Projection screen, projection system, mold and mold mother set

Abstract

A projection screen (10), a projection system (100), a mold (500), and a mold master. Wherein the projection screen (10) comprises a surface layer (11), a reflecting layer (13) and a Fresnel lens layer (12); a plurality of Fresnel microstructures (121) are arranged on one side, close to the reflecting layer (13), of the Fresnel lens layer (12), and the centers of circles of the Fresnel microstructures (121) are the same; the Fresnel microstructure (121) is provided with a first surface (1211) and a second surface (1212) which are connected with each other; the first surface (1211) is obliquely arranged; a first included angle (alpha) formed by the first surface (1211) and the surface, close to one side of the Fresnel lens layer (12), of the surface layer (11) is related to a first target coefficient and a second included angle, the first target coefficient is related to the radius of the Fresnel microstructure (121), and the second included angle is any value in a first range.

Description

Projection screens, projection systems, molds and mold masters

[0001] This application claims priority to Chinese patent application No. 202211028191.3 filed on August 25, 2022, priority to Chinese patent application No. 202211026961.0 filed on August 25, 2022, and priority to Chinese patent application No. 202210899996.9 filed on July 28, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to the field of projection display technology, and in particular to a projection screen, a projection system, a mold, and a mold master. Background Art

[0003] With the continuous development of projection display technology, projection systems are becoming increasingly popular among consumers. Typically, a projection system consists of a projection device and a projection screen. The projection device emits light and projects it onto the projection screen. The light then reflects off the projection screen and reaches the viewer, allowing them to see the image displayed on the projection screen.

[0004] Summary of the Invention

[0005] In one aspect, a projection screen is provided, configured to reflect light emitted by a projection device. The projection screen comprises a surface layer, a reflective layer, and a Fresnel lens layer. The surface layer is configured to protect the projection screen; the reflective layer is configured to reflect light so that the light is emitted from the surface layer; a plurality of Fresnel microstructures are provided on a side of the Fresnel lens layer adjacent to the reflective layer, with the plurality of Fresnel microstructures having the same center; the surface layer, the Fresnel lens layer, and the reflective layer are stacked in sequence; the Fresnel microstructures comprise a first surface and a second surface connected to each other; the first surface is inclined, with the distance between an end of the first surface adjacent to the second surface and the surface layer being greater than the distance between an end of the first surface distal to the second surface and the surface layer; a first angle formed between the first surface and the surface of the surface layer adjacent to the Fresnel lens layer is related to a first target coefficient and a second angle, the first target coefficient being related to the radius of the Fresnel microstructure, and the second angle being any value within a first range.

[0006] In another aspect, a projection system is provided. The projection system includes a projection device and a projection screen. The projection screen is configured to reflect light emitted by the projection device and includes a surface layer, a reflective layer, and a Fresnel lens layer. The surface layer is configured to protect the projection screen; the reflective layer is configured to reflect light so that the light is emitted from the surface layer; a plurality of Fresnel microstructures are provided on a side of the Fresnel lens layer adjacent to the reflective layer, with the plurality of Fresnel microstructures having the same center; the surface layer, the Fresnel lens layer, and the reflective layer are stacked in sequence; the Fresnel microstructure includes a first surface and a second surface connected to each other; the first surface is inclined, with the distance between an end of the first surface adjacent to the second surface and the surface layer being greater than the distance between an end of the first surface distal to the second surface and the surface layer; a first angle formed between the first surface and the surface of the surface layer adjacent to the Fresnel lens layer is related to a first target coefficient and a second angle, the first target coefficient being related to the radius of the Fresnel microstructure, and the second angle being any value within a first range.

[0007] In another aspect, a mold is provided. The mold is used for a projection screen. The mold includes a first sub-mold and a second sub-mold. The first sub-mold includes a first sub-mold body and a plurality of first belt structures; the first sub-mold body has a first structural surface; the plurality of first belt structures are sequentially arranged on the first structural surface; the second sub-mold includes a second sub-mold body and a plurality of second belt structures; the second sub-mold body is connected to the first sub-mold body and has a second structural surface, the second structural surface is connected to the first structural surface and is located on the same plane; the plurality of second belt structures are arranged on the second structural surface and are arranged around the plurality of first belt structures.

[0008] In another aspect, a mold master is provided. The mold master has a Fresnel microstructure. The Fresnel microstructure is formed by embossing the mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG1 is a structural diagram of a projection system in related art;

[0010] FIG2 is a structural diagram of a projection system according to some embodiments;

[0011] FIG3 is a structural diagram of a projection screen according to some embodiments;

[0012] FIG4 is a structural diagram of a Fresnel lens layer according to some embodiments;

[0013] FIG5 is a schematic diagram of light projection of a projection screen according to some embodiments;

[0014] FIG6 is a brightness comparison diagram of a projected image according to some embodiments;

[0015] FIG7 is a structural diagram of another projection screen according to some embodiments;

[0016] FIG8 is a structural diagram of a surface layer according to some embodiments;

[0017] FIG9 is a diagram illustrating a light path of light passing through a surface layer according to some embodiments;

[0018] FIG10 is a light path diagram of a projection screen according to some embodiments;

[0019] FIG11 is another light path diagram of light passing through a surface layer according to some embodiments;

[0020] FIG12 is another schematic diagram of light projection on a projection screen according to some embodiments;

[0021] FIG13 is a schematic diagram of light passing through a surface layer according to some embodiments;

[0022] FIG14 is a structural diagram of a surface layer according to some embodiments;

[0023] FIG15 is a structural diagram of a protrusion according to some embodiments;

[0024] FIG16 is a structural diagram of a reflective layer according to some embodiments;

[0025] FIG17 is a structural diagram of another reflective layer according to some embodiments;

[0026] FIG18 is a structural diagram of a mold according to some embodiments;

[0027] FIG19 is a cross-sectional view of the mold shown in FIG18;

[0028] FIG20 is a structural diagram of the first sub-mold shown in FIG18;

[0029] FIG21 is a structural diagram of the second sub-mold shown in FIG18;

[0030] FIG22 is a flow chart of a method for manufacturing a mold according to some embodiments;

[0031] FIG23 is another flow chart of a method for manufacturing a mold according to some embodiments;

[0032] FIG24 is a structural diagram of a first sub-mold according to some embodiments;

[0033] FIG25 is a structural diagram of a first tapered roller mold according to some embodiments;

[0034] FIG26 is another flow chart of a method for manufacturing a mold according to some embodiments;

[0035] FIG27 is a structural diagram of a second sub-mold according to some embodiments;

[0036] FIG28 is another flow chart of a method for manufacturing a mold according to some embodiments;

[0037] FIG29 is another flow chart of a method for manufacturing a mold according to some embodiments;

[0038] FIG30 is another flow chart of a method for manufacturing a mold according to some embodiments;

[0039] FIG31 is another flow chart of a method for manufacturing a mold according to some embodiments;

[0040] FIG32 is another flowchart of a method for manufacturing a mold according to some embodiments. DETAILED DESCRIPTION

[0041] The following will be combined with the accompanying drawings to clearly and completely describe some embodiments of the present disclosure. Obviously, the embodiments described are only some embodiments of the present disclosure, not all embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present disclosure.

[0042] Unless the context requires otherwise, throughout the specification and claims, the term "comprise" and its other forms, such as the third person singular form "comprises" and the present participle form "comprising", are to be interpreted as open and inclusive, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" are intended to indicate that the particular features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the particular features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0043] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0044] When describing some embodiments, the word "connected" and its derivatives may be used. The term "connected" should be understood broadly. For example, "connected" can mean fixed, removable, or integrated; it can be directly connected or indirectly connected through an intermediary. The embodiments disclosed herein are not necessarily limited to the contents of this document.

[0045] The use of "adapted to" or "configured to" herein is intended to be open and inclusive language that does not exclude devices adapted or configured to perform additional tasks or steps.

[0046] FIG1 is a structural diagram of a projection system in the related art.

[0047] Typically, as shown in FIG1 , a projection system 100 ′ includes a projection screen 10 ′ and a projection device 20 ′. The projection screen 10 ′ includes a Fresnel lens layer. The Fresnel lens layer has multiple concentric Fresnel microstructures. The center O1 ′ of each of the multiple Fresnel microstructures is located outside the projection screen 10 ′. The position of the center O1 ′ of each of the multiple Fresnel microstructures can be set based on the parameters of the projection device 20 ′. For example, the projection device 20 ′ includes a light outlet 23 ′, and the center O1 ′ of each of the multiple Fresnel microstructures is on the same horizontal line as the light outlet 23 ′. Here, the projection device 20 ′ can be an ultra-short-throw projection device.

[0048] A first distance D1' between the center O1' of the multiple Fresnel microstructures and the projection screen 10' is greater than or equal to 170 mm (D1' ≥ 170 mm), allowing the projection screen 10' to be used with an ultra-short-throw projection device. For example, if the projection device 20' is 80 inches, has a throw ratio of 0.25, and an offset of 145%, the first distance D1' between the center O1' of the multiple Fresnel microstructures and the projection screen 10' is approximately 224 mm.

[0049] The off-axis is the ratio of a third distance D3' between the orthographic projection O2' of the light outlet 23' on the plane of the projection screen 10' and the center O' of the projection screen 10', to a fourth distance D4' between the center O' of the projection screen 10 and the side edge of the projection screen 10' closer to the projection device 20' (OFFSET = D3' / D4'). In other words, the off-axis is the ratio of the sum of the first distance D1' and the fourth distance D4' to the fourth distance D4' (OFFSET = (D1'+D4') / D2').

[0050] It should be noted that, since the center O1' of the multiple Fresnel microstructures and the light outlet 23' are on the same horizontal line, the orthographic projection O2' of the light outlet 23' on the plane where the projection screen 10' is located can be located at the position where the center O1' of the multiple Fresnel microstructures is located. For example, as shown in FIG1 , the center O1' of the multiple Fresnel microstructures coincides with the orthographic projection O2' of the light outlet 23' on the plane where the projection screen 10' is located. Furthermore, the second distance D2' between the orthographic projection O2' of the light outlet 23' on the plane where the projection screen 10' is located and the projection screen 10' is the same as the first distance D1' between the center O1' of the multiple Fresnel microstructures and the projection screen 10' (D2'=D1'). Here, the first distance D1', the second distance D2', the third distance D3', and the fourth distance D4' are respectively the shortest distances.

[0051] By adopting the above-mentioned Fresnel microstructure, the uniformity of the projection screen 10' can reach about 75%. However, in actual applications, the surface of the projection screen 10' is usually not a smooth and flat surface. After the light is emitted from the projection screen 10', it will undergo a certain deflection, and part of the light will be deflected toward the outside of the projection screen 10', reducing the uniformity of the projection screen 10'. For example, the uniformity of the projection screen 10' is less than 70%. The uniformity of the projection screen 10' is low and cannot meet actual needs. The uniformity can be the degree of balance of the brightness of the projected image on the projection screen. For example, 9 points are selected on the projection screen, and the uniformity of the projection screen is determined based on the brightness of the reflected light at these 9 points.

[0052] In order to solve the above problems, some embodiments of the present disclosure provide a projection system 100 .

[0053] FIG. 2 is a structural diagram of a projection system according to some embodiments.

[0054] In some embodiments, as shown in FIG. 2 , the projection system 100 includes a projection device 20 and a projection screen 10 .

[0055] For the convenience of describing the projection system 100 , the side of the projection screen 10 facing the audience 30 is defined as the front side, and the opposite side is defined as the rear side.

[0056] As shown in FIG2 , projection device 20 is located on a side of projection screen 10 (e.g., the front side) that is close to viewer 30 and below projection screen 10. Thus, projection device 20 is disposed in front of and below projection screen 10 and has a light outlet 23 through which incident light 21 is emitted toward projection screen 10. Viewer 30 is located in front of and facing projection screen 10. Projection device 20 emits incident light 21 that is incident on projection screen 10. After being reflected by projection screen 10, incident light 21 forms outgoing light 22 that enters the eyes of viewer 30 and forms an image on projection screen 10.

[0057] In some embodiments, the projection device 20 may include a laser, and the laser may be any one of a monochromatic laser, a dual-color laser, and a tri-color laser. The tri-color laser may emit a blue laser beam, a red laser beam, and a green laser beam. For example, the wavelength of the blue laser beam is in the range of 430 nm to 460 nm, the wavelength of the green laser beam is in the range of 500 nm to 540 nm, and the wavelength of the red laser beam is in the range of 610 nm to 650 nm.

[0058] Since a three-color laser has the characteristics of true color and a high color gamut, the laser can be a three-color laser. Of course, the present disclosure is not limited to this, and the laser can also be a monochromatic laser or a two-color laser.

[0059] The structure of the projection screen 10 provided in some embodiments of the present disclosure is described below by way of example.

[0060] FIG3 is a structural diagram of a projection screen according to some embodiments.

[0061] As shown in FIG3 , the projection screen 10 includes a surface layer 11, a Fresnel lens layer 12, and a reflective layer 13, which are stacked in sequence. The surface layer 11 is located adjacent to the projection device 20 and is configured to protect the projection screen 10 from damage. The surface layer 11 can be made of a hard material to form a hard protective layer. The reflective layer 13 is configured to reflect incident light 21 so that the incident light 21 is emitted from the surface layer 11 as outgoing light 22. For example, a reflective material is distributed within the reflective layer 13 so that the incident light 21 is reflected by the reflective layer 13. The Fresnel lens layer 12 has a plurality of concentrically arranged Fresnel microstructures 121 on one side thereof, adjacent to the reflective layer 13.

[0062] The center O1 of the multiple Fresnel microstructures 121 is located outside the projection screen 10. The orthographic projection O2 (target projection O2) of the light outlet 23 on the plane of the projection screen 10 is located on the side of the center O1 of the multiple Fresnel microstructures 121 away from the projection screen 10 (e.g., below). In this case, the first distance D1 between the center O1 of the multiple Fresnel microstructures and the projection screen 10 is less than the second distance D2 between the orthographic projection O2 of the light outlet 23 on the plane of the projection screen 10 and the projection screen 10 (D1 < D2). In the related art, as shown in FIG. 1 , the first distance D1' is equal to the second distance D2' (D1' = D2'). Therefore, the first distance D1 between the center O1 of the multiple Fresnel microstructures 121 and the projection screen 10 is reduced, and the first distance D1 is less than the first distance D1'. As a result, the radius of the multiple Fresnel microstructures 121 can be smaller than the radius of the Fresnel microstructures in FIG. 1 , and the radius of the multiple Fresnel microstructures 121 can be reduced.

[0063] It should be noted that the Fresnel microstructure 121 can make the light converge toward the center of the projection screen 10 , and the smaller the radius of the Fresnel microstructure 121 , the higher the degree to which the light converges toward the center of the projection screen 10 .

[0064] In this way, when the incident light 21 emitted by the projection device 20 passes through the multiple Fresnel microstructures 121, the outgoing light 22 can converge toward the center of the projection screen 10. Therefore, when the viewer 30 is located at a position facing the projection screen 10, the viewer 30 can view an image with higher brightness. As shown in Figure 3, when the ambient light 61 emitted by the ambient light source 60 passes through the Fresnel lens layer 12, it will be reflected to an area outside the human eye's view, reducing the interference of the ambient light 61.

[0065] In addition, compared with the related art in which the center O1' of multiple Fresnel microstructures coincides with the orthographic projection O2' of the light outlet 23' on the plane where the projection screen 10' is located, at the same position on the projection screen 10, the radius of the Fresnel microstructure 121 in Figure 3 is reduced, so that the incident light 21 can converge toward the center of the projection screen 10, thereby improving the uniformity of the projection screen 10.

[0066] In some embodiments, as shown in FIG3 , the cross-section of the Fresnel microstructure 121 can be triangular. In other words, the structure of the Fresnel microstructure 121 can be a triangular prism. One surface of the Fresnel microstructure 121 (e.g., the surface facing away from the surface layer 11) is inclined, while the other surface of the Fresnel microstructure 121 (e.g., the surface facing closer to the surface layer 11) is vertically arranged. These two surfaces form a first angle α, the magnitude of which can be adjusted based on practical needs. Furthermore, a template with a smaller eccentricity distance (first distance D1) can be selected to fabricate the Fresnel lens layer 12.

[0067] FIG. 4 is a structural diagram of a Fresnel lens layer according to some embodiments.

[0068] In some embodiments, as shown in FIG4 , when the projection screen 10 is rectangular, the Fresnel lens layer 12 is also rectangular. The center O1 of the multiple Fresnel microstructures 121 is located on the central axis L1 of the projection screen 10. The central axis L1 of the projection screen 10 is also the central axis L2 of the Fresnel lens layer 12. The central axis L1 of the projection screen 10 is parallel to the vertical direction and perpendicular to the longitudinal direction of the projection screen 10 (e.g., the front-to-back direction in FIG4 ).

[0069] Since the center O1 of the Fresnel microstructure 121 is located on the central axis of the projection screen 10, the outgoing light 22 can converge toward the center of the projection screen 10, so that the brightness of the light near the center of the projection screen 10 is more uniform, and the brightness uniformity of the projection screen 10 is better.

[0070] Furthermore, the orthographic projection O2 of the light outlet 23 onto the plane of the projection screen 10 can also be located on the central axis L1 of the projection screen 10. In this way, the center of the projected image projected by the projection device 20 can coincide with the center of the projection screen 10, thereby allowing the incident light 21 emitted by the projection device 20 to be projected onto the projection screen 10 to the greatest extent possible. As shown in FIG3 , if the projection screen 10 is rectangular, the width direction of the projection screen 10 is the vertical direction in FIG3 (i.e., the height direction when the viewer 30 is viewing the screen).

[0071] The following describes an example of light projection of the projection screen 10 provided in some embodiments of the present disclosure.

[0072] FIG5 is a schematic diagram of light projection for a projection screen according to some embodiments.

[0073] As shown in FIG. 5 , the light is emitted from the light outlet 23 and is incident on the projection screen 10 . After being reflected by the projection screen 10 , the light is reflected to the target plane S.

[0074] In Figure 5 , a first dotted line A1 represents a Fresnel microstructure 121 in the projection screen 10. Light reflected from this Fresnel microstructure 121 is incident on a first position A11 on the target plane S. A second dotted line A2 represents another Fresnel microstructure at the same position on a projection screen 10 of the same size. This Fresnel microstructure has a larger radius than the Fresnel microstructure 121 corresponding to the first dotted line A1. Light reflected from the Fresnel microstructure corresponding to the second dotted line A2 is incident on a second position A21 on the target plane S.

[0075] It will be appreciated that second position A21 can be considered the projection position of light from projection screen 10' in the related art. As shown in Figure 5, first position A11 is closer to the center of projection screen 10 than second position A21. Thus, when viewer 30 views from a position corresponding to the center of projection screen 10, the brightness of the projected image near the center of projection screen 10 is relatively uniform, and projection screen 10 exhibits good uniformity. Furthermore, light from first position A1' and second position A2' on the central axis L1 of projection screen 10 can be respectively reflected to the center of target plane S.

[0076] In some embodiments, as shown in FIG3 , a first distance D1 between the center O1 of the plurality of Fresnel microstructures 121 and the projection screen 10 is positively correlated with a second distance D2 between the orthographic projection O2 of the light outlet 23 on the plane where the projection screen 10 is located and the projection screen 10, so that the orthographic projection O2 of the light outlet 23 on the plane where the projection screen 10 is located can be located on the side of the center O1 of the plurality of Fresnel microstructures 121 away from the projection screen 10. When the second distance D2 increases, the first distance D1 increases, and when the second distance D2 decreases, the first distance D1 decreases. The second distance D2 between the orthographic projection O2 of the light outlet 23 on the plane where the projection screen 10 is located and the projection screen 10 is related to the off-axis of the projection device 20. The second distance D2 can be calculated by formula (1): D2 = W × (OFFSET-1) / 2; (1)

[0077] W is the width of the projection screen 10 .

[0078] In some embodiments, the first distance D1 can be less than two-thirds of the second distance D2 (D1 < 2D2 / 3). In other words, D1 < W × (OFFSET-1) / 3. Thus, when using the projection system 100, after determining the positions of the projection device 20 and the projection screen 10, the first distance D1 is less than the second distance D2 (D1 < D2), so that the center O1 of the multiple Fresnel microstructures 121 can be located on the side of the orthographic projection O2 of the light outlet 23 on the plane of the projection screen 10 that is closer to the projection screen 10.

[0079] Compared to a case where the first distance D1 is greater than two-thirds of the second distance D2 and less than the second distance D2 (2D2 / 3 < D1 < D2), when the first distance D1 is less than two-thirds of the second distance D2 (D1 < 2D2 / 3), the radius of the multiple Fresnel microstructures 121 is smaller. In other words, the radius of the Fresnel microstructures 121 corresponding to the same position on the projection screen 10 is relatively small. Thus, when the incident light 21 strikes that same position, the Fresnel lens layer 12 achieves a better light converging effect, resulting in a more uniform projection screen 10.

[0080] Of course, in some embodiments, the first distance D1 may be greater than two-thirds of the second distance D2 and less than the second distance D2 (2D2 / 3<D1<D2). In this case, the center O1 of the multiple Fresnel microstructures 121 may also be located on the side of the orthographic projection O2 of the light outlet 23 on the plane of the projection screen 10 that is closer to the projection screen 10.

[0081] In some embodiments, the first distance D1 may also be greater than two-fifths of the second distance D2 ( D1 > W(OFFSET-1) / 5) and smaller than the second distance D2 ( 2D2 / 5 < D1 < D2 ).

[0082] FIG. 6 is a brightness comparison diagram of a projected image according to some embodiments.

[0083] When first distance D1 is less than two-fifths of second distance D2 (D1 < 2D2 / 5), light tends to converge excessively toward the center of projection screen 10. In this case, as shown in FIG6 , when viewer 30 views projection screen 10 from the side, uneven brightness tends to appear on both sides of projection screen 10. Therefore, when first distance D1 is greater than two-fifths of second distance D2 but less than second distance D2 (2D2 / 5 < D1 < D2), projection screen 10 exhibits better uniformity and produces a better projected image.

[0084] In some embodiments, the eccentricity of the projection device 20 can be 129%, 133%, or 145%. Furthermore, different eccentricity distances (first distances D1) can be set for projection screens 10 of different sizes, so that when projection screens 10 of different sizes are used with projection devices 20 of different eccentricities, the projection screen 10 has better uniformity.

[0085] In some embodiments, when the diagonal length of the projection screen 10 is 80 inches (first length) and the ratio of the length of the projection screen 10 to the width of the projection screen 10 is 16:9 (first ratio), the first distance D1 is any value within the third range (e.g., D1 < 143 mm).

[0086] For a projection device 20 with an off-axis value of 129% and an 80-inch projection screen 10, the second distance D2 can be determined to be 143 mm according to formula (1). Because the first distance D1 is less than 143 mm, the center O1 of the multiple Fresnel microstructures 121 can be located on the side of the orthographic projection O2 of the light outlet 23 on the plane of the projection screen 10 that is close to the projection screen 10, resulting in better uniformity of the projection screen 10.

[0087] It can be understood that when the first distance D1 is less than 143 mm, it can be determined according to formula (1) that for the projection device 20 with an off-axis of 133% or 145% and an 80-inch projection screen, the center O1 of the multiple Fresnel microstructures 121 is also located on the side of the orthographic projection O2 of the light outlet 23 on the plane where the projection screen 10 is located, close to the projection screen 10.

[0088] Therefore, when the projection screen 10 is 80 inches and the first distance D1 is less than 143 mm, the uniformity of the projection screen 10 can be better for different types of projection devices 20, thereby improving the projection effect.

[0089] In some embodiments, when the diagonal length of the projection screen 10 is 100 inches (the second length) and the ratio of the length of the projection screen 10 to the width of the projection screen 10 is 16:9 (the second ratio), the first distance D1 is any value within the fourth range (e.g., D1 < 180 mm).

[0090] For a projection device 20 with an off-axis angle of 129% and a 100-inch projection screen 10, the second distance D2 can be determined to be 180 mm according to formula (1). Because the first distance D1 is less than 180 mm, the center O1 of the multiple Fresnel microstructures 121 can be located on the side of the orthographic projection O2 of the light outlet 23 on the plane of the projection screen 10 that is close to the projection screen 10, resulting in better uniformity of the projection screen 10.

[0091] It can be understood that, for a projection device 20 with an off-axis of 133% or 145% and a 100-inch projection screen 10, it can be determined according to formula (1) that the center O1 of the multiple Fresnel microstructures 121 is also located on the side of the orthographic projection O2 of the light outlet 23 on the plane where the projection screen 10 is located, close to the projection screen 10.

[0092] Therefore, when the projection screen 10 is 100 inches and the first distance D1 is less than 180 mm, the uniformity of the projection screen 10 can be better for different types of projection devices 20, thereby improving the projection effect.

[0093] In some embodiments, when the diagonal length of the projection screen 10 is 120 inches (the third length) and the ratio of the length of the projection screen 10 to the width of the projection screen 10 is 16:9 (the third ratio), the first distance D1 is any value within the fifth range (e.g., D1 < 216 mm).

[0094] For a projection device 20 with an off-axis value of 129% and a 120-inch projection screen 10, the second distance D2 can be determined to be 216 mm according to formula (1). Because the first distance D1 is less than 216 mm, the center O1 of the multiple Fresnel microstructures 121 can be located on the side of the orthographic projection O2 of the light outlet 23 on the plane of the projection screen 10 that is close to the projection screen 10, resulting in better uniformity of the projection screen 10.

[0095] It can be understood that, for a projection device 20 with an off-axis of 133% or 145% and a 120-inch projection screen 10, the center O1 of the multiple Fresnel microstructures 121 is also located on the side close to the projection screen 10 of the orthographic projection O2 of the light outlet 23 on the plane where the projection screen 10 is located.

[0096] Therefore, when the projection screen 10 is 120 inches and the first distance D1 is less than 216 mm, the uniformity of the projection screen 10 can be better for different types of projection devices 20, thereby improving the projection effect.

[0097] Since a too small first distance D1 can easily lead to inconsistent brightness of the projected image on both sides of the projection screen 10, in some embodiments, the first distance D1 can be greater than a preset value. For example, the preset value is 40 mm. For projection screens 10 of different sizes (e.g., 80 inches, 100 inches, or 120 inches), when the first distance D1 is greater than 40 mm, the brightness of the projected image on both sides can be better maintained consistent, and the projection effect of the projection device 20 is better.

[0098] Of course, the preset value may also be other values. For example, the preset value may be 45 mm or 50 mm. The preset value may be determined based on the effect of the projection image corresponding to the parameters of the projection device 20 (e.g., eccentricity) and the parameters of the projection screen 10 (e.g., size).

[0099] In addition, different first distances D1 may be designed for projection devices 20 with different off-axis values ​​according to the relationship between the second distance D2 and the first distance D1.

[0100] For example, if the first distance D1 is greater than two-fifths of the second distance D2 and less than two-thirds of the second distance D2 (2D2 / 5<D1<2D2 / 3), the size of the projection screen 10 is 80 inches, and the ratio of the length of the projection screen 10 to the width of the projection screen 10 is 16:9, if the off-axis of the projection device 20 is 145%, the first distance D1 can be greater than 89.1 mm and less than 148 mm (89.1 mm<D1<148 mm), thereby achieving better uniformity of the projection screen 10. In the above case, if the off-axis of the projection device 20 is 133%, the first distance D1 can be greater than 65 mm and less than 108 mm (65 mm<D1<108 mm). Similarly, the value range of the first distance D1 for projection screens 10 of different sizes can be determined based on other off-axis values ​​of the projection device 20, which will not be further described here.

[0101] To improve the gain of the projection screen 10 , in some embodiments of the present disclosure, a first angle α formed between the first surface 1211 and the surface of the surface layer 11 close to the Fresnel lens layer 12 is determined according to the radius of the Fresnel lens layer 12 .

[0102] In some embodiments, as shown in FIG3 , the Fresnel microstructure 121 includes a first surface 1211 and a second surface 1212. The first surface 1211 and the second surface 1212 are connected to each other. The first surface 1211 is tilted, and a fifth distance D5 between the end of the first surface 1211 closer to the second surface 1212 and the surface layer 11 is greater than a sixth distance D6 between the end of the first surface 1211 farther from the second surface 1212 and the surface layer 11. For example, as shown in FIG3 , the first surface 1211 is tilted toward the rear and downward. The first angle α formed between the first surface 1211 and the surface of the surface layer 11 closer to the Fresnel lens layer 12 is the sum of the first target coefficient θ and the second angle A (α=θ+A).

[0103] Here, the second angle A is any value within the first range. For example, the second angle A is greater than -5° and less than 5° (-5°<A<5°), for example, the second angle A is -4°, 0° or 4°. There is a preset relationship between the first target coefficient θ and the radius r of the Fresnel microstructure 121. For example, the preset relationship is as follows: Formula (2) (first target formula). θ=2.2777764775843E -15 r 5 -1.6393352729939E -11 r 4 +4.7433765352602E -8 r 3 - 7.1110397598114E -5 r 2+6.3971788444051E -2 r-5.6385768409072 (2)

[0104] Here, r is the radius of the Fresnel microstructure 121. Thus, the first target coefficient θ can be determined based on the radius of the Fresnel microstructure 121, and the first angle α can be determined based on the first target coefficient θ and the second angle A. By setting this first angle α, light emitted by the projection device 20, after passing through the Fresnel microstructure 121, is more likely to converge toward the center of the projection screen 10, thereby improving the light convergence effect, increasing the gain of the projection screen 10, and enhancing the projection effect of the projection screen 10.

[0105] It should be noted that, since the width of the Fresnel microstructure 121 is relatively narrow, the distance from any point on the Fresnel microstructure 121 to the circle center O1 can be used as the radius r of the Fresnel microstructure 121 .

[0106] In some embodiments, the refractive index of the surface layer 11 can be the same as that of the Fresnel lens layer 12. This prevents light from being refracted when it passes from the surface layer 11 to the Fresnel lens layer 12. This prevents light from being refracted when passing through the surface layer 11 and the Fresnel lens layer 12, causing deflection and affecting the light's exit angle. Thus, when the angle corresponding to the Fresnel microstructures 121 is the first angle α, light can converge toward the center of the projection screen 10, resulting in higher gain for the projection screen 10.

[0107] Of course, in some embodiments, the refractive index of the surface layer 11 may differ from that of the Fresnel lens layer 12. In this case, light will refract when passing through the boundary between the surface layer 11 and the Fresnel lens layer 12 due to the difference in refractive index. In this case, a correction factor can be set to correct the first angle α to eliminate the effect of the difference in refractive index between the surface layer 11 and the Fresnel lens layer 12 on the exit angle of the outgoing light.

[0108] It should be noted that the refractive index difference between the material making up the surface layer 11 and the material making up the Fresnel lens layer 12 is generally small. When light passes through the boundary between the surface layer 11 and the Fresnel lens layer 12, the angle of refraction is small, which has a minimal impact on the gain effect of the projection screen 10. Therefore, when the refractive index of the surface layer 11 and the refractive index of the Fresnel lens layer 12 are different, the first angle α does not need to be corrected. In this case, the projection screen 10 still has a high gain.

[0109] In some embodiments, the refractive index of the Fresnel lens layer 12 is any value within a second range. The second range is 1.4 to 1.65. For example, the refractive index of the Fresnel lens layer 12 is 1.4, 1.5, or 1.65. In this case, the first angle α determined according to formula (2) can achieve a better light focusing effect and a higher gain effect.

[0110] In some embodiments, when the refractive index of the Fresnel lens layer 12 is outside the second range (e.g., the refractive index of the Fresnel lens layer 12 is less than 1.4 or the refractive index of the Fresnel lens layer 12 is greater than 1.65), the refractive index of the Fresnel lens layer 12 will affect the effect of converging light at the first angle α. Therefore, in order to make the light emitted by the projection device 20 converge as much as possible toward the center of the Fresnel projection screen 1, a second correction coefficient can be set to correct the first angle α. In this case, the first angle α can be determined by formula (3) (fourth target formula). α=m×(θ+A); (3)

[0111] m is the second correction coefficient. Thus, when the refractive index of the Fresnel lens layer 12 is less than 1.4 or the refractive index of the Fresnel lens layer 12 is greater than 1.65, the first angle α is corrected by the second correction coefficient m, so that the light projected by the projection device 20 can converge toward the center of the projection screen 10, thereby increasing the gain of the projection screen 10.

[0112] For example, the second correction coefficient m is a constant. Different second correction coefficients m can be selected for different refractive indices of the Fresnel lens layer 12. For example, when the refractive index of the Fresnel lens layer 12 is greater than 1.65, the value of the second correction coefficient m is greater than or equal to 0.8 and less than 1 (0.8≤m<1). For example, the second correction coefficient m is 0.8, 0.85, or 0.9. When the refractive index of the Fresnel lens layer 12 is less than 1.4, the second correction coefficient m is greater than 1 and less than or equal to 1.2 (1<m≤1.2). For example, the second correction coefficient m is 1.1, 1.15, or 1.2. The value of the second correction coefficient m can be determined based on the effect of the projected image to correct the first angle α.

[0113] Of course, in some embodiments, when the refractive index of the Fresnel lens layer 12 is slightly less than 1.4 or slightly greater than 1.65, the first angle α may not be corrected. In this case, the second correction coefficient m is 1.

[0114] In some embodiments, the second correction coefficient m can be negatively correlated with the refractive index of the Fresnel lens layer 12. As shown in FIG3 , when the refractive index of the Fresnel lens layer 12 is greater, the refraction angle of the light projected by the projection device 20 when entering the interior of the projection screen 10 is greater. Taking the light shown in FIG3 as an example, in order to make the light horizontal after passing through the Fresnel microstructure 121, the greater the refraction angle of the light when entering the interior of the projection screen 10, the smaller the angle of the third angle β needs to be. According to the principle of light reflection, the first angle α of the Fresnel microstructure 121 is half of the third angle β (α=β / 2). Therefore, the greater the refractive index of the light, the smaller the first angle α is required, so that the light converges toward the center of the projection screen 10, thereby improving the gain effect.

[0115] Figure 7 is a structural diagram of another projection screen according to some embodiments. Figure 8 is a structural diagram of a surface layer according to some embodiments.

[0116] In some embodiments, as shown in Figures 7 and 8 , the surface of the surface layer 11 facing away from the Fresnel lens layer 12 has a plurality of protrusions 111. Providing these protrusions 111 on this surface can increase the viewing angle of the projection screen 10 and reduce the reflectivity of the surface. For example, the surface of the surface layer 11 facing away from the Fresnel lens layer 12 can be formed by sandblasting, which is simple, convenient, and easy to implement. It should be noted that, as shown in Figure 8 , the shapes of the multiple protrusions 111 can be identical, or, as shown in Figure 7 , the shapes of the multiple protrusions 111 can be different.

[0117] With the above arrangement, the light reflectivity of the surface layer 11 is low. Thus, when the light emitted by the projection device 20 reaches the surface layer 11, more light can pass through the surface layer 11 and enter the interior of the projection screen 10, so that the light emitted by the projection device 20 is less likely to form a clear image in other places (such as the ceiling).

[0118] FIG. 9 is a diagram illustrating the optical path of light passing through a surface layer according to some embodiments.

[0119] As shown in FIG9 , when light is incident from both sides of the surface layer 11 , the light passes through the protrusions 111 , which affect the path of the light and cause the light to be deflected.

[0120] For example, as shown in Figure 9, taking the incident angle B of the incident light on both sides of the surface layer 11 as 60° as an example, after a portion of the light below the surface layer 11 passes through the protrusion 111 and emerges from above the surface layer 11, the surface layer 11 contracts this portion of the light, so that the exit angle γ of this portion of the light is smaller. For example, as shown in Figure 9, the exit angle of this portion of the light is less than 60°. After a portion of the light above the surface layer 11 passes through the protrusion 111 and emerges from below the surface layer 11, the surface layer 11 amplifies this portion of the light, so that the exit angle γ of this portion of the light is larger. For example, as shown in Figure 9, the exit angle of this portion of the light is greater than 60°. It should be noted that, among the portion of the light below or above the surface layer 11, at least part of the light will undergo total internal reflection when passing through the surface layer 11.

[0121] FIG. 10 is a diagram illustrating light paths of a projection screen according to some embodiments.

[0122] Since the protrusions 111 affect the light, the surface of the surface layer 11 on the side away from the Fresnel lens layer 12 has multiple protrusions 111, and the first angle α of the first surface 1211 is the sum of the first target coefficient θ and the second angle A (α=(θ+A)). As shown in Figure 10, after the light passes through the protrusions 111 and the Fresnel microstructure 121, it is emitted upward and deviates from the center position, affecting the gain of the projection screen 10.

[0123] Therefore, in some embodiments, when the surface layer 11 has a plurality of protrusions 111 on the side away from the Fresnel lens layer 12, a first correction coefficient k can be set to correct the first angle α. In this case, the first angle α can be determined by formula (4) (second target formula). α = k × (θ + A) (4)

[0124] k is a first correction coefficient, k≠0 and k≠1. For example, the first correction coefficient k is greater than or equal to 0.8 and less than or equal to 1.3 (0.8≤k≤1.3). For example, the first correction coefficient k is 0.8, 1.1, or 1.3.

[0125] FIG. 11 is another light path diagram of light passing through a surface layer according to some embodiments.

[0126] For example, when the first angle α is the product k(θ+A) of the sum of the first correction coefficient k, the first target coefficient θ, and the second angle A, as shown in FIG11 , after passing through the Fresnel microstructure 121, the light can be emitted toward the center of the projection screen 10, eliminating the influence of the protrusion 111 on the light path and improving the gain of the projection screen 10.

[0127] It should be noted that, for the convenience of observation, FIG9 and FIG10 only show the light diagrams of part of the protrusion 111 and the Fresnel microstructure 121, and omit other structures.

[0128] Fig. 12 is another schematic diagram of light projection of a projection screen according to some embodiments. Fig. 12 is illustrated by taking the surface layer 11 having protrusions 111 as an example.

[0129] As shown in Figure 12, light emitted by projection device 20 is reflected by projection screen 10 and then emitted to target plane S. The dashed line with an arrow represents the light path before the first angle α is corrected. Before the first angle α is corrected, the light will deviate due to the action of protrusion 111 and will not converge toward the center of projection screen 10, thereby reducing the gain of projection screen 10.

[0130] The solid line with arrows represents the light path after the angle α is corrected. After the first angle α is corrected, the light can converge toward the center of the projection screen 10, thereby improving the gain of the projection screen 10.

[0131] FIG. 13 is a schematic diagram illustrating light passing through a surface layer according to some embodiments.

[0132] In some embodiments, when the surface of the surface layer 11 away from the Fresnel lens layer 12 is smooth, the first angle α can be the sum of the first target coefficient θ and the second angle A (α = (θ + A)). In this case, as shown in FIG13 , after passing through the Fresnel lens layer 12, the light can be emitted toward the center of the projection screen 10, and the gain of the projection screen 10 is relatively high.

[0133] Because different radii of the Fresnel microstructures 121 correspond to different first angles α, in some embodiments, when the radii of the multiple Fresnel microstructures 121 are different, the first correction coefficient k corresponding to each of the multiple Fresnel microstructures 121 can be different. Thus, different first correction coefficients k can be used for Fresnel microstructures 121 with different radii. This allows light emitted by the projection device 20 to converge toward the center after passing through each Fresnel microstructure 121, thereby increasing the gain of the projection screen 10.

[0134] Of course, in other embodiments, the first correction coefficient k corresponding to multiple Fresnel microstructures 121 may also be the same. The first correction coefficient k can be set according to actual conditions. For example, when setting the first correction coefficient k, different first correction coefficients k can be selected, and the gain effect of the projection screen 10 corresponding to each first correction coefficient k can be determined, and then the first correction coefficient k that can achieve the highest gain of the projection screen 10 can be selected.

[0135] In some embodiments, as shown in FIG11 , the protrusion 111 is hemispherical. In the case where the protrusion 111 is hemispherical, the first correction coefficient k can be determined by formula (5). k=k0+b (5)

[0136] There is a preset relationship between the second target coefficient k0 and the sequence number X of the plurality of Fresnel microstructures 121. For example, the preset relationship is as follows: formula (6) (third target formula): k0 = 1.6089315478386E -21 X 5 –8.4586327227823E -17 X 4 +1.6900833055087E –12 X 3 – 1.6087126401172E -8 X 2 +7.2849973133300E -5 X+1.0256456238937; (6)

[0137] Here, k0 is the second target coefficient, and b is the correction constant. For example, the correction constant b is greater than or equal to -0.3 and less than or equal to 0.3 (-0.3≤b≤0.3). For example, the correction constant b is -0.3, 0, or 0.3.

[0138] Here, X is a positive integer and represents the sequence number of the plurality of Fresnel microstructures 121. It should be noted that the sequence number of the Fresnel microstructures 121 increases as one moves away from the center O1 of the circle of the plurality of Fresnel microstructures 121. The closer to the center, the smaller the radius of the Fresnel microstructure 121, the smaller the sequence number. The sequence number of the Fresnel microstructure 121 with the smallest radius is 1, meaning that the minimum value of X is 1.

[0139] When the protrusion 111 is hemispherical, the first correction coefficient k corresponding to each of the multiple Fresnel microstructures 121 can be determined using formula (4). Thus, as shown in FIG7 , light at the center of the projection screen 10 can be emitted toward the center of the projection screen 10 after passing through the Fresnel microstructure 121, resulting in a higher gain for the projection screen 10.

[0140] For example, as shown in FIG10 , when the refractive index of the Fresnel lens layer 12 and the refractive index of the protrusion 111 are both 1.56, the first angle α of the Fresnel microstructure 121 at the center of the projection screen 10 is 16.5° before correction, and light enters at an angle of incidence of 58.5° and exits in a direction 12° away from the center. As shown in FIG13 , after correction according to formulas (4) and (5), the first angle α is 19.5°, and the light exits toward the center.

[0141] FIG. 14 is a structural diagram of a surface layer according to some embodiments.

[0142] In some embodiments, as shown in FIG14 , the surface layer 11 includes first diffusion particles 401. The first diffusion particles 401 are distributed on a side of the surface layer 11 (e.g., the front side) away from the Fresnel lens layer 12. This increases the viewing angle of the projection screen 10 and increases the roughness of the surface, allowing more light to pass through the surface and preventing clear images from forming elsewhere.

[0143] It should be noted that, when the surface layer 11 includes the first diffusion particles 401, the first angle α can also be corrected according to formulas (4), (5), and (6), or a fixed first correction coefficient k can be selected for correction. The first correction coefficient k can be set according to actual conditions.

[0144] In some embodiments, the diffusion particles 40 may be made of polymethyl methacrylate (PMMA).

[0145] FIG. 15 is a structural diagram of a protrusion according to some embodiments.

[0146] In some embodiments, as shown in FIG15 , the surface of the protrusion 111 can be a frosted surface. By frosting the surface of the protrusion 111, the surface roughness can be further increased, thereby further reducing the reflectivity of light on the surface, improving the transmittance of light, and improving the efficiency of utilizing the light emitted by the projection device 20, thereby preventing the formation of a clear image elsewhere due to light reflection. In this case, the first angle α can be corrected according to formulas (4), (5), and (6), or a fixed first correction coefficient k value can be selected for correction.

[0147] It should be noted that when the first distance D1 between the center O1 of the multiple Fresnel microstructures 121 and the projection screen 10 is small, the radius of the multiple Fresnel microstructures 121 is small, and the light converging ability is strong. In this way, even when the surface of the surface layer 11 away from the Fresnel lens layer 12 is uneven, the projection screen 10 can maintain good uniformity.

[0148] In some embodiments, as shown in FIG3 , projection screen 10 further includes a diffusion layer 14. Diffusion layer 14 is located between surface layer 11 and Fresnel lens layer 12. Diffusion layer 14 includes second diffusion particles 402. Incident light 21 diffuses in all directions when passing through diffusion layer 14, thereby increasing the viewing angle of projection screen 10.

[0149] The refractive index of the diffusion layer 14 and the surface layer 11 can be the same. This allows light projected by the projection device 20 to avoid deflection when it enters the diffusion layer 14 from the surface layer 11. This allows the light to exit in its intended direction after passing through the Fresnel lens layer 12, thereby improving the gain of the projection screen 10. Of course, the refractive index of the diffusion layer 14 can also differ from that of the Fresnel lens layer 12. Since the difference in refractive index between the materials making up the two is relatively small, when the first angle α is the sum of the first target coefficient θ and the second angle A (α = (θ + A)), the gain of the projection screen 10 is minimal.

[0150] Furthermore, the coherence between the diffused light rays is weaker, reducing the degree of light interference on the surface of projection screen 10 and, in turn, lessening the severity of speckle on the surface of projection screen 10. It should be noted that although the light rays are diffused, the degree of diffusion caused by the diffuser particles 40 is minimal, and the light rays still converge toward the center of projection screen 10, thus having a minimal impact on the gain effect of projection screen 10. In this case, there is no need to modify the first angle α due to the provision of the diffuser layer 14.

[0151] In some embodiments, as shown in FIG3 , the projection screen 10 further includes a tinting layer 15. The tinting layer 15 can be located between the surface layer 11 and the Fresnel lens layer 12. For example, as shown in FIG3 , the tinting layer 15 is located between the surface layer 11 and the diffusion layer 14. The tinting layer 15 includes a dark dye 16. The dark dye 16 is configured to enhance the contrast of the projection screen 10. Thus, when ambient light passes through the tinting layer 15, it is absorbed by the dark dye 16, thereby enhancing the projection screen 10's ability to resist ambient light. This allows the projection screen 10 to maintain good contrast even in brightly lit environments, improving the display quality of the projected image.

[0152] Of course, the dark dye 16 can also be disposed at other locations on the projection screen 10. For example, as shown in FIG7 , the dark dye 16 is disposed within the reflective layer 13. When ambient light passes through the reflective layer 13, the ambient light is absorbed by the dark dye 16 within the reflective layer 13.

[0153] In some embodiments, the colored layer 15 may have the same refractive index as the surface layer 11. In this way, when light emitted by the projection device 20 passes between the surface layer 11 and the colored layer 15, the light will not be refracted, thereby reducing the effect of light refraction on the emission angle, allowing the light to converge toward the center.

[0154] When projection screen 10 includes a diffusion layer 14 and a coloring layer 15, the refractive index of the coloring layer 15 can be the same as or different from the refractive indices of the surface layer 11, the Fresnel lens layer 12, and the diffusion layer 14. When the refractive index of the coloring layer 15 differs from the refractive indices of the surface layer 11 and the diffusion layer 14, as shown in FIG13 , light is deflected when it enters the coloring layer 15 from the surface layer 11. Because the refractive indices of the surface layer 11 and the diffusion layer 14 can be the same, when the coloring layer 15 enters the diffusion layer 14, the direction of the light is the same as when it entered the coloring layer 15. For example, the refractive indices of the surface layer 11 and the diffusion layer 14 can be 1.65, the refractive index of the coloring layer 15 can be 1.48, and the refractive index of the Fresnel lens layer 12 can be 1.56.

[0155] It should be noted that the materials used for each layer of projection screen 10 can be determined based on actual circumstances. Taking the projection screen 10 shown in Figure 3 as an example, the Fresnel lens layer 12, diffusion layer 14, and coloring layer 15 can each be made of ultraviolet (UV)-curable adhesive. UV-curable adhesive, also known as UV adhesive, is elastic and thus allows the Fresnel lens layer 12 to be rolled.

[0156] In this case, the diffusion layer 14 can be used as a substrate for manufacturing the Fresnel lens layer 12. The following description will be made by taking the Fresnel lens layer 12 formed by curing UV adhesive as an example.

[0157] When manufacturing the Fresnel lens layer 12, UV glue is applied to the surface of the diffusion layer 14. A mold is then used to emboss the Fresnel lens layer 12 to form the Fresnel lens layer 12. The UV glue is then cured using a UV light source, and the layer is demolded to complete the manufacturing of the Fresnel lens layer 12. Of course, in other embodiments, the Fresnel lens layer 12 may also be made of other materials (e.g., thermosetting glue).

[0158] Similarly, the coloring layer 15 can also be fabricated using the diffusion layer 14 as a base. To fabricate the coloring layer 15, a dark dye 16 is added to a UV adhesive. The UV adhesive with the dark dye 16 is then applied to the surface of the diffusion layer 14 facing away from the Fresnel lens layer 12, and then cured using an ultraviolet lamp.

[0159] In some embodiments, as shown in FIG7 , projection screen 10 further includes a substrate layer 17. Substrate layer 17 is positioned between surface layer 11 and reflective layer 13 and serves as the base for fabricating projection screen 10. For example, in the projection screen 10 shown in FIG7 , substrate layer 17 serves as the base for fabricating surface layer 11 and Fresnel lens layer 12. When fabricating surface layer 11, UV adhesive is applied to the surface of substrate layer 17 facing away from Fresnel lens layer 12, and then cured using an ultraviolet lamp to complete fabrication of surface layer 11.

[0160] In some embodiments, the substrate layer 17 can be made of different materials. For example, the substrate layer 17 is made of polyethylene terephthalate (PET). PET is flexible, allowing the substrate layer 17 to be curled. Of course, the substrate layer 17 can also be made of other flexible materials. For example, the substrate layer 17 can be made of thermoplastic polyurethane (TPU). TPU is elastic and allows the substrate layer 17 to be curled. Alternatively, the substrate layer 17 can also be made of a flexible styrenic block copolymer (SBC).

[0161] TPU materials offer a wide range of hardness, maintaining excellent elasticity and wear resistance even with increasing hardness. They also exhibit excellent oil resistance, aging resistance, and abrasion resistance. SBC materials are flexible and possess excellent mechanical properties, are waterproof, and exhibit strong tensile strength, tear strength, and ball burst strength. SBC materials also exhibit excellent resistance to oxidation, water, weathering, chemicals, and corrosion. The SBC substrate has a rough surface and a three-dimensional network structure, which provides excellent bonding strength with a variety of adhesives and can be blended with other materials to improve the material's performance and strength.

[0162] In some embodiments, substrate layer 17 can be made of polyurethane (PU). The PU material's flexibility allows projection screen 10 to be rolled. PU also adapts to substrates with varying thermal expansion coefficients, forming a soft-hard transition layer with the substrate, resulting in strong adhesion. Consequently, the PU material integrates better with the other layered structures of projection screen 10 and provides excellent cushioning and shock absorption capabilities.

[0163] In some embodiments, the reflective material in the reflective layer 13 may also be a metal (e.g., aluminum or silver), or a combination of metals (e.g., a combination of silver and aluminum) to achieve the reflective function of the reflective layer. In addition, materials of different shapes can be used as the material of the reflective layer 13 to reflect light.

[0164] Hereinafter, the reflective layer 13 of some embodiments of the present disclosure will be exemplarily described by taking aluminum as an example.

[0165] FIG. 16 is a structural diagram of a reflective layer according to some embodiments.

[0166] In some embodiments, as shown in FIG16 , powdered aluminum is applied to the Fresnel lens layer 12 by spray printing or vapor deposition. Because the powdered aluminum is relatively fine and has little directionality, most of the light emitted by the projection device 20 can be directionally reflected out of the projection screen 10 based on the arrangement of the multiple Fresnel microstructures 121, avoiding scattered light reflections and thereby increasing the gain of the projection screen 10.

[0167] When aluminum particles are selected as the reflective material, the diameter of the aluminum particles can be any value within a first preset range. For example, the first preset range is 5μm to 20μm. For example, the diameter of the aluminum particles is 5μm, 10μm, or 20μm, etc. Within the first preset range, since the diameter of the aluminum particles is relatively small, after the reflective layer 13 is formed, the aluminum particles will form a dense reflective surface. When light is irradiated on this reflective surface, the light can be reflected as much as possible, thereby avoiding waste of light energy. In addition, when aluminum particles are selected as the reflective material, the reflective layer 13 can be thinner, thereby saving the consumption of aluminum material and saving production costs.

[0168] FIG. 17 is a structural diagram of another reflective layer according to some embodiments.

[0169] In some embodiments, as shown in FIG17 , since the flaky aluminum powder has a large diameter-to-thickness ratio and a strong aluminum bonding ability, making it less likely to fall off, the flaky aluminum powder can also be spray-coated onto the Fresnel lens layer 12 using a spray printing method. The diameter-to-thickness ratio of the flaky aluminum powder can be any value within a second preset range. For example, the second preset range is (40:1) to (100:1). For example, the diameter-to-thickness ratio is the ratio of the aluminum powder's diameter to its thickness.

[0170] Typically, the Fresnel lens layer 12 is produced by mold transfer. For example, a high-precision diamond machining machine is used to create a flat Fresnel mold. This Fresnel mold is then used for embossing to produce the Fresnel lens layer. However, this mold production method is susceptible to limitations in the machine tool's processing capacity. Typically, the maximum processing diameter is less than or equal to 3.4 μm, which only meets the production requirements for Fresnel molds 100 inches or smaller.

[0171] In some embodiments, as shown in Figure 3, the cross-sectional shape of the Fresnel lens layer 12 can be sawtooth-shaped. Accordingly, when producing the mold, the machining machine typically requires rotary structural processing. For Fresnel lens layers 12 sized 100 inches or larger, the machining radius R of the machine tool must be at least 1.6 meters.

[0172] Currently, there are few machines capable of producing molds for Fresnel lens layers 12 larger than 100 inches, and the cost of manufacturing is high. Furthermore, as the size of the machine tools increases, the machining accuracy and stability of the structure decrease accordingly. Since the design size of the Fresnel structure is only several hundred microns, the machining effect is relatively poor.

[0173] In order to solve the above problems, some embodiments of the present disclosure provide a mold 500 .

[0174] Figure 18 is a structural diagram of a mold according to some embodiments. Figure 19 is a cross-sectional view of the mold shown in Figure 18.

[0175] As shown in Figures 18 and 19, the mold 500 includes a first sub-mold 51 and a second sub-mold 52. The first sub-mold 51 includes a first sub-mold body 511 and a plurality of first band structures 512. The first sub-mold body 511 has a first structural surface 5111, and the plurality of first band structures 512 are sequentially arranged (e.g., nested) on the first structural surface 5111. As shown in Figure 18, one of two adjacent first band structures 512 is located outside or inside the other first band structure 512.

[0176] The second sub-mold 52 includes a second sub-mold main body 521 and a plurality of second belt structures 522. The second sub-mold main body 521 is connected to the first sub-mold main body 511. The second sub-mold main body 521 has a second structural surface 5211, which is spliced ​​with the first structural surface 5111 to form a larger plane.

[0177] Multiple second ribbon structures 522 are disposed on the second structural surface 5211. As shown in FIG18 , one of two adjacent second ribbon structures 522 is located outside or inside the other second ribbon structure 522. The multiple second ribbon structures 522 are disposed outside the multiple first ribbon structures 512. The multiple first ribbon structures 512 and the multiple second ribbon structures 522 can be used to form a Fresnel microstructure 121.

[0178] In some embodiments of the present disclosure, mold 500 is formed by splicing a first sub-mold 51 and a second sub-mold 52. Thus, when manufacturing mold 500, the first sub-mold 51 and the second sub-mold 52 can be separately manufactured. Subsequently, the first sub-mold 51 and the second sub-mold 52 are connected so that the first structural surface 5111 and the second structural surface 5211 are spliced ​​together. In this way, the plurality of sequentially arranged first band structures 512 and the plurality of second band structures 522 sequentially arranged around the plurality of first band structures 512 can be used to manufacture larger-sized Fresnel microstructures, allowing mold 500 to produce larger-sized Fresnel lens layers 12, thereby enabling the production of larger-sized projection screens 10.

[0179] Furthermore, because the plurality of second band structures 522 are disposed around the plurality of first band structures 512, the first band structures 512 and the second band structures 522 are each complete structures, and there is no splicing between the plurality of first band structures 512 or the plurality of second band structures 522. Thus, the seams of the mold 500 have little effect on the Fresnel microstructures 121, and the Fresnel lens manufactured using the mold 500 has better production quality, thereby enhancing the projection quality of the projection screen 10 incorporating the Fresnel lens.

[0180] Because the Fresnel microstructure is composed of multiple concentric annular prisms located on the same plane, in some embodiments, as shown in FIG19 , the first band structure 512 and the second band structure 522 can each be a prismatic lens structure with a triangular cross-section. The magnitude of the fourth angle C formed by the prismatic lens structure can be set according to actual needs. For example, the fourth angle C can be any value between 5° and 85°. For example, the fourth angle C can be 5°, 50°, or 85°.

[0181] In some embodiments, as shown in FIG. 18 , the plurality of first belt structures 512 and the plurality of second belt structures 522 are arc-shaped, and the centers of the plurality of first belt structures 512 and the centers of the plurality of second belt structures 522 may coincide with each other.

[0182] In some embodiments, as shown in FIG18 , dashed line 510 indicates the joining location of the first sub-mold 51 and the second sub-mold 52. A first tape structure 512 is also provided at the joining location indicated by dashed line 510, so that the mold 500 formed by joining the first sub-mold 51 and the second sub-mold 52 can produce a well-structured Fresnel microstructure 121. Thus, after the first sub-mold 51 and the second sub-mold 52 are joined, multiple first tape structures 512 and multiple second tape structures 522 can be embossed to form a complete Fresnel microstructure 121.

[0183] In some embodiments, as shown in FIG. 18 , the mold 500 may be rectangular. Thus, when the mold 500 is used to produce a Fresnel lens, it may be directly embossed on a rectangular plane of corresponding size to produce a rectangular Fresnel lens.

[0184] For example, the projection screen 10 is usually rectangular in shape. When manufacturing the Fresnel lens layer of the projection screen 10, the Fresnel lens layer 12 can be directly manufactured on the surface of the diffusion layer 14 using the mold 500, thereby eliminating the need to cut the Fresnel lens layer 12 manufactured by the mold 500, thereby improving the manufacturing efficiency of the projection screen 10.

[0185] Figure 20 is a structural diagram of the first sub-mold shown in Figure 18. Figure 21 is a structural diagram of the second sub-mold shown in Figure 18.

[0186] In some embodiments, when the mold 500 is rectangular, as shown in FIG20 , the first sub-mold body 511 includes a first splicing surface 5112 and a first arcuate surface 5113. The first splicing surface 5112 and the first arcuate surface 5113 are interconnected. As shown in FIG21 , the second sub-mold body 521 includes a second splicing surface 5212 and a second arcuate surface 5213. The second splicing surface 5212 and the second arcuate surface 5213 are interconnected.

[0187] When the first sub-mold 51 and the second sub-mold 52 are spliced ​​together, the first arc surface 5113 and the second arc surface 5213 fit together, and at least part of the first splicing surface 5112 and at least part of the second splicing surface 5212 are flush with each other. As shown in Figure 18, the first sub-mold 51 and the second sub-mold 52 are spliced ​​together to form a rectangular mold 500.

[0188] In this way, the center of the first arc surface 5113 coincides with the center of the first belt structure 512 , and the center of the second arc surface 5213 coincides with the center of the second belt structure 522 .

[0189] It should be noted that the first sub-mold 51 is a three-dimensional structure having a certain thickness. The plurality of first band structures 512 are provided on a surface of one side of the first sub-mold main body 511. The first arc surface 5113 and the first splicing surface 5112 are respectively surfaces of the first sub-mold main body 511 located on the sides of the plurality of first band structures 512. Correspondingly, the second arc surface 5213 and the second splicing surface 5212 are surfaces of the second sub-mold main body 521 located on the sides of the plurality of second band structures 522.

[0190] For example, as shown in Figure 20, the first arc surface 5113 can be semicircular. As shown in Figure 21, the second joining surface 5212 includes two second sub-joining surfaces 5214, with the second arc surface 5213 connected between the two second sub-joining surfaces 5214. In other words, as shown in Figure 21, the second sub-mold 52 is rectangular with a notch on one side, and the notch forms the second arc surface 5213. In this way, the first arc surface 5113 can be inserted into the notch of the second sub-mold 52, thereby forming a rectangular mold 500.

[0191] Here, the center O3 corresponding to the second arc surface 5213 can be located on the central axis L3 of the second sub-mold 52. Thus, as shown in FIG18 , the centers of the plurality of first and second belt structures 512 and 522 of the mold 500 formed after splicing are also located on the central axis L4 of the mold 500.

[0192] Some embodiments of the present disclosure also provide a mold master to reduce wear and tear on the mold 500. The mold master has a Fresnel microstructure 121, which is formed by imprinting the mold 500. For example, the structure of the mold master is the same as the mold 500 shown in Figures 19 to 21. This allows the mold master to be used during the production of the Fresnel lens layer 12, thereby reducing the number of uses of the mold 500, reducing wear and tear on the mold 500, and increasing its service life. The mold master is a complete mold master.

[0193] In addition, since the mold master is formed by embossing the mold 500 , the size of the Fresnel microstructure 121 of the mold master is relatively large, and can be used for embossing to form a large-sized Fresnel lens layer 12 .

[0194] In some embodiments, the mold master can be made of a flexible material. Due to its flexibility, the mold master can be fixed to the cylindrical surface of a cylindrical roller. Consequently, when manufacturing the Fresnel lens layer 12, the cylindrical roller can be rotated to continuously produce the Fresnel lens layer, thereby improving the production efficiency of the Fresnel lens layer 12. Of course, the material of the mold master can also be selected based on actual conditions, and this disclosure is not limited thereto.

[0195] In addition, the mold master can also be made of a non-curlable material. In this case, when manufacturing the Fresnel lens layer 12, the Fresnel lens layer 12 can be formed by directly stamping the surface of the mold master having the Fresnel microstructure 121.

[0196] FIG22 is a flow chart of a method for manufacturing a mold according to some embodiments.

[0197] Some embodiments of the present disclosure further provide a method for manufacturing a mold, which is used to manufacture the mold 500. As shown in FIG22 , the method includes steps 101 to 103.

[0198] In step 101 , a plurality of first belt structures 512 are produced on a first structural surface 5111 of a first sub-mold main body 511 , and are nested in sequence, to obtain a first sub-mold 51 .

[0199] In step 102 , a plurality of second belt structures 522 are produced on the second structural surface 5211 of the second sub-mold main body 521 , and are nested in sequence, to obtain a second sub-mold 52 .

[0200] In step 103 , the first sub-mold 51 and the second sub-mold 52 are spliced ​​together to obtain the mold 500 , and the plurality of second belt structures 522 are positioned around the plurality of first belt structures 512 .

[0201] For example, when manufacturing the first sub-mold 51 and the second sub-mold 52 , the first sub-mold main body 511 and the second sub-mold main body 521 may be placed on a platform respectively for manufacturing.

[0202] The material of the first sub-mold body 511 and the material of the second sub-mold body 521 can be selected according to actual conditions. The first sub-mold body 511 and the second sub-mold body 521 can be made of the same material. For example, the first sub-mold body 511 and the second sub-mold body 521 can be made of glass, PMMA, polycarbonate (PC) or polyethylene terephthalate (PET) or other transparent materials. For example, the first sub-mold body 511 and the second sub-mold body 521 can be made of PET materials respectively. The decomposition temperature of PET material is around 353°C, and the higher temperature can avoid the structural PET material from being damaged during the processing.

[0203] In addition, the thickness of the first sub-mold body 511 and the second sub-mold body 521 can be selected according to actual conditions. For example, the first sub-mold body 511 and the second sub-mold body 521 can be made of PET material with a thickness between 0.3 mm and 0.8 mm. For example, the PET material is 0.3 mm, 0.5 mm, or 0.8 mm.

[0204] The mold 500 produced through steps 101 to 103 can be used to produce extra-large Fresnel lenses. Furthermore, because the plurality of second band structures 522 are positioned around the plurality of first band structures 512, the first band structures 512 and the second band structures 522 are integrally formed. This improves the quality of the Fresnel lenses produced using the mold 500, thereby enhancing the projection quality of the projection screen 10 including the Fresnel lenses.

[0205] It should be noted that the present disclosure does not limit the order of the steps. For example, the order of step 101 and step 102 can be swapped. For example, step 101 can be performed first, and then step 102. Alternatively, step 102 can be performed first, and then step 103.

[0206] FIG. 23 is another flow chart of a method for manufacturing a mold according to some embodiments.

[0207] In some embodiments, as shown in FIG. 23 , step 101 includes step 1011 and step 1012 .

[0208] In step 1011 , a first embossing layer is produced on the first structural surface 5111 of the first sub-mold body 511 .

[0209] For example, the first embossing layer can be made of resin glue. For example, the first embossing layer can be made of heat-curing glue or shadowless curing glue. When making the first embossing layer, heat-curing glue or UV glue can be applied to the first structural surface 5111 to facilitate embossing.

[0210] In step 1012 , the first embossed layer is embossed using a first tapered roller mold to form a plurality of first belt structures 512 .

[0211] FIG. 24 is a structural diagram of a first sub-mold according to some embodiments.

[0212] For example, as shown in FIG. 24 , the first sub-mold 51 can be manufactured by rotating the first tapered roller mold 300 with one end thereof as an axis and imprinting the first imprinting layer 513 .

[0213] 25 is a structural diagram of a first tapered roller mold according to some embodiments.

[0214] As shown in FIG25 , the conical surface of the first tapered roller mold 300 is provided with microstructures 301. The microstructures 301 are configured to emboss a first belt structure 512. When the first tapered roller mold 300 is rotated as shown in FIG21 , a plurality of first belt structures 512 are nested and arranged on the first embossed layer 513 as shown in FIG18 .

[0215] It should be noted that the first sub-mold 51 is relatively small in size. Therefore, in other embodiments, the first sub-mold 51 can also be directly manufactured by machine tools.

[0216] FIG. 26 is another flowchart of a method for manufacturing a mold according to some embodiments.

[0217] In some embodiments, as shown in FIG. 26 , step 102 includes step 1021 and step 1022 .

[0218] In step 1021 , a second embossing layer is produced on the second structural surface 5211 of the second sub-mold body 521 .

[0219] In step 1022 , the second embossed layer is embossed using a second tapered roller mold to form a plurality of second belt structures 522 .

[0220] FIG. 27 is a structural diagram of a second sub-mold according to some embodiments.

[0221] In some embodiments, as shown in FIG. 27 , the second sub-mold 52 can be manufactured by rotating one end of the second tapered roller mold 400 as an axis and stamping the second stamping layer 523 .

[0222] It should be noted that the structure of the second tapered roller mold 400 is similar to that of the first tapered roller mold 300 , and the main difference between the two is that the size of the second tapered roller 400 is larger than that of the first tapered roller 300 .

[0223] FIG28 is another flowchart of a method for manufacturing a mold according to some embodiments.

[0224] In some embodiments, as shown in FIG. 28 , step 103 includes steps 1031 to 1033 .

[0225] In step 1031 , the first sub-mold 51 is cut to obtain a first arc surface 5113 and a first splicing surface 5112 .

[0226] For example, as shown in Figure 24, after being stamped by the first tapered roller mold 300, a circular first sub-mold 51 can be made. At this time, the first sub-mold 51 can be cut along the dotted line shown in Figure 24 to obtain the first sub-mold 51 shown in Figure 20.

[0227] In step 1032 , the second sub-mold 52 is cut to obtain a second arc surface 5213 and a second splicing surface 5212 .

[0228] For example, as shown in Figure 27, after being stamped by the second tapered roller mold 400, a circular second sub-mold 52 can be made. At this time, the second sub-mold 52 can be cut along the dotted line shown in Figure 27 to obtain the second sub-mold 52 shown in Figure 21.

[0229] In step 1033 , the first arc surface 5113 and the second arc surface 5213 are spliced ​​together, and the first splicing surface 5112 and the second splicing surface 5212 are made flush.

[0230] After obtaining the first sub-mold 51 shown in FIG20 and the second sub-mold 52 shown in FIG21 , the first arc surface 5113 and the second arc surface 5213 can be spliced ​​together, and the first splicing surface 5112 and the second splicing surface 5212 are aligned to obtain the mold 500 shown in FIG18 . For example, the first arc surface 5113 and the second arc surface 5213 can be spliced ​​together by gluing.

[0231] FIG29 is another flowchart of a method for manufacturing a mold according to some embodiments.

[0232] In some embodiments, as shown in FIG29 , step 101 also includes step 1013 .

[0233] In step 1013 , the first imprint layer is cured.

[0234] The first embossing layer can be made of resin glue. Alternatively, the first embossing layer can be made of heat-curable glue or UV-curable glue. In this way, when manufacturing the first belt structure 512, the above material (e.g., resin) can be cured so that the first embossing layer can form the first belt structure 512.

[0235] The curing process of the first embossed layer can be completed at different times. For example, the first embossed layer can be cured during the process of forming the plurality of nested first belt structures 512 using the first tapered roller mold. Alternatively, the first embossed layer can be cured after embossing using the first tapered roller mold is completed.

[0236] FIG30 is another flowchart of a method for manufacturing a mold according to some embodiments.

[0237] In some embodiments, as shown in FIG30 , step 102 also includes step 1023 .

[0238] In step 1023 , the second imprint layer is cured.

[0239] The second embossing layer can be made of resin glue. Alternatively, the second embossing layer can be made of heat-curable glue or UV-curable glue. In this way, when forming the second belt structure 522, the above material (e.g., resin) can be cured so that the second embossing layer can form the second belt structure 522.

[0240] It should be noted that the curing process of the second embossed layer can also be completed at a different time point. For example, the second embossed layer can be cured during the process of forming the plurality of nested second belt structures 522 using the second tapered roller mold. Alternatively, the second embossed layer can be cured after embossing using the second tapered roller mold is completed.

[0241] It should be noted that the first and second imprint layers are made of different materials and therefore require different curing methods. For example, if the first and second imprint layers are each made of a heat-curing adhesive, a heat-curing system can be used to cure the first and second imprint layers. If the first and second imprint layers are made of a UV-curing adhesive, an ultraviolet lamp can be used to cure the first and second imprint layers.

[0242] FIG31 is another flowchart of a method for manufacturing a mold according to some embodiments.

[0243] In some embodiments, as shown in FIG31 , before step 1011 , the method further includes step 1014 .

[0244] In step 1014 , the distance between the first tapered roller mold and the first structural surface 5111 is adjusted according to the thickness of the first embossing layer.

[0245] FIG32 is another flowchart of a method for manufacturing a mold according to some embodiments.

[0246] In some embodiments, as shown in FIG32 , before step 1021 , the method further includes step 1024 .

[0247] In step 1024 , the distance between the second tapered roller mold and the second structural surface 5211 is adjusted according to the thickness of the second embossing layer.

[0248] It should be noted that there can be a certain gap between the first conical roller mold and the second conical roller mold and the first structural surface 5111 and the second structural surface 5211 to avoid damage to the first structural surface 5111 and the second structural surface 5211 during the processing. Of course, the gap between the first conical roller mold and the first structural surface 5111 should be smaller than the thickness of the first embossing layer, and the gap between the second conical roller mold and the second structural surface 5211 should be smaller than the thickness of the second embossing layer.

[0249] In some embodiments, the first tapered roller mold and the second tapered roller mold can be manufactured by a CNC (Computer Numerical Control) machine with a machining accuracy of ±1 μm. Thus, the first tapered roller mold and the second tapered roller mold can have good structural accuracy.

[0250] In this way, the first belt structure 512 embossed by the first tapered roller mold and the second belt structure 522 embossed by the second tapered roller mold have high structural accuracy, the production effect of the mold 500 is better, and the structural accuracy of the Fresnel lens layer produced by the mold 500 is better, which can improve the texture of the projected image.

[0251] The sequence numbers of the steps in some embodiments of the present disclosure are only for the convenience of describing some embodiments of the present disclosure and should not be understood as limiting the order of the steps. The order of execution of the steps can be determined according to actual needs and is not limited to the order of the steps in some embodiments of the present disclosure.

[0252] Those skilled in the art will understand that the scope of the present invention is not limited to the above specific embodiments, and that certain elements of the embodiments may be modified and replaced without departing from the spirit of the present application. The scope of the present application is limited by the appended claims.

Claims

1. A projection screen configured to reflect light emitted by a projection device, comprising: a surface layer configured to protect the projection screen; a reflective layer configured to reflect light so that the light exits from the surface layer; as well as a Fresnel lens layer, wherein a side of the Fresnel lens layer close to the reflective layer is provided with a plurality of Fresnel microstructures, and the centers of the plurality of Fresnel microstructures are the same; the surface layer, the Fresnel lens layer, and the reflective layer are stacked in sequence; Wherein, the Fresnel microstructure has a first surface and a second surface connected to each other; The first surface is arranged obliquely, and the distance between an end of the first surface close to the second surface and the surface layer is greater than the distance between an end of the first surface far from the second surface and the surface layer; A first angle formed between the first surface and the surface of the surface layer on a side close to the Fresnel lens layer is related to a first target coefficient and a second angle, the first target coefficient is related to the radius of the Fresnel microstructure, and the second angle is any value within a first range.

2. The projection screen according to claim 1, wherein The projection screen satisfies at least one of the following: The first angle is the sum of the first target coefficient and the second angle; or, The first target coefficient and the radius of the Fresnel microstructure satisfy a first target formula.

3. The projection screen according to claim 1 or 2, wherein: The surface layer has a plurality of protrusions on a side away from the Fresnel lens layer; the first angle, the first target coefficient, and the second angle satisfy a second target formula, and the second target formula includes a first correction coefficient.

4. The projection screen according to claim 3, wherein: The first correction coefficient corresponding to each Fresnel microstructure in the plurality of Fresnel microstructures is different.

5. The projection screen according to claim 3 or 4, wherein: The shape of the protrusion is hemispherical; the first correction coefficient is related to the set coefficient and the second target coefficient; The second target coefficient is related to the sequence number of the multiple Fresnel microstructures. In the direction away from the center of the multiple Fresnel microstructures, the sequence number of the Fresnel microstructure increases successively, and the sequence number of the Fresnel microstructure is a positive integer.

6. The projection screen according to claim 5, wherein: The projection screen satisfies at least one of the following: The first correction coefficient is the sum of the set coefficient and the second target coefficient; or, The second target coefficient and the sequence number of the plurality of Fresnel microstructures satisfy a third target formula.

7. The projection screen according to any one of claims 1 to 6, wherein: The first angle satisfies one of the following: The refractive index of the Fresnel lens layer is any value within a second range; and The refractive index of the Fresnel lens layer is outside a second range, the first angle, the first target coefficient, and the second angle satisfy a fourth target formula, and the fourth target formula includes a second correction coefficient; wherein the second correction coefficient is negatively correlated with the refractive index of the Fresnel lens layer.

8. The projection screen according to any one of claims 1 to 7, wherein The refractive index of the surface layer is the same as the refractive index of the Fresnel lens layer.

9. The projection screen according to any one of claims 1 to 8, wherein: The center of the plurality of Fresnel microstructures is located outside the projection screen; the projection device has a light outlet, and a target projection of the light outlet is located on a side of the center of the plurality of Fresnel microstructures away from the projection screen; The target projection is the orthographic projection of the light outlet on the plane of the projection screen, and the first distance between the center of the multiple Fresnel microstructures and the projection screen is positively correlated with the second distance between the target projection and the projection screen.

10. The projection screen according to claim 9, wherein: The first distance satisfies at least one of the following: The first distance is less than two-thirds of the second distance; or, The first distance is greater than two-fifths of the second distance.

11. The projection screen according to claim 9 or 10, wherein: The projection screen is rectangular in shape; the centers of the multiple Fresnel microstructures are located on the central axis of the projection screen, and the central axis is perpendicular to the length direction of the projection screen.

12. The projection screen of claim 11, wherein: The projection screen satisfies one of the following requirements: The length of the diagonal of the projection screen is a first length; the ratio of the length of the projection screen to the width of the projection screen is a first ratio; the first distance is any value within a third range; or, The length of the diagonal of the projection screen is a second length; the ratio of the length of the projection screen to the width of the projection screen is a second ratio; the first distance is any value within a fourth range; or, The length of the diagonal of the projection screen is a third length; the ratio of the length of the projection screen to the width of the projection screen is a third ratio; and the first distance is any value within a fifth range.

13. The projection screen according to any one of claims 9 to 12, wherein: The first distance is greater than 40 mm.

14. The projection screen according to any one of claims 9 to 13, wherein The second distance is related to the width of the projection screen and the off-axis of the projection screen; The off-axis is a ratio of a third distance between the target projection and the center of the projection screen to a fourth distance between the center of the projection screen and a side of the projection screen close to the projection device.

15. A projection system comprising a projection device and a projection screen, wherein the projection screen is configured to reflect light emitted by the projection device, the projection screen comprising: a surface layer configured to protect the projection screen; a reflective layer configured to reflect light so that the light exits from the surface layer; as well as a Fresnel lens layer, wherein a side of the Fresnel lens layer close to the reflective layer is provided with a plurality of Fresnel microstructures, and the centers of the plurality of Fresnel microstructures are the same; the surface layer, the Fresnel lens layer, and the reflective layer are stacked in sequence; Wherein, the Fresnel microstructure has a first surface and a second surface connected to each other; The first surface is arranged obliquely, and the distance between an end of the first surface close to the second surface and the surface layer is greater than the distance between an end of the first surface far from the second surface and the surface layer; A first angle formed between the first surface and the surface of the surface layer on a side close to the Fresnel lens layer is related to a first target coefficient and a second angle, the first target coefficient is related to the radius of the Fresnel microstructure, and the second angle is any value within a first range.

16. The projection system according to claim 15, wherein: The projection screen satisfies at least one of the following: The first angle is the sum of the first target coefficient and the second angle; or, The first target coefficient and the radius of the Fresnel microstructure satisfy a first target formula.

17. The projection system according to claim 15, wherein: The center of the plurality of Fresnel microstructures is located outside the projection screen; the projection device has a light outlet, and a target projection of the light outlet is located on a side of the center of the plurality of Fresnel microstructures away from the projection screen; The target projection is the orthographic projection of the light outlet on the plane of the projection screen, and the first distance between the center of the multiple Fresnel microstructures and the projection screen is positively correlated with the second distance between the target projection and the projection screen.

18. A mold for use in a projection screen according to any one of claims 1 to 14, comprising: a first sub-mold, the first sub-mold comprising a first sub-mold main body and a plurality of first belt structures; the first sub-mold main body having a first structural surface; the plurality of first belt structures being sequentially arranged on the first structural surface; and a second sub-mold, the second sub-mold comprising a second sub-mold main body and a plurality of second belt structures; the second sub-mold main body is connected to the first sub-mold main body, and the second sub-mold main body has a second structural surface, the second structural surface is connected to the first structural surface and is located on the same plane; the plurality of second belt structures are arranged on the second structural surface, and the plurality of second belt structures are arranged around the plurality of first belt structures; The plurality of first band structures and the plurality of second band structures form the Fresnel microstructure.

19. The mold according to claim 18, wherein The mold is rectangular; The first sub-mold body includes a first splicing surface and a first arc surface, and the first splicing surface and the first arc surface are connected; The second sub-mold body includes a second splicing surface and a second arc surface, and the second splicing surface and the second arc surface are connected; The first arc surface and the second arc surface are connected, and at least a portion of the first splicing surface and at least a portion of the second splicing surface are flush with each other.

20. A mold master having a Fresnel microstructure; the Fresnel microstructure is formed by embossing the mold according to claim 18 or 19.

Images