Projection screen, manufacturing method thereof and projection system

Abstract

The embodiment of the invention provides a projection screen, a manufacturing method thereof and a projection system. The projection screen comprises a surface functional layer, a Fresnel lens layer and a reflecting layer. The Fresnel lens layer comprises a plurality of lens units, and the reflecting layer is at least located on the lens surfaces of the lens units. The projection screen provided by the embodiment of the invention can achieve the effects of absorbing the incident ambient light, improving the black brightness of the projection screen, selectively reflecting the incident projection light, and absorbing the light of other wavebands, so as to improve the contrast of a projected image, improve the gain uniformity of the projection screen and the like.

Description

Projection screen, method for producing the same, and projection system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Chinese patent application No. 202310422256.0 filed with the State Intellectual Property Office of China on April 19, 2023, and entitled “Projection screen, its manufacturing method and projection system”, the entire contents of which are incorporated herein by reference; this application claims the priority of Chinese patent application No. 202310548405.8 filed with the State Intellectual Property Office of China on May 16, 2023, and entitled “A projection screen and projection system”, the entire contents of which are incorporated herein by reference Please refer to the application; this application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on August 25, 2023, with application number 202311078929.1 and application name “Projection screen and projection system”, all of which are incorporated by reference into this application; this application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on November 2, 2023, with application number 202311449292.2 and application name “A method for manufacturing a projection screen”, all of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of projection technology, and in particular to a projection screen, a manufacturing method thereof, and a projection system. Background Art

[0004] As display products continue to grow in size, the market for projection display products, as large-screen alternatives to LCD and organic electroluminescent (EL) TVs, is rapidly expanding due to power consumption, weight, and size considerations. Laser TVs, which utilize ultra-short-throw projection equipment, are experiencing rapid growth due to their high image quality and large screen size.

[0005] Current projection systems typically work with projection screens. Projection light is emitted by the projection device, then incident on the projection screen. After being reflected by the screen, it reaches the human eye, where the projected image is perceived. The projection screen incorporates a Fresnel lens layer, which reflects the light toward the viewer.

[0006] Summary of the Invention

[0007] According to a first aspect of an embodiment of the present application, a projection screen is provided, comprising:

[0008] Surface functional layer;

[0009] A Fresnel lens layer is located on one side of the surface functional layer; the Fresnel lens layer includes a plurality of lens units, the plurality of lens units are arranged in concentric circles that expand in sequence along the radial direction; the lens units include lens surfaces that are tilted relative to the plane where the surface functional layer is located; and

[0010] a reflective layer, covering at least the inclined surface of the lens unit;

[0011] The inclination angle of the lens surface of each lens unit is sufficient to reflect the light emitted by the projection device to the reflective layer on the lens surface toward the viewer;

[0012] The lens units are axially symmetrically distributed, the symmetry axis of each lens unit is perpendicular to the horizontal direction, and the center of the lens unit is located on the straight line where the symmetry axis is located; the inclination angle of the lens surface of at least one lens unit in the multiple groups of lens units at a first position is greater than the inclination angle at a second position, and the distance from the first position to the symmetry axis is greater than the distance from the second position to the symmetry axis.

[0013] In a second aspect of the embodiment of the present application, a projection system is provided, comprising

[0014] Projection equipment, used for emitting projection light; and

[0015] A projection screen, located on the light-emitting side of the projection device, the projection screen being the aforementioned projection screen;

[0016] Wherein, the projection device is an ultra-short-throw laser projection device; the projection device includes:

[0017] A three-color laser light source device for emitting three-primary-color lasers;

[0018] a light modulation component, located on the light-emitting side of the three-color laser light source device, for modulating the laser light emitted by the three-color laser light source device; and

[0019] The projection lens is located on the light-emitting side of the light modulation component.

[0020] According to a third aspect of the embodiments of the present application, a method for manufacturing a projection screen is provided, comprising:

[0021] A Fresnel lens layer manufacturing process comprises: manufacturing a Fresnel lens layer; a surface of the Fresnel lens layer having a plurality of lens units, each of the lens units being arranged in a concentric circle and expanding in sequence along a radial direction; the lens units comprising a lens surface and a non-lens surface connected to each other;

[0022] a wavelength selective reflection layer manufacturing process: forming a wavelength selective reflection layer on the surface of the lens unit; the thickness of the wavelength selective reflection layer along the plane perpendicular to the projection screen increases as the radius of each lens unit increases; and

[0023] Surface functional layer manufacturing step: forming a surface functional layer on one surface of the Fresnel lens layer with the wavelength selective reflection layer.

[0024] According to a fourth aspect of the embodiments of the present application, a method for manufacturing a projection screen is provided, comprising:

[0025] A Fresnel lens layer is fabricated; one side surface of the Fresnel lens layer comprises a plurality of arc-shaped lens units, each arc-shaped lens unit being concentrically arranged; each lens unit comprises a lens surface and a non-lens surface connected to each other, the lens surface being inclined relative to the plane of the projection screen, and the non-lens surface being used to connect the lens surfaces;

[0026] An evaporation source is provided at a set position of the Fresnel lens layer to form a reflective layer on the lens surfaces of the plurality of lens units; the evaporation source is located on a side of the Fresnel lens layer having the plurality of lens units, and a set distance is provided between the evaporation source and the plurality of lens units;

[0027] A surface functional layer is formed on the side of the Fresnel lens layer facing away from the reflective layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is a schematic structural diagram of a projection system provided in an embodiment of the present application;

[0029] FIG2 is a schematic diagram of a cross-sectional structure of a projection screen in the related art;

[0030] FIG3 is a schematic diagram of one of the projection effects provided by an embodiment of the present application;

[0031] FIG4 is a schematic diagram of partitions of a projection screen provided in an embodiment of the present application;

[0032] FIG5 is a schematic diagram of a cross-sectional structure of a projection screen according to an embodiment of the present application;

[0033] FIG6 is a schematic diagram of a planar structure of a Fresnel lens layer provided in an embodiment of the present application;

[0034] FIG7 is a second schematic diagram of the projection effect provided by an embodiment of the present application;

[0035] FIG8 is one of the curves showing the variation of the inclination angle of the inclined surface of the Fresnel structure at different positions provided by an embodiment of the present application;

[0036] FIG9 is a schematic diagram of a cross-sectional structure of the projection screen along the symmetry axis II' in FIG6;

[0037] FIG10 is a second curve showing the variation of the inclination angle of the inclined surface of the Fresnel structure at different positions provided by an embodiment of the present application;

[0038] FIG11 is a second schematic diagram of the cross-sectional structure of a projection screen provided in an embodiment of the present application;

[0039] FIG12 is a third schematic diagram of the cross-sectional structure of the projection screen provided in an embodiment of the present application;

[0040] FIG13 is a fourth schematic diagram of the cross-sectional structure of the projection screen provided in an embodiment of the present application;

[0041] FIG14 is a schematic diagram of the planar structure of the surface functional layer provided in an embodiment of the present application;

[0042] FIG15 is a fifth schematic diagram of the cross-sectional structure of a projection screen provided in an embodiment of the present application;

[0043] FIG16 is a sixth schematic diagram of the cross-sectional structure of a projection screen provided in an embodiment of the present invention;

[0044] FIG17 is a seventh schematic diagram of the cross-sectional structure of a projection screen provided by an embodiment of the present invention;

[0045] FIG18 is an eighth schematic diagram of the cross-sectional structure of a projection screen provided by an embodiment of the present invention;

[0046] FIG19 is a ninth schematic diagram of a cross-sectional structure of a projection screen provided in an embodiment of the present application;

[0047] FIG20 is a tenth schematic diagram of the cross-sectional structure of a projection screen provided in an embodiment of the present application;

[0048] FIG21 is a schematic diagram of a structure of a wavelength selective reflection layer according to an embodiment of the present application;

[0049] FIG22 is a second schematic structural diagram of a wavelength selective reflection layer provided in an embodiment of the present application;

[0050] FIG23 is a third structural schematic diagram of a wavelength selective reflection layer provided in an embodiment of the present application;

[0051] FIG24 is a reflectivity curve of the wavelength selective reflection layer for light of different wavelength bands provided by an embodiment of the present application;

[0052] FIG25 is a schematic diagram of the optical path of projection light incident on a projection screen according to an embodiment of the present application;

[0053] FIG26 is one of the coating schematic diagrams provided in an embodiment of the present application;

[0054] FIG27 is a reflectivity curve of a wavelength-selective reflective layer producing a wavelength shift according to an embodiment of the present application;

[0055] FIG28 is a second schematic diagram of coating provided in an embodiment of the present application;

[0056] FIG29 is a curve showing changes in optical parameters of a complete metal oxide provided in an embodiment of the present application;

[0057] FIG30 is a curve showing changes in optical parameters of metal suboxides provided in an embodiment of the present application;

[0058] FIG31 is a curve showing the change in oxidation number with the flow rate of reactive gas in the reactive sputtering process controlled by plasma luminescence provided by an embodiment of the present application;

[0059] FIG32 is a curve showing the change of oxygen partial pressure with the flow rate of reactive gas in the reactive sputtering process controlled by plasma luminescence provided by an embodiment of the present application;

[0060] FIG33 is a curve showing the variation of the extinction coefficient with the reactive gas flow rate in the reactive sputtering process controlled by plasma luminescence provided by an embodiment of the present application;

[0061] FIG34 is a curve showing the change in film forming rate with the flow rate of reactive gas in the reactive sputtering process controlled by plasma luminescence provided by an embodiment of the present application;

[0062] FIG35 is a schematic diagram of the structure of a projection device provided in an embodiment of the present application;

[0063] FIG36 is a flowchart of a method for manufacturing a projection screen according to an embodiment of the present application;

[0064] FIG37 is a schematic structural diagram of a film-forming cathode portion of a sputtering device in the related art;

[0065] FIG38 is a schematic structural diagram of a film-forming cathode portion of a sputtering device provided in an embodiment of the present application;

[0066] FIG39 is a schematic diagram of a sputtering process according to an embodiment of the present application;

[0067] FIG40 is a second schematic diagram of the planar structure of the Fresnel lens layer provided in an embodiment of the present application;

[0068] FIG41 is a schematic diagram of the cross-sectional structure along the AA' direction in FIG40;

[0069] FIG42 is a second flowchart of the method for manufacturing a projection screen provided in an embodiment of the present application;

[0070] FIG43 is a schematic cross-sectional view of the positional relationship between the evaporation source and the Fresnel lens layer provided in an embodiment of the present application;

[0071] FIG44 is a schematic diagram of a planar structure showing the positional relationship between an evaporation source and a Fresnel lens layer according to an embodiment of the present application;

[0072] FIG45 is a second schematic planar structural diagram of the positional relationship between the evaporation source and the Fresnel lens layer provided in an embodiment of the present application;

[0073] FIG46 is a schematic diagram of the cross-sectional structure along the II' direction in FIG44;

[0074] FIG47 is a schematic cross-sectional view showing the positional relationship among the evaporation source, the baffle, and the Fresnel lens layer according to an embodiment of the present application;

[0075] FIG48 is a planar structural diagram illustrating the positional relationship between a baffle and a Fresnel lens layer provided in an embodiment of the present application;

[0076] FIG49 is a second schematic cross-sectional view of the positional relationship between the evaporation source, the baffle, and the Fresnel lens layer according to an embodiment of the present application;

[0077] FIG50 is a schematic diagram of a planar structure showing the positional relationship among an evaporation source, a baffle, and a Fresnel lens layer according to an embodiment of the present application;

[0078] FIG51 is a second schematic planar structural diagram of the positional relationship among the evaporation source, the baffle, and the Fresnel lens layer provided in an embodiment of the present application;

[0079] FIG52 is a third schematic cross-sectional structural diagram illustrating the positional relationship between the evaporation source, the baffle, and the Fresnel lens layer provided in an embodiment of the present application;

[0080] FIG53 is a schematic diagram of the cross-sectional structure along the BB' direction in FIG40;

[0081] FIG54 is a schematic diagram showing the positional relationship among the evaporation source, the baffle, and the Fresnel lens layer along the cross section shown in FIG53 ;

[0082] FIG55 is a third schematic diagram of the planar structure of the evaporation source, baffle, and Fresnel lens layer provided in an embodiment of the present application;

[0083] FIG56 is a fourth schematic diagram of the planar structure of the evaporation source, baffle, and Fresnel lens layer provided in an embodiment of the present application;

[0084] Figure 57 is a schematic diagram of the planar structure of the evaporation source, baffle and lens structure layer provided in an embodiment of the present application. DETAILED DESCRIPTION

[0085] In order to make the features and advantages of the present application more obvious and easy to understand, the present application will be further described below with reference to the accompanying drawings and examples. However, the example embodiments can be implemented in various forms and should not be understood as being limited to the embodiments set forth herein; on the contrary, these embodiments are provided to make the present application more comprehensive and complete, and to fully convey the concepts of the example embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and their repeated descriptions will be omitted. The words expressing position and direction described in this application are all explained using the accompanying drawings as examples, but changes can be made as needed, and all changes are included in the scope of protection of this application. The drawings in this application are only used to illustrate relative position relationships and do not represent true proportions.

[0086] With the popularity of laser display products, the market for laser TVs is rapidly expanding as a large-screen alternative to LCD and organic EL TVs. To achieve better brightness and display quality, projection equipment is generally used in conjunction with a projection screen.

[0087] FIG1 is a schematic structural diagram of a projection system provided in an embodiment of the present application.

[0088] As shown in FIG1 , the projection system includes a projection device 2 and a projection screen 1 .

[0089] The projection screen 1 is located on the light-emitting side of the projection device 2. The audience faces the projection screen 1. The projection device 2 emits projection light. The projection light is incident on the projection screen 1 and is emitted toward the audience through the projection screen 1, so that the audience can see the projected image.

[0090] When projection device 2 and the audience are on the same side of projection screen 1, the projection system is a front projection system. When projection device 2 and the audience are on opposite sides of projection screen 1, the projection system is a rear projection system. In a front projection system, projection device 2 emits projection light toward projection screen 1, which then reflects the projection light toward the audience, allowing them to view the projected image. In a rear projection system, projection device 2 emits projection light toward projection screen 1, which then transmits the projection light through projection screen 1 toward the audience, allowing them to view the projected image.

[0091] Ultra-short-throw projection equipment has the characteristics of short projection distance and large projection image, and is very suitable for application in the home field. The projection system provided in the embodiment of the present application can adopt ultra-short-throw projection equipment. The embodiment of the present application uses the front-projection ultra-short-throw projection system as an example to specifically illustrate the structure of the projection screen. The front-projection ultra-short-throw projection system usually installs the projection screen 1 on the wall or hangs it at a high place. The projection device 2 is located below the projection screen 1, and the projection light is emitted from the bottom of the projection screen 1 to the upper and oblique direction to the projection screen 1. Since the ultra-short-throw projection system has a small projection ratio, a larger-sized projection image can be obtained while reducing the distance between the projection device 2 and the projection screen 1, which is very suitable for application in scenes such as laser TV.

[0092] FIG. 2 is a schematic diagram of a structure of a projection screen in the related art.

[0093] As shown in Figure 2, the projection screen includes a surface layer 10, a Fresnel lens layer 12, and a reflective layer 13. The surface layer 10 and the Fresnel lens layer 12 are bonded together via an adhesive layer 14. The Fresnel lens layer 12 includes multiple lens units, each arranged in a concentric circular pattern that expands radially. The reflective layer 13 is provided on the surface of each lens unit. The lens units are configured to reflect light L emitted by the projection device 1 upon entering the reflective layer 13 on the surface of the Fresnel lens layer 12 toward the viewer's location, allowing the projection light to enter the human eye and be viewed as a projected image.

[0094] FIG3 is one of the schematic diagrams of the projection effect provided in an embodiment of the present application.

[0095] For ease of illustration, Figure 3 shows only one lens unit 121. In practice, each lens unit 121 faces the same problem. Since lens units 121 are typically spherical mirrors, meaning each lens unit 121 is located on a spherical mirror with the same radius of curvature, and spherical mirrors inherently exhibit astigmatism, as shown in Figure 3, lens units 121 are unable to reflect incident light rays toward the same location, resulting in poor light collection and, consequently, poor gain uniformity across the projection screen.

[0096] FIG4 is a schematic diagram of partitions of a projection screen provided in an embodiment of the present application.

[0097] As shown in Figure 4, a projection screen is typically mounted on a wall or hung high. If the projection screen is rectangular, its bottom edge is parallel to the horizontal direction, and its sides are parallel to the vertical direction, with the vertical direction being perpendicular to the horizontal. When calculating the gain uniformity of a projection screen, the screen is divided into three equal parts horizontally and vertically, thus dividing it into nine regions S1 to S9. Gain uniformity is measured as the ratio between the average gain of regions S1, S3, S7, and S9 and the gain of region S5. When the gain of region S5 is set to the maximum, the gain uniformity threshold of the projection screen is approximately 70%.

[0098] FIG5 is one of the schematic cross-sectional structural diagrams of the projection screen provided in an embodiment of the present application.

[0099] As shown in FIG5 , the projection screen includes a surface functional layer 11 , a Fresnel lens layer 12 and a reflective layer 13 .

[0100] The surface functional layer 11 can be located on the outermost surface of the projection screen. In the embodiment of the present application, the surface functional layer 11 is located on the side closest to the audience, thereby protecting the projection screen. In addition, the surface functional layer 11 can also be processed in a variety of ways according to different needs to achieve the effects of expanding the viewing angle, resisting ambient light reflection, and resisting ceiling reflection.

[0101] FIG6 is a schematic diagram of the planar structure of the Fresnel lens layer provided in an embodiment of the present application.

[0102] As shown in Figures 5 and 6, the Fresnel lens layer 12 is located on one side of the surface functional layer 11, specifically on the side opposite to the viewer of the surface functional layer 11. The Fresnel lens layer 12 includes a plurality of lens units 121 arranged according to a set rule.

[0103] Depending on the application scenario and manufacturing process, the lens unit 121 can adopt different structures. As shown in Figure 6, multiple groups of lens units 121 are arranged in concentric circles that expand in sequence along the radial direction. When the projection screen is used in an ultra-short-throw projection system, the center O of the concentric lens units 121 is usually not located within the projection screen, and the projection screen does not contain a complete lens unit, but rather a partial arc of the lens unit. When the projection device emits projection light from the bottom side of the projection screen to the projection screen, the center of the lens unit 121 can be located outside the projection screen and close to the bottom side. In this case, the radius of each lens unit 121 gradually increases as it moves away from the bottom side.

[0104] As shown in Figure 5, lens unit 121 includes a connected lens surface x1 and a non-lens surface x2. Lens surface x1 is tilted relative to surface functional layer 11. The tilt angle of lens surface x1 is set according to the incident angle of the projection light, and is used to reflect the output light of the projection device toward the viewer when it enters the reflective layer on its surface. Non-lens surface x2 is connected to lens surface x1.

[0105] The reflective layer 13 covers at least the lens surface of each lens unit 121 of the Fresnel lens layer 12. The lens surface of the lens unit has a specific tilt angle, so that the reflective layer 13 covering its surface also has a corresponding tilt angle. As a result, when the projection light is incident on the reflective layer 13 on the surface of the lens unit, it is reflected by the reflective layer 13 toward the position of the audience.

[0106] In some embodiments, the reflective layer 13 can be a metal film formed using an evaporation or sputtering process. This metal film covers the surface of the lens unit 121, so that the surface of the metal film has the same undulation as the lens unit. The surface of the metal film can maintain the designed reflection angle of the lens unit's lens facing the incident light. The metal film can be made of metals such as aluminum, silver, and titanium, which are not limited here. When using the structure shown in Figure 5, if the reflective layer 13 is located on the back of the projection screen, it can also be coated with aluminum paste or silver paste.

[0107] As shown in Figure 6, the projection screen is typically rectangular, comprising four sides, with adjacent sides perpendicular to each other. When in use, the projection screen is typically mounted on a wall or hung high, with the bottom and top sides typically parallel to the horizontal direction x, and the sides perpendicular to the horizontal direction. In the embodiment of the present application, the projection screen is an axisymmetric figure, with its axis of symmetry II' perpendicular to the bottom side. The lens units 121 are arranged axially symmetrically about the axis of symmetry II', with the center of each lens unit located on the axis of symmetry II'.

[0108] In an embodiment of the present application, the tilt angle of the lens surface x1 of at least one lens unit 121 at a first position is greater than the tilt angle at a second position, wherein the distance from the first position to the symmetry axis II' is greater than the distance from the second position to the symmetry axis II'. Thus, the tilt angle of the lens surface of the lens unit 121 can satisfy the following requirement: it increases as the perpendicular distance from the lens surface x1 to the symmetry axis II' increases. As shown in FIG6 , each lens unit 121 can be divided into a left and a right portion along the symmetry axis II', wherein the tilt angle of the lens surface x1 of the left lens unit gradually increases along the first direction x1, and the tilt angle of the lens surface x1 of the right lens unit gradually increases along the second direction xr. The tilt angles of the lens surfaces of the same lens unit are symmetrical about the symmetry axis II', i.e., in the same lens unit 121, the tilt angles of the lens surfaces at positions with equal perpendicular distances from the symmetry axis II' on the left and right sides are equal, i.e., in the same lens unit 121, the tilt angles of the lens surfaces at positions symmetrical about the symmetry axis II' are equal.

[0109] FIG. 7 is a second schematic diagram of the projection effect provided in an embodiment of the present application.

[0110] In this embodiment of the present application, the tilt angle of the lens surface of at least one lens unit is set to increase as the vertical distance from the lens surface to the symmetry axis II' increases. That is, the tilt angle of the lens surfaces at the two sides of the same lens unit is larger, as shown in Figure 7. This can concentrate more of the light incident on the two sides toward the center. Comparing Figures 4 and 7, it can be seen that this arrangement of the present application can optimize the light collection effect of the lens unit, thereby improving the gain uniformity of the projection screen.

[0111] Based on the above principle, in order to concentrate more light from the edge of the projection screen toward the center and improve the gain uniformity of the projection screen, the embodiment of the present application sets all lens units in the projection screen so that the inclination angle of the lens surface increases with the increase of the vertical distance from the lens surface to the symmetry axis II' of the projection screen, thereby concentrating the light toward the center to the greatest extent.

[0112] As shown in Figure 6, if the intersection positions of the lens unit 121 and the bottom side of the projection screen are A and D, the intersection point of the bottom side and the symmetry axis II' is C, and the intersection point of the upper side of the projection screen and the symmetry axis II' is B, then the inclination angle of the lens surface at each position of the lens unit satisfies the rule shown in Figure 8. Figure 8 is one of the change curves of the inclination angle of the lens surface of the lens unit at different positions provided by an embodiment of the present application. It can be seen from Figure 8 that the change in the inclination angle of the lens surface of the same lens unit satisfies the sine function. From position A to position B and then to position D, the inclination angle of the lens surface of the lens unit first gradually decreases and then gradually increases, changing in a sinusoidal curve.

[0113] For a lens unit 121, the A / D position is the position of the lens unit near the two edges of the projection screen, and the B position is the center of the lens unit. In order for the lens unit to focus light from both sides toward the center, the inclination angle of the lens surface at the two sides needs to be larger than the inclination angle at the center. This allows light incident on the lens unit to be reflected more toward the center, achieving the effect of focusing light toward the center.

[0114] FIG. 9 is a schematic diagram of the cross-sectional structure of the projection screen along the symmetry axis II′ in FIG. 6 .

[0115] As shown in FIG9 , the projection device typically emits projection light L toward the projection screen from a position in the middle below the projection screen. Since the projection device is fixed in position, the incident angle and direction of the projection light L are different when it strikes different positions on the projection screen. To ensure that the projection light is reflected toward the viewer, each lens unit needs to be designed as a concentric circle that expands radially, and the inclination angle of the lens surface x1 of each lens unit along the same radial direction is different. In the embodiment of the present application, the inclination angle of the lens surface of each lens unit increases radially as the radius of the lens unit increases.

[0116] Taking Figure 9 as an example, the tilt angle of the lens surface of the same lens unit varies at different positions (e.g., positions A, B, and D). Therefore, the tilt angles of the lens surfaces of the lens units along different directions are not comparable. However, along the same direction, such as radial direction y in Figure 9, the radius of each lens unit increases successively, and the tilt angle of the lens surface x1 of each lens unit increases successively. That is, the tilt angle of the lens surface x1 of each lens unit along radial direction y satisfies: θ1 < θ2 < θ3. Lens units with larger radius are closer to the edge of the projection screen. In order to reflect the projection light incident on the lens unit toward the center, the tilt angle of the lens surface of the lens unit closer to the edge needs to be set larger. Therefore, the tilt angle of the lens surface of the lens unit needs to be set to increase with increasing radius along the radial direction.

[0117] FIG. 10 is a second curve showing changes in the tilt angle of the lens surface of the lens unit at different positions provided by an embodiment of the present application.

[0118] As shown in FIG10 , the variation pattern of the tilt angle of the lens surface of each lens unit satisfies a sine function. The larger the radius of the lens unit, the larger the range occupied by the lens unit on the plane of the projection screen. Therefore, the more dramatic the change in the tilt angle of the lens surface of the lens unit from the edge position to the middle position, the greater the amplitude of the sine curve it satisfies. According to the above-mentioned pattern, the amplitude of the sine function satisfied by the tilt angle of the lens surface of each lens unit in the embodiment of the present application increases as the radius of the lens unit increases. Taking FIG10 as an example, the sine curve f1 represents the variation pattern of the tilt angle of the lens surface of the lens unit with a larger radius, and the sine curve f2 represents the variation pattern of the tilt angle of the lens surface of the lens unit with a smaller radius. As can be seen from FIG10 , the amplitude of the sine curve f1 satisfied by the tilt angle of the lens surface of the lens unit with a larger radius is greater than the amplitude of the sine curve f2 satisfied by the tilt angle of the lens surface of the lens unit with a smaller radius.

[0119] In some embodiments, the projection screen can be used in conjunction with an ultra-short-throw projection device. The ultra-short-throw projection system can project large-scale images. Based on the current projection screen size, if the radius of the lens unit is within 2000 mm, then the change in the tilt angle of the lens surface of the same lens unit (m in Figure 10) is greater than 0 and less than or equal to 2.25°. As the radius of the lens unit increases, the change in the tilt angle of its lens surface gradually increases. Experimental verification has shown that the change in the tilt angle of the lens surface of the lens unit increases with the size of the projection screen. When the radius of the lens unit is within 2000 mm, the maximum change in the tilt angle of the lens surface of the same Fresnel structure does not exceed 2.25°.

[0120] It is worth noting that the embodiments of this application are only illustrative of a case where the radius of the lens unit in the projection screen is within 2000 mm. If the size of the projection screen is further increased, so that the radius of the lens unit exceeds 2000 mm, the change in the tilt angle of the lens surface of the lens unit may exceed 2.25°. The embodiments of this application do not limit the specific value of the change.

[0121] FIG11 is a second schematic diagram of the structure of the projection screen provided in an embodiment of the present application.

[0122] As shown in Figures 5 and 11 , the projection screen further includes an adhesive layer 14 positioned between the surface functional layer 11 and the Fresnel lens layer 12 for bonding the surface functional layer 11 to the Fresnel lens layer 12. Adhesive layer 14 can be made of an acrylic or silicone adhesive, or a UV-curable resin material, without limitation.

[0123] In some embodiments, as shown in FIG5 , the lens units 121 of the Fresnel lens layer 12 are located on a side away from the surface functional layer 11 , and the adhesive layer 14 is used to bond the surface functional layer 11 to the surface of the Fresnel lens layer 12 opposite to the lens units 121 .

[0124] In some embodiments, as shown in Figure 11 , the lens units 121 of the Fresnel lens layer 12 are located on the side facing the surface functional layer 11. The adhesive layer 14 is used to bond the surface functional layer 11 to the reflective layer 13 on the surface of the lens units 121. When the lens units 121 are positioned near the adhesive layer 14, the adhesive layer 14 protects the reflective layer 13. In this case, since the Fresnel lens layer 12 is located farthest from the viewer and no light enters the Fresnel lens layer 12, the requirements for light transmittance and damage resistance of the Fresnel lens layer 12 are relaxed. Expensive optical materials are no longer required to manufacture the Fresnel lens layer 12, and it can be made from relatively inexpensive industrial materials, thereby reducing production costs.

[0125] In some embodiments, as shown in Figure 11, the Fresnel lens layer 12 includes a first substrate 122, the surface of the first substrate 122 facing the surface functional layer 11 and the surface opposite to the surface functional layer 11 are both flat surfaces, and the lens unit 121 is located on the first substrate 122.

[0126] Among them, the first substrate 122 can be made of materials such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), triacetylcellulose (TAC), cycloolefin polymer (COP), thermoplastic polyurethane (TPU), polyvinyl chloride (PVC), polyimide (PI), polyamide (PA), polyethylene (PE), and polypropylene (PP).

[0127] The lens unit 121 can be formed by applying a UV curable resin to a mold having the shape of the lens unit and then UV curing the UV curable resin by imprinting it with the first substrate 122. In addition, the lens unit 121 can also be made of other materials and other manufacturing methods, which are not limited here.

[0128] FIG12 is a third structural schematic diagram of the projection screen provided in an embodiment of the present application.

[0129] In some embodiments, as shown in Figure 12, the Fresnel lens layer 12 is a monolithic structure, with one surface of the Fresnel lens layer 12 being a lens unit 121 and the other surface being a flat surface. The monolithic structure of the Fresnel lens layer 12 eliminates the need to bond the substrate to the lens unit, further simplifying the manufacturing process. The monolithic Fresnel lens layer 12 can be manufactured using thermoforming, which is not a limitation herein.

[0130] FIG13 is a fourth structural schematic diagram of the projection screen provided in an embodiment of the present application, and FIG14 is a planar structural schematic diagram of the surface functional layer provided in an embodiment of the present application.

[0131] In some embodiments, the surface functional layer 11 has a light diffusion function. As shown in FIG13 , the surface functional layer 11 may include a second substrate 111 and a diffusion layer 112. The second substrate 111 serves as a substrate for the diffusion layer 112. The second substrate 111 is in contact with the adhesive layer 14. The diffusion layer 112 is located on the surface of the second substrate 111 opposite to the adhesive layer 14.

[0132] Current projection systems typically use laser light sources. Lasers have high collimation, resulting in a smaller divergence angle for the projected light. The light reflected from the projection screen is highly collimated, which also results in a smaller field of view. By providing a diffusion layer 112, the angle of light emitted after passing through the diffusion layer can be diversified, resulting in a certain divergence angle for the light ultimately emitted from the projection screen, increasing the viewer's field of view for the projected image. Furthermore, the diffusion layer 112 helps suppress laser speckle and optimize the projected image.

[0133] The diffusion layer 112 can be formed on the surface of the second substrate 111 by adding diffusion particles to the resin material. The diffusion particles can be, but are not limited to, silicon dioxide particles, aluminum oxide particles, titanium oxide particles, cerium oxide particles, zirconium oxide particles, tantalum oxide particles, zinc oxide particles, magnesium fluoride particles, etc.

[0134] The second substrate 111 can be made of, but is not limited to, PET, PEN, PC, PMMA, TAC, COP, TPU, PVC, PI, PA, PE, PP and other materials.

[0135] In some embodiments, the diffusion layer 112 can exhibit anisotropic diffusion properties, meaning that the diffusion angles vary across different directions. As shown in Figure 14 , the diffusion angle of the diffusion layer 112 along the horizontal direction x is greater than the diffusion angle along the vertical direction y. The horizontal direction x and the vertical direction y are both different directions within the plane of the projection screen. The horizontal direction x is parallel to the bottom edge of the projection screen, while the vertical direction y is perpendicular to the horizontal direction and parallel to the symmetry axis II' of the projection screen. The vertical direction y corresponds to the height of the projection screen when the viewer is viewing the projection screen. If the diffusion layer has a larger vertical diffusion angle, light from the ceiling will also be diffused, resulting in increased blackout brightness of the projection screen. A larger horizontal diffusion angle can also dilate the left and right viewing angles of the projection screen. Therefore, by ensuring that the diffusion layer has a larger anisotropic diffusion angle along the horizontal direction x than along the vertical direction y, the horizontal viewing angle of the projection screen can be increased while preventing increased blackout brightness.

[0136] In a specific implementation, by manufacturing the diffusion layer into a structure in which ridges are arranged along the vertical direction y, it is possible to achieve an effect in which the diffusion angle in the horizontal direction x is greater than the diffusion angle in the vertical direction y.

[0137] As shown in Figure 4, in related art, when the tilt angle of the lens surface of a single lens unit is constant, the lens unit is a spherical mirror, which produces astigmatism. Consequently, light from areas S1, S4, and S7, as well as areas S3, S6, and S9 of the projection screen, will be directed horizontally to the sides, resulting in poor gain uniformity across the projection screen. When an anisotropic diffusion layer is used, whose diffusion angle in the vertical direction y is smaller than that in the horizontal direction x, the increased horizontal diffusion further degrades gain uniformity across the projection screen. Increasing the tilt angle of the lens unit's lens surface to suppress horizontal light diffusion will cause light from areas S2 and S5 of the projection screen to be emitted downward, resulting in a decrease in frontal brightness. Therefore, to overcome this problem, the diffusion angle of the diffusion layer in the vertical direction y is increased, allowing light to diffuse further from the bottom to the top, thereby improving gain uniformity across the projection screen. As described above, increasing the diffusion angle of the diffusion layer in the vertical direction y increases black field brightness, which still affects the display quality.

[0138] In the embodiment of the present application, the inclination angle of the lens surface of the lens unit is set so that the inclination angle at the edge position is greater than the inclination angle at the middle position, so that the light can be concentrated more toward the middle position. At the same time, an anisotropic diffusion layer is used in which the diffusion angle in the horizontal direction x is greater than the diffusion angle in the vertical direction y. This can suppress the brightness reduction of the projection screen in areas S2 and S5 while reducing the black field brightness.

[0139] The present embodiment also tests the gain uniformity of a projection screen fabricated according to the above-described concept. The specific fabrication process is as follows: An 80-inch lens unit is fabricated on the surface of a 250μm-thick PET substrate to form a Fresnel lens layer. A reflective layer is then formed on the surface of the lens unit by evaporating aluminum. Next, a diffusion layer is fabricated on the surface of a 250μm-thick PET substrate, with a vertical diffusion angle smaller than the horizontal diffusion angle. The two PET substrates are bonded together using a transparent adhesive to form the projection screen.

[0140] As shown in Figure 4, the same method is used to measure the gain uniformity of the projection screen, using the ratio of the average gain of regions S1, S3, S7, and S9 to the gain of region S5. By setting the tilt angle of the lens surface of the lens unit in the projection screen so that the tilt angle at the sides is greater than the tilt angle at the center, the gain uniformity of the projection screen can be improved to over 80%. With a reasonable tilt angle design, the gain uniformity of the projection screen can be achieved to 100%.

[0141] FIG15 is a fifth schematic diagram of the cross-sectional structure of the projection screen provided in an embodiment of the present application.

[0142] In some embodiments, as shown in Figure 15 , the surface functional layer 11 comprises only a second substrate 111. This second substrate 111 contacts an adhesive layer 14 and is bonded to the Fresnel lens layer 12 via the adhesive layer 14. The material of the second substrate 111 includes a diffusing material. Thus, when the second substrate 111 is formed, it has light diffusing properties and a certain degree of haze. The inclusion of the diffusing material in the second substrate 111 can expand the viewing angle and reduce light reflection, thereby preventing light from forming a clear image on the ceiling. This anti-glare effect enhances the viewing experience.

[0143] FIG16 is a sixth schematic diagram of the cross-sectional structure of the projection screen provided in an embodiment of the present invention.

[0144] In some embodiments, as shown in FIG16 , the surface functional layer 11 includes only a second substrate 111 , which is in contact with an adhesive layer 14 and is bonded to the Fresnel lens layer 12 via the adhesive layer 14 . The surface of the second substrate 111 opposite the adhesive layer 14 is uneven. This uneven surface can be formed by sandblasting or alkali treating the surface of the second substrate 111 , which is not limited here. The uneven surface of the second substrate 111 can provide a certain light diffusion and atomization effect, thereby expanding the viewing angle and preventing ceiling reflections.

[0145] FIG17 is a seventh schematic diagram of the cross-sectional structure of a projection screen provided in accordance with an embodiment of the present invention, and FIG18 is an eighth schematic diagram of the cross-sectional structure of a projection screen provided in accordance with an embodiment of the present invention.

[0146] In some embodiments, as shown in Figures 17 and 18, the projection screen may also include only a Fresnel lens layer 12, a reflective layer 13, and a surface functional layer 11. The lens unit 121 of the Fresnel lens layer 12 is arranged on the side facing the viewer, the reflective layer 13 is located on the surface of the lens unit 121, and the surface functional layer 11 is located on the surface of the reflective layer 13. In this case, the surface functional layer adopts a diffusion layer 112 covering the reflective layer 13. The diffusion layer 112 can be formed on the surface of the reflective layer 13 by coating, spraying, etc. The projection screen structure shown in Figures 17 and 18 can effectively reduce the thickness of the projection screen. The Fresnel lens layer 12 can adopt the structure shown in Figure 17, including a first substrate 122 and a lens unit 122 located on the first substrate 122, or it can adopt the integrated structure shown in Figure 18.

[0147] FIG19 is a ninth schematic diagram of the cross-sectional structure of the projection screen provided in an embodiment of the present application.

[0148] In some embodiments, as shown in FIG19 , the adhesive layer 14 may contain a light-absorbing material and be colored to improve the black brightness of the projection screen. In some embodiments, the adhesive layer 14 may be colored with a dark material such as carbon black or a dye to deepen the color of the adhesive layer 14, although this is not a limitation herein.

[0149] As shown in Figure 2, projection light L emitted by the projection device enters the projection screen, is reflected by reflective layer 13, and then exits the projection screen toward the viewer. Simultaneously, ambient light C can also enter the projection screen. Similarly, some of this ambient light will be reflected upon entering reflective layer 13 and exit the projection screen. This reflected ambient light interferes with the projection light, thereby reducing the contrast of the projected image.

[0150] In order to overcome the above problems, in the related art, the film layer in the projection screen is usually colored, so that the colored film layer can absorb the incident ambient light and reduce the reflection of the ambient light.

[0151] As shown in FIG19 , the adhesive layer 14 can be colored by mixing light-absorbing substances such as dyes and carbon black into the material of the adhesive layer 14, thereby absorbing ambient light when it enters the adhesive layer 14. However, because the colored film layer in the projection screen absorbs light across the entire wavelength range, the projection light L is emitted less efficiently after entering the colored film layer (such as the adhesive layer 14), failing to improve contrast.

[0152] In order to improve the contrast of the projected image, as shown in Figure 20, in some embodiments, the reflective layer can adopt a wavelength-selective reflective layer F. The wavelength-selective reflective layer F can selectively reflect the projection light emitted by the projection device, while greatly reducing the reflectivity of light in other bands. When the projection device is turned off, a black appearance can be achieved, and a bright display can be obtained when the projection device is turned on, thereby significantly improving the contrast of the projected image.

[0153] As shown in Figure 20, projection light L emitted by the projection device enters the projection screen from the side of the surface functional layer 11. Upon entering the lens unit 121, it is reflected by the wavelength-selective reflective layer F on its surface, thereby reflecting toward the viewer. Simultaneously, ambient light C enters the projection screen from the side of the surface functional layer 11. When ambient light C enters the projection screen from the wavelength-selective reflective layer F on the lens unit surface, the wavelength-selective reflective layer F reflects only the projection light and has a low reflectivity for ambient light in other wavelength bands. Therefore, ambient light reflection is significantly reduced, thereby improving the contrast of the projection light.

[0154] Specifically, the wavelength selective reflection layer F uses the principle of a resonant cavity to select the wavelength of light emitted toward the audience, while other wavelengths are restricted in the resonant cavity and cannot be emitted, thereby achieving the effect of selective reflection of the projection light.

[0155] Figure 21 is one of the structural schematic diagrams of the wavelength selective reflection layer provided in an embodiment of the present application; Figure 22 is a second structural schematic diagram of the wavelength selective reflection layer provided in an embodiment of the present application; and Figure 23 is a third structural schematic diagram of the wavelength selective reflection layer provided in an embodiment of the present application.

[0156] As shown in FIG21 and FIG22 , the wavelength selective reflective layer F includes a reflective layer 131 and at least one film layer group z located on the reflective layer 131 . The film layer groups z are stacked and each film layer group z includes a semi-transparent layer 132 and a transparent medium layer 133 .

[0157] The reflective layer 131 reflects light. Located on the side facing away from the viewer, it does not need to transmit light. Therefore, it can be made of a material that is reflective but not translucent. In some embodiments, the reflective layer 131 can be made of materials such as aluminum, an aluminum alloy, silver, or a silver alloy. For example, the reflective layer 131 can be a laminated structure composed of an aluminum alloy such as Al or AlSi, or a silver alloy such as Ag or AgPaCu, without limitation. The reflective layer 131 can also be made using methods such as sputtering and evaporation, without limitation.

[0158] For each film layer group z, the semi-transparent layer 132 is located on the side closest to the surface functional layer 11, and the reflective layer 131 is located on the side of the semi-transparent layer 131 opposite the surface functional layer 11. There is a certain distance between the semi-transparent layer 132 and the reflective layer 131. The transparent dielectric layer 133 is located between the semi-transparent layer 132 and the reflective layer 131. The reflective layer 131, the semi-transparent layer 132, and the transparent dielectric layer 133 form a resonant cavity structure.

[0159] In some embodiments, the wavelength-selective reflective layer F can be configured as a single resonant structure, as shown in FIG21 , where the reflective layer 131 , the semi-transparent layer 132 , and the transparent dielectric layer 133 form a single resonant structure. Alternatively, the wavelength-selective reflective layer F can be configured as a dual resonant structure, as shown in FIG22 , where the reflective layer 131 , the semi-transparent layer 132 , and the transparent dielectric layer 133 form a single resonant structure, and the adjacent semi-transparent layer 132 , the transparent dielectric layer 133 , and the semi-transparent layer 132 form another resonant structure. Similarly, the wavelength-selective reflective layer F can include more than two resonant structures. The more resonant structures the wavelength-selective reflective layer F includes, the more precise its wavelength selectivity is, but the cost also increases accordingly. Therefore, a balance must be struck between performance and cost.

[0160] Specifically, the semi-transparent layer 132 in the wavelength-selective reflective layer F has a semi-transparent, semi-reflective property, allowing projection light to enter the resonant structure when incident on the projection screen. After the projection light oscillates and intensifies within the resonant structure, it can also be emitted from one side of the semi-transparent layer 132. In some embodiments, the semi-transparent layer 132 can be a laminated structure formed of at least one metal selected from the group consisting of Al, Nb, Ag, and Ti, although this is not limited here. The semi-transparent layer 132 can be fabricated using methods such as sputtering and evaporation, which are not limited here.

[0161] The thickness of the transparent dielectric layer 133 determines the cavity length of the resonant structure. The product of the refractive index and thickness of the transparent dielectric layer 133 determines the wavelength of the light emitted from the resonant structure toward the audience and the wavelength that is extinct within the resonant structure. Therefore, when designing the resonant structure, it is necessary to select a dielectric material whose refractive index and thickness product satisfies the conditions for the projection light emitted by the projection device to resonate. In some embodiments, the transparent dielectric layer 133 can be made of materials such as metal oxides, nitrides, or transparent resins. For example, the transparent dielectric layer 133 can be made of metal oxides or nitrides such as TiO2, Nb2O5, ZrO2, Al2O3, ZnO2, SiO2, and can be produced using methods such as reactive sputtering, electron beam (EB) evaporation, and chemical vapor deposition. Alternatively, the transparent dielectric layer 133 can be made of a laminated structure of one or more transparent resins such as PMMA, PC, and PS, and can be produced using wet processing processes such as gravure printing and die coating. The present invention is not limited here.

[0162] In some embodiments, as shown in FIG23 , the wavelength-selective reflector F may further include a substrate 134 located on the side of the semi-transparent layer 132 opposite the transparent dielectric layer 133. Substrate 134 serves as the base of the resonant cavity and provides support. In specific implementations, substrate 134 may be made of materials such as PET, which is not limited herein.

[0163] In an embodiment of the present application, the projection light source can adopt a three-color laser light source device, which can emit red laser, green laser and blue laser. Then, by adjusting the refractive index and thickness of the material of the transparent medium layer, the resonance cavity can simultaneously enhance the reflection of red laser, green laser and blue laser, while at the same time attenuating the reflection of light in other bands, thereby improving the contrast of the projection light.

[0164] Figure 24 shows the reflectivity curves of the wavelength-selective reflective layer provided in an embodiment of the present application for light of different wavelength bands. The dashed lines in Figure 24 represent the peak wavelengths of the three-color laser light emitted by the three-color laser light source device. As can be seen from Figure 24, the wavelength-selective reflective layer can simultaneously exhibit high reflectivity at the wavelengths corresponding to the red, green, and blue lasers emitted by the projection device, while significantly reducing reflectivity at other wavelengths, thereby improving the contrast of the projected light.

[0165] According to simulation tests, when the thickness of the semi-transparent layer 132 is within the range of 2nm to 20nm, the thickness of the reflective layer 131 is greater than 50nm and less than 100nm, and the product of the thickness and refractive index of the transparent medium layer 133 is within the range of 1200 to 1800, the effect is better.

[0166] It's worth noting that the thicknesses of the reflective layer 131, semi-transparent layer 132, and transparent dielectric layer 133 in the wavelength-selective reflector F primarily focus on the thickness of the film layers located on the lens surface x1 of the lens unit 121. This thickness refers to the thickness of the film layers perpendicular to the lens surface x1 of the lens unit 121. This is because when designing the wavelength-selective reflector F, the materials of the various film layers and the cavity length of the resonant cavity are selected and designed based on the incident angle range of ±15° for light incident on the lens surface x1. The thickness and refractive index of the transparent dielectric layer 133 in the wavelength-selective reflector F perpendicular to the lens surface x1 are related to the wavelength of selective reflection, so the coating thickness of the transparent dielectric layer 133 requires precise control.

[0167] Taking the example that the reflective layer 131 , the semi-transparent layer 132 and the transparent medium layer 133 in the wavelength selective reflective layer F are all manufactured by the coating process, the structure of each film layer in the embodiment of the present application is specifically described.

[0168] FIG25 is a schematic diagram of the optical path of the projection light incident on the projection screen provided in an embodiment of the present application.

[0169] As shown in FIG25 , when the projection device is located below the bottom of the projection screen, the incident angles of the projection light emitted by the projection device when it enters different positions on the projection screen are also different. In order to allow more projection light to be concentrated toward the position where it is located, as shown in FIG25 , the inclination angles of the lens surface x1 of each lens unit 121 are different. Taking the Fresnel lens layer 12 shown in FIG25 as an example, as the direction gradually away from the projection device 2 (away from the bottom side of the projection screen), the radius of each lens unit 121 increases successively, and the inclination angle of the lens surface x1 of each lens unit 121 gradually increases, that is, θ3<θ2<θ1. After reasonable design, when the angle of the projection light when it enters the projection screen is 65° to 85°, the incident angle range of the projection light entering the lens surface x1 of different lens units is within the range of 10° to 15°.

[0170] FIG26 is one of the coating schematic diagrams provided in an embodiment of the present application.

[0171] In the related art, as shown in (a) in Figure 26, the coating process is usually a process of depositing a thin film on a flat surface 12', and the film formation direction is perpendicular to the flat surface 12' as shown in the direction of the arrow in Figure 26, that is, the thickness of the thin film 133' at each position on the flat surface 12' perpendicular to the flat surface 12' is basically the same.

[0172] However, as shown in FIG26(b), in the embodiment of the present application, it is necessary to coat the surfaces of the concentric lens units 121. When the same coating process is used to form the light-transmitting dielectric layer 133, the resulting film layer still has a uniform thickness in the film-forming direction. That is, the thickness L of the light-transmitting dielectric layer 133 on each lens unit 121 along a direction perpendicular to the plane of the projection screen (parallel to the film-forming direction in FIG26) is the same. However, the inclination angles of the lens surfaces x1 of each lens unit 121 are different, so the thickness of the light-transmitting dielectric layer 133 along the direction perpendicular to the lens surface x1 on the surfaces of different lens units is different.

[0173] For the sake of convenience, the thickness of the film layer parallel to the film forming direction is referred to as the plane thickness, and the thickness of the film layer perpendicular to the lens surface of the lens unit is referred to as the vertical thickness. According to the relationship shown in Figure 26, the vertical thickness of the light-transmitting medium layer 133 is L×cosθ, where θ is the inclination angle of the lens surface x1 of the lens unit 121. Taking Figure 26 as an example, the vertical thickness of the light-transmitting medium layer 133 on different lens units 121 from the bottom to the top of the projection screen satisfies: L3=L×cosθ3, L2=L×cosθ2, L1=L×cosθ1; and the inclination angle of the lens surface x1 of each lens unit increases with the increase of the radius of the lens unit, that is, θ1>θ2>θ3, then according to the above relationship, it can be seen that: L1 <L2<L3。

[0174] FIG27 is a reflectivity curve of the wavelength shift produced by the wavelength selective reflection layer provided in an embodiment of the present application.

[0175] Comparing FIG. 24 and FIG. 27 , when the transparent dielectric layer 133 is made of Nb 2 O 5 , when the thickness of the transparent dielectric layer 133 increases by 10%, the wavelength selectively reflected by the wavelength selective reflection layer will shift toward the long-wave direction.

[0176] As can be seen, using existing coating processes to produce the wavelength-selective reflective layer F results in the thickness of the light-transmitting medium layer along the lens surface perpendicular to the lens unit decreasing as the radius of the lens unit increases. This can cause the color near the bottom of the projection screen to appear reddish when displaying a completely white image, reducing the screen's color uniformity.

[0177] In view of this, when manufacturing the wavelength selective reflection layer F in the projection screen, the coating equipment is adjusted in the embodiment of the present application, so that the wavelength selective reflection layer F covering the lens surface x1 of each lens unit 121, especially the transparent medium layer 133 in the wavelength selective reflection layer F, has equal thickness perpendicular to the lens surface x1, thereby improving the chromatic uniformity of the projection screen.

[0178] FIG28 is a second schematic diagram of coating provided in an embodiment of the present application.

[0179] When manufacturing the wavelength-selective reflective layer F, and in particular the light-transmitting dielectric layer 133, the thickness of the film can be controlled in the film-forming direction, so that the thickness of the film in the wavelength-selective reflective layer F, perpendicular to the plane where the projection screen is located, increases as the radius of the lens unit increases, thereby ensuring that the thickness of the film on each lens unit 121, perpendicular to the lens surface x1, is equal or approximately equal. Taking FIG. 28 as an example, the thickness of the light-transmitting dielectric layer 133 perpendicular to the lens surface x1 (i.e., the aforementioned vertical thickness) on different lens units 121 from the bottom to the top of the projection screen satisfies: L3 = L2 = L1, while the thickness of the light-transmitting dielectric layer 133 perpendicular to the plane where the projection screen is located (i.e., the aforementioned planar thickness) satisfies: L3'. <L2’<L1’。

[0180] It should be noted that when a wavelength-selective reflector F is used as the reflective layer, the order in which the layers are fabricated in the wavelength-selective reflector F varies depending on the orientation of the Fresnel lens layer 12. In some embodiments, as shown in FIG20 , when the lens units 121 of the Fresnel lens layer 12 are located on the side facing away from the adhesive layer 14, a semi-transmissive layer, a light-transmitting dielectric layer, and a light-reflecting layer are sequentially formed on the lens units 121. In some embodiments, as shown in FIG11 , when the lens units 121 of the Fresnel lens layer 12 are positioned facing the adhesive layer 14, a light-reflecting layer, a light-transmitting dielectric layer, and a semi-transmissive layer are sequentially formed on the lens units 121, in the reverse order of the aforementioned fabrication sequence.

[0181] As shown in Figure 20, projection light L emitted by the projection device enters the projection screen from the surface functional layer 11. Upon entering the lens unit 121, it is reflected by the reflective layer 13 on the lens unit surface, thereby reflecting toward the viewer. Typically, a projection screen including a reflective layer 13 is a reflective screen, and all layers prior to the light entering the reflective layer 13 are translucent.

[0182] In some embodiments, at least one of the light-transmitting layers of the projection screen may contain a subvalent oxide, thereby reducing the transmittance of the light-transmitting layer in the visible light band. In other words, the subvalent oxide has a certain absorption property in the visible light band. This absorbs incident ambient light when displaying a black image, improving the black brightness of the projection screen.

[0183] Suboxides are incomplete oxides. In some embodiments, metal suboxides can be used, and the transmittance to the visible light band can be changed by controlling the oxygen content of the metal suboxides. Metal suboxides are transition products of metals during the oxidation process. Metals are mostly opaque substances. From the metallic state to the fully oxidized oxide state, the transmittance to the visible light band gradually increases, and the absorptivity gradually decreases. Eventually, they are completely oxidized into oxides that are transparent to the visible light band. In the embodiments of the present application, the oxide formed by the fully oxidized metal is called the metal complete oxide, and the oxide formed by the incompletely oxidized metal is called the metal suboxide.

[0184] The following is a detailed introduction to the changes in optical parameters during metal oxidation. Figure 29 is a curve showing the changes in optical parameters of a complete metal oxide provided in an embodiment of the present application; Figure 30 is a curve showing the changes in optical parameters of a low-valent metal oxide provided in an embodiment of the present application.

[0185] Generally speaking, optical parameters include parameters that characterize various aspects of performance. The main parameters to consider in projection screens are the refractive index n and the extinction coefficient k. The extinction coefficient k determines the absorption capacity of incident visible light; a larger extinction coefficient indicates stronger absorption. Comparing Figures 29 and 30, it can be seen that the refractive index n of a complete metal oxide decreases with increasing wavelength and then approaches a constant, while the extinction coefficient k decreases rapidly with increasing wavelength and reaches 0 in the visible light band, indicating no absorption in the visible light band. In contrast, for metal suboxides, the refractive index n decreases and then increases with increasing wavelength, while the extinction coefficient k decreases, then increases, and then decreases again with increasing wavelength. The extinction coefficient k is above 0 in the visible light band, indicating absorption in the visible light band. Therefore, by adding a metal suboxide to at least one of the translucent film layers in a projection screen, the film layer can be made both translucent and absorbent in the visible light band.

[0186] In practice, metal suboxides can be produced using a reactive sputtering process with plasma luminescence control. Within the sputtering chamber, the sputtering source is metal. In addition to discharge gases such as argon, reactive gases such as oxygen are also used. By controlling the flow rate of the reactive gases, the plasma luminescence intensity is adjusted to form the metal suboxides. A transition state exists during the transition from the metallic state to the fully oxidized metal oxide, and metal suboxides can form within this transition zone.

[0187] Specifically, Figure 31 shows a curve showing the oxidation number as a function of the reactive gas flow rate in a plasma-luminescence-controlled reactive sputtering process according to an embodiment of the present application; Figure 32 shows a curve showing the oxygen partial pressure as a function of the reactive gas flow rate in a plasma-luminescence-controlled reactive sputtering process according to an embodiment of the present application; and Figure 33 shows a curve showing the extinction coefficient as a function of the reactive gas flow rate in a plasma-luminescence-controlled reactive sputtering process according to an embodiment of the present application. The sputtering source is a metal, and the reactive gas is oxygen. During the sputtering process, the metal is gradually oxidized, gradually transforming from a metallic state to a fully metal oxide state. The solid circled areas in Figures 31 to 33 represent the metal suboxide state, and the dashed circled areas represent the metal fully oxide state.

[0188] As shown in Figures 31 and 32, as the reactive gas flow rate gradually increases, the main component of the substance formed in the metal zone is metal, and the oxidation number and oxygen partial pressure tend to increase slowly; when it reaches the transition zone, the metal is partially oxidized, and the main component is metal low-valent oxide, and the oxidation number and oxygen partial pressure increase significantly; and when it reaches the oxide zone, the metal is completely oxidized into metal complete oxide, and the oxidation number and oxygen partial pressure show a trend of slowly increasing. After the reactive gas flow rate increases to a certain level, the oxidation number and oxygen partial pressure tend to stabilize.

[0189] As shown in Figure 33, as the reactive gas flow rate gradually increases, the main component of the substance formed in the metal zone is still metal, so the extinction coefficient is large, the light absorption is strong and the light transmittance is poor; as the reactive gas flow rate gradually increases, the metal is gradually oxidized. When the metal is oxidized into a metal low-valent oxide in the transition zone, its extinction coefficient is greatly reduced, but it still has a certain light absorption and the light transmittance increases; as the reactive gas flow rate increases to a certain extent, the metal is completely oxidized to form a metal complete oxide. At this time, the extinction coefficient is reduced to the minimum value and it no longer has light absorption.

[0190] It can be seen from this that by controlling the oxygen content of metal suboxides, their extinction coefficients can be changed, thereby making the metal suboxides have different degrees of absorption of visible light.

[0191] In order to improve the contrast of the projected image, the reflective layer 13 can adopt a wavelength selective reflective layer F. Based on the above analysis, low-valent oxides can be used in the wavelength selective reflective layer F to make it have both wavelength selective reflectivity and absorption of incident light, thereby improving the performance of the projection screen.

[0192] As described above, the product of the refractive index and thickness of the light-transmitting dielectric layer 133 in the wavelength-selective reflector F determines the wavelength selectively reflected by the light-transmitting dielectric layer. In some embodiments, the light-transmitting dielectric layer 133 may be made of a complete metal oxide, such as TiO2, Nb2O5, ZrO2, Al2O3, ZnO2, or SiO2. However, these complete metal oxides are transparent to light in the visible light band. To ensure that the wavelength-selective reflector F has both wavelength-selective reflectivity and absorptivity, the light-transmitting dielectric layer 133 may contain a suboxide. As described above, the light-transmitting dielectric layer 133 may be made of a metal suboxide, or a metal suboxide may be added to the material of the light-transmitting dielectric layer 133. By controlling the oxygen content of the metal suboxide, its transparency can be reduced to a certain extent.

[0193] In this way, the wavelength selective reflection layer F can have both wavelength selective reflectivity and a certain light absorption property in the visible light band, which can play a role in shielding ambient light. There is no need to set a separate light absorption layer in the projection screen, which simplifies the structure of the projection screen and reduces production costs.

[0194] In some embodiments, the material of the light-transmitting medium layer 133 in the wavelength-selective reflective layer F may be entirely low-valent oxides.

[0195] In some embodiments, the material of the light-transmitting medium layer 133 in the wavelength-selective reflective layer F may include a subvalent oxide and a complete oxide. For example, the subvalent oxide and the complete oxide may be layered.

[0196] In some embodiments, the light-transmitting dielectric layer 133 may include a first dielectric layer and a second dielectric layer stacked together. The first dielectric layer may be a subvalent oxide, and the second dielectric layer may be a complete oxide. Alternatively, the first dielectric layer may be a complete oxide, and the second dielectric layer may be a subvalent oxide. The order in which the subvalent oxide and the complete oxide are disposed is not limited.

[0197] Each film layer in the wavelength-selective reflective layer F can be fabricated using a sputtering process. During sputtering to form the light-transmitting dielectric layer 133, the flow rate of the reactive gas, namely oxygen, is controlled to induce varying degrees of oxidation of the metal. Partial oxidation forms a metal suboxide, while complete oxidation forms a metal oxide. The absorption capacity of the film layer formed by reactive sputtering decreases with increasing oxygen content. Therefore, precise control of the reactive gas flow rate is necessary to achieve appropriate light absorption in the light-transmitting dielectric layer 133.

[0198] In a specific implementation, the metal suboxide in the light-transmitting dielectric layer can be one of Nb2O5-x, TiO2-y, or Ta2O5-z, where 0<x<5, 0<y<2, and 0<z<5. x, y, and z can be integers or decimals within the aforementioned ranges, and are not limited thereto. In addition to the aforementioned materials, other metal suboxides can also be used, and are not listed here.

[0199] FIG34 is a curve showing the change of film forming rate with the flow rate of reactive gas in the reactive sputtering process controlled by plasma luminescence provided in an embodiment of the present application.

[0200] As shown in Figure 34, as the reactive gas flow rate gradually increases, the main component of the film layer in the metal area is still metal, so the film formation speed is faster; as the reactive gas flow rate gradually increases, the metal is gradually oxidized, and the film formation speed also decreases accordingly; as the reactive gas flow rate increases to a certain level, the metal is completely oxidized to form a complete metal oxide, and the film formation speed further decreases.

[0201] As can be seen from Figure 34, the film formation speed of metal suboxides is faster than that of metal complete oxides. Therefore, if metal suboxides are used as the transparent medium layer of the resonant structure, productivity can be improved, which is conducive to reducing costs.

[0202] Based on the same concept, an embodiment of the present application further provides a projection system, as shown in FIG1 , the projection system includes: a projection device 2 and a projection screen 1 located on the light-emitting side of the projection device 2 .

[0203] FIG35 is a schematic diagram of the structure of the projection device provided in an embodiment of the present application.

[0204] As shown in Figure 35, the projection device includes: a light source device 21, an illumination optical path 22, a light modulation component 23, and a projection lens 24. The illumination optical path 22 is located on the light exit side of the light source device 21, the light modulation component 23 is located on the light exit side of the illumination optical path 22, and the projection lens 24 is located on the light exit side of the light modulation component 23.

[0205] The light source device 21 can be a laser light source device. The laser light source device can be a monochromatic laser, a laser that can emit multiple colors of laser light, or multiple lasers that emit different colors of laser light. When the laser light source device uses a monochromatic laser, the laser display device also needs to be provided with a color wheel, which is used for color conversion. The monochromatic laser combined with the color wheel can achieve the purpose of emitting primary color lights of different colors in a time sequence. When the laser light source device uses a laser that can emit multiple colors of laser light, it is necessary to control the laser light source to emit different colors of laser light as the primary color light in a time sequence.

[0206] In the embodiments of the present application, the light source device may employ a three-color laser light source device. This three-color laser light source device may be a laser that emits three primary colors of laser light, such as an MCL laser. Alternatively, it may include a red laser, a green laser, and a blue laser that emit three primary colors of laser light, respectively. Using a three-color laser light source device improves the color gamut of the projected image, providing better color expression and accurately reproducing the input image.

[0207] The illumination optical path 22 is located on the light-emitting side of the light source device 21. The illumination optical path 22 collimates the light emitted by the light source device 21 and allows the light emitted by the light source device 21 to be incident on the light modulation component 23 at a suitable angle. The illumination optical path 22 can include multiple lenses or lens groups, which are not limited here.

[0208] The light modulator 23 is used to modulate the incident light. In some embodiments, the light modulator 23 can be a digital micromirror device (DMD). The light modulator 23 receives the incident light after total reflection by the total reflection prism P, modulates the incident light, and reflects the modulated light. After passing through the illumination optical path 22, the light beam meets the illumination size and incident angle required by the DMD. The DMD surface includes many tiny mirrors, each of which can be individually driven for deflection. By controlling the deflection angle of the DMD, the brightness of the light incident on the projection lens 24 is controlled.

[0209] The projection lens 24 is used to form an image of the output light of the light modulation component 23 . After the image is formed by the projection lens 24 , the image is projected.

[0210] In the embodiment of the present application, the projection device 2 can be an ultra-short-throw projection device, that is, the projection lens 24 in the projection device is an ultra-short-throw projection lens. The use of an ultra-short-throw projection device can greatly shorten the distance between the projection device 2 and the projection screen 1, thereby shortening the projection distance and achieving large-scale image display.

[0211] The projection screen is located on the light-emitting side of the projection lens in the projection device. It comprises a surface functional layer, a Fresnel lens layer, and a reflective layer. The projection screen can be any of the aforementioned projection screens, which can absorb incoming ambient light, improve the black level of the projection screen, selectively reflect incoming projection light while absorbing light in other wavelengths to enhance the contrast of the projected image, and improve the gain uniformity of the projection screen.

[0212] Another aspect of an embodiment of the present application provides a method for manufacturing a projection screen. FIG36 is one of the flow charts of the method for manufacturing a projection screen provided in an embodiment of the present application.

[0213] As shown in FIG36 , the method for manufacturing a projection screen includes:

[0214] S10, manufacturing a Fresnel lens layer;

[0215] S20, forming a wavelength selective reflection layer on the surface of the lens unit;

[0216] S30, forming a surface functional layer on one surface of the Fresnel lens layer with the wavelength selective reflection layer.

[0217] In some embodiments, the Fresnel lens layer can be formed using a UV molding process. A UV-curable resin is applied to a mold with a lens unit shape on its surface. A substrate is then pressed against the UV-curable resin at a set pressure. UV radiation is then applied to the substrate from one side to cure the UV-curable resin. As the UV-curable resin cures, it adheres tightly to the substrate, transferring the shape of the lens units from the mold to the substrate, forming the Fresnel lens layer.

[0218] In some embodiments, the integrally formed Fresnel lens layer may be manufactured by thermoforming, where a heated mold having a Fresnel structure is used to thermoform a thermoplastic material layer, thereby forming the Fresnel lens layer.

[0219] The Fresnel lens layer fabricated using the above method has a plurality of lens units on one side of its surface. Each lens unit can be arranged in concentric circles, extending radially in sequence. Each lens unit comprises a lens surface and a non-lens surface connected to each other. The lens surfaces are tilted at an angle such that projection light incident on the reflective layer on the lens surface is reflected toward the viewer.

[0220] The wavelength-selective reflective layer can be produced using a coating process such as sputtering or evaporation. Depending on the structure of the projection screen, the order in which the various film layers in the wavelength-selective reflective layer are produced is also different. When the lens units of the Fresnel lens layer are arranged facing the surface functional layer, the order in which the wavelength-selective reflective layer is produced is as follows: forming a reflective layer on the surface of the lens units of the Fresnel lens layer; forming a translucent dielectric layer on the surface of the reflective layer; and forming a semi-translucent layer on the surface of the translucent dielectric layer. When the lens units of the Fresnel lens layer are arranged away from the surface functional layer, the order in which the wavelength-selective reflective layer is produced is as follows: forming a semi-translucent layer on the surface of the lens units of the Fresnel lens layer; forming a translucent dielectric layer on the surface of the semi-translucent layer; and forming a reflective layer on the surface of the translucent dielectric layer.

[0221] When a sputtering process is used to produce a semi-transparent layer, a reflective layer and a transparent medium layer, especially when producing a transparent medium layer, the embodiment of the present application adjusts the sputtering equipment so that the thickness of the film layer finally formed on the lens surface of the lens unit along the direction perpendicular to the plane where the projection screen is located increases with the increase of the radius of each concentric lens unit, and the thickness of the film layer on the lens surface of each lens unit along the direction perpendicular to the lens surface can be equal or approximately equal.

[0222] Figure 37 is a structural schematic diagram of the film-forming cathode part of the sputtering equipment in the related art, Figure 38 is a structural schematic diagram of the film-forming cathode part of the sputtering equipment provided in an embodiment of the present application, and Figure 39 is a schematic diagram of the sputtering process provided in an embodiment of the present application.

[0223] 37 and 38 , (a) represents the top view structure of the sputtering device, (b) represents the side view structure of the sputtering device, and (c) represents the film thickness at different positions.

[0224] As shown in (a) and (b) in Figure 37, in the related art, the plane and cross-section of the sputtering source N in the sputtering equipment are uniform structures, and the substrate to be coated is placed above the sputtering source N. As shown in (c) in Figure 37, the thickness of the film layer formed at different positions on the substrate is also equal.

[0225] In order to adjust the thickness of the film layer, an embodiment of the present application, as shown in Figure 38, is provided above the sputtering source N with a correction plate D, wherein the correction plate D includes a plurality of sub-correction plate pairs a, each of which includes two sub-correction plates, and a gap of a set distance is provided between the two sub-correction plates; each sub-correction plate pair a is arranged along the second direction y.

[0226] As shown in FIG39 , a flexible material can be used when manufacturing the Fresnel lens layer, thereby allowing the formed Fresnel lens layer to be rolled. When the wavelength selective reflective layer is formed by sputtering, the Fresnel lens layer can be rolled so that the lens units 121 of the Fresnel lens layer 12 face the sputtering source N. During the sputtering process, the Fresnel lens layer 12 is rolled so that the Fresnel structure layer 12 moves above the sputtering source N along the first direction x.

[0227] As shown in Figure 39, the first direction x and the second direction y are perpendicular to each other. The second direction y is perpendicular to a first side of the projection screen. This first side can be the side where the centers of the concentric lens units are close. When the projection device is positioned at the bottom of the projection screen, the second direction y is perpendicular to the bottom side of the projection screen. In the embodiment of the present application, the sub-correction plate pairs a are arranged along the second direction, and the gaps between the sub-correction plate pairs a increase with the radius of the concentric lens units. The sputtering source deposits a greater film thickness at locations where the gaps between the sub-correction plate pairs a are larger, and a smaller film thickness at locations where the gaps between the sub-correction plate pairs a are smaller. This allows the thickness of the light-transmitting dielectric layer formed on the lens unit surfaces, perpendicular to the plane of the projection screen, to gradually increase from the bottom to the top of the projection screen. Consequently, the thickness of the light-transmitting dielectric layer on the reflective surface of each lens unit, perpendicular to the reflective surface, can be equal or approximately equal, thereby improving the chromatic uniformity of the projection screen.

[0228] In some embodiments, the gap width of each sub-correcting plate pair a can be set according to the tilt angle of the lens surface of the corresponding lens unit. However, the width of a lens unit typically ranges from tens to hundreds of microns, making it difficult to adjust the width of the sub-correcting plate pair a to such dimensions. In embodiments of the present application, a sub-correcting plate pair a can be configured to correspond to multiple lens units, and the gap width of the sub-correcting plate pair a can be configured according to the average tilt angle of the lens surfaces of the corresponding multiple lens units.

[0229] Finally, a surface functional layer is formed on one side of the Fresnel lens layer having the wavelength-selective reflective layer. The surface functional layer can have effects such as expanding the viewing angle, preventing ambient light reflection, and preventing ceiling glare. The surface functional layer can be located on different sides of the Fresnel lens layer.

[0230] In some embodiments, the surface functional layer can be located on the side of the Fresnel lens layer away from the lens unit. In this case, the surface functional layer may include a substrate and a diffusion layer formed on the surface of the substrate. The projection screen is formed by bonding the substrate of the surface functional layer to the Fresnel lens layer. Alternatively, a substrate containing a diffusion material can be directly used as the surface functional layer and bonded to the Fresnel lens layer to form a projection screen. Alternatively, the surface of the substrate can be directly sandblasted to form the surface functional layer, and then the substrate and the Fresnel lens layer are bonded to form the projection screen. This is not limited here.

[0231] In some embodiments, the surface functional layer may also be located on the wavelength selective reflection layer on the surface of the lens unit. In this case, the surface functional layer may be manufactured by directly performing sandblasting on the wavelength selective reflection layer, which is not limited here.

[0232] As described above, when the projection system is used in scenarios such as laser television, the projection device can be an ultra-short-throw projection device. As shown in FIG40 , in a projection screen used with an ultra-short-throw projection device, the center O of the lens unit 121 is typically not located within the projection screen, but rather in an area outside the projection screen. The side of the projection screen closest to the center O is typically the bottom side of the screen, and the radius of each lens unit 121 gradually increases as it moves away from the bottom side. If the side of the projection screen facing the audience is called the front side, and the side facing away from the audience is called the back side, then in some embodiments, each lens unit 121 is located on the back side of the projection screen. Placing each lens structure on the back side of the projection screen can reduce the risk of contamination and damage caused by user contact and ensure the long-term reliability of the Fresnel lens layer.

[0233] The following describes the structure and manufacturing method of a projection screen used with an ultra-short-throw projection device as an example. However, the projection screen manufacturing method provided in the embodiments of the present application is not limited to manufacturing screens for ultra-short-throw projection devices. The manufacturing method can also be used to manufacture screens for different types of projection devices, such as short-throw and long-throw projection devices. During implementation, only relevant parameters need to be adaptively adjusted.

[0234] FIG41 is a schematic diagram of the cross-sectional structure along the A-A' direction in FIG2 . The A-A' direction coincides with the vertical axis of symmetry of the projection screen. The projection screen provided in the embodiment of the present application is an axisymmetric structure, with its axis of symmetry parallel to the vertical direction. When in use, the projection screen is typically mounted on a wall or hung high, and the bottom edge of the projection screen is parallel to the horizontal direction. In this case, the vertical direction is a direction perpendicular to the horizontal direction, and the extension line of the vertical axis of symmetry of the projection screen passes through the center O of the lens structure.

[0235] As shown in FIG41 , the projection screen is provided with a Fresnel lens layer 12. The surface of the Fresnel lens layer 12 facing away from the projection device includes multiple lens units 121. In a cross-section along the A-A' line in FIG10 , each lens unit 121 is shaped like a triangle and comprises a lens surface x1 and a non-lens surface x2 connected to each other. The lens surface x1 is tilted relative to the plane of the projection screen, and the non-lens surface x2 is used to connect the lens surface x1. The tilt angle of the lens surface x1 of each lens unit 121 is designed based on the incident angle of the projection light. This tilt angle ensures that the projection light L is reflected toward the viewer upon entering the reflective layer 13 on the lens surface x1. This allows more projection light to be reflected toward the viewer while reducing the amount of ambient light reflected toward the viewer, thereby improving the brightness and contrast of the projected image.

[0236] When forming a reflective layer on the surface of a Fresnel lens, the original design intended that the reflective layer be formed only on the lens surface x1 of the lens unit, and not on the non-lens surface x2. Reflective layers are typically produced using evaporation or sputtering processes. However, current processes for producing reflective layers not only form on the lens surface x1 of the lens unit, but also on the non-lens surface x2. This results in light being reflected from the non-lens surface x2 as well, which is inconsistent with the original design.

[0237] In view of this, an embodiment of the present application provides a method for manufacturing a projection screen. Figure 42 is the second flow chart of the method for manufacturing a projection screen provided in an embodiment of the present application.

[0238] As shown in FIG42 , the method for manufacturing a projection screen includes:

[0239] S10, manufacturing a Fresnel lens layer;

[0240] S20, setting an evaporation source at a set position of the Fresnel lens layer to form a reflective layer on the lens surfaces of the plurality of lens units;

[0241] S30, forming a surface functional layer on a side of the Fresnel lens layer facing away from the reflective layer.

[0242] This embodiment of the present application uses an evaporation process to produce a reflective layer as an example. In addition to evaporation, sputtering or similar processes can also be used to produce the reflective layer. The reflective layer can be made of a reflective metal material such as aluminum, silver, or titanium. Furthermore, the reflective layer can also have a multi-layer structure to selectively reflect incident light, thereby further improving the contrast of the projected image.

[0243] By improving the structure and position of the evaporation source in the embodiment of the present application, the reflective layer can be formed only on the lens surface of the lens unit, avoiding the reflective layer from being formed on the non-lens surface of the lens unit. The following is a detailed description of the production process of the projection screen.

[0244] The Fresnel lens layer 12 may include a substrate and lens units 121 located on the substrate, wherein the lens units 121 may be manufactured by using a mold having a Fresnel lens and a UV molding process using an ultraviolet curable resin.

[0245] Before manufacturing the reflective layer 13 on the surface of the lens unit 121 , the structure and location of the evaporation source need to be designed, and the design can be in various forms.

[0246] Figure 43 is a schematic diagram of the cross-sectional structure of the positional relationship between the evaporation source and the Fresnel lens layer provided in an embodiment of the present application; Figure 44 is one of the schematic diagrams of the planar structure of the positional relationship between the evaporation source and the Fresnel lens layer provided in an embodiment of the present application; Figure 45 is a second schematic diagram of the planar structure of the positional relationship between the evaporation source and the Fresnel lens layer provided in an embodiment of the present application; and Figure 46 is a schematic diagram of the cross-sectional structure along the I-I' direction in Figure 44.

[0247] As shown in FIG43 , the evaporation source W is disposed on a side of the Fresnel lens layer 12 having the lens unit 121 , and there is a certain distance between the evaporation source W and the lens unit 121 . The evaporation source radiates the evaporation material isotropically when in operation.

[0248] In some embodiments, as shown in Figures 44 and 45 , at least one arc-shaped evaporation source W can be used to form the reflective layer. As shown in Figure 44 , there can be one evaporation source W, which is relatively large and shaped like a circular arc. Alternatively, as shown in Figure 45 , there can be multiple evaporation sources W, which are relatively small and arranged in an arc.

[0249] The evaporation source will isotropically radiate the evaporation material when evaporating the reflective layer. The setting position of the evaporation source W set in an arc shape satisfies the orthographic projection of the center of the evaporation source W on the plane where the projection screen is located and the center of the lens unit 121, so that the evaporation material can be relatively evenly formed on the lens unit 121.

[0250] In order to prevent the evaporation source W from forming the evaporation material on the non-lens surface x2 of the lens unit 121, when the radius of the evaporation source W arranged in an arc shape is greater than the radius of any lens unit 121 in the Fresnel lens layer, only the evaporation material emitted from the evaporation source W toward the side of the center O will be incident on the lens surface x1 of the lens unit 121, thereby preventing the evaporation material from being incident on the non-lens surface x2 of the lens unit 121.

[0251] Figures 44 and 45 illustrate the example of the evaporation source W being arranged in the form of a circular arc. In a specific implementation, the evaporation source W can also be arranged in multiple circular arcs. In this case, multiple evaporation sources are required. In some embodiments, the size of the evaporation source is relatively large, and the shape of each evaporation source is a circular arc. Multiple evaporation sources can be arranged in multiple concentric circular arcs; in some embodiments, the size of each evaporation source is relatively small, and these evaporation sources are arranged into multiple circular arcs, and each circular arc is formed by the arrangement of multiple evaporation sources.

[0252] When the evaporation source is arranged in multiple arcs, the arcs can be arranged concentrically, and the radius of each arc needs to be larger than the radius of any lens unit 121 in the Fresnel lens layer. Based on this design concept, the minimum radius of the evaporation source arranged in an arc shape can be determined.

[0253] Specifically, as shown in FIG46 , in the order of the radius of each lens unit 121 from small to large, the inclination angle of the non-lens surface of the m-th lens unit relative to the normal line tm is α m The inclination angle of the non-lens surface of the nth lens unit relative to the normal line tn is α n In the cross section shown in FIG46 , the angle of inclination of the line connecting the innermost point P of the evaporation source and the vertex of the m-th lens unit with respect to the normal line tm is θ m The inclination angle of the line connecting the evaporation source W and the vertex of the nth lens unit relative to the normal line tn is θ n The vertical distance from the plane of the innermost point P of the evaporation source to the vertex of the lens unit 121 is h, and the distance from the innermost point P of the evaporation source to the normal tm passing through the vertex of the m-th lens unit is S m The distance from the innermost point P of the evaporation source to the normal line tn passing through the vertex of the nth lens unit is S n .

[0254] Among them, the normal t m , t n The normal line t is the normal to the plane of the projection screen. The normal line t claimed in the embodiments of this application is perpendicular to the plane of the projection screen. The Fresnel lens layer 12 shown in FIG46 includes a substrate. The plane of the projection screen can be parallel to the plane of the substrate of the Fresnel lens layer 12. Therefore, the plane of the projection screen claimed in the embodiments of this application can refer to the plane of the Fresnel lens layer 12 in FIG46. Hereinafter, the normal line to the plane of the projection screen is referred to as simply the normal line.

[0255] As shown in FIG44 , from a planar structural perspective, the evaporation source is arranged in an arc shape, and the orthographic projection of the center of the arc-shaped evaporation source onto the plane of the projection screen coincides with the center of the arc-shaped lens unit. The radius of the arc-shaped evaporation source is greater than the radius of all the circular lens units. The evaporation source W typically radiates the evaporation material isotropically when emitting the evaporation material. When the side of the evaporation source W emitting the evaporation material is positioned opposite the side of the Fresnel lens layer 12 having the lens unit 121, as shown in FIG44 , only the evaporation material emitted from the innermost periphery of the evaporation source W can be incident on the lens unit 121. Therefore, in a radial cross-section, as shown in FIG46 , the innermost point P of the evaporation source refers to the point in the cross-section where the evaporation source is closest to the center O, i.e., the rightmost point of the evaporation source in FIG46 . As can be seen from Figure 46, in the cross-section along any radial direction, the inclination angle of the evaporated material emitted from the innermost point P of the evaporation source when it is incident on the vertex of the lens unit relative to the normal is usually smaller than the inclination angle of the evaporated material emitted from other positions of the evaporation source when it is incident on the vertex of the same lens unit relative to the normal. Therefore, the minimum inclination angle formed by the line connecting the innermost point P of the evaporation source and the vertex of the lens unit 121 is taken into consideration.

[0256] As shown in FIG. 46 , the vertex of the lens unit 121 refers to the intersection of the lens surface x1 and the non-lens surface x2 of the lens unit 121 on the side closer to the vapor deposition source W in any cross section.

[0257] According to the trigonometric function relationship:

[0258] In order to prevent the vapor deposition material emitted from the vapor deposition source W from being formed on the non-lens surface x2 of the Fresnel lens, the m-th lens unit needs to satisfy α m <θ m , for the nth lens unit, α needs to be satisfied n <θ n Then, when the evaporation source W satisfies the above relationship for each lens unit 121 , the minimum radius R that the evaporation source W arranged in an arc shape should satisfy can be found.

[0259] FIG46 illustrates an arc-shaped evaporation source, and the cross section shown in FIG46 is a cross section along the symmetry axis II' of the projection screen. When more arc-shaped evaporation sources are used or the evaporation sources are arranged into multiple concentric arcs, the cross section of each arc along any radial direction satisfies the following conditions:

[0260] Among them, α i represents the inclination angle of the non-lens surface of the i-th lens unit 121 relative to the normal of the plane where the projection screen is located in a cross section along any radial direction of the Fresnel lens layer, θi S represents the inclination angle of the line connecting the innermost point of the vapor deposition source and the vertex of the i-th lens unit 121 with respect to the normal line in the cross section. i represents the distance from the innermost point of the vapor deposition source in the cross section to the normal line passing through the vertex of the i-th lens unit, and h represents the distance from the plane including the innermost point of the vapor deposition source to the vertex of the lens unit 121 .

[0261] The definitions of the normal, the innermost point of the evaporation source in the cross section, and the vertex of the lens unit can be referred to in the above embodiment and will not be repeated here. Referring to Figure 46, the plane including the innermost point P of the evaporation source is the plane passing through point P and parallel to the plane of the projection screen.

[0262] The position of the evaporation source satisfies the requirement that the inclination angle of the line connecting the vertices of any lens unit with respect to the normal of the plane on which the projection screen is located is greater than the inclination angle of the line connecting the vertices of the lens unit with respect to the non-lens surface of the lens unit. Thus, when the evaporation source radiates the evaporation material toward the Fresnel lens layer, the evaporation material can be prevented from being incident on the non-lens surface of each lens unit.

[0263] In some embodiments, the tilt angle of the lens surface x1 of each lens unit 121 in the Fresnel lens layer 12 relative to the plane of the projection screen, and the tilt angle of the non-lens surface x2 of each lens unit 121 relative to the normal of the plane of the projection screen, may vary. Therefore, the evaporation source needs to be set according to actual conditions.

[0264] Specifically, when a projection screen is used in an ultra-short-throw projection system, the projection device is typically located below the projection screen, emitting projection light diagonally upward onto the projection screen. If the projection light is to be reflected toward the viewer, the inclination angle of the lens surface x1 of each lens unit 121 in the Fresnel lens layer 12 relative to the plane of the projection screen satisfies the following conditions: the inclination angle of the lens surface x1 increases with the radius of the lens unit. As shown in Figures 43 and 46, in a projection screen used in an ultra-short-throw projection system, the center O of the Fresnel lens is located outside the projection screen. In the cross-sectional structural diagrams shown in Figures 43 and 46, the farther from the center O, the greater the inclination angle of the lens surface x1 of the lens unit 121 relative to the plane of the projection screen.

[0265] For the non-lens surface x2 of each lens unit 121 , its inclination angle relative to the normal line of the plane where the projection screen is located may change along with the lens surface x1 or may remain unchanged.

[0266] In some embodiments, as shown in FIG43 , the non-lens surface x2 of each lens unit 121 has the same inclination angle relative to the normal line t of the plane where the projection screen is located. For example, the non-lens surface x1 of each lens unit 121 is perpendicular to the plane where the projection screen is located, that is, α in the above formula (1) is i = 0. Then the position of the arc-shaped evaporation source W satisfies that in any cross section along the radial direction, the inclination angle between the innermost point of the evaporation source W and the vertex of any lens unit 121 in the cross section relative to the normal of the plane where the projection screen is located is greater than 0, that is, θ in the above formula (1) is i >0.

[0267] In some embodiments, as shown in FIG46 , the inclination angle of the non-lens surface x2 of each lens unit 121 relative to the normal line t of the plane where the projection screen is located increases as the radius of the lens unit 121 increases, that is, in the cross-sectional view α shown in FIG46 , n >α m When the evaporation source W is set for this situation, the maximum value of the inclination angles of the non-lens surface x2 in the Fresnel lens layer 12 relative to the normal of the plane where the projection screen is located is the inclination angle of the non-lens surface of the lens unit with the largest radius. Therefore, the evaporation source W only needs to satisfy the requirement that, in a cross section along any radial direction of the Fresnel lens layer, the inclination angle of the line connecting the innermost point of the evaporation source and the vertex of the lens unit with the largest radius relative to the normal is greater than the inclination angle of the non-lens surface of the lens unit with the largest radius relative to the normal. The above-mentioned normals are all normals to the plane where the projection screen is located.

[0268] In a specific implementation, the distance between the evaporation source and the Fresnel lens layer can be 100 mm to 1000 mm, the width of the arc-shaped evaporation source can be 20 mm to 300 mm, and the spacing between two adjacent circular evaporation sources can be within 300 mm. For example, the vertical distance between the evaporation source and the Fresnel lens layer can be 300 mm, the width of the arc-shaped evaporation source can be 100 mm, and the spacing between two adjacent circular evaporation sources can be 20 mm.

[0269] Figure 47 is one of the cross-sectional structural schematic diagrams of the positional relationship between the evaporation source, baffle and Fresnel lens layer provided in an embodiment of the present application; Figure 48 is a planar structural schematic diagram of the positional relationship between the baffle and Fresnel lens layer provided in an embodiment of the present application; Figure 49 is a second cross-sectional structural schematic diagram of the positional relationship between the evaporation source, baffle and Fresnel lens layer provided in an embodiment of the present application; Figure 50 is one of the planar structural schematic diagrams of the positional relationship between the evaporation source, baffle and Fresnel lens layer provided in an embodiment of the present application; Figure 51 is a second planar structural schematic diagram of the positional relationship between the evaporation source, baffle and Fresnel lens layer provided in an embodiment of the present application.

[0270] In some embodiments, as shown in FIG47 , a vapor deposition source W may be provided on a side of the Fresnel lens layer 12 having a plurality of lens units 121, so that a set distance exists between the vapor deposition source W and the plurality of lens units 121; and a plurality of spaced baffles D' may be provided between the vapor deposition source W and the plurality of lens units 121, so that the baffles D' block the vapor deposition material emitted from the vapor deposition source W from being formed on the non-lens surface x2 of the lens unit 121.

[0271] Specifically, a plurality of baffles D' are provided between the evaporation source W and the Fresnel lens layer 12 to prevent the evaporation source W from emitting the evaporation material onto the non-lens surface x2 of the lens unit 121. Since the lens surface and the non-lens surface of the lens unit 121 may have different inclination angles, the baffles D' generally need to be set at an angle, and the inclination angles of the baffles at different positions may be different. The inclination angle of each baffle needs to be set based on the standard that the evaporation material emitted by the evaporation source near it is blocked by the baffle D' and is not formed on the non-lens surface x of the lens unit 121 at the corresponding position. In some embodiments, the width of the lens unit 121 is on the order of microns, and the spacing between the baffles D' can be tens of millimeters or more. The solution of the evaporation source W and the baffle D' cooperating with each other can prevent the distance between the evaporation source W and the Fresnel lens layer 12 from being too large, thereby avoiding the uneven evaporation caused by the long distance between the evaporation source W and the distal lens unit.

[0272] The evaporation source W can be arranged in an arc shape. Accordingly, the baffle D' is shaped like a portion of a conical surface. Figure 48 shows the planar structure of baffle D', where the overall outline of baffle D' is an arc. From a three-dimensional perspective, the orthographic projection of the vertex of the conical surface of baffle D' onto the plane of the projection screen coincides with the center of the lens unit 121.

[0273] In some embodiments, as shown in FIG. 47 , the evaporation source W may have a relatively large width. In this case, only one evaporation source W is required, and the evaporation source W may correspond to multiple baffles D′, thereby reducing the number of evaporation sources W used.

[0274] In some embodiments, as shown in FIG49 , the evaporation source W may have a relatively small width and be multiple in number. In this case, a baffle D' may be provided between each two adjacent evaporation sources W, thereby enabling a more refined design of the evaporation source and the baffle. In some embodiments, as shown in FIG50 and FIG51 , the evaporation source W may be provided in the form of multiple arcs. Referring to FIG50 , the number of evaporation sources W may be multiple, each evaporation source W being in the shape of an arc, and each arc-shaped evaporation source W may be concentrically arranged. Alternatively, referring to FIG51 , the number of evaporation sources W may be multiple, and each evaporation source W may be discretely arranged, and these evaporation sources W may be dispersedly arranged into multiple concentrically arranged arcs, each arc being formed by an arrangement of multiple evaporation sources.

[0275] In order to prevent the vapor deposition material from being formed on the non-lens surface x2 of each lens unit 121 , the baffle D′ has a certain tilt angle. The tilt angle satisfied by the baffle will be described in detail below.

[0276] Figure 52 is a third schematic diagram of a cross-sectional structure illustrating the positional relationship between the evaporation source, baffle, and Fresnel lens layer according to an embodiment of the present application. Figure 52 shows a cross-sectional structure along the line II' in Figure 50. As shown in Figure 52, the non-lens surface x2 of the lens unit 121 is tilted at an angle α relative to the normal t of the plane of the projection screen. In the cross-section shown in Figure 52, the line connecting the innermost point P of the evaporation source and its corresponding edge of the baffle D' on the side closest to the Fresnel lens layer is tilted at an angle θ relative to the normal t. In the cross-section shown in Figure 52, the perpendicular distance from the innermost point P of the evaporation source to the normal passing through the edge of the baffle D' on the side closest to the Fresnel lens layer is S1, and the distance from the plane including the innermost point of the evaporation source to the edge of the baffle D' on the side closest to the Fresnel lens layer is h1.

[0277] The definitions of the normal line, the innermost point of the evaporation source in the cross section, and the plane including the innermost point of the evaporation source may refer to the above embodiments and will not be repeated here.

[0278] According to the trigonometric function relationship:

[0279] Among them, the function of the baffle D' is to block the evaporated material from being incident on the non-lens surface x2 of the lens unit 121. Therefore, the baffle is usually inclined toward the center O of the lens unit 121. Then, in order to enable the baffle D' to block the evaporation source W from emitting the evaporated material toward the non-lens surface x2 of the lens unit 121, it is necessary to make the minimum inclination angle of the line connecting the innermost point of any evaporation source in any radial cross-section of the Fresnel lens layer and the edge of its corresponding baffle close to the Fresnel lens layer relative to the normal of the plane where the projection screen is located be greater than the maximum inclination angle of the non-lens surface x2 of the lens unit 121 relative to the normal.

[0280] FIG52 illustrates a cross section along the symmetry axis II' of the projection screen. When setting the inclination angle of the baffle, it is necessary to ensure that the inclination angle of the baffle in any radial direction of the Fresnel lens layer satisfies the following conditions:

[0281] Among them, α max represents the maximum inclination angle of the non-lens surface of the lens unit relative to the normal of the plane where the projection screen is located in a cross section along any radial direction of the Fresnel lens layer, θ represents the minimum inclination angle of the line connecting the innermost point of the evaporation source and the edge of the baffle close to the Fresnel lens layer in the cross section relative to the normal, S1 represents the distance from the innermost point of the evaporation source to the normal of the edge passing through the baffle close to the Fresnel lens layer in the cross section, and h1 represents the distance from the plane including the innermost point of the evaporation source to the edge of the baffle close to the Fresnel lens layer.

[0282] The definitions of the normal line, the innermost point of the evaporation source in the cross section, and the plane including the innermost point of the evaporation source may refer to the above embodiments and will not be repeated here.

[0283] As described above, the inclination angle of the lens surface x1 of each lens unit 121 in the Fresnel lens layer 12 relative to the plane of the projection screen, as well as the inclination angle of the non-lens surface x2 of each lens unit 121 relative to the normal of the plane of the projection screen, may vary. Still taking the projection screen used in an ultra-short-throw projection system as an example, the inclination angle of the lens surface x1 of each lens unit 121 in the Fresnel lens layer 12 relative to the plane of the projection screen increases as the radius of the lens unit 121 increases. For the non-lens surface x2 of each lens unit 121, its inclination angle relative to the normal of the plane of the projection screen may vary with the lens surface x1 or remain unchanged.

[0284] In some embodiments, as shown in FIG49 , the non-lens surface x2 of each lens unit 121 has the same inclination angle relative to the normal t of the plane of the projection screen. For example, the non-lens surface x1 of each lens unit 121 is perpendicular to the plane of the projection screen, i.e., α = 0 in the above formula (2). In this case, the inclination angles of the baffles D' located between the evaporation source W and the Fresnel lens layer 12 can be the same, and the baffles D' can be parallel to each other.

[0285] In some embodiments, as shown in FIG52 , the inclination angle of the non-lens surface x2 of each lens unit 121 relative to the normal t of the plane on which the projection screen is located increases as the radius of the lens unit 121 increases. That is, the larger the radius of the lens unit 121, the larger the inclination angle of the non-lens surface x2 of the lens unit 121 relative to the normal. In this case, the inclination angle of the baffle D' needs to be set specifically for the lens unit 121 to which it corresponds. The width of the lens unit 121 is typically on the order of microns, while the width of the baffle D' is typically on the order of millimeters. Therefore, one baffle D' corresponds to multiple lens units 121. According to formula (2), the angle of the line connecting the edge of the baffle D' near the Fresnel lens layer and the innermost point of its corresponding evaporation source relative to the normal needs to be greater than the maximum angle of the non-lens surface x2 of each lens unit 121 corresponding to the baffle D' relative to the normal.

[0286] In a specific implementation, the distance between the evaporation source and the Fresnel lens layer can be 20 mm to 200 mm. The evaporation source is positioned closer to the side of the baffle away from the Fresnel lens layer. The width of the baffle can be 100 mm to 500 mm, and the spacing between adjacent baffles can be 50 mm to 200 mm. For example, the distance between the evaporation source and the Fresnel lens layer can be 100 mm, the width of the baffle can be 200 mm, and the spacing between adjacent baffles can be 100 mm.

[0287] Figure 53 is a schematic diagram of the cross-sectional structure along the BB' direction in Figure 40; Figure 54 is a schematic diagram of the positional relationship between the evaporation source, baffle, and Fresnel lens layer along the cross-sectional view shown in Figure 53. The BB' direction and the AA' direction in Figure 40 are parallel to each other, that is, they are both parallel to the vertical symmetry axis II' of the projection screen.

[0288] In some embodiments, as shown in Figures 53 and 54, an evaporation source W can be set on the side of the Fresnel lens layer 12 having multiple lens units 121, so that the evaporation source W and the multiple lens units 121 are at a set distance; and a plurality of spaced baffles D' are set between the evaporation source W and the multiple lens units 121, so that the baffles D' block the evaporation material emitted by the evaporation source W from forming on the non-lens surface x2 of the lens unit 121.

[0289] The difference from the embodiment shown in FIG54 is that the cross section shown in FIG54 is a cross section along the BB' direction in FIG40. When all cross sections of the Fresnel lens layer are cut along the BB' direction in FIG40, the inclination angle α' of the non-lens surface x2 of the lens unit 121 relative to the normal t of the plane where the projection screen is located will vary. If the maximum inclination angle α of the non-lens surface x2 of the lens unit 121 relative to the normal of the plane where the projection screen is located is found in a certain cross section,max ', then the positional relationship between the baffle D' and its corresponding evaporation source W can satisfy:

[0290] As shown in Figure 54, α max ' represents the maximum inclination angle of the non-lens surface x2 of the lens unit 121 obtained in all cross sections of the Fresnel lens layer 12 along the direction parallel to BB' relative to the normal of the plane where the projection screen is located, θ' represents the minimum inclination angle of the connecting line between the innermost point P of the evaporation source and the edge of the corresponding baffle D' close to the Fresnel lens layer in the cross section relative to the normal t, S1' represents the distance from the innermost point P of the evaporation source to the normal t of the edge passing through the baffle D' close to the Fresnel lens layer in the cross section, and h1' represents the distance from the plane including the innermost point P of the evaporation source to the edge of the baffle close to the Fresnel lens layer.

[0291] The normal line is the normal to the plane of the projection screen. The innermost point of the evaporation source refers to the point on the side of the evaporation source farthest from the corresponding baffle in the cross section. For example, in Figure 54, the left side of the evaporation source W is closer to baffle D', while the right side of the evaporation source is farther away from the baffle. Therefore, the innermost point of the evaporation source in Figure 54 refers to the rightmost point of the evaporation source. The plane including the innermost point P of the evaporation source refers to the plane passing through point P and parallel to the plane of the projection screen.

[0292] When the positional relationship between the baffle D' and the corresponding evaporation source W satisfies the above formula (3), the structure of the baffle D' and the evaporation source W can be simplified. Specifically, Figure 55 is a third schematic diagram of the planar structure of the evaporation source, baffle, and Fresnel lens layer provided in an embodiment of the present application; Figure 56 is a fourth schematic diagram of the planar structure of the evaporation source, baffle, and Fresnel lens layer provided in an embodiment of the present application.

[0293] At this time, as shown in FIG55 , the evaporation source W can be set to a strip extending along the first direction x, and the baffle D' can be set to a strip extending along the first direction x. The baffle D' is no longer a complex structure such as a conical surface, but is set to a plane.

[0294] The first direction x is parallel to the plane where the projection screen is located and perpendicular to the symmetry axis II' of the projection screen along the vertical direction.

[0295] This can simplify the structures of the vapor deposition source and the baffle while preventing the vapor deposition material from being formed on the non-lens surface of the lens unit.

[0296] Furthermore, as shown in Figure 56, if the Fresnel lens layer is moved along the first direction x during vapor deposition, it can be formed on the lens surface of the lens unit, thereby improving the productivity of the reflective layer. If combined with a roll-to-roll process, the productivity of projection screens can be further improved.

[0297] In a specific implementation, the distance between the evaporation source and the Fresnel lens layer can be 20 mm to 200 mm. The evaporation source is positioned closer to the side of the baffle away from the Fresnel lens layer. The width of the baffle can be 100 mm to 500 mm, and the spacing between adjacent baffles can be 50 mm to 500 mm. For example, the distance between the evaporation source and the Fresnel lens layer can be 100 mm, the width of the baffle can be 200 mm, and the spacing between adjacent baffles can be 100 mm.

[0298] Based on the same concept, when the functional layer in the projection screen no longer uses Fresnel lenses, but is composed of multiple lens structure layers extending along the above-mentioned first direction and arranged along the symmetry axis II' direction along the vertical direction of the projection screen, the structure of the evaporation source and baffle in the above-mentioned embodiment can also be applied.

[0299] Specifically, Figure 57 is a schematic diagram of the planar structure of the evaporation source, baffle, and lens structure layer provided in an embodiment of the present application. As shown in Figure 57, the projection screen has a lens structure layer 12', which includes a plurality of lens units 121'. These lens units 121' are all strip-shaped and extend along a first direction x. The lens units 121' are arranged along the direction of the symmetry axis II' of the projection screen. The first direction x is parallel to the plane of the projection screen, and the first direction x is perpendicular to the symmetry axis II' of the projection screen along the vertical direction. Similarly, the lens unit 121' includes a lens surface and a non-lens surface that are connected to each other. The lens surface is tilted relative to the plane of the projection screen, and the non-lens surface is used to connect the lens surface so that the tilt angle of the lens surface relative to the plane of the projection screen satisfies that the projection light incident on the reflective layer on the lens surface can be reflected in the direction of the audience.

[0300] For the lens structure layer 12' that meets the above-mentioned lens unit 121', the evaporation source W and the baffle D' can both be strip-shaped extending along the first direction x, and the baffle D' is flat. The structures of the lens structure layer 12', the evaporation source W and the baffle D' are all simplified.

[0301] When all cross sections of the lens structure layer 12' are taken along the direction parallel to the II' in Figure 57, the resulting cross-sectional structure is the same as the cross-sectional structure obtained along the II' direction in Figure 57. Therefore, the positional relationship between the baffle D' and its corresponding evaporation source W should be the same as that of the above formula (2), thereby preventing the evaporation material emitted by the evaporation source W from being formed on the non-lens surface of the lens unit 121'.

[0302] When this projection screen is used in an ultra-short-throw projection system, the tilt angle of the lens surface of each lens unit 121' in the lens structure layer 12' relative to the plane of the projection screen increases as the distance between the lens unit 121' and the bottom edge of the projection screen increases. As shown in FIG57 , the bottom edge of the projection screen is the lower side in FIG57 . If the non-lens surface of each lens unit 121' has the same tilt angle relative to the normal of the plane of the projection screen, for example, if the non-lens surface of each lens unit 121' is perpendicular to the plane of the projection screen, then the tilt angles of the baffles D' located between the evaporation source W and the functional layer 12' can be the same, and the baffles D' can be parallel to each other. If the tilt angle of the non-lens surface of each lens unit 121' relative to the normal of the plane of the projection screen increases as the distance between the lens unit 121' and the bottom edge of the projection screen increases, then the tilt angle of the baffle D' needs to be set specifically for the corresponding lens unit 121', and the baffles D' will no longer be parallel to each other.

[0303] In some embodiments, the reflective layer can be a single-layer structure or a multi-layer composite structure. When the reflective layer is a single-layer structure, a reflective metal material can be evaporated onto the lens surface of the lens unit using any of the above methods. When the reflective layer is a multi-layer composite structure, it can selectively reflect light in specific wavelength bands, thereby further improving the contrast of the projected image.

[0304] Finally, after the reflective layer is completed, the surface functional layer can be created. Located on the outermost side of the projection screen, the side closest to the audience, the surface functional layer protects the projection screen. Furthermore, the surface functional layer can be treated in various ways to achieve effects such as widening the viewing angle, resisting ambient light reflection, and resisting ceiling glare, depending on specific needs.

Claims

1. A projection screen, comprising: Surface functional layer; A Fresnel lens layer is located on one side of the surface functional layer; the Fresnel lens layer includes a plurality of lens units, the plurality of lens units are arranged in concentric circles that expand in sequence along the radial direction; the lens unit includes a lens surface that is tilted relative to the plane where the surface functional layer is located; and A reflective layer, at least covering the inclined surface of the lens unit; The inclination angle of the lens surface of each lens unit is sufficient to reflect the light emitted by the projection device to the reflective layer on the lens surface toward the viewer; The lens units are axially symmetrically distributed, the symmetry axis of each lens unit is perpendicular to the horizontal direction, and the center of the lens unit is located on the straight line where the symmetry axis is located; the inclination angle of the lens surface of at least one lens unit in the multiple groups of lens units at the first position is greater than the inclination angle at the second position, and the distance from the first position to the symmetry axis is greater than the distance from the second position to the symmetry axis.

2. The projection screen of claim 1, wherein: The center of each lens unit included in the projection screen is not located in the projection screen, and the inclination angles of the lens surfaces of all the lens units included in the projection screen increase with the increase of the vertical distance from the lens surface to the symmetry axis.

3. The projection screen of claim 2, wherein: The change of the inclination angle of the lens surface of the same lens unit satisfies a sine function.

4. The projection screen of claim 3, wherein: The inclination angle of the lens surface of each lens unit increases along the radial direction as the radius of the lens unit increases.

5. The projection screen of claim 4, wherein: The amplitude of the sine function satisfied by the inclination angle of the lens surface of each of the lens units increases as the radius of the lens unit increases.

6. The projection screen of claim 5, wherein: The variation of the inclination angle of the lens surface of the same lens unit is greater than 0 and less than or equal to 2.25°.

7. The projection screen of claim 6, wherein: The amount of change in the tilt angle of the lens surface of the lens unit increases as the size of the projection screen increases.

8. The projection screen of claim 1, wherein: The lens surfaces of the same lens unit have the same inclination angles at positions symmetrical to each other about the symmetry axis.

9. The projection screen of claim 1, wherein: The reflection layer is a wavelength selective reflection layer, and the reflectivity of the wavelength selective reflection layer to the projection light emitted by the projection device is greater than the reflectivity of light in other wavelength bands; The wavelength selective reflection layer has an equal thickness along a direction perpendicular to the lens surface.

10. The projection screen of claim 9, wherein: The inclination angle of the lens surface of each lens unit increases along the radial direction as the radius of the lens unit increases; The thickness of the wavelength selective reflection layer along a plane perpendicular to the projection screen increases as the radius of the lens unit increases.

11. The projection screen of claim 1, wherein: Any light-transmitting film layer in the projection screen contains low-valent oxides; the low-valent oxides are used to reduce the transmittance in the visible light band.

12. The projection screen of claim 11, wherein: The subvalent oxide is a metal subvalent oxide; The absorption capacity of the low-valent oxide to the visible light band decreases with the increase of oxygen content.

13. The projection screen of claim 11, wherein: The reflection layer is a wavelength selective reflection layer, and the reflectivity of the wavelength selective reflection layer to the projection light emitted by the projection device is greater than the reflectivity of light in other wavelength bands; The wavelength selective reflection layer comprises: Reflective layer; and At least one film layer group is located on a side of the reflective layer facing the surface functional layer; the film layer groups are stacked; Wherein, the film layer group comprises: a semi-transmissive layer, located on a side close to the surface functional layer; and The light-transmitting medium layer is located between the semi-transmitting layer and the reflective layer; the product of the refractive index and the thickness of the light-transmitting medium layer satisfies the condition for causing the outgoing light of the projection device to resonate.

14. The projection screen of claim 13, wherein: The light-transmitting medium layer includes the low-valent oxide.

15. The projection screen of claim 13, wherein: The light-transmitting medium layer comprises the low-valent oxide and the complete oxide.

16. The projection screen of claim 15, wherein: The light-transmitting dielectric layer comprises a first dielectric layer and a second dielectric layer which are stacked; wherein the first dielectric layer is made of low-valent oxide and the second dielectric layer is made of complete oxide; or, the first dielectric layer is made of complete oxide and the second dielectric layer is made of low-valent oxide.

17. The projection screen of claim 14 or 15, wherein: The low-valent oxide is Nb2O 5-x 、TiO 2-y or Ta2O 5-z One of; Among them, 0<x<5, 0<y<2, 0<z<5.

18. The projection screen of claim 13, wherein: The semi-transparent layer is a laminated structure formed by at least one metal selected from aluminum, niobium, silver and titanium; the thickness of the semi-transparent layer is 2nm to 20nm; The material of the reflective layer is aluminum, aluminum alloy, silver or silver alloy; the thickness of the reflective layer is greater than 50nm; The product of the thickness and the refractive index of the light-transmitting medium layer is 1200-1800.

19. A projection system comprising: A projection device, used for emitting projection light; and A projection screen, located at the light-emitting side of the projection device, wherein the projection screen is the projection screen according to any one of claims 1 to 18; Wherein, the projection device is an ultra-short-throw laser projection device; the projection device comprises: A three-color laser light source device, used for emitting three-primary-color lasers; a light modulation component, located at the light output side of the three-color laser light source device, and used to modulate the output laser light of the three-color laser light source device; and The projection lens is located at the light-emitting side of the light modulation component.

20. A method for making a projection screen, comprising: Fresnel lens layer manufacturing process: manufacturing a Fresnel lens layer; a surface of one side of the Fresnel lens layer has a plurality of lens units, each of the lens units is in the shape of concentric circles that are sequentially expanded and arranged along the radial direction; the lens unit includes a lens surface and a non-lens surface that are connected to each other; Wavelength selective reflection layer manufacturing process: forming a wavelength selective reflection layer on the surface of the lens unit; the thickness of the wavelength selective reflection layer along the plane perpendicular to the projection screen increases as the radius of each lens unit increases; and A surface functional layer manufacturing step: forming a surface functional layer on one surface of the Fresnel lens layer having the wavelength selective reflection layer.

21. The method of claim 20, wherein: The wavelength selective reflection layer comprises a semi-transmissive layer, a reflective layer and a transmissive medium layer; The semi-transparent layer, the reflective layer and the transparent medium layer are all manufactured by sputtering process; The light-transmitting medium layer is manufactured by a sputtering process, comprising: A correction plate is arranged above the sputtering source; A Fresnel lens layer is arranged above the correction plate, so that the lens unit of the Fresnel lens layer faces the sputtering source; Rolling the Fresnel lens layer during the sputtering process so that the Fresnel lens layer moves along a first direction above the sputtering source; Wherein, the correction plate includes a plurality of sub-correction plate pairs, the sub-correction plate pairs include two sub-correction plates, and a gap of a set distance is provided between the two sub-correction plates; each of the sub-correction plate pairs is arranged along a second direction; the first direction is perpendicular to the second direction, the second direction is perpendicular to a first side edge of the projection screen, and the first side edge is a side edge close to the center of the circle of the lens unit; the gap of each of the sub-correction plate pairs along the second direction increases as the radius of each lens unit increases.

22. A method for making a projection screen, comprising: A Fresnel lens layer is manufactured; one side surface of the Fresnel lens layer has a plurality of arc-shaped lens units, and the arc-shaped lens units are concentrically arranged; Each of the lens units comprises a lens surface and a non-lens surface connected to each other, the lens surface is inclined relative to the plane where the projection screen is located, and the non-lens surface is used to connect the lens surface; A vapor deposition source is arranged at a set position of the Fresnel lens layer to form a reflective layer on the lens surface of the plurality of lens units; the vapor deposition source is located on one side of the Fresnel lens layer having the plurality of lens units, and a set distance is provided between the vapor deposition source and the plurality of lens units; A surface functional layer is formed on a side of the Fresnel lens layer facing away from the reflective layer.

23. The method of claim 22, wherein: The step of arranging a vapor deposition source at a set position of the Fresnel lens layer comprises: The arc-shaped vapor deposition source is disposed at a set position of the Fresnel lens layer.

24. The method of claim 23, wherein: The center of the evaporation source arranged in an arc shape coincides with the center of the lens unit in the orthographic projection on the plane where the projection screen is located; the radius of the evaporation source arranged in an arc shape is greater than the radius of any lens unit in the Fresnel lens layer; The radius of the arc-shaped evaporation source relative to all lens units in the Fresnel lens layer satisfies: Among them, α i represents the inclination angle of the non-lens surface of the i-th lens unit relative to the normal line of the plane where the projection screen is located in a cross section along any radial direction of the Fresnel lens layer, θ i represents the inclination angle of the line connecting the innermost point of the vapor deposition source and the vertex of the i-th lens unit with respect to the normal line in the cross section, S i represents the distance from the innermost point of the evaporation source in the cross section to the normal line passing through the vertex of the i-th lens unit, and h represents the distance from the plane including the innermost point of the evaporation source to the vertex of the i-th lens unit; The innermost point of the evaporation source is the point in the cross section that is closest to the center of a circle, and the center of a circle is the center of the evaporation source arranged in an arc shape; the vertex of the lens unit is the intersection of the lens surface and the non-lens surface of the lens unit in the cross section that are close to the evaporation source; the plane including the innermost point of the evaporation source is parallel to the plane where the projection screen is located; i is any positive integer less than or equal to the number of lens units in the Fresnel lens layer.

25. The method of claim 22, wherein: The step of arranging a vapor deposition source at a set position of the Fresnel lens layer comprises: Disposing an arc-shaped evaporation source at a set position of the Fresnel lens layer; A plurality of baffles arranged at intervals are provided between the evaporation source and the plurality of lens units, and the baffles are used to block the evaporation material emitted from the evaporation source from being formed on the non-lens surface of the lens unit.

26. The method of claim 25, wherein: The baffle is in the shape of a partial surface of a cone; the orthographic projection of the vertex of the cone where the baffle is located on the plane where the projection screen is located coincides with the center of the lens unit.

27. The method of claim 26, wherein: The baffle meets the following requirements: Among them, α max represents the maximum inclination angle of the non-lens surface of the lens unit relative to the normal of the plane where the projection screen is located in a cross section along any radial direction of the Fresnel lens layer, θ represents the minimum inclination angle of the connecting line between the innermost point of the evaporation source and the edge of the baffle plate close to the Fresnel lens layer in the cross section relative to the normal, S1 represents the minimum distance from the innermost point of the evaporation source in the cross section to the normal passing through the edge of the baffle plate close to the Fresnel lens layer, and h1 represents the distance from the plane including the innermost point of the evaporation source to the edge of the baffle plate close to the Fresnel lens layer; The innermost point of the evaporation source is the point in the cross section that is closest to the center of a circle, and the center of a circle is the center of the evaporation source arranged in an arc shape; the plane including the innermost point of the evaporation source is parallel to the plane where the projection screen is located.

28. The method of claim 22, wherein: The step of arranging a vapor deposition source at a set position of the Fresnel lens layer comprises: Disposing a strip-shaped evaporation source at a set position of the Fresnel lens layer; A plurality of baffles arranged at intervals are provided between the evaporation source and the plurality of lens units, and the baffles are used to block the evaporation material emitted from the evaporation source from being formed on the non-lens surface of the lens unit.

29. The method of claim 28, wherein: The strip-shaped evaporation source extends along a first direction, the first direction is parallel to the plane where the projection screen is located, and the first direction is perpendicular to the symmetry axis of the projection screen along the vertical direction; The baffle is in the shape of a strip extending along the first direction, the baffle is a plane, and the baffle is arranged obliquely relative to the plane where the projection screen is located.

30. The method of claim 29, wherein: The baffle meets the following requirements: Among them, α max ' represents the maximum inclination angle of the non-lens surface of the lens unit relative to the normal of the plane where the projection screen is located in any cross section of the projection screen along the perpendicular direction, θ' represents the minimum inclination angle of the connecting line between the innermost point of the evaporation source and the edge of the baffle plate close to the Fresnel lens layer in the cross section relative to the normal, S1' represents the minimum distance from the innermost point of the evaporation source in the cross section to the normal of the edge passing through the baffle plate close to the Fresnel lens layer, and h1' represents the distance from the plane including the innermost point of the evaporation source to the edge of the baffle plate close to the Fresnel lens layer; The innermost point of the evaporation source is the point in the cross section that is farthest from the corresponding side of the baffle; the plane including the innermost point of the evaporation source is parallel to the plane where the projection screen is located.

Images