CN109445239B

CN109445239B - Optical projection module, sensing device and equipment

Info

Publication number: CN109445239B
Application number: CN201811375426.XA
Authority: CN
Inventors: 林峰
Original assignee: Shenzhen Fushi Technology Co Ltd
Current assignee: Shenzhen Fushi Technology Co Ltd
Priority date: 2018-11-19
Filing date: 2018-11-19
Publication date: 2024-05-24
Anticipated expiration: 2038-11-19
Also published as: CN109445239A

Abstract

The application provides an optical projection module which is used for projecting a preset sensing light spot pattern onto a detected object to perform three-dimensional sensing. The optical projection module comprises a light source, a light splitting element and a light beam modulating element. The light source emits a set of sensing light beams having a preset light field distribution. The beam splitting element divides a group of sensing light beams into at least two groups of sub-light beams which are distributed in the same optical field as the sensing light beams and respectively project onto the light beam modulating element along different directions. The beam modulation element forms a sensing light spot pattern corresponding to each group of sub-beams respectively and projects the sensing light spot pattern onto a measured object. The sensing light spot patterns corresponding to the different groups of sub-beams are identical to each other but have preset position offset. The application also provides a sensing device and equipment.

Description

Optical projection module, sensing device and equipment

Technical Field

The present application relates to optical projection modules, and particularly to an optical projection module, a sensing device and an apparatus.

Background

The existing three-dimensional (Three Dimensional, 3D) sensing module performs three-dimensional sensing by projecting a preset light spot pattern on a measured object. The higher the projected spot density, the more comprehensive the three-dimensional information on the object to be measured can be sensed. The most straightforward way to increase the projected spot density is to increase the number of light emitting points on the light source, which is however limited by the manufacturing process and also increases the manufacturing costs of the light source.

Disclosure of Invention

The application aims to solve the technical problem of providing an optical projection module, a sensing device and equipment, which can increase the density of copy light spots on the basis of not increasing the number of light emitting points of a light source, thereby achieving the beneficial effect of improving the precision of three-dimensional sensing.

The embodiment of the application provides an optical projection module which is used for projecting a preset sensing light spot pattern onto a detected object to perform three-dimensional sensing. The optical projection module comprises a light source, a light splitting element and a light beam modulating element. The light source emits a set of sensing light beams having a preset light field distribution. The beam splitting element divides a group of sensing light beams into at least two groups of sub-light beams which are respectively projected onto the light beam modulating element along different directions. The beam modulation element forms a sensing light spot pattern corresponding to each group of sub-beams respectively and projects the sensing light spot pattern onto a measured object. The sensing light spot patterns corresponding to the different groups of sub-beams are identical to each other but have preset position offset.

In some embodiments, the sensing light spot pattern is formed by copying the light spot pattern of the illuminant of the light source by the light beam modulating element and then combining the copied light spot patterns according to a preset periodicity.

In some embodiments, if the position offset is within the period of a single illuminant spot pattern, the minimum offset by which the position offset is resolved in any direction is greater than or equal to 0.4 times the average of the center-to-center distances of adjacent spots in the spot pattern.

In some embodiments, if the shift of the spot pattern exceeds the range of the single period of the spot pattern of the illuminant, the minimum shift amount of the position shift resolved along any direction still satisfies greater than or equal to 0.4 times of the average value of the center-to-center distances of adjacent spots in the spot pattern after subtracting the product of the size of the single period of the spot pattern of the illuminant along the direction and the number of periods exceeded by the position shift.

In certain embodiments, the light splitting element is selected from one of a prism, a grating, a binary fresnel lens, and combinations thereof.

In some embodiments, the offset overlapping spot patterns have a spot duty cycle in the range of 1.3 times or more and 2 times or less the spot duty cycle of the single spot pattern.

In some embodiments, the light source includes a semiconductor substrate and a light emitter formed on the semiconductor substrate, the light emitter being a vertical cavity surface emitting laser.

In some embodiments, the emitters are arranged on the semiconductor substrate in a manner selected from the group consisting of irregular, regular, periodic, and single-hole broad-sided vertical cavity surface emitting lasers.

The embodiment of the application provides a sensing device for sensing three-dimensional information of a detected object, which comprises a sensing module and the optical projection module according to any one of the above embodiments. The sensing module is used for sensing a preset pattern projected on the detected target object by the optical module and acquiring three-dimensional information of the detected target object by analyzing the image of the preset pattern.

The embodiment of the application provides equipment, which comprises the sensing device. The device executes corresponding functions according to the three-dimensional information of the detected object sensed by the sensing device.

The beam modulation element, the optical projection module, the sensing device and the equipment provided by the embodiment of the application adopt different groups of optical modulation structures to project a plurality of identical light spot patterns which are mutually offset, so that the density of sensing light spots can be increased, and the three-dimensional sensing precision can be improved.

Additional aspects and advantages of embodiments of the application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of embodiments of the application.

Drawings

Fig. 1 is a schematic structural diagram of an optical projection module according to a first embodiment of the present application.

Fig. 2 is a schematic structural diagram of a first light spot pattern formed by the first sub-beams through the beam modulating element in fig. 1.

Fig. 3 is a schematic structural diagram of the first and second spot patterns that are offset and overlapped with each other in fig. 1.

Fig. 4 is a functional block diagram of a sensing device according to a second embodiment of the present application.

Fig. 5 is a schematic structural diagram of a sensing device according to a second embodiment of the present application.

Fig. 6 is a schematic structural view of an apparatus according to a third embodiment of the present application.

Detailed Description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present application and are not to be construed as limiting the present application. In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be interpreted as indicating or implying a relative importance or order of such features. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more of the described feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the description of the present application, it should be noted that, unless explicitly specified or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically connected, electrically connected or communicated with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements or interaction relationship between the two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

The following disclosure provides many different embodiments, or examples, for implementing different structures of the application. In order to simplify the present disclosure, only the components and arrangements of specific examples will be described below. They are, of course, merely examples and are not intended to limit the application. Furthermore, the present application may repeat use of reference numerals and/or letters in the various examples, and is intended to be simplified and clear illustration of the present application, without itself being indicative of the particular relationships between the various embodiments and/or configurations discussed. In addition, the various specific processes and materials provided in the following description of the present application are merely examples of implementation of the technical solutions of the present application, but those of ordinary skill in the art should recognize that the technical solutions of the present application may also be implemented by other processes and/or other materials not described below.

Further, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of embodiments of the application. It will be appreciated, however, by one skilled in the art that the inventive aspects may be practiced without one or more of the specific details, or with other structures, components, etc. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring aspects of the application.

It should be understood that the embodiments and/or methods described herein are exemplary in nature and should not be construed as limiting the scope of the application. The embodiments or methods described herein are only one or more of numerous technical solutions covered by the technical ideas related to the present application, and thus, the steps of the described method technical solutions may be performed in the order indicated, may be performed in other orders, may be performed simultaneously, or may be omitted in some cases, and the above modifications should be regarded as the scope covered by the technical claims of the present application.

Referring to fig. 1, 2 and 3, a first embodiment of the present application provides an optical projection module 1 for projecting a predetermined sensing light spot pattern 11 onto a target object to be detected for three-dimensional sensing. The optical projection module 1 includes a beam modulating element 10, a beam splitting element 11, and a light source 12.

The light source 12 emits a set of sensing light beams 13 having a preset light field distribution. The sensing beam 13 may be a beam with a specific wavelength according to a sensing principle and an application scene. In this embodiment, the sensing beam 13 is used for sensing three-dimensional information of the measured object, and may be an infrared or near-infrared wavelength beam with a wavelength range of 750 nanometers (Nanometer, nm) to 1650nm.

The light source 12 includes a semiconductor substrate 120 and a light emitter 122 formed on the semiconductor substrate 120. The light emitter 122 may be a semiconductor laser. Preferably, in this embodiment, the light emitter 122 is a vertical cavity Surface emitting laser (VERTICAL CAVITY Surface EMITTING LASER, VCSEL), and is fabricated on the semiconductor substrate 120 by photolithography and etching processes. The number of the light emitters 122 may be one or more. The light emitters 122 may be irregularly arranged, regularly arranged, periodically arranged, or single-hole broad-side VCSELs on the semiconductor substrate 120, which is not limited herein. Since the sensing beam 13 is directly emitted by the illuminant 122 of the light source 12, the pattern formed by the sensing beam 13 is an illuminant spot pattern consistent with the arrangement of the illuminant 122 of the light source 12.

The beam splitting element 11 splits a set of sensing beams 13 into at least two sets of sub-beams 130, 132. The internal light field arrangement of each set of sub-beams 130 or 132 is the same as the internal light field arrangement of the sensing beam 13. The different groups of beamlets 130, 132 each project in a different direction. The light-splitting element 11 may be a prism, a grating, a binary fresnel lens, or the like. In the present embodiment, the spectroscopic element 11 is a prism. The projection direction of each group of sub-beams 130 or 132 can be adjusted by changing the parameters of the spectroscopic element 11. The projection direction of each set of sub-beams 130 or 132 should ensure that the beam modulating element 10 covers the entire active working area.

The beam modulating element 10 includes an optical substrate 100 and an optical modulating structure 102 formed on the optical substrate 100. The beam modulating element 10 correspondingly copies each group of sub-beams 130 or 132 according to a preset rule and then combines the sub-beams to form a sensing light spot pattern 11 for three-dimensional sensing, and projects the sensing light spot pattern 11 on a measured object. In this embodiment, the sensing light spot pattern 11 may be formed by combining and arranging the light emitting body light spot patterns 1101 of the light source 12 in a preset period after copying a plurality of copies. The optical modulation structure 102 may be a diffractive optical structure, an optical microlens array, a grating structure, or the like, which can replicate and spread the light beam, which is not limited herein. Correspondingly, the beam modulating element 10 is selected from one of a diffractive optical element (DIFFRACTIVE OPTICAL ELEMENT, DOE), an optical microlens set, a grating, and combinations thereof.

Because the angles of the sub-beams 130, 132 incident on the beam adjustment element 10 are different, the sensing spot patterns 11 formed by the sub-beams 130, 132 passing through the beam adjustment element 10 have a position offset S according to the optical diffraction principle. The positional offset S is related to the angle of incidence between the corresponding different sets of beamlets 130, 132. In this embodiment, the beam splitter 10 splits the sensing beam 13 emitted from the light source 12 into a first sub-beam 130 and a second sub-beam 132. The first sub-beams 130 form corresponding first sensing spot patterns 110 through the beam modulating element 10. The first sensing spot pattern 110 is composed of a plurality of copies of the periodically repeated arrangement of the emitter spot pattern 1101. The second sub-beams 132 form a corresponding second sensing spot pattern 112 by the beam modulating element 10. The second sensing spot pattern 112 is identical to the first sensing spot pattern 110, but the second sensing spot pattern 112 has a predetermined position offset S with respect to the first sensing spot pattern 110. The first and second sensing spot patterns 110 and 112 are planar patterns, so that the mutual positional offset S can be decomposed into a first offset H along a first direction X, which is perpendicular to the second direction Y, and a second offset P along a second direction Y. In this embodiment, the first direction X is a horizontal direction, and the second direction Y is a vertical direction.

If the position offset S is within the period of the single illuminant spot pattern 1101, the minimum offset of the position offset S resolved along any direction is greater than or equal to 0.4 times the average value of the center-to-center distances of adjacent spots in the first sensing spot pattern 110, in this embodiment, the smaller value of the first offset H and the second offset P should be greater than or equal to 0.4 times the average value of the center-to-center distances of adjacent spots. Since the projected spots all have a certain halo range, the spots between the mutually offset sensing spot patterns 11 are as non-overlapping as possible.

The density of the spots in the complete pattern of the first and second sensing spot patterns 110 and 112, which partially overlap after the offset, is increased. If the spot duty ratio of the single sensing spot pattern 11 is T0, the spot duty ratio TN of the complete pattern formed by the first sensing spot pattern 110 and the second sensing spot pattern 112 after offset overlapping is greater than or equal to 1.3 times T0 and less than or equal to twice T0.

It will be appreciated that if the offset of the sensing spot pattern 11 is outside the range of the period of one illuminant spot pattern 1101, the minimum offset of the position offset S resolved in any direction applies to the above-described requirement for the minimum offset and post-overlap spot density of the sensing spot pattern 11 after subtracting an integer multiple of the corresponding period of the size of the individual illuminant spot pattern 1101 in that direction.

It will be appreciated that in other embodiments, the beam splitting element may also split the sensing beam of the light source into more than two different sub-beams to form more than two mutually offset sensing spot patterns 11 by the beam modulating element.

As shown in fig. 1 and 4, a second embodiment of the present application provides a sensing device 4 for sensing three-dimensional information of a measured object. The sensed spatial information of the measured object may be used to identify the measured object or to construct a three-dimensional model of the measured object.

The sensing device 4 includes the optical projection module 1 and the sensing module 2 provided in the first embodiment. The optical projection module 1 is configured to project a preset sensing light spot pattern 11 onto a measured object. The sensing module 2 comprises a lens 21, an image sensor 22 and an image analysis processor 23. The image sensor 22 senses the sensing spot pattern 11 projected onto the object to be measured through the lens 21. The image analysis processor 23 analyzes the sensed sensing light spot pattern 11 to acquire three-dimensional information of the object to be measured.

In this embodiment, as shown in fig. 5, the sensing device 4 is a 3D face recognition device that senses three-dimensional information of the surface of the measured object and recognizes the identity of the measured object according to the three-dimensional information.

The sensing module 4 analyzes three-dimensional information of the surface of the detected object according to the shape change of the preset light spot pattern projected on the detected object by the sensed light spot pattern, and accordingly performs face recognition on the detected object.

As shown in fig. 6, a third embodiment of the present application provides a device 5, such as a mobile phone, a notebook computer, a tablet computer, a touch interactive screen, a door, a vehicle, a robot, an automatic numerical control machine, etc. The apparatus 5 comprises at least one sensing device 4 provided in the second embodiment described above. The device 5 is configured to correspondingly perform a corresponding function according to the sensing result of the sensing means 4. The corresponding functions include, but are not limited to, unlocking after identifying the identity of the user, paying, starting a preset application program, avoiding barriers, and judging any one or more of emotion and health conditions of the user by using a deep learning technology after identifying facial expressions of the user.

In this embodiment, the sensing device 4 is a three-dimensional face recognition device that senses three-dimensional information on the surface of the object to be detected and recognizes the identity of the object to be detected accordingly. The device 5 is an electronic terminal such as a mobile phone, a notebook computer, a tablet computer, a touch interactive screen and the like provided with the three-dimensional face recognition device, or is a device 5 related to access rights such as a door, a vehicle, a security inspection instrument, an access gate and the like.

Compared with the prior art, the beam modulation element 12, the optical projection module 1, the sensing device 4 and the equipment 5 provided by the application adopt different groups of optical modulation structures to project a plurality of identical light spot patterns with mutual position offset, so that the density of sensing light spots can be increased, and the three-dimensional sensing precision can be improved.

In the description of the present specification, reference to the terms "one embodiment," "certain embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing description of the preferred embodiments of the application is not intended to limit the application to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the application.

Claims

1. An optical projection module is used for projecting a preset sensing light spot pattern onto a measured object to perform three-dimensional sensing, the optical projection module comprises a light source, a light splitting element and a light beam modulation element, the light source emits a group of sensing light beams with preset light field distribution, the light splitting element divides the group of sensing light beams into at least two groups of sub-light beams which are respectively projected onto the light beam modulation element along different directions, the light beam modulation element respectively forms a sensing light spot pattern corresponding to each group of sub-light beams and projects the sensing light spot pattern onto the measured object, the sensing light spot patterns corresponding to the different groups of sub-light beams are identical to each other but have preset position offset, the sensing light spot patterns are formed by the light beam modulation element through copying the light spot patterns of the light source according to preset periodic combination, if the position offset is within the period of a single light spot pattern of the light source, the minimum offset of the position offset in any direction is larger than or equal to 0.4 times of the average value of the center distances of adjacent light spots in the light spot patterns, and if the offset of the light spot patterns exceeds the single period of the single period offset in any direction, the position offset of the position offset in any direction is larger than or equal to the average value of the position offset in any direction of the light spot pattern after the position offset in any direction is subtracted from the single position offset of the single light spot pattern in any direction.

2. The optical projection module of claim 1, wherein the light splitting element is selected from one of a prism, a grating, a binary fresnel lens, and combinations thereof.

3. The optical projection module of claim 1, wherein the offset-superimposed spot pattern has a spot duty cycle in a range of 1.3 times or more and 2 times or less the spot duty cycle of the single spot pattern.

4. The optical projection module of claim 1, wherein the light source comprises a semiconductor substrate and a light emitter formed on the semiconductor substrate, the light emitter being a vertical cavity surface emitting laser.

5. The optical projection module of claim 1, wherein the light emitters are arranged on the semiconductor substrate in a manner selected from the group consisting of irregular, regular, periodic, and single-hole broad-sided vertical cavity surface emitting lasers.

6. A sensing device for sensing three-dimensional information of a measured object, comprising a sensing module and the optical projection module according to any one of claims 1 to 5, wherein the sensing module is used for sensing a preset pattern projected by the optical module on the measured object and obtaining the three-dimensional information of the measured object by analyzing an image of the preset pattern.

7. An apparatus comprising the sensing device of claim 6, the apparatus performing a corresponding function based on three-dimensional information of a measured object sensed by the sensing device.