Apparatus For Determining The Location Of A Pointer Within A Region Of Interest

• US 20070236454A1
• Filed: 06/13/2007
• Published: 10/11/2007
• Est. Priority Date: 10/09/2003
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: Smart Technologies Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Booth, David, Worthington, Stephen, Fletcher, Mark, UNG, CHI MAN, Sirotich, Roberto
• Granted Patent: US 8,456,418 B2
• Time in Patent Office: Days
• US Class Current: 345/158
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

An apparatus for detecting a pointer within a region of interest includes a first reflective element extending along a first side of the region of interest and reflecting light towards the region of interest. A second reflective element extends along a second side of the region of interest and reflects light towards the region of interest. The second side is joined to the first side to define a first corner. A non-reflective region generally in the plane of at least one of the first and second reflective elements is adjacent the first corner. At least one imaging device captures images of the region of interest including reflections from the first and second reflective elements.

Claims

1. An apparatus for detecting a pointer within a region of interest comprising:

a generally rectangular touch surface having an active sub-area defining said region of interest;

a detecting device looking across said sub-area from one corner of said touch surface; and

a first reflective element extending along one side of said touch surface and reflecting light towards said region of interest and towards said detecting device, wherein when a pointer is positioned within said region of interest, said detecting device sees said pointer and a reflection of said pointer appearing in said first reflective element, said active sub-area being sized to inhibit said detecting device from seeing a pointer within said region of interest that merges with said reflection to an extent that said pointer and reflection cannot be resolved.

2. An apparatus according to claim 1 wherein said detecting device includes an image sensor having an active pixel sub-array, light reflected by said first reflective element being directed towards said active pixel sub-array.

3. An apparatus according to claim 2 wherein said first reflective element is angled relative to said touch surface to aim reflected light towards said pixel sub-array.

4. An apparatus according to claim 1 further comprising at least one illumination source adjacent said detecting device, said illumination source directing light across said region of interest.

5. An apparatus according to claim 4 further comprising non-reflective material extending along the other sides of said touch surface and facing said detecting device.

6. An apparatus according to claim 5 wherein said active sub-area is delineated by an L-shaped margin about the periphery of said touch surface, said L-shaped margin having one arm extending generally the length of said first reflective element and a second arm extending towards said detecting device.

7. An apparatus for detecting a pointer within a region of interest comprising:

a first reflective element extending along a first side of said region of interest and reflecting light towards said region of interest;

non-reflective surfaces extending along the other sides of said region of interest; and

at least one imaging device capturing images of said region of interest including reflections from said first reflective element, said at least one imaging device having an active pixel sub-array and said first reflective element being configured to aim reflected light towards said active pixel sub-array.

8. An apparatus for detecting a pointer within a generally rectangular region of interest comprising:

a detecting device looking across said region of interest from one corner thereof;

a first reflective element extending along one side of said region of interest that is within the field of view of said detecting device and reflecting light towards said region of interest;

non-reflecting surfaces extending along the remaining sides of said region of interest; and

at least one illumination source for providing backlight illumination across said region of interest, wherein when a pointer is positioned within said region of interest, said detecting device sees said pointer directly and a reflection of said pointer in said first reflective surface.

9. An apparatus according to claim 8 wherein said detecting device calculates the location of said pointer within said region of interest via triangulation based on the pointer image and pointer reflection.

10. An apparatus according to claim 9 including a single illumination source disposed adjacent said one corner.