U.S. patent application number 13/460142 was filed with the patent office on 2012-08-23 for apparatus and method for a folded optical element waveguide for use with light based touch screens.
This patent application is currently assigned to POA SANA LIQUIDATING TRUST. Invention is credited to Gerard Dirk Smits.
Application Number | 20120212456 13/460142 |
Document ID | / |
Family ID | 35513361 |
Filed Date | 2012-08-23 |
United States Patent
Application |
20120212456 |
Kind Code |
A1 |
Smits; Gerard Dirk |
August 23, 2012 |
APPARATUS AND METHOD FOR A FOLDED OPTICAL ELEMENT WAVEGUIDE FOR USE
WITH LIGHT BASED TOUCH SCREENS
Abstract
A folded optical element waveguide that allows a minimum width
bezel to be used around the perimeter of a light-based touch screen
display. The apparatus and method includes a touch screen and a
waveguide substrate provided adjacent the touch screen. The
waveguide substrate includes a plurality of waveguides and a
plurality of optical elements provided adjacent the touch screen.
The waveguides include an internally reflective surface to reflect
light perpendicular to the surface of the touch screen. The
emitting and detecting waveguides are thus folded and provided
around the side edges of the display. As a result, the width of the
bezel around the display can be minimized.
Inventors: |
Smits; Gerard Dirk; (Los
Gatos, CA) |
Assignee: |
POA SANA LIQUIDATING TRUST
Mountain View
CA
|
Family ID: |
35513361 |
Appl. No.: |
13/460142 |
Filed: |
April 30, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10923550 |
Aug 20, 2004 |
8184108 |
|
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13460142 |
|
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60584728 |
Jun 30, 2004 |
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Current U.S.
Class: |
345/175 |
Current CPC
Class: |
G02B 6/0018 20130101;
G06F 3/0421 20130101 |
Class at
Publication: |
345/175 |
International
Class: |
G06F 3/042 20060101
G06F003/042 |
Claims
1. An apparatus, comprising; a touch screen having a display
surface; a bezel supporting therein the touch screen, the bezel
having a sidewall that is not coplanar with the display surface;
said bezel sidewall comprising an array of waveguides associated
with a reflector that one of: directs light from one of said
waveguides adjacent to said display surface; or receives light from
adjacent to said display surface and directs it into a waveguide;
the array of waveguides comprising, a first set of waveguides
arranged on the a first sidewall of the bezel; a second set of
waveguides arranged on the a second sidewall of the bezel; and
wherein the first and second sidewalls are arranged at opposite
sides of the touch screen.
2. The apparatus recited in claim 1 wherein the reflector is
integral to an associated waveguide.
3. The apparatus recited in claim 2 wherein the integral reflector
comprises a mirrored surface at a bend in the associated
waveguide.
4. The apparatus recited in claim 1 wherein the reflector is
distinct from and located proximal to an associated waveguide.
5. The apparatus recited in claim 1 wherein, the first set of
waveguides is associated with a light source that is projected
through the first set of waveguides; the second set of waveguides
is associated with a light detector that detects light received by
the second set of waveguides; and light projected through the first
set of waveguides and received by the second set of waveguides
forms an interruptable light pattern proximal to the display
surface of the touch screen, the pattern formed such that the
location of interruptions to the light pattern can be
determined.
6. The apparatus recited in claim 5 wherein the interruptable light
pattern comprises a grid of light extending over the display
surface of the touch screen.
7. The apparatus recited in claim 5 wherein the interruptable light
pattern comprises a contiguous lamina of light extending over the
display surface of the touch screen.
8. The apparatus recited in claim 7 wherein the contiguous lamina
of light is in the range of about 1 millimeter to 4 millimeters
thick.
9. The apparatus recited in claim 5 wherein, a third set of
waveguides arranged on a third sidewall is associated with a light
source that is projected through the first set of waveguides; the
second set of waveguides is associated with a light detector that
detects light received by the second set of waveguides; and light
projected through the first set of waveguides and received by the
second set of waveguides forms an interruptable light pattern
proximal to the display surface of the touch screen, the pattern
formed such that the location of interruptions to the light pattern
can be determined.
10. The apparatus recited in claim 1 wherein an outer portion of
the sidewall supports the array of waveguides.
11. The apparatus recited in claim 1 wherein the reflector
comprises a light reflecting means for one of: directing light from
one of said waveguides adjacent to said display surface; or
receiving light from adjacent to said display surface and directing
it into one of said waveguides.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of and claims priority to
co-pending U.S. patent application Ser. No. 10/923,550 filed on
Aug. 20, 2004, entitled "Apparatus and Method for a Folded Optical
Element Waveguide for Use with Light Based Touch Screens," which
claims priority to U.S. Provisional Patent Application No.
60/584,728, filed Jun. 30, 2004, all of which are incorporated
herein by reference for all purposes.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally light based to touch
screen displays, and more particularly, to an apparatus and method
for a folded optical element waveguide that allows a minimum width
bezel to be used around the perimeter of the touch screen
display.
[0004] 2. Description of the Related Art
[0005] User input devices for data processing systems can take many
forms. Two types of relevance are touch screens and pen-based
screens. With either a touch screen or a pen-based screen, a user
may input data by touching the display screen with either a finger
or an input device such as a stylus or pen.
[0006] One conventional approach for providing a touch or pen-based
input system is to overlay a resistive or capacitive film over the
display screen. This approach has a number of problems. Foremost,
the film causes the display to appear dim and obscures viewing of
the underlying display. To compensate, the intensity of the display
screen is often increased. However, in the case of most portable
devices, such as cell phones, personal digital assistants, and
laptop computers, high intensity screens are usually not provided.
If they are provided, the added intensity requires additional
power, reducing the life of the battery of the device. The films
are also easily damaged. These films are therefore not ideal for
use with pen or stylus input devices. The motion of the pen or
stylus may damage or tear the thin film. This is particularly true
in situations where the user is writing with a significant amount
of force. In addition, the cost of the film scales dramatically
with the size of the screen. With large screens, the cost is
therefore typically prohibitive.
[0007] Another approach to providing touch or pen-based input
systems is to use an array of source Light Emitting Diodes (LEDs)
along two adjacent X-Y sides of an input display and a reciprocal
array of corresponding photodiodes along the opposite two adjacent
X-Y sides of the input display. Each LED generates a light beam
directed to the reciprocal photodiode. When the user touches the
display, with either a finger or pen, the interruptions in the
light beams are detected by the corresponding X and Y photodiodes
on the opposite side of the display. The data input is thus
determined by calculating the coordinates of the interruptions as
detected by the X and Y photodiodes. This type of data input
display, however, also has a number of problems. A large number of
LEDs and photodiodes are required for a typical data input display.
The position of the LEDs and the reciprocal photodiodes also need
to be aligned. The relatively large number of LEDs and photodiodes,
and the need for precise alignment, make such displays complex,
expensive, and difficult to manufacture.
[0008] Yet another approach involves the use of polymer waveguides
to both generate and receive beams of light from a single light
source to a single array detector. These systems tend to be
complicated and expensive and require alignment between the
transmit and receive waveguides and the optical elements and the
waveguides. The waveguides are usually made using a lithographic
process that can be expensive or difficult to source. In addition,
the waveguides are typically flat. As a consequence, the bezel
around the display is relatively wide. See for example U.S. Pat.
No. 5,914,709.
[0009] Accordingly, there is a need for a folded optical element
waveguide that allows a minimum width bezel to be used around the
perimeter of a touch screen display.
SUMMARY OF THE INVENTION
[0010] The present invention relates to an apparatus and method for
a folded optical element waveguide that allows a minimum width
bezel to be used around the perimeter of a light-based touch screen
display. The apparatus and method includes a touch screen and a
waveguide substrate provided adjacent the touch screen. The
waveguide substrate includes a plurality of waveguides and a
plurality of optical elements provided adjacent the touch screen.
The waveguides include an internally reflective surface to reflect
light perpendicular to the surface of the touch screen. The
emitting and detecting waveguides are thus folded and provided
around the side edges of the display. As a result, the width of the
bezel around the display can be minimized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention, together with further advantages thereof, may
best be understood by reference to the following description taken
in conjunction with the accompanying drawings in which:
[0012] FIG. 1 is a touch screen display device.
[0013] FIG. 2 is a bezel used around the perimeter of the touch
screen display device.
[0014] FIG. 3 is a cross section of the bezel used around the
perimeter of the touch screen device.
[0015] FIG. 4 is a perspective view of a folded waveguide substrate
and bezel used around the touch screen display device according to
the present invention.
[0016] FIG. 5 is a side view of the folded waveguide and bezel of
the present invention.
[0017] FIG. 6A is a cross section view of the folded waveguide and
bezel of the present invention.
[0018] FIGS. 6B and 6C are enlarged diagrams of folded waveguides
according to the present invention.
[0019] FIG. 7 is another touch screen device that can be used with
the folded waveguide and bezel of the present invention.
[0020] In the figures, like reference numbers refer to like
components and elements.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Referring to FIG. 1, a touch screen data input device
according to one embodiment of the invention is shown. The data
input device 10 defines a continuous sheet or "lamina" 12 of light
in the free space adjacent a touch screen 14. The lamina 12 of
light is created by X and Y input light sources 16 and 18
respectively. An optical position detection device 20, optically
coupled to the lamina of light, is provided to detect data entries
to the input device by determining the location of interrupts in
the lamina 12 caused when data is entered to the input device. The
optical position detection device 20 includes an X receive array
22, a Y receive array 24, and a processor 26. The X and Y input
light sources 16 and 18 and the X and Y receive arrays 22 and 24
are clad in a bezel 28 that surrounds the lamina 12 and the touch
screen 14.
[0022] During operation, a user makes a data entry to the device 10
by touching the screen 14 using an input device, such as a pen,
stylus or finger. During the act of touching the screen with the
input device, the lamina 12 of light in the free space adjacent the
screen is interrupted. The X receive array 22 and Y receive array
24 of the optical position detection device 20 detect the
interrupt. Based on the X and Y coordinates of the interrupt, the
processor 26 determines the data entry to the device 10. For more
information on the data entry device 10, see co-pending, U.S.
application Ser. No. 10/817,564, entitled Apparatus and Method for
a Data Input Device Using a Light Lamina Screen and an Optical
Position Digitizer, filed Apr. 1, 2004, and incorporated by
reference herein for all purposes.
[0023] Referring to FIG. 2, an enlarged view of the bezel 28 is
shown. The bezel 28 has four sides, the X and Y light input arrays
16, 18 and the X and Y light receive arrays 20, 22. A plurality of
optical elements 30 are provided along the inner periphery of the
bezel 28. A plurality of waveguides 32 are optically coupled to the
plurality of optical elements 30 respectively. A first subset of
the waveguides 32a extend between a light source 34, such as a
laser, and the optical elements 30 of the light input arrays 16, 18
respectively. A second subset of the waveguides 32b extend between
an imaging device 36, such as a charge coupled device or MOS
imaging chip, and the optical elements 30 of the light receive
arrays 20, 22 respectively. The two subsets of waveguides 32a and
32b each form what is sometimes referred to as a "waveguide
highway". The pitch of the individual waveguides 32 along the
highway may vary but typically is 1.6 microns. In various
embodiments of the invention, the optical elements 30 are
vertically collimated lenses.
[0024] Referring to FIG. 3, a cross section of the data input
device 10 is shown. The cross section shows the lamina 12 created
over the touch screen 14. In various embodiments, the lamina 12 may
range in thickness from 1 to 4 millimeters. The cross section shows
two optical elements 30 positioned on opposite sides of the lamina
12. As described above, one of the optical elements 30 (e.g., 30a)
is used for light input to create the lamina 12 and the other
(e.g., 30b) is used to detect data entries (i.e., interrupts in the
lamina). Waveguides 32a and 32b are optically coupled to the two
optical elements 30a and 30b respectively. The optical elements
30a, 30b and the waveguides 32a, 32b are integral or clad in the
bezel 28.
[0025] With light based input devises such as that illustrated in
FIG. 1, a high degree of resolution is typically desired. To
achieve the desired finer resolution, a larger number of relatively
small optical elements 30 are required around the periphery of the
bezel 28. Since each optical element 30 has a corresponding
waveguide 32, the waveguide highways 32a and 32b can become
relatively wide. As a result, the width of bezel 28 also becomes
very wide. With portable devices, such as cell phones, personal
digital assistants, or laptops, a wide bezel surrounding the touch
display is less than desirable.
[0026] Referring to FIG. 4, a perspective view of a folded
waveguide substrate 40 according to the present invention is shown.
The folded waveguide substrate 40 includes a plurality of optical
elements 30 embedded or integral in a bezel 41 surrounding the
periphery of a touch screen 14. The substrate 40 is considered
"folded" because the individual waveguides 32 bend from the top
surface to a side or vertical surface of the substrate 40. Within
each waveguide 32, a forty-five degree cut surface creates an
internally reflective mirror, creating an orthogonal light path
between the top and a vertical side surface of the substrate 40.
Thus on the transmit side, light travels from a light source (not
shown), down the individual waveguides 32a along one or more side
surfaces of the substrate 40. Each waveguide 32 eventually bends
upward along the vertical axis of the substrate 40. At the fold,
the mirrored surface internally reflects the light from the
vertical to the horizontal axis, and then through the corresponding
optical element 30. On the receive side, light enters through the
plurality the optical elements 30, is internally reflected off the
mirrored surfaces, and then travels along the corresponding
waveguides 42 along the side surface or surfaces of substrate 40 to
an imaging device (not shown).
[0027] Referring to FIG. 5, a view of one of the sides of substrate
40 is shown. In this view, the optical elements 30 are shown along
the top perimeter of the substrate 40 and the various highways of
waveguides 32 are shown traveling along the side of the substrate
40. In the location of each optical element 30, the corresponding
waveguide 32 bends upward along the vertical axis defined by the
side of the substrate 40. The vertical axis is perpendicular to the
horizontal axis of the display 14.
[0028] Referring to FIG. 6, a cross section of a folded optical
element waveguide substrate 40 is shown. The waveguide substrate 40
is positioned adjacent the touch screen 14. In the cross section,
two optical elements 30 are shown on opposite sides of the screen
14. As is illustrated, each optical element 30 includes an
internally reflective surface 44. The reflective surface 44 creates
a minor internal to the optical element that allows light to
reflect from the vertical axis to the horizontal axis, or
vice-versa, depending if the waveguide is used for emitting or
detecting. The mirrored surface 44 creates a ninety degree
deflection of the light beams perpendicular to the display surface
of the touch screen 14. Consequently, the waveguides 32 can be
provided on the side/surfaces of the substrate 40. The width of the
bezel 41 surrounding the touch screen 14 is therefore
minimized.
[0029] Referring to FIG. 6B, one embodiment of an optical element
30 is shown. In this embodiment, the optical element has a curved
lens surface 45 that is configured to focus received light rays
onto the internally reflective surface 44. The internally reflected
surface 44 directs the reflected light to a single point located in
the vicinity of the waveguide 32. In this manner, light received
from the lamina 12 through the curved lens in one axis is directed
to the waveguide 32 in a perpendicular axis and vice versa.
[0030] Referring to FIG. 6C, another embodiment of an optical
element 30 is shown. In this embodiment, the optical element 30 has
a flat lens surface 46 that is configured to focus received light
rays onto a curved internally reflective surface 44. The internally
reflected surface 44 directs the reflected light to a single point
located in the vicinity of the waveguide 32. In this manner, light
received from the lamina 12 through the flat lens 46 in one axis is
directed to the waveguide 32 in a perpendicular axis and vice
versa.
[0031] Referring to FIG. 7, another touch screen display device is
shown. The data input device 70 defines a grid of light 32 in the
free space adjacent to a touch screen 14. The grid of light 72 is
created by an X and Y input light sources 16 and 18 respectively.
An optical position detection device 20, optically coupled to the
grid of light 72 of light, is provided to detect data entries to
the input device by determining the location of interrupts in the
grid of light 72 caused when data is entered to the input device.
The optical position detection device 20 includes an X receive
array 22, a Y receive array 24, and a processor 26. During
operation, a user makes a data entry to the device 10 by touching
the screen 14 using an input device, such as stylus, pen or a
finger. During the act of touching the screen with the input
device, the grid of light 32 in the free space adjacent the screen
is interrupted. The X receive array 22 and Y receive array 24 of
the optical position detection device 20 detect the X and Y
coordinates of the interrupt. Based on the coordinates, the
processor 26 determines the data entry to the device 10. In an
alternative embodiment of the invention, the folded substrate 40
with the minimized bezel 41 as described above with regard to FIGS.
4-6 can be used with the light based grid input device 70.
[0032] Although the foregoing invention has been described in some
detail for purposes of clarity of understanding, it will be
apparent that certain changes and modifications may be practiced
within the scope of the appended claims. Therefore, the described
embodiments should be taken as illustrative and not restrictive,
and the invention should not be limited to the details given herein
but should be defined by the following claims and their full scope
of equivalents.
* * * * *