JP2013190401A - Optical sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical sensor which has a simple structure easily installable to equipment, and is capable of determining positional relationship between an object and a sensor.SOLUTION: An optical sensor (100) has a light detection section (10) and a determining section (11). The light detection section is equipped with: a member having a hollow for blocking ambient light other than detection light, and a through hole (3a) for leading the detection light into the hollow; and a first light detection section (1) and a second light detection section (2) which is arranged at a predetermined position on the bottom of the hollow. The first light detection section is arranged at a position where the axis of the through hole passes through, and the second light detection section is arranged on a peripheral part and the same plane as the first light detection section. The determining section, in the case where each of the first light detection section and the second light detection section output a signal indicating that they detected an object (7), determines that the object is at a closer position from the optical sensor than a predetermined distance, and in the case where only the first light detection section outputs a signal indicating that it detected the object, determines that the object is at a farther position from the optical sensor than the predetermined distance.

Description

  The present invention relates to an optical sensor, and more particularly to an optical sensor that determines a relative positional relationship between an object and the optical sensor.

  Passive infrared sensors are generally used as devices that determine the approach of the human body by detecting thermal radiation (heat radiation) from the human body, and these infrared sensors have been incorporated for the purpose of reducing power consumption. Electronic devices are being developed. As an example, for example, a television set configured to turn off the power of the apparatus when the infrared sensor disposed at a predetermined position no longer detects infrared rays emitted from the human body. When an infrared sensor is used for such an application, the role of the infrared sensor is to detect whether or not an object to be detected (for example, a human body) exists within the detection range of the sensor.

  On the other hand, a device such as a smartphone or a tablet personal computer (hereinafter referred to as a portable terminal) has a function of operating a cursor on the screen by reading a finger movement using an infrared sensor. It becomes possible. In such a case, when a conventional infrared sensor is used, infrared light radiated from the human head or torso is also detected, which causes a problem of malfunction. In order to solve such a malfunction problem, it is only necessary to set the operation to be effective only when the human body approaches the infrared sensor closer than a predetermined distance. For this reason, the apparatus shown in patent document 1 is proposed as a sensor apparatus which can detect that the detection target has come closer than a predetermined distance.

Japanese Patent Application Laid-Open No. 2004-267997

  However, the conventional method as disclosed in Patent Document 1 requires a plurality of members each having an infrared sensor and a through hole that restricts the field of view of the infrared sensor, resulting in a complicated structure. There is. Furthermore, in such a conventional method, since it is necessary to arrange these sensors three-dimensionally, when these sensors are mounted on a device, particularly when mounted on a relatively thin device such as a portable terminal. In addition, the structure is inconvenient.

  An object of the present invention is to provide an optical sensor capable of determining the positional relationship between an object and a sensor having a simple structure that can be easily mounted on a device.

  In order to solve the above-described problems, an optical sensor of the present invention includes a first light detection unit and a second light detection unit that detect radiated light from a predetermined object, the first light detection unit, and the above A member having a through hole for giving a different field of view to the second light detection unit, and a relative relationship between the object and the light sensor based on output signals from the first light detection unit and the second light detection unit; An optical sensor including a determination unit configured to determine a general positional relationship, wherein the first light detection unit is disposed at a position where the axis of the through hole passes, and the second light detection unit is The peripheral portion of the first light detection unit is disposed on the same plane, and the determination unit receives a signal indicating that each of the first light detection unit and the second light detection unit has detected an object. When output, it is determined that the object is closer than the predetermined distance from the optical sensor, and If only the first light detection section outputs a signal indicating the detection of the object, the object is characterized in determining that there from the optical sensor in a position farther than a predetermined distance.

  Here, when the determination unit outputs a signal indicating that only the second light detection unit has detected the object, the object is located at a position away from the axis of the through hole by a predetermined angle or more. It can be characterized by determining.

  The member includes a cavity for blocking ambient light other than the emitted light from the object, and the through-hole for guiding the emitted light from the object into the cavity. The light detection unit and the second light detection unit are disposed at the bottom of the cavity facing the through hole, and the center of the first light detection unit is located on an extension line of the central axis of the through hole. The second light detection unit may be arranged at a position that uniformly surrounds the periphery of the first light detection unit.

  Further, the determination unit determines whether or not the amplified signal from the first photodetection unit 1 and an amplifier for amplifying the signal from the first photodetection unit are equal to or greater than a predetermined threshold value. A first determination circuit for determining, an amplifier for amplifying the signal from the second light detection unit 2, and whether the amplified signal from the second light detection unit is equal to or greater than a predetermined threshold value A second determination circuit that determines whether or not, a digital arithmetic circuit that determines a relative position of the object based on a determination result from the first determination circuit and a determination result from the second determination circuit; It can be characterized by comprising.

In addition, the first and second light detection units may include InAs _x Sb _1-x (0 ≦ _x ≦ 1) on a light receiving surface that detects radiated light from the object.

  Further, the object may be a human body.

  According to the present invention, an optical sensor capable of determining the relative positional relationship between an object and a sensor having a structure that is simpler and easier to mount on a device than the related art can be obtained by the above configuration.

  Furthermore, according to the present invention, for example, when applied to a non-contact input of a portable terminal, the operation is set to be effective only when the human body approaches the optical sensor closer than a predetermined distance. Can be prevented, and the operational reliability can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure showing the positional relationship of the member which has the 1st photon detection part and 2nd photon detection part which comprise the photosensor of one Embodiment of this invention, and a through-hole, Comprising: FIG. 1 (A) is a front view. FIG. 1B is a cross-sectional view. It is a block diagram which shows schematic structure of the optical sensor of one Embodiment of this invention. It is explanatory drawing shown about the relative positional relationship of the optical sensor and object of one Embodiment of this invention, and the correlation of the detected signal.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

(Light detector)
In the embodiment of the present invention (hereinafter referred to as the present embodiment), as shown in FIGS. 1 and 2, the light detection unit 10 includes a cavity for blocking ambient light other than detection light, and detection light. A member 3 having a through hole 3a for guiding into the cavity is provided, and a first light detection unit 1 and a second light detection unit 2 arranged at predetermined positions on the bottom of the cavity. The sensor elements of the first light detection unit 1 and the second light detection unit 2 constituting the light detection unit 10 are not particularly limited as long as they can output a signal corresponding to incident light. . For example, when using an infrared sensor for the purpose of detecting the human body, the temperature due to infrared absorption, such as a “quantum sensor” that outputs a signal by photoelectric conversion, such as a photodiode or photoconductor, a thermopile or a pyroelectric sensor, etc. A “thermal sensor” that converts the change into an electrical signal can be used. For the purpose of detecting a human body, it is more preferable to use a quantum sensor from the viewpoint of easily performing static state detection. In the case of a quantum sensor, it is preferable that InAs _x Sb _1-x (0 ≦ _x ≦ 1) is included in the light receiving surface from the viewpoint of efficiently detecting infrared rays emitted from the human body.

(First light detection unit)
The first light detection unit 1 is not particularly limited as long as at least a part of the first light detection unit 1 passes at a position where the central axis of the through hole 3a of the member 3 passes. From the viewpoint of suppressing detection variation due to the orientation (the orientation of the sensor with respect to the object to be detected), as shown in FIG. 1B, the center of the first light detection unit 1 is on the extension line of the central axis of the through hole 3a. The structure located at is preferred.

  In order to prevent the field of view from being biased depending on the orientation, the shape of the first light detection unit 1 is preferably a circle or a regular polygon.

(Second light detection unit)
The second light detection unit 2 is not particularly limited as long as it is a peripheral part of the first light detection unit 1 and arranged on the same plane, but from the viewpoint of suppressing detection variation due to orientation, FIG. As shown to (A), it is preferable to arrange | position so that the outer periphery of the 1st photon detection part 1 may be surrounded.

  As with the first light detection unit 1, it is desirable that the second light detection unit 2 is not biased in the visual field depending on the orientation, and as shown in FIG. An arrangement that uniformly surrounds the periphery is preferred.

(Object to be detected)
In the present embodiment, the object 7 to be detected (see FIG. 3) is not particularly limited as long as it is a substance that emits infrared rays, and examples thereof include living bodies such as human bodies and fingertips, and artificial objects such as machines.

(Radiated light from objects)
In the present embodiment, the emitted light from the object 7 means an electromagnetic wave radiated from the object, such as visible light or infrared light. When a person is a detection target, the emitted light becomes infrared rays having a wavelength of 2 to 30 μm (peak is around 10 μm).

(Member with a through hole)
In the present embodiment, the member 3 having the through hole 3a is a member intended to give different views to the first light detection unit 1 and the second light detection unit 2, respectively. The material of the member 3 having the through hole 3a is preferably made of a material having as low a transmittance as possible to detect light. For example, when the detected light is infrared, metal, resin, and ceramic are preferable. Further, in order to prevent problems due to reflection and scattering of radiated light, the inner wall of the through hole is preferably made of a material having low reflectance.

(Judgment part)
As illustrated in FIGS. 2 and 3, the determination unit 11 according to the present embodiment outputs a signal indicating that the first light detection unit 1 and the second light detection unit 2 have detected the object 7. If it is determined that the object 7 is at a position closer than the predetermined distance from the optical sensor 100 and only the first light detection unit outputs a signal indicating that the object 7 has been detected, the object 7 Has a function of determining that the sensor is at a position farther from the optical sensor 100 than a predetermined distance. Further, when the determination unit 11 outputs a signal indicating that only the second light detection unit 2 has detected the object 7, the position of the object 7 is more than a predetermined angle away from the axis of the through hole 3a. It is preferable to have a function of determining that the user is in

  As shown in FIG. 2, the specific configuration of the determination unit 11 includes an amplifier 4a for amplifying a signal from the first light detection unit 1, and a first light detection unit amplified by the amplifier 4a. A first determination circuit 5a for determining whether or not the signal from 1 is equal to or greater than a threshold value, an amplifier 4b for amplifying the signal from the second photodetecting section 2, and a first amplifier amplified by the amplifier 4b A second determination circuit 5b for determining whether or not the signal from the second light detection unit 2 is equal to or greater than a threshold; a determination result S1 from the first determination circuit 5a; and a determination result from the second determination circuit 5b An example of the determination unit 11 includes the digital arithmetic circuit 6 that determines the relative position of the object 7 based on S2. The first and second determination circuits 5a and 5b and the digital arithmetic circuit 6 can be replaced with a general arithmetic processing unit (CPU) and software.

(Description of operation)
Next, the operation of the optical sensor 100 of this embodiment will be described with reference to FIG. FIG. 3 shows the relative positional relationship between the optical sensor 100 shown in FIG. 2 and the predetermined object 7 as the light source, and the correlation between the detected signals S1, S2, and S3.

  With respect to the detection signal S1 from the first determination circuit 5a and the detection signal S2 from the second determination circuit 5b, the mark indicates that the signals from the first and / or second light detection units 1 and 2 are predetermined. This indicates that signals S1 and S2 that are equal to or greater than the threshold and indicate that the object 7 is present in the field of view of the first and / or second light detection units 1 and 2 are output. The signals from the first and / or second light detection units 1 and 2 are less than a predetermined threshold value, and the signals S1 and S2 are not output, and the first and / or second light detection units 1 and 2 are output. Indicates that there is no object in the field of view.

  In the positional relationship as shown in FIG. 3A, each of the first light detection unit 1 and the second light detection unit 2 outputs a signal indicating that the object 7 has been detected. Since the threshold value is exceeded, each of the detection signal S1 from the first determination circuit 5a and the detection signal S2 from the second determination circuit 5b is ON (marked), and based on these detection signals S1 and S2. The digital arithmetic circuit 6 determines that the object 7 is located near the predetermined distance from the optical sensor 100 in the vicinity of the axis of the through hole 3a. The determination result of the digital arithmetic circuit 6 is output from the digital arithmetic circuit 6 to a device (not shown) such as a portable terminal as a position determination output signal S3 having a value indicating the position mode 1, for example.

  In the positional relationship as shown in FIG. 3B, only the first light detection unit 1 outputs a signal indicating that the object 7 has been detected, and only the signal exceeds a predetermined threshold. Since only the detection signal S1 from the first determination circuit 5a is ON (marked) and the detection signal S2 from the second determination circuit 5b is OFF (×), the object is detected based on these detection signals S1 and S2. 7 is determined by the digital arithmetic circuit 6 to be at a position farther from the optical sensor 100 than the predetermined distance in the vicinity of the axis of the through hole 3a. The determination result of the digital arithmetic circuit 6 is output from the digital arithmetic circuit 6 to a device such as a portable terminal as a position determination output signal S3 having a value indicating the position mode 2, for example.

  In the positional relationship as shown in FIG. 3C, only the second light detection unit 2 outputs a signal indicating that the object 7 has been detected, and only the signal exceeds a predetermined threshold value. Only the detection signal S2 from the second determination circuit 5b is ON (marked), and the detection signal S1 from the first determination circuit 5a is OFF (marked by x). Based on these detection signals S1 and S2, the object 7 is determined by the digital arithmetic circuit 6 to be at a position more than a predetermined angle with respect to the axis of the through hole 3a. The determination result of the digital arithmetic circuit 6 is output from the digital arithmetic circuit 6 to a device such as a portable terminal as a position determination output signal S3 having a value indicating the position mode 3, for example.

  Although not shown in FIG. 3, when neither the first light detection unit 1 nor the second light detection unit 2 outputs a signal indicating that the object 7 has been detected, the detection signals S1 and S2 are Since both are OFF (x mark), the object 7 is not located in any field of view of the first light detection unit 1 and the second light detection unit 2 based on the detection signals S1 and S2. Is determined by the digital arithmetic circuit 6. The determination result of the digital arithmetic circuit 6 is output from the digital arithmetic circuit 6 to a device such as a portable terminal as a position determination output signal S3 having a value indicating the position mode 4, for example.

(Other embodiment examples)
In the above, the preferred embodiments of the present invention have been illustrated and described. However, the embodiments of the present invention are not limited to the above illustrations, and the constituent members thereof are within the scope of the claims. Various modifications such as replacement, change, addition, increase / decrease in number, change in shape design, etc. are all included in the embodiments of the present invention. In addition, the present invention may be applied to a system composed of a plurality of devices, or may be applied to an apparatus composed of one device. For example, in FIGS. 1 and 2, the housing of the light detection unit 10 of the optical sensor 100 is shown as a rectangular box shape, but may be, for example, a circular liquor shape or a conical shape. In such a case, the 1st photon detection part 1 and the 2nd photon detection part 2 can be arrange | positioned concentrically.

  The determination unit 11 may be configured as a part of an integrated circuit integrated with the light detection unit 10 or may be disposed at a position separated from the light detection unit 10 via wired or wireless.

  1 and 3 is filled with an optically transparent material such as crystal glass or transparent acrylic, and the light incident position of the through-hole 3a is filled. An antireflection film may be provided on the surface. When such a structure is employed, it is possible to manufacture using a general manufacturing technique of an integrated circuit. For example, the first and second light detection units are located at the bottom of a block body such as acrylic. After pasting 1 and 2, there is an advantage that it can be formed by adopting a relatively simple manufacturing method such as omitting the portion of the through hole 3a and covering or coating the entire block with a light blocking material. .

  Further, for the purpose of reducing the thickness of the optical sensor 100, particularly the light detection unit 10, a wide-angle lens body may be fitted in the through hole 3a or in the vicinity thereof.

  Further, in FIG. 1 and the like, the first photodetection unit 1 and the second photodetection unit 2 are exemplified, but the second photodetection unit 2 is further divided into a plurality of photodetection units (sub- It can be expected that the inclination angle of the object 7 with respect to the optical sensor 100 (see FIG. 3C) can be detected with higher accuracy by dividing the optical detection unit).

  Although the optical sensor 100 of the present invention can of course achieve the detection purpose alone, a plurality of optical sensors 100, for example, three optical sensors 100, and the through holes of the three optical sensors 100 are provided. It can be expected that the position and motion of the object 7 can be detected more accurately by arranging the axes so as to intersect at the target (target) detection position of the object 7.

DESCRIPTION OF SYMBOLS 1 1st light detection part 2 2nd light detection part 3 Member 4a, 4b which has a through-hole Amplifier 5A 1st determination circuit 5B 2nd determination circuit 6 Digital arithmetic circuit 7 Object (light source)
DESCRIPTION OF SYMBOLS 10 Light detection part 11 Determination part 100 Optical sensor S1 Output signal S2 of 1st determination circuit Output signal S2 of 2nd determination circuit Position determination output signal

Claims (6)

A first light detection unit and a second light detection unit for detecting emitted light from a predetermined object;
A member having a through hole for giving different visual fields to the first light detection unit and the second light detection unit;
An optical sensor comprising: a determination unit configured to determine a relative positional relationship between the object and the photosensor based on output signals from the first light detection unit and the second light detection unit;
The first light detection unit is disposed at a position where the axis of the through hole passes,
The second photodetecting unit is disposed on the same plane as the periphery of the first photodetecting unit,
When the determination unit outputs a signal indicating that each of the first light detection unit and the second light detection unit has detected an object, the object is closer than a predetermined distance from the light sensor. When it is determined that the object is located, and only the first light detection unit outputs a signal indicating that the object is detected, it is determined that the object is located at a position farther than a predetermined distance from the optical sensor. Features an optical sensor.   When the determination unit outputs a signal indicating that only the second light detection unit has detected the object, the determination unit determines that the object is at a position separated from the axis of the through hole by a predetermined angle or more. The optical sensor according to claim 1.   The member includes a cavity for blocking ambient light other than light emitted from the object, and the through-hole for guiding light emitted from the object into the cavity. And the second photodetecting portion is disposed at the bottom of the cavity facing the through hole, and the center of the first photodetecting portion is located on an extension line of the central axis of the through hole, 3. The optical sensor according to claim 1, wherein the two light detection units are arranged at positions that uniformly surround the periphery of the first light detection unit. The determination unit
An amplifier for amplifying a signal from the first light detection unit;
A first determination circuit that determines whether the amplified signal from the first light detection unit 1 is equal to or greater than a predetermined threshold;
An amplifier for amplifying the signal from the second photodetecting section 2;
A second determination circuit that determines whether or not the amplified signal from the second light detection unit is equal to or greater than a predetermined threshold;
And a digital arithmetic circuit that determines a relative position of the object based on a determination result from the first determination circuit and a determination result from the second determination circuit. The optical sensor according to any one of claims 1 to 3. The first and second light detection units include InAs _x Sb _1-x (0 ≦ _x ≦ 1) on a light receiving surface that detects radiation emitted from the object. 5. The optical sensor according to any one of 4 above.   The optical sensor according to claim 1, wherein the object is a human body.

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