Method and apparatus for low power optical sensing and decoding of data

• US 5,281,800 A
• Filed: 12/23/1991
• Issued: 01/25/1994
• Est. Priority Date: 12/23/1991
• Status: Expired due to Term

• Current Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Original Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Inventors: Pelton, Walter E., Emery, David L.
• Primary Examiner(s): SHEPPERD, JOHN W
• Application Number:
  US07/812,769
• Time in Patent Office: 764 Days
• Field of Search: 235/462, 235/467, 235/472
• US Class Current: 235/462.06
• CPC Class Codes: G06K 2007/10495 Circuits for pulse forming, amplifying
• CPC Class Codes: G06K 7/10841 Particularities of the light-sensitive elements semiconductor devices H01L

Abstract

A portable optical data reader for optically sensing and decoding data, comprising a carrier oscillator for producing a carrier signal at a predetermined frequency, an optical emitter electrically connected to the carrier oscillator for emitting optical radiation in an optical path to an optical data carrier at the predetermined frequency, an optical detector for detecting the emitted optical radiation returning from the optical data carrier thereby receiving the optical data and producing a detected electrical signal responsive thereto, and a double balanced demodulator electrically connected to the optical detector and the carrier oscillator for combining the detected radiation signal with the carrier signal to demodulate the optical data with the optical data carrier.

A method of sensing and decoding optical data comprising-the steps of oscillating a carrier signal, transmitting the carrier signal to an optical emitter, thereby illuminating the optical emitter adjacent optical data, reflectively sensing the illumination from the optical emitter, thereby receiving the optical data, and demodulating the optical data by use of the oscillating carrier signal.

Claims

1. An optical data reader, comprising:

optical emitting means for emitting optical radiation in an optical path to an optical data carrier;

optical detecting means for detecting optical radiation emerging from the optical data carrier and for producing an electrical signal responsive thereto; and

incremental amplifying means electrically connected to said optical detecting means for providing non-zero amplification of low frequencies and greater amplification of higher frequencies of the electrical signal responsive to the optical radiation detected by said optical detecting means.

2. The optical data reader according to claim 1, further comprising:

timing signal generating means electrically connected to said optical emitting means for producing a timing signal at a predetermined frequency so that said optical emitting means emits optical radiation at the predetermined frequency responsive to said timing signal generating means; and

double balanced demodulation means electrically connected to said incremental amplifying means and said timing signal generator for demodulating the electrical signal produced by said optical detecting means at the predetermined frequency produced by said timing signal generating means.

3. The optical data reader according to claim 2, wherein said timing signal generating means comprises oscillating means for producing a carrier signal at the predetermined frequency.

4. The optical data reader according to claim 2, wherein said timing signal generating means frequency is preselectable.

5. The optical data reader according to claim 1, further comprising:

timing signal generating means electrically connected to said optical emitting means for producing a first timing signal at a first frequency and a second timing signal at a second frequency, and for controllably providing one of the first or second timing signals to said optical emitting means, so that said optical emitting means emits optical radiation at one of the first or second frequencies responsive to said timing signal generating means.

6. The optical data reader according to claim 5, further comprising:

double balanced demodulation means electrically connected to said incremental amplifying means and said timing signal generating means for demodulating the electrical signal produced by said optical detector at one of the first or second frequencies produced by said timing signal generating means.

7. The optical data reader according to claim 5, further comprising:

activity detection means electrically connected to said optical detector means and said timing signal generating means for detecting change in the electrical signal, and for controlling said timing signal generating means to generate the first or second frequency responsive to said activity detection means detecting the change in the electrical signal.

8. An optical data reader, comprising:

timing signal generating means for producing first timing signals at a first frequency and second timing signals at a second frequency, the second timing signals being generated by selecting predetermined first timing signals;

optical emitting means electrically connected to said timing signal generating means for emitting optical radiation responsive to said timing signal generating means and in an optical path to the optical data carrier at one of the first or second frequencies; and

optical detecting means for detecting optical radiation emerging from the optical data carrier and for producing an electrical signal responsive thereto.

9. An optical data reader according to claim 8, further comprising:

double balanced demodulation means electrically connected to said optical emitting means and said timing signal generating means for demodulating the electrical signal produced by said optical detecting means at one of the first or second frequencies produced by said timing signal generating means.

10. The optical data reader according to claim 9, wherein said timing signal generating means frequency is preselectable.

11. The optical data reader according to claim 8 wherein said timing signal generating means comprises oscillating means for producing a carrier signal at one of said first or second frequencies.

12. The optical data reader according to claim 8, further comprising:

activity detection means electrically connected to said optical detector means and said timing signal generating means for detecting change in the electrical signal produced by said optical detector means, and for controlling said timing signal generating means to generate the first or second frequency responsive to said activity detection means detecting the change in the electrical signal.

13. A method of reading optical data, comprising the steps of:

generating a timing signal having a predetermined frequency;

emitting optical radiation responsive to the generating timing signal in an optical data path to an optical data carrier;

detecting optical radiation emerging from the optical data carrier;

producing an electrical signal responsive to the detected optical data; and

providing non-zero amplification of low frequencies and greater amplification of higher frequencies of the electrical signal.

14. The method of reading optical data according to claim 13, further comprising the step of:

double balanced demodulating the electrical signal responsive to detected surface reflectivity of optical radiation emerging from the optical data carrier and the predetermined frequency of the generated timing signal.

17. The method of reading optical data according to claim 14, further comprising the steps of:

detecting change in the electrical signal; and

controlling the timing signal to generate one of the first or second timing signals in response to detecting the change in the electrical signal.

15. A method of reading optical data, comprising the steps of:

generating first timing signals having a first frequency;

generating second timing signals having a second frequency by selecting predetermined first timing signals;

emitting optical radiation responsive to the first or second generated timing signals in an optical data path to an optical data carrier;

detecting optical radiation emerging from an optical data carrier; and

producing an electrical signal responsive to detected optical radiation emerging from the optical data carrier.

16. A method of reading optical data according to claim 15, further comprising the step of:

double balanced demodulating the produced electrical signal responsive to one of the first or second frequencies of the generated timing signals.