Laser projection module

Abstract

The laser projection module comprises a light source, a base and an optical element, the light source is located in an inner cavity of the base, the optical element covers an opening of the inner cavity, the optical element is provided with a first area and a second area, and the first area surrounds and wraps the second area; the optical element comprises a light absorption structure arranged in the first area and a light splitting structure arranged in the second area, the light absorption structure is used for absorbing light emitted by the light source to the first area, and the light splitting structure is used for shaping light emitted by the light source to the second area; the light absorption structure comprises a plurality of protruding nano-structure parts, and the plurality of nano-structure parts are used for being arranged at intervals according to a specific distribution proportion, so that the transmittance of light emitted to the first area is lower than the transmittance threshold value of the optical element. According to the embodiment of the invention, the optical element is arranged in the laser projection module, and the optical element comprises the light absorption structure with the plurality of nano-structure parts, so that the contrast ratio and the energy utilization rate of light spots projected by the laser projection module are improved.

Description

Technical Field

[0001] The invention belongs to the field of optics, and in particular relates to a laser projection module. Background Art

[0002] Nowadays, with the development of optical technology, the application scope of the technology of obtaining structured light through laser projection modules is getting wider and wider. Structured light is a projection formed by projecting a specific pattern onto the surface of an object, and is collected by a receiving module. The position and depth information of the object are calculated according to the changes in the light signal caused by the object, and then the entire depth space is restored. Therefore, the quality of structured light is related to the accuracy of the final result of the instrument. However, the light spot projected by the existing laser projection module has the problems of low contrast and low energy efficiency. Summary of the invention

[0003] An embodiment of the present application provides a laser projection module. An optical element is arranged in the laser projection module. The optical element includes a light-absorbing structure having a plurality of nanostructures, thereby improving the contrast and energy utilization rate of a light spot projected by the laser projection module.

[0004] In the first aspect, an embodiment of the present application provides a laser projection module, including a light source, a base and an optical element, the light source is located in an inner cavity of the base, the optical element covers an opening of the inner cavity, the optical element has a first area and a second area, the first area surrounds and wraps the second area; the optical element includes a light absorbing structure arranged in the first area and a spectroscopic structure arranged in the second area, the light absorbing structure is used to absorb the light emitted from the light source to the first area, and the spectroscopic structure is used to shape the light emitted from the light source to the second area; the light absorbing structure includes a plurality of protruding nanostructure portions, and the plurality of nanostructure portions are used to be spaced and arranged to have a specific distribution ratio so that the transmittance of the light emitted to the first area is lower than the transmittance threshold of the optical element.

[0005] The embodiment of the present application is to set an optical element including a light absorbing structure and a light splitting structure in the laser projection module, wherein the light absorbing structure is located in the first area of ​​the light incident surface of the optical element, and the light splitting structure is located in the second area of ​​the light incident surface of the optical element. The light absorbing structure has a plurality of nanostructure parts distributed at intervals, so that the light emitted by the light source to the first area can be reflected and scattered multiple times on the surface or inside of the nanostructure part, that is, at least part of the light emitted by the light source to the first area can be captured and absorbed by the light absorbing structure, and then the light emitted by the light source to the second area can form a uniform light spot under the shaping of the light splitting structure, avoiding crosstalk and interference of the light emitted to the first area with the light emitted to the second area, and finally improving the contrast and energy utilization of the light spot projected by the laser projection module.

[0006] In one possible embodiment, the ratio of the diameter of the current nanostructure portion to the spacing between the centers of the current nanostructure portion and the adjacent nanostructure portion is 0.54-0.61, or 0.69-0.80, so that the transmittance of the multiple nanostructure portions to light is close to 0, which is beneficial to further avoid crosstalk and interference of the light emitted to the first area with the light emitted to the second area.

[0007] In one possible embodiment, the diameters of multiple nanostructure parts are the same, and the ratio of the diameter of a nanostructure part to the distance between the centers of any two adjacent nanostructure parts is 0.54-0.61, or 0.69-0.80. A simpler mold can be used to prepare multiple nanostructure parts of consistent size, thereby improving the contrast and energy utilization of the light spot projected by the laser projection module while reducing the processing difficulty of the optical element.

[0008] In one possible embodiment, the nanostructure portion includes a first protrusion and a second protrusion that are spaced apart, and the ratio of the diameter of the first protrusion to the distance between the centers of any two adjacent first protrusions and the second protrusion is 0.54-0.61, or 0.69-0.80; the ratio of the diameter of the second protrusion to the distance between the centers of any two adjacent first protrusions and the second protrusion is 0.54-0.61, or 0.69-0.80, so that the transmittance of the multiple first protrusions and the second protrusions to light is close to 0, which is beneficial to further avoid crosstalk and interference of light emitted to the first area with light emitted to the second area.

[0009] In one possible embodiment, the nanostructure portion is a first nanostructure portion, the spectroscopic structure includes a plurality of second nanostructure portions that are spaced and protrude toward the light source, and the first nanostructure portion and the second nanostructure portion are integrally formed. For example, the first nanostructure portion and the second nanostructure portion can be obtained simultaneously by sequentially performing a photolithography process and an etching process on the light absorption structure and the spectroscopic structure on the incident surface, that is, by a set of process flows. By obtaining the integrally formed first nanostructure portion and second nanostructure portion through one-time processing, the optical element can have high precision and high reliability, which is beneficial to improving the light absorption effect and spectroscopic effect of the optical element, and ultimately improving the contrast and energy utilization of the light spot projected by the laser projection module. In another possible embodiment, the first nanostructure portion and the second nanostructure portion can be directly obtained on the first area and the second area of ​​the optical element at one time by performing related processes such as a photolithography process and an etching process on the incident surface.

[0010] In one possible implementation, the ratio of the diameter of the current second nanostructure portion to the spacing between the centers of the current second nanostructure portion and the second nanostructure portion adjacent to it is 0.3-0.53, or 0.62-0.68, or 0.81-0.85, so that the transmittance of multiple second nanostructure portions to light can be maintained above 90%, which is beneficial to improving the utilization rate of the light emitted to the second area by the spectroscopic structure, and ultimately improving the contrast and energy utilization rate of the light spot projected by the laser projection module.

[0011] In a possible embodiment, the second nanostructure portion includes a third protrusion and a fourth protrusion that are spaced apart, and the ratio of the diameter of the third protrusion to the distance between the centers of any two adjacent third protrusions and the fourth protrusion is 0.3-0.53, or 0.62-0.68, or 0.81-0.85; the ratio of the diameter of the fourth protrusion to the distance between the centers of any two adjacent third protrusions and the fourth protrusion is 0.3-0.53, or 0.62-0.68, or 0.81-0.85, so that the transmittance of the plurality of third protrusions and the fourth protrusion to light can be maintained at more than 90%, which is beneficial to improving the utilization rate of the light emitted to the second area by the light splitting structure, and ultimately improving the contrast and energy utilization rate of the light spot projected by the laser projection module.

[0012] In one possible implementation, the center of the second area is directly opposite to the light source, so that the spectroscopic structure can fully shape the light entering the second area, and the light-absorbing structure can fully absorb the light entering areas outside the second area, thereby avoiding crosstalk and interference of other light on the light emitted to the second area, thereby ultimately improving the contrast and energy utilization of the light spot projected by the laser projection module.

[0013] In one possible implementation, the angle formed by the direction between the edge of the second area and the light source and the direction of the light source is 18-24°, so that the nanostructure portion of the light-absorbing structure can fully absorb the light incident into the first area, and the spectroscopic structure can fully shape the light incident into the second area, which is beneficial to improving the contrast and energy utilization of the light spot projected by the laser projection module.

[0014] In one possible embodiment, the optical element has an isolation portion with a smooth surface, and at least part of the isolation portion is located between the first area and the base to prevent capillary overflow from damaging the function of the optical element, which is beneficial to improving the contrast and energy utilization of the light spot projected by the laser projection module. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of the structure of a laser projection module provided in an embodiment of the present application;

[0016] Figure 2is a schematic diagram of the structure of an optical element provided in an embodiment of the present application;

[0017] Figure 3 is a transmittance curve diagram of multiple nanostructures provided in an embodiment of the present application;

[0018] Figure 4 is a schematic structural diagram of an optical element provided by another embodiment of the present application;

[0019] Figure 5 yes Figure 4 A physical picture of the optical components shown in ;

[0020] Figure 6 is a schematic structural diagram of an optical element provided by another embodiment of the present application;

[0021] Figure 7 is a schematic structural diagram of an optical element provided by another embodiment of the present application;

[0022] Figure 8 is a schematic structural diagram of an optical element provided by another embodiment of the present application;

[0023] Fig. 9 It is a schematic diagram of an application scenario of a laser projection module provided in an embodiment of the present application;

[0024] Fig.10 It is a comparison chart of the projection effects of a traditional laser projection module and a laser projection module provided in an embodiment of the present application.

[0025] Reference numerals:

[0026] 1-laser projection module; 2-light source; 3-base; 31-inner cavity; 311-opening; 4-optical element; 41-light incident surface; 411-first area; 412-second area; 4121-center of second area; 4122-edge of second area; 42-isolation part; 5-light absorption structure; 51-first nanostructure part; 511-first protrusion; 512-second protrusion; 6-spectrometric structure; 61-second nanostructure part; 611-third protrusion; 612-fourth protrusion; 7-isolation part; 10-non-target area; 20-target area;

[0027] L1-first spacing; L2-second spacing; L3-third spacing; L4-fourth spacing; L5-fifth spacing; L6-sixth spacing; D1-first diameter; D2-second diameter; D3-third diameter; D4-fourth diameter; D5-fifth diameter; D6-sixth diameter. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the description of the embodiments of the present application, unless otherwise specified, "plurality" refers to two or more.

[0030] The terms "first", "second", etc. are used for descriptive purposes only and should not be understood to imply or suggest relative importance or implicitly indicate the number of technical features indicated. Features qualified as "first" or "second" may explicitly or implicitly include one or more of the features.

[0031] "Connect" should be understood in a broad sense, for example, "connect" can be detachably connected or non-detachably connected; it can be directly connected or indirectly connected through an intermediate medium. "Fix" should also be understood in a broad sense, for example, "fix" can be directly fixed or indirectly fixed through an intermediate medium.

[0032] The directional terms mentioned in the embodiments of the present application, such as "upper", "lower", "front", "back", "left", "right", "inner", "outer", "side", "top", "bottom", etc., are only reference directions of the drawings. The directional terms are for better and clearer explanation and understanding of the embodiments of the present application, and do not explicitly or implicitly indicate that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, etc., and therefore cannot be understood as limiting the embodiments of the present application.

[0033] In the drawings of the embodiments of the present application, the center position of the second area, the edge position of the second area, and the center position of the light source are merely schematic and do not represent any limitation on the actual product.

[0034] Nowadays, with the development of optical technology, the application scope of the technology of obtaining structured light through laser projection modules is getting wider and wider. Structured light is a projection formed by projecting a specific light spot onto the surface of an object, and is collected by a receiving module. The position and depth information of the object are calculated according to the changes in the light signal caused by the object, and then the entire depth space is restored. Its application scope is becoming more and more extensive, such as face recognition, gesture recognition, projectors, three-dimensional contour reproduction, depth measurement, anti-counterfeiting identification, etc. Therefore, the quality of structured light is related to the accuracy of the final result of the instrument and equipment. However, the light spot projected by the existing laser projection module has the problems of low contrast and low energy efficiency.

[0035] Figure 1is a schematic diagram of the structure of the laser projection module 1 provided in an embodiment of the present application, Figure 2 is a schematic diagram of the structure of the optical element 4 provided in the embodiment of the present application, combined with Figure 1 and Figure 2 As shown, the laser projection module 1 of the embodiment of the present application includes a light source 2, a base 3 and an optical element 4, the light source 2 is located in the inner cavity 31 of the base 3, and the light source 2 can be used to emit a light spot outside the inner cavity 31. Schematically, the light source 2 can be a vertical cavity surface emitting laser (Vertical-Cavity Surface-Emitting Laser, VCSEL). The optical element 4 can be mounted on the part of the base 3 surrounding the inner cavity 31. The optical element 4 can cover the opening of the inner cavity 31, and the optical element 4 can have a first area 411 and a second area 412. In a possible embodiment, the optical element 4 can have a relative light incident surface 41 and a light exit surface, and the light incident surface 41 can cover the opening 311 of the inner cavity 31 and face the light source 2. The light incident surface 41 can have a first area 411 and a second area 412, and the light incident surface 41 can also have other areas except the first area 411 and the second area 412. In another possible embodiment, the first area 411 and the second area 412 can also be located at the light exit surface at the same time. In another possible implementation, the number of the first region 411 and the second region 412 may be at least two, at least one first region 411 and at least one second region 412 may be located on the light incident surface 41, and at least one first region 411 and at least one second region 412 may be located on the light emitting surface. In another possible implementation, the first region 411 and the second region 412 may be located on different planes, for example, the first region 411 and the second region 412 may be located on the light incident surface 41 and the light emitting surface, respectively.

[0036] Combination Figure 1 and Figure 2As shown, the optical element 4 may include a light absorption structure 5 arranged in the first area 411 and a light splitting structure 6 arranged in the second area 412. The light absorption structure 5 can be used to absorb the light emitted from the light source 2 to the first area 411, and the light absorption structure 5 may include a plurality of protruding nanostructures 51. Schematically, the nanostructure 51 may be located on the light incident surface 41 and protrude toward the light source 2. The plurality of nanostructures 51 may be used to be spaced and set to a specific distribution ratio (described in detail below) so that the transmittance of the light emitted to the first area 411 is lower than the transmittance threshold of the optical element 4. The intervals between any two adjacent nanostructures 51 may be the same or different. Schematically, the nanostructure 51 may be a nanocolumn, and the material of the nanostructure 51 may be silicon. It should be pointed out that the size of the nanostructure 51 is nanometer-scale, and the size of the nanostructure relative to the laser projection module shown in the drawings of the embodiments of the present application is only a schematic display and does not represent its final physical form. By providing a light-absorbing structure 5 having a plurality of spaced nanostructure portions 51 in the first region 411, the plurality of spaced nanostructure portions 51 can, by virtue of their tiny size, cause the light to be reflected and scattered multiple times on the surface or inside of the nanostructure portion 51, thereby increasing the interaction time between the light and the substance, and allowing more light to be captured and absorbed by the light-absorbing structure 5. In addition, the surface plasmon resonance mode inside the nanostructure portion 51 can also cause a locally enhanced electric field effect, further improving the light absorption efficiency of the light-absorbing structure 5. The spectroscopic structure 6 can be used to shape the light emitted from the light source 2 to the second region 412 to form a uniform light spot. Schematically, the shape of the light spot can be stripe-shaped, regular dot-shaped, grid-shaped, speckle-shaped, and more complex shapes, etc.

[0037] In another possible implementation, the nanostructure 51 may also be located on the light-emitting surface of the optical element 4 and protrude in a direction away from the light source 2, that is, the light-absorbing structure 5 of the first region 411 is disposed on the light-emitting surface of the optical element 4. This can also capture and absorb the light incident on the first region 411.

[0038] Combination Figure 1 and Figure 2As shown, the embodiment of the present application is to set an optical element 4 including a light absorption structure 5 and a light splitting structure 6 in the laser projection module 1, wherein the light absorption structure 5 is located in the first area 411 of the light incident surface 41 of the optical element 4, and the light splitting structure 6 is located in the second area 412 of the light incident surface 41 of the optical element 4. The light absorption structure 5 has a plurality of spaced nanostructures 51, so that the light emitted by the light source 2 to the first area 411 can be reflected and scattered multiple times on the surface or inside of the nanostructure 51, that is, at least part of the light emitted by the light source 2 to the first area 411 can be captured and absorbed by the light absorption structure 5, so that the light emitted by the light source 2 to the second area 412 can form a uniform light spot under the shaping of the light splitting structure 6, avoiding the crosstalk and interference of the light emitted to the first area 411 with the light emitted to the second area 412, and finally improving the contrast and energy utilization of the light spot projected by the laser projection module 1.

[0039] Figure 3 is a transmittance curve diagram of multiple nanostructures 51 provided in the embodiment of the present application, combined with Figure 1 , Figure 2 and Figure 3 As shown, in a possible implementation, the ratio of the diameter of the current nanostructure part 51 to the spacing between the center of the current nanostructure part 51 and the center of the adjacent nanostructure part 51 is 0.54-0.61, or 0.69-0.80, and the above ratio is referred to as the new concept duty cycle in the embodiment of the present application. When the above ratio range meets 0.54-0.61, or 0.69-0.80, the transmittance of multiple nanostructure parts 51 is close to 0, that is, the light directed to the first area 411 provided with the light absorption structure 5 is almost completely absorbed by the light absorption structure 5 (described in detail below in conjunction with the accompanying drawings). This helps to avoid crosstalk and interference of the light directed to the first area 411 with the light directed to the second area 412, and ultimately improves the contrast and energy utilization of the light spot projected by the laser projection module 1.

[0040] Combination Figure 1 , Figure 2 and Figure 3 As shown in FIG. 1 , in a possible implementation manner, the plurality of nanostructures 51 may have the same first diameter D1, and a relatively simple mold may be used to prepare the plurality of nanostructures 51 of the same size, thereby reducing the difficulty of processing the optical element 4. The plurality of nanostructures 51 may have a first spacing L1 between them, such as Figure 2 As shown by the dotted line in FIG. 1 , the first spacing L1 may be the interval between the two center lines (dotted lines) of any two adjacent nanostructures 51. The ratio of the first diameter D1 to the first spacing L1 may be the new concept of duty ratio proposed in the embodiment of the present application. Figure 3As shown, when the new concept duty cycle is 0.54-0.61, the transmittance of the multiple nanostructure parts 51 is close to 0, that is, the light directed to the first area 411 provided with the light absorbing structure 5 is almost completely absorbed by the light absorbing structure 5. The embodiment of the present application further enhances the absorptivity of the light absorbing structure 5 by making the ratio of the diameter of the nanostructure part 51 to the distance between the centers of any two adjacent nanostructure parts 51 be 0.54-0.61. For example, the ratio of the first diameter D1 to the first distance L1 can be 0.54, or 0.575, or 0.61. It can be understood that the ratio of the first diameter D1 to the first distance L1 can also be other values ​​in addition to the above values, as long as the ratio of the first diameter D1 to the first distance L1 is in the range of 0.54-0.61. This helps to avoid crosstalk and interference of the light emitted to the first area 411 with the light emitted to the second area 412 , and ultimately improves the contrast and energy utilization of the light spot projected by the laser projection module 1 .

[0041] Combination Figure 1 , Figure 2 and Figure 3 As shown in FIG. 1 , in a possible implementation manner, the ratio of the diameter of the nanostructure portion 51 to the distance between the centers of any two adjacent nanostructure portions is 0.69-0.80. Figure 3 As shown, when the new concept duty cycle is 0.69-0.80, the transmittance of the multiple nanostructure parts 51 is close to 0, that is, the light directed to the first area 411 provided with the light absorbing structure 5 is almost completely absorbed by the light absorbing structure 5, which further enhances the light absorption rate of the light absorbing structure 5. For example, the ratio of the first diameter D1 to the first spacing L1 can be 0.69, or 0.745, or 0.80. It can be understood that the ratio of the first diameter D1 to the first spacing L1 can also be other values ​​in addition to the above values, as long as the ratio of the first diameter D1 to the first spacing L1 is in the range of 0.69-0.80. This is conducive to avoiding crosstalk and interference of the light directed to the first area 411 with the light directed to the second area 412, and ultimately improves the contrast and energy utilization of the light spot projected by the laser projection module 1.

[0042] Figure 4 is a schematic structural diagram of an optical element 4 provided in another embodiment of the present application, Figure 5 yes Figure 4 The physical picture of the optical element 4 shown in FIG. Figure 1 , Figure 3 , Figure 4 and Figure 5As shown, in a possible embodiment, the nanostructure portion 51 may include a first protrusion 511 and a second protrusion 512 that are spaced apart. The spacing between the center lines of any two adjacent first protrusions 511 and second protrusions 512 may be the second spacing L2, or the third spacing L3, and the second spacing L2 is not equal to the third spacing L3. Schematically, the spacing between the first protrusion 511 and the second protrusion 512 in each nanostructure portion 51 may be the third spacing L3. There are also adjacent first protrusions 511 and second protrusions 512 between any two adjacent nanostructure portions 51, that is, the first protrusion 511 of one nanostructure portion 51 is adjacent to the second protrusion 512 of another nanostructure portion 51, and at this time, the spacing between the adjacent first protrusions 511 and second protrusions 512 may be the second spacing L2. Any first protrusion 511 may have an equal second diameter D2, and any second protrusion 512 may have an equal third diameter D3. As Figure 3 As shown, when the new concept duty cycle is 0.54-0.61, or 0.69-0.80, the transmittance of the plurality of nanostructures 51 is close to 0. Exemplarily, the ratio of the second diameter D2 of the first protrusion 511 to the second spacing L2 is 0.54-0.61, or the ratio of the second diameter D2 of the first protrusion 511 to the second spacing L2 is 0.69-0.80, so that the light directed to the light absorbing structure 5 can be fully reflected and scattered by the surface and interior of the adjacent first protrusion 511 and the second protrusion 512 between the two nanostructures 51. Alternatively, the ratio of the second diameter D2 of the first protrusion 511 to the third spacing L3 is 0.54-0.61, or the ratio of the second diameter D2 of the first protrusion 511 to the third spacing L3 is 0.69-0.80, so that the light directed to the light absorbing structure 5 can be fully reflected and scattered by the surface and interior of the first protrusion 511 and the second protrusion 512 in the same nanostructure part 51. All of the above are conducive to avoiding the crosstalk and interference of the light directed to the first area 411 with the light directed to the second area 412, and ultimately improving the contrast and energy utilization of the light spot projected by the laser projection module 1.

[0043] Combination Figure 1 , Figure 3 , Figure 4 and Figure 5As shown, in a possible implementation manner, the ratio of the third diameter D3 of the second protrusion 512 to the second spacing L2 is 0.54-0.61, or the ratio of the third diameter D3 of the second protrusion 512 to the second spacing L2 is 0.69-0.80, so that the light emitted to the light absorbing structure 5 can be fully reflected and scattered by the surface and interior of the adjacent first protrusion 511 and the second protrusion 512 between the two nanostructure parts 51. Alternatively, the ratio of the third diameter D3 of the second protrusion 512 to the third spacing L3 is 0.54-0.61, or the ratio of the third diameter D3 of the second protrusion 512 to the third spacing L3 is 0.69-0.80, so that the light emitted to the light absorbing structure 5 can be fully reflected and scattered by the surface and interior of the first protrusion 511 and the second protrusion 512 in the same nanostructure part 51. All of the above are conducive to avoiding the crosstalk and interference of the light emitted to the first area 411 with the light emitted to the second area 412 , and ultimately improving the contrast and energy utilization of the light spot projected by the laser projection module 1 .

[0044] In another possible embodiment, the nanostructure part may also include two first protrusions and one second protrusion that are arranged in sequence and spaced apart. The ratio of the diameter of the first protrusion to the spacing between the centers of any two adjacent first protrusions is 0.54-0.61, or 0.69-0.80; the ratio of the diameter of the first protrusion to the spacing between the centers of any two adjacent first protrusions and the second protrusion is 0.54-0.61, or 0.69-0.80; the ratio of the diameter of the second protrusion to the spacing between the centers of any two adjacent first protrusions and the second protrusion is 0.54-0.61, or 0.69-0.80. All of the above situations meet the condition that the transmittance of multiple nanostructures is close to 0. It is beneficial to avoid crosstalk and interference of light directed to the first area with light directed to the second area, and ultimately improve the contrast and energy utilization of the light spot projected by the laser projection module.

[0045] In another possible embodiment, the nanostructure part may also include a first protrusion and two second protrusions arranged in sequence. The ratio of the diameter of the first protrusion to the distance between the centers of any two adjacent first protrusions and the second protrusion is 0.54-0.61, or 0.69-0.80; the ratio of the diameter of the second protrusion to the distance between the centers of any two adjacent second protrusions is 0.54-0.61, or 0.69-0.80; the ratio of the diameter of the second protrusion to the distance between the centers of any two adjacent first protrusions and the second protrusion is 0.54-0.61, or 0.69-0.80. The above situations all meet the conditions for making the transmittance of multiple nanostructures close to 0. It is beneficial to avoid crosstalk and interference of light directed to the first area with light directed to the second area, and ultimately improve the contrast and energy utilization of the light spot projected by the laser projection module.

[0046] In summary, the nanostructure portion may include a plurality of different protrusions, the diameter of each protrusion may be equal or unequal, and the spacing between the centers of any two adjacent protrusions may be equal or unequal, as long as the ratio of the diameter of the current protrusion to the spacing between the centers of the current protrusion and the protrusions adjacent thereto is 0.54-0.61, or 0.69-0.80, the condition of making the transmittance of the plurality of nanostructure portions or the plurality of protrusions close to 0 can be satisfied. It should be pointed out that the duty cycle range values ​​described in the above embodiments are all applicable to light with a wavelength of 940nm. For light with wavelengths in other bands, the corresponding duty cycle value range that makes the transmittance of the nanostructure portion and the plurality of protrusions close to 0 will change accordingly.

[0047] Figure 6 is a schematic diagram of the structure of an optical element 4 provided in another embodiment of the present application, Figure 1 , Figure 3 and Figure 6As shown, in a possible embodiment, the nanostructure part 51 is a first nanostructure part 51, and the light splitting structure 6 may include a plurality of second nanostructure parts 61 that are spaced and protrude toward the light source 2. Schematically, the light splitting structure 6 may be a diffuser. The ratio of the spacing between the centers of any two adjacent first nanostructure parts 51 to the diameter of the first nanostructure part 51 is not equal to the ratio of the spacing between the centers of any two adjacent second nanostructure parts 51 to the diameter of the first nanostructure part 51. The second nanostructure part 61 can be used to shape the light directed to the light splitting structure 6, so that the laser projection module 1 can produce a light spot of a specific shape while achieving high transmittance of the light. The first nanostructure part 51 and the second nanostructure part 61 can be integrally formed. Schematically, the second nanostructure part 61 can also be a nanocolumn, and the material of the second nanostructure part 61 can also be silicon. The first nanostructure part 51 and the second nanostructure part 61 can be obtained by sequentially performing a photolithography process and an etching process on the light absorption structure 5 and the light splitting structure 6 on the light incident surface 41, that is, by a set of process flows. By obtaining the integrally formed first nanostructure part 51 and second nanostructure part 61 through one-time processing, the optical element 4 can have high precision and high reliability, which is beneficial to improve the light absorption effect and light splitting effect of the optical element 4, and finally improve the contrast and energy utilization rate of the light spot projected by the laser projection module 1. In another possible embodiment, the first nanostructure part 51 and the second nanostructure part 61 can be directly obtained on the first area 411 and the second area 412 of the optical element 4 at one time by performing related processes such as photolithography and etching processes on the light incident surface 41 or the light exit surface of the optical element 4.

[0048] Combination Figure 1 , Figure 3 and Figure 6 As shown, in a possible implementation, the ratio of the diameter of the current second nanostructure part 61 to the spacing between the centers of the current second nanostructure part 61 and the second nanostructure part 61 adjacent thereto is 0.3-0.53, or 0.62-0.68, or 0.81-0.85. When the above ratio ranges meet 0.3-0.53, or 0.62-0.68, or 0.81-0.85, the transmittance of the plurality of second nanostructure parts 61 to light can be maintained at more than 90%, that is, most of the light directed to the second area 412 provided with the light splitting structure 6 passes through the optical element 4 (described in detail below in conjunction with the accompanying drawings). This is conducive to improving the utilization rate of the light splitting structure 6 for the light directed to the second area 412, and ultimately improving the contrast and energy utilization rate of the light spot projected by the laser projection module 1.

[0049] Combination Figure 1 , Figure 3 and Figure 6As shown in FIG. 1 , in a possible implementation manner, the plurality of second nanostructures 61 may have the same fourth diameter D4, and a relatively simple mold may be used to prepare the plurality of second nanostructures 61 of the same size, thereby reducing the difficulty of processing the optical element 4. The plurality of second nanostructures 61 may have a fourth spacing L4, such as Figure 6 As shown by the dotted line in FIG. 1 , the fourth interval L4 may be the interval between two center lines (dotted lines) of any two adjacent second nanostructures 61. Figure 3 As shown, when the ratio of the fourth diameter D4 to the fourth spacing L4, that is, the duty cycle is 0.3-0.53, the transmittance of the plurality of second nanostructure parts 61 to light can be maintained at more than 90%, that is, most of the light emitted to the second area 412 provided with the light splitting structure 6 passes through the optical element 4. The embodiment of the present application further enhances the light shaping effect of the light splitting structure 6 by making the ratio of the diameter of the second nanostructure part 61 to the spacing between the centers of any two adjacent second nanostructure parts 61 be 0.3-0.53. For example, the ratio of the fourth diameter D4 to the fourth spacing L4 can be 0.3, or 0.415, or 0.53. It can be understood that the ratio of the fourth diameter D4 to the fourth spacing L4 can also be other values ​​in addition to the above values, as long as the ratio of the fourth diameter D4 to the fourth spacing L4 is in the range of 0.3-0.53. This is beneficial to improving the utilization rate of the light emitted to the second area 412 by the light splitting structure 6, and ultimately improving the contrast and energy utilization rate of the light spot projected by the laser projection module 1.

[0050] Combination Figure 1 , Figure 3 and Figure 6 As shown, in a possible implementation, the ratio of the fourth diameter D4 to the fourth spacing L4, that is, the ratio of the diameter of the second nanostructure portion 61 to the spacing between the centers of any two adjacent second nanostructure portions 61, is 0.62-0.68. For example, the ratio of the fourth diameter D4 to the fourth spacing L4 may be 0.62, or 0.65, or 0.68. It is understandable that the ratio of the fourth diameter D4 to the fourth spacing L4 may also be other values ​​in addition to the above values, as long as the ratio of the fourth diameter D4 to the fourth spacing L4 is in the range of 0.62-0.68. This is conducive to improving the utilization rate of the light irradiated to the second area 412 by the spectroscopic structure 6, and ultimately improving the contrast and energy utilization rate of the light spot projected by the laser projection module 1.

[0051] Combination Figure 1 , Figure 3 and Figure 6As shown, in a possible implementation, the ratio of the fourth diameter D4 to the fourth spacing L4, that is, the ratio of the diameter of the second nanostructure portion 61 to the spacing between the centers of any two adjacent second nanostructure portions 61, is 0.81-0.85. For example, the ratio of the fourth diameter D4 to the fourth spacing L4 may be 0.81, or 0.83, or 0.85. It is understandable that the ratio of the fourth diameter D4 to the fourth spacing L4 may also be other values ​​in addition to the above values, as long as the ratio of the fourth diameter D4 to the fourth spacing L4 is in the range of 0.81-0.85. This is conducive to improving the utilization rate of the light irradiated to the second area 412 by the spectroscopic structure 6, and ultimately improving the contrast and energy utilization rate of the light spot projected by the laser projection module 1.

[0052] Figure 7 is a schematic diagram of the structure of an optical element 4 provided in another embodiment of the present application, Figure 1 , Figure 3 and Figure 7 As shown, in a possible implementation, the second nanostructure portion 61 may include a third protrusion 611 and a fourth protrusion 612 that are spaced apart. The spacing between the center lines of any two adjacent third protrusions 611 and fourth protrusions 612 may be the fifth spacing L5 or the sixth spacing L6, and the fifth spacing L5 is not equal to the sixth spacing L6. Schematically, the spacing between the third protrusion 611 and the fourth protrusion 612 in each second nanostructure portion 61 may be the fifth spacing L5. There are also adjacent third protrusions 611 and fourth protrusions 612 between any two adjacent second nanostructure portions 61, that is, the third protrusion 611 of one second nanostructure portion 61 is adjacent to the fourth protrusion 612 of another second nanostructure portion 61, and at this time, the spacing between the adjacent third protrusions 611 and fourth protrusions 612 may be the fifth spacing L5. Any third protrusion 611 may have an equal fifth diameter D5, and any fourth protrusion 612 may have an equal sixth diameter D6. As Figure 3As shown, when the new concept duty cycle is 0.3-0.53, or 0.62-0.68, or 0.81-0.85, the transmittance of light can be maintained above 90%, that is, most of the light emitted to the second area 412 where the light splitting structure 6 is set passes through the optical element 4. Exemplarily, the ratio of the fifth diameter D5 of the third protrusion 611 to the fifth spacing L5 is 0.3-0.53, or 0.62-0.68, or 0.81-0.85, so that the light emitted to the light splitting structure 6 can be fully bundled by the adjacent third protrusion 611 and the fourth protrusion 612 between the two second nanostructure parts 61, and it is beneficial to improve the utilization rate of the light splitting structure 6 for the light emitted to the second area 412. Alternatively, the ratio of the fifth diameter D5 of the third protrusion 611 to the sixth spacing L6 is 0.3-0.53, or 0.62-0.68, or 0.81-0.85, so that the light emitted to the light splitting structure 6 can be fully bundled by the adjacent third protrusions 611 and fourth protrusions 612 between the same second nanostructure part 61, and it is beneficial to improve the utilization rate of the light splitting structure 6 for the light emitted to the second area 412. All of the above are beneficial to improve the utilization rate of the light splitting structure 6 for the light emitted to the second area 412, and ultimately improve the contrast and energy utilization rate of the light spot projected by the laser projection module 1.

[0053] Combination Figure 1 , Figure 3 and Figure 7 As shown, in a possible implementation manner, the ratio of the sixth diameter D6 of the fourth protrusion 612 to the fifth spacing L5 is 0.3-0.53, or 0.62-0.68, or 0.81-0.85, so that the light emitted to the light-splitting structure 6 can be fully bundled by the adjacent third protrusion 611 and the fourth protrusion 612 between the two second nanostructure parts 61, and it is beneficial to improve the utilization rate of the light-splitting structure 6 for the light emitted to the second area 412. Alternatively, the ratio of the sixth diameter D6 of the fourth protrusion 612 to the sixth spacing L6 is 0.3-0.53, or 0.62-0.68, or 0.81-0.85, so that the light emitted to the light-splitting structure 6 can be fully bundled by the adjacent third protrusion 611 and the fourth protrusion 612 between the same second nanostructure part 61, and it is beneficial to improve the utilization rate of the light-splitting structure 6 for the light emitted to the second area 412. All of the above are beneficial to improving the utilization rate of the light emitted to the second area 412 by the light splitting structure 6, and ultimately improving the contrast and energy utilization rate of the light spot projected by the laser projection module 1.

[0054] In another possible implementation, the nanostructure portion may further include two third protrusions and one fourth protrusion that are sequentially spaced apart. The ratio of the diameter of the third protrusion to the spacing between the centers of any two adjacent third protrusions is 0.3-0.53, or 0.62-0.68, or 0.81-0.85; the ratio of the diameter of the third protrusion to the spacing between the centers of any two adjacent third and fourth protrusions is 0.3-0.53, or 0.62-0.68, or 0.81-0.85; the ratio of the diameter of the fourth protrusion to the spacing between the centers of any two adjacent third and fourth protrusions is 0.3-0.53, or 0.62-0.68, or 0.81-0.85. All of the above situations satisfy the condition that the transmittance of multiple second nanostructure portions to light can be maintained at more than 90%. This is beneficial to improving the utilization rate of the light emitted to the second area by the light splitting structure, and ultimately improving the contrast and energy utilization rate of the light spot projected by the laser projection module.

[0055] In another possible embodiment, the nanostructure portion may further include a third protrusion and two fourth protrusions that are sequentially spaced apart. The ratio of the diameter of the third protrusion to the spacing between the centers of any two adjacent third and fourth protrusions is 0.3-0.53, or 0.62-0.68, or 0.81-0.85; the ratio of the diameter of the fourth protrusion to the spacing between the centers of any two adjacent fourth protrusions is 0.3-0.53, or 0.62-0.68, or 0.81-0.85; the ratio of the diameter of the fourth protrusion to the spacing between the centers of any two adjacent third and fourth protrusions is 0.3-0.53, or 0.62-0.68, or 0.81-0.85. The above situations all meet the conditions for maintaining the light transmittance of multiple second nanostructure portions above 90%. This is beneficial to improving the utilization rate of the light emitted to the second area by the light splitting structure, and ultimately improving the contrast and energy utilization rate of the light spot projected by the laser projection module.

[0056] In summary, the second nanostructure portion may include a plurality of different protrusions, the diameter of each protrusion may be equal or unequal, and the spacing between the centers of any two adjacent protrusions may be equal or unequal. As long as the ratio of the diameter of the current protrusion to the spacing between the centers of the current protrusion and the protrusion adjacent thereto is 0.3-0.53, or 0.62-0.68, or 0.81-0.85, the condition that the transmittance of the plurality of second nanostructure portions or the plurality of protrusions to light can be maintained at more than 90% can be satisfied. It should be pointed out that the duty cycle range values ​​described in the above embodiments are all applicable to light with a wavelength of 940nm. For light with wavelengths in other bands, the corresponding duty cycle value range that enables the transmittance of the plurality of second nanostructure portions or the plurality of protrusions to light to be maintained at more than 90% will change accordingly. Figure 8 is a schematic diagram of the structure of an optical element 4 provided in another embodiment of the present application, Figure 1 and Figure 8 As shown, in a possible implementation, the spectroscopic structure 6 may have a plurality of step portions 62 arranged in sequence in a direction perpendicular to the light incident surface, for example, the step portion 62 may include 4 steps. Each step may correspond to a different phase value, for example, the phase value of the first step may be 0, and the phase value of the fourth step may be 2π, and the phase or height of the steps of the same order remain consistent. The adjacent 4 steps from high to low can be called a group of steps, and the width of each group of steps gradually decreases from the center to the edge of the spectroscopic structure 6. The more the number of step portions 62, the higher the utilization rate of the spectroscopic structure 6 for the light directed to the second area 412. Schematically, the spectroscopic structure 6 may be a diffractive optical element. By providing a plurality of spaced nanostructure portions on the light absorption structure 5, and providing a plurality of step portions 62 on the spectroscopic structure 6, the contrast and energy utilization rate of the light spot projected by the laser projection module 1 can be improved.

[0057] Fig. 9 is a schematic diagram of an application scenario of the laser projection module 1 provided in an embodiment of the present application, combined with Figure 2 and Fig. 9 As shown, in a possible implementation, the center 4121 of the second area 412 is directly opposite to the light source 2, so that the light within the effective divergence angle emitted by the light source 2 to the second area 412 can be shaped by the light splitting structure 6, which is beneficial to improving the contrast and energy utilization of the light spot projected by the laser projection module 1. The first area 411 surrounds and wraps the second area 412, that is, there is no gap between the first area 411 and the second area 412, so that the light absorption structure 5 can fully absorb the incident light entering the area outside the second area 412, avoiding crosstalk and interference of other light on the light emitted to the second area 412, and finally improving the contrast and energy utilization of the light spot projected by the laser projection module 1.

[0058] Combination Figure 2 and Fig. 9 As shown, in a possible implementation, the first angle θ1 formed by the direction between the edge 4122 of the second area and the light source 2 and the orientation of the light source 2 can be 18-24°, which is conducive to the second area 412 fully receiving the light within the effective divergence angle from the light source 2. Schematically, the light source 2 can be a vertical cavity surface emitting laser (VCSEL), and the VCSEL light source adopts D86, that is, the 86% boundary of the total energy is used as the divergence angle boundary of the light source 2. For example, the VCSEL divergence angle is 21°, which means that the boundary of 86% of the spot energy can be defined by the first angle θ1, and the first angle θ1 is 21°. The light transmitted along the first angle θ1 and within the first angle θ1 can obtain a light spot of a certain area through the splitting structure 6 of the second area 412, for example Fig. 9 The target area 20 shown. There is still energy outside the boundary defined by the effective divergence angle, accounting for about 14% of the total energy, which means that the boundary of 86% of the spot energy can be defined by the second angle θ2. The light transmitted along the second angle θ2 and outside the second angle θ2 can be fully absorbed by the nanostructure part 51 through the light absorption structure 5 of the first area 411, for example Fig. 9 The non-target area 10 is shown. By making the first angle θ1 formed by the direction between the edge of the second area 412 and the light source 2 and the direction of the light source 2 18-24°, the nanostructure portion 51 of the light absorption structure 5 can fully absorb the light incident into the first area 411, and the light splitting structure 6 can fully shape the light incident into the second area 412, which is beneficial to improving the contrast and energy utilization of the light spot projected by the laser projection module 1.

[0059] Combination Figure 2 and Fig. 9As shown, in a possible implementation, the optical element 4 may have an isolation portion 42 mounted on the base 3. The isolation portion 42 may be used to assemble the optical element 4 to the base 3 so that the base 3 provides support for the optical element 4. A portion of the isolation portion 42 may abut against the base 3, and another portion of the isolation portion 42 may be suspended, and the portion of the isolation portion 42 suspended may be located between the first area 411 and the base 3. In another possible implementation, the isolation portion 42 may be completely suspended, and the isolation portion 42 may be located between the first area 411 and the base 3. That is, at least a portion of the isolation portion 42 may be located between the first area 411 and the base 3, and the surface of the isolation portion 42 is smooth to prevent capillary overflow from causing damage to the function of the optical element 4. The capillary overflow phenomenon refers to the adhesive at any part that can be bonded, such as the adhesive on the base 3. If the optical element 4 contacts the adhesive, the capillary phenomenon of the micro-nano structure will cause the adhesive to spread to the microstructure of the optical element 4, such as the nanostructure portion 51, so that the function of the optical element 4 is damaged. Schematically, the material of the isolation portion 42 may be silicon to avoid the presence of a capillary structure on the surface of the isolation portion 42. This is ultimately beneficial to improving the contrast and energy utilization of the light spot projected by the laser projection module 1.

[0060] Fig.10 This is a comparison diagram of the projection effects of a conventional laser projection module and a laser projection module 1 provided in an embodiment of the present application. Figure 2 , Fig. 9 and Fig.10 As shown, the embodiment of the present application is to set an optical element 4 including a light absorption structure 5 and a light splitting structure 6 in the laser projection module 1, wherein the light absorption structure 5 is located in the first area 411 of the light incident surface 41 of the optical element 4, and the light splitting structure 6 is located in the second area 412 of the light incident surface 41 of the optical element 4. The light absorption structure 5 has a plurality of nanostructure parts 51 with a specific width-to-diameter ratio, so that the light emitted by the light source 2 to the first area 411 can be reflected and scattered multiple times on the surface or inside of the nanostructure part 51, that is, at least part of the light emitted by the light source 2 to the first area 411 can be captured and absorbed by the light absorption structure 5, so that the light emitted by the light source 2 to the second area 412 can form a uniform light spot under the shaping of the light splitting structure 6, avoiding the crosstalk and interference of the light emitted to the first area 411 with the light emitted to the second area 412, so that the light spot projected by the laser projection module 1 of the embodiment of the present application is clear and visible, with clear boundaries, high contrast and high energy utilization.

[0061] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A laser projection module, characterized in that: include: light source; A base, wherein the light source is located in an inner cavity of the base; An optical element, wherein the optical element covers the opening of the inner cavity, the optical element has a first area and a second area, the first area surrounds and wraps the second area; the optical element includes a light-absorbing structure arranged in the first area and a light-splitting structure arranged in the second area, the light-absorbing structure is used to absorb the light emitted by the light source to the first area, and the light-splitting structure is used to shape the light emitted by the light source to the second area; the light-absorbing structure includes a plurality of protruding nanostructure parts, and the plurality of nanostructure parts are used to be spaced and arranged at a specific distribution ratio so that the transmittance of the light emitted to the first area is lower than the transmittance threshold of the optical element.

2. The laser projection module according to claim 1, characterized in that: The ratio of the diameter of the nanostructure portion to the distance between the centers of the nanostructure portion and the adjacent nanostructure portion is 0.54-0.61, or 0.69-0.

80.

3. The laser projection module according to claim 2, characterized in that: The diameters of the plurality of nanostructure parts are the same, and the ratio of the diameter of the nanostructure part to the distance between the centers of any two adjacent nanostructure parts is 0.54-0.61, or 0.69-0.

80.

4. The laser projection module according to claim 2, characterized in that: The nanostructure portion includes a first protrusion and a second protrusion arranged at intervals, and the ratio of the diameter of the first protrusion to the distance between the centers of any two adjacent first protrusions and the second protrusion is 0.54-0.61, or 0.69-0.80; the ratio of the diameter of the second protrusion to the distance between the centers of any two adjacent first protrusions and the second protrusion is 0.54-0.61, or 0.69-0.

80.

5. The laser projection module according to claim 1, characterized in that: The nanostructure portion is a first nanostructure portion, the light splitting structure includes a plurality of second nanostructure portions that are spaced and protrude toward the light source, and the first nanostructure portion and the second nanostructure portion are integrally formed.

6. The laser projection module according to claim 5, characterized in that: The ratio of the diameter of the second nanostructure portion to the distance between the centers of the second nanostructure portion and the adjacent second nanostructure portion is 0.3-0.53, or 0.62-0.68, or 0.81-0.

85.

7. The laser projection module according to claim 6, characterized in that: The second nanostructure portion includes a third protrusion and a fourth protrusion arranged at intervals, and the ratio of the diameter of the third protrusion to the distance between the centers of any two adjacent third protrusions and the fourth protrusions is 0.3-0.53, or 0.62-0.68, or 0.81-0.85; the ratio of the diameter of the fourth protrusion to the distance between the centers of any two adjacent third protrusions and the fourth protrusions is 0.3-0.53, or 0.62-0.68, or 0.81-0.

85.

8. The laser projection module according to claim 1, characterized in that: The center of the second area faces the light source.

9. The laser projection module according to claim 8, characterized in that: The angle formed by the direction between the edge of the second area and the light source and the orientation of the light source is 18-24°.

10. The laser projection module according to any one of claims 1 to 9, characterized in that: The optical element has an isolation portion with a smooth surface, and at least a portion of the isolation portion is located between the first region and the base.

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