Multi-user touch screen
First Claim
Patent Images
1. A method of detecting touch on a touch-screen surface, comprising:
- providing a transparent slab, the transparent slab comprising a top surface and a bottom surface, and at least one side edge;
injecting light into the transparent slab by placing at least one light source on the at least one side edge of the transparent slab, the at least one light source being placed so as to cause light injected in the transparent slab to be totally internally reflected in the transparent slab so that the top surface and the bottom surface of the transparent slab emit a minimum amount of light;
receiving touch on the transparent slab with a body part of the user, wherein the touch of the user on the transparent slab disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the body part of the user; and
capturing with a camera the portion of the light refracted into the body part of the user due to the touch of the body part on the transparent slab,wherein the camera is a shutter camera, the method further comprising;
turning the at least one light source on;
capturing a first video frame with the shutter camera so as to capture ambient light and the portion of the light refracted into the body part of the user;
turning the at least one light source off;
capturing a second video frame with the shutter camera so as to capture the ambient light; and
subtracting the second video frame from the first video frame to create a third video frame that excludes ambient light, wherein the third video frame includes a signal representative of the touch of the user on the transparent slab.
1 Assignment
0 Petitions
Accused Products
Abstract
A multi-user touch-responsive viewing screen is described which uses frustrated total internal reflection in a slab of transparent material to illuminate the contact point between the slab and a finger or other object substantially matching the slab'"'"'s index of refraction. Light, coupled upon touch, can be detected with a video camera, and used to determine both the position and pressure of the touch. Multiple touches can be accommodated and each touch accurately located. Projected images can be applied to the slab and a diffuser to construct an interactive touch screen.
110 Citations
47 Claims
-
1. A method of detecting touch on a touch-screen surface, comprising:
-
providing a transparent slab, the transparent slab comprising a top surface and a bottom surface, and at least one side edge; injecting light into the transparent slab by placing at least one light source on the at least one side edge of the transparent slab, the at least one light source being placed so as to cause light injected in the transparent slab to be totally internally reflected in the transparent slab so that the top surface and the bottom surface of the transparent slab emit a minimum amount of light; receiving touch on the transparent slab with a body part of the user, wherein the touch of the user on the transparent slab disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the body part of the user; and
capturing with a camera the portion of the light refracted into the body part of the user due to the touch of the body part on the transparent slab,wherein the camera is a shutter camera, the method further comprising; turning the at least one light source on; capturing a first video frame with the shutter camera so as to capture ambient light and the portion of the light refracted into the body part of the user; turning the at least one light source off; capturing a second video frame with the shutter camera so as to capture the ambient light; and subtracting the second video frame from the first video frame to create a third video frame that excludes ambient light, wherein the third video frame includes a signal representative of the touch of the user on the transparent slab. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
-
-
29. A method of detecting touch on a touch-screen surface with an improved signal-to-noise ratio, comprising:
-
providing a transparent slab, the transparent slab comprising a top surface and a bottom surface, and at least one side edge; injecting light into the transparent slab by placing at least one light source on the at least one side edge of the transparent slab, the at least one light source being placed so as to cause light injected in the transparent slab to be totally internally reflected in the transparent slab;
receiving touch on the transparent slab with a body part of the user, wherein the touch of the user on the transparent slab disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the body part of the user; and
turning the at least one light source on;capturing a first video frame with a first shutter camera so as to capture ambient light and the portion of the light refracted into the body part of the user; turning the at least one light source off; capturing a second video frame with a second shutter camera so as to capture the ambient light; and subtracting the second video frame from the first video frame to create a third video frame that excludes ambient light, wherein the third video frame includes a signal representative of the touch of the user on the transparent slab. - View Dependent Claims (30, 31, 32, 33, 34)
-
-
35. A system to detect touch on a touch-screen surface, comprising:
-
a transparent slab, the transparent slab comprising a top and a bottom surface, and at least one side edge; at least one light source placed to inject light in the at least one side edge of the transparent slab, wherein the light injected in the transparent slab is totally internally reflected in the transparent slab so that the top surface and the bottom surface of the transparent slab emit a minimum amount of light; and a camera configured to capture at least one spot of light in the transparent slab, wherein the at least spot of light is created by a user touching the transparent slab with a body part, wherein the touch of the user on the transparent slab disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the body part of the user, wherein the camera is a shutter camera configured to capture a first video frame comprising a spot of light in the transparent slab when the at least one light source is turned on, wherein the camera is further configured to capture a second video frame with the shutter camera so as to capture the ambient light when the at least one light source is turned off, the system further comprising; a subtractor that subtracts the second video frame from the first video frame to create a third video frame that excludes ambient light, wherein the third video frame includes a signal representative of the touch of the user on the transparent slab. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44)
-
-
45. A system to detect touch on a touch-screen surface, comprising:
-
a transparent slab, the transparent slab comprising a top and a bottom surface, and at least one side edge; at least one light source placed to inject light in the at least one side edge of the transparent slab, wherein the light injected in the transparent slab is totally internally reflected in the transparent slab so; a first shutter camera configured to capture a first video frame comprising a spot of light in the transparent slab when the at least one light source is turned on, wherein the spot of light is created by a user touching the transparent slab with a body part, wherein the touch of the user on the transparent slab disrupts the total internal reflection of a portion of the light thereby causing the portion of the light to be refracted into the body part of the user; a second shutter camera configured to capture a second video frame comprising ambient light near the transparent slab when the at least one light source is turned off; and a subtractor that subtracts the second video frame from the first video frame to create a third video frame that excludes ambient light, wherein the third video frame includes a signal representative of the touch of the user on the transparent slab. - View Dependent Claims (46, 47)
-
Specification