Light projector and sensing system for use with light projector

Abstract

This invention discloses a light projector and a sensing system used in conjunction with the light projector. The light projector includes a light source and a diffraction optical element. The light source has a first light-emitting area and a second light-emitting area, and the diffraction optical element is disposed on the light source. The diffraction optical element has a first diffraction structure and a second diffraction structure, which overlap the first light-emitting area and the second light-emitting area, respectively. The first diffraction structure is different from the second diffraction structure.

Description

Technical Field

[0001] The present invention relates to an electronic device, and more particularly to a light projector and a sensing system used in conjunction with the light projector. Background Technology

[0002] With technological advancements, the ability of electronic products to locate objects in their environment or with users is becoming increasingly important (e.g., augmented reality (AR), virtual reality (VR), and mixed reality (MR) tracking of user hand positions, and sensing the 3D information of objects in the environment for smart home appliances or autonomous driving). However, as the market expands the applications of electronic products, it is becoming increasingly difficult to further reduce the weight, size, and cost of existing sensing systems for use in various electronic products (such as head-mounted displays or handheld mobile devices). Solving these problems remains a challenge for relevant manufacturers. Summary of the Invention

[0003] This invention provides a light projector that can reduce costs, device size and weight, and has good versatility.

[0004] This invention provides a sensing system that reduces the number of light projectors required, further reducing costs, device size, and weight. Besides improving sensing performance, it also enhances the versatility of the sensing system and reduces its computational burden.

[0005] An embodiment of the light projector of the present invention includes a light source and a diffraction optical element. The light source has a first light-emitting area and a second light-emitting area, and the diffraction optical element is disposed on the light source. The diffraction optical element has a first diffraction structure and a second diffraction structure, which overlap the first light-emitting area and the second light-emitting area, respectively. The first diffraction structure is different from the second diffraction structure.

[0006] A sensing system according to an embodiment of the present invention includes a light source, a diffraction optical element, and a camera. The light source has a first light-emitting area and a second light-emitting area, and the diffraction optical element is disposed on the light source. The diffraction optical element has a first diffraction structure and a second diffraction structure, which overlap the first light-emitting area and the second light-emitting area, respectively, and the first diffraction structure is different from the second diffraction structure. The camera is used to receive the light beam reflected by the object under test.

[0007] Based on the above, in the light projector and sensing system of the present invention, the diffractive optical element (DOE) includes optical diffraction structures with different patterns. When a light beam emitted from the same light source passes through optical diffraction structures with different patterns, different diffraction patterns can be generated. Different diffraction patterns can be used to sense different distances. Therefore, the present invention can generate multiple diffraction patterns with a single light projector. Compared with the architecture of generating multiple diffraction patterns with multiple light projectors, it can effectively save costs and space in the device. Furthermore, the required optical diffraction structure can be tailored for different sensing distances (e.g., the object to be measured is the user's face or finger, the object to be measured is the user's surrounding environment, the object to be measured is the space where the user is located, etc.), which can greatly improve the modeling accuracy of the sensing system.

[0008] Furthermore, when light projectors or sensing systems are applied to near-eye display devices (such as augmented reality (AR), virtual reality (VR), and mixed reality (MR)) for triangulation and depth calculation, the center of the device is where the coverage of the two cameras is highest, and therefore typically covers the most optical elements. If the light projector is split into multiple units, it affects the coverage of the camera depth calculation and significantly increases the computational load required by the central processing unit (CPU) in the sensing system. Conversely, the light projector or sensing system of this invention can generate various diffraction patterns with a single light projector, thereby enabling its application in various sensing spaces and achieving optimal spatial coverage. This improves the performance of near-eye display devices, facilitates weight reduction, and significantly enhances product competitiveness.

[0009] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

[0010] The accompanying drawings are included to further illustrate the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0011] Figure 1 This is a schematic diagram of the structure of a light projector according to an embodiment of the present invention, and a schematic diagram of the diffraction pattern generated by the light projector;

[0012] Figures 2A to 2C This is a schematic diagram of a diffraction optical element and the corresponding diffraction pattern generated according to an embodiment of the present invention;

[0013] Figures 3A to 3H This is a schematic diagram of the manufacturing process of a diffractive optical element and a light-blocking layer according to an embodiment of the present invention;

[0014] Figure 4 This is a schematic diagram of the structure of a sensing system and a schematic diagram of the generated diffraction pattern according to an embodiment of the present invention.

[0015] Explanation of icon numbers

[0016] 1: Sensing system;

[0017] 10: Light projector;

[0018] 20A: First camera;

[0019] 20B: Second camera;

[0020] 100: Light source;

[0021] 101: First luminescent zone;

[0022] 102: Second luminescent area;

[0023] 103: Third luminescent zone;

[0024] 110: Diffractive optical element;

[0025] 111: First diffraction structure;

[0026] 112: Second diffraction structure;

[0027] 113: Third diffraction structure;

[0028] 120: Light blocking layer;

[0029] 130: Lens array;

[0030] 131: First lens;

[0031] 132: Second lens;

[0032] 133: Third lens;

[0033] 140: Frame;

[0034] L1 first beam;

[0035] L2: Second beam;

[0036] L3: Third beam;

[0037] DP1: First diffraction pattern;

[0038] DP2: Second diffraction pattern;

[0039] DP3: Third diffraction pattern;

[0040] G: Groove;

[0041] GS: substrate;

[0042] MS1: First microstructure;

[0043] MS2: Second microstructure;

[0044] MS3: Third microstructure;

[0045] MSA, MSB, MSC: Microstructures;

[0046] OB1: First analyte;

[0047] OB2: Second analyte;

[0048] OB3: Third analyte;

[0049] P: Graphic;

[0050] PR1: First photoresist;

[0051] PR2: Second photoresist;

[0052] PR3: Third photoresist. Detailed Implementation

[0053] As used herein, “about,” “approximately,” “essentially,” or “substantially” includes the value and the average value within an acceptable range of deviations from a particular value as determined by one of ordinary skill in the art, taking into account the measurement under discussion and a particular number of errors associated with the measurement (i.e., limitations of the measurement system). For example, “about” may mean within one or more standard deviations of the value, or, for example, within ±30%, ±20%, ±15%, ±10%, ±5%. Furthermore, the use of “about,” “approximately,” “essentially,” or “substantially” herein may be chosen to select a more acceptable range of deviations or standard deviations depending on the nature of the measurement, the cutting nature, or other properties, and may not require a single standard deviation to apply to all properties.

[0054] In the accompanying drawings, the thicknesses of layers, films, panels, regions, etc., are enlarged for clarity. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected" to another element, it may be directly on or connected to the other element, or intermediate elements may also be present. Conversely, when an element is referred to as being "directly on" or "directly connected" to another element, no intermediate elements are present. As used herein, "connection" can refer to a physical and / or electrical connection. Furthermore, an "electrical connection" may mean the presence of other elements between two elements.

[0055] Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same element references are used in the drawings and description to denote the same or similar parts.

[0056] Figure 1 This is a schematic diagram of a light projector according to an embodiment of the present invention, and an illustration of the diffraction pattern generated by the light projector. Please refer to... Figure 1 The light projector 10 includes a light source 100, a diffraction optical element 110, a light blocking layer 120, a lens array 130, and a frame 140. The light source 100 may include a first light-emitting area 101, a second light-emitting area 102, and a third light-emitting area 103. However, the invention is not limited thereto. In other embodiments, the light source 100 may include at least two light-emitting areas, such as a first light-emitting area 101 and a second light-emitting area 102. The light source 100 is used to provide a light beam; for example, the first light-emitting area 101, the second light-emitting area 102, and the third light-emitting area 103 may respectively emit a first light beam L1, a second light beam L2, and a third light beam L3 within the same wavelength range or different wavelength ranges. The wavelength range of the first light beam L1, the second light beam L2, and the third light beam L3 may include the visible light band (e.g., wavelengths between 380 nm and 750 nm) or the infrared light band (e.g., wavelengths above 750 nm or near-infrared light bands above 1054 nm), and the invention is not limited thereto.

[0057] The light source 100 can be a light-emitting diode (LED), a laser light-emitting diode (LD), or a vertical-cavity surface-emitting laser (VCSEL), etc. More specifically, the light source 100 can include at least one of a point-shaped VCSEL, a line-shaped VCSEL, an edge-emitting laser, and a random-point VCSEL; however, the invention is not limited thereto. For example, in this embodiment, the light source 100 can be a VCSEL, and the structures of the first light-emitting region 101, the second light-emitting region 102, and the third light-emitting region 103 can be fabricated by epitaxially growing different blocks of VCSELs using semiconductor processes; however, the invention is not limited thereto.

[0058] A diffractive optical element 110 is disposed on the light source 100. Specifically, the diffractive optical element 110 is disposed in the light-emitting direction of the light source 100. The diffractive optical element 110 (DOE) is an optical element obtained by fabricating microstructures on its surface using semiconductor technology, which allow light beams to diffract. When the first light beam L1, the second light beam L2, and the third light beam L3 irradiate the diffractive optical element 110, the desired diffraction pattern or structured light can be generated at a specific location or space due to the diffraction effect of the microstructure. This diffraction pattern can be a one-dimensional line, a one-dimensional dotted light spot, a two-dimensional randomly distributed light spot, or a two-dimensional regularly arranged light spot; the present invention is not limited thereto.

[0059] It is worth mentioning that, in this embodiment, the diffractive optical element 110 also has a first diffraction structure 111, a second diffraction structure 112 and a third diffraction structure 113, which overlap the first light-emitting area 101, the second light-emitting area 102 and the third light-emitting area 103 respectively, wherein the first diffraction structure 111 is different from the second diffraction structure 112.

[0060] Since the first diffraction structure 111 and the second diffraction structure 112 can have different surface microstructures, the first light beam L1 and the second light beam L2 can generate different diffraction patterns when passing through the first diffraction structure 111 and the second diffraction structure 112, respectively. For example, the first light beam L1 emitted from the first light-emitting region 101 can generate a first diffraction pattern DP1 after passing through the first diffraction structure 111, and the second light beam L2 emitted from the second light-emitting region 102 can generate a second diffraction pattern DP2 after passing through the second diffraction structure 112. Furthermore, the first diffraction pattern DP1 can include multiple high-density dot-shaped light spots, and the second diffraction pattern DP2 can include multiple stripe-shaped light spots (such as...). Figure 1 (Drawn) or multiple low-density dot-shaped light spots (not shown).

[0061] In the field of sensing, to sense the three-dimensional information of objects at different distances, structured light technology can be used. A light projector 10 emits beams of light with specific diffraction patterns to objects at different distances. A stereo depth camera then receives the diffraction pattern on the object's surface and compares it with the original projected light spot, or compares the images from two cameras (left and right). Using triangulation principles, the three-dimensional coordinates or surface contour of the object can be calculated. For example, the first diffraction pattern DP1 can be multiple high-density dot-shaped light spots with a small field of view (FOV), suitable for sensing the three-dimensional spatial information (e.g., surface contour, depth, or three-dimensional coordinates) of a first object OB1 at close range, such as the user's finger position, hand movement, or eye tracking. The second diffraction pattern DP2 can be multiple striped light spots with a wider field of view (FOV), suitable for sensing the three-dimensional spatial information (e.g., surface contour or three-dimensional coordinates) of a second object OB2 at mid-range distance, such as furniture or obstacles around the user. Therefore, a single light projector 10 can tailor the required diffraction pattern to the sensing distance of a specific object under test, significantly improving the versatility and modeling accuracy of the light projector 10 when sensing different objects and objects at different distances. Compared to implementations that use different light projectors to provide different diffraction patterns, the light projector 10 also further simplifies the device architecture and achieves device lightweighting, effectively enhancing the competitiveness of the product when applied to wearable devices.

[0062] Furthermore, the diffractive optical element 110 also includes a third diffraction structure 113 superimposed on the third light-emitting region 103, wherein the first diffraction structure 111, the second diffraction structure 112, and the third diffraction structure 113 can all be different from each other. For example, the third diffraction pattern DP3 formed after the third beam L3 passes through the third diffraction structure 113 can be different from the first diffraction pattern DP1 and the second diffraction pattern DP2. For example, the third diffraction pattern DP3 includes multiple dot-shaped light spots, and the density of the multiple dot-shaped light spots in the third diffraction pattern DP3 can be less than the density of the multiple dot-shaped light spots in the first diffraction pattern DP1. In this embodiment, the multiple dot-shaped light spots in the third diffraction pattern DP3 can be arranged in a matrix, while the dot-shaped light spots in the first diffraction pattern DP1 can be arranged in a random number arrangement, and the present invention is not limited thereto.

[0063] When the third diffraction pattern DP3 consists of multiple low-density dot-shaped light spots with a small field of view (FOV), it is suitable for low-resolution spatial sensing, reducing the computational load required for stereoscopic spatial modeling. For example, it can be used to sense the three-dimensional spatial information of a third object OB3 located at a greater distance from the user, such as the size of the room or modeling the furniture arrangement. Therefore, the light projector 10 can be applied to many different fields. It is worth noting that in embodiments not shown, the light projector may only include a first light-emitting area 101 and a second light-emitting area 102, and correspondingly, the diffraction optical element 110 may only include a first diffraction structure 111 and a second diffraction structure 112 overlapping the first light-emitting area 101 and the second light-emitting area 102, respectively. In other embodiments, the light projector may also include more light-emitting areas and correspondingly more different diffraction structures; the invention is not limited thereto.

[0064] On the other hand, a light-blocking layer 120 is disposed between the first diffraction structure 111 and the second diffraction structure 112, and between the second diffraction structure 112 and the third diffraction structure 113. The light-blocking layer 120 may include, but is not limited to, a dark-colored light-blocking material (e.g., black), a light-blocking material with high optical density (e.g., optical density OD value > 0.5), a light-blocking material with low transmittance (e.g., transmittance less than or equal to 30%) to the first beam L1, the second beam L2, and the third beam L3, or a light-blocking material with high absorptivity to the first beam L1, the second beam L2, and the third beam L3. Through the provision of the light-blocking layer 120, the proportion of the first beam L1 irradiating the adjacent second diffraction structure 112 can be reduced, the proportion of the second beam L2 irradiating the adjacent first diffraction structure 111 and the third diffraction structure 113 can be reduced, and the proportion of the third beam L3 irradiating the adjacent second diffraction structure 112 can also be reduced. In other words, the light blocking layer 120 can reduce the crosstalk between the first diffraction pattern DP1, the second diffraction pattern DP2, and the third diffraction pattern DP3 and reduce the generation of stray light. When used in the sensing field, it can further improve the clarity of structured light and the sensitivity of sensing.

[0065] Furthermore, a lens array 130 is disposed between the light source 100 and the diffraction optical element 110 to further converge the light beam emitted by the light source 100, thereby improving the light energy utilization rate of the light source 100 and the brightness of the generated diffraction pattern. More specifically, the lens array 130 includes a first lens 131, a second lens 132, and a third lens 133, all of which can be condensing lenses. In this embodiment, the first lens 131 is disposed between the first light-emitting area 101 and the first diffraction structure 111, the second lens 132 is disposed between the second light-emitting area 102 and the second diffraction structure 112, and the third lens 133 is disposed between the third light-emitting area 103 and the third diffraction structure 113. Furthermore, the refractive power of the first lens 131 can be less than that of the second lens 132, and the refractive power of the second lens 132 can be greater than that of the third lens 133.

[0066] By using lenses with different focusing capabilities in the lens array 130, the light beams emitted from the first light-emitting area 101, the second light-emitting area 102, and the third light-emitting area 103 can be focused separately, allowing the light from different areas to be focused at the desired distance. For example, the refractive power of the third lens 133 can be minimized, which can effectively improve the sharpness and clarity of the third diffraction pattern DP3 illuminating the third object under test OB3 when applied to long-distance sensing. In other embodiments, if the parallelism of the light beam emitted by the light source 100 is high, the lens array 130 can be omitted to further reduce the size, weight, and cost of the light projector; however, the invention is not limited thereto.

[0067] On the other hand, the frame 140 may have a accommodating space, allowing the light source 100, diffraction optical element 110, light blocking layer 120, and lens array 130 to be disposed within the frame 140. The frame 140 may be made of a material with high absorption rate for the first beam L1, the second beam L2, and the third beam L3, to further reduce the light leakage ratio of the beam emitted by the light source 100 and improve the light energy utilization rate. In some embodiments, the frame 140 may have an opening (not shown) to allow the circuit pins of the light source 100 to extend outside the frame 140 to provide the control signals or power signals required by the light source 100; however, the invention is not limited thereto.

[0068] Figures 2A to 2C This is a schematic diagram of a diffraction optical element and the corresponding diffraction pattern generated according to an embodiment of the present invention. Please refer to... Figure 2A The first diffraction structure 111 of the diffraction optical element 110 may include a plurality of high-density arranged first microstructures MS1, thereby generating a corresponding first diffraction pattern DP1 (e.g., a plurality of dot-shaped light spots with a random number distribution) when the first beam L1 passes through the first diffraction structure 111. Or as Figure 2BAs shown, the third diffraction structure 113 of the diffraction optical element 110 may include a plurality of low-density arranged third microstructures MS3, thereby generating a corresponding third diffraction pattern DP3 (e.g., a plurality of dot-shaped light spots arranged in a matrix) when the third beam L3 passes through the third diffraction structure 113. Similarly, as Figure 2C As shown, the second diffraction structure 112 of the diffraction optical element 110 may include a plurality of low-density arranged second microstructures MS2, thereby generating a corresponding second diffraction pattern DP2 (e.g., a plurality of regularly arranged striped light spots) when the second beam L2 passes through the second diffraction structure 112. Accordingly, different diffraction structures can be used for different sensing fields to generate different diffraction patterns, thereby improving the versatility of the light projector 10.

[0069] Figures 3A to 3H This is a schematic diagram illustrating the manufacturing process of a diffractive optical element and a light-blocking layer according to an embodiment of the present invention. Please refer to [the diagram first]. Figure 3A as well as Figure 3B The method for manufacturing the diffractive optical element 110 is, for example, by using a photolithography process. For example, a substrate GS (e.g., a glass substrate, but not limited thereto) is first provided, and a first photoresist PR1 is coated on the substrate GS. The method for coating the first photoresist PR1 is, for example, by spin coating, but the present invention is not limited thereto.

[0070] Next refer to Figures 3C to 3D First, the coated first photoresist PR1 is exposed to generate the desired pattern P on the substrate GS. Then, using a developing process and an etching process, the corresponding pattern P is fabricated into microstructures MSA, MSB, and MSC. For example, the microstructures MSA, MSB, and MSC can correspond to the first diffraction structure 111, the second diffraction structure 112, and the third diffraction structure 113 in the aforementioned embodiments, respectively; however, the invention is not limited thereto.

[0071] Next refer to Figures 3E to 3F A second photoresist PR2 is coated onto microstructures MSA, MSB, and MSC. The method for coating the second photoresist PR2 can be the same as or different from the method for coating the first photoresist PR1; the invention is not limited thereto. Next, as follows... Figure 3F As shown, the second photoresist PR2 is then subjected to a development process and an etching process to form trenches G between each pair of microstructures MSA, MSB, and MSC. At this point, the fabrication of the diffractive optical element 110 is preliminarily completed, and the first diffraction structure 111, the second diffraction structure 112, and the third diffraction structure 113 are defined.

[0072] Continue to refer to Figures 3G to 3HNext, the third photoresist PR3 can be coated into the trench G, and the third photoresist PR3 can be exposed and developed. Finally, the third photoresist PR3 is used to form the photoblocking layer 120, thereby completing the setting of the photoblocking layer 120.

[0073] Figure 4 This is a schematic diagram of the structure of a sensing system and a schematic diagram of the generated diffraction pattern according to an embodiment of the present invention. Please refer to... Figure 4 The sensing system 1 can be used to sense the three-dimensional information (e.g., depth, surface contour, or three-dimensional coordinates) of the object under test. The sensing system 1 may include the aforementioned light projector 10, a first camera 20A, and a second camera 20B. When the structured light emitted by the light projector 10 (e.g., structured light...) Figure 4 The second diffraction pattern DP2 shown in the figure is irradiated onto the object under test (e.g., Figure 4 When the second object under test (OB2) is shown, the reflected light beam can be sensed by the first camera 20A and the second camera 20B. The optical sensors (not shown) in the first camera 20A and the second camera 20B can convert the received light signal into an electrical signal. The sensing system 1 may also include a hardware processor (not shown) that can receive this electrical signal to determine the three-dimensional information of the second object under test (OB2). The hardware processor may include, for example, a microcontroller unit (MCU), a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a programmable controller, a programmable logic device (PLD), or other similar devices or combinations thereof, and the present invention is not limited thereto. In addition, in one embodiment, the functions of the hardware processor may be implemented as multiple program codes. These program codes are stored in a memory and executed by the hardware processor. Alternatively, in some embodiments, the functions of the hardware processor may be implemented as one or more circuits. The present invention does not limit the implementation of the functions of the hardware processor in software or hardware.

[0074] As mentioned earlier, the light projector 10 has multiple light-emitting areas to emit different diffraction patterns (such as...). Figure 1The first diffraction pattern DP1, the second diffraction pattern DP2, and the third diffraction pattern DP3 shown are illustrated. The hardware processor can also control the light projector 10 to generate different diffraction patterns according to different sensing distances or application scenarios, greatly improving the versatility of the sensing system 1. Furthermore, when the sensing system 1 is applied to near-eye display devices (e.g., augmented reality (AR), virtual reality (VR), and mixed reality (MR)) for triangulation and depth calculation, the center of the near-eye display device is where the coverage of the first camera 20A and the second camera 20B is highest, and therefore usually covers the most optical elements. If the light projector is split into multiple units, it will affect the coverage of the camera's depth calculation and increase the computational burden on the hardware processor. Correspondingly, the sensing system 1 of this invention can generate different diffraction patterns with a single light projector 10, thus it can be placed at the center of the near-eye display device and achieve optimal spatial coverage, improving the performance of the near-eye display device and effectively reducing product weight, size, and cost.

[0075] In summary, in the light projector and sensing system of the present invention, the diffractive optical element (DOE) includes optical diffraction structures with different patterns. When a light beam emitted from the same light source passes through optical diffraction structures with different patterns, different diffraction patterns can be generated. Different diffraction patterns can be used to sense different distances. Therefore, the present invention can generate multiple diffraction patterns with a single light projector. Compared with the architecture of generating multiple diffraction patterns with multiple light projectors, it can effectively save costs and space in the device. Furthermore, the required optical diffraction structure can be tailored for different sensing distances (e.g., the object to be measured is the user's face or finger, the object to be measured is the user's surrounding environment, the object to be measured is the space where the user is located, etc.), which can greatly improve the modeling accuracy of the sensing system.

[0076] Furthermore, when light projectors or sensing systems are applied to near-eye display devices (such as augmented reality (AR), virtual reality (VR), and mixed reality (MR)) for triangulation and depth calculation, the center of the device is where the coverage of the two cameras is highest, and therefore typically covers the most optical elements. If the light projector is split into multiple units, it affects the coverage of the camera depth calculation and significantly increases the computational load required by the central processing unit (CPU) in the sensing system. Conversely, the light projector or sensing system of this invention can generate various diffraction patterns with a single light projector, thereby enabling its application in various sensing spaces and achieving optimal spatial coverage. This improves the performance of near-eye display devices, facilitates weight reduction, and significantly enhances product competitiveness.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light projector, comprising: The light source has a first light-emitting area and a second light-emitting area; A diffractive optical element is disposed on the light source, wherein the diffractive optical element has a first diffraction structure and a second diffraction structure, which overlap the first light-emitting area and the second light-emitting area respectively, wherein the first diffraction structure is different from the second diffraction structure.

2. The light projector according to claim 1, characterized in that... It also includes a light-blocking layer disposed between the first diffraction structure and the second diffraction structure.

3. The light projector according to claim 1, characterized in that... It also includes a lens array disposed between the light source and the diffractive optical element.

4. The light projector according to claim 3, characterized in that... The lens array includes a first lens and a second lens, both of which are condenser lenses. The first lens is disposed between the first light-emitting area and the first diffraction structure, and the second lens is disposed between the second light-emitting area and the second diffraction structure. The refractive power of the first lens is greater than that of the second lens.

5. The light projector according to claim 1, characterized in that... It also includes a frame in which the light source and the diffraction optical element are disposed.

6. The light projector according to claim 1, characterized in that... The wavelength range of the light beam emitted by the light source includes at least one of the visible light band and the infrared light band.

7. The light projector according to claim 1, characterized in that... The light beam emitted by the light source forms a first diffraction pattern after passing through the first diffraction structure, and forms a second diffraction pattern after passing through the second diffraction structure. The first diffraction pattern includes multiple dot-shaped light spots, and the second diffraction pattern includes multiple stripe-shaped light spots.

8. The light projector according to claim 7, characterized in that... The light source further includes a third light-emitting region, and the diffractive optical element further includes a third diffractive structure superimposed on the third light-emitting region, wherein the first diffractive structure, the second diffractive structure, and the third diffractive structure are all different.

9. The light projector according to claim 8, characterized in that... The light beam emitted by the light source forms a third diffraction pattern after passing through the third diffraction structure. The third diffraction pattern includes multiple dot-shaped light spots, wherein the density of the multiple dot-shaped light spots in the third diffraction pattern is less than the density of the multiple dot-shaped light spots in the first diffraction pattern.

10. The light projector according to claim 1, characterized in that... The light source includes at least one of point-type vertical cavity surface-emitting laser, linear vertical cavity surface-emitting laser, edge-emitting laser, and random point vertical cavity surface-emitting laser.

11. A sensing system for sensing three-dimensional information of an object to be measured, the sensing system comprising: A light projector, the light projector comprising: A light source, having a first light-emitting area and a second light-emitting area, is used to emit the light beam to illuminate the object under test; and A diffractive optical element is disposed on the light source, wherein the diffractive optical element has a first diffraction structure and a second diffraction structure, which respectively overlap the first light-emitting region and the second light-emitting region, wherein the first diffraction structure is different from the second diffraction structure; and A camera for receiving the light beam reflected by the object under test.

12. The sensing system as claimed in claim 11, characterized in that... It also includes a light-blocking layer disposed between the first diffraction structure and the second diffraction structure.

13. The sensing system as claimed in claim 11, characterized in that... It also includes a lens array disposed between the light source and the diffractive optical element.

14. The sensing system as claimed in claim 13, characterized in that... The lens array includes a first lens and a second lens, both of which are condenser lenses. The first lens is disposed between the first light-emitting area and the first diffraction structure, and the second lens is disposed between the second light-emitting area and the second diffraction structure. The refractive power of the first lens is greater than that of the second lens.

15. The sensing system as claimed in claim 11, characterized in that... It also includes a frame in which the light source and the diffraction optical element are disposed.

16. The sensing system as claimed in claim 11, characterized in that... The wavelength range of the light beam emitted by the light source includes at least one of the visible light band and the infrared light band.

17. The sensing system as claimed in claim 11, characterized in that... The light beam forms a first diffraction pattern after passing through the first diffraction structure, and forms a second diffraction pattern after passing through the second diffraction structure. The first diffraction pattern includes multiple dot-shaped light spots, and the second diffraction pattern includes multiple stripe-shaped light spots.

18. The sensing system as claimed in claim 17, characterized in that... The light source further includes a third light-emitting region, and the diffractive optical element further includes a third diffractive structure superimposed on the third light-emitting region, wherein the first diffractive structure, the second diffractive structure, and the third diffractive structure are all different.

19. The sensing system as claimed in claim 18, characterized in that... The light beam forms a third diffraction pattern after passing through the third diffraction structure. The third diffraction pattern includes a plurality of dot-shaped light spots, wherein the density of the plurality of dot-shaped light spots in the third diffraction pattern is less than the density of the plurality of dot-shaped light spots in the first diffraction pattern.

20. The sensing system as claimed in claim 11, characterized in that... The light source includes at least one of point-type vertical cavity surface-emitting laser, linear vertical cavity surface-emitting laser, edge-emitting laser, and random point vertical cavity surface-emitting laser.

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