Optical sensor

Patent metadata

Field	Value
Publication number	US-9476901-B2
Application number	US-201414489543-A
Country	US
Kind code	B2
Filing date	Sep 18, 2014
Priority date	Mar 19, 2012
Publication date	Oct 25, 2016
Grant date	Oct 25, 2016

Abstract

Three light emitting elements and one light receiving element are provided on a surface of a substrate. An arithmetic processing portion of a signal processing circuit separates three reflected light signals from a light detection signal from the light receiving element. The arithmetic processing portion calculates a square sum of the difference between the entire waveforms of the reflected light signals while the reflected light signal is shifted. The arithmetic processing portion calculates a phase difference between the reflected light signals on the basis of a shift amount with which the calculated value is minimum. On the basis of similar processing, the arithmetic processing portion calculates a phase difference between the reflected light signals. The arithmetic processing portion identifies a movement direction of a detection object on the basis of the phase differences.

First claim

The invention claimed is:

1. An optical sensor comprising:
a substrate;
first, second and third light emitting elements disposed on the substrate;
a light emission controller configured to control the first, second and third light emitting elements;
at least one light receiving element disposed on the substrate and configured to receive reflected light that is emitted from the first, second and third light emitting elements and reflected from a detection object; and
a microprocessor configured to:
obtain first, second and third reflected light signals corresponding to the reflected light received by the at least one light receiving element from respective ones of the first, second and third light emitting elements;
calculate a first phase difference between the first and second reflected light signals by calculating a squared sum of the difference in the magnitude of the first and second reflected light signals along a predetermined portion of the waveforms of the first and second reflected light signals for each of a plurality of shifts in the phase of the first and second reflected light signals relative to one another and determining the first phase difference as a function of which of the squared sums is the smallest;
calculate a second phase difference between the second and third reflected light signals by calculating a squared sum of the difference in the magnitude of the second and third reflected light signals along a predetermined portion of the waveforms of the second and third reflected light signals for each of a plurality of shifts in the phase of the second and third reflected light signals relative to one another and determining the second phase difference as a function of which of the squared sums is the smallest; and
determine a movement direction of the detection object based on at least the first and second phase differences.

2. The optical sensor according to claim 1 , wherein the light emission controller controls each of the first, second and third light emitting elements to emit light by pulse emission in a time-division manner.

3. The optical sensor according to claim 1 , wherein each of the light emitting elements is a vertical cavity surface emitting laser.

4. An optical sensor comprising:
a substrate;
at least first, second and third light emitting elements disposed on the substrate;
a light emission controller configured to control the first, second and third light emitting elements;
at least one light receiving element disposed on the substrate and configured to receive reflected light that is emitted from the first, second and third light emitting elements and reflected from a detection object; and
a microprocessor configured to:
obtain first, second and third reflected light signals corresponding to the reflected light received by the at least one light receiving element from respective ones of the first, second and third light emitting elements;
calculate a first phase difference between the first and second reflected light signals by calculating a product sum of the difference in the magnitude of the first and second reflected light signals along a predetermined portion of the waveforms of the first and second reflected light signals for each of a plurality of shifts in the phase of the first and second reflected light signals relative to one another and determining the first phase difference as a function of which of the product sums is the largest;
calculate a second phase difference between the second and third reflected light signals by calculating a product sum of the difference in the magnitude of the second and third reflected light signals along a predetermined portion of the waveforms of the second and third reflected light signals for each of a plurality of shifts in the phase of the second and third reflected light signals relative to one another and determining the second phase difference as a function of which of the product sums is largest; and
determine a movement direction of the detection object based on at least the first and second phase differences.

5. An optical sensor comprising:
a substrate;
first, second and third light emitting elements disposed on the substrate;
a light emission controller configured to control the first, second and third light emitting elements;
at least one light receiving element disposed on the substrate and configured to receive reflected light that is emitted from the first, second and third light emitting elements and reflected from a detection object; and
a microprocessor configured to:
obtain first, second and third reflected light signals corresponding to the reflected light received by the at least one light receiving element from respective ones of the first, second and third light emitting elements;
calculate a first phase difference between the first and second reflected light signals and a second phase difference between the second and third reflected light signals; and
determine a movement direction of the detection object based on at least the first and second phase differences.

6. The optical sensor according to claim 5 , wherein the microprocessor is further to determine the movement direction of the detection object based on a ratio of the first phase difference to the second phase difference.

7. An optical sensor comprising:
a substrate;
first, second and third light emitting elements disposed on the substrate;
a light emission controller configured to control the first, second and third light emitting elements;
first, second and third light receiving elements disposed on the substrate adjacent to respective ones of the first, second and third light emitting elements, each of the light receiving elements configured to receive reflected light that is emitted from the adjacent light emitting element and reflected from a detection object; and
a microprocessor configured to:
obtain first, second and third reflected light signals corresponding to the reflected light received by respective ones of the first, second and third light receiving elements from the first, second and third light emitting elements;
calculate a first phase difference between the first and second reflected light signals by calculating a squared sum of the difference in the magnitude of the first and second reflected light signals along a predetermined portion of the waveforms of the first and second reflected light signals for each of a plurality of shifts in the phase of the first and second reflected light signals relative to one another and determining the first phase difference as a function of which of the squared sums is the smallest;
calculate a second phase difference between the second and third reflected light signals by calculating a squared sum of the difference in the magnitude of the second and third reflected light signals along a predetermined portion of the waveforms of the second and third reflected light signals for each of a plurality of shifts in the phase of the second and third reflected light signals relative to one another and determining the second phase difference as a function of which of the squared sums is the smallest; and
determine a movement direction of the detection object based on at least the first and second phase differences.

8. An optical sensor comprising:
a substrate;
first, second and third light emitting elements disposed on the substrate;
a light emission controller configured to control the first, second and third light emitting elements;
first, second and third light receiving elements disposed on the substrate adjacent to respective ones of the first, second and third light emitting elements, each of the light receiving elements configured to receive reflected light that is emitted from the adjacent l

Assignees

• Murata Manufacturing Co

Inventors

• Ishikawa Hiroto

Classifications

• H03K2217/94111

  having more than one emitter · CPC title

• G06F3/017

  Gesture based interaction, e.g. based on a set of recognized hand gestures (interaction based on gestures traced on a digitiser G06F3/04883) · CPC title

• G01P13/04 Primary

  Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement · CPC title

• G06F3/0304

  Detection arrangements using opto-electronic means (constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042) · CPC title

• G01P13/02 Primary

  Indicating direction only, e.g. by weather vane · CPC title