Optical Touch Panel Having SMT Components As Optical Gates

• US 20090322708A1
• Filed: 06/30/2009
• Published: 12/31/2009
• Est. Priority Date: 06/30/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Xuan, Hawaii Wy, Parsons, Robert D., Lee, Edward Ys
• Granted Patent: US 8,643,608 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: H05K 3/30 Assembling printed circuits with electric components, e.g. with resistor
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.

Abstract

An optical touch panel and corresponding method are disclosed. The optical touch panel may comprise a rectangular position-detecting surface; a frame-shaped circuit board surrounding the rectangular position-detecting surface; a plurality of light-emitting elements configured for emitting a plurality of light beams, wherein the light-emitting elements are arranged along a first side of the rectangular position-detecting surface and disposed on the frame-shaped circuit board; a plurality of light-receiving elements configured for receiving light beams emitted by the plurality of light-emitting elements; a plurality of SMT components configured as optical gates for isolating ambient light to prevent erroneous light detection; and a control circuit. The plurality of SMT components and the plurality of light-receiving elements may be alternately arranged along a second side of the rectangular position-detecting surface opposite to the first side and disposed on the frame-shaped circuit board. The plurality of light-receiving elements may be arranged behind the plurality of SMT components.

Claims

1. An optical touch panel comprising:

a rectangular position-detecting surface;

a frame-shaped circuit board surrounding the rectangular position-detecting surface;

a plurality of light-emitting elements configured for emitting a plurality of light beams, wherein the plurality of light-emitting elements are arranged at various points along a first side of the rectangular position-detecting surface and disposed on the frame-shaped circuit board;

a plurality of light-receiving elements configured for receiving the plurality of light beams emitted by the plurality of light-emitting elements;

a plurality of SMT components configured as optical gates for isolating ambient light to prevent erroneous light detection; and

a control circuit configured for causing the plurality of light-emitting elements to emit the plurality of light beams in a predetermined order and further configured for causing the plurality of light-receiving elements to receive the plurality of light beams, thereby forming optical paths on the position-detecting surface in a grid pattern;

wherein the plurality of SMT components and the plurality of light-receiving elements are alternatively arranged at various points along a second side of the rectangular position-detecting surface opposite to the first side and disposed on the frame-shaped circuit board, and wherein the plurality of light-receiving elements are arranged at locations behind the plurality of SMT components.

2. The optical touch panel according to claim 1, wherein the plurality of SMT components comprise thin film resistors.

3. The optical touch panel according to claim 1, wherein the control circuit is further configured for causing the plurality of light-emitting elements to emit the plurality of light beams in a sequential order.

4. The optical touch panel according to claim 1, wherein the control circuit is further configured for causing a plurality of alternate light-emitting elements selected from the plurality of light-emitting elements to emit the plurality of light beams at a given time.

5. The optical touch panel according to claim 1, wherein the plurality of light-emitting elements comprise light emitting diodes.

6. The optical touch panel according to claim 1, wherein the plurality of light-receiving elements comprise photo transistors.

7. The optical touch panel according to claim 1, wherein if more than two of the plurality of light beams are blocked by an object, coordinates of an intended center position of the object are determined by averaging detected coordinate information.

8. A method of forming optical gates on a side of an optical touch panel, the method comprising disposing a plurality of SMT components and a plurality of light-receiving elements on a frame-shaped circuit board surrounding a rectangular position-detecting surface of the optical touch panel, the plurality of light-receiving elements being arranged at locations behind the plurality of SMT components such that the plurality of SMT components can be used as optical gates to prevent undesired interference caused by ambient light from reaching the plurality of light-receiving elements.

9. The method according to claim 8, wherein the plurality of SMT components comprise thin film resistors.

10. The method according to claim 8, wherein the plurality of light-receiving elements comprise photo transistors.