A uniform light illumination module

Abstract

The application discloses a light-uniform illuminating module, which has the advantages of good light-emitting uniformity and high light energy utilization rate. The light guide module is in a table body structure, and has opposite upper and lower end faces and a through hole penetrating through the upper and lower end faces in the axial direction of the table body, the through hole being located in the center of the table body; the upper and lower end faces are connected through the side face of the table body; the side face of the table body comprises an inner side face of the through hole close to the central axis of the through hole and an outer side face of the table body away from the central axis of the through hole; the outer side face of the table body is the light-incident face of the light guide module; the upper end face is the light-emitting face of the light guide module; the light guide module is installed on a module base; the light source module comprises a plurality of light-emitting units, and the plurality of light-emitting units are coaxially and symmetrically installed in the light source installation area of the module base with the central axis of the through hole as the axis; part of the light beams emitted by the light-emitting units passes through the light-incident face of the light guide module and is emitted from the light-emitting face of the light guide module, and part of the light beams is directly emitted without passing through the light guide module.

Description

Technical Field

[0001] This application relates to the fields of biometric identification and three-dimensional imaging, specifically to a uniform illumination module. Background Technology

[0002] With the development of science and technology and industry, the payment field has gradually upgraded to mobile payment in recent years. Breakthroughs and iterations in biometric identification and 3D imaging technologies have made the diversified development of mobile payment possible. Currently, the mainstream biometric identification technologies used in identity authentication scenarios include facial recognition, palm print recognition, and palm vein recognition, with the biometric identification system being one of the most crucial modules.

[0003] Biometric identification systems typically include an illumination module, an imaging module, and a controller module. The illumination module projects infrared or visible light onto the target object. After being reflected by the target object, the infrared or visible light image carrying biometric information is received by the imaging module, thereby identifying the target object's facial information, palm print information, or palm vein information.

[0004] However, when the target object is close to the biometric identification system, the high illuminance of the infrared or visible light projected by the illumination module, coupled with weaker illuminance at the center and corners and poor uniformity, leads to overexposure and poor image quality in the infrared or visible light images received by the imaging module. Simultaneously, the infrared receiving camera lens in the imaging module causes the corners of the infrared image to be even darker, further degrading its quality. Poor-quality infrared images result in low accuracy, low recognition rate, and poor noise resistance in biometric identification. Therefore, improving the uniformity of light output from the illumination module is crucial for enhancing the accuracy, recognition rate, and noise resistance of biometric identification. Summary of the Invention

[0005] This application provides a uniform light illumination module, which can achieve the purpose of improving light output uniformity and light energy utilization.

[0006] According to a first aspect of this application, a uniform illumination module is provided, the module comprising: a light source module, a light guide module, and a module base;

[0007] The light guide module has a platform structure that is wider at the top and narrower at the bottom. The light guide module has an upper end face, a lower end face, and a through hole that penetrates the upper end face and the lower end face along the axial direction of the platform. The through hole is located at the center of the platform.

[0008] The upper end face and the lower end face are connected by the side of the platform body; wherein, the side of the platform body includes the inner side of the through hole near the central axis of the through hole and the outer side of the platform body away from the central axis of the through hole; the outer side of the platform body is the light-incident surface of the light guide module; the upper end face is the light-outceasing surface of the light guide module; the light guide module is mounted on the module base;

[0009] The light source module includes multiple light-emitting units, which are coaxially and symmetrically mounted in the light source mounting area of ​​the module base with the central axis of the through hole as the axis; each light-emitting unit includes at least an infrared light-emitting unit.

[0010] Part of the light beam emitted by the light-emitting unit passes through the light-incident surface of the light guide module and is emitted from the light-out surface of the light guide module to the target object, while part of the light beam is emitted directly to the target object without passing through the light guide module.

[0011] The technical solution of this application sets the light guide module as a platform structure that is wider at the top and narrower at the bottom. The upper surface of the platform structure is set as the light-emitting surface of the light guide module, and the outer surface of the platform structure is set as the light-incident surface of the light guide module. This controls the light-emitting unit in the light source mounting area of ​​the module base to pass through the light-incident surface of the light guide module and then exit from the light-emitting surface of the light guide module to the target object, while the remaining light beams exit directly to the target object without passing through the light guide module. This improves the uniformity of light output and the light energy utilization rate of the uniform illumination module. Using the uniform illumination module provided in this application embodiment to supplement the illumination of the imaging module for biometric identification can ensure uniform illumination at the center and four corners of the imaging module, which is beneficial to improving the imaging quality of the imaging module and improving the accuracy, recognition rate, and noise resistance of biometric identification. Furthermore, the uniform illumination module provided in this application embodiment also has the advantages of being easy to manufacture, easy to install and fix, and low in cost.

[0012] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1(a) is a side view of a uniform illumination module in an exploded state according to an embodiment of this application;

[0015] Figure 1(b) is a side view of a uniform illumination module in a combined state according to an embodiment of this application;

[0016] Figure 2(a) shows an installation method of the light source module on the module base when the light guide module provided according to the embodiment of this application is a frustum structure;

[0017] Figure 2(b) shows another mounting method of the light source module on the module base when the light guide module provided according to the embodiment of this application is a frustum structure;

[0018] Figure 3(a) is a side view of another uniform illumination module in an exploded state according to an embodiment of this application;

[0019] Figure 3(b) is a side view of another uniform illumination module in a combined state according to an embodiment of this application;

[0020] Figure 4(a) shows an installation method of the light source module on the module base when the light guide module provided according to the embodiment of this application has a frustum structure;

[0021] Figure 4(b) shows another installation method of the light source module on the module base when the light guide module provided according to the embodiment of this application has a frustum structure;

[0022] Figure 5(a) is a side view of another uniform illumination module in an exploded state according to an embodiment of this application;

[0023] Figure 5(b) is a side view of another uniform illumination module in a combined state according to an embodiment of this application;

[0024] Figure 6 This is one method of mounting the light source module on the module base when the light guide module provided in the embodiment of this application has a truncated quadrangular structure;

[0025] Figure 7 This is a schematic diagram of another uniform illumination module structure in an exploded state according to an embodiment of this application;

[0026] Figure 8 This is a cross-sectional view of another uniform illumination module in a combined state according to an embodiment of this application;

[0027] Figure 9 This is a schematic diagram of the structure of an infrared light-emitting unit provided according to an embodiment of this application;

[0028] Figure 10 This is another way to install the light source module on the module base according to the embodiments of this application. Detailed Implementation

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

[0030] It should be noted that the terms "first," "second," "target," and "candidate," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] Example 1

[0032] This embodiment can be applied to scenarios where a biometric identification system is used to identify target objects, such as identity authentication, and where a uniform lighting module is used for supplemental lighting.

[0033] The uniform lighting module provided in this application includes a light source module, a light guide module, and a module base. The light guide module is a frustum structure that is wider at the top and narrower at the bottom. Optionally, the frustum structure can be a truncated cone structure or a truncated pyramid structure. The truncated pyramid structure can be a regular truncated pyramid structure or a quadrangular truncated pyramid structure.

[0034] For ease of understanding, the structure of the uniform lighting module is shown below, taking the case where the light guide module has a frustum structure as an example. Figures 1(a) and 1(b) are side views of a uniform lighting module according to an embodiment of this application; Figures 2(a) and 2(b) are top views of a uniform lighting module according to an embodiment of this application.

[0035] Furthermore, Figure 1(a) is a structural exploded view of the uniform illumination module, and Figure 1(b) is a structural assembly view of the uniform illumination module.

[0036] Figure 2(a) shows one way the light source module is installed on the module base, and Figure 2(b) shows another way the light source module is installed on the module base.

[0037] The light guide module 102 shown in Figures 1(a) and 1(b), as well as Figures 2(a) and 2(b), is a frustum structure that is wider at the top and narrower at the bottom. The light guide module 102 has opposing upper and lower end faces along the axial direction of the frustum, and a through hole penetrating both the upper and lower end faces, with the through hole located at the center of the frustum. When the light guide module has a frustum structure, the upper and lower end faces are annular, and the through hole penetrating both end faces is cylindrical.

[0038] Optionally, the substrate of the light guide module 102 is made of a light-diffusing material with high transmittance and low absorbance, such as PMMA (Polymethylmethacrylate), PC (Polycarbonate), PET (Polyethyleneterephthalate), etc. In order to balance optical effect and processing cost, the light guide module 102 is processed by 3D printing.

[0039] The upper end face is the light-emitting surface 1022 of the light guide module, and the upper end face and the lower end face are connected by the side of the stage body; wherein, the side of the stage body includes the inner side of the through hole 1023 near the central axis of the through hole and the outer side of the stage body away from the central axis of the through hole; the outer side of the stage body is the light-incident surface 1021 of the light guide module.

[0040] The distance between the upper and lower end faces is the first height H1; the distance between the inner side of the through hole and the central axis of the through hole is the second radius R2; the distance between the upper edge of the outer side of the platform and the central axis of the through hole is the third radius R3, and the distance between the lower edge of the outer side of the platform and the central axis of the through hole is the fourth radius R4; wherein, the third radius is greater than the fourth radius, i.e., R3 > R4; wherein, the first radius is generally smaller than the third radius, i.e., R3 > R1. The angle between the lower end face of the light guide module and the outer side of the platform is the first included angle θ1.

[0041] Optionally, the light-incident surface 1021 of the light guide module is generally a transparent, smooth surface with extremely high transmittance; the light-exiting surface 1022 of the light guide module is generally a frosted surface, which has a certain scattering effect. After the light reaches the light-exiting surface, the frosted surface scatters the light, which can improve the light uniformity of the uniform illumination module. The smooth or frosted surface is obtained through processes such as polishing and sandblasting.

[0042] The light guide module 102 is mounted on the module base. The light guide module 102 also includes a light guide fixing component, which is used to fix the light guide module 102 to the module base. The light guide module and the light guide fixing component are integrally formed. Optionally, the light guide module and the light guide fixing component are obtained by 3D printing. Using integral molding technology to manufacture the light guide module and the light guide fixing component has the advantages of easy processing and production, easy installation and fixing, and low cost. Mounting the light guide module on the module base using the light guide fixing component minimizes lateral displacement under installation errors and prevents axial movement. Simultaneously, rotation of the light guide module 102 along its circumference also does not produce axial movement, thus improving the assembly stability of the light guide module.

[0043] The module base includes a light source board, which is shown as 103 in Figures 1(a) and 1(b) and Figures 2(a) and 2(b). The light source board of the module base has a light source mounting area for mounting a light source module, which is shown as 101 in Figures 1(a) and 1(b) and Figures 2(a) and 2(b). The light source mounting area is parallel to the plane containing the lower end face of the light guide module, located away from the light guide module, and the light source faces the upper end face.

[0044] Referring again to Figures 2(a) and 2(b), the light source module 101 includes N light-emitting units 1011, which are coaxially and symmetrically mounted in the light source mounting area of ​​the module base with the central axis O of the through hole as the axis. Here, N refers to the number of light-emitting units, and N is a positive integer. Optionally, the multiple light-emitting units 1011 are mounted uniformly or non-uniformly in the light source mounting area of ​​the module base. Uniformity and non-uniformity refer to whether the spacing between any two adjacent light-emitting units is consistent; if the spacing is consistent, it is uniform; otherwise, it is non-uniform.

[0045] Figure 2(a) illustrates the case where N=6, i.e., there are 6 light-emitting units 1011, showing the situation where N light-emitting units are evenly installed on the module base. In Figure 2(a), the 6 light-emitting units 1011 are coaxially and symmetrically installed in the light source mounting area of ​​the module base with the central axis O of the through hole as the axis according to the first radius R1 and the first spacing L1, forming a coaxial ring lighting. The first spacing L1 is the spacing between any two adjacent light-emitting units.

[0046] Figure 2(b) shows the case where N=4, i.e., there are 4 light-emitting units 1011, illustrating the situation where N light-emitting units are non-uniformly installed on the module base. As shown in Figure 2(b), the 4 light-emitting units 1011 are coaxially and symmetrically installed in the light source mounting area of ​​the module base with the central axis O of the through hole as the axis, and the spacing between any two adjacent light-emitting units is different.

[0047] N light-emitting units are coaxially, symmetrically, and uniformly installed in the light source mounting area of ​​the module base with the central axis O of the through hole as the axis, and the emitted light illuminance of the light-emitting units is proportional in the length and width directions; multiple light-emitting units are coaxially, symmetrically, and non-uniformly installed in the light source mounting area of ​​the module base with the central axis O of the through hole as the axis, and the emitted light illuminance of the light-emitting units is different in the length and width directions.

[0048] Using the light source module mounting method shown in Figure 2(a), the emitted light reaching the infrared receiving camera is a circular spot with uniform illumination at the center and corners, suitable for infrared receiving camera imaging chips with a symmetrical aspect ratio. Using the light source module mounting method shown in Figure 2(b), the emitted light reaching the infrared receiving camera is an elliptical spot with uniform illumination at the center and corners, making the spot more suitable for infrared receiving camera imaging chips with different aspect ratios. Both light source module mounting methods avoid illumination differences caused by spacing and position variations, improving the uniformity of light output from the illumination module and increasing light energy utilization.

[0049] It is worth noting that the cases of 6 and 4 light-emitting units shown in Figures 2(a) and 2(b) are for illustrative purposes only and do not limit the number of light-emitting units. The number of light-emitting units is determined according to the actual situation and is not limited here.

[0050] The light-emitting unit includes at least one infrared light-emitting unit; these infrared light-emitting units form an infrared supplementary lighting array. The infrared supplementary lighting array is used to project uniform infrared light. The infrared light-emitting unit can be any of the following: a vertical-cavity surface-emitting laser (VCSEL), a horizontal cavity surface-emitting laser (HCSEL), an edge-emitting laser (EEL), or an LED. Each infrared light-emitting unit consists of one or more light-emitting points, which can be distributed regularly or randomly. The wavelength is selected from the infrared band, typically 850nm, 905nm, or 940nm, for emitting infrared light.

[0051] Optionally, the uniform illumination module can be used in biometric identification scenarios. In these scenarios, the light source module mounted on the module base is electrically connected to the controller module in the biometric identification system. The controller module is also electrically connected to the imaging module in the biometric identification system.

[0052] Optionally, the controller module includes a logic control module, and the imaging module includes a camera module.

[0053] Correspondingly, the light source module installed on the module base is electrically connected to the logic control module in the controller module, and the logic control module in the control module is electrically connected to the camera module in the imaging module.

[0054] The logic control module controls whether the light source module in the uniform illumination module emits light and whether the uniform illumination module projects uniform infrared light. The camera module in the imaging module is located at the through-hole of the light guide module. The camera module is typically an infrared receiving camera, used to acquire speckle infrared or floodlight infrared images of the target object, such as a face or palm, under the uniform infrared light projected by the uniform illumination module. The infrared receiving camera faces the same side as the light source. The logic control module also controls whether the camera module in the imaging module operates and its operating mode.

[0055] To ensure that the uniform illumination module has a large target emission angle, high light uniformity within the emission angle range, and uniform illumination at the center and four corners of the light spot reaching the infrared receiving camera in the imaging module, it is necessary to design the number of light-emitting units N, the first spacing L1, the first radius R1, the second radius R2, the third radius R3, the fourth radius R4, the first height H1, and the first included angle θ1 in the uniform illumination module.

[0056] First, to ensure uniform illumination of the uniform lighting module, a portion of the light beam emitted by the light-emitting unit 1011 passes through the light-incident surface 1021 of the light guide module and exits from the light-exit surface 1022 of the light guide module to the target object, while the remaining portion of the light beam exits directly to the target object without passing through the light guide module 102. Specifically, controlling the first included angle θ1 to be less than the half-intensity angle of the light-emitting unit allows a portion of the light beam from the light-emitting unit 1011 to exit directly to the target object. The half-intensity angle of the light-emitting unit is the angle range in the intensity distribution of the light beam that, when it spreads outwards along the normal direction of the light source center of the light-emitting unit, the central light intensity drops to half of its peak value.

[0057] Secondly, the divergence angle of the N light-emitting units 1011 in the light source module of the uniform lighting module is all The emission angle corresponding to the ray coinciding with the surface normal of the light-emitting unit is defined as 0°. At the divergence angle... Within a light source, the smaller the exit angle, the greater the corresponding illuminance and the higher the uniformity of the illuminance. The uniformity of illuminance is generally characterized by the ratio of the minimum illuminance to the maximum illuminance in the luminous plane.

[0058] To ensure uniform light emission from all emission angles within the target emission angle of the uniform illumination module, the emitted light from the N light-emitting units in the light source module needs to overlap before being emitted into the light guide module. Specifically, this requires that adjacent light-emitting units can overlap their light fields, the illuminance uniformity at the overlap point should be as consistent as possible, and the overlap point should intersect with the light-incident surface of the light guide module.

[0059] In Figures 2(a) and 2(b), the dashed circles surrounding the light-emitting unit 1011 represent the cross-sectional view of the light spot illuminating the light guide module. Since there are relatively few light-emitting units in Figures 2(a) and 2(b), the effect of overlapping light fields is not shown.

[0060] Based on the above requirements and the luminous characteristics of a single light-emitting unit, at the target emission angle of the uniform illumination module, the position of the light field overlap point can be determined, and thus the position of the light-incident surface in the light guide module can be selected. Then, according to the laws of light refraction and scattering, the number of light-emitting units N, the first spacing L1, the first radius R1, the second radius R2, the third radius R3, the fourth radius R4, the first height H1, and the first included angle θ1 that meet the uniform illumination requirements of the uniform illumination module can be determined.

[0061] Finally, the light guide module of the uniform lighting module can perform secondary distribution of the light emitted from the light source module onto the incident light surface.

[0062] In traditional structures, the light guide module of the uniform illumination module is a cylindrical structure or a uniform light sheet structure. As a result, the light projected by the uniform illumination module reaches the center and four corners of the infrared receiving camera in the imaging module with weak illumination, which will cause the four corners of the infrared light image formed by the infrared receiving camera to be darker, affecting the imaging quality of the imaging module.

[0063] This application designs the light guide module of the uniform illumination module as a platform structure, controlling the vertical distance between the lower and upper end faces as a first height H1, and designing the distance between the inner side of the through hole and the central axis of the through hole as a second radius R2. Part of the light beam emitted by the light-emitting unit 1011 is controlled to be emitted directly to the target object without passing through the light guide module 102, while part of the light beam passes through the light-incident surface 1021 of the light guide module, and after refraction and scattering by the light guide module, is scattered from the light-exit surface 1022 of the light guide module before being emitted to the target object. Based on the laws of light refraction and scattering, under the condition that part of the light beam after refraction and scattering by the light guide module concentrates towards the center and four corners, the first height H1 and the second radius R2 can be determined. For example, the first height H1 is typically 3mm to 10mm.

[0064] The technical solution of this application sets the light guide module as a platform structure that is wider at the top and narrower at the bottom. The upper surface of the platform structure is set as the light-emitting surface of the light guide module, and the outer surface of the platform structure is set as the light-incident surface of the light guide module. Part of the light beam emitted by the light-emitting unit in the light source mounting area of ​​the module base passes through the light-incident surface of the light guide module and is emitted from the light-emitting surface of the light guide module to the target object, while part of the light beam is emitted directly to the target object without passing through the light guide module. The uniform illumination module provided in this application, by setting the light guide module as a platform structure that is wider at the top and narrower at the bottom, not only allows the light-incident surface of the light guide module to redistribute part of the light beam emitted by the light source module, which is beneficial to improving the uniformity of light output of the uniform illumination module, but also has the advantages of easy processing and production, easy installation and fixation, and low cost. Using the uniform illumination module provided in this application embodiment to supplement the imaging module for biometric identification can make the illumination at the center and four corners of the light spot reaching the imaging module uniform, which is beneficial to improving the imaging quality of the imaging module and improving the accuracy, recognition rate, and noise resistance of biometric identification.

[0065] Example 2

[0066] This embodiment proposes another structure for the uniform illumination module based on the above embodiments. This application embodiment shows the case where the light guide module has a frustum structure. Next, referring to Figures 3(a) and 3(b), and Figures 4(a) and 4(b), the other structure of the uniform illumination module will be elaborated.

[0067] Figures 3(a) and 3(b) are side views of another uniform lighting module provided according to an embodiment of this application. Figures 4(a) and 4(b) are top views of another uniform lighting module provided according to an embodiment of this application. Further, Figure 3(a) is an exploded view of the uniform lighting module, and Figure 3(b) is an assembled view of the uniform lighting module. Figure 4(a) shows one mounting method of the light source module on the module base, and Figure 4(b) shows another mounting method of the light source module on the module base.

[0068] In Figures 3(a) and 3(b) and Figures 4(a) and 4(b), 301, 302 and 303 represent the light source module, the light guide module and the light source board in the module base, respectively.

[0069] Unlike the embodiments described above, in the uniform illumination module shown in Figures 3(a) and 3(b) and Figures 4(a) and 4(b), the light guide module 302 has a frustum structure, the through hole penetrating the upper and lower end faces has a prism structure, and the upper and lower end faces are hollow regular polygons; the distance between the upper and lower end faces is the second height H2. Optionally, the second height is typically 3mm to 10mm.

[0070] The upper end face is the light-emitting surface 3022 of the light guide module, and the upper end face and the lower end face are connected by the side of the stage body; wherein, the side of the stage body includes the inner side of the through hole near the central axis of the through hole and the outer side of the stage body away from the central axis of the through hole; the outer side of the stage body is the light-incident surface 3021 of the light guide module.

[0071] The distance between the inner side of the through hole and the central axis O of the through hole is the first half-width D1; the distance between the upper edge of the outer side of the platform and the central axis of the through hole is the second half-width D2; and the distance between the lower edge of the outer side of the platform and the central axis of the through hole is the third half-width D3; wherein, the second half-width is greater than the third half-width, that is, D2 > D3.

[0072] N light-emitting units are coaxially and symmetrically mounted in the light source mounting area of ​​the module base with the central axis of the through hole as the axis of the fifth radius R5; wherein, the fifth radius is usually smaller than the second half-width, i.e., D2 > R5. The outer side of the platform body and the lower end face form a second angle θ2, which is the same as the first angle θ1 and smaller than the half-intensity angle of the light-emitting unit.

[0073] The module base includes a light source board 303, on which a light source mounting area is provided for mounting the light source module 301. The light source mounting area is parallel to the plane containing the lower end face of the light guide module, located away from the light guide module, and the light source faces the upper end face.

[0074] Referring again to Figures 4(a) and 4(b), the light source module 301 includes N light-emitting units 3011, which are coaxially and symmetrically mounted in the light source mounting area of ​​the module base with the central axis O of the through hole as the axis. Optionally, the N light-emitting units 3011 are mounted uniformly or non-uniformly in the light source mounting area of ​​the module base. Uniformity and non-uniformity refer to whether the spacing between any two adjacent light-emitting units is consistent; if the spacing is consistent, it is considered uniform; otherwise, it is considered non-uniform.

[0075] Figure 4(a) illustrates the case where N=6, i.e., there are 6 light-emitting units 3011, showing the situation where multiple light-emitting units are evenly installed on the module base. In Figure 4(a), the light-emitting units 3011 are coaxially and symmetrically installed in the light source mounting area of ​​the module base with respect to the fifth radius R5 and the second spacing L2, with the central axis O of the through hole as the axis. The second spacing L2 is the distance between any two adjacent light-emitting units.

[0076] Figure 4(b) shows the case where N=4, i.e., there are 4 light-emitting units 3011, illustrating the situation where multiple light-emitting units are non-uniformly installed on the module base. As shown in Figure 4(b), the four light-emitting units 3011 are coaxially and symmetrically installed in the light source mounting area of ​​the module base with the central axis O of the through hole as the axis, and the spacing between any two adjacent light-emitting units is different.

[0077] In the uniform illumination modules shown in Figures 3(a), 3(b), 4(a), and 4(b), some of the light beams emitted by the light-emitting unit 301 pass through the light-incident surface 3021 of the light guide module and are emitted from the light-exit surface 3022 of the light guide module to the target object, while some of the light beams are emitted directly to the target object without passing through the light guide module.

[0078] The uniform illumination module provided in this embodiment is based on the same design concept as the uniform illumination module provided in the above embodiments. Therefore, the parameters of the uniform illumination module in Figures 3(a) and 3(b), as well as Figures 4(a) and 4(b), such as the first half-width D1, the second half-width D2, the third half-width D3, the second included angle θ2, the fifth radius R5, the second spacing L2, and the number of light-emitting units, are all designed using the same design principles as the uniform illumination module in the above embodiments. The materials used for each component in the uniform illumination module provided in this embodiment are also the same as those used for each component in the uniform illumination module provided in the above embodiments. For details, please refer to the description in the corresponding part of Embodiment 1, which will not be repeated here.

[0079] The uniform illumination module shown in this embodiment is used in biometric identification scenarios to control the uniform illumination module to project uniform infrared light to supplement the infrared receiving camera in the imaging module. Using the light source module installation method shown in Figure 4(a), the emitted light reaching the infrared receiving camera is a circular spot with uniform illumination at the center and corners, suitable for infrared receiving camera imaging chips with equal aspect ratios. Using the light source module installation method shown in Figure 4(b), the emitted light reaching the infrared receiving camera is an elliptical spot with uniform illumination at the center and corners, making the spot more suitable for infrared receiving camera imaging chips with different aspect ratios. Both light source module installation methods can avoid illumination differences caused by spacing and position variations, which helps improve the light output uniformity of the illumination module and also improves light energy utilization.

[0080] It is worth noting that the cases of 6 and 4 light-emitting units shown in Figures 4(a) and 4(b) are for illustrative purposes only and do not limit the number of light-emitting units. The number of light-emitting units is determined according to the actual situation and is not limited here.

[0081] Example 3

[0082] This embodiment proposes another structure for the uniform illumination module based on the above embodiments. This application embodiment shows a case where the light guide module is a truncated pyramid structure. Next, please refer to Figures 5(a), 5(b), and... Figure 6 Another structure of the uniform illumination module is presented.

[0083] Figures 5(a) and 5(b) are side views of another uniform illumination module provided according to an embodiment of this application. Figure 6 This is a top view of another uniform illumination module provided according to an embodiment of this application. Further, Figure 5(a) is an exploded view of the uniform illumination module, and Figure 5(b) is an assembled view of the uniform illumination module. Based on Figure 6 This allows for a direct understanding of how the light source module is installed on the module base in the uniform lighting module.

[0084] In Figure 5(a), Figure 5(b) and Figure 6 In the diagram, 501, 502, and 503 represent the light source module, the light guide module, and the light source board in the module base, respectively.

[0085] Unlike the embodiments described above, as shown in Figures 5(a), 5(b), and... Figure 6 In the uniform light illumination module shown, the light guide module 502 has a truncated quadrangular structure, and the through hole penetrating the upper and lower end faces has a truncated quadrangular structure. The upper and lower end faces are hollow rectangles. The distance between the upper and lower end faces is usually the third height H3. Optionally, the third height H3 is usually 3mm to 10mm.

[0086] The upper end face is the light-emitting surface 5022 of the light guide module, and the upper end face and the lower end face are connected by the side of the platform body; wherein, the side of the platform body includes the inner side of the through hole near the central axis of the through hole and the outer side of the platform body away from the central axis of the through hole; the outer side of the platform body is the light-incident surface 5021 of the light guide module; the distance between the inner side of the through hole and the outer side of the platform body is the first distance K1; the inner side of the through hole is parallel to the outer side of the platform body; the outer side of the platform body forms a third angle θ3 with the lower end face, and the third angle θ3 is smaller than the half-intensity angle of the light-emitting unit, just like the first angle θ1 and the second angle θ2.

[0087] The distances between the upper edge of the long side and the upper edge of the short side of the outer surface of the platform and the central axis of the through hole are the fourth half width D4 and the fifth half width D5, respectively; the distances between the lower edge of the long side and the lower edge of the short side of the inner surface of the through hole and the central axis of the through hole are the sixth half width D6 and the seventh half width D7, respectively.

[0088] The module base includes a light source board 503, on which a light source mounting area is provided for mounting the light source module 501. The light source mounting area is parallel to the plane containing the lower end face of the light guide module, located away from the light guide module, and the light source faces the upper end face.

[0089] like Figure 6 Taking a case with 12 light-emitting units (5011) as an example, this illustrates the scenario where multiple light-emitting units are evenly installed on the module base. See [link / reference]. Figure 6The light-emitting units are rectangular in shape and symmetrically mounted in the light source mounting area of ​​the module base with the central axis of the through hole as the axis. The distance between the light-emitting unit located at the diagonal of the rectangle and the central axis of the through hole is the sixth radius R6. The sixth radius R6 is generally smaller than the distance between the diagonal endpoint of the upper edge of the outer surface of the platform and the central axis of the through hole, i.e. The third spacing L3 is defined as the equal spacing between any two adjacent light-emitting units.

[0090] Figure 5(a), Figure 5(b) and Figure 6 In the provided uniform lighting module, part of the light beam emitted by the light-emitting unit 501 passes through the light-incident surface 5021 of the light guide module and is emitted from the light-exit surface 5022 of the light guide module to the target object, while part of the light beam is emitted directly to the target object without passing through the light guide module.

[0091] The uniform illumination module provided in this application embodiment is based on the same design concept as the uniform illumination module provided in the above embodiments. Therefore, Figure 5 and Figure 6 The parameters of the uniform lighting module, such as the third height H3, the first distance K1, the fourth half-width D4, the fifth half-width D5, the sixth half-width D6, the seventh half-width D7, the third included angle θ3, the third spacing L3, and the number of light-emitting units, are all designed using the same design principles as the uniform lighting module in the above embodiments. The materials used for each component in the uniform lighting module provided in this application embodiment are also the same as those used for each component in the uniform lighting module provided above; please refer to the description in the corresponding section of Embodiment 1 for details, which will not be repeated here.

[0092] The uniform illumination module shown in this application embodiment is used in a biometric identification scenario, controlling the uniform illumination module to project uniform infrared light to supplement the infrared receiving camera in the imaging module. Figure 6 The light source module installation method shown ensures that the emitted light reaching the infrared receiving camera is an elliptical spot with uniform illumination at the center and corners. This allows the light spot to be better suited for imaging chips in infrared receiving cameras with different aspect ratios. It avoids illumination differences caused by variations in spacing and position, improving the uniformity of light output from the illumination module and increasing light energy utilization.

[0093] Example 4

[0094] This embodiment further optimizes the above embodiments. The optimization scheme provided by this application embodiment is not only applicable to the case where the light guide module is a frustum structure as shown in Embodiment 1, but also applicable to the case where the light guide module is a regular frustum structure as shown in Embodiment 2, and the case where the light guide module is a quadrangular frustum structure as shown in Embodiment 3.

[0095] For ease of explanation, we will take the case of a frustum structure light guide module shown in Embodiment 1 as an example to elaborate on the optimization scheme of the uniform light illumination module.

[0096] Figure 7 This is a schematic diagram of another uniform illumination module structure provided according to an embodiment of this application. It is worth noting that... Figure 7 This is an exploded view of the uniform lighting module, which provides a more intuitive understanding of its structural components.

[0097] In an optional embodiment, the uniform illumination module also includes a reflective structure. See details below. Figure 7 , Figure 7 In the diagram, 101, 102, and 103 represent the light source module, light guide module, and light source board in the module base of the uniform light illumination module, respectively. 1021, 1022, and 1023 represent the light-incident surface, light-exit surface, and inner surface of the through hole of the light guide module, respectively.

[0098] The light guide module 102 has a first reflective structure 701 on the inner side 1023 of the through hole, and a second reflective structure 702 on the outer edge of the light source mounting area. Optionally, a groove is provided on the module base, and the first reflective structure 701 and the second reflective structure 702 are installed in the groove of the module base. The reflective surface 7011 of the first reflective structure and the reflective surface 7021 of the second reflective structure are positioned opposite each other.

[0099] Part of the light beam emitted by the light-emitting unit 101 is reflected by the reflective surfaces of the first reflective structure 701 and the second reflective structure 702 and then emitted to the target object; part of the light beam is refracted and scattered by the light-incident surface of the light guide module, and then reaches the reflective surfaces of the first reflective structure 701 and the second reflective structure 702. After being reflected multiple times by the reflective surfaces, it returns to the interior of the light guide module and is refracted and scattered again before being emitted from the light-out surface 7022 of the light guide module to the target object. A portion of the light beam is emitted directly to the target object.

[0100] The above technical solution, by adding a first reflective structure and a second reflective structure to the uniform light illumination module, and ensuring that the reflective surfaces of the first reflective structure and the second reflective structure are directly opposite each other, not only allows the light beam emitted by the light source module to form a more uniformly dispersed light beam in the light transmission area after multiple reflections from the reflective surfaces, which is beneficial to improving the light output uniformity of the uniform light illumination module, but also allows some of the ineffective light beams that originally overflowed from the outer side of the platform to return to the effective light path, which is beneficial to improving the light output illuminance of the uniform light illumination module, reducing the waste of light source energy, and improving the light energy utilization rate.

[0101] It is worth noting that the improvements to the uniform illumination module shown in the following optional embodiments can be applied to the uniform illumination module described in any of the embodiments from Embodiment 1 to Embodiment 4.

[0102] In an optional embodiment, the light-emitting surface of the light guide module is designed to combine curved and flat surfaces. Specifically, the light-emitting surface of the light guide module gradually transitions from a curved surface to a flat surface along the direction away from the central axis O of the through hole; the curved surface is used to refract light towards the central axis of the through hole. See [link to details]. Figure 8 , Figure 8 This is a schematic diagram of another uniform illumination module provided according to an embodiment of this application. It is worth noting that... Figure 8 This is a cross-sectional view of the uniform light illumination module, which allows for a more intuitive understanding of the light-emitting surface of the light guide module.

[0103] See Figure 8 , Figure 8 In the diagram, 101, 102, and 103 represent the light source module, light guide module, and light source plate in the module base of the uniform lighting module, respectively. The light-emitting surface of the light guide module in the uniform lighting module can adopt a combination of curved and flat surfaces. The light-emitting surface of the light guide module gradually transitions from curved surface 801 to flat surface 802 along the direction away from the central axis of the through-hole. The curved surface 801 is used to refract light towards the central axis O of the through-hole. This technical solution can improve the illuminance at the center of the uniform lighting module, which is beneficial for improving the uniformity of light output and the light energy utilization rate of the uniform lighting module.

[0104] In an optional embodiment, the upper surface of the light-emitting surface 1022 of the light guide module is covered with a light-diffusing sheet; and / or, the upper surface of the light-emitting surface of the light guide module is further attached with a diffusion film and / or a brightness enhancement film.

[0105] The shape of the light-diffusing sheet matches the shape of the light-emitting surface. For example, if the light-emitting surface is a circular ring structure, the light-diffusing sheet is also a circular ring structure. If the light-emitting surface is a hollow regular polygon or a hollow rectangle, the corresponding light-diffusing sheet is also a hollow regular polygon or a hollow rectangle. The light-diffusing sheet is usually made of a transparent substrate, such as PET, and optical diffusing particles are coated on both sides of the PET material. Covering the upper surface of the light-emitting surface with a light-diffusing sheet can further improve the light uniformity of the uniform illumination module.

[0106] The diffusion film is typically thin and made of materials such as PMMA, PC, or ABS (Acrylonitrile Butadiene Styrene copolymer). It is semi-transparent and can be applied with a frosted finish on the working surface and a smooth back surface. Alternatively, fluorescent particles can be added to a transparent substrate to make the light more uniform after passing through it. Anti-reflective films can concentrate more light towards the surface normal, achieving a brightening effect and increasing the uniformity and illuminance of the light guide module in a uniform lighting module.

[0107] It is worth noting that the upper surface of the light-emitting surface may be covered with a light-diffusing film and / or a brightness enhancement film in addition to a light-diffusing film. Alternatively, the upper surface of the light-emitting surface may be covered with only a light-diffusing film, or only a light-diffusing film and / or a brightness enhancement film.

[0108] In an optional embodiment, the infrared light emitting unit includes at least an infrared light source; the infrared light emitting unit also includes a lens or a light-diffusing plate; wherein the infrared light source is used to emit an infrared light beam; the light-diffusing plate and the lens are used to shape the infrared light beam.

[0109] See details Figure 9 , Figure 9 This is a schematic diagram of the structure of an infrared light-emitting unit provided according to an embodiment of this application. Wherein, Figure 9 It includes two parts: 9(a) and 9(b). Among them, Figure 9 Image 9(a) is a schematic diagram of one structure of an infrared light-emitting unit; Figure 9 Figure 9(b) shows another structural schematic diagram of the infrared light emitting unit.

[0110] like Figure 9 As shown in 9(a), the infrared light emitting unit includes an infrared light source and a lens. Figure 9 In section 9(a), 901 represents the infrared light source, and 902 represents the lens. The infrared light emitted by the infrared light source is diffused by the lens into uniform infrared light with a larger emission angle.

[0111] like Figure 9 As shown in 9(b), the infrared light emitting unit includes an infrared light source and a light homogenizer. Figure 9 As shown in 9(b), Figure 9 In section 9(b), 901 represents the infrared light source, and 903 represents the homogenizer. The infrared light emitted by the infrared light source is shaped and homogenized by the homogenizer into a rectangular uniform infrared light with a larger emission angle.

[0112] Optionally, when the infrared light emission unit includes an infrared light source and a lens, a custom lens can be used. If a custom lens is used in the infrared light emission unit, a light guide module is no longer needed in the uniform illumination module. The uniform illumination module emits uniform infrared light directly based on the custom lens, ensuring that the emitted light reaching the infrared receiving camera in the imaging module is a circular or rectangular spot with uniform illumination at the center and corners. The custom lens improves the uniformity of light output from the uniform illumination module. Using a uniform illumination module with a custom lens in biometric identification scenarios allows the emitted light reaching the infrared receiving camera to be a rectangular spot with uniform illumination at the center and corners.

[0113] In an optional embodiment, the light-emitting unit further includes a visible light-emitting unit. Specifically, see [link to relevant documentation]. Figure 10 , Figure 10 This is a top view of yet another uniform illumination module provided according to an embodiment of this application. It is worth noting that... Figure 10 This is another way to install the light source module on the module base according to the embodiments of this application.

[0114] like Figure 10 As shown, Figure 10 1001, 1002, and 1003 are the light source module, light guide module, and light source board in the module base of the uniform light illumination module, respectively.

[0115] Figure 10 Taking the example of light-emitting units being coaxially, symmetrically, and uniformly installed in the light source mounting area of ​​the module base with the central axis O of the through hole as the axis, this illustrates how to install the light-emitting units in the light source mounting area of ​​the module base when the light-emitting units include both visible light light-emitting units and infrared light-emitting units. For ease of description, N represents the number of infrared light-emitting units, and M represents the number of visible light light-emitting units. Assume N = 5 and M = 5.

[0116] Unlike the previous embodiment, this embodiment replaces the infrared supplementary lighting array in the light source module of the uniform illumination module with an infrared-and-white light supplementary lighting array. The infrared supplementary lighting array includes only infrared light emitting units; the infrared-and-white light supplementary lighting array includes both infrared light emitting units and visible light emitting units. The infrared supplementary lighting array is used to project uniform infrared light; the infrared-and-white light supplementary lighting array is used to alternately project uniform infrared light and uniform visible light.

[0117] In biometric identification scenarios, the imaging module includes not only an infrared receiving camera but also a color receiving camera. In an optional embodiment, the imaging module controls the infrared receiving camera to acquire an infrared image of the target object while simultaneously controlling the color receiving camera to acquire a visible light image of the target object. Specifically, the infrared and white light supplementary array is controlled to alternately project uniform infrared light and uniform visible light, so that the infrared receiving camera can acquire an infrared image of the target object under uniform infrared light, and the color receiving camera can acquire a visible light image of the target object under uniform visible light.

[0118] like Figure 10 As shown, the light source module 1001 includes an infrared light emitting unit 1011 and a visible light emitting unit 1012. N infrared light emitting elements 1011 and M visible light emitting units 1012 are coaxially and symmetrically alternately mounted in the light source mounting area of ​​the module base, about the central axis of the through-hole, forming a coaxial ring illumination. The light source mounting area is located on the light source plate 1003 of the module base.

[0119] The visible light emitting unit and the infrared light emitting unit emit light alternately. When the visible light emitting unit emits light, the uniform illumination module projects uniform visible light; when the infrared light emitting unit emits light, the uniform illumination module projects uniform infrared light.

[0120] Specifically, the spacing between two adjacent visible light emitting units is the fourth spacing L4. The visible light emitting units are coaxially and symmetrically mounted in the light source mounting area of ​​the module base with the central axis of the through-hole as the axis of the seventh radius R7. The fourth spacing L4 and the seventh radius R7 can be determined using the same design method as the aforementioned infrared supplementary lighting array.

[0121] Optionally, a uniform illumination module including an infrared and white light supplementary light array can be used in biometric identification scenarios. In biometric identification scenarios, the light source module installed on the module base is electrically connected to the logic control module of the controller module in the biometric identification system. The logic control module controls the infrared light emitting unit and the visible light emitting unit in the light source module to alternately emit light, so that while the infrared receiving camera in the imaging module acquires speckle infrared images or floodlight infrared images of the target object such as the face or palm, the color receiving camera in the imaging module can also acquire visible light images of the target object such as the face or palm. This can increase the types of images for biometric identification and improve the reliability of biometric identification.

[0122] In an optional embodiment, the biometric optical system further includes a proximity sensor electrically connected to a logic control module in the controller module. The proximity sensor is used to send an object proximity signal to the controller module when it senses that a target object has appeared within the system operating range of the biometric identification system.

[0123] In response to an object proximity signal, the logic control module in the controller module activates the uniform illumination module, controlling it to alternately project uniform infrared light and uniform visible light. This allows the infrared receiving camera to acquire infrared images of the target object under uniform infrared light, and the color receiving camera to acquire visible light images of the target object under uniform visible light. The combined use of the uniform illumination module and the proximity sensor further improves light energy utilization.

[0124] The collection, storage, use, processing, transmission, provision, and disclosure of user data, such as facial images and palm images, involved in the technical solutions disclosed herein comply with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0125] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this application can be achieved, and this is not limited herein.

[0126] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A uniform illumination module, characterized in that, The module includes: a light source module, a light guide module, and a module base; The light guide module has a platform structure that is wider at the top and narrower at the bottom. The light guide module has an upper end face, a lower end face, and a through hole that penetrates the upper end face and the lower end face along the axial direction of the platform. The through hole is located at the center of the platform. The upper end face and the lower end face are connected by the side of the platform body; wherein, the side of the platform body includes the inner side of the through hole near the central axis of the through hole and the outer side of the platform body away from the central axis of the through hole; the outer side of the platform body is the light-incident surface of the light guide module; the upper end face is the light-outceasing surface of the light guide module; the light guide module is mounted on the module base; The light source module includes multiple light-emitting units, which are coaxially and symmetrically mounted in the light source mounting area of ​​the module base with the central axis of the through hole as the axis; each light-emitting unit includes at least an infrared light-emitting unit. Part of the light beam emitted by the light-emitting unit passes through the light-incident surface of the light guide module and is emitted from the light-out surface of the light guide module to the target object, while part of the light beam is emitted directly to the target object without passing through the light guide module.

2. The uniform illumination module according to claim 1, characterized in that, The angle between the lower end face of the light guide module and the outer surface of the platform is the first angle, which is smaller than the half-intensity angle of the light-emitting unit; wherein, the half-intensity angle of the light-emitting unit is the angle range when the light intensity at the center of the light source of the light-emitting unit expands outward along the normal direction of the light source center and drops to half of the peak value; two adjacent light-emitting units have overlapping light fields on the light-incident surface of the light guide module.

3. The uniform illumination module according to claim 1, characterized in that, The light guide module has a first reflective structure on the inner side of the through hole and a second reflective structure on the outer edge of the light source mounting area; wherein the reflective surfaces of the first reflective structure and the second reflective structure are directly opposite each other. Part of the light beam emitted by the light-emitting unit is reflected by the reflective surfaces of the first and second reflective structures and then emitted. Part of the light beam is refracted and scattered by the incident surface of the light guide module and then reaches the reflective surfaces of the first and second reflective structures. After being reflected multiple times by the reflective surfaces, it is emitted from the light-emitting surface of the light guide module.

4. The uniform illumination module according to claim 1, characterized in that, The light-emitting surface of the light guide module gradually transitions from an arc surface to a plane along the direction away from the central axis of the through hole; the arc surface is used to refract light in the direction of the central axis of the through hole.

5. The uniform illumination module according to claim 1, characterized in that, The upper surface of the light-emitting surface of the light guide module is covered with a light-diffusing sheet; And / or, The upper surface of the light-emitting surface of the light guide module is also covered with a diffusion film and / or a brightness enhancement film.

6. The uniform illumination module according to claim 1, characterized in that, The infrared light emitting unit includes at least an infrared light source; the infrared light emitting unit further includes a lens or a light-diffusing plate; wherein, the infrared light source is used to emit an infrared light beam; the light-diffusing plate and the lens are used to shape the infrared light beam; and / or; The light-emitting unit also includes a visible light light-emitting unit, which is coaxially and symmetrically installed alternately with the infrared light-emitting unit about the central axis of the through hole in the light source mounting area of ​​the module base; the visible light light-emitting unit and the infrared light-emitting unit emit light alternately.

7. The uniform illumination module according to any one of claims 1-6, characterized in that, The platform structure is a frustum structure; the through hole penetrating the upper end face and the lower end face is a cylindrical structure, and the upper end face and the lower end face are annular structures; the distance between the upper end face and the lower end face is a first height; The distance between the inner side surface of the through hole and the central axis of the through hole is the second radius; the distance between the upper edge of the outer side surface of the platform and the central axis of the through hole is the third radius; the distance between the lower edge of the outer side surface of the platform and the central axis of the through hole is the fourth radius; wherein, the third radius is greater than the fourth radius; The light-emitting units are coaxially and symmetrically mounted in the light source mounting area of ​​the module base with the central axis of the through hole as the axis of the first radius; wherein the first radius is smaller than the third radius.

8. The uniform illumination module according to any one of claims 1-6, characterized in that, The platform structure is a regular frustum structure, the through hole penetrating the upper and lower end faces is a prism structure, the upper and lower end faces are hollow regular polygons; the distance between the upper and lower end faces is the second height; The distance between the inner side of the through hole and the central axis of the through hole is the first half-width; the distance between the upper edge of the outer side of the platform and the central axis of the through hole is the second half-width; and the distance between the lower edge of the outer side of the platform and the central axis of the through hole is the third half-width; wherein, the second half-width is greater than the third half-width. The light-emitting units are coaxially and symmetrically mounted in the light source mounting area of ​​the module base with the central axis of the through hole as the axis of the fifth radius; wherein the fifth radius is smaller than the second half width.

9. The uniform illumination module according to any one of claims 1-6, characterized in that, The platform structure is a truncated pyramid structure; the through hole penetrating the upper and lower end faces is a truncated pyramid structure; the upper and lower end faces are hollow rectangles; the distance between the upper and lower end faces is the third height; The inner side of the through hole is parallel to the outer side of the platform; the distance between the inner side of the through hole and the outer side of the platform is a first distance; The distances between the upper edge of the long side and the upper edge of the short side of the outer surface of the platform and the central axis of the through hole are the fourth half width and the fifth half width, respectively; the distances between the lower edge of the long side and the lower edge of the short side of the inner surface of the through hole and the central axis of the through hole are the sixth half width and the seventh half width, respectively. The light-emitting unit is rectangular and symmetrically mounted in the light source mounting area of ​​the module base with the central axis of the through hole as the axis; the distance between the light-emitting unit located at the diagonal of the rectangle and the central axis of the through hole is the sixth distance; Wherein, the sixth distance is less than the distance between the diagonal endpoint of the upper edge of the outer side of the platform and the central axis of the through hole; the spacing between any two adjacent light-emitting units is equal.

10. The uniform illumination module according to any one of claims 1-6, characterized in that, The uniform illumination module is electrically connected to the controller module of the biometric identification system; The controller module is also electrically connected to the imaging module in the biometric identification system; The controller module controls the activation of the uniform illumination module so that the imaging module can acquire infrared or visible light images of the target object under uniform infrared or visible light projected by the uniform illumination module. The infrared or visible light image is used to perform biometric identification on the target object.

Images