Polarized light module and depth recognition device

Abstract

The present application provides a polarized optical module and a depth recognition device. The polarized optical module includes: a transmitter for emitting linearly polarized light in a first wavelength range; a receiver including an image sensor, a lens structure, and a filter structure. The lens structure and the filter structure are both disposed in front of the image sensor, and light reaches the image sensor after passing through the lens structure and the filter structure. The filter structure is used to filter ambient light other than the linearly polarized light in the light, so that the image sensor receives the light filtered by the filter structure. Among them, the unfiltered light includes linearly polarized light and ambient light. This can make the light received by the image sensor less interfered by ambient light, and moreover, can improve the receiving effect of the receiver without increasing the power, thereby ensuring the imaging quality of the image and being beneficial to depth recognition. Furthermore, the filter structure can filter light in other directions in the ambient light, further reducing the influence of ambient light (i.e., noise) on the receiver.

Description

Technical Field

[0001] This application relates to the field of optical technologies, and more particularly, to a polarized light module and a depth recognition device. Background Art

[0002] With the progress of technology, depth recognition technology has been increasingly widely used, such as mobile phone unlocking, face payment, security gate, security monitoring, human-computer interaction, gesture recognition, etc. However, depth recognition technology is limited by the power of the device (due to problems such as heat dissipation and human eye protection, the transmitter power cannot be increased indefinitely). Therefore, the application distance of depth recognition technology is relatively limited, and it is usually applied to scenarios with short distances (such as mobile phone unlocking, face payment, security gate, security monitoring, etc.).

[0003] Moreover, due to the limitations of the scenario, the application of depth recognition technology will be more or less interfered by ambient light. For example, the influence of indoor fluorescent lights, outdoor sunlight, etc.: the average indoor illuminance is above 1000 Lux (Lux, the measurement unit of illuminance), and in direct sunlight in summer, the light intensity can reach 60,000 to 100,000 lx, and even outdoors without the sun, it is 1,000 to 10,000 lx.

[0004] Due to the above reasons, the existing depth recognition technology has great limitations in application distance and recognition quality. Summary of the Invention

[0005] The purpose of the embodiments of this application is to provide a polarized light module and a depth recognition device to improve the recognition quality of depth recognition technology without increasing the power of the transmitting device.

[0006] To achieve the above purpose, the embodiments of this application are implemented as follows:

[0007] In a first aspect, the embodiments of this application provide a polarized light module, including: a transmitter for emitting linearly polarized light in a first wavelength range; a receiver including an image sensor, a lens structure, and a filter structure. The lens structure and the filter structure are both disposed in front of the image sensor, and light reaches the image sensor after passing through the lens structure and the filter structure. The filter structure is used to filter ambient light other than the linearly polarized light in the light, so that the image sensor receives the light filtered by the filter structure.

[0008] In the embodiment of the present application, the transmitter emits linearly polarized light in a first wavelength range, and the receiver filters ambient light other than the linearly polarized light in the light through its filtering structure, so that the light received by the image sensor is less interfered by the ambient light. Moreover, the application of linearly polarized light can improve the effect of the light received by the receiver without increasing the power, thereby ensuring the imaging quality of the image and being beneficial to depth recognition. Under the same protection level of Class I for eye protection, compared with non-polarized light, although the power of the transmitter using linearly polarized light has not increased, the effect is better (assuming that the non-linearly polarized light is 1, 0.5 for each of the X and Y directions, the linearly polarized light has 0 in the X direction and 1 in the Y direction. At this time, under the condition of the same power, the effect of using linearly polarized light is twice that of non-linearly polarized light). Moreover, the filtering structure can filter light in other directions in the ambient light, further reducing the influence of the ambient light (i.e., noise) on the receiver.

[0009] Combined with the first aspect, in the first possible implementation manner of the first aspect, it includes: the filtering structure at least includes a first filter and a second filter. The first filter is used to transmit linearly polarized light in a second wavelength range, where the second wavelength range covers the first wavelength range; the second filter is used to transmit linearly polarized light in a third wavelength range, where the third wavelength range covers the first wavelength range, and the intersection of the second wavelength range and the third wavelength range is the first wavelength range.

[0010] In this implementation manner, the filtering structure at least includes a first filter and a second filter, and the wavelength ranges of the linearly polarized light transmitted by the first filter and the second filter both cover the linearly polarized light in the first wavelength range (the linearly polarized light emitted by the transmitter). Moreover, the wavelength ranges of the linearly polarized light transmitted by each are different, but the intersection of the wavelength ranges of all the filters is the first wavelength range. In this way, the light received by the image sensor can be filtered twice, and the ambient light that causes interference can be further blocked, and the blocked ranges are different, so that the ambient light in the light received by the image sensor can be effectively filtered, improving the effect of the light received by the receiver, and thus being beneficial to improving the recognition quality and application distance of the depth recognition technology.

[0011] Combined with the first possible implementation manner of the first aspect, in the second possible implementation manner of the first aspect, the first filter and the second filter are arranged on the first side of the lens structure, where the first side is the side of the lens structure away from the image sensor.

[0012] In this implementation, the first filter and the second filter are arranged on the first side of the lens structure (the side of the lens structure away from the image sensor). In this way, on the one hand, it is convenient for setting, and on the other hand, it can avoid the problems of optical path difference and structural interference.

[0013] Combined with the first possible implementation of the first aspect, in the third possible implementation of the first aspect, the first filter is arranged on the first side of the lens structure, and the second filter is arranged on the second side of the lens structure, where the first side is the side of the lens structure away from the image sensor, and the second side is the side of the lens structure facing the image sensor.

[0014] In this implementation, the first filter is arranged on the first side of the lens structure (the side of the lens structure away from the image sensor), and the second filter is arranged on the second side of the lens structure (the side of the lens structure facing the image sensor). In this way, when the second filter is not arranged at the flange distance, the problems of structural interference and optical path difference can also be avoided. Moreover, it is beneficial to plan the space inside the receiver.

[0015] Combined with the third possible implementation of the first aspect, in the fourth possible implementation of the first aspect, the second filter is spaced apart from the second side of the lens structure by a preset distance value.

[0016] In this implementation, the second filter is spaced apart from the second side of the lens structure by a preset distance value, and the preset value can be determined based on the flange distance of the lens, so as to ensure the filtering effect as much as possible.

[0017] Combined with the first possible implementation of the first aspect, in the fifth possible implementation of the first aspect, the lens structure includes a first lens and a second lens, and the filter structure further includes a third filter, and the third filter is used to transmit linearly polarized light in a fourth wavelength range, the fourth wavelength range covers the first wavelength range, the fourth wavelength range is different from both the third wavelength range and the second wavelength range, and the intersection of the second wavelength range, the third wavelength range and the fourth wavelength range is the first wavelength range, and the first filter, the first lens, the second filter, the second lens and the third filter are arranged in sequence, where arranged in sequence means that the filters and the lenses are alternately arranged in the setting order.

[0018] In this implementation, by setting multiple filters (the first filter, the second filter, the third filter, etc.), the ambient light can be filtered as much as possible to reduce interference. Moreover, the way of alternately arranging the filters and the lenses is beneficial to planning the space of the receiver and controlling the volume of the receiver.

[0019] Combined with the first possible implementation manner of the first aspect, in the sixth possible implementation manner of the first aspect, the first wavelength range is from x - 6 nm to x + 6 nm, the second wavelength range is from x - 20 nm to x + 6 nm, and the third wavelength range is from x - 6 nm to x + 20 nm, where the wavelength bandwidth of the emitter is from x - 6 nm to x + 6 nm.

[0020] In this implementation manner, the first wavelength range is from x - 6 nm to x + 6 nm, the second wavelength range is from x - 20 nm to x + 6 nm, and the third wavelength range is from x - 6 nm to x + 20 nm. The wavelength bandwidth of the emitter is from x - 6 nm to x + 6 nm, and the bandwidth of the laser emitter is 12 nm (of course, there are also wider and narrower bandwidths: the wider and narrower ones are too expensive and not suitable for civilian use; and the wider the laser mode, the more unfavorable it is for signal processing. In practical applications, the narrower the bandwidth of the laser emitter, the better). And x can be a laser with a common wavelength such as 940 or 850. For the second wavelength range from x - 20 nm to x + 6 nm and the third wavelength range from x - 6 nm to x + 20 nm, that is, the bandwidth of the filter can be 26 nm (which can be achieved by current technology, and the minimum bandwidth of the filter can reach 20 nm to 25 nm, and the cost is controllable). Different wavelength parts of the light can be blocked respectively, so as to achieve the purpose of double filtering, and the linearly polarized light in the required wavelength range can be transmitted, thus realizing this solution at a lower cost.

[0021] Combined with the first possible implementation manner of the first aspect, in the seventh possible implementation manner of the first aspect, the emitter is a linearly polarized laser emitter.

[0022] In this implementation manner, using a linearly polarized laser emitter to emit linearly polarized light can ensure the stability of light emission and is convenient.

[0023] In a second aspect, an embodiment of the present application provides a depth imaging device, including: a housing; a substrate disposed in the housing; a polarization light module according to any one of the first aspect or the possible implementation manners of the first aspect, where the emitter is disposed at a first position of the substrate, and the receiver is disposed at a second position of the substrate; the linearly polarized light in the first wavelength range emitted by the emitter is received by the receiver after being reflected by the target object, so as to achieve depth imaging of the target object.

[0024] In the embodiment of the present application, the polarization light module is selected as the emission module and the reception module of the depth imaging device, so as to ensure the quality of depth imaging and is also beneficial to increasing the application distance of the depth imaging device.

[0025] Combined with the second aspect, in the first possible implementation manner of the second aspect, the first position and the second position are on the same horizontal line.

[0026] To make the above objects, features, and advantages of the present application more obvious and understandable, the following provides preferred embodiments in conjunction with the accompanying drawings and describes them in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a schematic structural diagram of a depth imaging device provided by an embodiment of the present application.

[0029] Figure 2 It is a schematic diagram of the principle of the depth imaging device provided by an embodiment of the present application.

[0030] Figure 3 It is a schematic diagram of a receiver provided by an embodiment of the present application.

[0031] Figure 4 It is a schematic diagram of the light transmittance of the first filter and the second filter provided by an embodiment of the present application.

[0032] Figure 5 It is a schematic diagram of the positional relationship between the first filter structure and the lens structure provided by an embodiment of the present application.

[0033] Figure 6 It is a schematic diagram of the positional relationship between the second filter structure and the lens structure provided by an embodiment of the present application.

[0034] Figure 7 It is a schematic diagram of the positional relationship between the third filter structure and the lens structure provided by an embodiment of the present application.

[0035] Reference Signs: 100 - Depth imaging device; 110 - Housing; 120 - Substrate; 200 - Polarized light module; 210 - Transmitter; 220 - Receiver; 221 - Image sensor; 222 - Lens structure; 2221 - First lens; 2222 - Second lens; 223 - Filter structure; 2231 - First filter; 2232 - Second filter. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings in the embodiments of the present application.

[0037] Please refer to Figure 1 , Figure 1Schematic diagram of the structure of a depth imaging device 100 provided by an embodiment of the present application.

[0038] In this embodiment, the depth imaging device 100 may include: a housing 110, a substrate 120, a transmitter 210, and a receiver 220 (here, the transmitter 210 and the receiver 220 can be regarded as a polarized light module 200). The substrate 120 may be disposed inside the housing 110, and the transmitter 210 and the receiver 220 may be respectively disposed at a first position and a second position of the substrate 120.

[0039] The shape and structure of the substrate 120 may be set according to actual needs. Here, the first position and the second position of the substrate 120 are mainly introduced. The transmitter 210 is disposed at the first position of the substrate 120, and the receiver 220 is disposed at the second position of the substrate 120. Since different depth imaging devices 100 may have different position requirements for the transmitter 210 and the receiver 220. For example, in some depth imaging devices 100, the transmitter 210 and the receiver 220 are disposed on the same baseline. At this time, the first position and the second position are on the same horizontal line; while in some depth imaging devices 100, the transmitter 210 and the receiver 220 may be disposed on different baselines. At this time, the first position and the second position are on different horizontal lines.

[0040] Please refer to Figure 2 , Figure 2 Schematic diagram of the principle of the depth imaging device 100 provided by an embodiment of the present application.

[0041] In this embodiment, the transmitter 210 emits light rays. After being reflected by the target object, the light rays propagate to the position where the receiver 220 is located. The receiver 220 can receive the light rays to achieve depth imaging of the target object.

[0042] Due to the influence of ambient light and the power of the transmitter 210, the depth recognition technology still needs to be further improved in terms of application distance and imaging quality.

[0043] Based on this, the inventors of the present application propose a polarized light module 200. By the transmitter 210 emitting linearly polarized light and the receiver 220 receiving the corresponding linearly polarized light, on the one hand, the interference of ambient light can be minimized as much as possible. On the other hand, the imaging effect can be improved without increasing the power of the transmitter 210, which is beneficial to improving the recognition quality of the depth recognition technology. Hereinafter, the polarized light module 200 will be introduced in detail.

[0044] In this embodiment, the polarization optical module 200 may include a transmitter 210 and a receiver 220. Among them, the transmitter 210 is mainly used to emit linearly polarized light in a first wavelength range, while the receiver 220 is used to receive as much as possible the linearly polarized light in the first wavelength range reflected by the target object from the transmitter 210 and receive less other interfering light (such as ambient light).

[0045] Exemplarily, the transmitter 210 may be a linearly polarized laser transmitter 210 to conveniently, stably and reliably emit linearly polarized light in a first wavelength range.

[0046] Currently, fiber laser oscillators generating linearly polarized lasers can be roughly divided into two categories: one is a linearly polarized fiber laser oscillator with a spatial structure, and the other is a linearly polarized fiber laser oscillator with an all-fiber structure. However, the linearly polarized laser oscillator with a spatial structure has deficiencies such as complex structure, poor stability, and easy end face damage, while the linearly polarized laser with an all-fiber structure effectively overcomes these disadvantages. Therefore, in this embodiment, the linearly polarized laser with an all-fiber structure is taken as an example of the transmitter 210 of the polarization optical module 200 for illustration, but it should not be regarded as a limitation of this application. In some alternative ways, a linearly polarized laser with a spatial structure may also be selected as the transmitter 210, which is not limited here.

[0047] There are currently two implementation methods for the all-fiber structure linearly polarized laser oscillator: one is to orthogonally fuse two polarization-maintaining gratings, so that the reflection peaks of one pair of fast and slow axes overlap, and the reflection peaks of the other pair of fast and slow axes are misaligned, ensuring that only one polarization mode oscillates. However, for this linearly polarized laser oscillator with this implementation method, the parameters of the gratings need to be matched and the influence of temperature on the characteristics of the gratings needs to be strictly controlled. The other method is to suppress the higher-order modes and one of the polarization modes by bending the gain fiber, so that the laser oscillator realizes linearly polarized single-mode output. Of course, these two all-fiber structure linearly polarized laser oscillators have their own advantages, and the linearly polarized laser oscillator can be flexibly selected according to actual needs, which is not limited here.

[0048] In this embodiment, the transmitter 210 can emit linearly polarized light in a first wavelength range, and the first wavelength range can be from x - 6 nm (nanometers) to x + 6 nm. For example, the wavelength bandwidth of a commonly used laser is 940 ± 6 nm, 850 ± 6 nm, etc., that is, the bandwidth is 12 nm. Of course, there are also lasers with wider bandwidths (such as from x - 12 nm to x + 12 nm) and narrower bandwidths (x - 5 nm to x + 5 nm): However, lasers with wider and narrower bandwidths are too expensive and not suitable for civilian use; moreover, lasers with wider bandwidths have too many laser modes, which is not conducive to signal processing. In practical applications, the narrower the bandwidth of the laser transmitter 210, the better. Of course, this is only a consideration in terms of selection and should not be regarded as a limitation of this application. If there are solutions that use lasers with wider or narrower bandwidths, they should also be within the scope of protection of this solution.

[0049] The above is an introduction to the transmitter 210 of the polarization optical module 200. Next, the receiver 220 of the polarization optical module 200 will be introduced in detail.

[0050] Please refer to Figure 3 , Figure 3 which is a schematic diagram of a receiver 220 provided by an embodiment of the present application.

[0051] In this embodiment, the receiver 220 can include an image sensor 221, a lens structure 222, and a filter structure 223. The image sensor 221 is used to receive light for imaging. Therefore, in order to enable the image sensor 221 to receive as much of the required light as possible (such as the linearly polarized light reflected by the target after being emitted by the transmitter 210) and receive less unwanted interfering light (such as ambient light), the lens structure 222 and the filter structure 223 can both be arranged in front of the image sensor 221 to filter the light. For example, after the light passes through the lens structure 222 and the filter structure 223 and reaches the image sensor 221, the filter structure 223 is used to filter the ambient light (i.e., interfering light) other than the linearly polarized light in the light, so that the image sensor 221 receives the light filtered by the filter structure 223, where the unfiltered light includes linearly polarized light and ambient light.

[0052] Exemplarily, the lens structure 222 can be arranged in front of the image sensor 221, and the filter structure 223 can be arranged in front of the lens structure 222 (i.e., on the side away from the image sensor 221). Since existing receivers 220 usually include a lens structure 222 and an image sensor 221, therefore, arranging the filter structure 223 in front of the lens structure 222 can, in actual production, produce a suitable filter structure 223 based on the structure of the existing receiver 220 and arrange it in front of the lens, so as to transform the existing receiver 220 so that it can be applied to this solution, thereby greatly reducing costs.

[0053] Of course, the filter structure 223 can also be disposed between the lens structure 222 and the image sensor 221 to achieve light filtering, which is not limited herein.

[0054] To ensure the filtering effect, the filter structure 223 and the positional relationship between the filter structure 223 and the lens structure 222 will be introduced in detail below.

[0055] Ideally, the linearly polarized light emitted by the emitter 210 is preferably received by the receiver 220, and the light of other wavelength bands is completely blocked, so that the imaging effect of the image sensor 221 will be better. However, this is almost impossible. Limited by the existing coating equipment and technology, the minimum bandwidth that the cut-off filter can achieve currently is 20 to 25 nm. Based on this, the filter structure 223 can at least include two cooperating filter plates to filter out the interfering light through multiple filtering.

[0056] Exemplarily, the filter structure 223 can at least include a first filter plate 2231 and a second filter plate 2232. The first filter plate 2231 is used to transmit the linearly polarized light in the second wavelength range, and the second filter plate 2232 is used to transmit the linearly polarized light in the third wavelength range. Among them, the second wavelength range covers the first wavelength range, the third wavelength range covers the first wavelength range, and the intersection of the wavelength ranges of all the filter plates of the filter structure 223 is the first wavelength range (here, the intersection of the third wavelength range and the second wavelength range is the first wavelength range).

[0057] For example, the first wavelength range is from x - 6 nm to x + 6 nm. Here, the emitter 210 with a wavelength bandwidth such as 940 ± 6 nm or 850 ± 6 nm can be selected. On the one hand, these wavelength bandwidth lasers are relatively common. On the other hand, considering the application scenarios of the depth imaging device 100, there is almost visible ambient light (with a wavelength between 390 nm and 780 nm). In order to minimize the influence of the ambient light and implement this solution, it is necessary to filter out this ambient light.

[0058] In order to allow the desired light (e.g., linearly polarized light in the first wavelength range: x - 6 nm to x + 6 nm) to pass through the light filtered by the filtering structure as much as possible and filter out the unwanted interfering light (i.e., ambient light). Based on the first wavelength range (x - 6 nm to x + 6 nm) of the emitter 210, the minimum bandwidth (20 to 25 nm) that the current cut-off filter can achieve, as well as the processing difficulty and cost issues, in this embodiment, a filter with a second wavelength range of x - 20 nm to x + 6 nm (i.e., 920 nm to 946 nm, or 830 nm to 856 nm) can be selected as the first filter 2231, and a filter with a third wavelength range of x - 6 nm to x + 20 nm (i.e., 934 nm to 960 nm, or 844 nm to 870 nm) can be selected as the second filter 2232.

[0059] Through the first filter 2231 with a second wavelength range of x - 20 nm to x + 6 nm and the second filter 2232 with a third wavelength range of x - 6 nm to x + 20 nm, the wavelength range of the linearly polarized light that can pass through is x - 6 nm to x + 6 nm (i.e., the first wavelength range). In this way, the desired linearly polarized light can pass through, while the unwanted interfering light (e.g., light in the 200 nm to 830 nm range) is cut off.

[0060] Although the light transmittance of the existing single filter can reach T < 0.1%, there is still some interfering light in the transmitted light (e.g., light in the 400 nm to 700 nm range). Especially in summer, there will be 100 lx of interfering light transmission even under 100,000 lx of sunlight. Since the filtering structure 223 in this solution includes at least two filters (e.g., the first filter 2231 and the second filter 2232), and the light transmittance of each filter can be superimposed, that is, the light in the cut-off part can be further cut off. For example, the light transmittance of the first filter 2231 for the interfering light in the 400 nm to 700 nm range is T < 0.1%, and the light transmittance of the second filter 2232 for the interfering light in the 400 nm to 700 nm range can also reach T < 0.1%, thus forming a superposition and almost completely cutting off this part of the interfering light.

[0061] Please refer to Figure 4 , Figure 4 which is a schematic diagram of the light transmittance of the first filter 2231 and the second filter 2232 provided by the embodiment of the present application. Among them, Filter1 represents the first filter 2231, Filter2 represents the second filter 2232, T represents the light transmittance, and Wavelength represents the wavelength.

[0062] Therefore, the first wavelength range is from x - 6 nm to x + 6 nm, the second wavelength range is from x - 20 nm to x + 6 nm, and the third wavelength range is from x - 6 nm to x + 20 nm. The range from x - 6 nm to x + 6 nm is the wavelength bandwidth of the emitter 210. The bandwidth of the laser emitter 210 is 12 nm. x can be the laser of common wavelengths such as 940 or 850. For the second wavelength range from x - 20 nm to x + 6 nm and the third wavelength range from x - 6 nm to x + 20 nm, the light of different wavelength parts can be cut off respectively (the same cut-off parts can also be superimposed), so as to achieve the purpose of double filtering, and the linearly polarized light in the required wavelength range can be transmitted, thus realizing this solution at a lower cost.

[0063] It should be noted that in this embodiment, a filter with a bandwidth of 26 nm is taken as an example for introduction, but it is not limited thereto. Filters with other bandwidths can also be selected, such as a filter with a bandwidth of 20 nm, a filter with a bandwidth of 30 nm, etc. In addition, in this embodiment, two filters are taken as an example for illustration, but it is not limited thereto. There can also be three filters, five filters, etc., and it is not required that the bandwidths of the filters are the same, and they can be selected according to actual needs.

[0064] Please refer to Figure 5 , Figure 5 which is a schematic diagram of the positional relationship between the first filter structure 223 and the lens structure 222 provided in the embodiment of the present application.

[0065] In this embodiment, the filter structure 223 may include a first filter 2231 and a second filter 2232. The first filter 2231 and the second filter 2232 may both be disposed on the first side of the lens structure 222. Here, the first side is the side of the lens structure 222 away from the image sensor 221.

[0066] In this way, on the one hand, it is convenient for setting (and also convenient for the transformation of the existing receiver 220), and on the other hand, it can also avoid the problems of optical path difference and structural interference (the problems of optical path difference and structural interference here may occur when both filters are disposed between the lens structure 222 and the image sensor 221 and there is a filter at the back focal position of the lens structure 222 (that is, setting a filter at the back focal position of the lens structure 222 may cause problems of optical path difference and structural interference). Here, the back focal position refers to the flange distance of the lens structure 222 located between the lens structure 222 and the image sensor 221).

[0067] Please refer to Figure 6 , Figure 6 which is a schematic diagram of the positional relationship between the second filter structure 223 and the lens structure 222 provided in the embodiment of the present application.

[0068] In this embodiment, the filter structure 223 may include a first filter 2231 and a second filter 2232. The first filter 2231 is disposed on the first side of the lens structure 222, and the second filter 2232 may be disposed on the second side of the lens structure 222. Herein, the first side is the side of the lens structure 222 away from the image sensor 221, and the second side is the side of the lens structure 222 facing the image sensor 221.

[0069] By disposing the first filter 2231 on the first side of the lens structure 222 (the side of the lens structure 222 away from the image sensor 221) and the second filter 2232 on the second side of the lens structure 222 (the side of the lens structure 222 facing the image sensor 221), in this way, when the second filter 2232 is not disposed at the flange distance of the lens structure 222, the problems of structural interference and optical path difference can also be avoided. Moreover, it is beneficial to plan the space within the receiver 220.

[0070] In addition, the first filter 2231 and the second filter 2232 may also be both disposed on the second side of the lens structure 222 (the side of the lens structure 222 facing the image sensor 221). When disposed in this way, the problems of structural interference and optical path difference need to be considered, but they can also be solved through optical design. It is not impossible to dispose the first filter 2231 and the second filter 2232 on the second side of the lens structure 222 simultaneously, and no limitation is made herein.

[0071] When the first filter 2231 is disposed on the first side of the lens structure 222 and the second filter 2232 is disposed on the second side of the lens structure 222, the second filter 2232 disposed on the second side may be disposed at a preset position, that is, the second filter 2232 is spaced apart from the second side of the lens structure 222 by a preset distance value. The preset distance value may be determined based on the flange distance of the lens structure 222. For example, when the flange distance of the lens structure 222 is 25 mm (millimeters), the preset distance value may be 21 mm (certainly, it may also be other non-flange distance values, such as 15 mm, 12 mm, etc.). The second filter 2232 being spaced apart from the second side of the lens structure 222 by the preset distance value can ensure the filtering effect as much as possible.

[0072] Please refer to Figure 7 , Figure 7 which is a schematic diagram of the positional relationship between the third filter structure 223 and the lens structure 222 provided in the embodiment of the present application.

[0073] In this embodiment, the lens structure 222 includes a first lens 2221 and a second lens 2222. The filter structure 223 may include a first filter 2231, a second filter 2232, and a third filter. The third filter is configured to transmit linearly polarized light in a fourth wavelength range that covers the first wavelength range and is different from both the third wavelength range and the second wavelength range. Moreover, the intersection of the fourth wavelength range, the third wavelength range, and the second wavelength range is the first wavelength range (for example, the fourth wavelength range is from 926 nm to 946 nm, the third wavelength range is from 934 nm to 960 nm, and the second wavelength range is from 922 nm to 948 nm).

[0074] The first filter 2231, the first lens 2221, the second filter 2232, the second lens 2222, and the third filter may be arranged in sequence. Here, being arranged in sequence means that the filters and the lenses alternate with each other in the setting order. It should be noted that for this setting method, attention should be paid to avoiding setting the filter at the rear focal position of the previous lens.

[0075] By providing multiple filters (such as the first filter 2231, the second filter 2232, the third filter, etc.), environmental light can be filtered as much as possible to reduce interference. Moreover, the alternating arrangement of the filters and the lenses is conducive to planning the space of the receiver 220.

[0076] In addition, the setting method of the multiple filters is not limited to this alternating setting method. It can also be arranged in the order of the first filter 2231, the second filter 2232, the first lens 2221, the third filter, the second lens 2222, the image sensor 221, etc., which is not limited here.

[0077] It should be noted that the polarization light structure (including the transmitter 210 and the receiver 220) provided in the embodiments of the present application can be applied to the depth imaging device 100 provided in the embodiments of the present application (that is, the transmitter 210 of the polarization light module 200 emits linearly polarized light in the first wavelength range, and the receiver 220 of the polarization light module 200 can receive the light reflected by the target object to achieve depth imaging of the target object). In addition, the polarization light module 200 can also be applied to other structures, such as other types of 3D structured light modules, TOF (Time of flight), etc., which will not be elaborated here one by one.

[0078] In summary, the embodiments of the present application provide a polarized optical module and a depth imaging device. The transmitter emits linearly polarized light in a first wavelength range, and the receiver filters ambient light other than the linearly polarized light in the light through its filtering structure, so that the light received by the image sensor is less interfered by the ambient light. Moreover, the application of linearly polarized light can improve the effect of the light received by the receiver without increasing the power, thereby ensuring the imaging quality of the image and being beneficial to depth recognition. Under the same protection level of Class I for eye protection, compared with non-polarized light, although the power of the transmitter using linearly polarized light has not increased, the effect is better (assuming that non-linearly polarized light is 1, 0.5 for each of the X and Y directions, and for polarized light, the X direction is 0 and the Y direction is 1. At this time, under the condition of the same power, the effect of using linearly polarized light is twice that of non-linearly polarized light). Furthermore, the filtering structure can filter out light in other directions in the ambient light, further reducing the influence of the ambient light (i.e., noise) on the receiver.

[0079] In this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0080] The above description is only for the embodiments of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A polarization optical module, characterized in that, Comprising: A transmitter for emitting linearly polarized light in a first wavelength range; A receiver, including an image sensor, a lens structure, and a filter structure. The lens structure and the filter structure are both disposed in front of the image sensor. Light reaches the image sensor after passing through the lens structure and the filter structure. The filter structure is used to filter ambient light other than the linearly polarized light in the light, so that the image sensor receives the light filtered by the filter structure; Wherein, the filter structure at least includes a first filter and a second filter; The first filter is used to transmit linearly polarized light in a second wavelength range, wherein the second wavelength range covers the first wavelength range; The second filter is used to transmit linearly polarized light in a third wavelength range, wherein the third wavelength range covers the first wavelength range, and the intersection of the second wavelength range and the third wavelength range is the first wavelength range; The lens structure includes a first lens and a second lens. The filter structure further includes a third filter. The third filter is used to transmit linearly polarized light in a fourth wavelength range. The fourth wavelength range covers the first wavelength range. The fourth wavelength range is different from both the third wavelength range and the second wavelength range, and the intersection of the second wavelength range, the third wavelength range, and the fourth wavelength range is the first wavelength range; The first filter, the first lens, the second filter, the second lens, and the third filter are arranged in sequence. Here, arranged in sequence means that the filters and lenses are alternately arranged in the setting order, and each filter is not disposed at the rear focal position of the previous lens.

2. The polarization optical module according to claim 1, wherein The first wavelength range is from x - 6nm to x + 6nm, the second wavelength range is from x - 20nm to x + 6nm, and the third wavelength range is from x - 6nm to x + 20nm, where x - 6nm to x + 6nm is the wavelength bandwidth of the transmitter.

3. The polarization optical module according to claim 1, wherein The transmitter is a linearly polarized laser transmitter.

4. A depth imaging device, characterized in that, Comprising: A housing; A substrate disposed in the housing; The polarization light module according to any one of claims 1 to 3, wherein the transmitter is disposed at a first position of the substrate, and the receiver is disposed at a second position of the substrate; The linearly polarized light in the first wavelength range emitted by the transmitter is reflected by the target object and received by the receiver, thereby realizing depth imaging of the target object.

5. The depth imaging device according to claim 4, characterized in that, The first position and the second position are on the same horizontal line.

Images