Touch panel apparatus

• US 5,414,413 A
• Filed: 06/06/1989
• Issued: 05/09/1995
• Est. Priority Date: 06/14/1988
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Togawa, Kazuo, Yoshida, Kimiyoshi, Tamaru, Hideshi, Sakano, Akio
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Saras, Steven J.
• Application Number:
  US07/362,020
• Time in Patent Office: 2,163 Days
• Field of Search: 340/712, 340/718, 340/709, 341/31, 250/221, 178/18, 345/173, 345/174, 345/175
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A touch panel apparatus of the type in which a plurality of photo-detecting pairs generate a plurality of detecting beams which cross the display surface and including a circuit for reducing the sensitivity of the photo-detecting pairs at the corners of the display surface to prevent malfunction due to reflected beams caused by the relatively higher intensity beams at those locations resulting from the relatively shorter beam lengths

Claims

1. A touch panel apparatus, comprising:

a display having a display surface with a substantially rectangular display area;

a plurality of photo-detecting means for generating a first set of a plurality of parallel detecting beams of different lengths passing across the display surface and a second set of a plurality of parallel detecting beams of different lengths passing across the display surface, wherein the detecting beams of the first set are skewed relative to the rectangular display area and to the detecting beams of the second set;

means for reducing the sensitivity of those of the photo-detecting means which have a relatively shorter beam length; and

a process circuit connected to the photo-detecting means for detecting the interrupted beams.

2. The touch panel apparatus of claim 1, wherein:

each of the photo-detecting means has a beam emitting device having a beam emitting power associated therewith; and

the means for reducing the sensitivity reduces the beam emitting power of the beam emitting devices having a relatively shorter beam length.

3. The touch panel apparatus of claim 1 wherein the display surface is substantially planar.

4. A touch panel apparatus, comprising:

a display having a display surface with a substantially rectangular display area;

a plurality of photo-detecting means for generating a first set of a plurality of parallel detecting beams of different lengths passing across the display surface and a second set of a plurality of parallel detecting beams of different lengths passing across the display surface, wherein the detecting beams of the first set are skewed relative to the rectangular display area and to the detecting beams of the second set, each of the photo-detecting means has a beam emitting device having a beam emitting power associated therewith and a separate beam receiving device in a photo coupled alignment with the beam emitting device;

means for reducing the sensitivity of those of the photo-detecting means which have a relatively shorter beam length by adjusting the photo coupling alignment between the beam emitting device and the beam receiving device; and

a process circuit connected to the photo-detecting means for detecting the interrupted beams.

5. A touch panel apparatus comprising:

a display having a curved display surface;

a first set of a plurality of photo-detecting means for generating a plurality of first parallel beams of differing lengths for passing across the display surface, the first set of photo-detecting means being provided at the periphery of the display surface;

a second set of a plurality of photo-detecting means for generating a plurality of second parallel beams of differing lengths for passing across the display surface, the second set of photo-detecting means being provided at the periphery of the display surface;

the first and second plurality of beams being skewed relative to the curve of the display surface;

means for reducing the sensitivity of the photo-detecting means which generate beams having a relatively shorter beamlength in comparison to the other beams generated by the first and second sets of photo-detecting means; and

a process circuit connected to the first and second sets of photo-detecting means for detecting interrupted beams and determining the location of the interrupted beams.

6. The touch panel apparatus of claim 5, wherein the first beams have positive angles relative to the direction of curvature of the display surface, and the second beams have negative angles relative to the direction of curvature of the display surface.

7. The touch panel apparatus of claim 5, wherein the means for reducing the sensitivity of the photo-detecting means which generate beams having a relatively shorter beam length further comprises means for filtering out steady state signals and high frequency, transient signals.

8. A touch panel apparatus, comprising:

a display having a display surface with a substantially rectangular display area;

a plurality of photo-detecting means for generating a plurality of detecting beams of different lengths passing across the display surface, wherein

the detecting beams are skewed relative to the rectangular display area,

each of the photo-detecting means has a beam emitting device having a beam emitting power associated therewith,

each of the photo-detecting means has a separate beam receiving device in a photo coupled alignment with it;

means for reducing the sensitivity of those of the photo-detecting means which have a relatively shorter beam length by adjusting the photo coupling alignment between the beam emitting device and the beam receiving device; and

a process circuit connected to the photo detecting means for detecting the interrupted beams.