3D imaging module

Abstract

The present application provides a three-dimensional imaging module, comprising: a projection module, comprising a light source and a diffuser; the light source is used to emit structured light with a polarization direction; the diffuser is arranged on the light-emitting side of the light source, and can be switched to a transparent state and / or a scattered state for scattering the structured light into uniform infrared light; a receiving module, comprising an infrared chip and a first polarizer; the infrared chip and the light source are spaced apart; the first polarizer is arranged on the light-incident side of the infrared chip, and the polarization direction of the first polarizer is consistent with the polarization direction of the structured light emitted by the light source. By adopting the above technical solution, the production cost of the projection module is saved, and the volume of the projection module is also reduced. In addition, the first polarizer filters out most of the ambient light to reduce the impact of the ambient light on the infrared chip, ensuring that the infrared chip can accurately identify the target object, thereby improving the imaging effect of the three-dimensional imaging module.

Description

Technical Field

[0001] The present application belongs to the field of optical imaging technology, and more specifically, relates to a three-dimensional imaging module. Background Art

[0002] The three-dimensional imaging module is mainly used to obtain three-dimensional imaging information of the imaging target, and is therefore widely used in industrial measurement and face recognition work, which has greatly improved people's living standards.

[0003] Currently, 3D imaging modules on the market generally have the following defects:

[0004] 1. A three-dimensional imaging module usually includes a structured light projector, an infrared illuminator, an infrared receiving module, and a color camera. The infrared receiving module is used to receive the structured light projected by the structured light projector to obtain an infrared image with structural features. The infrared image with structural features can be used to obtain a depth map after passing through an algorithm. The infrared receiving module is also used to receive the uniform infrared light projected by the infrared illuminator to obtain a uniform infrared image. The color camera obtains a color image. In this way, the three-dimensional imaging module can obtain an infrared image with structural features, a uniform infrared image, and a color image during operation, thereby being applied to face recognition work in the field of face recognition. However, in order to make the three-dimensional imaging module suitable for the field of face recognition, the three-dimensional imaging module needs to be equipped with two light sources: a structured light projector and an infrared illuminator. The production cost is high, and the volume of the three-dimensional imaging module is relatively large, which is not conducive to the miniaturization design of the three-dimensional imaging module.

[0005] 2. Due to the limitation of the luminous power of the structured light projector and the infrared light projector, the light intensity of the structured light emitted by the structured light projector and the uniform infrared light emitted by the infrared light projector are relatively weak. In addition, the infrared receiving module is easily interfered by the ambient light during imaging, especially when the ambient light is strong, making it difficult for the infrared receiving module to identify the target object projected by the structured light and / or uniform infrared light from the ambient light, affecting the imaging effect of the three-dimensional imaging module and thus affecting the accuracy of the depth map. Summary of the Invention

[0006] One of the purposes of the embodiments of the present application is to provide a three-dimensional imaging module, which aims to solve the technical problems in the prior art that the use of two light sources results in high cost and large size of the three-dimensional imaging module, and the infrared receiving module has difficulty in identifying target objects under strong ambient light conditions.

[0007] To solve the above technical problems, the technical solutions adopted in the embodiments of the present application are:

[0008] A three-dimensional imaging module is provided, comprising:

[0009] The projection module includes a light source and a diffuser; the light source is used to emit structured light with a polarized direction; the diffuser is arranged on the light-emitting side of the light source and can be switched to a transparent state and / or a scattered state for scattering the structured light into uniform infrared light;

[0010] The receiving module includes an infrared chip and a first polarizer; the infrared chip and the light source are spaced apart; the first polarizer is arranged on the light incident side of the infrared chip, and the polarization direction of the first polarizer is consistent with the polarization direction of the structured light emitted by the light source.

[0011] The beneficial effect of the three-dimensional imaging module provided by the embodiment of the present application is that compared with the prior art, in the present application, on the one hand, the diffuser is arranged on the light-emitting side of the light source and can be switched to a transparent state and / or a scattering state. Then, under the action of the diffuser, the structured light emitted by the light source can finally be projected onto the target object in the form of structured light and / or uniform infrared light, so that the receiving module receives the structured light and / or uniform infrared light to obtain an infrared image with structural features and / or a uniform infrared image. In this way, the projection module only needs to be equipped with one light source to realize the projection of structured light and uniform infrared light. In this way, the production cost of the projection module is saved, and the volume of the projection module is also reduced, which is conducive to the miniaturized design of the three-dimensional imaging module. On the other hand, the light source is used to emit structured light with a polarization direction, so that the structured light and / or uniform infrared light projected by the projection module are all polarized; the first polarizer is arranged on the light incident side of the infrared chip, and the polarization direction of the first polarizer is consistent with the polarization direction of the structured light emitted by the light source, that is, the polarization direction of the first polarizer is consistent with the polarization direction of the structured light and / or uniform infrared light projected by the projection module. In this way, the first polarizer filters out most of the ambient light, reducing the impact of the ambient light on the infrared chip, ensuring that the infrared chip can accurately identify the target object, thereby obtaining accurate and complete infrared images with structural features and / or uniform infrared images, thereby improving the imaging effect and accuracy of the three-dimensional imaging module.

[0012] In one embodiment, the light source includes a vertical cavity surface emitting laser and a second polarizer; the vertical cavity surface emitting laser and the infrared chip are spaced apart; the second polarizer is arranged between the vertical cavity surface emitting laser and the diffuser, and the polarization direction of the second polarizer is consistent with that of the first polarizer.

[0013] By adopting the above technical solution and setting a first polarizer and a second polarizer, the projection module can greatly reduce the interference of ambient light on the infrared chip by using only the more commonly used vertical cavity surface emitting laser, so that the infrared chip can accurately and completely identify the target object, thereby improving the imaging effect and accuracy of the three-dimensional imaging module.

[0014] In one embodiment, the light source is a horizontal cavity surface emitting laser.

[0015] By adopting the above technical solution, the interference of ambient light on the infrared chip is greatly reduced, so that the infrared chip can identify the target object more accurately and completely, while also saving the cost and volume of the projection module. In addition, it also helps to improve the diffraction uniformity and efficiency of the diffraction optical element after the subsequent design of the diffraction optical element.

[0016] In one embodiment, the diffusion sheet has a plurality of diffusion regions, and each of the diffusion regions can be switched to a transparent state or a scattering state.

[0017] By adopting the above technical solution, multiple diffusion areas are provided on the diffuser, and the diffuser is coordinated with a light source so that the infrared light projected from the diffuser at the same time contains both areas of structured light and areas of uniform infrared light. In this way, the state of the same target object under different lighting conditions can be obtained, that is, an infrared image with structural features and a uniform infrared image of the same target object can be obtained, which increases the types of infrared images collected by the algorithm and improves the security and anti-attack capability of face recognition.

[0018] In one embodiment, the plurality of diffusion regions are distributed in a matrix; or, the plurality of diffusion regions are arranged in sequence toward the periphery.

[0019] By adopting the above technical solution, the multiple diffusion areas of the diffuser can be distributed in a matrix or arranged in a circle toward the periphery according to actual needs, and the infrared image acquired by the infrared chip can have both an infrared image with structural features and a uniform infrared image. This helps to increase the flexibility of the setting of the diffuser and also ensures the accuracy of the imaging operation of the three-dimensional imaging module.

[0020] In one embodiment, the diffuser includes two conductive films and a diffuser disposed between the two conductive films, the conductive films are transparent and disposed on the light-emitting side of the light source; the conductive films are used for external voltage so that the diffuser can switch states under different voltages.

[0021] By adopting the above technical solution, the diffuser switches state under the action of voltage, thereby realizing the state switching of the entire diffuser, making the operation of switching the state of the diffuser very simple and low-cost.

[0022] In one embodiment, the diffuser is suspended particles or polymer dispersed liquid crystals.

[0023] By employing the above technical solution, both suspended particles and polymer-dispersed liquid crystals can adjust their light transmission properties under the influence of voltage, achieving state switching of the entire structure formed by the diffuser and the conductive film. Furthermore, both suspended particles and polymer-dispersed liquid crystals are relatively common and readily available, which helps simplify the manufacturing process of the diffuser.

[0024] In one embodiment, the diffusion sheet further includes two transparent substrates, and the two conductive films are disposed between the two transparent substrates.

[0025] By adopting the above technical solution, the two conductive films and the diffuser are arranged between the two transparent substrates, which helps to achieve the packaging and protection of the conductive films and the diffuser, thereby ensuring the state switching operation of the diffuser.

[0026] In one embodiment, the projection module further includes a diffraction optical element and a collimating lens, the collimating lens is arranged between the light source and the diffuser, and the diffraction optical element is arranged on the light output side of the diffuser or between the collimating lens and the diffuser; alternatively, the projection module further includes a diffraction optical element, the diffraction optical element is arranged between the light source and the diffuser, and the diffraction optical element is capable of collimating structured light.

[0027] By adopting the above-mentioned technical solution, the structured light and / or uniform infrared light projected by the projection module are collimated and diffracted before being projected onto the external target object. That is, the diffraction and collimation effects of the projection module are guaranteed, so that the structured light and / or uniform infrared light can be projected onto the external target object more accurately.

[0028] In one embodiment, the receiving module further includes an imaging lens and a filter both disposed between the infrared chip and the first polarizer; the imaging lens is disposed between the filter and the infrared chip, or the imaging lens is disposed between the filter and the first polarizer.

[0029] By adopting the above technical solution, the structured light and / or uniform infrared light reflected from the target object needs to be collimated and focused by the imaging lens, so that it can be received by the infrared chip to the maximum extent; in addition, the filter can also filter out ambient light to prevent ambient light from interfering with the infrared chip, thereby ensuring the infrared chip's recognition accuracy and imaging effect of the target object. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 A schematic diagram of a three-dimensional imaging module provided in an embodiment of the present application;

[0032] Figure 2 for Figure 1 A schematic diagram of a projection module of a three-dimensional imaging module;

[0033] Figure 3 for Figure 1 A schematic diagram of a receiving module of a three-dimensional imaging module;

[0034] Figure 4 for Figure 2 A schematic diagram of a light source of a projection module;

[0035] Figure 5 for Figure 2 A schematic diagram of a conductive film of an embodiment of a projection module;

[0036] Figure 6 for Figure 3 The imaging result of the receiving module;

[0037] Figure 7 for Figure 2 A schematic diagram of a conductive film of another embodiment of a projection module;

[0038] Figure 8 for Figure 2 Schematic diagram of the diffuser of the projection module.

[0039] Among them, the reference numerals in the figures are:

[0040] 10-mainboard; 20-projection module; 21-light source; 211-vertical cavity surface emitting laser; 212-second polarizer; 22-diffuser; 221-conductive film; 221a-conductive area; 222-diffuser; 223-electrode; 224-transparent substrate; 225-fixing glue; 23-diffraction optical element; 24-collimating lens; 30-receiving module; 31-infrared chip; 32-first polarizer; 33-imaging lens; 34-filter; 35-second circuit board; 40-color camera. DETAILED DESCRIPTION

[0041] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0042] In the description of this application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means more than two, unless otherwise specifically defined, where "more than two includes two."

[0044] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.

[0045] The following is a detailed description with reference to the accompanying drawings and embodiments:

[0046] Example 1

[0047] Please also refer to Figures 1 to 3 The 3D imaging module provided in the embodiment of the present application includes a projection module 20 and a receiving module 30 spaced apart from each other. In this embodiment, the 3D imaging module also includes a mainboard 10, on which the projection module 20 and the receiving module 30 are spaced apart. Of course, in other embodiments, the 3D imaging module may not include the mainboard 10, and both the projection module 20 and the receiving module 30 may be directly electrically connected to an external control device.

[0048] The projection module 20 includes a light source 21 and a diffuser 22. The light source 21 is mounted on and electrically connected to the mainboard 10 and is configured to emit polarized structured light. The diffuser 22 is mounted on the light-emitting side of the light source 21, and at least a portion of the diffuser 22 can be switched between a transparent state and a scattering state, allowing the diffuser 22 as a whole to switch between the transparent state and / or the scattering state. The receiving module 30 includes an infrared chip 31 and a first polarizer 32. The infrared chip 31 is mounted on and electrically connected to the mainboard 10, with the infrared chip 31 and the light source 21 spaced apart. The first polarizer 32 is mounted on the light-entering side of the infrared chip 31. As will be understood, during operation, the polarized structured light emitted by the light source 21 first passes through the diffuser 22 and is projected onto an external target object. It is then reflected from the target object and, after passing through the first polarizer 32, is received by the infrared chip 31, thereby enabling the infrared chip 31 to complete the imaging operation.

[0049] It should be noted here that the diffuser 22 can be switched to a transparent state and / or a scattering state. It is understandable that the diffuser 22 can be switched to a transparent state, or to a scattering state, or to both a transparent state and a scattering state. When the diffuser 22 is switched to a transparent state, the structured light emitted by the light source 21 is still projected onto the external target object in the form of structured light under the action of the diffuser 22 in the transparent state. The structured light is reflected on the target object and passes through the first polarizer 32 to be received by the infrared chip 31. At this time, the infrared chip 31 obtains an infrared image with structural features of the target object based on the structured light. The infrared image with structural features can obtain a depth map after calculation. When the diffuser 22 is switched to a scattering state, the structured light emitted by the light source 21 is scattered under the action of the diffuser 22 in the scattering state and is projected onto the external target object in the form of uniform infrared light. The light source 21 and the diffuser 22 in the scattering state cooperate to replace the infrared light illuminator in the prior art to achieve uniform infrared light projection. The uniform infrared light is projected onto the target object and passes through the first polarizer 32 to be received by the infrared chip 31. At this time, the infrared chip 31 obtains a uniform infrared image of the target object based on the uniform infrared light. When the diffuser 22 switches between the transparent state and the scattering state at the same time, it can be understood that a portion of the diffuser 22 is transparent and another portion is scattered. In this way, under the action of the diffuser 22, a portion of the structured light emitted by the light source 21 is still projected onto the target object in the form of structured light, while the other portion is scattered to form uniform infrared light and is also projected onto the target object in the form of uniform infrared light. Both the structured light and the uniform infrared light pass through the first polarizer 32 and are received by the infrared chip 31, thereby allowing the infrared chip 31 to simultaneously obtain an infrared image with structural features and a uniform infrared image. Therefore, in this embodiment, the action of the diffuser 22 enables the infrared chip 31 to obtain an infrared image with structural features and / or a uniform infrared image, ensuring that the three-dimensional imaging module is applied to face recognition operations.

[0050] As will be appreciated, in this embodiment, the 3D imaging module further includes a color camera 40 electrically connected to the mainboard 10. The color camera 40 is disposed on the mainboard 10 and spaced apart from the light source 21 and the infrared chip 31. The color camera 40 is used to obtain a color image of the target object.

[0051] In this embodiment, the polarization direction of the first polarizer 32 is consistent with the polarization direction of the structured light emitted by the light source 21, which is not interpreted as the polarization direction of the first polarizer 32 being exactly the same as the polarization direction of the structured light emitted by the light source 21. It can be understood that the polarization direction of the first polarizer 32 is approximately the same as or basically consistent with the polarization direction of the structured light emitted by the light source 21. It should be noted here that during imaging, the light source 21 emits structured light with a polarization direction, which is still projected onto the target object with the same polarization direction under the action of the diffuser 22. That is, the polarization direction of the structured light and / or uniform infrared light projected from the diffuser 22 to the outside is consistent with the polarization direction of the structured light emitted by the light source 21. Then, the structured light and / or uniform infrared light are reflected by the target object. Since the polarization direction of the structured light and / or uniform infrared light is consistent with the direction of the first polarizer 32, the structured light and / or uniform infrared light can pass through the first polarizer 32 and be received by the infrared chip 31. The ambient light in the external environment that is inconsistent with the polarization direction of the first polarizer 32 cannot pass through the first polarizer 32 and thus cannot be received by the infrared chip 31. In this way, the light source 21 is used to emit structured light with a polarization direction and the setting of the first polarizer 32 reduces the interference of ambient light on the infrared chip 31, thereby reducing the impact of ambient light on the imaging work of the infrared chip 31, so that the infrared chip 31 can accurately and completely identify the target object.

[0052] In the embodiment of the present application, on the one hand, the diffuser 22 is arranged on the light-emitting side of the light source 21 and can be switched to a transparent state and / or a scattering state. Then, the structured light emitted by the light source 21 can be projected onto the target object in the form of structured light and / or uniform infrared light under the action of the diffuser 22, so that the receiving module 30 receives the structured light and / or uniform infrared light to obtain an infrared image with structural features and / or a uniform infrared image. In this way, the projection module 20 is only provided with one light source 21 to realize the projection of structured light and uniform infrared light. In this way, the production cost of the projection module 20 is saved, and the volume of the projection module 20 is also reduced, which is conducive to the miniaturization design of the three-dimensional imaging module. On the other hand, the light source 21 is used to emit structured light with a polarization direction, so that the structured light and / or uniform infrared light projected by the projection module 20 are all polarized; the first polarizer 32 is arranged on the light incident side of the infrared chip 31, and the polarization direction of the first polarizer 32 is consistent with the polarization direction of the structured light emitted by the light source 21, that is, the polarization direction of the first polarizer 32 is consistent with the polarization direction of the structured light and / or uniform infrared light projected by the projection module 20. In this way, the first polarizer 32 filters out most of the ambient light to reduce the impact of the ambient light on the infrared chip 31, ensuring that the infrared chip 31 can accurately identify the target object from the ambient light, so as to obtain accurate and complete infrared images and / or uniform infrared images with structural features, thereby improving the imaging effect and accuracy of the three-dimensional imaging module.

[0053] In one embodiment, please refer to Figure 1 、 Figure 2 as well as Figure 4 The light source 21 includes a vertical cavity surface emitting laser 211 and a second polarizer 212. The vertical cavity surface emitting laser 211 is provided on the mainboard 10 and is electrically connected to the mainboard 10. It can be understood that the vertical cavity surface emitting laser 211 can be directly attached to the mainboard 10 and electrically connected to the mainboard 10. Of course, the vertical cavity surface emitting laser 211 can also be provided on a first circuit board, and the first circuit board is fixed to the mainboard 10 through a connector, so that the vertical cavity surface emitting laser 211 is electrically connected to the mainboard 10 through the first circuit board. The vertical cavity surface emitting laser 211 is used to emit structured light and is spaced apart from the infrared chip 31. The second polarizer 212 is disposed between the light-emitting side of the VCSEL 211 and the light-entering side of the diffuser 22. It is understood that the structured light emitted by the VCSEL 211 first passes through the second polarizer 212 and is polarized by the second polarizer 212 to become structured light with a fixed polarization direction. The structured light then passes through the diffuser 22 and is projected onto an external target object. It should be noted that the polarization direction of the second polarizer 212 is consistent with that of the first polarizer 32.

[0054] It should be noted that the vertical cavity surface emitting laser 211 (Vertical-Cavity Surface-Emitting Laser, VCSEL for short) is a commonly used structured light emitter, such as Figure 4 As shown, the vertical cavity surface emitting laser 211 is mainly used to emit point-shaped structured light, and the luminous power is relatively low. Outdoors or in scenes with strong ambient light, the infrared chip 31 of the receiving module 30 is easily affected by the ambient light, and it is difficult to identify the image formed by the point-shaped structured light on the target object from the ambient light. Since the polarization direction of the second polarizer 212 is consistent with the polarization direction of the first polarizer 32, the point-shaped structured light emitted by the vertical cavity surface emitting laser 211 is polarized under the polarization action of the second polarizer 212, thereby forming structured light with the same polarization direction as the first polarizer 32. In this way, the structured light that has passed through the polarization action of the second polarizer 212 can smoothly pass through the first polarizer 32 to be received by the infrared chip 31 when it passes through the diffuser 22 and the target object and is reflected through the first polarizer 32. In this way, the ambient light in the external environment that is inconsistent with the polarization direction of the first polarizer 32 cannot pass through the first polarizer 32, and thus cannot be received by the infrared chip 31. In this way, the setting of the first polarizer 32 and the second polarizer 212 reduces the interference of ambient light on the infrared chip 31, thereby reducing the influence of ambient light on the imaging work of the infrared chip 31.

[0055] It should be noted here that if Figure 4 As shown, the structured light emitted by the vertical cavity surface emitting laser 211 can be decomposed into two components with perpendicular polarization directions. The circle in the schematic diagram represents the component perpendicular to the beam propagation plane, and the short line in the schematic diagram represents the component parallel to the beam propagation plane. The arrow on the second polarizer 212 represents that the polarization direction of the second polarizer 212 is parallel to the beam propagation plane. In this way, the components of the structured light emitted by the vertical cavity surface emitting laser 211 that are parallel to the beam propagation plane can all pass through the second polarizer 212 to be projected onto the target object. Correspondingly, as Figure 3 As shown, the arrow on the first polarizer 32 indicates that the polarization direction of the first polarizer 32 is parallel to the beam propagation plane, so that the components of the structured light and / or uniform infrared light reflected from the target object that are parallel to the beam propagation plane can all pass through the first polarizer 32.

[0056] In this embodiment, by adopting the above-mentioned technical solution, a first polarizer 32 and a second polarizer 212 are set, so that the projection module 20 only uses the more commonly used vertical cavity surface emitting laser 211 to greatly reduce the interference of ambient light on the infrared chip 31, thereby enabling the infrared chip 31 to accurately and completely identify the target object from the ambient light, thereby improving the imaging effect and accuracy of the three-dimensional imaging module.

[0057] In one embodiment, please refer to Figure 2 、 Figure 5 as well as Figure 6 The diffuser 22 has multiple independent diffusion regions, each capable of switching between a transparent state and a scattering state. It is understood that the diffuser 22 has multiple electrodes 223, each of which is provided on the diffusion region. The electrodes 223 are used to connect to an external voltage. Therefore, an external device can control the voltage of each diffusion region through the corresponding electrode 223, thereby switching the diffusion region between the transparent state and the scattering state. In other words, the electrodes 223 between the multiple diffusion regions are independent of each other, and an external device can control the voltage of different diffusion regions through different electrodes 223. In this way, the multiple diffusion regions can be individually controlled to switch between the transparent state and the scattering state.

[0058] In this embodiment, among the multiple diffusion areas of the diffusion sheet 22, a part of the diffusion areas are switched to a transparent state under the voltage control of an external device, and another part of the diffusion areas are switched to a scattering state under the voltage control of an external device; the structured light emitted by the light source 21 passes through the diffusion sheet 22 and is projected to the external target object, wherein a part of the structured light passes through the diffusion area in the transparent state and is still projected from the diffusion area to the target object in the form of structured light, and the other part passes through the diffusion area in the scattering state and is scattered, thereby being projected from the diffusion area to the outside in the form of uniform infrared light. Therefore, the setting of a light source 21 changes the structure of the diffuser 22, so that the projection module 20 simultaneously projects independent structured light and uniform infrared light. In this way, the structured light and the uniform infrared light pass through the first polarizer 32 after being reflected by the target object to be received by the infrared chip 31. The infrared chip 31 obtains an infrared image based on the structured light and the uniform infrared light, and the distribution of the infrared image just corresponds to the structure of the diffuser 22. It can be understood that at this time, the infrared image obtained by the infrared chip 31 has multiple independent imaging areas, wherein a part of the imaging area is an infrared image with structural features, and another part of the imaging area is a uniform infrared image, such as Figure 6 As shown, the imaging area indicated by the reference numeral M is an infrared image with structural features, and the imaging area indicated by the reference numeral N is a uniform infrared image.

[0059] Therefore, by adopting the above-mentioned technical solution, a plurality of diffusion areas are provided on the diffusion sheet 22, so that the diffusion sheet 22 and a light source 21 cooperate to realize that an infrared image obtained by the infrared chip 31 has both an infrared image with structural features and a uniform infrared image; specifically, in actual applications, the structured light emitted by a light source 21 is projected onto the target object after the action of the diffusion sheet 22, that is, the target object is simultaneously under the illumination of structured light and uniform infrared light, and the infrared chip 31 obtains the state of the target object under the illumination of structured light and uniform infrared light at one time, so as to obtain two types of infrared images at one time. In this way, the infrared chip 31 can obtain the infrared image with structural features and the uniform infrared image at the same time without performing two receiving operations, that is, there is no need to switch the state of the diffusion sheet 22 or switch the light source 21 to realize the acquisition of the infrared image with structural features and the uniform infrared image in sequence. In this way, the infrared light projected from the diffuser 22 at the same time includes both areas of structured light and areas of uniform infrared light, so that the state of the same target object under different lighting conditions can be obtained, that is, an infrared image with structural features and a uniform infrared image of the same target object are obtained, which increases the types of infrared images collected by the algorithm and improves the security and anti-attack ability of recognition.

[0060] Of course, in this embodiment, according to actual specific needs, if only an infrared image with structural features needs to be obtained, then the external device can control the voltage of all diffusion areas of the diffuser 22 to switch all diffusion areas of the diffuser 22 to a transparent state, so that the structured light is still projected to the outside in the form of structured light after passing through all diffusion areas, and finally received by the infrared chip 31; correspondingly, if only a uniform infrared image needs to be obtained, then the external device can control the voltage of all diffusion areas of the diffuser 22 to switch all diffusion areas of the diffuser 22 to a scattering state, so that the structured light is projected to the outside in the form of uniform infrared light after passing through all diffusion areas, and finally received by the infrared chip 31.

[0061] In one embodiment, please refer to Figure 5 and Figure 6, multiple diffusion areas are distributed in a matrix. It can be understood that each diffusion area is roughly block-shaped, and multiple block-shaped diffusion areas are independent of each other and distributed in a matrix. In this way, when part of the diffusion area is switched to a transparent state and the other part of the diffusion area is switched to a scattering state, after the structured light emitted by the light source 21 passes through the diffusion plate 22, part of the structured light passes through the diffusion area in the transparent state, and the other part of the structured light passes through the diffusion area in the scattering state to form uniform infrared light. Then the structured light and the uniform infrared light are projected to the outside and received by the infrared chip 31, so that the infrared chip 31 obtains an infrared image, which has a part of an infrared image with structural features and a part of a uniform infrared image. At this time, the infrared image with structural features and the uniform infrared image are roughly block-shaped, and the infrared image with structural features and the uniform infrared image also correspond to the structure of the diffusion plate 22 and are distributed in a matrix. This helps the subsequent analysis and calculation of the infrared image with structural features and the uniform infrared image, thereby realizing the face recognition function.

[0062] See also Figure 7 In this embodiment, multiple diffusion areas can also be arranged to be arranged in sequence toward the periphery; it can be understood that the first diffusion area is located in the middle of the diffusion sheet 22, the second diffusion area is arranged in the periphery of the first diffusion area, the third diffusion area is arranged in the periphery of the second diffusion area, and at the same time are arranged in the periphery of the first diffusion area, the fourth diffusion area is arranged in the periphery of the third diffusion area... and so on, thereby realizing that multiple diffusion areas are arranged in sequence toward the periphery.

[0063] Therefore, by adopting the above-mentioned technical solution, the multiple diffusion areas of the diffusion sheet 22 can be distributed in a matrix or arranged in a circle toward the periphery in sequence according to actual needs, and the infrared image obtained by the infrared chip 31 can have both an infrared image with structural features and a uniform infrared image, and both the infrared image with structural features and the uniform infrared image can be clearly displayed. This helps to increase the flexibility of the setting of the diffusion sheet 22, and also ensures the accuracy of the imaging function of the three-dimensional imaging module.

[0064] In one embodiment, see Figure 8The diffuser 22 includes two conductive films 221 and a diffuser 222 disposed between the two conductive films 221. The conductive films 221 are transparent and disposed on the light-emitting side of the light source 21. The conductive films 221 are used to be connected to an external voltage, so that the diffuser 222 switches states under the action of different voltages, specifically including three situations in which the diffuser 222 switches to a transparent state, a scattering state, and a transparent state and a scattering state simultaneously. It is understood that the electrodes 223 are disposed on the conductive films 221, and an external device controls the voltage of the conductive films 221 through the electrodes 223, thereby switching the state of the entire diffuser 22. It is also understood that the diffuser 222 changes its structured light blocking performance under the action of voltage, thereby changing the amount of structured light that directly transmits through the conductive films 221, thereby changing the state of the entire body formed by the diffuser 222 and the conductive films 221. It should be noted here that, in this embodiment, after the external device controls the voltage of the conductive film 221, the diffuser 222 switches to a transparent state under the action of the voltage, that is, the transparent state of the entire diffuser 22 is achieved; the diffuser 222 can also switch to a scattering state, that is, the transparent state of the entire diffuser 22 is achieved; the diffuser 222 can also switch to a transparent state and a scattering state at the same time, that is, part of the diffuser 222 is in a transparent state, and part of the diffuser is in a scattering state, so that the structured light passing through the conductive film 221 is partially projected to the outside in the form of structured light, and the other part is projected to the outside in the form of uniform infrared light.

[0065] By adopting the above technical solution, the diffuser 222 switches states under the action of voltage, thereby realizing state switching of the entire diffuser 22 , making the operation of switching states of the diffuser 22 very simple and low-cost.

[0066] In this embodiment, the conductive film 221 may be formed of nano-indium tin metal oxide, carbon nanotube conductive coating, nano-silver wire, etc., and the material of the conductive film 221 is not limited here.

[0067] For specific embodiments, please refer to Figure 5 、 Figure 7 as well as Figure 8The diffuser 22 has multiple diffusion regions. It is understood that the conductive film 221 has multiple conductive regions 221a, each of which is provided with an electrode 223. A diffuser 222 is also distributed on each of the conductive regions 221a. A conductive region 221a and the diffusers 222 thereon constitute a diffusion region. It should be noted that each conductive region 221a is connected to an external voltage via the electrode 223. An external device can control the voltage of each conductive region 221a via the electrode 223 corresponding to each conductive region 221a, thereby switching the state of the diffuser 222 on the conductive region 221a. This, in turn, switches the state of the entire structure formed by the conductive film 221 and the diffuser 222. This allows a portion of the structure formed by the conductive film 221 and the diffuser 222 to be transparent, while another portion is in a scattering state. This allows the infrared chip 31 to simultaneously acquire infrared images having both structural features and uniform infrared images.

[0068] Correspondingly, the multiple conductive regions 221a of the conductive film 221 are distributed in a matrix, so that the multiple diffusion regions are distributed in a matrix; or, the multiple conductive regions 221a of the conductive film 221 are sequentially arranged toward the periphery, so that the multiple diffusion regions are sequentially arranged toward the periphery.

[0069] In one embodiment, see Figure 8 The diffuser 222 is composed of suspended particles or polymer-dispersed liquid crystals. By employing the above-described technical solution, the suspended particles can rearrange themselves under the action of a voltage to adjust their structured light transmission performance. Alternatively, the polymer-dispersed liquid crystals can adjust the refractive index of the polymer-dispersed liquid crystal droplets under the action of a voltage. This allows the light transmission performance of the diffuser 222 to be adjusted, switching the state of the suspended particles or polymer-dispersed liquid crystals, thereby adjusting the structured light transmission performance of the entire structure formed by the diffuser 222 and the conductive film 221. Furthermore, suspended particles or polymer-dispersed liquid crystals are both common and readily available, simplifying the manufacturing process of the diffuser 22.

[0070] In one embodiment, see Figure 8The diffuser 22 further includes two transparent substrates 224, which are glass substrates. The two conductive films 221 are disposed between the two transparent substrates 224, and the diffuser 222 is disposed between the two conductive films 221. By adopting the above technical solution, the diffuser 222 is disposed between the two conductive films 221. In this way, the diffuser 222 is sandwiched between the two conductive films 221, thereby encapsulating and protecting the diffuser 222, helping to prevent leakage of the diffuser 222, thereby ensuring the state switching operation of the diffuser 222. In addition, the transparent substrates 224 are transparent, which facilitates the transmission of structured light and / or uniform infrared light. The two conductive films 221 and the diffuser 222 are both disposed between the two transparent substrates 224, which helps to encapsulate and protect the conductive films 221 and the diffuser 222, thereby ensuring the state switching operation of the diffuser 22.

[0071] It should be noted that the structured light emitted by the light source 21 first passes through a transparent substrate 224 and a conductive film 221 in sequence, and then forms structured light and / or uniform infrared light after passing through the diffuser 222. Finally, it passes through another conductive film 221 and another transparent substrate 224 in sequence to be projected onto an external target object. Of course, in this embodiment, the transparent substrates 224 can also be provided as three, four, or more than five, and the specific distribution can be set according to actual needs.

[0072] In a specific embodiment, a fixing glue 225 is provided between the transparent substrate 224 and the conductive film 221 , and the fixing glue 225 is used to fix the transparent substrate 224 and the conductive film 221 .

[0073] In one embodiment, see Figure 2 The projection module 20 also includes a diffractive optical element 23 and a collimating lens 24. The collimating lens 24 is arranged between the light exit side of the light source 21 and the light entrance side of the diffuser 22. It can be understood that when the light source 21 includes a vertical cavity surface emitting laser 211 and a second polarizer 212, the collimating lens 24 is arranged between the light exit side of the second polarizer 212 and the light entrance side of the diffuser 22. The diffractive optical element 23 is arranged between the light exit side of the collimating lens 24 and the light entrance side of the diffuser 22. It can be understood that the light source 21, the collimating lens 24, the diffractive optical element 23 and the diffuser 22 are distributed in sequence along the light exit side of the light source 21. The structured light emitted by the light source 21 first undergoes the collimation effect of the collimating lens 24, then undergoes the diffraction effect of the diffractive optical element 23, and finally is projected to the outside through the diffusion effect of the diffuser 22. Of course, in other embodiments, the diffractive optical element 23 can also be arranged to be located on the light exit side of the diffuser 22.

[0074] In another embodiment, the projection module 20 further includes a diffraction optical element 23 for diffracting structured light. The diffraction optical element 23 is disposed between the light-emitting side of the light source 21 and the light-entering side of the diffuser 22. It can be understood that when the light source 21 includes a vertical cavity surface emitting laser 211 and a second polarizer 212, the diffraction optical element 23 is disposed between the light-emitting side of the second polarizer 212 and the light-entering side of the diffuser 22. Moreover, in this embodiment, the diffraction optical element 23 can also collimate the structured light. In this embodiment, the diffraction optical element 23 integrates the two functions of diffraction and collimation, so that the structured light emitted from the light source 21 can achieve diffraction and collimation after passing through the diffraction optical element 23. In this way, the use of optical elements is reduced, thereby reducing the design cost and volume of the projection module 20.

[0075] By adopting the above-mentioned technical solution, the structured light and / or uniform infrared light projected by the projection module 20 are collimated and diffracted before being projected onto the external target object. That is, the diffraction and collimation effects of the projection module 20 are guaranteed, so that the structured light and / or uniform infrared light can be projected onto the external target object more accurately.

[0076] In one embodiment, see Figure 3The receiving module 30 further includes an imaging lens 33 and a filter 34, both of which are disposed between the infrared chip 31 and the first polarizer 32. The imaging lens 33 is disposed between the light-entering side of the filter 34 and the light-exiting side of the first polarizer 32. It will be appreciated that the structured light and / or uniform infrared light reflected by the target object is first polarized by the first polarizer 32, then focused by the imaging lens 33, and finally filtered by the filter 34 before being received by the infrared chip 31. It should be noted here that the structured light and / or uniform infrared light reflected by the target object, after being reflected by the target object, is incident on the first polarizer 32 at the same time as the ambient light. The first polarizer 32 will filter out the light perpendicular to its polarization direction, that is, most of the ambient light is filtered out. In this way, the structured light and / or uniform infrared light and a small part of the ambient light are focused by the imaging lens 33, and then filtered by the filter 34, and finally the structured light and / or uniform infrared light are received by the infrared chip 31, that is, the filter 34 filters out the ambient light. In this way, the interference of ambient light on the infrared chip 31 is avoided, and the recognition accuracy and imaging effect of the infrared chip 31 for the target object are guaranteed. By adopting the above-mentioned technical solution, the structured light and / or uniform infrared light reflected from the target object must be focused by the imaging lens 33, so that they can be received by the infrared chip 31 to the maximum extent. In addition, the filter 34 can also filter out ambient light, preventing ambient light from interfering with the infrared chip 31. In this way, the infrared chip 31 ensures the accuracy of target object recognition and imaging effect. In addition, it should be noted that the first polarizer 32 can filter out ambient light with a polarization direction different from that of the first polarizer 32, and the filter 34 can also filter out other ambient light. Moreover, the first polarizer 32 and the filter 34 can allow all structured light and / or uniform infrared light to pass through, thereby greatly avoiding interference of ambient light on the infrared chip 31.

[0077] Of course, in other embodiments, the imaging lens 33 may also be arranged between the light-emitting side of the filter 34 and the light-incident side of the infrared chip 31.

[0078] In a specific embodiment, the receiving module 30 also includes a second circuit board 35, the infrared chip 31 is arranged on the second circuit board 35, and the second circuit board 35 is arranged on the main board 10 and electrically connected to the main board 10, then the infrared chip 31 forms an electrical connection with the main board 10 through the second circuit board 35; of course, in other embodiments, the infrared chip 31 can also be directly attached to the main board 10 and electrically connected to the main board 10.

[0079] Example 2

[0080] This embodiment is substantially the same as the first embodiment, with the only difference being that the light source 21 is a horizontal cavity surface emitting laser. The HCSEL is fixed to the mainboard 10 via a first circuit board and electrically connected to the mainboard 10; alternatively, the HCSEL is directly attached to the mainboard 10 and electrically connected to the mainboard 10. It should be noted that using a horizontal cavity surface emitting laser (HCSEL) as the light source 21 has the following advantages: First, the HCSEL is primarily used to emit linear structured light. The structured light emitted by the HCSEL has a polarization direction, and the polarization direction of the structured light emitted by the HCSEL is consistent with the polarization direction of the first polarizer 32. This allows the structured light emitted by the HCSEL to pass through the first polarizer 32 after the action of the diffuser 22 and be received by the infrared chip 31. The HCSEL and the first polarizer 32 work together to filter out most of the ambient light, thereby greatly reducing the interference of ambient light on the infrared chip 31, allowing the infrared chip 31 to more accurately and completely identify the target object. Second, the horizontal cavity surface emitting laser has a high luminous power, and the entire surface of the horizontal cavity surface emitting laser as the light source 21 can emit light, and the luminous density is relatively large, so that the infrared chip 31 can better identify the target object. Third, the polarization of the structured light emitted by the horizontal cavity surface emitting laser is relatively good, which helps to make the diffraction uniformity and diffraction efficiency of the diffraction optical element 23 higher when matching the polarization characteristics of the horizontal cavity surface emitting laser to design the diffraction optical element 23. Fourth, the divergence angle of the horizontal cavity surface emitting laser is relatively small, that is, the structured light emitted from the horizontal cavity surface emitting laser has a certain collimation effect, thereby reducing the design difficulty of the collimator. In this way, the collimation function of the collimator can be directly integrated into the diffraction optical element 23, so that the diffraction optical element 23 has a collimation function, thereby further saving the design cost of the projection module 20 and reducing the volume of the projection module 20, which is conducive to the miniaturization design of the three-dimensional imaging module.

[0081] The rest of this embodiment is the same as that of the first embodiment. The features not explained in this embodiment are all based on the explanations of the first embodiment and will not be described in detail here.

[0082] Example 3

[0083] The contents of this embodiment are substantially the same as those of the first embodiment, with the only difference being that the diffuser 22 can also be configured to have only one diffusion region, and correspondingly, the conductive film 221 also has only one conductive region 221a. Thus, an external device controls the voltage of the conductive film 221 so that the diffuser 222 on the conductive film 221 moves on the conductive film 221, thereby switching the diffuser 222 to a transparent state or a scattering state.

[0084] The rest of this embodiment is the same as that of the first embodiment. The features not explained in this embodiment are all based on the explanations of the first embodiment and will not be described in detail here.

[0085] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A three-dimensional imaging module, characterized in that: include: The projection module includes a light source and a diffuser; the light source is used to emit structured light with a polarization direction; The diffuser is provided on the light-emitting side of the light source and can be switched to a transparent state and / or a scattering state for scattering the structured light into uniform infrared light; A receiving module, comprising an infrared chip and a first polarizer; the infrared chip and the light source are spaced apart; the first polarizer is disposed on the light incident side of the infrared chip, and the polarization direction of the first polarizer is consistent with the polarization direction of the structured light emitted by the light source; The diffusion sheet has multiple diffusion areas, each of which can be switched to a transparent state or a scattering state; each diffusion area is provided with an electrode, which is used to connect an external voltage; the projection module can simultaneously project independent structured light and uniform infrared light, so that the infrared image obtained by the infrared chip has multiple independent imaging areas, wherein a part of the imaging areas are infrared images with structural features, and another part of the imaging areas are uniform infrared images.

2. The three-dimensional imaging module according to claim 1, wherein: The light source includes a vertical cavity surface emitting laser and a second polarizer; the vertical cavity surface emitting laser and the infrared chip are spaced apart; the second polarizer is arranged between the vertical cavity surface emitting laser and the diffuser, and the polarization direction of the second polarizer is consistent with that of the first polarizer.

3. The three-dimensional imaging module according to claim 1, wherein: The light source is a horizontal cavity surface emitting laser.

4. The three-dimensional imaging module according to claim 1, wherein: The plurality of diffusion regions are distributed in a matrix; or, the plurality of diffusion regions are arranged in a circle toward the periphery.

5. The three-dimensional imaging module according to any one of claims 1 to 4, wherein: The diffuser includes two conductive films and a diffuser disposed between the two conductive films. The conductive films are transparent and disposed on the light-emitting side of the light source. The conductive films are used for externally connecting voltages so that the diffuser switches states under different voltages.

6. The three-dimensional imaging module according to claim 5, wherein: The diffuser is suspended particles or polymer dispersed liquid crystal.

7. The three-dimensional imaging module according to claim 5, wherein: The diffusion sheet further includes two transparent substrates, and the two conductive films are both arranged between the two transparent substrates.

8. The three-dimensional imaging module according to any one of claims 1 to 4, wherein: The projection module also includes a diffraction optical element and a collimating lens, the collimating lens is arranged between the light source and the diffuser, and the diffraction optical element is arranged on the light output side of the diffuser or between the collimating lens and the diffuser; alternatively, the projection module also includes a diffraction optical element, the diffraction optical element is arranged between the light source and the diffuser, and the diffraction optical element is capable of collimating structured light.

9. The three-dimensional imaging module according to any one of claims 1 to 4, wherein: The receiving module also includes an imaging lens and a filter, both of which are arranged between the infrared chip and the first polarizer; the imaging lens is arranged between the filter and the infrared chip, or the imaging lens is arranged between the filter and the first polarizer.

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