIG. 4B illustrates a sensation that may be perceived by a
user as a result of a "caterpillaring" stimulation pattern at five
points of time consistent with one embodiment. The intensity of the
leading portions of a caterpillar may be of sufficient intensity to
elicit sensation alone, or they may be of lower energy and act to
prime the tissue so that later portions of the caterpillar elicit
sensation.
[0053] FIG. 4B may also represent a separate embodiment in which
the illumination pattern is that of a continuously directed beam
onto a curved path on the tissue rather than a series of distinct
points. Such application of the optical energy may be repeated at a
desired frequency in similar manner to the discrete points. The
continuous path is not limited to curves, but may represent any
shape and is not limited to a single continuous path. The intensity
of the stimulation may also vary throughout the path.
[0054] If in the stimulation program the array of points are always
stimulated in the same order in a cluster at the beginning of each
round of stimulation, then there may be increases in the frequency
for all stimulation points except for the leading point each time
the caterpillar moves to a new position. These increases in
frequency may increase the intensity of the stimulation
undesirably. Such considerations are applicable to stimulation
systems including a single illumination source and to systems
including multiple illumination sources. In the case of a system
including a single source of illumination, the stimulation pulses
are directed onto target tissue via some method of beam steering.
Each stimulation cycle may allow time at the initial site for
stimulation to reach a threshold, time for the steering mechanism
to redirect the beam as appropriate, and time to stimulate the next
point, and so on. Each pulse may remain in its place in the
stimulation cycle relative to the position of the stimulus site
rather than its place in the array of sites or the frequency of
stimulation at one or more points may be altered. Certain
embodiments consistent with the present disclosure may utilize
punctate stimuli to create sensation; however, the present
disclosure is also applicable to systems in which a stimulation
system utilizes a continuously moving beam.
[0055] FIGS. 5A-5C show an example of a stimulation pattern over
time in which the initial pulses within a stimulation profile are
gradually removed until there is a single stimulation point
remaining. The exemplary stimulation patterns illustrated in FIGS.
5A-5C demonstrate that in certain embodiments, a steady frequency
of stimulation may be maintained when removing stimulation points
from a stimulation profile. The gradual or immediate removal of one
or more stimulation points from a sensation is one technique that
may be used to represent a variety of shapes, objects or movements.
FIG. 5A illustrates an initial waveform 501, in which all points of
the shape are stimulated. In FIG. 5B the left-most point is taken
away, as indicated by 502. In FIG. 5C all points except the
right-most point is taken away. As illustrated in FIG. 5C, the
temporal position of the right-most pulse 403 may be maintained to
keep the stimulation frequency steady. In other embodiments, if
frequency of stimulation shifts, other parameters may be modified
to stimulate a constant sensation intensity.
[0056] When initially encountering an object, a user may have a
natural inclination to determine the object's characteristics by
touching the object and moving the user's finger or other skin
relative to that object in order to gather more information.
Movement of any shape across the tissue may be used to mimic the
tactile sensation of an object. Movement can be detected at a broad
range of speeds. As the shape moves faster, more energy may be used
to maintain the same level of sensation. Slower movement may use
less stimulation energy for a similar sensation intensity. If a
shape moving quickly retraces or recrosses a previously stimulated
area, the stimulation intensity may be lessened to preserve equal
sensation intensity. Certain embodiments incorporating this feature
may create a profile representing a present stimulation and prior
stimulation, together with a last time of stimulation associated
with each of the plurality of stimulation sites.
[0057] For certain shapes and stimulation patterns it may be
convenient to use a grid pattern for possible points of
stimulation. According to certain embodiments, a grid associated
with a stimulation pattern may be laid out such that there are any
number of divisions of possible points of stimulation. Cutaneous
sensations are subject to a differentiation threshold. If two
points of stimulation are closer together than the differentiation
threshold, the two separate points of stimulation are not
distinguishable as separate points, but rather are experienced as
part of a single continuous sensation. Point spacing of stimulated
shapes may be fixed or dynamic depending on the application and
desired sensation. One method of minimizing energy expended, in
order to maximize system efficiency, is to match the spacing of the
shape with the spacing of the movement path of that shape. The
movement of a shape across the tissue or the movement of the tissue
over a stationary stimulated shape may be considered and treated
similarly.
[0058] FIGS. 6A and 6B illustrate two exemplary stimulation
profiles using a grid system and showing a small hollow square
being moved across a field of stimulation from left to right. A
filled circle 601 in FIGS. 6A and 6B, represents a point of
stimulation, and an empty circle 602, represents a possible point
of stimulation in the field. Although FIGS. 6A and 6B depict a grid
having an even layout, other embodiments consistent with the
present disclosure need not be limited to even intervals. Shapes
movements may include, but are not limited to, translations,
rotations, inversions, reflections, growth, contractions, or
transformations.
[0059] The example shown in FIG. 6A uses a spacing of every other
possible point for the shape stimulated. In successive frames,
moving from left to right, the stimulation in FIG. 6A illustrates
that the shape moves to the next set of available points in the
grid. FIG. 6B illustrates an example in which the shape moves at
the same speed overall as in FIG. 6A: however, in FIG. 6B, at least
some of the same stimulation points are used in successive frames.
As discussed above, initiating a sensation may utilize more energy
than stimulating tissue that has already been stimulated.
Accordingly, the example shown in FIG. 6B may utilize less energy
to achieve a similar stimulation pattern. This is particularly the
case where adjacent points in the grid are separated by a distance
that is less than the differentiation threshold. As illustrated in
FIG. 6B, there is no movement between the first frame and the
second frame, and thus, no new area is stimulated in the transition
from the first frame to the second frame. Additionally, in the
third frame of FIG. 6B, where the shape moves, four of the points
are the same as those previously stimulated while only four points
are stimulating previously unstimulated tissue. Again, this
approach may reduce the energy used to deliver to those previously
stimulated points in order to elicit sensation. The same overall
speed can be achieved while reducing energy input to the
tissue.
[0060] As shown in FIG. 6B simulating movement of a shape may be
accomplished by identifying stimulation points in common among a
plurality of stimulation frames. As illustrated in FIG. 6B, there
are a number of points of stimulation where, when the shape moves,
are again stimulated by trailing points within the shape. This
allows for less energy expended by the system, but also may allow
for a more intense sensation up to a point. In moving a shape it
may become difficult for a user to discern movement if the movement
is too large. Movement may be more easily discerned when smaller
portions of the tissue are dynamically stimulated and allowed to
rest. If large portions of the tissue are constantly stimulated it
may overwhelm the ability of the user to discriminate the changes
at the periphery of the shape.
[0061] Creating shape sensations may be accomplished by any number
of methods. Shapes of sufficiently small sizes or minimal
complexity may be created by fully illuminating the entire shape
all at once for a multiple illuminate source system or in a single
repeated sweep from a single source system. For more complex or
larger shapes, it may be advantageous to use dynamic stimulation.
As the term is used herein, dynamic stimulation may refer to a
stimulation profile that changes through time and represents a
simulated object. Such dynamic changes in stimulation may be
accomplished in any number of ways.
[0062] FIG. 7A illustrate one example of a dynamic shape
stimulation including four stimulation frames. All small circles
represent points of stimulation around the shape. Empty circles 701
represent points of possible stimulation that are not stimulated in
the illustrated frame. Filled circles 702 represent points of
current stimulation. This example moves in time from the frame at
the left to the successive frames at the right. Here a complete
circle is represented by only four points in each frame. The
movement in time of the limited number of points around the
perimeter of the circle allows for the creation of a sensation of
the complete shape with fewer points of stimulation. The spacing
and the timing of movement may be changed to adjust the sensation.
This technique is not limited to the periphery of shapes or any
individual shape. This dynamic movement may be applied to many
different objects of any shape, size or composition.
[0063] FIG. 7B illustrates a shape growing in size over time. An
empty circle (e.g., point 701) represents a possible stimulation
point and the filled circle (e.g., point 702) represents a point of
current stimulation. Time progresses from the left to right. In
this example, a small square appears in the center of the
stimulation field and grows increasingly large in all directions
equally and simultaneously. This process may be repeated or it may
be reversed. The growth of any shape may be accomplished in a
similar manner. Shapes need not always grow symmetrically. This
growth may also be combined with a movement of the shape and the
addition or subtraction of other components of the tactile image as
well. According to one embodiment, a solid square having a
perimeter as shown in the left-most frame may be simulated by
increasing the speed with which a system transitions between the
frames.
[0064] Surface topography may be represented as an array of
stimulation points at various intensities. Sensation intensity may
be represented as the height of this pin at a specified point on
the tissue. In recreating the topography of a surface, one method
is to adjust the relative intensity of each stimulating beam to
represent the relative height of such pins representing the height
of the object at that point.
[0065] FIG. 8 illustrates a representation of a wedge shape where
the individual pins represent the location of stimulating beams
directed at the user's tissue. The relative height of the beam
indicates the relative intensity of the stimulation and the
resultant relative intensity of sensation. In FIG. 8, the pins
aligned with pin 801 is an example of the high side of the wedge,
which a user may experience as pressing more firmly and more deeply
into the tissue in comparison to pins aligned with pin 802, which
represent a low side of the wedge. This technique may be expanded
to create a variety of surface topographies. In various
embodiments, the spacing of the beams may be regular or
irregular.
[0066] FIG. 9 illustrates a functional block diagram of a system
level design for an electromagnetic radiation system to induce
cutaneous sensations. A stimulation controller 900 may provide
laser parameter data, including, but not limited to, amplitude,
pulse width, frequency, duty cycle, and wave form, to a stimulation
system 921. The stimulation controller may acquire input data from,
but not limited to, surface tissue temperature, contact surface
temperature, ambient temperature, calibration data, previous
exposure history, and programmed tactile effect. These input data
may be used by the stimulation controller for determining the
appropriate laser parameters. An output of the stimulation system
921 may be delivered to a beam steering system 928. According to
various embodiments, beam steering system 928 may be embodied using
a fixed array of electromagnetic radiation sources such as VCSEL,
edge emitters, or LEDs that may or may not be embedded as part of
the visual display 921. The output of the stimulation system 921
may be controlled by stimulation controller 900 according to a
stimulation profile. According to various embodiments, the
stimulation profile may correspond to, but are not limited to, a
geometric shape, a topography of a simulated object, a feedback
indicator, and the like.
[0067] Beam steering system 928 may be embodied using a variety of
devices, including, but not limited to, a dual-axis
galvanometer-based scanner, dynamically controlled stacked
polarization gratings, MEMS-based laser scanning mirror, a digital
micromirror devices, acousto-optic beam deflector, liquid crystal
spatial light modulator, and the like. Beam steering system 928 may
direct the beam through a stimulation touch surface, or in some
embodiments, directly to a stimulation area on a user's skin.
Information regarding beam positioning and/or scanning speed may be
collected by beam steering system 928 for use in a closed loop
control system.
[0068] Returning to a discussion of FIG. 9, a position tracking
system 924 may be configured to track the position of tissue being
stimulated or tissue to be stimulated. Position tracking system 924
may be configured to operate in connection with both contact
surface stimulation embodiments and free-space (i.e., non-contact)
stimulation embodiments. In one specific example, a contact surface
stimulation embodiment may comprise a touch screen display.
According to this embodiment, a touch screen digitizer may be used
to track the position of a user's finger on the display. According
to another embodiment, a non-contact stimulation embodiment may
utilize a system to track the position of a user's hand in free
space using, but not limited to, depth cameras and IR sensors and
CCDs, to direct the output of the stimulation system 921 to the
location determined by the position tracking system 924.
[0069] A plurality of sensors 926 may further be coupled to
stimulation controller 900. A variety of types of sensors 926 may
provide inputs and/or feedback to stimulation controller 900. For
example, thermal feedback may be provided by a temperature sensing
instrument, which may be embodied using a variety of devices,
including but not limited to, a thermocouple, thermographic imager,
pyrometric detector. In another example, sensors 926 may include a
perfusion sensor configured to monitor the flow of blood through
tissue being stimulated. In this embodiment, input of the perfusion
sensor may be used to estimate the amount of heat removal due to
blood perfusion. Moreover, a blood flow sensor and a thermal sensor
may be used to determine or estimate thermal conduction and/or heat
capacity of stimulated tissue, according to one embodiment.
[0070] Stimulation controller 900 may be configured to interface
with stimulation system 921, position tracking system 924, and/or
sensors 926 via input/output system 908. Input/output system 908
may be embodied using a variety of technologies, including wired
interfaces (e.g., Universal Serial Bus, IEEE 1394, etc.) or
wireless interfaces (e.g., Bluetooth.RTM., 802.11 wireless
protocols, etc.).
[0071] Stimulation controller 900 may include a processor 906,
which may be configured to execute instructions operable to
implement the functionality and methods disclosed herein. Processor
906 may operate using any number of processing rates and
architectures. Processor 906 may be embodied as a general purpose
integrated circuit, an application specific integrated circuit, a
field-programmable gate array, and/or any other suitable
programmable logic device. Processor 906 may be in communication
with random access memory 902 (RAM), where executable instruction
may be temporarily stored.
[0072] Stimulation controller 900 may also include communications
interface 904 configured to communicate with other devices. In
certain embodiments, the communications interface 904 may
facilitate direct communication with another device or communicate
with another device or multiple devices over a communications
network. According to some embodiments, communications interface
904 may be embodied as an Ethernet port.
[0073] A bus 910 may provide communication among RAM 902,
communications interface 904, processor 906, input/output ports
908, and a non-volatile computer-readable storage medium 911.
Computer-readable storage medium 911 may be the repository of
various software modules configured to perform any of the methods
described herein. A stimulation control module 918 may be
configured to coordinate the operation of the plurality modules,
whose specific functions are described below, and to generate a
stimulation profile.
[0074] Stimulation profile authoring module 919 may allow access to
a library of predefined stimulation profiles. For example, a
programmer may intend to convey to the end user the physical
sensation of touching a key. The shape and the physical dimensions
of the key may be inputs to the stimulation profile authoring
module 919. The stimulation profile authoring module 919 may
translate the desired physical shape into a stimulation profile to
feed to a stimulation system. Stimulation controller 900 may make
adjustments to these parameters based on, but not limited to,
tissue temperature, movement speed of the tissue of the object,
previous stimulation, and other variables in controlling the output
of stimulation system 921. Stimulation profile authoring module 919
may allow access to individual stimulation parameters. In some
embodiments, stimulation profile authoring module 919 may check to
make sure that the stimulation profile does not exceed specified
thresholds for energy deposition and energy deposition rates. In
another embodiment, stimulation profile authoring module 919 may
allow the combination or blending of the one or more predesigned
library of sensations. In one embodiment, stimulation profile
authoring module 919 may accept graphic or CAD files created by a
user. Using CAD files, stimulation profile authoring module 919 may
translate the desired shapes into appropriate stimulation profiles,
including, but not limited to, stimulation spacing, amplitude,
pulse width, frequency, sweep speed, waveform, area, duty cycle,
depth or intensity of sensation; all to be delivered to the tissue
of the end user.
[0075] A tactile application module 912 may be configured to
interact with any number of programs and/or devices and to
coordinate operation of the stimulation controller 900 with such
programs and/or devices. According to various embodiments, the
tactile applications may include, but are not limited to,
telepresence medicine, compact electronic Braille displays, virtual
product online shopping, representing simulated and physical
objects and drawings in computer generated images and computer
aided drafting (CAD), for touch screen feedback, control feedback,
and/or entertainment and gaming devices.
[0076] An angle adjustment module 913 may be configured to modify a
stimulation profile to account for variation in a sensation that
may be attributable to areas having a curvature or a corner. As
discussed above, the greater proximity of stimulation points in an
area of curvature may cause the sensation to become more intense if
the energy imparted at each point of stimulation remains constant.
In one embodiment, the angle adjustment module 913 may be
configured to operate in a manner consistent with the embodiments
illustrated in FIGS. 2A-2D and described in detail herein.
[0077] Returning to a discussion of FIG. 9, a dynamic stimulation
module 915 may be configured to generate a dynamic stimulation
corresponding to a simulated object. A dynamic stimulation may
refer to a stimulation profile that changes through time and
represents a simulated object. Such dynamic changes in stimulation
may be accomplished in any number of ways. FIGS. 5A and 5B provide
examples of some dynamic stimulations, which may be implemented by
dynamic stimulation module 915 according to certain
embodiments.
[0078] Returning to a discussion of FIG. 9, frequency adjustment
module 916 may be configured to achieve a steady frequency of
stimulation of each of a plurality of points in a moving array of
stimuli. The frequency of intermittent stimulation at a single
point affects the total energy delivered and the intensity of the
sensation. Accordingly, frequency adjustment module 916 may be
configured to adjust an order in which a plurality of stimulation
points to create a uniform frequency of stimulation. FIG. 3
provides an example of a modification of a stimulation protocol to
create a uniform frequency of stimulation that may be implemented,
according to certain embodiments, by frequency adjustment module
916.
[0079] Topography module 917 may be configured to alter the output
of stimulation system 921 to create a representation of a
topography of a simulated object. According to one embodiment,
topography module 917 may be configured to adjust the relative
intensity of each of a plurality of stimulating beam to represent
the object at that point. According to various embodiments, a
combination of sensations may be combined to convey information
about the topography of an object, such as height, smoothness or
roughness, sharpness or dullness, hardness or softness, and the
like.
[0080] FIG. 10A illustrates a conceptual representation of a system
configured to create variable cutaneous sensations associated with
stationary tissue consistent with embodiments of the present
disclosure. As illustrated, a single plane of the scenario of a
variable surface being delivered through a transmissive surface
1032 to a finger 1031. 1033 represent the individual beams of
illumination. A stimulation profile 1034 represents the varying
intensities of each of the beams.
[0081] FIG. 10B illustrates that over time, the stimulation profile
1034 shown in FIG. 10A and representing a topography of a simulated
object, changes beneath the finger. In the illustrated example, the
varying stimulation profiles are arranged from top to bottom. The
topography of the simulated surface progresses from a variable, or
rough, surface to a smooth surface with an abrupt edge. A variety
of surface topographies could be represented within the bounds of
intensities available. Other parameters that can be adjusted to
represent surface topography include, but are not limited to, pulse
width, amplitude, frequency, duty cycle, spot size, spot spacing,
and wave form.
[0082] FIG. 11A illustrates a conceptual representation of a system
configured to create a cutaneous sensation by varying a stimulation
amplitude at a fixed location while a finger 1101 moves across the
fixed location consistent with embodiments of the present
disclosure. A system configured to stimulate moving tissue may
monitor the position, acceleration, and speed of the tissue (e.g.,
finger 1101) in relation to the simulated object. When the finger
1101 is positioned away from the simulated object the system may
provide no stimulation. When the finger 1101 is placed over any
portion of the field of the simulated object, the appropriate
amount of stimulation may be imparted. FIG. 11A represents a single
point of stimulation 1102 maintained in a stationary place while a
finger 1101 moves across it. The acceleration and speed at which
the finger moves may be variables based on which the stimulation
system determines an amount of energy to impart to the tissue to
create a given intensity of sensation and to minimize sensation
onset.
[0083] FIGS. 11B-11D illustrate three stimulation profiles that may
represent a topography of a simulated object based on acceleration
and speed of the finger 1101 as it moves across the point of
stimulation 1102. In FIG. 11B, the finger 1101 is moving relatively
quickly. Accordingly, each stimulation pulse of stimulation profile
1106 is separated by a relatively large distance. In other words,
each time the finger is stimulated, because of the relatively high
speed, a new portion of the finger is stimulated which has been
previously unstimulated. The stimulation profile 1106 may have a
relatively high amplitude 1104, and thus may be able to provide
sufficient energy to meet and exceed a sensation threshold 1105.
The sensation threshold 1105 represents the minimum energy level
necessary to maintain sensation on a portion of the finger which is
stationary and has, therefore, been irradiated previously to the
point of sensation.
[0084] FIG. 11C, illustrates a situation in which the finger 1101
is moving more slowly than in FIG. 11B, and accordingly, the
stimulation profile 1107 has a lower amplitude in comparison to
FIG. 11B. The amplitude illustrated in FIG. 11B exceeds the
sensation threshold 1105 but is lower than that necessary for
previously unilluminated tissue. As discussed above, previously
stimulated tissue may heat surrounding tissue and make such tissue
more receptive to stimulation.
[0085] FIG. 11D illustrates a situation in which the FIG. 1101 is
moving more slowly than in FIG. 11C, and accordingly, the
stimulation profile 1108 has a lower amplitude in comparison to
FIG. 11C. The amplitude illustrated in FIG. 11C is approximately
equal to the sensation threshold 1105. Again, as discussed above,
because of the heating associated with stimulation of the tissue
and adjacent regions during period of stimulation, the reduced
energy may be sufficient to elicit a sensation that is
approximately equal to the sensations imparted as a result of a
stimulation profile.
[0086] FIGS. 11E-11G further illustrate that an amplitude of a
stimulation profile may vary as a result of a topography of a
simulated object. In FIGS. 11E-11G, simulated object is a
stationary simulated plateau, represented by reference no 1123. The
simulated object may be created by illumination of the finger 1121
with multiple light beams 1124 at variable energies 1125 only when
the finger 1121 is within the field 1126 of the simulated object.
The finger 1121 is moving sequentially from left to right at a
constant speed. FIG. 11E illustrates the finger 1121 initially
encountering the edge of the plateau. When the finger enters the
field 1126 of the simulated plateau, it may initially encounter the
edge of the plateau. The stimulation system may create the
sensation of an abrupt edge and a constant height of the simulated
object by illuminating the finger 1121 at a higher level than would
be necessary for maintenance of sensation of previously stimulated
tissue. Only the portion of the finger that is both contacting the
surface and in the field of the simulated object is
illuminated.
[0087] FIG. 11F illustrates that as time progresses, the energy
level of stimulation may drop to the minimum necessary for
maintenance of the sensation at the level of the plateau. In the
middle panel, the finger is entirely within the field of the
plateau, yet remains in motion. The entire contact area of the
finger may be illuminated at the maintenance level of the
plateau.
[0088] FIG. 11G illustrates the stimulation profile as the finger
exits the field 1126 and passes from the top of the simulated
plateau to the opposite edge of the simulated plateau. Only the
portion of the finger remaining in the plateau area may continue to
be stimulated. There may also be edge effects for the trailing edge
as the finger leaves the plateau area which makes for a more
distinct edge felt tactilely.
[0089] The example illustrated in FIGS. 11E-11G in which the finger
1121 moves across a simulated object at a constant speed is only
one of several possible cases. There are times when the user will
begin to move more quickly or more slowly over an edge or the body
of such a simulated object. According to various embodiments
consistent with the present disclosure, a controller of a
stimulation system may compensate for the speed of movement and
acceleration by changing the amount of energy imparted to the
finger. For example, in the case of increased speed starting in the
middle of an object larger than the finger pad, sustained sensation
may require no change in energy delivery, but the position of
delivery may move more quickly to match the finger position. In the
case of increased speed on the initial edge of encounter with an
object, the energy delivered may need to increase and would do so
in proportion to the speed as it would be necessary to bring on
sensation to new portions of the finger pad more quickly.
[0090] FIG. 12A illustrates a representation of sharp sensation
consistent with embodiments of the present disclosure, while FIG.
12B illustrates a dull sensation consistent with embodiments of the
present disclosure. In FIGS. 12A and 12B, an area of tissue 1201
may include a plurality of stimulation sites 1202. According to
some embodiments the plurality of stimulation sites 1202 may be
mechanoreceptor fields or thermal receptive fields.
[0091] Mechanoreceptive fields, as the term is used herein, are the
basic unit of sensation. In other words, the minimum area of
sensation that can be distinguished by sensation uniquely from a
similar area adjacent based on mechanical stimuli. This is similar
to the concept of two-point discrimination in mechanical testing.
The idea is that there is a distance beyond which two points of
sensation are distinctly felt and below which two points of
stimulation are experienced as one point of sensation. In the case
of light induced sensation, a a photoreceptive equivalent of a
mechanoreceptor field may have a radius of one half the distance
from one center of illumination to the next when these two beams
are at the minimum distance to produce two points of distinct
sensation. Mechanoreceptive fields may have any number of different
mechanoreceptor cells and nerve endings contained therein. The
distinction of a field is not based on anatomy, rather experimental
physiology. The field is sized by sensation produced and not the
mechanism. These fields vary in size depending on the location on
the skin, much like the two-point discrimination determined by
mechanical testing. Certainly the density of physiologic sensors
plays a role in this, but it is not determined how many receptors
are actually contained in any given mechanoreceptive field for
purposes of the present disclosure. FIGS. 12A and 12B illustrate a
conceptual photoreceptive equivalent to the mechanoreceptive
field.
[0092] In FIG. 12A, a light beam 1203 incident on the skin may
activate one of the plurality of stimulation sites 1202
corresponding to a mechanoreceptor field to induce the sensation of
mechanical activation or a photoreceptive equivalent. An area of
stimulation induced by a light beam 1203 may be represented as a
series of concentric rings 1204. In the illustrated embodiment, a
greater number of rings may indicate a higher activation and thus,
a more intense sensation. FIG. 12A shows only a single point of
stimulation with high intensity. This stimulation profile may be
experienced as a sharp point.
[0093] FIG. 12B illustrates stimulation at a plurality of
stimulation points, with the most intense stimulation in the center
and reduced stimulation moving away from the center. The
illustrated stimulation profile may create a graded sensation from
the most intense in the center to minimally intense near the edge
of the sensation. This stimulation profile may correspond to a
sensation of a dull object. Sensations, such as sharp and dull, may
be created by the contour of the edges, whether there is a large
difference in activation of adjacent mechanoreceptors. Light
induced stimulation may provide tight control over the area of
sensation. Dramatic changes in sensation intensity can be created
in small areas with the ability to create the tactile illusion of a
dramatically sharp edge.
[0094] FIG. 13 illustrates various stimulation profiles 1301-1303
that rapidly induce a sensation and maintain a constant level of
sensation over time consistent with embodiments of the present
disclosure. Onset of a tactile sensation may be dictated by the
light tissue interaction and different onset effects can be
created. A near immediate onset of sensation may be achieved by a
stimulation protocols that impart a high energy to the tissue in a
short time. After this onset, if a sustained sensation is desired a
number of different protocols can be used. Stimulation profile 1301
illustrates a scenario in which the initial pulses are of
sufficiently high energy to quickly elicit sensation but fall off
in energy as less energy is required to sustain sensation.
Stimulation profile 1302 illustrates a scenario in which a single
pulse may elicits sensation and then allows the tissue to rest for
a short time before delivering a sustained train of stimulation
pulses to maintain a constant sensation. Stimulation profile 1303
illustrates a scenario in which a strong initial pulse is followed
by pulses of reduced intensity that reach an equilibrium after a
period of time. Stimulation profiles 1301-1303 are only examples of
stimulation profiles that may induce rapid onset of a sensation
that may be indefinitely maintained.
[0095] FIG. 14A illustrates an approximately circular pattern 1403
created by a stimulating beam 1402 when the beam incidence is
normal to the tissue 1401. In contrast, as illustrated in FIG. 14B,
an elliptical pattern 1404 is created by the stimulating beam 1402
when the stimulating beam 1402 is at a high angle of incidence to
the tissue 1401. When the beam incidence is normal to the tissue,
as illustrated in FIG. 14A, the resultant illumination spot is
minimized; however, when the angle of incidence increases, so does
the size of the illumination spot. This may result in an increased
amount of reflection at the surface as well as a decrease in the
energy density. A stimulation system may compensate for such
changes by increasing or decreasing the energy delivered to the
tissue to elicit the desired sensation intensity.
[0096] FIG. 15A illustrates a conceptual representation for
delivering stimulation profile 1501 to a user to convey information
regarding a surface topography of a simulated object using movement
of an stimulation area or a series of stimulation areas generated
by an electromagnetic radiation system. The speed in which the
spot(s) moves is also perceptible to the user. In one embodiment,
the scanning speed in which the illumination spot(s) move relative
to the tissue may vary to render the surface topography desired. In
one embodiment, the scanning speed of the illumination spot(s) may
increase by a calculated amount to represent a raised or "high"
point at a certain location along the surface. Conversely, a slower
scanning speed may be delivered to the user by some calculated
amount for depressions or "low" points. In another possible
embodiment the surface topography can be used to represent how the
speed of the illumination spot(s) changes with either position or
time as shown in FIG. 15A.
[0097] FIG. 15B illustrates that an inverse relationship, in
comparison to FIG. 15A, between scanning speed of the illumination
spot(s) and surface topography may also be used to convey
information regarding the topography of a simulated object
according to certain embodiments consistent with the present
disclosure. In such an embodiment, the raised surface may be
represented by slower scanning speeds and the depressions
represented by faster scanning speeds as shown by stimulation
profile 1503. There may be a minimum scanning speed needed to
differentiate it from a static illumination spot(s). Similarly,
there may be a maximum scanning speed above which sensations are
detected as part of a larger stationary object rather than a
smaller moving object. In another embodiment, other parameters
including, but not limited to, number of illumination spots,
illumination spot/path spacing, amplitude, pulse width, spot size,
frequency, duty cycle, and waveform, may also be varied according
to the surface topography. Variation of sensation movement may, in
certain embodiments, be an inferred representation of topography
rather than a true physical depiction.
[0098] In addition to variation in the scanning speed of an
illumination spot, a variety of other parameters associated with a
stimulation system may be modified to provide information regarding
a topography or surface of a simulated object to a user. For
example, a system may vary the number of illumination spots,
illumination spot or path spacing, amplitude, pulse width, spot
size, frequency, duty cycle, and waveform to provide information to
a user regarding a simulated object.
[0099] While specific embodiments and applications of the
disclosure have been illustrated and described, the disclosure is
not limited to the precise configurations and components disclosed
herein. Accordingly, many changes may be made to the details of the
above-described embodiments without departing from the underlying
principles of this disclosure. The scope of the present invention
should, therefore, be determined only by the following claims.
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