OPTICAL SENSOR

• US 20150323670A1
• Filed: 11/22/2013
• Published: 11/12/2015
• Est. Priority Date: 01/31/2013
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: SHIRASAKA, Yasuyuki
• Granted Patent: US 9,772,404 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01J 1/0209 Monolithic
• CPC Class Codes: G01J 1/0214 Constructional arrangements for removing stray light
• CPC Class Codes: G01J 1/0411 using focussing or collimating elements, i.e. lenses or mirrors; Aberration correction
• CPC Class Codes: G01J 1/06 Restricting the angle of incident light
• CPC Class Codes: G01J 1/1626 Arrangements with two photodetectors, the signals of which are compared
• CPC Class Codes: G01P 13/00 Indicating or recording presence, absence, or direction, of movement electric switches H01H; counting moving objects G06M7/00
• CPC Class Codes: G01S 17/50 Systems of measurement based on relative movement of target
• CPC Class Codes: G01S 7/481 Constructional features, e.g. arrangements of optical elements
• CPC Class Codes: G01S 7/4813 Housing arrangements

Abstract

In order to provide an optical sensor that can accurately sense a direction of movement of an object to be sensed even in a case where disturbance light is present, an optical sensor of the present invention includes: a light-emitting element; a circularly-segmented light-receiving element group (RDPD), including light-receiving elements circularly provided at edges of a region on which reflected light from an object to be sensed reflecting light emitted by the light-emitting element is incident, for generating respective photocurrents upon receiving the reflected light; and a gesture circuit section for sensing a direction of movement of the object to be sensed upon receiving the photocurrents generated by the light-receiving elements included in the circularly-segmented light-receiving element group (RDPD).

Claims

1. An optical sensor comprising:

a light-emitting element;

a plurality of first light-receiving elements, circularly provided at edges of a region on which reflected light from an object to be sensed reflecting light emitted by the light-emitting element is incident, for generating respective photocurrents upon receiving the reflected light; and

a movement direction sensing section for sensing a direction of movement of the object to be sensed upon receiving the photocurrents generated by the plurality of first light-receiving elements.

2. The optical sensor as set forth in claim 1, further comprising:

a lens-shaped protrusion that has one of focal points which one is located in the region on which the reflected light is incident and that collects the reflected light in the region.

3. The optical sensor as set forth in claim 1, further comprising:

a second light-receiving element provided in a region inside a region in which the plurality of first light-receiving elements are circularly provided; and

an illuminance detecting section for detecting an illuminance upon receiving a photocurrent generated by the second light-receiving element.

4. The optical sensor as set forth in claim 1, further comprising:

a driving section for driving the light-emitting element in a first period, a second period, a third period, and a fourth period, which are consecutive, so that the light-emitting element is turned on or off during the first period and the fourth period and the light-emitting element is turned off or on during the second period and the third period;

an integrating section for integrating values of the photocurrents; and

an integrating control section for controlling the integrating section so that the integrating section performs integration in a positive direction or a negative direction during a period in which the light-emitting element is on and the integrating section performs integration in the negative direction or the positive direction during a period in which the light-emitting element is off.

5. The optical sensor as set forth in claim 1, further comprising:

a driving section for, in 2n consecutive periods where n is an integer that is not less than two, (i) driving the light-emitting element so that the light-emitting element is turned off or on during a first period and the light-emitting element is turned on or off during an n+1th period, and (ii) driving the light-emitting element so that turning on and turning off of the light-emitting element are alternately repeated for each of the periods in each of a first period group including the first period to an nth period and a second period group including the n+1th period to a 2nth period;

an integrating section for integrating values of the photocurrents; and

an integrating control section for controlling the integrating section so that the integrating section performs integration in a positive direction or a negative direction during a period in which the light-emitting element is on and the integrating section performs integration in the negative direction or the positive direction during a period in which the light-emitting element is off.

6. The optical sensor as set forth in claim 1, further comprising:

a photocurrent selecting section for selecting, from the photocurrents generated by the plurality of first light-receiving elements and in accordance with an intensity of disturbance light, a photocurrent to supply to the movement direction sensing section.