Method and apparatus for generating a control signal

• US 6,320,177 B1
• Filed: 03/07/2001
• Issued: 11/20/2001
• Est. Priority Date: 05/14/1996
• Status: Expired due to Fees

• Current Assignee: Michel Sayag
• Original Assignee: Michel Sayag
• Inventors: Sayag, Michel
• Primary Examiner(s): Lee, John R.
• Application Number:
  US09/801,425
• Time in Patent Office: 258 Days
• Field of Search: 250/208.1, 250/208.2, 250/208.3, 250/208.4, 250/208.5, 250/208.6, 250/221, 250/222.1, 250/216, 250/227.11, 250/227.13, 250/227.14, 250/227.2, 250/227.24, 250/227.26, 356/400, 345/156, 345/157, 345/158, 345/161, 345/163, 345/166, 345/173, 345/177, 345/179, 382/115, 382/116, 382/119, 382/124, 382/125, 382/126, 382/127
• US Class Current: 250/208.1
• CPC Class Codes: G06F 21/32 using biometric data, e.g. fingerprints, iris scans or voiceprints
• CPC Class Codes: G06F 21/83 input devices, e.g. keyboards, mice or controllers thereof
• CPC Class Codes: G06F 2203/0338 Fingerprint track pad, i.e. fingerprint sensor used as pointing device tracking the fingertip image
• CPC Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G06F 3/021 Arrangements integrating additional peripherals in a keyboard, e.g. card or barcode reader, optical scanner
• CPC Class Codes: G06F 3/0213 Arrangements providing an integrated pointing device in a keyboard, e.g. trackball, mini-joystick for pointing devices integrated in a laptop computer G06F1/169; joysticks G05G9/047; constructional details of pointing devices G06F3/033
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/03547 Touch pads, in which fingers can move on a surface
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06V 40/1324 by using geometrical optics, e.g. using prisms G06V40/1312 takes precedence
• CPC Class Codes: G07C 9/37 using biometric data, e.g. fingerprints, iris scans or voice recognition

Abstract

A method and apparatus for generating a control signal which corresponds to movement of an object in contact with a first surface are described. The apparatus includes a platen having the first surface. The platen is characterized by a critical angle beyond which light incident upon the first surface is not transmitted. A source of electromagnetic radiation emits electromagnetic radiation through the platen thereby illuminating the object. A detector having a plurality of sectors receives a portion of the electromagnetic radiation diffused by the object and transmitted through the platen beyond the critical angle. The sectors of the detector accumulate charge in response to the incident electromagnetic radiation. Conversion circuitry then converts the charge accumulated in the detector to the control signal, which in a specific embodiment is for controlling the movement of a pointer on a display.

Claims

1. An apparatus for capturing an image, complipsing a substantially spherical glass lens for transmitting electromagnetic radiation corresponding to the image, and a detector for receiving the electromagnetic radiation and generating charge corresponding to the image in response thereto, wherein the lens is coupled to the detector using a material having a first index of refraction which is substantially the same as a second index of refraction associated with the lens.

2. The apparatus of claim 1 wherein the lens is fixed relative to the detector.

3. The apparatus of claim 1 wherein the lens is movable relative to the detector.

4. The apparatus of claim 1 further comprising an aperture stop adjacent the lens to prevent any undesired light from impinging upon the detector.

5. The apparatus of claim 1 further comprising a second optical element having an aspherical surface associated therewith, the lens and the aspherical surface forming a telecentric lens system.

6. The apparatus of claim 5 wherein the second optical element further comprises a platen surface opposite the aspherical surface, the electromagnetic radiation being diffused by an object in contact with the platen surface beyond a critical angle associated with the second optical element.

7. The apparatus of claim 5 wherein a medium between the aspherical surface and the lens comprises air.

8. The apparatus of claim 1 wherein the lens is less than 5 mm in diameter.

9. The apparatus of claim 7 wherein the lens is approximately 2 mm in diameter.

10. The apparatus of claim 1 further comprising a mounting member on which the lens and detector are mounted.

11. The apparatus of claim 10 wherein the mounting member includes a concave surface to which the lens is coupled.

12. The apparatus of claim 10 wherein the diameter of the concave surface is greater than that of the lens, thereby allowing positioning of the lens relative to the detector.

13. The apparatus of claim 1 wherein the detector comprises a charge-coupled device.

14. An optical system for generating a magnified image of an object, comprising a substantially spherical glass lens for transmitting electromagnetic radiation corresponding to the image, and a detector for receiving the electromagnetic radiation and generating charge corresponding to the image in response thereto, wherein the lens is coupled to the detector using a material having a first index of refraction which is substantially the same as a second index of refraction associated with the lens.