projection screen

Abstract

The present invention provides a projection screen. The projection screen includes a colored layer, a diffusion layer, a Fresnel lens layer, and a reflection layer. The Fresnel lens layer is a spherical Fresnel lens layer or an aspherical Fresnel lens layer. The Fresnel lens includes a plurality of annular protrusions protruding from its upper surface, the plurality of annular protrusions are arranged in an annular shape on the upper surface of the Fresnel lens, and the cross-sectional shape of each annular protrusion cut by a vertical plane of the upper surface of the Fresnel lens is a triangle, a multi-step staircase, or other shape. In the cross-section of each Fresnel lens, the width of a first side parallel to the upper surface of the Fresnel lens gradually changes, and the cross-sectional shape and width of each Fresnel lens also gradually change. This determines the light-collecting characteristics of the spherical Fresnel lens layer or the aspherical Fresnel lens layer. A scattering type microstructure is formed on the surface of each annular protrusion of the Fresnel lens layer, and the reflection layer is a metal reflection layer or an alloy reflection layer, and the reflection layer is manufactured by electroplating, vapor deposition, pouring, or coating process. Compared with conventional projection screens, the projection screen of the present invention has the features of high brightness and wide viewing angle.

Description

[Technical field]

[0001] The present invention is in the field of display technology, and in particular, relates to projection screens. [Background technology]

[0002] With the development of various display technologies, the projection display technology that can obtain a super-large display screen has attracted the attention of many people. In order to improve the quality of the screen displayed by the projection display technology to the quality of the screen displayed by the commonly used liquid crystal display technology or organic display technology, it is necessary not only to improve the quality of the projection device, but also to prepare a high-quality optical projection screen.

[0003] An optical projection screen is a projection screen that is composed of a series of fine optical structures and allows the light from the projector and the ambient light to be redistributed to the screen structure. The optical projection screen reduces the light intensity of the ambient light and increases the light intensity of the light from the projector, thereby improving the contrast, brightness, color reversibility, resolution, etc. of the screen, and meeting the requirement for high image quality. Fresnel screens are currently commonly used optical projection screens. Using the principle of Fresnel lens structure, Fresnel screens convert the light incident at a certain angle into parallel light, and then direct it into the user's eye to form an image. Reducing the influence of ambient light and improving the brightness and contrast of the screen are the challenges that engineers in the field of Fresnel screens are seeking.

[0004] In the prior art, diamond cutting is commonly used as a manufacturing method for manufacturing Fresnel lenses in Fresnel screens. The microstructure of the Fresnel lens manufactured by diamond cutting has the disadvantages of low precision and a large size between the recesses (usually 20 to 50 um). A microstructure with such low precision cannot improve the utilization rate of light. Although the precision of the microstructure can be improved, this may increase the difficulty of manufacturing the Fresnel lens. Therefore, reducing the difficulty of manufacturing the Fresnel lens under the premise of ensuring the utilization rate of light has become a challenge required by engineers in this technical field.

[0005] Currently, optical projection screens on the market, such as those shipped by Dai Nippon Printing Co., Ltd. (DNP) and Chengdu Feist Technology Co., Ltd., are all rigid screens that include a heavy back frame that supports the optical projection screen, and components such as a frame are attached to the back frame. However, such rigid screens are not only heavy, but also have the disadvantages of being large in volume and unable to be rolled up, making them inconvenient to transport and taking up a lot of space. Summary of the Invention [Problem to be solved by the invention]

[0006] In order to solve the problems of the prior art, the present invention provides the following Fresnel lens: [Means for solving the problem]

[0007] The Fresnel lens of the present invention includes a plurality of annular protrusions protruding from its upper surface, the plurality of annular protrusions are arranged in an annular shape on the upper surface of the Fresnel lens, the cross section of each annular protrusion cut by a vertical plane of the upper surface of the Fresnel lens is triangular, in the triangular cross section of the Fresnel lens, the side parallel to the upper surface of the Fresnel lens is the first side, and the other two sides are the second side and the third side. In the triangular cross section of each Fresnel lens, the height of each first side is the same, and the included angle between the third side and the first side is 90°.

[0008] The present invention provides another Fresnel lens. The Fresnel lens includes a plurality of annular protrusions protruding from its upper surface, the plurality of annular protrusions are arranged in an annular shape on the upper surface of the Fresnel lens, and the cross-sectional shape of each annular protrusion cut by a vertical plane of the upper surface of the Fresnel lens is a multi-step staircase type, the side parallel to the upper surface of the Fresnel lens is the first side, the side on which the steps are formed is the second side, and the side on which the steps are not formed is the third side, and the third side is perpendicular to the first side. Of the two sides of each step, one side is perpendicular to the first side, and the other side is parallel to the first side. Of the side of each step, the side is the side that is farthest from the first side and parallel to the first side. The vertical distance between the side and the first side is called the height H, and the height of the first side of each step is formed to be the same.

[0009] In the embodiment of the present invention, the height H of the first side is: JPEG0007623662000001.jpg17170When counting from the center toward the outside, the length Lj of the first side a1 in the cross section of the j-th triangle or multi-step staircase is as follows: JPEG0007623662000002.jpg14170 In this formula, P is an integer greater than or equal to 1, λ is the center wavelength, and f is the focal length of the Fresnel lens.

[0010] In an embodiment of the present invention, the height H of the first side is 1 to 20 μm.

[0011] In the embodiment of the present invention, the included angle β1 between the second side and the first side of each triangle is 65 to 81°.

[0012] In an embodiment of the present invention, the length of the first side is 0.02 to 0.3 mm.

[0013] In an embodiment of the present invention, the surface of the annular protrusion is formed with a scattering type microstructure.

[0014] In an embodiment of the present invention, a method for designing a Fresnel lens is provided. The Fresnel lens includes a plurality of annular protrusions protruding from its upper surface, the plurality of annular protrusions are arranged in an annular shape on the upper surface of the Fresnel lens, and the cross-sectional shape of each annular protrusion cut by a vertical plane of the upper surface of the Fresnel lens is a triangle or a multi-step staircase shape. In the cross-section of the annular protrusion having a triangular or multi-step staircase shape, the side parallel to the upper surface of the Fresnel lens is the first side. Counting from the center toward the outside, the length Lj of the first side of the j-th annular protrusion having a triangular or multi-step staircase shape is as follows: JPEG0007623662000003.jpg14170 In this formula, P is an integer greater than or equal to 1, λ is the center wavelength, and f is the focal length of the Fresnel lens.

[0015] In an embodiment of the present invention, the length Lj of the first side of the j-th annular protrusion, whose cross section is triangular or multi-step shaped, can be calculated by the following steps. In step 1, the radius of the spherical lens is assumed to be R, and the refractive index of the lens material is assumed to be n, and the focal length f of the spherical lens is calculated. The calculated focal length f of the spherical lens is JPEG0007623662000004.jpg13170JPEG0007623662000005.jpg19170In step 3, the following triangular relationship is obtained by assuming that the radius of the j-th annular protrusion is aj. JPEG0007623662000006.jpg17170By expanding this, we obtain the following formula. JPEG0007623662000007.jpg19170JPEG0007623662000008.jpg20170JPEG0007623662000009.jpg17170In step 4, the length Lj of the first side of the triangle cross section is calculated. The length Lj of the first side is obtained as follows. JPEG0007623662000010.jpg12170

[0016] In an embodiment of the present invention, a method for manufacturing a mold for manufacturing a Fresnel lens is provided. The mold for manufacturing the Fresnel lens includes a plurality of annular microstructure units protruding from its upper surface, the plurality of annular microstructure units are arranged in an annular shape on the upper surface of the Fresnel lens, and the cross-sectional shape of each annular microstructure unit cut by a vertical plane of the upper surface of the Fresnel lens is a triangle or a multi-step staircase shape. In the cross-section of the annular microstructure having a cross-sectional shape of a triangle or a multi-step staircase shape, the side parallel to the upper surface of the Fresnel lens is the first side. Counting from the center toward the outside, the length Lj of the first side of the j-th annular protrusion having a cross-sectional shape of a triangle or a multi-step staircase shape is as follows: JPEG0007623662000011.jpg12170 In this formula, P is an integer greater than or equal to 1, λ is the center wavelength, and f is the focal length of the Fresnel lens.

[0017] Just as the height H of the first side of the cross section of Examples 1 and 2 in which the cross section has a triangular or multi-stepped shape is defined, the height H of the first side of the cross section of the present invention in which the cross section has a triangular or multi-stepped shape is as follows. JPEG0007623662000012.jpg17170In this formula, n is the refractive index of the Fresnel lens.

[0018] In an embodiment of the present invention, a method for manufacturing a mold for manufacturing a Fresnel lens is provided, the method for manufacturing a mold for manufacturing a Fresnel lens includes the following steps: In step 1, a three-dimensional model drawing is provided. In step 2, at least one curvature function f1(x) is set, and the height of the midpoint of the three-dimensional model is determined by the curvature function f1(x). In step 3, a plurality of height regions are obtained by dividing the 3D model image in the height direction. In step 4, a grayscale image is obtained by projecting the 3D model drawing onto a plane. The grayscale image includes a number of pixel dots, each pixel dot including a position and a grayscale value of the pixel dot. The 3D model drawing is projected onto a horizontal plane, and the projection includes a number of points, each point including its position and height value. The position of each point corresponds to the position of a pixel dot in the grayscale image, and each height region of the 3D model drawing corresponds to a range of grayscale values. The grayscale value corresponding to the height value is obtained according to a corresponding function f2(x) corresponding to the height range of the height region in which the height value of the 3D model drawing is located and the range of grayscale values, and the grayscale value of the pixel dot corresponding to the grayscale image is obtained. In step 5, a photoresist is coated on the target carrier, and a patterned structure is obtained by performing lithography according to the grayscale image. A function f3(x) corresponding to the lithography time and the grayscale value is adopted, and a patterned structure is formed on the target carrier by performing exposure and development. In step 6, the patterned structure is transferred to another carrier by adopting UV printing method or metal growing method to form a mold corresponding to the pattern of the Fresnel lens.

[0019] In an embodiment of the present invention, a method for manufacturing a mold for manufacturing a Fresnel lens is provided, the method for manufacturing a mold for manufacturing a Fresnel lens includes the following steps: In step 1, a three-dimensional model drawing is provided. In step 2, at least one curvature function f1(x) is set, and the height of the midpoint of the three-dimensional model is determined by the curvature function f1(x). In step 3, a plurality of height regions are obtained by dividing the 3D model image in the height direction. In step 4, a grayscale image is obtained by projecting the 3D model drawing onto a plane. The grayscale image includes a number of pixel dots, each pixel dot including a position and a grayscale value of the pixel dot. The 3D model drawing is projected onto a horizontal plane, and the projection includes a number of points, each point including its position and height value. The position of each point corresponds to the position of a pixel dot in the grayscale image, and each height region of the 3D model drawing corresponds to a range of grayscale values. The grayscale value corresponding to the height value is obtained according to a corresponding function f2(x) corresponding to the height range of the height region in which the height value of the 3D model drawing is located and the range of grayscale values, and the grayscale value of the pixel dot corresponding to the grayscale image is obtained. In step 5, a number of binary images are sampled based on the grayscale image. In step 6, a photoresist is coated on the target carrier, and overlay lithography is performed with the multiple binary images, and exposure and development are performed to obtain a patterned structure on the target carrier. In step 7, the patterned structure is transferred to another carrier by adopting UV printing method or metal growing method to form a mold corresponding to the pattern of the Fresnel lens.

[0020] In an embodiment of the present invention, the shape of the three-dimensional model image is a cone. The radius R of the circular base of the cone is: JPEG0007623662000013.jpg19170The included angle α between the length L of the generatrix of the cone and the circular base is: JPEG0007623662000014.jpg23170In this formula, the height H of the first side is as follows. JPEG0007623662000015.jpg21170 In this formula, P is an integer greater than or equal to 1, λ is the center wavelength, n is the refractive index of the Fresnel lens, f is the focal length of the Fresnel lens, and N is the number of the annular microstructures.

[0021] In the embodiment of the present invention, the three-dimensional model of the three-dimensional model drawing is a hemisphere, and the radius R of the base of the hemisphere is as follows: JPEG0007623662000016.jpg19170

[0022] The curvature function f1(x) is: JPEG0007623662000017.jpg17170

[0023] In an embodiment of the present invention, the curvature function f1(x) is: JPEG0007623662000018.jpg23170In that formula, JPEG0007623662000019.jpg19170The independent variable x refers to the distance from a point located on any one radius of the circular base of the cone to the end of one of the radii located opposite the center of the circular base.

[0024] In an embodiment of the present invention, the cone is divided into N cone segments by a plane parallel to the base of the cone. Counting from the top of the cone, the generatrix length ΔLj+1 of the j+1th cone segment is: JPEG0007623662000020.jpg21170

[0025] In an embodiment of the present invention, the cone is divided into N cone segments by a plane parallel to the hemispherical base, where the length of each cone segment is: JPEG0007623662000021.jpg19170

[0026] In an embodiment of the present invention, the function f2(x) corresponding to the grayscale values ​​in the range of grayscale values ​​and the height values ​​in the height range of the j+1th section is as follows: JPEG0007623662000022.jpg26170

[0027] In an embodiment of the present invention, the function f2(x) corresponding to the grayscale values ​​in the range of grayscale values ​​and the height values ​​in the height range of the j+1th section is as follows: JPEG0007623662000023.jpg29170 The range of grayscale values ​​is greater than or equal to 0 and less than Qmax, where Qmax is the maximum grayscale value in the range of grayscale values, and the argument x refers to a height value within the height range.

[0028] In the embodiment of the present invention, the function f3(x) corresponding to the lithography time and the grayscale value is as follows: In that formula, η is the speed of lithography and the independent variable x refers to the grayscale value.

[0029] In an embodiment of the present invention, JPEG0007623662000025.jpg16170In that formula, JPEG0007623662000026.jpg14170

[0030] In an embodiment of the present invention, JPEG0007623662000027.jpg38170 In this formula, M is the number of steps, and i is an integer greater than or equal to 0 and less than M.

[0031] In an embodiment of the present invention, M-1 binary images are sampled with M number of steps. The grayscale value assigns black to pixel dots in the kth range, and white to pixel dots in other ranges to obtain the kth binary image; or The grayscale value assigns white to pixel dots in the kth range, and black to pixel dots in other ranges to obtain the kth binary image. The kth range covers at least the k-1th range, M is an integer greater than or equal to 2, black represents a binary 1, and white represents a binary 0.

[0032] In an embodiment of the present invention, the target carrier on which overlay lithography has been performed is baked to obtain a patterned structure.

[0033] The present invention provides a projection screen, which includes a colored layer, a diffusion layer, a Fresnel lens layer and a reflective layer, which are stacked in a thickness direction, or the projection screen includes a diffusion layer, a colored layer, a Fresnel lens layer and a reflective layer, which are stacked in a thickness direction.

[0034] The present invention provides a projection screen, which includes a colored layer, a Fresnel lens layer and a reflective layer, which are stacked in a thickness direction, and the Fresnel lens layer is doped with diffusing particles.

[0035] The present invention provides a projection screen, which includes a diffusion layer, a Fresnel lens layer and a reflection layer, which are stacked in a thickness direction, and the Fresnel lens layer is doped with colored particles.

[0036] The present invention provides a projection screen, which includes a Fresnel lens layer and a reflective layer stacked in a thickness direction, and the Fresnel lens layer has a base layer or a thin film having a predetermined haze ratio, to which colored particles and diffusing particles are added, or the Fresnel lens layer has colored particles and diffusing particles added.

[0037] In the embodiment of the present invention, the Fresnel lens layer is formed on a substrate, the substrate is made of a resin having a high light transmittance of 75% or more, and the thickness of the substrate is 10 to 200 μm.

[0038] In the embodiment of the present invention, the Fresnel lens layer and the substrate are integrally formed or the Fresnel lens layer is attached onto the substrate by the OCA.

[0039] In an embodiment of the present invention, the Fresnel lens layer is formed on a thin film having a predetermined haze ratio, the haze ratio of the thin film being 50-90%, and the thickness of the thin film being 50-200 μm.

[0040] In an embodiment of the present invention, a Fresnel lens layer is applied by OCA onto a thin film having a predetermined haze ratio.

[0041] In the embodiment of the present invention, the Fresnel lens layer is a spherical Fresnel lens layer or an aspheric Fresnel lens layer.

[0042] In an embodiment of the present invention, the thickness of the OCA is 10-200 μm.

[0043] In the embodiment of the present invention, the thickness of the colored layer is 10 to 200 μm, and the light transmittance of the colored layer is 50 to 90%.

[0044] In the embodiment of the present invention, the colored layer is a nickel plating layer, and the light transmittance of the colored layer is 50 to 90%.

[0045] In an embodiment of the present invention, the diffusion layer is a light-transmitting resin mixed with diffusing particles.

[0046] In an embodiment of the present invention, the thickness of the diffusion layer is 50 to 1000 μm.

[0047] In an embodiment of the present invention, the diffusion layer is a micro-nano structure having a diffusion function, and the shape of the lateral cross section of the diffusion layer is any one of a circular arc, a triangle, a polygon, a rectangle, a trapezoid or an irregular shape, or a combination of any two of these shapes.

[0048] In an embodiment of the present invention, the height of the micro-nano structure is 1-20 μm.

[0049] In an embodiment of the present invention, the micro-nanostructures are fabricated in a flexible material.

[0050] In the embodiment of the present invention, the diffusion layer is a semi-transparent semi-reflective film, and the haze ratio of the diffusion layer is 50-90%, and the light transmittance is 55-65%.

[0051] In an embodiment of the present invention, the reflective layer is a metal reflective layer or an alloy reflective layer.

[0052] In an embodiment of the present invention, the metal reflective layer includes aluminum, silver, gold, chromium, nickel and copper, and the alloy reflective layer includes nickel-chromium alloy, aluminum alloy and titanium alloy.

[0053] In the embodiment of the present invention, the reflective layer is an aluminum reflective layer, which is manufactured by plating or deposition method.

[0054] In the embodiment of the present invention, when the reflective layer is manufactured by a plating method, the thickness of the aluminum reflective layer is 0.04 to 3 μm.

[0055] In an embodiment of the present invention, the aluminum particles have a particle size of less than 500 nm.

[0056] In the embodiment of the present invention, when the reflective layer is manufactured by the deposition method, the thickness of the aluminum reflective layer is 10-20 μm.

[0057] In an embodiment of the present invention, the aluminum particles have a particle size greater than 5 μm.

[0058] In an embodiment of the present invention, the difference between the refractive index of the constituent material of the Fresnel lens layer and the refractive index of the diffusing particles is less than 0.4.

[0059] In an embodiment of the present invention, the colored particles have a particle size of less than 200 μm.

[0060] In an embodiment of the present invention, the particle size of the diffusing particles is 1-50 μm.

[0061] The present invention further provides a method for manufacturing a projection screen, which comprises: attaching any two of a diffusion layer, a colored layer and a Fresnel lens layer by OCA; or After producing the diffusion layer and the coloring layer by coating method, they are attached to the Fresnel lens layer by OCA, or After plating a color layer on one surface of the diffusion layer, the other surface of the diffusion layer is attached to the Fresnel lens layer by OCA; or The method includes plating a color layer onto one surface of the diffuser layer and then attaching the one surface of the color layer remote from the diffuser layer to a Fresnel lens layer by OCA.

[0062] In the embodiment of the present invention, after the Fresnel lens layer is attached, a reflective layer is formed on the surface of the Fresnel lens layer.

[0063] In an embodiment of the present invention, before the Fresnel lens layer is attached, a reflective layer is formed on the surface of the Fresnel lens layer.

[0064] In an embodiment of the present invention, the thickness of the OCA is 10-200 μm.

[0065] In an embodiment of the present invention, the Fresnel lens layer is manufactured by a roll-to-roll process.

[0066] In the embodiment of the present invention, an adhesive layer is applied onto a substrate, a thin film having a certain haze ratio, a diffusion layer or a colored layer, and then the adhesive layer is subjected to a roll-to-roll embossing process by the mold for producing the Fresnel lens to form a Fresnel lens layer.

[0067] In the embodiment of the present invention, the Fresnel lens layer is finally solidified by heating.

[0068] In an embodiment of the present invention, when the mold for producing the Fresnel lens is manufactured, a random dot structure is first formed on the surface of the mold for producing the Fresnel lens by a laser printing process, and then a certain material is pressed into the mold for producing the Fresnel lens to form a Fresnel lens layer, and a scattering type microstructure is formed on the surface of the annular protrusion of the Fresnel lens layer. Effect of the Invention

[0069] The technical features of the present invention can achieve the following effects of the invention. (1) The present invention provides a method for designing a mold for manufacturing a Fresnel lens, which can reduce the difficulty of manufacturing a Fresnel lens while ensuring the utilization rate of light rays. (2) The present invention provides a method for manufacturing a mold for manufacturing a Fresnel lens, which is simple to manufacture. (3) Compared with conventional projection screens, the projection screen of the present invention has the features of high brightness and a wide viewing angle. [Brief description of the drawings]

[0070] [Figure 1a] FIG. 1 is a plan view showing a structure of a Fresnel lens according to a first embodiment of the present invention. [Figure 1b] FIG. 1 is a cross-sectional view showing a structure of a Fresnel lens according to a first embodiment of the present invention. [Figure 1c] FIG. 2 is a cross-sectional view showing the structure of one microstructure unit of the Fresnel lens according to the first embodiment of the present invention. [Figure 2a]FIG. 11 is a plan view showing the structure of a Fresnel lens according to a second embodiment of the present invention. [Figure 2b] FIG. 1 is a cross-sectional view showing a structure of a Fresnel lens according to a second embodiment of the present invention. [Figure 2c] FIG. 11 is a cross-sectional view showing the structure of one microstructure unit of a Fresnel lens according to a second embodiment of the present invention. [Diagram 3] FIG. 11 is a geometric diagram used in designing a Fresnel lens according to a third embodiment of the present invention. [Figure 4a] FIG. 13 is a perspective view showing a conical three-dimensional model used in a manufacturing die for a Fresnel lens according to a fourth embodiment of the present invention. [Figure 4b] FIG. 11 is an axial cross-sectional view showing a conical three-dimensional model used in a manufacturing die for a Fresnel lens according to a fourth embodiment of the present invention. [Figure 5a] FIG. 13 is a diagram showing the structure of a projection screen according to a sixth embodiment of the present invention. [Figure 5b] FIG. 13 is a diagram showing the structure of a projection screen according to a sixth embodiment of the present invention. [Figure 5c] FIG. 13 is a diagram showing the structure of a projection screen according to a sixth embodiment of the present invention. [Figure 6] FIG. 13 is a diagram showing the structure of a projection screen according to a seventh embodiment of the present invention. [Figure 7] FIG. 13 is a diagram showing the structure of a projection screen according to an eighth embodiment of the present invention. [Figure 8] FIG. 13 is a diagram showing the structure of a projection screen according to a ninth embodiment of the present invention. [Figure 9] FIG. 13 is a diagram showing the structure of a projection screen according to a tenth embodiment of the present invention. [Figure 10] FIG. 1 shows the experimental results of a reflective layer formed on the surface of a Fresnel lens with random dots and produced by a plating process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0071] The following examples of the present invention will be used to explain the details of the present invention. Those skilled in the art can easily understand and implement the technical aspects of the present invention to solve certain technical problems and achieve certain inventive effects by referring to the following examples.

[0072] Unless otherwise specified, the raw materials and equipment of the present invention are those commonly used in the art and can be purchased from the market.Unless otherwise specified, the method of the present invention is a method commonly used in the art.

[0073] Example 1 FIG. 1 is a diagram showing the structure of a Fresnel lens according to an embodiment of the present invention. Specifically, FIG. 1a is a plan view showing the structure of a Fresnel lens according to an embodiment of the present invention, and FIG. 1b is a cross-sectional view showing the structure of a Fresnel lens according to an embodiment of the present invention. As shown in FIG. 1a to FIG. 1b, the Fresnel lens includes a plurality of annular protrusions protruding from its upper surface, the plurality of annular protrusions are arranged in an annular shape on the upper surface of the Fresnel lens, and the cross section of each annular protrusion cut by a vertical plane of the upper surface of the Fresnel lens is triangular. As shown in FIG. 1c, in the triangular cross section of the Fresnel lens, the side parallel to the upper surface of the Fresnel lens is the first side a1, and the other two sides are the second side b1 and the third side c1. In the triangular cross section of each Fresnel lens, the height H of each first side a1 is formed to be the same. In order to improve the convenience of manufacturing a mold for manufacturing a Fresnel lens by micro-nanolithography technology, it is preferable to set the included angle α1 between the third side c1 and the first side a1 to 90°. In the triangular cross section of each Fresnel lens, the width of the first side a1 gradually changes, but the height does not change, so that the triangular cross section of each Fresnel lens gradually changes, and the shape and width of the cross section also gradually change, thereby determining the light-collecting characteristics of the spherical Fresnel lens layer or the aspherical Fresnel lens layer.

[0074] The height H of the first side a1 of the triangular cross section of the Fresnel lens is as follows: In this formula, P is an integer greater than or equal to 1, λ is the center wavelength, and n is the refractive index of the Fresnel lens.

[0075] Counting from the center outward, the length Lj of the first side a1 in the j-th triangular cross section is: JPEG0007623662000029.jpg14170In this formula, P is an integer greater than or equal to 1, λ is the center wavelength, and f is the focal length of the Fresnel lens.

[0076] In an embodiment of the present invention, it is preferred that the included angle β1 between the second side b1 and the first side a1 of each triangle is 65 to 81°, the height of the first side a1 is 1 to 20 μm, and the length of the first side a1 is 0.02 to 0.3 mm.

[0077] Example 2 FIG. 2 is a diagram showing the structure of a Fresnel lens according to an embodiment of the present invention. Specifically, FIG. 2a is a plan view showing the structure of a Fresnel lens according to an embodiment of the present invention, and FIG. 2b is a cross-sectional view showing the structure of a Fresnel lens according to an embodiment of the present invention. As shown in FIG. 2a to FIG. 2b, the Fresnel lens includes a plurality of annular protrusions protruding from its upper surface, the plurality of annular protrusions are arranged in an annular shape on the upper surface of the Fresnel lens, and the cross-sectional shape of each annular protrusion cut by a vertical plane of the upper surface of the Fresnel lens is a multi-step staircase. As shown in FIG. 2c, in the multi-step staircase, the side parallel to the upper surface of the Fresnel lens is the first side a2, the side on which the staircase is formed is the second side b2, and the side on which the staircase is not formed is the third side c2. As shown in FIG. 2c, in order to manufacture a mold for manufacturing a Fresnel lens by micro-nano lithography technology, it is preferable that the third side c2 is perpendicular to the first side a2, and in the two sides of each staircase, one side d1 is perpendicular to the first side a2, and the other side d2 is parallel to the first side a2. In the side of each step, the side d2 is the side farthest from the first side a2 and parallel to the first side a2. The vertical distance between the side d2 and the first side a2 is called the height H, and the height H of each first side a2 is formed to be the same. In the cross section of the Fresnel lens, the width of the first side a2 gradually changes and the height does not change, so that the cross section of each Fresnel lens gradually changes, and the shape and width of the cross section also gradually change. This determines the light-collecting characteristics of the spherical Fresnel lens layer or the aspherical Fresnel lens layer.

[0078] The height H of the first side a2 is as follows: JPEG0007623662000030.jpg17170In this formula, P is an integer greater than or equal to 1, λ is the center wavelength, and n is the refractive index of the Fresnel lens.

[0079] When counting from the center toward the outside, the length Lj of the first side a2 in the cross section of the jth staircase is as follows: JPEG0007623662000031.jpg14170 In this formula, P is an integer greater than or equal to 1, λ is the center wavelength, and f is the focal length of the Fresnel lens.

[0080] In the embodiment of the present invention, it is preferable that the height of the first side a2 is 1 to 20 μm and the length of the first side a2 is 0.02 to 0.3 mm.

[0081] In the embodiment of the present invention, the cross-sectional shape of the annular protrusion is not limited to the above two shapes, and can be formed into other shapes. Specifically, the Fresnel lens includes a plurality of annular protrusions protruding from its upper surface, and the plurality of annular protrusions are arranged in an annular shape on the upper surface of the Fresnel lens, and the cross-sectional shape of each annular protrusion can be formed into various shapes. In the cross-section of the annular protrusion, the side parallel to the upper surface of the annular protrusion is called the first side, the side whose shape changes is called the second side, and the other side whose shape changes is called the third side. The vertical distance between the intersection of the second side and the third side and the first side is called the height H of the first side, and the height H of each first side is formed to be the same. In order to improve the convenience of manufacturing a mold for manufacturing a Fresnel lens by micro-nano lithography technology, it is preferable that the included angle α1 between the third side and the first side is 90°. In the cross-section of each Fresnel lens, the width of the first side gradually changes and the height does not change, so that the cross-section of each Fresnel lens gradually changes, and the shape and width of the cross-section also gradually change. This determines the light-collecting characteristics of the spherical or aspherical Fresnel lens layer.

[0082] Example 3 In an embodiment of the present invention, a method for designing a Fresnel lens is provided. The Fresnel lens includes a plurality of annular protrusions protruding from its upper surface, the plurality of annular protrusions are arranged in an annular shape on the upper surface of the Fresnel lens, and the cross-sectional shape of each annular protrusion cut by a vertical plane of the upper surface of the Fresnel lens is a triangle, a multi-step staircase, or other shape. In the cross-section of the annular protrusion having a cross-sectional shape of a triangle, a multi-step staircase, or other shape, the side parallel to the upper surface of the Fresnel lens is the first side. Counting from the center toward the outside, the length Lj of the first side of the j-th annular protrusion having a cross-sectional shape of a triangle, a multi-step staircase, or other shape is as follows: JPEG0007623662000032.jpg16170In this formula, P is an integer greater than or equal to 1, λ is the center wavelength, and f is the focal length of the Fresnel lens.

[0083] As shown in FIG. 3, the length Lj of the first side of the j-th annular protrusion, whose cross-sectional shape is a triangle, a multi-step shape, or other shape, can be calculated by the following steps:

[0084] In step 1, the radius of the spherical lens is assumed to be R, and the refractive index of the lens material is assumed to be n, and the focal length f of the spherical lens is calculated. The calculated focal length f of the spherical lens is JPEG0007623662000033.jpg13170

[0085] JPEG0007623662000034.jpg12170, and depression is performed j times on the j-th annular protrusion.

[0086] In step 3, by assuming that the radius of the j-th annular protrusion is aj, the following triangular relationship is obtained: JPEG0007623662000035.jpg20170

[0087] By expanding it, we obtain the following formula: JPEG0007623662000036.jpg19170

[0088] JPEG0007623662000037.jpg13170The approximate diameter is: JPEG0007623662000038.jpg18170

[0089] In step 4, calculate the length Lj of the first side of the j-th annular protrusion whose cross-sectional shape is a triangle, a multi-step staircase, or other shape. The length Lj of the first side is obtained as follows: JPEG0007623662000039.jpg15170

[0090] JPEG0007623662000040.jpg18170

[0091] Example 4 In an embodiment of the present invention, a method for manufacturing a mold for manufacturing a Fresnel lens is provided. The mold for manufacturing the Fresnel lens includes a plurality of annular microstructure units protruding from its upper surface, the plurality of annular microstructure units are arranged in an annular shape on the upper surface of the Fresnel lens, and the cross-sectional shape of each annular microstructure unit cut by a vertical plane of the upper surface of the Fresnel lens is a triangle, a multi-step staircase, or other shape. In the cross-section of the annular microstructure having a cross-sectional shape of a triangle, a multi-step staircase, or other shape, the side parallel to the upper surface of the Fresnel lens is the first side. Counting from the center toward the outside, the length Lj of the first side of the j-th annular protrusion having a cross-sectional shape of a triangle, a multi-step staircase, or other shape is as follows: JPEG0007623662000041.jpg11170 In this formula, P is an integer greater than or equal to 1, λ is the center wavelength, and f is the focal length of the Fresnel lens.

[0092] Just as defining the height H of the first side of the cross section of Examples 1 and 2, in which the cross section has a triangular, multi-step, or other shape, the height H of the first side of the cross section of the present invention, in which the cross section has a triangular, multi-step, or other shape, is as follows: JPEG0007623662000042.jpg17170In this formula, n is the refractive index of the Fresnel lens.

[0093] The manufacturing method of the mold for manufacturing the Fresnel lens includes the following steps.

[0094] In step 1, a three-dimensional model diagram is provided. Specifically, as shown in Fig. 4a, the shape of the three-dimensional model diagram is preferably a cone shape.

[0095] The radius R of the circular base of the cone is: JPEG0007623662000043.jpg18170

[0096] The included angle α between the length L of the generatrix of the cone and the circular base is: JPEG0007623662000044.jpg23170

[0097] In this formula, the height H of the first side is: JPEG0007623662000045.jpg20170In the formula, P is an integer greater than or equal to 1, λ is the center wavelength, n is the refractive index of the Fresnel lens, f is the focal length of the Fresnel lens, and N is the number of annular microstructures.

[0098] In an embodiment of the present invention, the three-dimensional model of the three-dimensional model drawing is preferably a hemisphere. The radius of the base of the hemisphere is R, and the radius R is as follows: JPEG0007623662000046.jpg18170 In the formula, P is an integer greater than or equal to 1, λ is the center wavelength, n is the refractive index of the Fresnel lens, f is the focal length of the Fresnel lens, and N is the number of annular microstructure units.

[0099] In step 2, at least one curvature function f1(x) is set, and the height of the midpoint of the three-dimensional model is determined by the curvature function f1(x). The curvature function f1(x) is as follows: JPEG0007623662000047.jpg16170In that formula, the independent variable x refers to the distance from a point located on any one radius of the circular base of the cone to the end of one of the radiuses located opposite the center of the circular base.

[0100] In an embodiment of the present invention, the preferred curvature function f1(x) is: JPEG0007623662000048.jpg21170

[0101] In that formula, JPEG0007623662000049.jpg18170The independent variable x refers to the distance from a point located on any one radius of the circular base of the cone to the end of one of the radii located opposite the center of the circular base.

[0102] In step 3, a number of height regions are obtained by dividing the 3D model in the height direction. Specifically, as shown in Fig. 4b, the cone is divided into N cone segments by a plane parallel to the base of the cone. Counting from the top of the cone, the generatrix length ΔLj+1 of the j+1th cone segment is: JPEG0007623662000050.jpg20170

[0103] In an embodiment of the present invention, the cone is divided into N cone segments by a plane parallel to the hemispherical base, where the length of each cone segment is: JPEG0007623662000051.jpg18170

[0104] In step 4, a grayscale image is obtained by projecting the 3D model image onto a plane. The grayscale image includes a number of pixel dots, each pixel dot including a position and a grayscale value. The 3D model image is projected onto a horizontal plane and includes a number of points, each point including its position and height value. The position of each point corresponds to the position of a pixel dot in the grayscale image, and each height section of the 3D model image corresponds to a range of grayscale values. For example, the range of grayscale values ​​is 0 to 64 or 0 to 256. A grayscale value corresponding to the height value is obtained according to a corresponding function f2(x) corresponding to the height range of the height section in which the height value of the 3D model image is located and the range of grayscale values, and a grayscale value of a pixel dot corresponding to the grayscale image is obtained. Specifically, the function f2(x) corresponding to the grayscale value within the range of grayscale values ​​and the height value within the height range of the j+1th section is as follows: JPEG0007623662000052.jpg24170

[0105] In an embodiment of the present invention, the function f2(x) corresponding to the grayscale values ​​in the range of grayscale values ​​and the height values ​​in the height range of the j+1th section is as follows: JPEG0007623662000053.jpg28170 The range of grayscale values ​​is greater than or equal to 0 and less than Qmax, where Qmax is the maximum grayscale value in the range of grayscale values, and the argument x refers to a height value within the height range.

[0106] In step 5, a photoresist is coated on the target carrier, and lithography is performed according to the grayscale image to obtain a patterned structure. The grayscale image is divided into a number of units, and then lithography is performed thereon. A function f3(x) corresponding to the lithography time and the grayscale value is adopted, and an inclined surface is formed on the target carrier by performing exposure and development. The higher the grayscale value of the pixel dots in the grayscale image, the longer the lithography time and the deeper the lithography depth. The smaller the grayscale value of the pixel dots in the grayscale image, the shorter the lithography time and the shallower the lithography depth. The function f3(x) corresponding to the lithography time and the grayscale value is as follows: In this formula, η is the lithography speed, i.e., the lithography depth corresponding to a unit time. The independent variable x refers to the grayscale value.

[0107] In an embodiment of the present invention, when selecting a range of grayscale values, the lithography time remains unchanged. JPEG0007623662000055.jpg17170In that formula, JPEG0007623662000056.jpg9170

[0108] In an embodiment of the present invention, JPEG0007623662000057.jpg36170 In this formula, M is the number of steps, and i is an integer greater than or equal to 0 and less than M.

[0109] In step 6, the patterned structure is transferred to another carrier by adopting UV printing method or metal growing method to form a mold corresponding to the pattern of the Fresnel lens.

[0110] Compared with the conventional technology, the method for manufacturing a mold for manufacturing a Fresnel lens of this embodiment obtains a grayscale image by projecting a three-dimensional model drawing onto a plane, and divides the three-dimensional model drawing into a plurality of height zones according to height. The height range of each height zone corresponds to a range of grayscale values. Thus, the three-dimensional model drawing can be easily converted into a grayscale image, and the mold for manufacturing a Fresnel lens can be easily manufactured.

[0111] Example 5 The present invention provides a method for manufacturing a mold for manufacturing a Fresnel lens, the method for manufacturing the mold for manufacturing a Fresnel lens includes the following steps:

[0112] In step 1, a three-dimensional model drawing is provided.

[0113] In step 2, at least one curvature function is set, and the height of the midpoint of the three-dimensional model is determined by the curvature function.

[0114] In step 3, a plurality of height regions are obtained by dividing the 3D model image in the height direction.

[0115] In step 4, a grayscale image is obtained by projecting the 3D model drawing onto a plane.

[0116] The specific processes of steps 1 to 4 are the same as steps 1 to 4 in the fourth embodiment, so they will not be described again here.

[0117] In step 5, a plurality of binary images are sampled based on the grayscale image. The number of steps, M, samples M-1 binary images. The grayscale value assigns black (white) to pixel dots in the first range, and the grayscale value assigns white (black) to pixel dots in the other range. The grayscale values ​​assign black (white) to pixel dots in the second range, and the grayscale values ​​assign white (black) to pixel dots in the other range. The grayscale value assigns black (white) to pixel dots in the kth range, and the grayscale value assigns white (black) to pixel dots in the other range. The kth range covers at least the k-1th range, and M is an integer greater than or equal to 2. Black represents a binary 1 and white represents a binary 0.

[0118] In step 6, a photoresist is coated on the target carrier, and overlay lithography is performed with the plurality of binary images, and then exposure and development are performed to obtain a multi-step patterned structure on the target carrier.

[0119] In a preferred embodiment of the present invention, the target carrier on which overlay lithography has been performed is baked to obtain a patterned structure.

[0120] In step 7, the patterned structure is transferred to another carrier by adopting UV printing method or metal growing method to form a mold corresponding to the pattern of the Fresnel lens.

[0121] In this embodiment, a mold for manufacturing a Fresnel lens is manufactured by performing overlay lithography using multiple binary images, thereby solving the drawbacks of time-consuming and low efficiency when manufacturing a mold for manufacturing a Fresnel lens using gray scale lithography.

[0122] Example 6 The present invention provides a projection screen. As shown in Figure 5a-5b, the projection screen includes a colored layer, a diffusion layer, a Fresnel lens layer, and a reflective layer, which are stacked in the thickness direction. The Fresnel lens layer is a spherical Fresnel lens layer or an aspherical Fresnel lens layer.

[0123] In an embodiment of the present invention, as shown in FIG. 5c, the projection screen includes a diffusion layer, a colored layer, a Fresnel lens layer and a reflective layer, which are stacked in the thickness direction in that order.

[0124] In an embodiment of the present invention, the projection screen includes a diffusion layer, a Fresnel lens layer, a colored layer and a reflective layer, which are stacked in the thickness direction, the colored layer is formed on the surface of the plurality of annular protrusions of the Fresnel lens layer, and the reflective layer is formed on the surface of the colored layer.

[0125] The colored layer has a function of absorbing the ambient light incident on the projection screen, reducing the black brightness of the image, and improving the contrast of the image. The colored layer is formed by uniformly mixing a colorant with a resin having a high light transmittance of 75% or more, and then injecting the mixture with an injection molding device or performing thermal curing. It is preferable to use a dye or pigment of a dark color such as gray or black as the colorant. For example, carbon black, graphite, black metal salts such as iron oxide, etc. can be used. As the resin having a high light transmittance, PET (polyethylene terephthalate) resin, PC (polycarbonate) resin, MS (methyl methacrylate-styrene) resin, MBS (methyl methacrylate-butadiene-styrene) resin, TAC (triethylene cellulose) resin, PEN (polyethylene glycol naphthalene dicarboxylate) resin, acrylic resin, etc. can be used. The thickness of the colored layer is 10 to 200 μm, and the light transmittance of the colored layer is preferably 50 to 90%.

[0126] In the embodiment of the present invention, the colored layer is a nickel plating layer, and the light transmittance of the colored layer is preferably 50 to 90%.

[0127] The diffusion layer is for expanding the viewing angle and increasing the uniformity of the light brightness in the screen. As shown in FIG. 5a, the diffusion layer can be a thin film obtained by uniformly mixing the diffusion particles having the function of diffusing light scattering with the resin having light transmittance. In order to expand the viewing angle and increase the uniformity of the brightness surface, the difference between the refractive index of the resin and the refractive index of the diffusion particles is set to 0.4 or less. As the resin material, it is preferable to use PET (polyethylene terephthalate) resin, PC (polycarbonate) resin, MS (methyl methacrylate-styrene) resin, MBS (methyl methacrylate-butadiene-styrene) resin, TAC (triethylene cellulose) resin, PEN (polyethylene glycol naphthalene dicarboxylate) resin, acrylic resin, etc. As the diffusion particles, inorganic diffusion particles and / or organic diffusion particles can be used. The inorganic diffusion particles may be particles composed of one or more of aluminum oxide, antimony oxide, cadmium oxide, tantalum oxide, zirconia, iron oxide, copper oxide, lead oxide, manganese oxide, tin oxide, tungsten oxide, zinc selenide, niobium oxide, zinc telluride, vanadium, molybdenum oxide, zinc sulfide, zinc oxide, cadmium sulfide, cadmium selenide, titanium oxide, and lead sulfide. The organic diffusion particles may be one or more of polystyrene, acrylic resin, polyurethane, polytetrafluoroethylene, melamine resin, benzyl melamine resin, epoxy resin, silicone resin, and the like. The particle size of the diffusion particles is 1 to 50 μm, preferably 5 to 30 μm. The thickness of the diffusion layer is 50 to 1000 μm, preferably 188 μm.

[0128] In the embodiment of the present invention, as shown in Fig. 5b, the diffusion layer is a micro-nano structure having a diffusion function, and its height is 1-20μm. The cross-sectional shape of the diffusion layer in the horizontal direction can be any one of a circular arc, a triangle, a polygon, a rectangle, a trapezoid, or an irregular shape, or a combination of any two shapes. In order to achieve the purpose of rolling up the projection screen, the projection screen is flexible, and the micro-nano structure is preferably made of a flexible material, such as resin.

[0129] In the embodiment of the present invention, the diffusion layer is a semi-transparent semi-reflective film, and the diffusion layer preferably has a haze ratio of 50-90% and a light transmittance of 55-65%.

[0130] The reflective layer can be a metal reflective layer or an alloy reflective layer. The metal reflective layer can include, but is not limited to, aluminum, silver, gold, chromium, nickel, and copper. The alloy reflective layer can include, but is not limited to, nickel-chromium alloy, aluminum alloy, and titanium alloy.

[0131] In a preferred embodiment of the present invention, the reflective layer is an aluminum reflective layer, and the reflective layer is preferably manufactured by a plating or deposition method. When the reflective layer is manufactured by a plating method, the thickness of the reflective layer is preferably 0.04-3 μm, and the diameter of the aluminum particles is preferably 500 nm or less. When the reflective layer is manufactured by a deposition method, the thickness of the reflective layer is preferably 10-20 μm, and the diameter of the aluminum particles is preferably more than 5 μm.

[0132] The Fresnel lens layer serves to adjust the propagation direction of the projected light ray. The Fresnel lens layer can be the Fresnel lens of Examples 1-2.

[0133] In an embodiment of the present invention, in order to ensure that the projection screen has higher brightness (i.e., gain) and a larger viewing angle (i.e., half viewing angle), a scattering microstructure is formed on the surface of the annular protrusion of the Fresnel lens layer, as shown in FIG. 5c.

[0134] In the embodiment of the present invention, the Fresnel lens layer is formed on a substrate, which is made of a resin having a high light transmittance of 75% or more, and the thickness of the substrate is preferably 10 to 200 μm.

[0135] In an embodiment of the present invention, the Fresnel lens layer and the substrate may be integrally formed.

[0136] In the embodiment of the present invention, the Fresnel lens layer is attached onto the substrate by an OCA, the thickness of which is preferably 10 to 200 μm.

[0137] In an embodiment of the present invention, the Fresnel lens layer is formed on a thin film having a predetermined haze ratio. The haze ratio of the thin film is preferably 50 to 90%, and the thickness of the thin film is preferably 50 to 200 μm.

[0138] In the embodiment of the present invention, the Fresnel lens layer is attached onto a thin film or substrate having a predetermined haze ratio by an OCA, and the thickness of the OCA is preferably 10 to 200 μm.

[0139] The present invention further provides a method for manufacturing a projection screen.

[0140] The diffusion layer, the colored layer, and the Fresnel lens layer can be attached in the order described by the OCA, or the colored layer, the diffusion layer, and the Fresnel lens layer can be attached in the order described by the OCA. The thickness of the OCA is 10 to 200 μm.

[0141] In the embodiment of the present invention, the diffusion layer, the colored layer and the Fresnel lens layer are prepared by a coating method, and then they are attached to the Fresnel lens layer by an OCA, or the colored layer, the diffusion layer and the Fresnel lens layer are prepared by a coating method, and then they are attached to the Fresnel lens layer by an OCA, and the thickness of the OCA is 10-200 μm.

[0142] In the embodiment of the present invention, a Fresnel lens layer is manufactured by a roll-to-roll process. Specifically, first, an adhesive layer is applied onto a substrate, a thin film having a predetermined haze ratio, a diffusion layer, or a colored layer. Next, a Fresnel lens layer is formed by carrying out a roll-to-roll embossing technique on the adhesive layer using the mold for manufacturing Fresnel lenses of Examples 4 to 5. Finally, the Fresnel lens layer is solidified by heating.

[0143] In the embodiments of the present invention, in order to ensure that the projection screen has higher brightness (i.e., increased brightness) and a larger viewing angle (i.e., half viewing angle), when manufacturing the mold for manufacturing the Fresnel lens in the embodiments 4 and 5, a random dot structure is first formed on the surface of the mold for manufacturing the Fresnel lens by a laser printing process. Then, a Fresnel lens layer is formed by pressing a certain material with the mold for manufacturing the Fresnel lens, and a scattering type microstructure is formed on the surface of the annular protrusion of the Fresnel lens layer.

[0144] In the embodiment of the present invention, the color layer can be plated on one surface of the diffusion layer, and then the other surface of the diffusion layer can be attached to the Fresnel lens layer by OCA, or the color layer can be plated on one surface of the diffusion layer, and then the surface of the color layer remote from the diffusion layer can be attached to the Fresnel lens layer by OCA, and the thickness of the OCA is 10-200μm.

[0145] After the Fresnel lens layer is attached, a reflective layer is formed on the surface of the Fresnel lens layer.

[0146] In a preferred embodiment of the present invention, a reflective layer is formed on the surface of the Fresnel lens layer before the Fresnel lens layer is attached.

[0147] In the embodiment of the present invention, a roll-to-roll process is used as the bonding method.

[0148] Example 7 The present invention provides a projection screen, which includes a colored layer, a Fresnel lens layer and a reflective layer, which are stacked in a thickness direction, as shown in Fig. 6. The Fresnel lens layer is a spherical Fresnel lens layer or an aspherical Fresnel lens layer.

[0149] The colored layer and the reflective layer can be referred to in the description of Example 6, and will not be described again here. The manufacturing method of the Fresnel lens layer can also be referred to in the description of Example 6, and will not be described again here. When manufacturing the Fresnel lens layer of this embodiment, the diffusing particles are added to the adhesive layer. The difference between the refractive index of the constituent material of the Fresnel lens layer and the refractive index of the diffusing particles is less than 0.4. The diffusing particles can be the inorganic or organic diffusing particles in Example 5, and will not be described again here.

[0150] Since the projection screen of the present embodiment does not have a diffusion layer, the projection screen of the present invention can be made thinner and softer, which makes it easier to roll up. In addition, the Fresnel lens layer is doped with diffusion particles, which further increases the viewing angle of the image projected on the projection screen and further improves the uniformity of the luminance surface.

[0151] The present invention further provides a method for manufacturing a projection screen.

[0152] The colored layer and the Fresnel lens layer are laminated in order by the OCA, the thickness of which is 10 to 200 μm.

[0153] After the Fresnel lens layer is attached, a reflective layer is formed on the surface of the Fresnel lens layer.

[0154] In an embodiment of the present invention, before the Fresnel lens layer is attached, a reflective layer is formed on the surface of the Fresnel lens layer.

[0155] In the embodiment of the present invention, a roll-to-roll process is used as the bonding method.

[0156] Example 8 The present invention provides a projection screen, which includes a diffusion layer, a Fresnel lens layer and a reflective layer, which are stacked in a thickness direction in this order, as shown in Fig. 7. The Fresnel lens layer is a spherical Fresnel lens layer or an aspherical Fresnel lens layer.

[0157] The diffusion layer and the reflective layer can be referred to in the description of Example 6, and will not be described again here. The manufacturing method of the Fresnel lens layer can also be referred to in the description of Example 6, and will not be described again here. When manufacturing the Fresnel lens layer of this embodiment, colored particles are added to the adhesive layer of the Fresnel lens layer. It is preferable to use a dye or pigment of a dark color such as gray or black as the material of the colored particles. For example, carbon black, graphite, metal salts such as black iron oxide, etc. can be used. The particle size of the colored particles is preferably less than 200 μm.

[0158] Since the projection screen of the present embodiment does not have a colored layer, the projection screen of the present invention can be made thinner and softer, which makes it easier to roll up. In addition, since the Fresnel lens layer contains colored particles, the black brightness of the image caused by the ambient light can be greatly reduced, and the contrast of the image can be greatly improved.

[0159] The present invention further provides a method for manufacturing a projection screen.

[0160] The diffusion layer and the Fresnel lens layer are laminated in order by the OCA, whose thickness is 10 to 200 μm.

[0161] After the Fresnel lens layer is attached, a reflective layer is formed on the surface of the Fresnel lens layer.

[0162] In an embodiment of the present invention, before the Fresnel lens layer is attached, a reflective layer is formed on the surface of the Fresnel lens layer.

[0163] In the embodiment of the present invention, a roll-to-roll process is used as the bonding method.

[0164] Example 9 The present invention provides a projection screen, which includes a Fresnel lens layer and a reflective layer stacked in a thickness direction, as shown in Fig. 8. The Fresnel lens layer is a spherical Fresnel lens layer or an aspherical Fresnel lens layer.

[0165] The reflective layer can be described in Example 6, so it will not be described again here. The manufacturing method of the Fresnel lens layer can also be described in Example 6, so it will not be described again here. When manufacturing the Fresnel lens layer of this embodiment, colored particles and diffusing particles are added to the substrate layer of the Fresnel lens layer or a thin film having a predetermined haze ratio. It is preferable to use a dye or pigment of a dark color such as gray or black as the material of the colored particles. For example, carbon black, graphite, black metal salt such as iron oxide, etc. can be used. Inorganic diffusing particles and / or organic diffusing particles can be used as the diffusing particle. The material of the diffusing particle can be described in Example 6, so it will not be described again here. The particle size of the colored particles is 200 μm or less. The particle size of the diffusing particles is 1 to 50 μm, preferably 5 to 30 μm. The thickness of the substrate layer is 50 to 200 μm.

[0166] Since the projection screen of the present embodiment does not have a colored layer and a diffusion layer, the projection screen of the present invention can be made thinner and softer. This makes it easier to roll up the projection screen of the present invention. Such a projection screen can greatly reduce the black brightness of the image caused by the ambient light and greatly improve the contrast of the image. In addition, the viewing angle of the image projected on the projection screen can be further increased and the uniformity of the luminance surface can be greatly improved.

[0167] Example 10 The present invention provides a projection screen, which includes a Fresnel lens layer and a reflective layer stacked in a thickness direction, as shown in Fig. 9. The Fresnel lens layer is a spherical Fresnel lens layer or an aspherical Fresnel lens layer.

[0168] The reflective layer can be described in Example 6, and will not be described again. The manufacturing method of the Fresnel lens layer can also be described in Example 6, and will not be described again. When manufacturing the Fresnel lens layer of this embodiment, colored particles and diffusing particles are added to the adhesive layer of the Fresnel lens layer. The colored particles and diffusing particles can be described in Example 9, and will not be described again.

[0169] The present invention uses the Fresnel lens manufacturing molds of Examples 4-5 to carry out embossing on the Fresnel lens layers of Examples 5-10. The Fresnel lens manufacturing molds of Examples 4-5 have random dot structures formed on their surfaces by a laser printing process, and the reflective layer is manufactured by a plating process (e.g., electroplating, vapor deposition, or sputtering). This makes it possible to obtain higher brightness (i.e., increased profit) and a larger viewing angle (i.e., half viewing angle) than the conventional projection screen. The Fresnel lens layer of the conventional projection screen is embossed on its Fresnel lens layer by using the Fresnel lens manufacturing molds of Examples 4-5, but the random dot structures are not formed on the surface of the conventional Fresnel lens manufacturing molds by a laser printing process, and the conventional reflective layer is manufactured by an aluminum spray process. The experimental data is shown in FIG. 10. The cause is unclear, and further research is being conducted.

[0170] The present invention is not limited to the technical matters of the above embodiments, but may include other technical matters, and the present invention does not describe them one by one. That is, the technical matters defined in the claims of the present invention may be implemented in various ways.

[0171] Matters not described in the present specification may be common knowledge understood by those skilled in the art.

[0172] The terms "including," "comprise," and the like used in the specification and claims of the present invention are open ended terms. That is, they mean "including, but not limited to." The term "approximately" means that the matter has a margin of error. A person skilled in the art can solve a given technical problem and achieve a given technical effect with the margin of error of the present invention.

[0173] It should be noted that the terms "comprise", "include", and the like in the present invention are open-ended terms. That is, a product or system including a set of elements may include not only the elements explicitly described, but also other elements not described or elements inherent in the product or system. Unless otherwise specified, an element defined by the term "comprises an item" may include not only the elements that include the item, but also other similar elements in the product or system that includes the element.

[0174] Although the preferred embodiment of the present invention has been described above, the embodiment is merely an example of the present invention, and the present invention is not limited to the configuration of the embodiment. By changing the conditions and environment of the implementation, appropriate improvements and modifications can be made to the above embodiment without departing from the spirit of the present invention. Those skilled in the art can change, improve, substitute, and modify the design without departing from the spirit of the present invention, and it is natural that such changes are included in the scope of the claims of the present invention.

Claims

1. A method for manufacturing a projection screen, the projection screen comprising: a colored layer, a diffusion layer, a Fresnel lens layer, and a reflective layer, which are sequentially superimposed in a thickness direction; a colored layer, a Fresnel lens layer, and a reflective layer, which are sequentially superimposed in a thickness direction; a diffusion layer, a Fresnel lens layer, and a reflective layer, which are sequentially superimposed in a thickness direction; or a Fresnel lens layer and a reflective layer, which are sequentially superimposed in a thickness direction; The Fresnel lens layer has a scattering type microstructure formed on a surface of the plurality of annular protrusions by pressing the material of the Fresnel lens layer through a random point structure on a surface of a mold for manufacturing the Fresnel lens layer. The manufacturing method of the projection screen includes: attaching any two of the diffusion layer, the colored layer, and the Fresnel lens layer by OCA; or After preparing the diffusion layer and the color layer by a coating method, they are attached to the Fresnel lens layer by OCA; or The color layer is plated on one surface of the diffusion layer, and then the other surface of the diffusion layer is attached to the Fresnel lens layer by OCA; or 11. A method for manufacturing a projection screen, comprising the steps of plating the colored layer on one surface of the diffusion layer, and then attaching the one surface of the colored layer away from the diffusion layer to the Fresnel lens layer by an OCA.

2. 2. The method of claim 1, wherein the reflective layer is a metal reflective layer or an alloy reflective layer, the metal reflective layer includes aluminum, silver, gold, chromium, nickel and copper, and the alloy reflective layer includes a nickel-chromium alloy, an aluminum alloy and a titanium alloy.

3. A Fresnel lens layer is manufactured by a roll-to-roll process, the roll-to-roll process including the steps of: applying an adhesive layer onto a substrate, a thin film having a predetermined haze ratio, a diffusion layer or a coloring layer; and carrying out a roll-to-roll embossing technique on the adhesive layer through a mold for manufacturing the Fresnel lens layer to form a Fresnel lens layer; The reflective layer is manufactured by electroplating, vapor deposition, spraying or coating process; The Fresnel lens layer further includes a substrate layer or a thin film having a predetermined haze ratio formed on a bottom surface of the annular protrusion, 3. The method of claim 2, wherein a scattering type microstructure is formed on a surface of the annular protrusion of the Fresnel lens layer.

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