Sensitive display device comprising a scanned screen

• US 4,868,551 A
• Filed: 02/24/1987
• Issued: 09/19/1989
• Est. Priority Date: 10/28/1983
• Status: Expired due to Fees

• Current Assignee: Thomson-CSF
• Original Assignee: Thomson-CSF
• Inventors: Puech, Claude, Arditty, Herve
• Primary Examiner(s): Moore, David K.
• Assistant Examiner(s): FATAHI YAR, MAHMOUD
• Application Number:
  US07/018,731
• Time in Patent Office: 938 Days
• Field of Search: 340/706, 340/712, 340/365 P, 178/18, 250/221, 341/31
• US Class Current: 345/176
• CPC Class Codes: G06F 3/037 using the raster scan of a cathode-ray tube [CRT] for detecting the position of the member, e.g. light pens cooperating with CRT monitors
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

The sensitive display device of the invention comprises a scanned screen in front of which is situated a plate of transparent material; a detector being coupled with the edge of this plate and a specific position on this plate being determined by contact of a diffusing object, such as a finger. The detector picks up a signal which, after processing, enables the position of this point of contact to be determined. The invention may be used, in particular, as an interface between a computer and a user.

Claims

1. A sensitive display device comprising:

a scanned screen;

means for projecting a light spot onto said scanned screen;

means for detecting the designation of at least one particular position of said screen and for supplying a signal S(t) relating to said position;

means for processing said signal;

a plane light waveguide of transparent material situated in front of said scanned screen;

a diffusing object triggering said designation by contact with said waveguide, wherein said means for detection of said designation comprises at least one photodetector means coupled to at least one extremity of said waveguide wherein said plane waveguide internally transmits the light emerging from said light spot in the absence of said designation of a position and wherein said plane waveguide traps said light coming from said spot upon the occurrence of said designation of at least one position by coupling, within said waveguide, of the light transmitted through the waveguide up to said diffusing object wherein said trapped light is transmitted by successive reflections toward said photodetector means and wherein said plane waveguide is a plate which integrally includes at least one concentrating optical system including a shaped portion in the form of a corner having the same thickness as the rest of said plate which has one of said at least one photodetector coupled to each of said at least one concentrating system wherein each of said at least one concentrating system has an edge coupled to an edge of said plate in order to concentrate said trapped light.

2. A sensitive display device comprising:

a scanned screen;

means for projecting a light spot onto said scanned screen;

means for detecting the designation of at least one particular position of said screen and for supplying a signal S(t) relating to said position;

means for processing said signal;

a plane light waveguide of transparent material situated in front of said scanned screen;

a diffusing object triggering said designation by contact with said waveguide wherein said means for detection of said designation includes at least one photodetector means coupled to at least one extremity of said waveguide wherein said waveguide is a plate and wherein said photodetector means includes at least one photodetector coupled with the edge of said plate and wherein said plate waveguide internally transmits the light emerging from said light spot in the absence of said designation of a position and wherein said plane waveguide traps said light coming from said light spot upon occurrence of said designation of at least one position by coupling, within said waveguide, of the light transmitted through the waveguide up to the diffusing object wherein said transmitted light occurs by successive reflections toward said photodetector means and wherein at least one of said at least one photodetector is coupled with the edge of said plate by means of a plate edge extension wherein said plate edge extension is integral with the rest of said plate and has the same thickness as the rest of said plate and concentrates said transmitted light.

4. A device according to claim 2, wherein an optical focussing system is situated between the edge of said plate and the sensing surface of each photodetector.

5. A device according to claim 2 wherein a second waveguide is positioned between the edge of the plate and each photodetector.

6. A device according to claim 5, wherein said waveguide comprises a rod of transparent material.

7. A device according to claim 6, wherein said waveguide comprises at least one optical fibre.

8. A device according to claim 2, wherein the plate comprises a reflective coating deposited on its edge.

9. A device according to claim 2, wherein the plate has a common convex shape.

3. A sensitive display device comprising:

a scanned screen;

means for projecting a light spot onto said scanned screen;

means for detecting the designation of at least one particular position of said screen and for supplying a signal S(t) relating to said position;

means for processing said signal output from said means for detecting;

a plane light waveguide of transparent material in the form of a plate having one edge cut in bevelled form in order to concentrate light wherein said plate is situated in front of said scanned screen;

a diffusing object triggering said designation by contact with said waveguide wherein the means for detection of said designation comprises photodetector means coupled to at least one extremity of said waveguide and wherein said plate internally transmits the light emerging from said light spot in the absence of said designation of a position and wherein said plate traps said light coming from said light spot upon occurrence of said designation of at least one position by coupling, within said plate, the light transmitted through said plate up to the diffusing object and wherein said coupled light is transmitted by successive reflections toward said photodetector means.