Projection system

Abstract

The utility model provides a projection system. The projection system comprises: a light emitting member; the structural part is located on a light emitting path of the light emitting part; and the light trapping structure is arranged on the structural member, the light trapping structure comprises a plurality of diffraction units, and the plurality of diffraction units are arranged in a periodic array. According to the utility model, the problem of serious stray light existing in a projection system in the prior art is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of optical imaging equipment, in particular to a projection system. Background Art

[0002] With the development of optical display devices and the increase in market demand, projection technology has gradually attracted people's attention. As the core of projection technology, the projection system is usually used to present effective light in the display area. Most of the remaining ineffective light is converted into heat energy, and a small part leaks in the display area in the form of stray light, resulting in ghost images and abnormal light leakage in the final image, which reduces the image quality, reduces the color purity, and affects the user experience.

[0003] That is to say, the projection system in the prior art has a serious problem of stray light. Utility Model Content

[0004] The main purpose of the utility model is to provide a projection system to solve the problem of serious stray light in the projection system in the prior art.

[0005] In order to achieve the above-mentioned purpose, the utility model provides a projection system, including a light emitting member; a structural member, the structural member is located on the light emitting optical path of the light emitting member; a light trapping structure, the light trapping structure is arranged on the structural member, the light trapping structure includes a plurality of diffraction units, and the plurality of diffraction units are arranged in a periodic array.

[0006] Furthermore, the light trapping structure includes a plurality of light trapping areas, which are concentrically arranged along a direction close to an edge position of the light trapping structure, each light trapping area includes a plurality of diffraction units, and at least one of the density, shape and size of the diffraction units in different light trapping areas is different.

[0007] Furthermore, the light trapping structure includes a plurality of light trapping areas, the plurality of light trapping areas are concentrically arranged, each light trapping area includes a plurality of diffraction units, and the arrangement density of the diffraction units of two adjacent light trapping areas among the plurality of light trapping areas is different.

[0008] Furthermore, along the direction close to the edge position of the light trapping structure, the arrangement density of the diffraction units in the plurality of light trapping regions gradually increases.

[0009] Furthermore, the density, shape and size of the multiple diffraction units in the same light trapping area are the same, and / or the shapes and sizes of the diffraction units in different light trapping areas are the same.

[0010] Furthermore, the light trapping structure comprises a plurality of light trapping areas, the plurality of light trapping areas are concentrically arranged, and the diffraction units of two adjacent light trapping areas among the plurality of light trapping areas have different shapes and / or different heights.

[0011] Furthermore, there are one or more light-trapping structures. When there are multiple light-trapping structures, the multiple light-trapping structures are sequentially stacked along the surface away from the structural component.

[0012] Furthermore, when there are multiple light-trapping structures, the arrangement density of the diffraction units of the same light-trapping structure is the same, and the arrangement density of the diffraction units of different light-trapping structures is different; or the shapes of the diffraction units of the same light-trapping structure are the same, and the shapes of the diffraction units of different light-trapping structures are different.

[0013] Furthermore, the diffraction unit is columnar, and an extension direction of the columnar diffraction unit is perpendicular to the surface of the structural component where the diffraction unit is located.

[0014] Furthermore, a projection shape of the diffraction unit on the surface of the structural component includes one of a circle, a diamond and a cross.

[0015] Furthermore, the light trapping structure is integrally formed with the surface of the structural member, or the light trapping structure has a substrate, a plurality of diffraction units are arranged on the substrate, and a side surface of the substrate away from the diffraction units is connected to the surface of the structural member.

[0016] Applying the technical solution of the utility model, the projection system includes a light emitting member, a structural member and a light trapping structure, wherein the structural member is located on the light emitting path of the light emitting member; the light trapping structure is arranged on the structural member, and the light trapping structure includes a plurality of diffraction units, and the plurality of diffraction units are arranged in a periodic array.

[0017] By arranging a light-trapping structure on a structural member, and the light-trapping structure includes a plurality of diffraction units, and the plurality of diffraction units are arranged in a periodic array, the invalid light incident on the structural member can be regulated by the light-trapping structure, and the plurality of diffraction units arranged in a periodic array can change the direction of the invalid light incident thereon, so that the invalid light propagates in a specific direction and is further transmitted to the outside of the projection system, so that the invalid light is not emitted to the final display area, which is beneficial to reducing the formation of stray light and improving the imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0019] Figure 1 The optical path diagram of the projection system of the first embodiment of the utility model is shown;

[0020] Figure 2 Shows Figure 1 Normalized intensity distribution diagram of invalid light of the projection system in ;

[0021] Figure 3 Shows Figure 1 Schematic diagram of the light trapping structure of the projection system;

[0022] Figure 4 A schematic diagram showing a light trapping structure of a projection system according to a second embodiment of the present utility model is shown;

[0023] Figure 5 A schematic diagram showing a light trapping structure of a projection system according to a third embodiment of the present utility model is shown;

[0024] Figure 6 A schematic diagram of a light trapping structure of a projection system according to a fourth embodiment of the present utility model is shown.

[0025] The above drawings include the following reference numerals:

[0026] 11. DMD chip; 20. Structural parts; 30. Light trapping structure; 31. Diffraction unit; 32. First light trapping area; 33. Second light trapping area; 34. Third light trapping area; 35. First light trapping structure; 36. Second light trapping structure; 37. Third light trapping structure; 40. Dichroic mirror; 50. Compound eye structure; 60. Prism; 70. Lens. DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present utility model will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0029] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0030] In order to solve the problem of serious stray light in the projection system in the prior art, the utility model provides a projection system.

[0031] like Figures 1 to 6 As shown, the projection system includes a light emitting element, a structural element 20 and a light trapping structure 30. The structural element 20 is located on the light emitting path of the light emitting element. The light trapping structure 30 is arranged on the structural element 20. The light trapping structure 30 includes a plurality of diffraction units 31, and the plurality of diffraction units 31 are arranged in a periodic array.

[0032] By setting a light trapping structure 30 on the structural member 20, and the light trapping structure 30 includes a plurality of diffraction units 31, and the plurality of diffraction units 31 are arranged in a periodic array, so that the invalid light incident on the structural member 20 can be regulated by the light trapping structure 30, and the plurality of diffraction units 31 arranged in a periodic array can change the direction of the invalid light incident thereon, so that the invalid light propagates in a specific direction and is further transmitted to the outside of the projection system, so that the invalid light is not emitted to the final display area, which is beneficial to reduce the formation of stray light and improve the imaging quality.

[0033] It should be noted that the light trapping structure 30 in the projection system of the present application is composed of two-dimensionally distributed diffraction units 31, and at least some of the diffraction units 31 have different shapes, sizes, and refractive indices, which need to be determined according to the optical path propagation direction of the specific projection system. The light trapping structure 30 uses micro-nano etching or imprinting technology to process the binary distributed diffraction units 31. Each diffraction unit 31 can have a specific morphology, refractive index, etc., to finely control the wavefront phase distribution of the light. The incident light diffracts after passing through each diffraction unit 31, and interferes at a certain distance to form a specific light intensity distribution.

[0034] It should also be noted that the structural member 20 is located on the light path of the light emitting member, including: the structural member 20 is located in the light emitting direction of the light emitting member and in a direction perpendicular to the light emitting direction of the light emitting member. The light trapping structure 30 is arranged on the structural member 20, specifically, the light trapping structure 30 can be arranged on the inner wall surface of the structural member 20, and can also be arranged on the outer wall surface of the structural member 20.

[0035] Specifically, each diffraction unit 31 is columnar, and the extension direction of the columnar diffraction unit 31 is perpendicular to the surface of the structural member 20 where it is located. By rationally planning the extension direction and structural shape of the diffraction unit 31, it is helpful to ensure the diffraction characteristics of the diffraction unit 31 and ensure the reliability of the use of the diffraction unit 31.

[0036] Specifically, the projection shape of the diffraction unit 31 on the surface of the structural member 20 includes one of a circle, a diamond and a cross. That is to say, the projection shape of the plurality of diffraction units 31 on the surface of the structural member 20 includes one or more of a circle, a diamond and a cross, which can be set according to the actual situation and the diffraction angle to reasonably adjust the diffraction emission direction of light with different incident angles.

[0037] In an optional embodiment of the present application, the light-trapping structure 30 is integrally formed with the surface of the structural member 20, that is, the light-trapping structure 30 is directly processed on the surface of the structural member 20; or the light-trapping structure 30 has a substrate, and a plurality of diffraction units 31 are arranged on one side surface of the substrate, and the side surface of the substrate away from the diffraction units 31 is connected to the surface of the structural member 20, which can be arranged according to actual conditions. Optionally, in an embodiment of the present application, the above-mentioned projection system is a component of an optical machine, and the projection system can specifically be a light-combining system. In the light-combining system, the light-emitting element is a light source, and the light source can be an LED, LD, etc., but not limited to this. The structural member 20 can be any structural member 20 arranged on the light-emitting side of the light source in the light-combining system, such as a lens barrel or a structure for accommodating lenses. In another embodiment of the present application, the above-mentioned projection system can be a projection system having a DMD chip 11, and the DMD chip 11 serves as a light-emitting element to emit image light.

[0038] The projection system of the present application is described below in conjunction with specific embodiments and drawings.

[0039] Embodiment 1

[0040] like Figures 1 to 3 As shown, the projection system of the first embodiment is described.

[0041] like Figure 1 As shown, in this embodiment, the projection system is a light combining system, and the light combining system is a light combining system of an optical machine. The light combining system includes a light source (not shown in the figure), a structural member 20 (not shown in the figure), a compound eye structure 50, a dichroic mirror 40 and a light trapping structure 30, and the light trapping structure 30 is arranged on the surface of the structural member 20. The compound eye structure 50 and the structural member 20 are respectively located on both sides of the dichroic mirror 40, and the line connecting the compound eye structure 50 to the dichroic mirror 40 is perpendicular to the line connecting the structural member 20 to the dichroic mirror 40.

[0042] like Figure 1As shown, the light source includes two, the two light sources are respectively located on both sides of the dichroic mirror 40, the two light sources emit red light and green light respectively, the two light sources are both wide-spectrum light sources, the red light source is arranged opposite to the compound eye structure 50, and the green light source is arranged opposite to the structural member 20, the red light and the green light pass through the dichroic mirror 40, the effective red light is transmitted and propagated, and then reaches the compound eye structure 50, the effective green light is reflected and propagated, and then reaches the compound eye structure 50, the invalid red light and the invalid green light are irradiated on the surface of the structural member 20, and a plurality of diffraction units 31 arranged periodically and in an array are arranged on the surface of the structural member 20, so that the invalid light is Diffraction is generated on multiple diffraction units 31, so that the light is reflected in a specific direction and does not enter the imaging optical path for imaging, and the light intensity distribution is controlled. Specifically, since the incident light itself has a certain intensity distribution, the incident light is scattered by the structural surface after being incident on the structural surface. Since the scattered light is distributed at a wide angle, it is easy to generate stray light at different angles. By setting diffraction units of different densities or different shapes, light output control can be performed corresponding to stray light at different angles, so that stray light at different angles is reflected in a specific direction to reduce the probability of stray light formation, which is beneficial to improving color purity.

[0043] like Figure 2 As shown, it is a normalized intensity distribution diagram of the blue line, green line, yellow line and red line of the projection system of Example 1. In the figure, the circle represents the blue line, and the three long strips represent the green line, yellow line and red line from left to right. In the figure, the yellow line represents the intensity distribution of the incident light, the blue line represents the intensity distribution of the incident light after being scattered by the surface of the general structural member 20, such as the inclined surface, blackened surface, stepped surface or polished surface, and the Gaussian-like intensity distribution formed after being scattered, the green line represents the formation area of ​​the stray light, and the red line represents the intensity distribution of the incident light after being scattered by the light trapping structure 30. It can be seen from the figure that after the incident light is reflected by the surface of the structural member 20, the distribution angle of the scattered light is relatively wide, completely covering the stray light distribution area of ​​the green line, and generating stray light. After the incident light is scattered by the light trapping structure 30, the direction of the outgoing light is regulated by the light trapping structure 30, and the light is emitted in a direction that is not conducive to the formation of stray light, and the angle distribution of the outgoing light is relatively concentrated, thereby reducing the probability of stray light formation.

[0044] Specifically, there is one light trapping structure 30, and one light trapping structure 30 includes multiple light trapping areas, and the multiple light trapping areas are concentrically arranged in the direction close to the edge position of the light trapping structure 30, and each light trapping area includes multiple diffraction units 31, and at least one of the density, shape and size of the diffraction units 31 in different light trapping areas is different. The multiple light trapping areas include a circular area and multiple annular areas, and the circular area is located at the center of the light trapping structure 30. The multiple annular areas are nested with the circular area as the center, and the outer diameters of the multiple annular areas gradually increase in the direction away from the circular area. Since the angles at which light is incident on different light trapping areas have certain differences, the light trapping structure 30 is divided into multiple concentrically arranged light trapping areas, and by changing the density, shape or size of the diffraction units 31 in different light trapping areas, the invalid light at different incident angles can be respectively adjusted, so that the invalid light incident at different angles is emitted in the same preset direction, thereby reducing the formation of stray light. It should be noted here that the shape of the above-mentioned diffraction unit 31 specifically refers to the projection shape of the diffraction unit 31 on the surface on which it is located.

[0045] like Figure 3 As shown in FIG. 1 , in this embodiment, the arrangement density of the diffraction units 31 in two adjacent light trapping areas among the multiple light trapping areas is different, and the arrangement density of the diffraction units 31 in the multiple light trapping areas gradually increases along the direction close to the edge position of the light trapping structure 30. The density, shape and size of the multiple diffraction units 31 in the same light trapping area are the same, and the shapes and sizes of the diffraction units 31 in different light trapping areas are the same. Specifically, referring to FIG. Figure 3 , the multiple light trapping areas at least include a first light trapping area 32, a second light trapping area 33 and a third light trapping area 34 which are arranged concentrically, the first light trapping area 32 is circular and located at the center of the light trapping structure 30, the second light trapping area 33 and the third light trapping area 34 are both in annular shape, the second light trapping area 33 is located between the first light trapping area 32 and the third light trapping area 34, and the inner diameter of the second light trapping area 33 is smaller than the inner diameter of the third light trapping area 34. The diffraction units 31 in the three light trapping areas are all cylindrical, and the arrangement density of the diffraction units 31 from the first light trapping area 32 to the third light trapping area 34 gradually increases. Since the angles at which light rays are incident on different light trapping areas are different, the arrangement density of the diffraction units 31 in each light trapping area is different, so that the control consistency of light rays at different incident angles can be improved, so that light rays at different incident angles can be propagated in the same preset direction, and the probability of stray light formation is reduced. For example, the diffraction units 31 of the third light trapping zone 34 are arranged most densely to cope with light with a large incident angle; the diffraction units 31 of the second light trapping zone 33 are arranged slightly loosely to cope with light with a larger incident angle; and the diffraction units 31 of the first light trapping zone 32 are arranged most loosely to cope with light with a smaller incident angle.

[0046] In addition, by controlling the density, shape and size of the diffraction units 31 in the same light trapping area to be the same, the direction of control of the incident light can be made consistent when the light enters the same light trapping area, thereby making the emission direction of the diffracted light consistent. Different light trapping areas have the same shape and size, and the emission direction of the light can be controlled only by controlling the density of the diffraction units 31 in different light trapping areas. Designing the diffraction units 31 of the same standard can reduce production costs and facilitate manufacturing.

[0047] Embodiment 2

[0048] like Figure 4 FIG. 1 is a schematic diagram of the structure of the light trapping structure 30 of the projection system according to the second embodiment.

[0049] The difference between this embodiment and the first embodiment lies in that the specific structure of the light trapping structure 30 is different.

[0050] Specifically, the light trapping structure 30 includes a plurality of light trapping areas, the plurality of light trapping areas are concentrically arranged, and the diffraction units 31 of two adjacent light trapping areas among the plurality of light trapping areas have different shapes, or different heights, or different shapes and heights.

[0051] exist Figure 4 In the specific embodiment shown, the plurality of light trapping regions at least include a first light trapping region 32, a second light trapping region 33, and a third light trapping region 34 which are arranged concentrically. The first light trapping region 32 is circular and located at the center of the light trapping structure 30. The second light trapping region 33 and the third light trapping region 34 are both in the shape of annular rings. The second light trapping region 33 is located between the first light trapping region 32 and the third light trapping region 34. The inner diameter of the second light trapping region 33 is smaller than the inner diameter of the third light trapping region 34. The shapes of the diffraction units 31 in the same light trapping region are the same, and the shapes of the diffraction units 31 in different light trapping regions are different. Specifically, the projection shape of the plurality of diffraction units 31 in the first light trapping region 32 on the surface of the structural member 20 is a rhombus, the projection shape of the plurality of diffraction units 31 in the second light trapping region 33 on the surface of the structural member 20 is a cross, and the projection shape of the plurality of diffraction units 31 in the third light trapping region 34 on the surface of the structural member 20 is a circle. By reasonably allocating different shapes of the diffraction units 31 in different light trapping zones, different light trapping zones can correspond to light with different incident angles, which can improve the control consistency of light with different incident angles, so that light with different incident angles can propagate in the same preset direction, reducing the probability of stray light formation. For example, the third light trapping zone 34 corresponds to light with a large incident angle; the second light trapping zone 33 corresponds to light with a larger incident angle; and the first light trapping zone 32 corresponds to light with a smaller incident angle. The stacked structure allows incident light of different wavelengths to have better control consistency.

[0052] Optionally, the diffraction units 31 of the three light trapping areas may also be set to different sizes or different heights, which can be adjusted according to actual conditions.

[0053] Embodiment 3

[0054] like Figure 5 FIG. 1 is a schematic diagram of the structure of the light trapping structure 30 of the projection system of the third embodiment.

[0055] The difference between this embodiment and the first or second embodiment is that the number of the light trapping structures 30 is different.

[0056] like Figure 5 As shown, in this embodiment, there are multiple light trapping structures 30, and the multiple light trapping structures 30 are sequentially stacked along the surface away from the structural member 20. Each light trapping structure 30 includes a substrate and multiple diffraction units 31 arranged on one side surface of the substrate.

[0057] Specifically, the multiple light trapping structures 30 include at least a first light trapping structure 35, a second light trapping structure 36 and a third light trapping structure 37, and the first light trapping structure 35 to the third light trapping structure 37 are sequentially stacked in a direction close to the structural member 20. The arrangement density of the diffraction units 31 on different light trapping structures is different, and the arrangement density of the multiple diffraction units 31 of the same light trapping structure is the same. By adjusting the arrangement density of the diffraction units of different light trapping structures, it is achieved that different light trapping structures 30 have the best control effect on incident light of different wavelengths. Or the diffraction units 31 on different light trapping structures have different shapes and the same arrangement density, and the multiple diffraction units 31 of the same light trapping structure have the same shape. By adjusting the shapes of different light trapping structures, different light trapping structures 30 have the best control effect on incident light of different wavelengths, so that light of different wavelengths can propagate in the same preset direction, reducing the probability of stray light formation. In this embodiment, the first light trapping structure 35 can be configured to optimally regulate the incident blue light band, the second light trapping structure 36 can be configured to optimally regulate the incident green light band, and the third light trapping structure 37 can be configured to optimally regulate the incident red light band.

[0058] Embodiment 4

[0059] like Figure 6 , which is a schematic diagram of the structure of the projection system of the fourth embodiment.

[0060] The difference between this embodiment and the first embodiment lies in that the structural composition of the projection system is different, and the light trapping structure 30 is disposed on the inner wall surface of the structural member 20 .

[0061] In this embodiment, the light emitting component of the projection system is a DMD chip 11, and a prism 60, a structural component 20, and a lens 70 are sequentially arranged on the light emitting side of the DMD chip 11. The structural component 20 is a hollow structure, and a light trapping structure 30 is arranged on the surface of the structural component 20. The light emitted by the DMD chip 11 passes through the hollow area of ​​the prism 60 and the structural component 20 in sequence and then enters the lens 70. The light trapping structure 30 in this embodiment can adopt any one of the first to third embodiments.

[0062] In this embodiment, when the DMD chip 11 is in the off state, invalid light is irradiated on the structural member 20, and the surface of the irradiated area has a plurality of diffraction units 31 arranged in a periodic array. The invalid light is diffracted on this surface, so that the light is reflected in a specific direction, such as the direction opposite to the propagation of the effective light or the direction that is not conducive to the formation of stray light, and the light intensity distribution is controlled to reduce the probability of stray light formation, which can improve the contrast and reduce light leakage.

[0063] Obviously, the embodiments described above are only some embodiments of the utility model, not all embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0064] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0065] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0066] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A projection system, characterized in that: include: Light emitting parts; A structural component (20), the structural component (20) being located on the light emitting path of the light emitting component; A light trapping structure (30), wherein the light trapping structure (30) is arranged on the structural component (20), and the light trapping structure (30) comprises a plurality of diffraction units (31), wherein the plurality of diffraction units (31) are arranged in a periodic array.

2. The projection system according to claim 1, characterized in that: The light trapping structure (30) comprises a plurality of light trapping regions, the plurality of light trapping regions are concentrically arranged in a direction close to an edge position of the light trapping structure (30), each of the light trapping regions comprises a plurality of diffraction units (31), and at least one of density, shape and size of the diffraction units (31) in different light trapping regions is different.

3. The projection system according to claim 1, characterized in that: The light trapping structure (30) comprises a plurality of light trapping areas, the plurality of light trapping areas are concentrically arranged, each of the light trapping areas comprises a plurality of diffraction units (31), and the arrangement density of the diffraction units (31) of two adjacent light trapping areas among the plurality of light trapping areas is different.

4. The projection system according to claim 3, characterized in that: Along a direction close to an edge position of the light trapping structure (30), the arrangement density of the diffraction units (31) in the plurality of light trapping areas gradually increases.

5. The projection system according to claim 3, characterized in that: The density, shape and size of the plurality of diffraction units (31) in the same light trapping area are the same, and / or the shapes and sizes of the diffraction units (31) in different light trapping areas are the same.

6. The projection system according to claim 1, characterized in that: The light trapping structure (30) comprises a plurality of light trapping areas, the plurality of light trapping areas are concentrically arranged, and the diffraction units (31) of two adjacent light trapping areas among the plurality of light trapping areas have different shapes and / or different heights.

7. The projection system according to any one of claims 1 to 6, characterized in that: There are one or more light-trapping structures (30). When there are multiple light-trapping structures (30), the multiple light-trapping structures (30) are sequentially stacked along a surface away from the structural component (20).

8. The projection system according to claim 7, characterized in that: When there are multiple light trapping structures (30), The arrangement density of the diffraction units of the same light trapping structure (30) is the same, and the arrangement density of the diffraction units of different light trapping structures (30) is different; or The diffraction units of the same light trapping structure have the same shape, while the diffraction units of different light trapping structures (30) have different shapes.

9. The projection system according to any one of claims 1 to 6, characterized in that: The diffraction unit (31) is columnar, and the extension direction of the columnar diffraction unit (31) is perpendicular to the surface of the structural component (20) where it is located.

10. The projection system according to any one of claims 1 to 6, characterized in that: The projection shape of the diffraction unit (31) on the surface of the structural member (20) includes one of a circle, a diamond and a cross.

11. The projection system according to any one of claims 1 to 6, characterized in that: The light trapping structure (30) is integrally formed with the surface of the structural component (20), or the light trapping structure (30) has a substrate, a plurality of the diffraction units (31) are arranged on the substrate, and a side surface of the substrate away from the diffraction units (31) is connected to the surface of the structural component (20).

Images