Sensing System

• US 20090090569A1
• Filed: 12/13/2008
• Published: 04/09/2009
• Est. Priority Date: 10/13/2005
• Status: Abandoned Application

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Lin, Cho-Yi
• Application Number:
  US12/334,449
• Publication Number:
  US 20090090569A1
• Time in Patent Office: Days
• US Class Current: 178/18.09
• CPC Class Codes: G01D 5/28 with deflection of beams of light, e.g. for direct optical indication G01D5/40 takes precedence; mechanical adjustment G01D5/264
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user
• CPC Class Codes: H04W 92/18 between terminal devices

Abstract

A sensing system includes a panel, a reflective element (RE), an image sensor (IS) and a processor electrically connected to the IS. The panel has a plane, a first area (FIA) having the first, second, third and fourth boundaries connected in order and a third area (TA) at the plane. The TA in the FIA is smaller than the FIA. The FIA and TA are quadrilaterals. The RE on the plane is disposed at the first boundary. A reflective mirror plane (RMP) of the RE perpendicular to the plane mirrors the FIA and TA to form a second area (SA) and a fourth area (FOA). The IS sensing the TA and FOA on the plane is disposed at the intersection of the third and fourth boundaries. An imaginary line passing through the IS, being perpendicular to the RMP and being located on the plane is outside the TA and FOA.

Claims

1. A sensing system adapted to sensing a pointer and calculating a location of the pointer, comprising:

a panel having a first plane, a first area located at the first plane and a third area located at the first plane, wherein the third area is located in the first area, the first area is quadrangular and has a first boundary, a second boundary, a third boundary and a fourth boundary which are connected in order, the third area is quadrangular, and the square measure of the third area is smaller than that of the first area;

a reflective element disposed at the first boundary and located on the first plane, wherein the reflective element has a second plane substantially perpendicular to the first plane, the second plane is a reflective mirror plane and mirrors the first area to form a second area, and the second plane mirrors the third area to form a fourth area;

an image sensor disposed at a corner at which the third boundary and the fourth boundary intersects and located on the first plane, wherein a sensing range of the image sensor covers the third area and the fourth area, and an imaginary line passing through the image sensor, being perpendicular to the second plane and being located at the first plane is located outside the third area and the fourth area; and

a processor electrically connected to the image sensor;

wherein when the pointer approaches the third area and the pointer is mirrored by the reflective element to form a first mirror image such that the pointer and the first mirror image is in the sensing range of the image sensor, the image sensor senses the pointer and the first mirror image and the processor calculates the location of the pointer.

2. The sensing system as claimed in claim 1, wherein the image sensor senses the pointer along a first sensing path and senses the first mirror image along a second sensing path, and the processor calculates the location of the pointer according to the first sensing path and the second sensing path.

3. The sensing system as claimed in claim 2, wherein the first area is a rectangle.

4. The sensing system as claimed in claim 3, wherein the third area is a rectangle, and one of four boundaries of the third area is parallel to or coincides with the third boundary of the first area.

5. The sensing system as claimed in claim 4, wherein a center of the third area coincides with that of the first area.

6. The sensing system as claimed in claim 4, wherein two of the boundaries of the third area coincide with the third boundary and the second boundary of the first area respectively.

7. The sensing system as claimed in claim 3, wherein the third area is quadrangular and not a rectangle.

8. The sensing system as claimed in claim 3, wherein the processor has information about a first distance “

D1”

from the first boundary to the third boundary, and the processor calculates the location of the pointer by the steps of;

determining a first angle “

A1”

between the first sensing path and the third boundary;

determining a second angle “

A2”

between the second sensing path and the third boundary; and

calculating a second distance “

D2”

from the pointer to the fourth boundary by means of dividing the double of D1 by the sum of tanA1 and tanA2.

9. The sensing system as claimed in claim 3, further comprising:

a first linear light source disposed at the second boundary and located on the first plane, wherein the first linear light source is mirrored by the reflective element to form a second mirror image; and

a second linear light source disposed at the third boundary and located on the first plane, wherein the second linear light source is mirrored by the reflective element to form a third mirror image, the fourth boundary is mirrored by the reflective element to form a fourth mirror image, the reflective element, the first linear light source, the second linear light source and the fourth boundary surround the first area, the reflective element, the second mirror image, the third mirror image and the fourth mirror image surround the second area, and at least part of the first linear light source, at least part of the second mirror image and at least part of the third mirror image are in the sensing range of the image sensor.

10. The sensing system as claimed in claim 3, further comprising:

a first light source disposed beside the image sensor;

a first reflector disposed at the second boundary and located on the first plane, wherein the first reflector is mirrored by the reflective element to form a second mirror image, the first reflector has a first retro-reflective surface, and the first retro-reflective surface is adapted to reflecting light emitted from the first light source; and

a second reflector disposed at the third boundary and located on the first plane, wherein the second reflector is mirrored by the reflective element to form a third mirror image, the second reflector has a second retro-reflective surface, the second retro-reflective surface is adapted to reflecting the light emitted from the first light source, the fourth boundary is mirrored by the reflective element to form a fourth mirror image, the reflective element, the first reflector, the second reflector and the fourth boundary surround the first area, the reflective element, the second mirror image, the third mirror image and the fourth mirror image surround the second area, and at least part of the first reflector, at least part of the second mirror image and at least part of the third mirror image are in the sensing range of the image sensor.

11. The sensing system as claimed in claim 10, wherein the first light source is adapted to emitting invisible light, the image sensor has an image-sensing window and a filter, the filter is disposed in front of the image-sensing window, and the filter filters out other light except the invisible light such that the invisible light passes through the filter.

12. The sensing system as claimed in claim 11, wherein the first light source is an infrared light emitting diode (IR LED) and the filter is IR-pass filter.

13. The sensing system as claimed in claim 2, further comprising a first light source located above the first plane and outside the third area, wherein the first light source is mirrored by the reflective element to form a second mirror image, the first light source and the second mirror image are located outside the sensing range of the image sensor, the pointer has a reflective surface, the first light source is adapted to emitting invisible light, and the first mirror image is formed by means of the first light source illumining the reflective surface of the pointer.

14. The sensing system as claimed in claim 2, wherein the pointer has a light emitting device, and the first mirror image is formed by means of light emitted from the light emitting device.