CN107845627B

CN107845627B - Multiple proximity detection light sensor

Info

Publication number: CN107845627B
Application number: CN201710907892.7A
Authority: CN
Inventors: 闫敏; 许星
Original assignee: Shenzhen Orbbec Co Ltd
Current assignee: Orbbec Inc
Priority date: 2017-09-29
Filing date: 2017-09-29
Publication date: 2020-02-18
Anticipated expiration: 2037-09-29
Also published as: CN107845627A

Abstract

The invention discloses an optical sensor, comprising: a substrate; a first light emitting unit disposed on the substrate for emitting a first light beam; a second light emitting unit disposed on the substrate for emitting a second light beam; a light detection unit disposed on the substrate for detecting the first light beam to determine a first approach distance of the object and also for detecting the second light beam to determine a second approach distance of the object; the first proximity distance is less than the second proximity distance. By arranging two light emitting units in the light sensor, the first light emitting unit emits a first light beam for detecting close proximity, and the second light emitting unit emits a second light beam for detecting far proximity, so that functional superposition is realized on the basis of not adding additional equipment, and multi-proximity detection is realized.

Description

Multiple proximity detection light sensor

Technical Field

The invention relates to the technical field of optics and electronics, in particular to a multi-proximity detection optical sensor.

Background

Optical sensors have been widely used in smart terminals, such as mobile phones, tablets, computers, and other devices. In mobile terminal equipment, the ambient light sensor is used for detecting the intensity of ambient light so as to further realize the automatic adjustment of screen brightness, the proximity sensor can detect whether an object is close to the equipment, particularly in equipment such as a mobile phone, the mobile phone needs to be close to the face when a user answers a call, and the proximity sensor can detect the phenomenon so as to control the screen and the like, thereby preventing the face from mistakenly touching the screen.

The 3D sensor can be applied to intelligent terminal equipment, particularly to a 3D sensor based on a structured light technology, three-dimensional measurement of a human face can be carried out by using the 3D sensor, a series of functions such as three-dimensional human face modeling and 3D human face recognition are further realized, and the 3D human face recognition can improve a biological recognition technology with higher accuracy than fingerprint recognition.

Along with the demand on the functions of the intelligent equipment is more and more, the demand on the functions of the optical sensor is higher and higher, and the traditional optical sensor with a single function is difficult to meet the demand. In the proximity sensor, it is often only possible to detect whether an object at a close distance is approaching, and the detection distance and range are single. For a 3D sensor, the sensor is usually composed of a projection module and an acquisition module, occupies more equipment space, but can only provide 3D imaging capability; in addition, the 3D sensor in the prior art cannot perform flood imaging on the target, so that high-precision identification is difficult to realize during face identification at night. The increase in demand leads to smart devices to add corresponding sensors mechanically, and the achieved effect is often a simple superposition of functions, and the effect of integrating to realize more functions is not achieved.

Disclosure of Invention

In order to solve the above problems, the present invention provides a high-density integrated optical sensor, which can realize the superposition of functions and realize the detection of multiple proximity without adding additional devices.

The present invention provides an optical sensor, comprising: a substrate; a first light emitting unit disposed on the substrate for emitting a first light beam; a second light emitting unit disposed on the substrate for emitting a second light beam; a light detection unit disposed on the substrate for detecting the first light beam to determine a first approach distance of the object and also for detecting the second light beam to determine a second approach distance of the object; the first proximity distance is less than the second proximity distance.

In some embodiments, the first light emitting unit has less power than the second light emitting unit.

In some embodiments, the emission angle of the first light emitting unit is smaller than the emission angle of the second light emitting unit.

In some embodiments, the light detection unit is further configured to detect the intensity of ambient light.

In some embodiments, the light detection unit is in an off state when detecting ambient light; and the light detection unit detects the first/second light beams and the ambient light when the first/second light emitting unit is turned on, and detects the first/second non-light beams by using a time-domain difference method.

In some embodiments, the first light beam is a different wavelength than the second light beam; and the light detection unit detects the first light beam and the second light beam simultaneously to judge the first approaching distance and the second approaching distance of the object.

In some embodiments, the light detection unit is configured with filters of different wavelengths to enable simultaneous detection of the first proximity distance and the second proximity distance; or the light detection unit is configured to perform proximity detection in two ways, one configured to perform detection of a first proximity distance according to intensity and the other configured to perform detection of a second proximity distance according to TOF.

In some embodiments, the first light emitting unit and the second light emitting unit are an integrated light emitting unit, and the integrated light emitting unit includes a light source array composed of a plurality of sub light sources and controllable in groups.

In some embodiments, the number of sub light sources corresponding to the first light emitting unit is smaller than the number of sub light sources corresponding to the second light emitting unit.

In some embodiments, the first light emitting unit and the second light emitting unit are VCSELs or VCSEL arrays.

The invention has the beneficial effects that: by arranging two light emitting units in the light sensor, the first light emitting unit emits a first light beam for detecting close proximity, and the second light emitting unit emits a second light beam for detecting far proximity, so that functional superposition is realized on the basis of not adding additional equipment, and multi-proximity detection is realized.

Drawings

Fig. 1 is a schematic structural diagram of a light sensor according to an embodiment of the present invention.

Fig. 2 is a device layout diagram of a photosensor in the related art.

Fig. 3 is a device layout diagram of a photosensor according to an embodiment of the present invention.

Fig. 4a is a schematic view of beam emission according to an embodiment of the present invention.

Fig. 4b is a schematic view of beam emission according to one embodiment of the present invention.

Fig. 5 is a device layout diagram of a photosensor according to an embodiment of the present invention.

Fig. 6 is a schematic view of a 3D imaging apparatus according to an embodiment of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the embodiments of the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element. The connection may be for fixation or for circuit connection.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the embodiments of the present invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be in any way limiting of the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.

FIG. 1 is a schematic diagram of a light sensor according to one embodiment of the present invention. The optical sensor 10 includes a substrate 101, a housing 102, a light emitting unit 104, a light detecting unit 105, and a grid 106, wherein the substrate 101 is a PCB circuit board, which provides support and electrical connection for the light emitting unit 104 and the light detecting unit 105, and the substrate 101 may be any other type, such as a flexible circuit board (FPC), a rigid-flex board, or a combination with other metals, ceramics, and the like. In one embodiment, the substrate 101 is a semiconductor material, and the light emitting unit 104 and the light detecting unit 105 can be directly formed on the semiconductor material. The light emitting unit 104 is used for emitting a light beam 109, which includes a light emitting device such as an LED, a laser diode, etc., and in one embodiment, the light beam 109 is an infrared invisible light beam. When the light beam 109 is irradiated to the target 20 and reflected to the light detection unit 105 as the light beam 110, the light detection unit 105 determines the proximity of the target object, i.e., the distance of the proximity, from the detected light beam. The light detection unit 105 includes a light receiving device such as a photodiode, a phototransistor, an image sensor, or the like.

The proximity determination generally includes two ways, one is that the light detection unit 105 estimates the distance of the target by detecting the intensity of the received light beam, and this way is generally used to determine whether there is an object approaching the device, without accurately measuring the distance of the object, such as a proximity sensor used in a device like a mobile phone, when a human face approaches during a call, the light intensity received by the light detection unit 105 increases, and when a certain threshold is exceeded, the human face is considered to be close enough to the mobile phone, and then the touch function of the screen and the information screen are turned off. Another way is to accurately measure the distance of the target according to the time of flight (TOF) by measuring the time from the light beam emitted from the light emitting unit 104 to the light beam received by the light detecting unit 105. The light detection unit 105 may be a single photodiode or a plurality of photodiodes, and in one embodiment, may be a multi-pixel image sensor. It is noted that in either case, the proximity detection is performed by an additional processor, for example, a processor in the mobile phone performs the proximity determination by data transmission and reception of the light emitting unit 104 and the light detecting unit 105, or the processor may be a dedicated processor of the sensor itself.

In order to prevent the light beam emitted from the light emitting unit 104 from directly entering the light detecting unit 105 without passing through the target 20, thereby causing an error, a grating 106 is provided therebetween. The housing 102 is provided with

windows

107, 108 corresponding to the light emitting unit and the light detecting unit, respectively, and the housing and the grating may be made of plastic, metal, or the like. When the sensor is integrated into a terminal device, such as a mobile phone, it is often placed under the screen 103, and the screen 103 is typically transparent to prevent excessive reflection of the

light beams

109 and 110.

Fig. 2 is a device layout diagram of a photosensor in the prior art. A light emitting unit 104 and a light detecting unit 105 are disposed on the substrate 101. In proximity detection, detection and judgment of only one distance can be realized, for example, a common proximity sensor only detects an object within 10cm, but in some applications, object detection at a longer distance or in a larger range is also required.

Fig. 3 is a device layout diagram of a photosensor according to one embodiment of the present invention. The difference from fig. 2 is that the light emitting unit 104 is composed of a first light emitting unit 1041 and a second light emitting unit 1042, wherein the first light emitting unit 1041 has a lower emitting power to realize a short-distance proximity detection, such as 0-10 cm, and the second light emitting unit 1042 has a higher emitting power to realize a long-distance proximity detection, such as 0-40 cm. The terminal equipment can open the corresponding light emitting unit according to different requirements of current application. In some embodiments, the light emitting unit includes a vertical cavity surface laser emitter (VCSEL) or an array thereof, which can make the sensor more miniaturized due to advantages of high stability and small size of the VCSEL.

In some embodiments, the light emitting unit is also provided with corresponding optics to modulate the emitted light beam, as shown in fig. 4a and 4 b. In the diagram shown in fig. 4a, for the light emitting unit 1041 for short-distance proximity detection as a single light emitting device, the emitted light beams are converged by the lens 401 and then emitted at θ₁The lens 401 can be placed at the window of the shell, the emitted light beams can be more concentrated through the convergence effect of the lens 401, and the light is prevented from being incident into the light detection unit without passing through a target. In the diagram shown in fig. 4b, the light emitting unit 1042 corresponding to the long-distance proximity detection is a light source array, and the emitted light passes through the beam expanderAfter the piece 402, at a greater launch angle theta₂And emits outward to realize the detection of the object in a wider range, and the beam expanding device can be a diffraction optical element, a diffuser and other optical devices.

The

light emitting units

1041 and 1042 may also be an integrated light emitting unit, such as an array light source composed of a plurality of VCSEL sub-light sources, in which the

light emitting units

1041 and 1042 independently emit light by grouping control. As shown in fig. 5, the light emitting unit 104 is an array light source, in which a few sub light sources, such as one sub light source 1041, are used for short-distance proximity detection, and the other sub light sources are used for long-distance proximity detection. The group control may be in any form, such as individually controlling several of the sub-light sources to be on for near proximity detection, turning on the other sub-light sources, i.e. for far proximity detection, or all light sources to be on simultaneously for far proximity detection.

The light detection unit 105 may be a single photodiode or a plurality of photodiodes. In one embodiment, the light detection unit 105 is a single photodiode that can perform switched detection of close proximity and far proximity. In another embodiment, the light detecting unit 105 is a multi-pixel image sensor (not shown), in which case the

light emitting units

1041 and 1042 can selectively emit light beams with different wavelengths, and in which case the light detecting unit 105 can implement simultaneous detection of light beams with two different wavelengths by configuring filters with different wavelengths. In some embodiments, proximity detection may also be performed in different manners using different subunits in the light detection unit 105, such as intensity detection of the light emission unit 1041 using a single detector in the light detection unit 105 to determine the proximity of the object, and TOF detection of the light emission unit 1042 using multiple detectors in the light detection unit 105 to calculate the proximity distance of the object. Likewise, whether a single photodiode or multiple photodiodes are employed by the light detection unit, detection of ambient light may be achieved by a time-domain filtering method, such as a time-domain difference method.

Due to the illumination of the ambient light, the light beam detected by the light detecting unit 105 actually includes the reflected light beam after the light beam emitted by the first light emitting unit 1041 and/or the second light emitting unit 1042 is reflected and the ambient light, and the ambient light can be ignored under the condition that the ambient light is not considered, and the light beam detected by the light detecting unit 105 is the reflected light beam after the light beam emitted by the first light emitting unit 1041 and/or the second light emitting unit 1042 is reflected by default.

The sensor 10 can also be used to detect the intensity of the ambient light under the condition that the ambient light needs to be considered, detect the intensity of the ambient light by the light detection unit 105 and realize the detection of the ambient light by the processor, and realize further processing according to the detection result, such as adjusting the screen brightness of the terminal device.

When the first light emitting unit 1041 and the second light emitting unit 1042 are turned off, the light detecting unit 105 can perform intensity detection of ambient light.

When proximity detection is performed, ambient light illumination often exists at the same time, the light detection unit 105 detects the intensity of the ambient light and the intensity of a reflected light beam after a light beam emitted by the first light emission unit 1041 and/or the second light emission unit 1042 is reflected, and the intensity of the reflected light beam can be obtained through a time-domain filtering method to implement proximity detection, for example, in an embodiment, a time-domain difference method is used, that is, the intensity of the ambient light is detected in an ambient light detection mode (when the first light emission unit 1041 and the second light emission unit 1042 are turned off), the total intensity of the ambient light and the reflected light beam is detected in a proximity detection mode at the next moment (when the first light emission unit 1041 and/or the second light emission unit 1042 are turned on), and intensity detection of the reflected light beam can be implemented through a. When the light emitting unit 104 includes a second light emitting unit having a larger power and a larger emission angle, the light source can be used to implement a floodlighting function. Fig. 6 is a schematic view of a 3D imaging apparatus according to an embodiment of the invention. The 3D imaging apparatus includes a support 601, and a first acquisition module 602, a light sensor 605, a projection module 607, and a circuit board 608 for controlling the respective modules installed therein. The 3D imaging apparatus can be embedded in a terminal device to implement functions such as 3D imaging, ambient light detection, proximity detection, etc., and in some embodiments, a second capturing module 603, such as an RGB camera, can be added to implement a photographing function, and a receiver 604 can be added to implement a calling function.

The optical sensor 605 includes a light emitting unit, a light detecting unit 6053, wherein the light emitting unit includes a first light emitting unit 6051 and a second light emitting unit 6052, and the second light emitting unit has a large power and can emit a light beam with a larger emission angle. At this time, the first light emitting unit emits a first light beam for proximity detection, and the second light emitting unit emits a second light beam for floodlight illumination of the 3D sensor.

For the 3D imaging function, the projection module 607 in the device is used to project a patterned light beam, such as an infrared speckle pattern light beam, the first collection module 602 is a corresponding infrared camera module, and is used to collect an object speckle image irradiated by the infrared speckle light beam, and finally, the processing circuit is used to calculate the 3D information of the object according to the speckle image to realize 3D imaging. However, in some applications, such as face recognition at night, it is often necessary to provide a flood image under flood lighting, which can be performed by using the second transmitting unit 6052 in the light sensor 605. The wavelength of the light beam emitted by the second light emitting unit 6052 should be the same as the wavelength of the light beam emitted by the projection unit 607, so that both the speckle image and the flood image can be collected by the same first collecting module 602. The wavelength of the light beam emitted by the second light emitting unit 6052 may also be different from the wavelength of the light beam emitted by the projection unit 607, and the two wavelength filters are used in the first acquisition module 602, so that part of pixels of the image sensor in the module image the light beam with the same wavelength as the light beam emitted by the second light emitting unit, and the other part of pixels image the light beam with the same wavelength as the light beam emitted by the projection unit 607.

In one embodiment, the first light emitting unit and the second light emitting unit are set to different wavelengths, the light detecting unit 6053 of the light sensor 605 is used to detect the first light beam with the wavelength corresponding to the first light emitting unit, and the first collecting module 602 is used to detect the second light beam with the wavelength corresponding to the second light emitting unit, which do not affect each other due to the difference in wavelength.

The foregoing is a more detailed description of the invention in connection with specific/preferred embodiments and is not intended to limit the practice of the invention to those descriptions. It will be apparent to those skilled in the art that various substitutions and modifications can be made to the described embodiments without departing from the spirit of the invention, and these substitutions and modifications should be considered to fall within the scope of the invention.

Claims

1. A light sensor, comprising:

a substrate;

a first light emitting unit disposed on the substrate for emitting a first light beam;

a second light emitting unit disposed on the substrate for emitting a second light beam;

a light detection unit disposed on the substrate for detecting the first light beam to determine a first approach distance of the object and also for detecting the second light beam to determine a second approach distance of the object;

the first proximity distance is less than the second proximity distance; the power of the first light emitting unit is smaller than that of the second light emitting unit, and the emission angle of the first light emitting unit is smaller than that of the second light emitting unit.

2. The light sensor of claim 1, wherein the light detection unit is further configured to detect an intensity of ambient light.

3. The light sensor according to claim 2, wherein the light detection unit is in an off state when detecting ambient light.

4. The optical sensor according to claim 3, wherein the light detecting unit detects the first/second light beam and the ambient light when the first/second light emitting unit is turned on, and detects the first/second light beam using a time-domain difference method.

5. The light sensor of claim 1, wherein the first light beam and the second light beam are of different wavelengths.

6. The optical sensor according to claim 5, wherein the light detection unit detects the first light beam and the second light beam simultaneously to determine the first proximity distance and the second proximity distance of an object.

7. The light sensor according to claim 1, wherein the first light emitting unit and the second light emitting unit are an integrated light emitting unit including a light source array composed of a plurality of sub light sources and controllable in groups.

8. The light sensor of claim 7, wherein the number of sub-light sources corresponding to the first light emitting unit is smaller than the number of sub-light sources corresponding to the second light emitting unit.