A laser light source, an image acquisition device and an electronic device

Abstract

The application provides a laser light source, an image acquisition device and an electronic device, relates to the field of biometric identification technology, and the laser light source encapsulates multiple light emitting elements through an encapsulation space provided by an encapsulation body. By setting the center wavelengths of part of the light emitting elements to be different from each other, the center wavelengths of the part of the light emitting elements are distributed at intervals in the spectrum. In this way, the light emitting spectrum of the laser light source corresponds to a relatively wide region in the spectrum by combining the multiple light emitting elements with different center wavelengths with each other, the light rays with the same wavelength are significantly reduced, and based on the corresponding relationship between the wavelength and the frequency, the light rays with the same frequency can be significantly reduced, so that most of the light rays do not satisfy the condition that the frequencies are the same in the interference condition, the interference phenomenon is reduced, the Newton ring phenomenon caused by the interference is relieved, and the purposes of improving the image imaging quality and the face recognition effect are achieved.

Description

Technical Field

[0001] This application relates to the field of biometric technology, and more specifically, to a laser light source, an image acquisition device, and an electronic device. Background Technology

[0002] With the development of portable terminal devices, such as mobile phones, the application of biometric technology is becoming increasingly widespread and in-depth. Taking electronic devices as an example, fingerprint recognition, fingerprint verification, and facial recognition are increasingly used in screen wake-up of display devices and identity authentication steps in various programs, improving the security of display devices and the flexibility of their use.

[0003] Current facial recognition solutions based on polarization-based 3D imaging technology typically employ lasers as supplementary lighting to provide laser light reflected from the face and received by the camera. However, due to the complexity of the display screen's internal structure, the laser light reflected from the face easily forms transmitted and reflected light as it passes through the screen. Furthermore, given the laser's good coherence, when the transmitted and reflected light meet on the camera's image sensor surface, interference can easily generate Newton's rings, affecting image quality and consequently impacting facial recognition performance. Utility Model Content

[0004] The purpose of this application is to provide a laser light source, an image acquisition device, and an electronic device, addressing the shortcomings of the prior art described above.

[0005] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: In one aspect of this application, a laser light source is provided, including a package with a packaging space and a plurality of light-emitting elements. The plurality of light-emitting elements are disposed within the packaging space, and the package has a light-transmitting area corresponding to the plurality of light-emitting elements. At least some of the light-emitting elements have different center wavelengths.

[0006] Optionally, among the plurality of light-emitting elements, the center wavelengths of any two light-emitting elements with adjacent emission spectra are spaced apart by a preset band, wherein the preset band is less than 5 nm.

[0007] Optionally, the light-emitting element includes a light-emitting unit.

[0008] Optionally, the light-emitting element includes at least two light-emitting units integrally disposed thereon.

[0009] Optionally, some light-emitting elements include one light-emitting unit, while other light-emitting elements include at least two light-emitting units integrally disposed thereon.

[0010] Optionally, the laser source also includes a diffusion element located on the light-emitting side of the multiple light-emitting elements.

[0011] Optionally, the package includes a substrate and a package structure that forms a package space with the substrate, wherein the substrate or package structure has a light-transmitting area corresponding to multiple light-emitting elements.

[0012] Optionally, the light-emitting element is a VCSEL laser chip.

[0013] Optionally, the multiple light-emitting elements are divided into at least two light-emitting groups, and the polarization directions of the linearly polarized light emitted by any two light-emitting groups are different.

[0014] Optionally, the light-emitting element is used to emit linearly polarized light emitted by the light-emitting group to which it belongs; or, the light-emitting group also includes a polarizing element corresponding to the light-emitting element, and the light emitted by the light-emitting element is modulated by the polarizing element to form linearly polarized light emitted by the light-emitting group.

[0015] Optionally, the first electrodes of all light-emitting elements of the laser light source are connected, and the second electrodes of all light-emitting elements in the same light-emitting group are connected.

[0016] Optionally, at least two light-emitting groups may have their light-emitting elements distributed in a mixed manner.

[0017] Optionally, all the light-emitting elements of the laser source are arranged in rows and columns to form a light-emitting array; In the row and / or column directions of the light-emitting array, at least one light-emitting element from another light-emitting group is disposed between two adjacent light-emitting elements in the same light-emitting group.

[0018] Optionally, in the light-emitting array, the light-emitting elements of at least two light-emitting groups are arranged alternately in the row direction and / or column direction.

[0019] Optionally, all the light-emitting elements of the laser source are arranged in rows and columns to form a light-emitting array; The same group of light-emitting elements is arranged in the row direction of the light-emitting array, and at least two groups of light-emitting elements are arranged alternately in the column direction of the light-emitting array; or, the same group of light-emitting elements is arranged in the column direction of the light-emitting array, and at least two groups of light-emitting elements are arranged alternately in the row direction of the light-emitting array.

[0020] Optionally, the light-emitting array can be a rectangular array or a circular array.

[0021] Optionally, the linearly polarized light emitted by at least two light-emitting groups is in the infrared band. In another aspect of the embodiments of this application, an image acquisition device is provided, including an image receiver and any of the above-mentioned laser light sources, wherein the laser light source and the image receiver are arranged sequentially along the optical path.

[0022] Optionally, the image receiver includes a photosensitive unit array and a polarization device. At least two linearly polarized lights emitted by the laser source are reflected by the target object and then sequentially incident on the photosensitive unit array through the polarization device. The polarization direction of the polarization device is the same as one of the polarization directions of the linearly polarized lights emitted by the laser source.

[0023] In another aspect of the embodiments of this application, an electronic device is provided, including a display screen and an image acquisition device of any of the above, wherein the image acquisition device is located below the display screen.

[0024] Optionally, the polarization device of the image acquisition device is at a 45-degree angle to the polarization direction of the linear polarizer of the display screen, or the polarization direction of the polarization device of the image acquisition device is parallel to the fast axis or slow axis of the quarter-wave plate of the display screen.

[0025] The beneficial effects of this application include: This application provides a laser source, an image acquisition device, and an electronic device. The laser source encapsulates multiple light-emitting elements within the encapsulation space provided by a package. By setting the center wavelengths of some of the light-emitting elements to be different, the center wavelengths of these elements are distributed at intervals in the spectrum. By combining multiple light-emitting elements with different center wavelengths, the emission spectrum of the laser source corresponds to a wider region of the spectrum. Because the wavelength range of the light emitted by the laser source is distributed over a wider range in the spectrum, compared to multiple lasers having the same and narrower emission spectrum, the amount of light of the same wavelength is significantly reduced. Based on the correspondence between wavelength and frequency, the amount of light of the same frequency can be significantly reduced, thus ensuring that most light does not satisfy the condition of the same frequency in interference, reducing interference phenomena, alleviating the Newton's rings phenomenon caused by interference, and improving image imaging quality and face recognition performance. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the optical path for generating Newton's rings when multiple lasers with the same and narrow emission spectra are applied to under-screen imaging. Figure 2 The image formed after a camera captures a picture of a piece of white paper; Figure 3 This is one of the structural schematic diagrams of a laser source provided in the embodiments of this application; Figure 4 This is a schematic diagram of the emission spectrum corresponding to a light-emitting group provided in an embodiment of this application; Figure 5 This is one of the structural schematic diagrams of a light-emitting element provided in the embodiments of this application; Figure 6 This is a second schematic diagram of the structure of a light-emitting element provided in an embodiment of this application; Figure 7 This is the third schematic diagram of the structure of a light-emitting element provided in the embodiments of this application; Figure 8 This is a second schematic diagram of the structure of a laser source provided in an embodiment of this application; Figure 9 for Figure 8 A cross-sectional view of the laser source shown; Figure 10 This is the third schematic diagram of a laser source provided in the embodiments of this application; Figure 11 This is the fourth schematic diagram of a laser source provided in the embodiments of this application; Figure 12 Fifth schematic diagram of a laser source provided in the embodiments of this application; Figure 13 This is a schematic diagram of the structure of an image acquisition device provided in an embodiment of this application; Figure 14 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0028] Icons: 10-Laser light source; 11-Light emission group; 110-Light emission element; 111-Light emission unit; 113-First light emission element; 114-Second light emission element; 121-Substrate; 122-Packaging structure; 130-Diffuser element; 20-Face; 30-Image receiver; 31-Photosensitive unit array; 32-Polarization device; 41-Middle frame; 42-Display screen. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] Currently, in under-display facial recognition solutions based on polarization 3D imaging technology, supplementary lighting is required as the light source for facial recognition. When selecting the type of supplementary lighting, considering the relatively high manufacturing costs of LED light sources in packaging and other processes, lasers are typically chosen as the supplementary lighting in current facial recognition solutions.

[0031] Having established that the laser possesses good coherence, the following explanation addresses the reason for the formation of Newton's rings due to interference: Please refer to... Figure 1 Multiple lasers emit narrow and identical emission spectra, thus their emitted laser light is concentrated within a narrow spectral range. When the laser light is reflected by a face, it enters the interior of display screen 1. A portion of the laser light is directly transmitted out of display screen 1 (referred to as the first beam 3), while the other portion, due to the complexity of the internal structure of display screen 1, is obstructed by certain layers of the display screen 1 (e.g., ...). Figure 1 The first ray 3 and the second ray 4 are reflected multiple times by the display pixel substrate and pixel electrode 2 on the back side of the display screen 1, and then transmitted out of the display screen 1. When the first ray 3 and the second ray 4 meet on the surface of the image sensor 6 of the camera 5, Newton's rings are generated due to interference, which affects the image quality and thus the face recognition effect. Figure 2 Using white paper as an example, the image formed after camera 5 captures the white paper is shown. It can be seen from the image that the obvious Newton's rings (ring texture) affect the clarity of the white paper in the image.

[0032] In order to mitigate the adverse effects of using the laser as a supplementary light, one aspect of this application provides a laser source, including a package with a packaging space and a plurality of light-emitting elements. The plurality of light-emitting elements are disposed within the packaging space, and the package has a light-transmitting area corresponding to the plurality of light-emitting elements. At least some of the light-emitting elements have different center wavelengths.

[0033] By setting the center wavelengths of some light-emitting elements to be different, the center wavelengths of these elements are distributed at intervals in the spectrum. By combining multiple light-emitting elements with different center wavelengths, the emission spectrum of the laser source corresponds to a broader region of the spectrum, distinguishing it from... Figure 1 The corresponding lasers have the same and relatively narrow emission spectra.

[0034] Based on this, when a laser light source participates in under-screen polarization 3D imaging, the linearly polarized light emitted by the laser source is reflected by the target object and reaches the image receiver through the display screen. At this time, because the wavelength range corresponding to linearly polarized light has a wider distribution range in the spectrum, compared to multiple lasers having the same and narrower emission spectrum, the amount of light with the same wavelength is significantly reduced. Based on the correspondence between wavelength and frequency, the amount of light with the same frequency can be significantly reduced, thus ensuring that most light does not satisfy the condition of the same frequency in the interference condition. This reduces interference phenomena, alleviates the Newton's rings phenomenon caused by interference, and improves image quality and facial recognition performance.

[0035] For ease of understanding, the term "light-emitting group" appearing in this application is described as follows: all light-emitting elements of a laser light source are divided into at least two light-emitting groups, that is, each light-emitting group is a collection of at least one light-emitting element.

[0036] Figure 3 This is one of the structural schematic diagrams of a laser source provided in the embodiments of this application. Figure 4 This is a schematic diagram of the emission spectrum of a light-emitting group provided in an embodiment of this application. Figure 3 The two light-emitting groups 11 shown are both related to Figure 4 The emission spectrum shown corresponds to the emission spectrum. Figure 3 The image shows the light-emitting group 11 included in the laser light source 10, and the light-emitting element 110 included in the light-emitting group 11.

[0037] The light-emitting group 11 may include at least one light-emitting element 110.

[0038] When the light-emitting group 11 includes at least two light-emitting elements 110, and among all the light-emitting elements 110 included in the light-emitting group 11, there are at least two light-emitting elements 110 with different center wavelengths, the light-emitting group 11 is called a broadband light-emitting group 11.

[0039] In all the light-emitting groups 11 included in the laser light source 10, if at least one light-emitting group 11 is a broadband light-emitting group 11, the laser light source 10 can reduce interference phenomena by means of the broadband light-emitting group 11, alleviate the Newton's rings phenomenon caused by interference, and achieve the purpose of improving image imaging quality and face recognition effect.

[0040] To facilitate understanding, let's continue with... Figure 3 This application is illustrated as follows: Figure 3 The diagram shows two light-emitting groups 11, both of which are broadband light-emitting groups 11. Each broadband light-emitting group 11 includes 18 light-emitting elements 110, of which 9 light-emitting elements 110 have different center wavelengths. Figure 4The emission spectrum of one broadband light-emitting group 11 is given, which contains nine light-emitting elements 110 with different center wavelengths, namely, light-emitting elements 110 with center wavelengths of 920nm, 925nm, 930nm, 935nm, 940nm, 945nm, 950nm, 955nm, and 960nm from left to right. Therefore, the emission spectrum of this broadband light-emitting group 11 can be equivalent to... Figure 4 The equivalent spectrum shown by the dashed line is from Figure 4 It can be seen that the equivalent spectrum of the entire broadband luminescent group 11 occupies a relatively wide range in the spectrum, compared to Figure 1 The corresponding multiple lasers have the same narrow emission spectrum (e.g., only lasers with a center wavelength of 920nm) which is significantly broader. This also means that the light emitted by the broadband light-emitting group 11 includes multi-wavelength light from 920nm to 960nm. Only a very small portion of these light rays have the same frequency. After passing through the complex structure and complex light path involved in under-screen 3D imaging, only a very small portion of these light rays (which can be ignored) may have the conditions for interference. This alleviates the Newton's rings phenomenon caused by interference, thereby improving image quality and face recognition performance.

[0041] It should be understood that the more light-emitting groups 11 included in the laser source 10, the more effectively the adverse effects caused by interference can be mitigated. Therefore, in actual setup, an appropriate number of light-emitting groups 11 can be selected as broadband light-emitting groups 11 according to requirements. This application does not limit the number of broadband light-emitting groups 11; for example, a portion of all light-emitting groups 11 can be used as broadband light-emitting groups 11, or all light-emitting groups 11 can be used as broadband light-emitting groups 11.

[0042] To illustrate this, we take the example of all light-emitting groups 11 being broadband light-emitting groups 11: When the laser light source 10 is applied to three-dimensional polarization imaging technology, different broadband light-emitting groups 11 can be controlled to be lit in a certain order, and the lighting cycles of different broadband light-emitting groups 11 are staggered, so that at most one broadband light-emitting group 11 is lit at the same time, ensuring that the image receiver 30 can only receive the light emitted by one broadband light-emitting group 11 at the same time, and cannot receive the light from the other broadband light-emitting groups 11. Based on this control method (which can also be used when some of the light-emitting groups 11 are broadband light-emitting groups 11), when one broadband light-emitting group 11 is lit (while the rest are off), it emits linearly polarized light in one polarization direction. This light is then reflected by the target object and received by the image receiver 30, resulting in an image. The lit broadband light-emitting group 11 is then turned off, and the next broadband light-emitting group 11 is lit, emitting linearly polarized light in another polarization direction, until the next image is obtained. By sequentially lighting and photographing in this manner, an image can be obtained each time a broadband light-emitting group 11 is lit. Based on the foregoing description, since the light source for each image formation is a broadband light-emitting group 11, the quality of each image can be effectively improved.

[0043] To be more specific, the more light-emitting elements 110 in the broadband light-emitting group 11 that have different center wavelengths, the better the adverse effects caused by interference can be mitigated. Therefore, in actual installation, an appropriate number of light-emitting elements 110 can be selected according to requirements to ensure that they all meet the requirement of different center wavelengths. This application does not limit the number of light-emitting elements 110 in the broadband light-emitting group 11 that meet the requirement of different center wavelengths. For example, it can be that some of all light-emitting elements 110 meet the requirement of different center wavelengths, or it can be that all light-emitting elements 110 have different center wavelengths.

[0044] To illustrate this, consider an example where all the light-emitting elements 110 in the broadband light-emitting group 11 have different center wavelengths: When the broadband light-emitting group 11 is lit, all the light-emitting elements 110 contained therein are excited, and each light-emitting element 110 emits a beam of linearly polarized light. Therefore, multiple light-emitting elements 110 can emit multiple beams of linearly polarized light (with the same polarization direction) as the linearly polarized light emitted by the broadband light-emitting group 11. Moreover, the wavelengths of any two beams of linearly polarized light are not exactly the same, thus enabling the linearly polarized light emitted by the broadband light-emitting group 11 to cover a relatively wide range of the spectrum.

[0045] Of course, when the broadband light-emitting group 11 contains a large number of light-emitting elements 110, although having all the light-emitting elements 110 in the broadband light-emitting group 11 with different center wavelengths can better mitigate the Newton's rings phenomenon, the cost is also relatively high. Therefore, in some solutions, while mitigating the adverse effects caused by Newton's rings to meet the requirements and taking cost into consideration, only a portion of all the light-emitting elements 110 in the broadband light-emitting group 11 can meet the requirement of different center wavelengths. A more specific explanation is as follows: Please refer to Figure 3 Each broadband light-emitting group 11 contains 18 light-emitting elements 110. The center wavelengths of the nine light-emitting elements 110 in the left three columns of the same broadband light-emitting group 11 are all different. The remaining nine light-emitting elements 110 in the right three columns are equivalent to copies of the nine light-emitting elements 110 in the left three columns. In other words, among the 18 light-emitting elements 110 in the broadband light-emitting group 11, there are nine different center wavelengths, and there are two light-emitting elements 110 with the same center wavelength. This construction of the broadband light-emitting group 11 can create a wider emission spectrum using nine light-emitting elements 110 with different center wavelengths, thus mitigating the adverse effects of Newton's rings. It can also supplement brightness requirements with the other nine light-emitting elements 110 while avoiding an excessive number of center wavelength types, thereby reducing costs.

[0046] It should be understood that when all the light-emitting elements 110 in the distributed laser source 10 are distributed, the light-emitting elements 110 with the same center wavelength can be evenly distributed or clustered.

[0047] Based on the foregoing description, from the perspective of emission spectrum, the broadband light-emitting group 11 can be equivalent to a broadband light source. To make the broadband light-emitting group 11 more equivalent, the center wavelength interval between any two adjacent light-emitting elements 110 in the broadband light-emitting group 11 can be a small band. For example, in some possible embodiments, in at least one broadband light-emitting group 11, the center wavelength interval between any two adjacent light-emitting elements 110 is a preset band, which is less than 5 nm.

[0048] After understanding the relationship between the light-emitting group 11 and the light-emitting element 110, the specific structure of the light-emitting element 110 will be explained below: The light-emitting element 110 includes at least one light-emitting unit 111, wherein the light-emitting unit 111 is the smallest unit in the light-emitting element 110 with independent light-emitting capability. For example, when the light-emitting element 110 is a VCSEL (Vertical Cavity Surface Emitting Laser) laser chip, the light-emitting unit 111 is the smallest light-emitting unit in the VCSEL laser chip. The optical resonant cavity is at least part of the light-emitting unit 111. Under electrical excitation, the optical resonant cavity is used to repeatedly reflect photons to excite more atomic transitions and release more photons of the same frequency and phase. In other words, the light inside the light-emitting element 110 is generated in the optical resonant cavity and finally emitted from the light-emitting window (also called the optical aperture, which refers to a specific area in the laser structure designed to allow photons to escape, which can be a circular or square opening) on ​​one side of the optical resonant cavity. Therefore, a light-emitting unit 111 has a single or independent light-emitting window.

[0049] Of course, a light-emitting element 110 may include any number of light-emitting units 111, such as Figure 5 As shown, the light-emitting element 110 includes a light-emitting unit 111 and has a light-emitting window. After the light-emitting element 110 is lit, a beam of light is emitted outward from the light-emitting window. Figure 6 As shown, the light-emitting element 110 includes two light-emitting units 111 with two spaced light-emitting windows. After the light-emitting element 110 is lit, a beam of light is emitted outward from each light-emitting window. Figure 7 As shown, the light-emitting element 110 includes four light-emitting units 111 and has four spaced light-emitting windows. After the light-emitting element 110 is lit, a beam of light is emitted outward from each light-emitting window.

[0050] It should be understood that all light-emitting units 111 in the light-emitting element 110 share the same substrate (also called the substrate) so that they can be integrally formed. For example, in mass production, a large number of light-emitting units 111 can be formed in the same wafer; when the light-emitting element 110 has only a single light-emitting unit 111 (such as... Figure 5 The light-emitting element 110 is formed into separate light-emitting units 111 through a cutting process; when the light-emitting element 110 has two or more light-emitting units 111 (e.g. Figure 6 or Figure 7 ), can be directly cut into units of all light-emitting units 111 of the same light-emitting element 110 (e.g., by Figure 6 Cut into units of two light-emitting units 111 or in order to Figure 7The light-emitting elements 110 are cut into units of four light-emitting units 111. In this way, the different light-emitting elements 110 after cutting can be separated from each other, but all the light-emitting units 111 in the same light-emitting element 110 are not separated from each other and still share the same substrate. In this way, the gap between all the light-emitting units 111 in the light-emitting element 110 is very small or almost non-existent, which can further miniaturize the overall volume of the light-emitting element 110. Especially when it is applied to the under-display hole-punch scenario, it can further reduce the hole diameter and increase the screen ratio.

[0051] Since the light-emitting element 110 may include an unlimited number of light-emitting units 111, it has the following multiple grouping methods: The first type: In the same light-emitting group 11, all light-emitting elements 110 have one light-emitting unit 111; The second type: In the same light-emitting group 11, all light-emitting elements 110 have two or more light-emitting units 111, and they are integrated into one unit, that is, they share the same substrate as mentioned above. The third type: The light-emitting elements 110 in the same light-emitting group 11 are divided into two parts. One part of the light-emitting elements 110 has one light-emitting unit 111, and the other part of the light-emitting elements 110 has two or more light-emitting units 111, and they are integrated into one unit, that is, they share the same substrate as mentioned above.

[0052] As mentioned earlier, when the light-emitting group 11 is applied to polarization 3D imaging, it needs to emit linearly polarized light. Different light-emitting groups can emit linearly polarized light with different polarization directions to meet the requirements of 3D imaging. To enable the light-emitting group 11 to emit linearly polarized light with the desired polarization direction, the light-emitting element 110 within the light-emitting group 11 can directly emit linearly polarized light, or the light-emitting element 110 can first emit natural light and then form linearly polarized light through a polarization element. Specifically: One illustration is that the light-emitting element 110 can be equipped with a structure that generates and selects the polarization state, such as a Brewster window or an intracavity polarizer, or the anisotropy of the gain medium inside the light-emitting element 110 can be used to make the light emitted from the light-emitting element 110 itself have linearly polarized light with the desired polarization direction.

[0053] Another illustration: The light-emitting element 110 itself does not directly emit linearly polarized light, but first emits natural light or unpolarized light, and then by adding a polarizing element outside the light-emitting element 110 in its light-emitting path, the natural light or unpolarized light is adjusted in polarization state by the polarizing element to form linearly polarized light that conforms to the expected polarization direction.

[0054] To facilitate the excitation of light emitted from the light-emitting units 111 in the light-emitting element 110, electrodes are provided on the light-emitting units 111 to apply excitation. Each light-emitting unit 111's electrode can be divided into a first electrode and a second electrode. When the electrodes of the light-emitting unit 111 are externally connected, the first electrodes of all light-emitting elements 110 in the laser source 10 can be connected together, and the second electrodes of all light-emitting elements 110 in the same light-emitting group 11 can be connected together. The second electrodes of light-emitting elements 110 in different light-emitting groups 11 are not connected. This allows the second electrodes to control the different light-emitting groups 11 to be lit in a predetermined order, such as satisfying the aforementioned requirement: the lighting cycles of different broadband light-emitting groups 11 are staggered, so that at most one broadband light-emitting group 11 is lit at any given time.

[0055] In order to make the light emitted by the laser source 10 to the target area more uniform, in some optional embodiments, the laser source 10 further includes a diffusion element 130, which is located on the light-emitting side of all light-emitting groups 11. In this way, the linearly polarized light emitted by each light-emitting group 11 can be diffused and homogenized by the diffusion element 130 before being emitted to the target area.

[0056] When the laser light source 10 includes a package, it is usually used as a packaged light source. Of course, in another possible implementation, the laser light source can also be used as an unpackaged light source. Taking a packaged light source as an example: the package can encapsulate all the light-emitting elements of the laser light source. For example, the package includes a substrate 121 and a package structure 122 that forms a package space with the substrate 121. All the light-emitting groups 11 are located in the package space. The substrate 121 or the package structure 122 has a light-transmitting area corresponding to all the light-emitting groups 11, so that the linearly polarized light emitted by the light-emitting groups 11 can be smoothly propagated outward through the light-transmitting area.

[0057] In some alternative embodiments, the diffusion element 130 may be part of the encapsulation structure 122, in which case the light-transmitting area of ​​the encapsulation structure 122 is located in the diffusion element 130.

[0058] In some alternative implementations, the packaging structure 122 may be a ceramic package.

[0059] In some alternative implementations, when the light-emitting element 110 is a VCSEL laser chip, it includes, but is not limited to, top-emitting and bottom-emitting types.

[0060] For the broadband light-emitting group 11, there are light-emitting elements 110 with different center wavelengths. When fabricating light-emitting elements 110 with different center wavelengths, the center wavelength can be controlled by one or a combination of the following methods: The first method involves changing the coating design in the light-emitting element 110 (light-emitting unit 111) (such as changing the number of layers or materials of the mirrors on both sides of the quantum well) to selectively enhance or unify the characteristic wavelength, thereby creating light-emitting elements 110 (light-emitting unit 111) with different center wavelengths.

[0061] The second method involves controlling the cavity mode wavelength by adjusting the optical thickness of the optical resonator (such as the number of mirror layers or the position of the quantum well).

[0062] The third method involves designing units with different aperture sizes, which can emit different spectra.

[0063] Based on the foregoing description, when the light-emitting group 11 is applied to polarization three-dimensional imaging, the light-emitting group 11 can emit linearly polarized light. Furthermore, the linearly polarized light emitted by different light-emitting groups 11 has different polarization directions, thus allowing differentiation between different light-emitting groups 11 based on the polarization direction of the emitted linearly polarized light. Regarding the distribution of the light-emitting elements 110 of different light-emitting groups 11, the light-emitting elements 110 of different light-emitting groups 11 can be arranged in a "group-based concentrated distribution" manner. In other words, the light-emitting elements 110 of the same light-emitting group 11 are concentrated in one area, while the light-emitting elements 110 of different light-emitting groups 11 are concentrated in different areas according to the group distinction. For example… Figure 3 As shown, there are two light-emitting groups 11. The light-emitting elements 110 of one light-emitting group 11 are concentrated in the upper half of the region, and the light-emitting elements 110 of the other light-emitting group 11 are concentrated in the lower half of the region. In this way, when the laser light source 10 is lit, the light-emitting group in the upper half of the region can be lit while the light-emitting group 11 in the lower half of the region remains off. Then, the light-emitting group 11 in the upper half of the region is off while the light-emitting group 11 in the lower half of the region is lit.

[0064] When arranged in this "group-based centralized distribution" manner, the illumination effect of the linearly polarized light emitted by different light-emitting groups 11 on the target area will vary to some extent. For example, in terms of the illuminated area: the illuminated area of ​​the linearly polarized light emitted by different light-emitting groups 11 may differ slightly; in terms of light intensity: when an optical film layer is provided on the light-emitting side of all light-emitting groups 11 of the laser source 10, the transmittance of the optical film layer at different positions may vary due to deviations in the manufacturing process. This difference will ultimately affect the light intensity of the linearly polarized light emitted by different light-emitting groups 11 illuminating the target area. Specifically, for example... Figure 3As shown, a diffusion element 130 is provided on the light-emitting side of the two light-emitting groups 11 in the upper and lower halves. Due to deviations in the manufacturing process, the transmittance of the diffusion element 130 in the upper and lower halves may be different. As a result, the light loss generated when the linearly polarized light emitted by the light-emitting group 11 in the upper half passes through the upper half of the diffusion element 130 and the light loss generated when the linearly polarized light emitted by the light-emitting group 11 in the lower half passes through the lower half of the diffusion element 130 will also be different. This will result in different light intensities in the target area, and the two images obtained will be different in brightness. This is not conducive to the subsequent reconstruction of the three-dimensional contour surface of the target by analyzing the differences between the two images.

[0065] To mitigate this adverse effect, at least two light-emitting groups 11 of the laser light source 10 can be mixed and distributed together, resulting in a distribution characteristic where light-emitting elements 110 from other light-emitting groups 11 are distributed between at least two light-emitting elements 110 within the same light-emitting group 11. This mixed distribution method can improve the difference in illumination effect of linearly polarized light emitted from different light-emitting groups 11 in the target area.

[0066] It should be understood that the more light-emitting groups 11 involved in the mixed distribution, the better this improvement effect. For example, all light-emitting groups 11 are mixed and distributed among themselves. Figure 8 and Figure 9 The diagram shows two light-emitting groups 11, namely a first light-emitting group 11 and a second light-emitting group 11, wherein the first light-emitting group 11 includes a plurality of first light-emitting elements 113 ( Figure 8 (Solid frame, 18 in total), the second light-emitting group 11 includes multiple second light-emitting elements 114 ( Figure 8 (The dashed box contains 18 elements in total). The light-emitting elements 110 of the two light-emitting groups are mixed and distributed to form an interlaced distribution effect. This makes the overlap of the illuminated areas formed by the first light-emitting group 11 and the second light-emitting group 11 higher. When setting the optical film layer (such as the diffuser element 130), both can correspond to the positions of the optical film layer with deviation, thereby weakening the influence of the transmittance difference of different positions of the optical film layer on the light intensity.

[0067] When the light-emitting groups 11 of the laser source 10 are mixed and distributed, all the light-emitting elements 110 in the distributed laser source 10 can be arranged in an array. Utilizing the regularity of the array arrangement, the light output effect can be improved and the circuit design complexity reduced. For ease of understanding, the array arrangement forms will be described below: Example 1 All light-emitting elements 110 of the laser source 10 are arranged in an array to form a light-emitting array, wherein the light-emitting elements 110 are arranged in rows and columns. In the row direction and / or column direction of the light-emitting array, at least one light-emitting element 110 from another light-emitting group 11 is disposed between two adjacent light-emitting elements 110 in the same light-emitting group 11. For example, please refer to... Figure 8 The 36 light-emitting elements 110 shown are divided into a first light-emitting group 11 and a second light-emitting group 11, and the 36 light-emitting elements 110 are distributed in 6 rows and 6 columns. Among them, there is a second light-emitting element 114 in the second light-emitting group 11 between two adjacent first light-emitting elements 113 in the first light-emitting group 11.

[0068] More specifically, optionally, in the light-emitting array, the light-emitting elements 110 of at least two light-emitting groups 11 are arranged alternately in the row direction and / or column direction. For example, please refer to... Figure 8 The first light-emitting element 113 of the first light-emitting group 11 and the second light-emitting element 114 of the second light-emitting group 11 are arranged alternately in the row direction (i.e., in an ABAB arrangement). Simultaneously, the first light-emitting element 113 of the first light-emitting group 11 and the second light-emitting element 114 of the second light-emitting group 11 are also arranged alternately in the column direction. This allows for a more uniform mixing degree between the first light-emitting group 11 and the second light-emitting group 11, facilitating the absorption of transmittance differences at different locations within the optical film layer. Ultimately, this results in the first light-emitting group 11 and the second light-emitting group 11 forming similar illuminated areas and light intensities in the region where the target object is located.

[0069] Example 2 All light-emitting elements 110 of the laser source 10 are arranged in an array to form a light-emitting array, wherein the light-emitting elements 110 are arranged in rows and columns. Light-emitting elements 110 of the same light-emitting group 11 are arranged in the row direction of the light-emitting array, and in the column direction of the light-emitting array, light-emitting elements 110 of at least two light-emitting groups 11 are arranged alternately. For example, please refer to... Figure 10 The 36 light-emitting elements 110 shown are divided into a first light-emitting group 11 and a second light-emitting group 11, and the 36 light-emitting elements 110 are distributed in 6 rows and 6 columns. The first light-emitting elements 113 of the first light-emitting group 11 are distributed in rows 1, 3, and 5, and the second light-emitting elements 114 of the second light-emitting group 11 are distributed in rows 2, 4, and 6. This can absorb the difference in transmittance of different positions of the optical film layer from the column direction, so that the illuminated area and light intensity formed by the first light-emitting group 11 and the second light-emitting group 11 in the area where the target object is located are similar.

[0070] Example 3 All light-emitting elements 110 of the laser source 10 are arranged in an array to form a light-emitting array, wherein the light-emitting elements 110 are arranged in rows and columns. Light-emitting elements 110 of the same light-emitting group 11 are arranged in the column direction of the light-emitting array, and in the row direction of the light-emitting array, light-emitting elements 110 of at least two light-emitting groups 11 are arranged alternately. For example, please refer to... Figure 11 The 36 light-emitting elements 110 shown are divided into a first light-emitting group 11 and a second light-emitting group 11, and the 36 light-emitting elements 110 are distributed in 6 rows and 6 columns. The first light-emitting element 113 of the first light-emitting group 11 is distributed in columns 1, 3, and 5, and the second light-emitting element 114 of the second light-emitting group 11 is distributed in columns 2, 4, and 6. This allows the absorption of the transmittance difference of different positions of the optical film layer in the row direction, so that the illuminated area and light intensity formed by the first light-emitting group 11 and the second light-emitting group 11 in the area where the target object is located are similar.

[0071] In some alternative implementations, the light-emitting array is a rectangular array or a circular array. For example... Figure 8 , Figure 10 and Figure 11 As shown, the light-emitting arrays are all rectangular arrays, for example... Figure 12 As shown, the light-emitting array is a circular array.

[0072] In some alternative implementations, the linearly polarized light emitted by at least two light-emitting groups 11 is in the infrared band, which can reduce the sensitivity of the human eye.

[0073] In some alternative implementations, the number of light-emitting elements contained in different light-emitting groups is equal.

[0074] In some alternative implementations, the only difference between the different light-emitting groups is the polarization direction of the emitted linearly polarized light.

[0075] In some alternative embodiments, the laser source includes two light-emitting groups, so that the two light-emitting groups can emit linearly polarized light with two polarization directions, and the polarization directions of the two linearly polarized lights are perpendicular to each other, such as linearly polarized light with a polarization direction of 0 degrees and linearly polarized light with a polarization direction of 90 degrees, or linearly polarized light with a polarization direction of 45 degrees and linearly polarized light with a polarization direction of 135 degrees.

[0076] Furthermore, in a light-emitting array, at least some adjacent light-emitting elements (satisfying that the polarization directions of the emitted linearly polarized light are different) have the same center wavelength or emission spectrum. This ensures that light-emitting elements with the same emission spectrum in different light-emitting groups are located close to each other, thus minimizing differences caused by position. For example... Figure 8 In the middle, there are 6 light-emitting elements in the row direction, belonging to different light-emitting groups. From left to right, every two light-emitting elements meet the condition that their center wavelength or emission spectrum is the same.

[0077] In another aspect of the embodiments of this application, an image acquisition device is provided, including an image receiver 30 and a laser light source 10 of any of the above.

[0078] To facilitate understanding, let's first provide an overview of the principle behind polarization-based 3D imaging using image acquisition devices: Linearly polarized light has the following characteristics: When linearly polarized light propagates to the surface of a target object and is reflected by the target object, the polarization state of each ray in the linearly polarized light changes. The amount of change in the polarization state of each ray is related to the material of the target object's surface where the ray is incident and the angle of incidence (spatial position) of each point on the target object's contour surface. Please refer to... Figure 13 The light-emitting group 11 emits linearly polarized light toward the face 20 (target object). Utilizing the aforementioned characteristics of linearly polarized light, and based on the spatial differences in the points on the contour surface of the face 20 (the incident angle of linearly polarized light differs at different points) and the surface material of the face 20, the linearly polarized light reflected by the face 20 carries polarization information corresponding to the contour surface of the face 20. Subsequently, it is received sequentially by the image receiver 30 according to the incident order. Thus, the image receiver 30 generates multiple polarized images sequentially based on their incident order. Since the polarization directions of each linearly polarized light are different, the depth information of the face 20 can be obtained by analyzing the differences between multiple polarized images. Based on this, the contour surface of the face 20 can be reconstructed more accurately, which helps to achieve high-precision face 20 recognition.

[0079] It should be understood that the images can be used for face recognition, including face matching and / or anti-spoofing identification. Face matching refers to whether the face to be verified is the same person as a pre-recorded correct face in the database (generally determined by calculating similarity). The correct face is also called a face template or database image. Anti-spoofing identification refers to whether the face to be verified is a real face or a forgery such as a photo, video, or silicone face mold. Of course, when the target object is changed to a hand, gesture imaging, vein and palm print imaging, etc., can also be performed.

[0080] The image receiver 30 includes a photosensitive unit array 31 and a polarizing device 32. The photosensitive unit array 31 is located on the light-emitting side of the polarizing device 32. This means that linearly polarized light, after being reflected by the target object, passes through the polarizing device 32 before entering the photosensitive unit array 31. Furthermore, the polarization direction of the polarizing device 32 has the following relationship with the laser source 10: the polarization direction of the polarizing device 32 forms an angle smaller than a preset range with one of the polarization directions of the linearly polarized light emitted by the laser source 10, for example, an angle of 0 degrees, meaning the two polarization directions are the same. This allows the image receiver 30 to receive more information from some linearly polarized light and less information from other linearly polarized light, thereby creating the expected differentiation of information from different linearly polarized light.

[0081] In another aspect of the embodiments of this application, an electronic device is provided, such as... Figure 14 As shown, the device includes a main body and any of the above-mentioned image acquisition devices, with the image acquisition device disposed on the main body.

[0082] The aforementioned electronic devices may specifically include mobile phones, tablets, televisions, laptops, smart home devices (such as smart air conditioners, smart refrigerators, smart speakers, smart lights or smart curtains, etc.), wearable electronic devices, in-vehicle devices (also known as vehicle infotainment systems), virtual reality devices, etc., and this application does not impose any restrictions on them.

[0083] For example Figure 14 As shown, a mobile phone is illustrated, which includes a main body and the aforementioned image acquisition device. The main body includes a back panel, a mid-frame 41, a motherboard, a battery, and a display screen 42. The back panel and the display screen 42 are respectively mounted on opposite sides of the mid-frame 41 so that the three enclose an internal space. The motherboard and the battery can be located within this internal space. The battery is used to power the motherboard, the image acquisition device, and the display screen 42. The display screen 42 has a cutout portion, and the cutout position is aligned with the position of the laser light source 10 and the image receiver 30 in the image acquisition device.

[0084] To achieve better display effects, the display screen 42 typically incorporates a linear polarizer and / or a quarter-wave plate. Considering that the linear polarizer and quarter-wave plate within the display screen 42 correspond to its display wavelength, typically the visible light band, for easy human perception, when the laser source 10 of the image acquisition device is in the infrared band, the linearly polarized light emitted will experience phase delay as it passes through the linear polarizer or quarter-wave plate within the display screen 42. This alters the polarization direction and intensity of the linearly polarized light, which is detrimental to polarized 3D imaging. To mitigate this issue, in some alternative embodiments, the polarization device 32 of the image acquisition device forms a 45-degree angle with the polarization direction of the linear polarizer of the display screen 42, or the polarization direction of the polarization device 32 is parallel to the fast or slow axis of the quarter-wave plate of the display screen 42. This minimizes the influence of the linear polarizer or quarter-wave plate within the display screen 42 on the linearly polarized light emitted by the laser source 10.

[0085] In the description of this application, the target object can be the face 20 in the accompanying drawings, or a part of the face 20 (such as cheeks, nose, and eyes). Of course, it is not limited to this, and can also be other objects with three-dimensional dimensions, such as fingers, palms, etc.

[0086] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0087] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0088] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0089] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0090] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A laser light source, characterized in that, The package includes a package with a packaging space and a plurality of light-emitting elements disposed within the packaging space. The package has a light-transmitting area corresponding to the plurality of light-emitting elements, and at least some of the light-emitting elements have different center wavelengths.

2. The laser source as described in claim 1, characterized in that, Among the plurality of light-emitting elements, the center wavelengths of any two light-emitting elements with adjacent emission spectra are separated by a preset wavelength band, wherein the preset wavelength band is less than 5 nm.

3. The laser source as described in claim 1, characterized in that, The light-emitting element includes a light-emitting unit; Alternatively, the light-emitting element may include at least two light-emitting units integrally disposed thereon; Alternatively, some of the light-emitting elements may include one light-emitting unit, while other parts of the light-emitting elements may include at least two light-emitting units integrally disposed thereon.

4. The laser source as described in claim 1, characterized in that, The light-emitting element is a VCSEL laser chip.

5. The laser source as described in claim 1, characterized in that, The laser source also includes a diffusion element, which is located on the light-emitting side of the plurality of light-emitting elements.

6. The laser source as described in claim 1, characterized in that, The package includes a substrate and a package structure that forms the package space in conjunction with the substrate. The substrate or the package structure has a light-transmitting area corresponding to the plurality of light-emitting elements.

7. The laser light source according to any one of claims 1 to 6, characterized in that, The plurality of light-emitting elements are divided into at least two light-emitting groups, and the polarization directions of the linearly polarized light emitted by any two of the light-emitting groups are different.

8. The laser source as described in claim 7, characterized in that, The light-emitting element is used to emit linearly polarized light emitted by the light-emitting group to which it belongs; Alternatively, the light-emitting group may further include a polarizing element corresponding to the light-emitting element, wherein the light emitted by the light-emitting element is modulated by the polarizing element to form linearly polarized light emitted by the light-emitting group.

9. The laser source as described in claim 7, characterized in that, The first electrodes of all light-emitting elements of the laser light source are connected, and the second electrodes of all light-emitting elements of the same light-emitting group are connected.

10. The laser source as described in claim 7, characterized in that, At least two of the light-emitting groups have their light-emitting elements mixed and distributed together.

11. The laser source as described in claim 10, characterized in that, All the light-emitting elements of the laser light source are arranged in rows and columns to form a light-emitting array; In the row direction and / or column direction of the light-emitting array, at least one light-emitting element from another light-emitting group is disposed between two adjacent light-emitting elements in the same light-emitting group.

12. The laser source as described in claim 11, characterized in that, In the light-emitting array, the light-emitting elements of the at least two light-emitting groups are arranged alternately in the row direction and / or column direction.

13. The laser source as described in claim 10, characterized in that, All the light-emitting elements of the laser light source are arranged in rows and columns to form a light-emitting array; The light-emitting elements of the same light-emitting group are arranged in the row direction of the light-emitting array, and the light-emitting elements of the at least two light-emitting groups are arranged alternately in the column direction of the light-emitting array; or, the light-emitting elements of the same light-emitting group are arranged in the column direction of the light-emitting array, and the light-emitting elements of the at least two light-emitting groups are arranged alternately in the row direction of the light-emitting array.

14. The laser source as described in claim 11 or 13, characterized in that, The light-emitting array is a rectangular array or a circular array.

15. An image acquisition device, characterized in that, It includes an image receiver and a laser source as described in any one of claims 1 to 14, wherein the laser source and the image receiver are arranged sequentially along the optical path.

16. An electronic device, characterized in that, It includes a display screen and an image acquisition device as described in claim 15; the image acquisition device is located below the display screen.

17. The electronic device as claimed in claim 16, characterized in that, The polarization device of the image acquisition device forms a 45-degree angle with the polarization direction of the linear polarizer of the display screen, or the polarization direction of the polarization device of the image acquisition device is parallel to the fast axis or slow axis of the quarter-wave plate of the display screen.

Images