CN211148902U

CN211148902U - Transmitter and distance measurement system

Info

Publication number: CN211148902U
Application number: CN201921631142.2U
Authority: CN
Inventors: 关健; 朱亮; 徐松; 闫敏
Original assignee: Shenzhen Oradar Technology Co Ltd
Current assignee: Shenzhen Oradar Technology Co Ltd
Priority date: 2019-09-27
Filing date: 2019-09-27
Publication date: 2020-07-31
Anticipated expiration: 2029-09-27

Abstract

The utility model discloses a transmitter, which comprises a light source unit, a light source unit and a light source unit, wherein the light source unit is used for transmitting a first light beam; the scanning unit is used for receiving the first light beam and deflecting the first light beam for a certain angle to form a second light beam; the beam splitting unit is used for receiving the second light beam and splitting the second light beam to form a third light beam with more light beams; after a plurality of said deflections, a plurality of said third beams are formed, the resulting projection pattern beam formed by said plurality of third beams having a higher density and/or a larger field angle than the second beam. The beam projection with higher density or larger field angle is realized by the reasonable configuration of the beam-splitting unit and the scanning unit.

Description

Transmitter and distance measurement system

Technical Field

The utility model relates to a computer technology field especially relates to a transmitter and distance measurement system.

Background

The Time of Flight principle (Time of Flight) and the structured light principle are utilized to measure the distance of the target so as to obtain a depth image containing the depth value of the target, and further, the functions of three-dimensional reconstruction, face recognition, man-machine interaction and the like can be realized based on the depth image, and related distance measuring systems are widely applied to the fields of consumer electronics, unmanned driving, AR/VR and the like.

Distance measuring systems based on the time-of-flight principle and the structured light principle generally include a light beam emitter and a light beam collector. A light source in the emitter emits a beam of light toward the target space to provide illumination, and a collector receives the beam of light reflected back by the target. Wherein the time-of-flight distance measuring system calculates the distance of the target object by calculating the time required for the beam to be received from the transmission to the reflection; the structured light distance measuring system processes the reflected light beam pattern and calculates the distance of the target object by using a trigonometry method.

No matter which principle scheme is adopted, the distance measurement system faces some problems to be solved urgently at present, and the most central problems are the problem of measurement resolution, the problem of power consumption and the problem of size.

The measurement resolution is often influenced by the light beam emitted by the emitter, and the denser the emitted light beam is, the resolution is often higher, but the dense light beam has higher requirements on the arrangement density of the light sources and the design requirements of related optical devices, and the dense light beam also means higher power consumption. The difficult problem of power consumption is also influenced by the emitter, and the higher the emitter emits light beam power, the higher the light beam density is, the higher the power consumption is, further, the more widely application of the measurement system in more fields is limited. Secondly, the problem of the volume is often caused by complicated devices in the emitter or collector, for example, the emitter usually includes a light source and some optical elements such as refraction and diffraction, which results in a large volume and is not easy to integrate. Therefore, transmitters are a key problem and providing good transmitters is important to solve the above problems.

The above background disclosure is only for the purpose of assisting understanding of the inventive concept and technical solutions of the present invention, and does not necessarily belong to the prior art of the present patent application, and should not be used for evaluating the novelty and inventive step of the present application in the case that there is no clear evidence that the above content is disclosed at the filing date of the present patent application.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a transmitter and distance measurement system to solve at least one among the above-mentioned background art problem.

In order to achieve the above object, the embodiment of the present invention provides a technical solution that:

a transmitter, comprising: a light source unit for emitting a first light beam; the scanning unit is used for receiving the first light beam and deflecting the first light beam for a certain angle to form a second light beam; the beam splitting unit is used for receiving the second light beam and splitting the second light beam to form a third light beam with more light beams; after a plurality of said deflections, a plurality of said third beams are formed, the resulting projection pattern beam formed by said plurality of third beams having a higher density and/or a larger field angle than the second beam.

In some embodiments, the light source unit further comprises a lens for refracting the light beam emitted by the light source to produce a focusing, collimating or diverging effect.

In some embodiments, the light source unit includes a substrate and at least one sub light source disposed on the substrate, the sub light sources being arranged in a pattern on the substrate.

In some embodiments, the pattern comprises a two-dimensional pattern comprising a regular pattern and/or an irregular pattern.

In some embodiments, the light source unit includes a plurality of sub-light sources, which may be independently controlled in groups.

In some embodiments, the beam splitting unit comprises a diffractive optical element and/or a super-surface optical element.

In some embodiments, the third beam of light has a higher packing density than the second beam of light, and/or the third beam of light has a larger field angle than the second beam of light.

In some embodiments, when the scanning unit deflects an angle smaller than an angle between two adjacent sub-beams in the third beam, the combined projection pattern beam has a higher density than the third beam.

In some embodiments, when the scanning unit deflects at an angle not smaller than a field angle of the third beam, the integrated projection pattern beam has a larger field angle than the third beam.

The utility model discloses a another technical scheme does:

a distance measuring system comprising a transmitter as described in any of the above aspects for transmitting a beam of light towards a target object; the collector is used for collecting at least part of the emitted light beams reflected by the target object and forming light signals; and the processing circuit is connected with the emitter and the collector and calculates the distance of the target object according to the optical signal.

The utility model discloses technical scheme's beneficial effect is:

the utility model discloses a reasonable configuration to beam splitting unit and scanning unit has realized the light beam projection of higher density or bigger angle of vision, can realize finally measuring resolution and the promotion of angle of vision, has solved the problem that measuring resolution is low among the prior art.

Drawings

In order to more clearly illustrate the technical solutions in the present creation or the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the creation, and it is obvious for a person skilled in the art to obtain other drawings according to these drawings without inventive labor.

FIG. 1 is a schematic diagram of a time-of-flight distance measurement system according to one embodiment of the present creation.

Fig. 2 is a schematic diagram of a transmitter according to a first embodiment of the present creation.

FIG. 3 is a schematic diagram of a projection pattern according to a first embodiment of the present disclosure.

Fig. 4 is a schematic diagram of a transmitter according to a second embodiment of the present creation.

Fig. 5 is a schematic diagram of a transmitter according to a third embodiment of the present creation.

FIG. 6 is a schematic diagram of a projection pattern according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram of an integrated beam splitting scanning unit according to one embodiment of the present creation.

FIG. 8 is a schematic diagram of an array light source and its sparse projection pattern according to an embodiment of the present creation.

FIG. 9 is a schematic diagram of an array light source and its dense projection pattern according to an embodiment of the present creation.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the embodiments of the present disclosure more clearly understood, the present disclosure 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 present authoring and are not intended to be limiting.

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 will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, as used herein, refer to an orientation or positional relationship indicated in the drawings, which are based on the orientation or positional relationship shown in the drawings and are used merely to facilitate the description of the inventive embodiments and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be construed as limiting of the present teachings.

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 present embodiments, "a plurality" means two or more unless specifically limited otherwise.

The present creation provides a time-of-flight distance measurement system with higher resolution and/or larger field of view.

Fig. 1 is a schematic view of a time-of-flight distance measurement system according to an embodiment of the present invention. The distance measuring system 10 comprises a transmitter 11, a collector 12 and a processing circuit 13; emitter 11 provides a transmitted light beam 30 into the target space to illuminate object 20 in the space, wherein at least part of transmitted light beam 30 is reflected by object 20 to form a reflected light beam 40, and at least part of the light signals (photons) of reflected light beam 40 are collected by collector 12. Processing circuitry 13 is coupled to emitter 11 and collector 12, and synchronizes the trigger signals of emitter 11 and collector 12 to calculate the time required for the light beam to be emitted from emitter 11 and received by collector 12, i.e. the time of flight t between emitted light beam 30 and reflected light beam 40, and further, the distance D of the corresponding point on the object can be calculated by the following formula:

D＝c·t/2 (1)

where c is the speed of light.

The emitter 11 includes a light source 111, an optical element 112, the light source 111 may be a light source such as a light emitting diode (L ED), an edge emitting laser (EE L), a vertical cavity surface emitting laser (VCSE L), or an array light source composed of a plurality of light sources, preferably, the array light source 111 is a VCSE L array light source chip that generates a plurality of VCSE L light sources on a single semiconductor substrate to form a VCSE L array light source chip, the light beam emitted by the light source 111 may be visible light, infrared light, ultraviolet light, etc. the light source 111 emits a beam of light outwardly under the control of the processing circuit 13, such as in one embodiment, the light source 111 emits a pulsed light beam at a frequency (pulse period) under the control of the processing circuit 13, which may be used in Direct time of flight (Direct TOF) measurements, the frequency being set according to a measurement distance, such as 1MHz-100MHz, and the measurement distance being several meters to several hundred meters.

The optical element 112 receives the pulsed light beam from the light source 111, optically modulates the pulsed light beam, such as by diffraction, refraction, reflection, etc., and then emits the modulated light beam, such as a focused light beam, a flood light beam, a structured light beam, etc., into the space. The optical elements 112 may be in the form of one or more combinations of lenses, diffractive optical elements, super surface (Metasurface) optical elements, masks, mirrors, MEMS mirrors, and the like.

The processing circuit 13 may be a stand-alone dedicated circuit, such as a dedicated SOC chip, an FPGA chip, an ASIC chip, etc., or may comprise a general-purpose processing circuit, for example, when the depth camera is integrated into an intelligent terminal, such as a mobile phone, a television, a computer, etc., the processing circuit in the terminal may be at least a part of the processing circuit 13.

Collector 12 includes a pixel element 121, an imaging lens element 122, wherein the imaging lens element 122 receives and directs at least a portion of the modulated light beam reflected from the object onto the pixel element 121. in one embodiment, the pixel element 121 is composed of a single photon avalanche photodiode (SPAD), or an array pixel element composed of a plurality of SPAD pixels, the array size of the array pixel element representing the resolution of the depth camera, such as 320 × 240, etc. SPAD can respond to the incident single photon to detect the single photon, and can achieve remote and high-precision measurement due to its advantages of high sensitivity, fast response speed, etc. SPAD can count single photons, such as time dependent single photon counting (TCSPC) to achieve collection of weak optical signals and calculation of time of flight, compared to CCD/CMOS, etc. image sensors based on light integration, SPAD can also generally include an integrated circuit (not shown) composed of one or more of signal amplifiers, time-to-digital converters (TDC), ADC), etc. (i.e., the integrated circuit 13 can be considered as a processing circuit).

In some embodiments, the distance measuring system 10 may further include a color camera, an infrared camera, an IMU, etc., and the combination of these devices may realize more abundant functions, such as 3D texture modeling, infrared face recognition, S L AM, etc.

In some embodiments, emitter 11 and collector 12 may be arranged coaxially, i.e. they are implemented by an optical device with reflection and transmission functions, such as a half-mirror.

In the conventional distance measuring system, the emitter 11 is arranged to emit a flood light beam with a certain field angle, which has the advantages of performing a full-range illumination coverage on a measured object, enabling each pixel in the collector 12 to receive the reflected light beam at the same time, and enabling the resolution of the depth image output by the measuring system to be influenced by the resolution of the pixel unit of the collector 12, and the disadvantage is that the power consumption of the emitter 11 is high, and in addition, the interference between adjacent pixels of the collector 11 during synchronous measurement may be caused. In the present invention, therefore, the emitter 11 is arranged to emit the structured light beam outwards, i.e. only a partial area is illuminated in space, and the advantage of using the structured light beam is that the illumination is more concentrated and thus the signal-to-noise ratio is improved, and the disadvantage is that the resolution is lower, and in some cases the disadvantage of insufficient field angle is also present.

Fig. 2 is a schematic diagram of a transmitter according to a first embodiment of the present invention. The emitter comprises a light source unit, a beam splitting unit 204 and a scanning unit 205, the light source unit is used for emitting a first light beam, the beam splitting unit 204 is used for receiving and splitting the first light beam to form a second light beam with a larger number of light beams, the scanning unit 205 is used for receiving and deflecting the second light beam at a certain angle and then emitting a third light beam outwards, a plurality of third light beams are formed after deflection for a plurality of times, and the comprehensive projection pattern light beam formed by the third light beams has higher density and/or larger field angle than the second light beam.

The light source unit comprises a substrate 201 and one or more sub-light sources 202 arranged on the single substrate 201 (or multiple substrates), the sub-light sources 202 are arranged on the substrate in a certain pattern, the substrate 201 can be a semiconductor substrate, a metal substrate and the like, the sub-light sources 202 can be light emitting diodes, edge emitting laser emitters, vertical cavity surface laser emitters (VCSE L) and the like, preferably, the light source unit comprises a semiconductor substrate and an array VCSE L chip formed by a plurality of VCSE L sub-light sources arranged on the semiconductor substrate, the sub-light sources are used for emitting light beams with any required wavelength, such as visible light, infrared light, ultraviolet light and the like, the light source unit emits light under modulation driving of a driving circuit (which can be part of a processing circuit 13), such as amplitude modulation, phase modulation, frequency modulation, pulse modulation and the like, the sub-light sources 202 can also emit light in groups or emit light as a whole under the control of the driving circuit, for example, the sub-light source unit 202 comprises a first sub-light source array 201, a second sub-light source array 202 and the like, the first sub-light source array 201 can also be a regular light source array, a regular light source array can be a regular light source array.

In one embodiment, the light source unit further includes one or more optical elements such as a lens (or a lens group), a micro-lens array, etc., for example, a lens (or a lens group or a combination of a lens group and a micro-lens array) 203 is disposed between the sub-light source 202 and the beam splitting unit 204, and the lens 203 is used for refracting the light beam emitted by the sub-light source to generate focusing, collimating or diverging effect (forming a focused, collimated or diverging first light beam) so as to meet the modulation requirement of the subsequent optical elements.

The beam splitting unit 204 receives a first light beam emitted from a light source and duplicates and splits the first light beam to form a second light beam with a larger number of light beams, in one embodiment, the beam splitting unit 204 duplicates and splits the first light beam to form a second light beam with a higher array density (in the case of a plurality of sub-light sources), in one embodiment, the beam splitting unit 204 duplicates and splits the first light beam to form a second light beam with a larger field angle, such as the embodiment shown in FIG. 3, in one embodiment, the beam splitting unit 204 duplicates and splits the first light beam to form a second light beam with a higher array density and a larger field angle, the beam splitting unit 204 can be one or a combination of more of diffraction optical elements, gratings, optical masks, Metasurface (metasface) optical elements and any optical elements capable of splitting, and for convenience of analysis, the field angle of the second light beam is assumed to be α, and the angular offset of two adjacent sub-light beams in the second light beam is β, and it is noted that if the second light beam is a spatial light beam, both α and β include two directional components (α and α) of the second light beam_x,α_y)、(β_x,β_y)。

After receiving the second light beam from the beam splitting unit 204, the scanning unit 205 deflects and scans the second light beam and emits a third light beam outward. The scanning unit 205 may perform one-dimensional deflection or two-dimensional deflection on each sub-beam of the incident second light beam by diffraction, refraction, reflection, or the like, for example, deflecting along at least one direction by a certain angle θ (θ)_x,θ_y) Fig. 2 schematically shows the scanning unit 205 deflecting the second light beam in a direction by two angles, wherein the first and third light beams 206 can be regarded as being formed by deflecting 0 degrees, and the second and third light beams 207 are formed by deflecting the second light beam by the scanning unit 205 by a smaller angle theta which is smaller than the angle between two adjacent sub-beams in the second light beam, i.e. theta < β, so that the combined projection pattern beam formed by at least two third light beams formed after at least two scans has a higher intensity than the second light beam without the scanning unit 205For example, when the scanning unit 205 is a liquid crystal spatial light modulator, the deflection angle of an incident light beam can be controlled by adjusting the grating period of the arrangement of liquid crystal molecules.

Based on the emitter 11 shown in fig. 2, in one embodiment, the projection pattern formed by the third light beam emitted by the emitter 11 to the target is as shown in fig. 3, in the present embodiment, the beam splitting unit 204 performs a copy beam splitting on the first light beam to form a second light beam with a larger angle of view, in which 3 × 3 is formed, that is, 3 × times copies of the first light beam emitted by the sub-light sources regularly arranged in 3 × 3 are performed to form a second light beam pattern 301 with a large angle of view formed by 9 first light beam patterns 302, the second light beam pattern 301 contains 9 ×: 81 sub-light beams 303, which are indicated by solid line open circles in the figure, assuming that the scanning unit 205 deflects the second light beam, the first deflection is 0 degrees, the formed first third light beam pattern, that is an array spot pattern composed of the solid line open circles 303 in fig. 3, then the scanning unit 205 deflects the second light beam 205, for example, the direction of the second light beam is deflected again, the formed first light beam pattern is composed of solid line open circles 303 in fig. 3, the formed by two adjacent sub-light beam patterns 304, and the scanning beam patterns can be formed by two adjacent sub-beams 304, which are deflected vertically, and the vertical scanning angle of the adjacent sub-beam pattern can be formed by two adjacent sub-beams, which are formed by a half of the vertical deflection angle, which is equal to the vertical deflection angle of the vertical deflection of the second light beam pattern, which is equal to form a scanning beam pattern, which is equal to the same as a scanning angle, that the vertical deflection angle of the vertical deflection of the.

In fact, in the embodiments shown in fig. 2 and 3, the field of view is also increased after the scanning unit 205 deflects the light beam directionThe angle, but the increased field of view is very small relative to the field of view of the second beam formed by the beam splitting unit 204. It can be understood that the density and the angle of field of the projection pattern can be effectively adjusted by reasonably setting the deflection angle. In one embodiment, the deflection angles θ may be sequentially set to

With n scans, the scan angle is increased successively

Thereby increasing the overall projected pattern density by a factor of n. In one embodiment, the deflection angles θ may be sequentially set to

It is thus possible to increase both the density of the projected pattern and the field of view, i.e. the field of view is increased by N β and the density of the intermediate portion overlap region is increased by a factor of N in one embodiment the deflection angle is set to exceed the field of view of the second beam by α, when only the field of view of the projected pattern is increased, as shown in fig. 5.

Fig. 5 is a schematic diagram of an emitter according to a third embodiment of the present invention, which is similar to the embodiment shown in fig. 2 and includes a light source unit composed of a substrate 501, a sub-light source 502 and a lens 503, a beam splitting unit 504 and a scanning unit 505, unlike the embodiment shown in fig. 2, the scanning unit 505 deflects the incident second light beam at a relatively large deflection angle, i.e. θ ≧ α, for example, the first third light beam pattern formed by 0 degree deflection is 506, and after the second deflection α along a certain direction, the second third light beam pattern 507 is formed, the field angle of the integrated projection pattern formed by the first and second third light beam patterns is increased by 2 times along the deflection direction, and the density of the projection pattern is not changed.

In some embodiments, the scanning unit 505 can deflect in multiple directions to form a projection pattern with a larger field angle, such as the projection pattern schematic diagram shown in fig. 6 according to the second embodiment of the present invention, in this embodiment, the light source unit includes 3 × 3 regular arrays of sub-light sources, the beam splitting unit performs 3 × 3 times of replicated beam splitting on the regular arrays of sub-light sources to form 9 × 9 arranged second light beams, the scanning unit deflects in the horizontal and vertical directions 3 times respectively, each time the deflection angle is slightly larger than α (to avoid overlapping of light beams at adjacent boundaries), such as the deflection sequence shown by the arrow in fig. 6, and finally a plurality of third

light beams

602, 603, 604, 605 can be formed, the plurality of third light beams jointly form the projection pattern 601, and the field angle is increased by 2 times in both directions after multiple deflections.

Fig. 4 is a schematic diagram of a transmitter according to a second embodiment of the present invention. The emitter includes light source unit, scanning unit 404 and beam splitting unit 405, and light source unit is used for launching first light beam, and scanning unit 404 is used for receiving and outwards launching the second light beam after deflecting first light beam, and beam splitting unit 405 is used for receiving and forming the third light beam that the light beam quantity is more after splitting to the second light beam. After being deflected for a plurality of times by the scanning unit 404, a plurality of second light beams are formed, and accordingly, the plurality of second light beams are also split by the beam splitting unit to form a plurality of corresponding third light beams, and the combined projection pattern light beams formed by the third light beams have higher density and/or larger field angle than the second light beams.

The light source unit comprises a substrate 401 and one or more sub-light sources 402 arranged on the substrate 401 (or multiple substrates), wherein the sub-light sources 402 are arranged on the substrate in a certain pattern, the substrate 401 can be a semiconductor substrate, a metal substrate and the like, the sub-light sources 402 can be light emitting diodes, edge emitting laser emitters, vertical cavity surface laser emitters (VCSE L) and the like, preferably, the light source unit comprises a semiconductor substrate and an array VCSE L chip formed by a plurality of VCSE L sub-light sources arranged on the semiconductor substrate, the sub-light sources are used for emitting light beams with any required wavelength, such as visible light, infrared light, ultraviolet light and the like, the light source unit emits light under the modulation driving of a driving circuit (which can be a part of a processing circuit 13), such as continuous wave modulation, pulse modulation and the like, the sub-light sources 402 can also emit light in groups or emit light in a whole under the control of the driving circuit, for example, the sub-light source unit comprises a first sub-light source array 401, a second sub-light source array 402 and the like, the first sub-light source array 401 emits light under the control of the first driving circuit can also be arranged under the control of the second sub-light source array, and can be arranged in a regular arrangement, or an irregular arrangement.

In one embodiment, the light source unit further includes one or more optical elements such as a lens (or a lens group), a micro lens array, and the like, for example, a lens (or a lens group) 403 is disposed between the sub-light source 402 and the scanning unit 404, and the lens 403 is used for refracting the light beam emitted from the light source to generate a converging or focusing effect so as to meet the modulation requirement of the subsequent optical elements.

The scanning unit 404 receives a first light beam from the light source, and deflects and scans the first light beam to form a second light beam. The scanning unit 404 may perform one-dimensional deflection or two-dimensional deflection on each sub-beam of the incident second light beam by diffraction, refraction, reflection, or the like, for example, a certain angle along at least one direction, so as to form the second light beam.

The beam splitting unit 405 receives the second light beam from the scanning unit 404 and performs a replicated beam splitting on the second light beam to form a third light beam with a larger number of light beams, in one embodiment, the beam splitting unit 405 performs a replicated beam splitting on the second light beam to form a third light beam with a higher array density, in one embodiment, the beam splitting unit 405 performs a replicated beam splitting on the second light beam to form a third light beam with a larger field of view, in one embodiment, the beam splitting unit 405 performs a replicated beam splitting on the second light beam to form a third light beam with a higher array density and a larger field of view, in one embodiment, the beam splitting unit 405 may be any optical device capable of performing beam splitting, such as a diffractive optical element, an optical mask, a super surface (Metasurface) optical element, and the like in the embodiment shown in fig. 2, by setting a relationship between the deflection angle θ and a field angle α of the third light beam, and an angular offset between adjacent sub-beams to β, a comprehensive projection pattern with a higher density and a larger field of view.

In the embodiment shown in fig. 4, the scanning unit 404 is schematically shown to deflect the first light beam by two angles in one direction, wherein the first and second light beams can be regarded as being formed by deflecting by 0 degrees (shown as a solid line between the scanning unit 404 and the beam splitting unit 405), and the second and second light beams are formed by deflecting the first light beam by a smaller angle θ (shown as a dashed line between the scanning unit 404 and the beam splitting unit 405) by the scanning unit 404, the angle θ is smaller than the included angle θ between two adjacent sub-light beams in the third light beam < β, so that the integrated projection pattern formed by at least two scanning passes through the at least two third

light beams

406 and 407 has a higher density relative to the projection pattern corresponding to the third light beam without the scanning unit 404, thereby increasing the measurement resolution of the measurement system.

In one embodiment, the deflection angles θ may be sequentially set to

With n scans, the scan angle is increased successively

In one embodiment, the deflection angle is set to exceed the viewing angle of the second beam by α, which only increases the viewing angle of the projection pattern, as also shown in FIG. 5, where 504 is the scanning unit and 505 is the beam splitting unit, similarly to the previous analysis, thereby also forming the large field of view projection pattern as shown in FIG. 6。

It can be understood that, in the embodiments shown in fig. 2 and fig. 4, the beam splitting unit and the scanning unit are respectively provided in opposite arrangement to achieve similar functions, in some embodiments, a first beam splitting unit and a second beam splitting unit may be respectively arranged before and after the scanning unit to achieve more complex functions, or a first scanning unit and a second scanning unit may be respectively arranged before and after the beam splitting unit, and similarly, the number and relative position arrangement relationship of the beam splitting unit and the scanning unit may be reasonably set according to actual needs. All falling within the scope of protection of the present invention.

In the above embodiments, the beam splitting unit and the scanning unit are configured reasonably in function to form high-density and/or large-field projection. However, the need to integrate multiple optics into a single emitter creates undoubted manufacturing challenges. To solve this problem, the present invention also provides an integrated beam splitting scanning unit.

Fig. 7 is a schematic diagram of an integrated beam splitting scanning unit according to an embodiment of the present invention. The integrated beam splitting scanning unit can be used in the emitters in the embodiments shown in fig. 1-6, and can also be used in any other desired device. The integrated beam splitting and scanning unit is used for receiving the first light beam, splitting and scanning the light beam to form a third light beam. The integrated beam splitting scanning unit includes a first transparent substrate 701, a second transparent substrate 702, a liquid crystal layer 703, and a beam splitting unit 704 disposed on the first transparent substrate and/or the second transparent substrate. The liquid crystal layer 703 is used to deflect an incident light beam to realize scanning, and the beam splitting unit 704 is used to split the incident light beam. The first transparent substrate 701 and the second transparent substrate 702 may be disposed in parallel and opposite to each other. The liquid crystal layer 703 is installed between the first transparent substrate 701 and the second transparent substrate 702, and the substrates may function to protect the liquid crystal layer. In addition, other functional layers, such as positive and negative electrode layers, can be added in the liquid crystal layer between the two substrates according to requirements, and the positive and negative electrode layers are arranged on two sides of the liquid crystal layer; a polarizing layer or the like may be added to the outer surface or the inner surface of the substrate.

In one embodiment, the integrated beam splitting scanning unit includes a support 705 disposed between the first transparent substrate 701 and the second transparent substrate 702, the support 705 being disposed around the liquid crystal layer to protect the liquid crystal layer while functioning to support the first transparent substrate 701 and the second transparent substrate 702. The support may be made of any material, such as a semiconductor material, an adhesive, etc.

In one embodiment, the beam splitting unit 704 includes one or a combination of diffractive optical elements such as a diffraction grating and a binary grating, and a super surface (Metasurface) optical element, that is, a diffractive optical microstructure and a super surface structure are formed on the surface of a transparent substrate by means of photolithography, etching, and the like, so that high integration of the beam splitting unit and the scanning unit is achieved. The diffractive optical microstructure, the super surface structure, may be formed on a single surface or both surfaces of the first transparent substrate 701 and/or the second transparent substrate according to actual needs. Preferably, the diffractive optical microstructure is formed on an inner surface of a single transparent substrate, which can be effectively protected.

The present creation also provides a method of manufacturing an integrated beam splitting scanning unit, comprising the steps of:

providing a liquid crystal layer for deflecting an incident beam to realize scanning;

providing a first transparent substrate and a second transparent substrate, and generating a beam splitting unit on a single surface or two surfaces of the first transparent substrate and/or the second transparent substrate;

the liquid crystal layer is mounted between the first transparent substrate and the second transparent substrate.

For the integrated beam splitting scanning unit comprising a support, the step of mounting the support between the first transparent substrate and the second transparent substrate and at the periphery of the liquid crystal layer is further included.

For the emitter which deflects the light beam through the scanning unit to realize the large field of view projection (as shown in fig. 5, the positions of the beam splitting unit and the scanning unit are not limited, that is, the beam splitting unit can be arranged in front of the scanning unit or behind the scanning unit), the present invention also provides a dynamic distance measuring system based on the emitter of the grouped array light source. The light source of the emitter in the system comprises an array light source, the sub light sources in the array light source are divided into a plurality of sub light source arrays, each sub light source array can be independently controlled in a grouping mode, in the aspect of spatial arrangement, the sub light source arrays can be arranged in a partitioning mode, namely each sub light source array has an independent spatial partition, the sub light source arrays can also be arranged in a crossing mode, and namely the sub light sources in different sub light source arrays are staggered in the spatial arrangement. At least one sub-light source should be included in the sub-light source array. It can be understood that when the sub-light source arrays are independently turned on, corresponding projection patterns are formed, the density of the projection patterns is related to the density and the number of the sub-light source arrays, the greater the density of the projection patterns corresponding to the sub-light source arrays with more dense arrangement is, and the greater the density of the projection patterns corresponding to the sub-light source arrays with more number is turned on. Based on the large-field-of-view projection scheme (shown in fig. 5) of the grouped array light source, the processing circuit in the measurement system can implement the following dynamic distance measurement method, which specifically includes the following steps:

s1, starting at least one first sub light source array, and forming a sparse projection pattern with a first field of view by using the scanning unit;

fig. 8 is a schematic diagram of an array light source and its sparse projection pattern according to an embodiment of the present invention, the light source in the emitter includes a light source array 801 including a plurality of sub light source arrays, such as a first sub light source array (shown by a hollow circle in fig. 8) and a second sub light source array (shown by a solid circle in fig. 8), the first sub light source array is turned on, and the beam splitting unit and the scanning unit in the emitter respectively split and scan (or scan and split) the light beam emitted by the first sub light source array, and finally emit the light beam in the projection pattern 802 shown on the right side in fig. 8 and enter into a first field area containing a target 804, where the beam splitting unit is schematically shown to perform a copy beam splitting of 2 times of the incident light beam 2 × 2, and the scanning unit sequentially performs a scan of 3 × 3 on the incident light beam to expand the field of view by 3 times in the horizontal and vertical directions, respectively.

S2, obtaining a first depth image with a first resolution, and identifying a region where a target is located; the collector collects the light signals reflected back by the target from the sparse projection pattern beam and is further computed by the processing circuitry to obtain a first depth image of a first resolution corresponding to the sparse projection pattern, and theoretically the depth value of each blob 803 can be obtained, so the depth values of the blobs will constitute the first depth image. The target in the field of view can be identified based on the depth image, for example, a pixel region where the target is located can be identified by any suitable means such as a threshold segmentation method, an edge detection method, a feature identification method, and the like.

S3, starting at least one second sub-light source array, forming a dense projection pattern with a second field of view by using the scanning unit, and calculating a second depth image with a second resolution, wherein the target is identified and located in a pixel region where the target is located in the previous step, the movement of the target is not too large, and the interval between two adjacent measurements is very short, so that the target position is not changed in the time of the two adjacent measurements, therefore, during the measurement, the scanning unit can only form a projection pattern of the second field of view including the target region smaller than the first field of view, and at the same time, more sub-light source arrays can be started than in the step S1 to form a dense projection pattern with a higher relative light beam arrangement density, based on the dense projection pattern, the collector can obtain effective data including more spots of the target to calculate a depth image with a higher resolution, so as to achieve high resolution measurement of only the target region, it can be understood that the resolution refers to the number of effective depth value pixels of the depth values, the number of effective depth value pixels is higher, therefore, the second sub-light source array is higher than the first sub-light source array when the projection pattern is started, such as the projection pattern, when the projection pattern is used in the step 903, the first field of the second field of the projection pattern, the projection pattern is opened, and the projection pattern when the projection pattern, the projection pattern is formed by the projection pattern, such as the projection pattern, when the projection pattern.

It is understood that the above embodiments are described by taking a time-of-flight distance measurement system as an example, but the related transmitter and dynamic distance measurement scheme can be applied to other measurement systems such as a structured light three-dimensional measurement system.

It will be appreciated that when the distance measuring system of the present invention is embedded in a device or hardware, corresponding structural or component changes may be made to adapt it to the needs, and the nature of the system still employs the distance measuring system of the present invention, and therefore should be considered as the scope of the present invention. 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. In the description herein, references to the description of the term "one embodiment," "some embodiments," "preferred embodiments," "an example," "a specific example," or "some examples" or the like are intended to mean 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 invention.

In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction. Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope of the invention as defined by the appended claims.

Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. One of ordinary skill in the art will readily appreciate that the above-disclosed, presently existing or later to be developed, processes, machines, manufacture, compositions of matter, means, methods, or steps, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

1. A transmitter, comprising:

a light source unit for emitting a first light beam;

the scanning unit is used for receiving the first light beam and deflecting the first light beam for a certain angle to form a second light beam;

the beam splitting unit is used for receiving the second light beam and splitting the second light beam to form a third light beam with more light beams;

after a plurality of said deflections, a plurality of said third beams are formed, the resulting projection pattern beam formed by said plurality of third beams having a higher density and/or a larger field angle than the second beam.

2. The transmitter of claim 1, wherein the light source unit further comprises a lens for refracting the light beam emitted by the light source to produce a focusing, collimating or diverging effect.

3. The emitter according to claim 1, wherein said light source unit comprises a substrate and at least one sub-light source disposed on said substrate, said sub-light sources being arranged in a pattern on said substrate.

4. The transmitter of claim 3, wherein the pattern comprises a two-dimensional pattern comprising a regular pattern and/or an irregular pattern.

5. A transmitter as claimed in claim 3, in which the light source unit comprises a plurality of sub-light sources which can be controlled independently in groups.

6. The transmitter of claim 1, wherein the beam splitting unit comprises a diffractive optical element and/or a super-surface optical element.

7. The transmitter of claim 1, wherein the third beam of light has a higher packing density than the second beam of light and/or the third beam of light has a larger field angle than the second beam of light.

8. The transmitter of claim 1, wherein the synthetic projection pattern beam has a higher density than the third beam when the scanning unit is deflected at an angle less than an angle between two adjacent sub-beams in the third beam.

9. The transmitter of claim 1, wherein the synthetic projection pattern beam has a larger field angle than the third beam when the scanning unit is deflected at an angle not less than the field angle of the third beam.

10. A distance measuring system, comprising:

a transmitter as claimed in any one of claims 1 to 9 for transmitting a beam of light towards a target object;

the collector is used for collecting at least part of the emitted light beams reflected by the target object and forming light signals;

and the processing circuit is connected with the emitter and the collector and calculates the distance of the target object according to the optical signal.