A projection screen, image display system and conical roller

Abstract

The application discloses a projection screen, an image display system and a conical roller, and belongs to the field of projection display. The projection screen is provided with a Fresnel lens layer. The Fresnel lens layer comprises a plurality of Fresnel lens units arranged in the same direction on the plane of the projection screen and having a sawtooth-shaped cross section. The Fresnel lens unit comprises a first surface. The first surface is provided with a light-reflecting material. The light-reflecting material and the first surface form a rough reflection interface. The rough reflection interface is used for accurately controlling the transmission direction of the projection light. The average roughness of the rough reflection interface is greater than 0.1 microns and less than 1 micron. The rough reflection interface is sampled in the thickness direction of the screen. The height data of each sampling point obtained is subjected to reference surface inclination correction. The cumulative proportion (percent) of the frequency of the included angle alpha between the normal line of the micro-morphology of the sampling point on the rough reflection interface and the normal line of the reference plane of the rough reflection interface within 0-19.9 degrees is greater than or equal to 70 percent. The application effectively improves the light energy utilization rate and brightness and reduces the light energy loss.

Description

Technical Field

[0001] This invention belongs to the field of projection display and relates to a projection screen, an image display system, and a tapered roller. Background Technology

[0002] A projection image display system requires a projector and a projection screen. The projection screen's function is to image the light emitted by the projector and redistribute the light intensity of the projected image. Common projection screens use a smooth optical structure with a diffusion layer to distribute the light intensity, or a textured optical structure. When the optical structure is smooth, the projection light only undergoes specular reflection, resulting in uneven light emission and uneven energy distribution, leading to low light energy utilization efficiency. With a textured optical structure, the projection light is diffused relatively evenly in all directions. However, in actual viewing, viewers only need the projection light to be diffused within the viewing area, not necessarily diffused in all directions. These diffused rays, after passing through the textured surface, create numerous rays with large incident angles within the screen's structural layers. These rays undergo multiple total internal reflections and absorption by the coloring layer, resulting in reduced screen brightness, low light energy utilization efficiency, and high light energy loss. Summary of the Invention

[0003] The technical problem to be solved and the technical task proposed by this invention is to improve the existing technology and provide a projection screen. By precisely setting the morphological characteristics of the rough structure of the rough reflective interface on the Fresnel lens unit, the transmission direction of the projection light emitted from the Fresnel lens unit is precisely controlled, which greatly reduces the number of projection light rays that undergo total internal reflection and the number of reflections within the projection screen structure layer. This reduces the amount of projection light rays that are absorbed by the screen structure layer after multiple reflections, thereby improving the brightness and light energy utilization of the projection screen and reducing light energy loss.

[0004] The technical solution of this invention is:

[0005] A projection screen is provided with a Fresnel lens layer for controlling the transmission direction of projected light. The Fresnel lens layer includes a plurality of Fresnel lens units with a serrated cross-section arranged in the same direction on the plane of the projection screen. Each Fresnel lens unit includes a first surface for controlling the transmission direction of projected light. A reflective material is provided on the first surface, and the reflective material forms a rough reflective interface with the first surface. The rough reflective interface is used to precisely control the transmission direction of projected light.

[0006] The average roughness of the rough reflective interface is greater than 0.1 μm and less than 1 μm;

[0007] The rough reflective interface is sampled in the thickness direction of the screen, and the height data of each sampling point is corrected for reference plane tilt. The normal of the reference plane of the rough reflective interface is Z, the normal of the micro-morphology of the sampling point on the rough reflective interface is F, and the angle between the normal of the micro-morphology of the sampling point on the rough reflective interface and the normal of the reference plane of the rough reflective interface is α. The cumulative frequency percentage (%) of the angle α in the range of 0° to 19.9° is 70% or more.

[0008] Wherein: the cumulative percentage of the frequency of the included angle α within 0° to 19.9° is the percentage of the number of micromorphic normals of the sampling points within the included angle α within 0° to 19.9° to the total number of normals of the micromorphic features of all sampling points.

[0009] This invention controls the size and specifications of the rough structure on the rough reflection interface by controlling the roughness of the rough reflection interface on the first surface of the Fresnel lens unit; and further controls the shape of the rough structure (the undulating rough structure can be equivalent to a combination of countless points of different heights under microscopic topographic data sampling, and by precisely controlling the range of the normal direction of each point, the topographic features of the rough structure formed by the combination of points are precisely determined), thereby precisely controlling the range of the transmission direction of the projection light through the rough structure, thus effectively reducing the number of total internal reflections of the projection light in each structural layer inside the projection screen. When the cumulative frequency percentage (%) of the angle α between the normal F of the micro-morphology of the sampling point on the rough reflective interface and the normal Z of the reference plane of the rough reflective interface is 70% or more within the range of 0° to 19.9°, the number of total internal reflections of the projection light rays incident on the Fresnel lens unit after passing through the rough reflective interface of the first surface inside the projection screen is extremely small, and the number of total internal reflections of the projection light rays in each structural layer inside the projection screen is also reduced. Therefore, the amount of projection light rays that are absorbed and lost by the internal structural layers of the projection screen due to multiple total internal reflections is also greatly reduced, thereby improving the light energy utilization rate of the projection screen and reducing light energy loss.

[0010] Furthermore, the vertical height between the top of the protrusion and the bottom of the adjacent depression on the rough reflective interface is greater than 0.05 μm and less than 10 μm.

[0011] Furthermore, the projection screen also includes a substrate, and the Fresnel lens layer is disposed on one surface of the substrate.

[0012] Furthermore, the side of the substrate away from the Fresnel lens layer is a rough surface, which can further enhance the uniformity of the projection light diffusion, so that the image on the screen can be viewed from all directions.

[0013] Furthermore, a color layer is provided between the substrate and the Fresnel lens layer, and a light-absorbing material is added to the color layer.

[0014] Furthermore, the color layer also contains diffusing particles, which can scatter the projected light, thereby further improving the uniformity of the screen's brightness distribution.

[0015] Furthermore, the Fresnel lens units are arranged in a circular arc array, a parabolic array, an elliptical arc array, or a linear array. Different shapes of the Fresnel lens units can meet the needs of viewing images in different viewing scenarios.

[0016] Furthermore, the reflective material has a thickness of 80 nm or more and an average reflectivity of 50% or more for visible light.

[0017] Furthermore, the reflective material is manufactured using a vacuum coating method.

[0018] The present invention also provides an image display system, including any of the above-described projection screens and a projector that projects projection light onto the projection screen. By using the above-described projection screen, the loss of projection light inside the projection screen is reduced, and the light energy utilization rate of the projection screen is improved. To ensure the same display effect, the energy consumption required by the projector is relatively low. When the energy consumption of the projector is the same, the utilization rate of projection light is high, and the display brightness on the projection screen is relatively high, thereby improving the brightness of the projection screen.

[0019] Furthermore, from the edge closest to the projector to the edge furthest from the projector, the average roughness of the rough reflective interface gradually decreases.

[0020] In addition, the present invention also provides a conical roller, wherein a microstructure complementary to the Fresnel lens unit as described in claim 1 is provided on the roller surface of the conical roller, wherein the first surface of the microstructure is a rough surface;

[0021] The average roughness of the rough surface is greater than 0.1 μm and less than 1 μm;

[0022] The rough surface is sampled radially by the conical roller, and the height data of each sampling point is corrected for reference plane tilt. The cumulative percentage (%) of the frequency of the normal of the micromorphology of the sampling point of the rough surface and the normal of the reference plane of the rough surface being within 0° to 19.9° is 70% or more.

[0023] Wherein: the cumulative percentage (%) of the frequency of the angle between the normal of the micromorphology of the sampling point of the rough surface and the normal of the reference plane of the rough surface being within 0° to 19.9° is the percentage of the number of normals of the micromorphology of the sampling point within the angle of 0° to 19.9° to the total number of normals of the micromorphology of all sampling points.

[0024] The conical roller provided by this invention is used to manufacture a Fresnel lens layer comprising a plurality of Fresnel lens units arranged in the same direction with a serrated cross section, providing a basis for the manufacture of the projection screen of this invention.

[0025] Furthermore, from the small end to the large end of the conical roller, the average roughness of the rough surface gradually decreases.

[0026] Furthermore, the vertical height between the top of the protrusion and the bottom of the adjacent depression on the rough surface is 0.05 μm or more and 10 μm or less. Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] The projection screen and image display system of the present invention, by precisely setting the size, shape and other morphological features of the rough structure of the rough reflective interface on the Fresnel lens unit of the projection screen, precisely controls the transmission direction of the projection light emitted from the Fresnel lens unit, greatly reducing the number of projection light rays that undergo total internal reflection and the number of reflections within the projection screen structural layer, reducing the amount of projection light rays that are absorbed by the screen structural layer after multiple reflections, improving the brightness and light energy utilization of the projection screen and reducing light energy loss. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the projection screen of the present invention when it is cut along the arrangement direction of the Fresnel lens unit array;

[0029] Figure 2 This is a schematic diagram of the structure of a projection screen cut along the Fresnel lens unit array arrangement direction, according to another example of the present invention.

[0030] Figure 3 This is an example of the cross-sectional morphology obtained by measuring the Fresnel lens unit on the projection screen of the present invention using a laser microscope;

[0031] Figure 4 This is a schematic diagram used to illustrate the method for calculating surface roughness;

[0032] Figure 5 and Figure 6 This is an example of laser microscopy used to measure the average roughness of the first surface of a Fresnel lens unit;

[0033] Figure 7 This is a schematic diagram of the Fresnel lens unit array of the projection screen sample facing the objective lens;

[0034] Figure 8 yes Figure 7 A schematic diagram of the topography of region Q in the middle region;

[0035] Figure 9 yes Figure 7 Schematic diagram of the morphology of the mid-region after Q correction;

[0036] Figure 10 This is a schematic diagram of each sampling point;

[0037] Figure 11 This is a schematic diagram of the normal F direction of the micro-morphology of each sampling point on the rough reflective interface that controls the direction of projection light transmission, and the normal Z direction of the reference plane.

[0038] Figure 12 It is a statistical diagram of the normal F direction of the micro-morphology of each sampling point on the rough reflective interface that controls the direction of projection light transmission;

[0039] Figure 13 This is a schematic diagram of the included angle α in an embodiment of the projection screen of the present invention;

[0040] Figure 14 This is a frequency statistical histogram of the angle between normal F and normal Z on the projection screen of the present invention;

[0041] Figure 15 This is a cumulative probability distribution diagram of the angle between the normal F and the normal Z on the projection screen of the present invention.

[0042] Figure 16 This is a frequency histogram of a rough reflective interface in which the frequency of the normal F of the micromorphology of the sampling points within the range of [0°, 19.9°] accounts for 99% of the total frequency.

[0043] Figure 17 This is a cumulative probability distribution diagram of a rough reflective interface in which the frequency of the normal F of the micromorphology of the sampling points within the range of [0°, 19.9°] accounts for 99%.

[0044] Figure 18 This is a frequency histogram of a rough reflective interface in which the frequency of the normal F of the micromorphology of the sampling points within the range of [0°, 19.9°] accounts for 86% of the total frequency.

[0045] Figure 19 This is a cumulative probability distribution diagram of a rough reflective interface in which the frequency of the normal F of the micromorphology of the sampling points within the range of [0°, 19.9°] accounts for 86%.

[0046] Figure 20This is a frequency histogram of a rough reflective interface in which the frequency of the normal F of the micromorphology of the sampling points within the range of [0°, 19.9°] accounts for 70% of the total frequency.

[0047] Figure 21 This is a cumulative probability distribution diagram of a rough reflective interface in which the frequency of the normal F of the micromorphology of the sampling points within the range of [0°, 19.9°] accounts for 70%.

[0048] Figure 22 This is a frequency histogram of a rough reflective interface in which the frequency of the normal F of the micromorphology of the sampling points within the range of [0°, 19.9°] accounts for 52% of the total frequency.

[0049] Figure 23 This is a cumulative probability distribution diagram of a rough reflective interface in which the frequency of the normal F of the micromorphology of the sampling points within the range of [0°, 19.9°] accounts for 52%.

[0050] Figure 24 This is a schematic diagram of the arrangement shape of the Fresnel lens units according to an embodiment of the present invention;

[0051] Figure 25 This is a schematic diagram showing the vertical height between the protruding top and the adjacent recessed bottom of the rough reflective interface in an embodiment of the present invention.

[0052] Figure 26 This is a schematic diagram of an image display system according to an embodiment of the present invention;

[0053] Figure 27 This is a schematic diagram of a conical roller according to an embodiment of the present invention.

[0054] In the picture:

[0055] 10-Projection screen; 20-Projection system; 101-Fresnel lens layer; 102-Substrate; 103-Reflective material; 104-Cone roller; 1041-Microstructure; 1011-Fresnel lens unit; 1012-First surface; 1013, 1014-Rough reflective interface; 105-Rough surface; G-Projection ray; Y-Projector. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The accompanying drawings of the embodiments of the present invention are merely corresponding schematic diagrams, and their scale, size, and other features differ from the actual figures. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Existing technologies describe common projection screens that use a smooth optical structure with a diffusion layer to distribute image light intensity, or a textured optical structure to distribute image light intensity. When the optical structure is smooth, it only produces specular reflection of the projected light, resulting in uneven light emission and uneven energy distribution on the screen, leading to low light energy utilization efficiency. Conversely, with a textured optical structure, the uncontrollable shape causes a large amount of projected light reflected by the optical structure layer to undergo multiple total internal reflections and absorption by the coloring layer within the screen's structural layers, resulting in reduced screen brightness, low light energy utilization efficiency, and high light energy loss.

[0058] To solve the above problems, Figure 1 This is a schematic diagram of the structure of the projection screen when it is cut along the Fresnel lens unit array arrangement direction according to an embodiment of the present invention, as shown below. Figure 1 As shown in Figure a, the projection screen 10 is provided with a Fresnel lens layer 101 for controlling the transmission direction of the projected light. The Fresnel lens layer 101 includes a plurality of Fresnel lens units 1011 arranged in the same direction on the plane of the projection screen with a serrated cross-section. Each Fresnel lens unit 1011 includes a first surface 1012 for controlling the transmission direction of the projected light. The first surface has a straight cross-section and is provided with a reflective material 103. In addition, the other surfaces of the serrated Fresnel lens unit, except for the first surface 1012, are preferably rough surfaces. This can reduce the amount of ambient light incident on these surfaces being reflected onto the first surface 1012 and interfering with the image formation of the projected light. The Fresnel lens layer 101 is integrally formed with the substrate, so there is no clear boundary between the Fresnel lens layer and the substrate.

[0059] Optionally, one embodiment of the projection screen, such as Figure 1As shown in Figure b, a Fresnel lens layer 101 for controlling the transmission direction of projected light is disposed on the projection screen 10. The Fresnel lens layer 101 includes a plurality of Fresnel lens units 1011 arranged in the same direction on the plane of the projection screen with a serrated cross-section. Each Fresnel lens unit 1011 includes a first surface 1012 for controlling the transmission direction of projected light. The cross-sectional shape of the first surface is arc-shaped, and a reflective material 103 is disposed on the first surface. In addition, the other surfaces of the serrated Fresnel lens unit, except for the first surface 1012, are preferably rough surfaces. This can reduce the reflection of ambient light incident on these surfaces onto the first surface 1012, which interferes with the imaging of the projected light. The Fresnel lens layer 101 is integrally formed with the substrate, so there is no clear boundary between the Fresnel lens layer and the substrate. Furthermore, the cross-sectional shape of the first surface of the Fresnel lens unit can also be a higher-order curve or other shapes. However, as long as the function is to control the transmission direction of projected light and meet the needs of the application scenario, they all fall within the protection scope of this invention. Examples will not be listed here.

[0060] Figure 2 This is a schematic diagram of the structure of a projection screen cut along the Fresnel lens unit array arrangement direction, representing another example of the present invention. Figure 2 As shown in Figure a, the projection screen 10 has a supporting substrate 102, and a Fresnel lens layer 101 for controlling the direction of projection light transmission is disposed on one surface of the substrate 102. The Fresnel lens layer 101 includes a plurality of Fresnel lens units 1011 arranged in the same direction on the plane of the projection screen with a sawtooth cross-section. The Fresnel lens unit 1011 includes a first surface 1012 for controlling the direction of projection light transmission. A reflective material 103 is disposed on the first surface 1012. The interaction between the reflective material 103 and the first surface 1012 forms two rough reflective interfaces 1013 and 1014. Figure 2As shown in the enlarged view of the first surface of the Fresnel lens unit in Figure a, a rough reflective interface 1013 is formed between the first surface 1012 of the Fresnel lens unit 1011 and the reflective material 103. A rough reflective interface 1014 is formed on the other surface of the reflective material 103 away from the first surface 1012 of the Fresnel lens unit 1011. In this screen structure, the projected light G entering the screen from the surface of the substrate 102 is reflected at the rough reflective interface 1013. The morphology of the rough reflective interface 1013 determines the transmission direction of the reflected light, thus effectively utilizing the projected light. It should be noted that in this screen structure, since the rough reflective interface 1013 controls the transmission direction of the projected light, subsequent morphological testing and feature analysis of the rough reflective interface 1013 refers to the morphological testing and feature analysis of the rough reflective interface 1013 itself, and the subsequent feature analysis should be based on the morphological data of the rough reflective interface 1013. Further explanation: the rough reflective interface 1013 is formed by the rough structure of the first surface 1012 of the Fresnel lens unit 1011 and the reflective material 103. Additionally, the surfaces of the serrated Fresnel lens unit 1011 other than the first surface 1012 are preferably rough surfaces. This reduces the amount of ambient light incident on these surfaces being reflected back onto the first surface 1012 and interfering with the projection light imaging. The Fresnel lens layer 101 is bonded to the substrate 102, and there is a clear boundary between the Fresnel lens layer 101 and the substrate 102. Of course, the Fresnel lens layer 101 can also be integrally formed with the substrate 102.

[0061] Furthermore, such as Figure 2 As shown in Figure b, a substrate 102 supporting the projection screen 10 is provided on the projection screen 10, and a Fresnel lens layer 101 for controlling the direction of projection light transmission is provided on one surface of the substrate 102. The Fresnel lens layer 101 includes a plurality of Fresnel lens units 1011 with a serrated cross-section arranged in the same direction on the plane of the projection screen. The Fresnel lens unit 1011 includes a first surface 1012 for controlling the direction of projection light transmission. A reflective material 103 is provided on the first surface 1012, and the interaction between the reflective material 103 and the first surface 1012 forms two rough reflective interfaces 1013 and 1014. Figure 2 As shown in the enlarged view of the first surface of the Fresnel lens unit in Figure b, a rough reflective interface 1013 is formed on the first surface 1012 of the Fresnel lens unit 1011 between it and the reflective material 103. A rough reflective interface 1014 is formed on the other surface of the reflective material 103, away from the first surface 1012 of the Fresnel lens unit 1011. In this screen structure, the incident projection light G... Figure 2The screen structure shown in Figure b is merely a schematic diagram illustrating one possible screen structure with a rough reflective interface. More often, from the incident direction of the projected light G, other structural layers (such as a filling layer, color layer, diffusion layer, substrate, etc.) can be placed on the projection screen and reflected onto the rough reflective interface 1014. The morphology of the rough reflective interface 1014 determines the transmission direction of the reflected light, thus effectively utilizing the projected light. It should be noted that in this screen structure, since the rough reflective interface 1014 controls the transmission direction of the projected light, subsequent morphological testing and feature analysis of the rough reflective interface 1014 refers to the morphological testing and feature analysis of the rough reflective interface 1014 itself, and the subsequent feature analysis must be based on the morphological data of the rough reflective interface 1014. Further explanation: the rough reflective interface 1014 can be formed by a reflective material 103 of uneven thickness distributed on the first surface 1012 of the Fresnel lens unit 1011, or it can be formed by the rough structure of the first surface 1012 of the Fresnel lens unit 1011 and the reflective material 103 together. Furthermore, the surfaces of the serrated Fresnel lens unit, except for the first surface 1012, are preferably rough surfaces. This reduces the amount of ambient light incident on these surfaces being reflected back onto the first surface 1012 and interfering with the projection light imaging. The Fresnel lens layer 101 is bonded to the substrate 102, and there is a clear boundary between the Fresnel lens layer 101 and the substrate 102. Of course, the Fresnel lens layer 101 can also be integrally formed with the substrate 102.

[0062] Further explanation: the cross-sectional shape of the first face 1012 can also be an arc, a higher-order curve, or other shapes.

[0063] Further explanation: the arrangement direction of the Fresnel lens unit array can be understood as... Figure 24 The arrows in diagram a indicate the direction.

[0064] Furthermore, the substrate 102, serving as the projection screen, needs to achieve a more suitable frontal brightness. Therefore, the substrate 102 is preferably translucent, and in terms of the screen's rollability, the substrate is preferably composed mainly of resin. Examples of resins include cured forms of curable resins and thermoplastic resins. For the screen's flexibility, thermoplastic resins are preferred. Examples of thermoplastic resins include: polyethylene terephthalate (PET), polyethylene naphthalate, polycarbonate, polyether sulfone, and polyolefin. One type of resin or a combination of two or more resins can be used.

[0065] As a further supplementary explanation, the substrate 102 may be made of materials including but not limited to the following: flexible plastic or rubber materials such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, casein phosphopeptide, biaxial polypropylene, polyamide, polyurethane, polymethyl methacrylate, thermoplastic polyurethane elastomer, or transparent substrates with a certain degree of rigidity such as glass, acrylic, and ceramics.

[0066] As a further explanation, the materials of the Fresnel lens layer 101 include, but are not limited to, radiation-curable resin, thermosetting resin, and reactive curing resin. The Fresnel lens layer 101 is made using the above-mentioned raw materials as follows: the raw materials are transferred and coated onto the substrate material using a roller mold for making microlenses to form the Fresnel lens layer 101; or the substrate layer and the Fresnel lens layer 101 are fused into one layer by hot pressing using a roller mold for making microlenses.

[0067] Furthermore, the substrate 102 in the projection screen can be a single layer or multiple layers. When the substrate 102 is composed of multiple layers, it can be formed by alternately layering two transparent resin layers with different refractive indices. When the main component of the substrate 102 is resin, more suitable relative frontal brightness and other aspects can be obtained. The thickness of the substrate 102 is preferably 75 μm or more and 2000 μm or less, more preferably 100 μm or more and 1000 μm or less, further preferably 100 μm or more and 500 μm or less, and particularly preferably 100 μm or more and 300 μm or less.

[0068] Furthermore, regarding the imaging and uniformity of the projection screen, the side of the substrate 102 away from the Fresnel lens layer 101 is preferably a textured surface. The light scattering characteristics of the textured surface structure can further enhance the uniformity of the projection light diffusion, so that viewers can see an image with consistent brightness on the projection screen from all directions.

[0069] Further explanation: the textured surface of the substrate can scatter light isotropically or anisotropically. This needs to be set according to the usage scenario of the projection screen. Generally, for scenarios where there is a need to view from all directions, the textured surface is preferably isotropically scattering. For home viewing scenarios, the textured surface is preferably horizontally scattering more than vertically scattering, which is conducive to multiple people watching.

[0070] Further explanation: The rough surface can be formed directly on the surface of the substrate 102 after roughening treatment. The roughening treatment methods include sandblasting or roughening the mold surface and then transferring the structure with adhesive or spraying adhesive containing diffusion particles.

[0071] As a further explanation, the textured surface can also be made with microstructures, which are used to increase the diffusion angle of the projection screen, making the horizontal diffusion angle of the projection screen greater than the vertical diffusion angle of the projection screen, or to enhance the diffusion ability of some areas of excessive brightness on the projection screen, reduce the brightness of the excessively bright areas, and improve the brightness uniformity of the projection screen.

[0072] As a supplementary explanation, the surface of the substrate 102 away from the Fresnel lens layer 101 can also be a smooth surface. In this case, an anti-reflective material can be applied to the smooth surface, such as an anti-reflective film composed of high and low refractive index materials, to reduce the reflection loss of obliquely incident projection light, enhance the display brightness of the projection screen, and obtain ultra-high definition images. Alternatively, microstructures with a horizontal diffusion angle greater than the vertical diffusion angle can be applied to the smooth surface, making the horizontal viewing angle of the projection screen larger and obtaining a wider horizontal viewing field. Microstructures with anisotropic diffusion angles can also be applied to the smooth surface, that is, the diffusion ability of the microstructures is different in different directions. The microstructures can be set accordingly according to the different brightness of different positions on the projection screen. The diffusion angle of the microstructure is large at the position of high brightness of the projection screen to reduce brightness, and the diffusion angle of the microstructure is small at the position of low brightness to ensure that the brightness is not reduced, thereby improving the uniformity of the display brightness of the projection screen and increasing the effective viewing angle.

[0073] Furthermore, a color layer is provided between the substrate 102 and the Fresnel lens layer 101. The color layer contains light-absorbing materials, including but not limited to various pigments, dyes, carbon black, black iron oxide, etc., which mainly serve to filter and adjust the color.

[0074] Furthermore, a light-absorbing material that can absorb unwanted light, such as a light-absorbing material that absorbs ambient light, can be provided inside the substrate 102 to selectively transmit the desired light and achieve the effect of filtering and color adjustment.

[0075] As a further explanation, a light-diffusing material containing diffusing particles may also be provided in the substrate 102 to enhance the scattering angle of light inside the projection screen and make the brightness display of the projection screen more uniform.

[0076] Furthermore, a diffusion layer and a coloring layer can be disposed between the substrate 102 and the Fresnel lens layer 101. The diffusion layer and the coloring layer can be independent of each other, and the arrangement positions of the layers can be interchanged. Alternatively, the diffusion layer and the coloring layer can be integrated into one unit, that is, the diffusion layer and the coloring layer are a whole layer, which has the function of both the coloring layer and the diffusion layer.

[0077] As a further explanation, diffusion particles and resin material can be disposed within the diffusion layer. The diffusion particles can be uniformly distributed within the diffusion layer or randomly distributed. The diffusion particles scatter light passing through the diffusion layer. To achieve more uniform light scattering and intensity distribution, it is preferable that the diffusion particles are uniformly distributed within the diffusion layer. The diffusion particles include, 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, and magnesium fluoride particles, with a preferred particle size of 5 nm to 200 nm.

[0078] As a further explanation, the diffusion layer can be configured as a single-layer arc-shaped columnar microlens structure or a multi-layer arc-shaped columnar microlens structure. The arc-shaped surface of the arc-shaped columnar microlens diffuses the light, thereby increasing the viewing field of the projection screen and improving the uniformity of display brightness.

[0079] As a further explanation, light-absorbing materials and resin materials can be set inside the coloring layer. The light-absorbing materials can absorb unwanted light such as ambient light and selectively transmit the desired light, thus playing the role of filtering and color adjustment. The light-absorbing materials include, but are not limited to, various pigments, dyes, carbon black, black iron oxide, etc.

[0080] As a further supplementary explanation, a structural layer may also be provided between the substrate 102 and the Fresnel lens layer 101, with light-absorbing material and diffusion particles disposed inside the structural layer, or light-absorbing material and diffusion microstructure disposed inside the structural layer, or light-absorbing material, diffusion particles and diffusion microstructure disposed inside the structural layer, to further improve the contrast of the projection screen.

[0081] Furthermore, Figure 24 This is a schematic diagram of the Fresnel lens unit arrangement according to an embodiment of the present invention, as shown below. Figure 24 As shown in Figure a, the Fresnel lens units 1011 in the Fresnel lens layer 101 are arranged in an arc-shaped array on the projection screen plane; as shown in Figure a. Figure 24 As shown in Figure b, the Fresnel lens units 1011 are arranged in an elliptical arc array; as Figure 24 As shown in Figure c, the Fresnel lens units 1011 are arranged in a parabolic array. In the three cases mentioned above, since the arrangement of the Fresnel lens units 1011 is non-linear, it is often described using Fresnel lens unit loops, which will also be referred to as loops in the following text. Figure 24As shown in Figure d, the Fresnel lens units 1011 are arranged in a linear array. In addition to the four cases mentioned above, other array shapes can also be set. No matter how the array shape of several Fresnel lens units 1011 in the Fresnel lens layer 101 is set, the purpose is to refract or reflect the image light to the required viewing area to meet the needs of viewing images in different viewing scenarios.

[0082] Furthermore, the thickness of the reflective material 103 on the projection screen is greater than or equal to 80 nm. If the thickness of the reflective material 103 is less than 80 nm, the light reflectivity will be less than 50%, resulting in very low brightness on the projection screen, which is not conducive to normal viewing. The reflective material 103 is generally formed using methods such as printing, spraying, or vacuum coating. Preferably, in order to precisely control the thickness of the reflective material 103, it is manufactured using vacuum coating. Preferably, the reflective material 103 is a metal, such as aluminum or chromium. More preferably, an isolation layer is provided on the outer surface of the metal reflective material to isolate it from the air and prevent oxidation, corrosion, or other damage to its reflective properties. The isolation layer is preferably an oxide medium material such as silicon dioxide or aluminum oxide, or a resin material such as thermosetting, radiation-curing, or reaction-curing resin.

[0083] As a further explanation, the reflective material 103 can be configured to have a certain degree of light transmittance, preferably with an average reflectance of visible light greater than or equal to 50%. If the reflectance is too low, the brightness of the projection screen will be too low, which is not conducive to normal image viewing. The reflective material 103 has a certain degree of transmittance, allowing ambient light entering the projection screen to pass through the reflective material, preventing ambient light from being reflected to the viewing area. Pigments or dyes that can reflect red, green, and blue light and absorb / transmit other colors of visible light can also be added to the reflective material 103 to absorb more ambient light. Both of these methods effectively improve the contrast of the projection screen.

[0084] Furthermore, in this embodiment of the invention, the projection screen can also have a black backplate on the side of the reflective material 103 away from the Fresnel lens layer 101. The black backplate can be precisely bonded to the reflective layer with double-sided tape or EVA hot melt adhesive to serve as a substrate, providing support and protection for the projection screen and facilitating subsequent installation. A black coating can also be applied to the surface of the black backplate to absorb unwanted light, such as ambient light, incident on it, thus appropriately improving the contrast of the projection screen. A hanging bracket can also be provided on the side of the black backplate away from the reflective layer. The bracket can be fixed to the corresponding position on the black backplate by double-sided tape or screws, facilitating subsequent installation. Alternatively, a magnetic material can be used instead of the hanging bracket to allow the projection screen to be installed on the wall via magnetic adsorption, maintaining the aesthetics of the wall.

[0085] Furthermore, in this embodiment of the invention, a decorative border can be provided around the projection screen to wrap around the layers of the projection screen in the thickness direction, so as to fix and beautify the appearance of the projection screen and divide it into projection display areas.

[0086] The following description further elaborates on the rough reflection interface on the first surface of the Fresnel lens unit, the calculation of the average roughness of the rough reflection interface, the angle α between the normal F of the micro-morphology of the sampling point on the rough reflection interface and the normal Z of the reference plane of the rough reflection interface, and the probability statistics of the normal F of the micro-morphology of each sampling point on the rough reflection interface within a certain range of the angle α.

[0087] Rough reflective interface on the first surface of the Fresnel lens unit

[0088] The morphology testing method for the rough reflective interface (the rough reflective interface that controls the direction of projection light transmission) on the first surface of the Fresnel lens unit is as follows: Select a microscope that can test the 3D morphology of the sample and export the image data, preferably one with built-in data analysis capabilities; prepare the screen sample to be tested, cut a small sample of the screen at any position on the projection screen, and place the Fresnel lens unit array facing the microscope objective (Note: when the projection screen is like...). Figure 2 As shown in Figure a, when the rough reflective interface 1013 is in operation, the reflective material on the Fresnel lens unit needs to be removed in order to test the morphology of the rough reflective interface 1013; while when the projection screen is like... Figure 2As shown in Figure b, when the rough reflective interface 1014 is in function, if other screen structure layers exist near the incident light ray G, these other structure layers also need to be removed before the morphology of the rough reflective interface 1014 can be tested. A microscope is used to magnify and sample the screen sample, obtaining a clear 3D morphology of the rough reflective interface on the first surface of the Fresnel lens unit that controls the direction of projection light transmission. The interval between sampling points in the acquired microscopic image should not exceed 0.3 μm, and the number of sampled data points should be greater than or equal to 1024*768. After sampling, discrete height data of the 3D morphology of the rough reflective interface on the first surface of the Fresnel lens unit on the screen sample under the corresponding microscopic viewing field are obtained. Analysis software can then be used to analyze the roughness, height, depth, and other morphological values ​​of the rough reflective interface on the first surface of the Fresnel lens unit on the screen sample. It should be noted that due to limitations in manufacturing processes and sampling methods, before analyzing and calculating the sampled data of the Fresnel lens unit, it is necessary to trim off the deformed portions at the top and bottom of the first surface of the Fresnel lens unit (the top and bottom of the first surface of the Fresnel lens unit are severely distorted due to the abrupt change in height, making it impossible to reflect the true morphological data, so the deformed areas need to be trimmed off), retaining the data from the middle 80% area of ​​the first surface of a single Fresnel lens unit. Therefore, when measuring the average roughness of a rough reflective interface, it is preferable to use the data from the middle 80% area of ​​the first surface of the Fresnel lens unit. For example, for a Fresnel lens unit with a pitch of 100 μm, only the sampled data from the area smaller than 80 μm in the middle is selected.

[0089] like Figure 3 To illustrate the cross-sectional morphology obtained by measuring Fresnel lens units on a projection screen using a laser microscope, a 3D laser microscope (KEYENCE VK-X1050) was used. With the objective lens at 100x magnification, the Fresnel lens structure surface of the sample was positioned directly opposite the objective lens, with the Fresnel lens unit 1011 array arrangement direction as the horizontal orientation. After obtaining the microscopic image, linear calibration was directly performed using the KeyENCE microscope's analysis software. Figure 3 The diagram shows the cross-sectional topography of a rough reflective interface on the first surface 1012 of a Fresnel lens unit.

[0090] Calculation of average roughness of rough reflective interface

[0091] A schematic diagram of the average roughness of a rough reflective interface is shown below. Figure 4 As shown, the roughness of the rough reflective interface is denoted as Ra. The cross-sectional morphology curve is obtained by microscopic testing. A certain reference length lr is selected from the morphology curve, and the height data Z(x) of the morphology within this reference length is statistically analyzed. The calculation formula is as follows:

[0092]

[0093] lr is the reference length, and Z(x) is the height of each data point on the reference length.

[0094] In order for the calculated roughness data to more accurately reflect the roughness characteristics of the rough reflective interface on the first surface 1012 of the Fresnel lens unit that controls the transmission direction of the projected light rays, it is necessary to select multi-line calibration in the microscope test pattern of the Fresnel lens unit 1011, thereby calculating multiple roughness values ​​using the above formula, and then taking the arithmetic mean of the multiple roughness values ​​to obtain the average roughness of the rough reflective interface on the first surface of the Fresnel lens unit that controls the transmission direction of the projected light rays.

[0095] Specifically, the above process can be illustrated by the following steps for obtaining the average roughness directly using the Keyence microscope's analysis software: In the Keyence VK-X1050 microscope's analysis software, open the microscopic image of the Fresnel lens unit 1011 tested at 100x objective. In the right sidebar of the analysis software, select Vertical Line, select Measurement Method—Multi-line Roughness, set the number of lines in the range to 30 measurement lines, set the interval to 20 pixels, set the cutoff value λc to 0.25mm, and click OK to directly obtain the average roughness value of the 30 roughness values ​​from the analysis software.

[0096] like Figure 5 and Figure 6As shown, the average roughness of the rough reflective interface on the first surface of the Fresnel lens unit, which controls the direction of projection light transmission, obtained by measuring the cross-sectional morphology curve of the first surface of any Fresnel lens unit on the projection screen using Keyence microscope analysis software according to the aforementioned operation, is 0.1 μm or more, preferably 0.16 μm or more, more preferably 0.23 μm or more, even more preferably 0.28 μm or more, and even more preferably 0.36 μm or more. In addition, the average roughness of the rough reflective interface on the first surface of the Fresnel lens unit, which controls the direction of projection light transmission, obtained by measuring the cross-sectional morphology curve of the first surface of any Fresnel lens unit on the projection screen, is 1 μm or less, preferably 0.8 μm or less, more preferably 0.6 μm or less, and even more preferably 0.48 μm or less. Furthermore, the vertical height between the top of the protrusion and the bottom of the adjacent depression of the rough reflective interface on the first surface of the Fresnel lens unit, which controls the direction of projection light transmission, obtained from the cross-sectional morphology curve of the first surface measured by any Fresnel lens unit on the projection screen, is 0.05 μm or more, preferably 0.1 μm, more preferably 0.3 μm, further preferably 0.5 μm, and even more preferably 1 μm; and the vertical height between the top of the protrusion and the bottom of the adjacent depression of the rough reflective interface on the first surface of the Fresnel lens unit, which controls the direction of projection light transmission, obtained from the cross-sectional morphology curve of the first surface measured by any Fresnel lens unit on the projection screen, is 10 μm or less, preferably 8 μm, more preferably 6 μm, further preferably 5 μm, and even more preferably 3 μm. Assuming the average roughness of the rough reflective interface on the first surface of the Fresnel lens unit is 0.1 μm or more and 1 μm or less, if the vertical height between the top of the protrusion and the bottom of the adjacent recess of the rough reflective interface on the first surface of the Fresnel lens unit that controls the direction of projection light transmission is above the lower limit of the range, then by coordinating with the vertical height between the top of the protrusion and the bottom of the adjacent recess of the rough reflective interface on the first surface of the Fresnel lens unit that controls the direction of projection light transmission, the morphology of the rough reflective interface can be further controlled, so that the transmission direction of the projection light passing through the rough reflective interface is precisely controlled towards the viewing area, thereby obtaining high image brightness. Assuming the average roughness of the rough reflective interface on the first surface of the Fresnel lens unit, which controls the direction of projection light transmission, is between 0.1 μm and 1 μm, and if the vertical height between the top of the protrusion and the bottom of the adjacent recess on the rough reflective interface on the first surface of the Fresnel lens unit, which controls the direction of projection light transmission, is below the upper limit of the range, then by coordinating with the vertical height between the top of the protrusion and the bottom of the adjacent recess on the rough reflective interface on the first surface of the Fresnel lens unit, the amount of projection light lost due to total internal reflection inside the projection screen can be suppressed, thereby achieving lower projection light loss and higher energy utilization efficiency.

[0097] Furthermore, such as Figure 26 The diagram illustrates an image display system in which the average roughness of the rough reflective interface controlling the direction of projection light transmission on the first surface of the Fresnel lens unit on the projection screen 10 gradually decreases from the edge closest to the projector towards the edge furthest from the projector. When the image display system is ceiling-mounted, the average roughness of the rough reflective interface controlling the direction of projection light transmission on the first surface of the Fresnel lens unit on the projection screen 10 still gradually decreases from the edge closest to the projector towards the edge furthest from the projector; when the projector and the Fresnel lens layer are located on the same side, the average roughness of the rough reflective interface controlling the direction of projection light transmission on the first surface of the Fresnel lens unit on the projection screen 10 still gradually decreases from the edge closest to the projector towards the edge furthest from the projector.

[0098] The vertical height between the raised top and the adjacent recessed bottom of the rough reflective interface that controls the direction of projected light transmission is obtained in the following manner:

[0099] The method for testing the vertical height between the convex top and the adjacent concave bottom of the rough reflective interface on the first surface of the Fresnel lens unit, which controls the direction of projection light transmission, is as follows: Select a microscope that can test the 3D morphology of the sample and export the image data, preferably one with built-in data analysis capabilities; prepare the screen sample to be tested, cut a small sample of the screen at any position on the projection screen, and place the Fresnel lens facing the microscope objective (Note: when the projection screen is like...). Figure 2 As shown in Figure a, when the rough reflective interface 1013 is in operation, the reflective material on the Fresnel lens unit needs to be removed in order to test the morphology of the rough reflective interface 1013; while when the projection screen is like... Figure 2As shown in Figure b, when the rough reflective interface 1014 is in function, if there are other screen structure layers near the incident light ray G, these other structure layers also need to be removed before the morphology of the rough reflective interface 1014 can be tested. A microscope is used to magnify and sample the screen sample to obtain a clear 3D morphology of the rough reflective interface controlling the direction of projection light transmission on the first surface of the Fresnel lens unit. The interval between sampling points in the acquired microscopic image should not exceed 0.3 μm, and the number of sampled data points should be greater than or equal to 1024*768. After sampling, discrete height data of the 3D morphology of the rough reflective interface controlling the direction of projection light transmission on the first surface of the Fresnel lens unit on the screen sample under the corresponding microscopic viewing field are obtained. Microscope-matched analysis software or other data processing software is used to perform cross-sectional and measurement analysis on the sampled data to obtain the vertical height between the top of the protrusion and the bottom of the adjacent depression of the rough reflective interface controlling the direction of projection light transmission on the first surface of the Fresnel lens unit. It should be noted that due to limitations in manufacturing processes and sampling methods, before analyzing and calculating the sampled data of the Fresnel lens unit, it is necessary to trim off the deformed portions at the top and bottom of the first surface of the Fresnel lens unit (the top and bottom of the first surface of the Fresnel lens unit are severely distorted due to the abrupt change in height, making it impossible to reflect the true morphological data, so the deformed areas need to be trimmed off), retaining the data from the middle 80% area of ​​the first surface of a single Fresnel lens unit. Therefore, when measuring the vertical height between the top of a protrusion and the bottom of an adjacent depression, it is preferable to use the data from the middle 80% area of ​​the first surface of the Fresnel lens unit. For example, for a Fresnel lens unit with a pitch of 100 μm, only the sampled data from the area smaller than 80 μm in the middle is selected.

[0100] Specifically, taking the use of a 3D laser microscope (KEYENCE VK-X1050) to test the vertical height between the top of a protrusion and the bottom of an adjacent depression as an example, at 100x objective, the Fresnel lens unit array on the sample is projected onto the screen, facing the objective, with the Fresnel lens unit 1011 array arrangement direction as the horizontal direction. A microscopic image is obtained. Then, in the analysis software of the KEYENCE VK-X1050 microscope, the microscopic image of the Fresnel lens unit 1011 tested at 100x objective is opened. On the right side of the analysis software, the contour option is selected to enter the analysis interface. Under the contour tool option on the upper right side of the interface, the contour line is selected—the vertical line is selected. The position of the vertical line is determined on the Fresnel lens microscopic image (i.e., the first surface of the Fresnel lens unit is cut open to obtain the morphology curve of the first surface section). Then, from the measurement tool option on the lower right side of the interface, the point-to-point option is selected, and then the vertical distance is selected. Finally, the top of the protrusion and the bottom of the adjacent depression are determined on the contour line of the microscopic image on the left. The analysis software can then directly obtain the vertical distance. Figure 25 The vertical height h value between the convex top and the adjacent concave bottom of the rough reflective interface shown.

[0101] The average roughness of the rough reflective interface on the first surface of the Fresnel lens unit, which controls the direction of projection light transmission, depends on the average roughness of the Fresnel lens unit on the tapered roller, as described later. The average roughness of the Fresnel lens unit on the tapered roller can be adjusted by setting the manufacturing conditions of the tapered roller, etc.

[0102] In this invention, the height data of each sampling point obtained by sampling the rough reflective interface controlling the transmission direction of the projection light on the projection screen in the thickness direction are corrected for reference plane tilt. Let Z be the normal of the reference plane of the rough reflective interface, F be the normal of the micro-morphology of the sampling point on the rough reflective interface, and α be the angle between the normal F of the micro-morphology of the sampling point on the rough reflective interface and the normal Z of the reference plane of the rough reflective interface. The cumulative percentage (%) of the frequency of the angle α within 0° to 19.9° is 70% or more. Wherein, the cumulative percentage (%) of the frequency of the angle α within 0° to 19.9° is the percentage of the number of normals of the micro-morphology of the sampling point within the angle α within 0° to 19.9° to the total number of normals of the micro-morphology of all sampling points. Specifically, the cumulative frequency percentage (%) is determined using the aforementioned method for testing the morphology of the rough reflective interface controlling the direction of projection light transmission on the first surface of the Fresnel lens unit. This involves obtaining height data of the microscopic morphology of all sampling points within a sampling area on the rough reflective interface controlling the direction of projection light transmission through microscopic sampling. Then, the height data of the plane closest to all these sampling points is calculated using the least squares method (a mathematically known method). Using this plane as a reference plane, the height data of the microscopic morphology of all sampling points on the rough reflective interface are recalculated (reference plane tilt correction), thus obtaining the rough reflective interface... The reference plane of the surface and the micro-morphology of each sampling point of the rough reflective interface corresponding to the reference plane are determined. After the reference plane is determined, the normal Z of the reference plane of the rough reflective interface is also determined. Then, the normal F of the micro-morphology of each sampling point is obtained by the method of calculating the normal F of the micro-morphology of the sampling point on the rough reflective interface. Then, the angle α between the normal F of the micro-morphology of the sampling point on the rough reflective interface and the normal Z of the reference plane of the rough reflective interface is counted. Finally, the percentage of the number of normals of the micro-morphology of the sampling point with the angle α in the range of 0° to 19.9° is calculated out of the total number of normals of the micro-morphology of all sampling points.

[0103] More specifically, the normal F of the micromorphology of each sampling point on the rough reflective interface is obtained in the following manner.

[0104] The test method for the normal F of the microstructure of each sampling point on the rough reflective interface controlling the direction of projection light transmission on the first surface of the Fresnel lens unit is as follows: Select a microscope that can test the 3D morphology of the sample and export the image data, preferably one with built-in data analysis function; prepare the screen sample to be tested, cut a small sample of the screen at any position on the projection screen, and place the Fresnel lens unit array facing the microscope objective (Note: when the projection screen is like...). Figure 2 As shown in Figure a, when the rough reflective interface 1013 is in operation, the reflective material on the Fresnel lens unit needs to be removed in order to test the morphology of the rough reflective interface 1013; while when the projection screen is like... Figure 2As shown in Figure b, when the rough reflective interface 1014 is in function, if other screen structure layers exist near the incident light ray G, these other structure layers also need to be removed before the morphology of the rough reflective interface 1014 can be tested. A microscope is used to magnify and sample the screen sample to obtain a clear 3D morphology of the rough reflective interface on the first surface of the Fresnel lens unit. The interval between sampling points in the acquired microscopic image should not exceed 0.3 μm, and the number of sampled data points should be greater than or equal to 1024*768. After sampling, the height data of the microscopic morphology of the sampling points of the rough reflective interface controlling the direction of projection light transmission on the first surface of the Fresnel lens unit on the screen sample under the corresponding microscopic viewing field is obtained. Then, the height data of the plane closest to all these sampling points is obtained by using the least squares method (a well-known mathematical method that can eliminate the interference of the shape of the first surface of the Fresnel lens unit on the height data, thereby obtaining the data of the rough reflective interface morphology. For example, the cross-sectional shape of the first surface of the Fresnel lens unit mentioned above is arc-shaped, which will interfere with the data of the rough reflective interface morphology). The height data of the plane is then calculated using this plane as a reference plane (reference plane tilt correction). This yields the reference plane of the rough reflective interface and the microscopic morphology of the sampling points of the rough reflective interface corresponding to the reference plane. After the reference plane is determined, the normal Z of the reference plane is also determined. Then, the normal F of the microscopic morphology of each sampling point of the rough reflective interface controlling the direction of projection light transmission on the first surface of the Fresnel lens unit on the screen sample can be calculated using the neighborhood matrix data processing method described below. It should be noted that due to limitations in manufacturing processes and sampling methods, before analyzing and calculating the sampled data of the Fresnel lens unit, it is necessary to trim off the deformed portions at the top and bottom of the first surface of the Fresnel lens unit (the top and bottom of the first surface of the Fresnel lens unit are severely distorted due to the abrupt change in height, making it impossible to reflect the true morphological data, so the deformed areas need to be trimmed off), retaining the data from the middle 80% area of ​​the first surface of a single Fresnel lens unit. Therefore, when measuring the normal F of the micromorphology of each sampling point on the rough reflective interface, it is preferable to take the data from the middle 80% area of ​​the first surface of the Fresnel lens unit. For example, for a Fresnel lens unit with a pitch of 100 μm, only the sampling data from the middle area less than 80 μm is selected. Another method for testing the morphology of the rough reflective interface on the first surface of the Fresnel lens unit is to tilt the screen sample appropriately, flatten the first surface, and align the first surface directly with the microscope objective, thereby obtaining the micromorphology of the first surface. The only difference between this method and the previous method is the placement of the screen sample. The previous method simply lays the screen sample flat, while this method places the screen sample at an angle.

[0105] Specifically, Figure 7This is a schematic diagram showing the Fresnel lens unit array of the projection screen sample facing the objective lens. The normal F of the microstructure at each sampling point on the rough reflective interface was measured using a 3D laser microscope (KEYENCE VK-X1050). At 100x magnification, the Fresnel lens unit array of the projection screen sample is facing the objective lens (taking a circular arc Fresnel lens array as an example). Figure 7 As shown, the sample is placed horizontally with the Fresnel lens unit 1011 array arrangement direction as the horizontal direction. The x-direction represents the direction parallel to the first surface of the Fresnel lens unit, the y-direction represents the direction of the tangent of the Fresnel lens ring, and the z-direction represents the direction perpendicular to the first surface of the Fresnel lens unit. Figure 10 This is a schematic diagram of each sampling point. The sampling points are spaced L apart in the x-direction and K apart in the y-direction. The measurement area Q (refer to...) Figure 7 As shown) set in the Fresnel lens ring (e.g. Figure 7 As shown, in this example, the Fresnel lens array is arc-shaped, with a radial length of 145.337 μm (corresponding to 2048 sampling points) and a width of 108.985 μm (corresponding to 1536 sampling points) in the annular tangential direction. A microscopic image of the measurement region Q was obtained. Figure 7 A schematic diagram of the topography of region Q in the middle region, i.e. Figure 8 Because each Fresnel lens unit on the projection screen is designed with different tilt angles and cross-sectional shapes (such as the arc-shaped and straight-shaped cross-sections mentioned above), in order to eliminate the influence of different tilt angles or cross-sectional shapes of the Fresnel lens units on the test results, it is necessary to perform reference plane tilt correction on the microscopic image of the first surface of the Fresnel lens unit in the measurement area Q. (After selecting the reference plane setting in the Keyence analysis software, the software can directly obtain the tilt-corrected reference plane and the recalculated microscopic morphology data of each sampling point corresponding to the reference plane, thus obtaining...) Figure 7 A schematic diagram of the morphology of the mid-region after Q correction, i.e. Figure 9 When the microscope's analysis software lacks a reference plane setting function, the least squares method must be used for tilt correction calculations. The tooth bases of the annular teeth (areas with severe measurement distortion) are then trimmed to obtain the dataset M1 of measurement sampling points for the first surface of a single Fresnel lens unit within the measurement area Q. This dataset M1 truly reflects the microscopic morphology of the rough reflective interface on the first surface. Within the dataset M1, any point P is selected, and its position coordinates are recorded as (x0, y0), with a height value of z0. The position data of the eight points surrounding this point are extracted to form the neighborhood matrix D.

[0106]

[0107] dx = dy = 0.071um (the sampling point interval is known). For sampling points located on the boundary, the eight points closest to the sampling point are selected from the eight points of the neighborhood matrix.

[0108] Calculate the mean: Dx = x0; Dy = y0;

[0109] Calculate the difference matrix between the sampled data and the mean:

[0110]

[0111] Calculate the divergence matrix W:

[0112] W=UU T = (8-1)Cov(x,y,z);

[0113] The divergence matrix is ​​equal to the covariance matrix multiplied by (total data amount - 1), and both have the same eigenvalues ​​and eigenvectors. The eigenvector corresponding to the smallest eigenvalue of the covariance matrix is ​​the normal direction F of the micromorphology of that sampling point.

[0114] The formula for the covariance matrix is:

[0115]

[0116] Find the eigenvalues ​​and eigenvectors of the divination matrix W:

[0117] Transform the scatter matrix W into a diagonal matrix ∑, i.e., W = E∑E -1 .

[0118]

[0119] Wi = min(w1, w2, w3);

[0120] The normal direction of the microscopic morphology of the sampling point at coordinates (x0, y0) is n0 = (xi, yi, zi);

[0121] The elements on the diagonal of the matrix ∑ are the eigenvalues, and each column of the E matrix represents the eigenvector corresponding to the non-zero eigenvalue in the corresponding column of the ∑ diagonal. The final calculated normal direction F (e.g.) Figure 11 The schematic diagram of the normal direction F of the micro-morphology of each sampling point on the rough reflective interface that controls the direction of projection ray transmission and the normal direction Z of the reference plane is only related to the relative height of each sampling point in the field and the interval between each sampling point.

[0122] Figure 12This diagram illustrates the statistical direction of the normals F to the micro-morphology of each sampling point on the rough reflective interface controlling the direction of projected light transmission. The directions of the normals F to the micro-morphology of the first surface sampling points of a Fresnel lens unit in region Q are statistically determined. These normals F vary depending on the different rough reflective interface morphologies controlling the direction of projected light transmission on the first surface of the Fresnel lens unit. After correcting for the height data of the rough reflective interface controlling the direction of projected light transmission on the first surface of the Fresnel lens unit using a reference plane tilt correction, the direction of the normal Z to the reference plane is consistent at any position on the rough reflective interface of the first surface of the same Fresnel lens unit, being parallel to the z-axis in the coordinate system. However, there are multiple angles α between the normals F to the micro-morphology of each sampling point and the normal Z to the reference plane of the rough reflective interface controlling the direction of projected light transmission on the first surface. Figure 13 This diagram illustrates the included angle α, which is related to the direction of the normal F of the micro-morphology at each sampling point. In other words, it is directly related to the micro-morphology of the rough reflective interface on the first surface of the Fresnel lens unit, which controls the direction of projection light transmission. Different micro-morphologies of the rough reflective interface determine different directions of the normal F, thus forming different included angles α. When the included angle α is greater than a certain value, the projection light incident on the projection screen, after passing through the Fresnel lens unit, is more likely to undergo total reflection at the interface of the projection screen's internal structure (according to optical principles, the larger the incident angle of the incident light, the easier it is for total reflection to occur at the interface). Therefore, it is necessary to obtain the value of the included angle α of the projection screen that satisfies the requirements of this invention, thereby determining the direction of the normal F of the micro-morphology at each sampling point that satisfies the requirements of this invention, and further determining the morphology data of the rough reflective interface on the first surface of the Fresnel lens unit.

[0123] The angle α between the normal F of the micro-morphology of the sampling point on the rough reflective interface and the normal Z of the reference plane of the rough reflective interface.

[0124] According to an embodiment of the projection screen of the present invention, such as Figure 13As shown, the side furthest from the Fresnel lens unit is assumed to be smooth. Projected light ray G enters from the projection screen plane at an angle of 13°. It enters the Fresnel lens layer (material refractive index 1) from air (refractive index 1) and undergoes at least one refraction. According to the law of refraction, 1*sinθ1=1.562*sinγ, θ1=90°-13°=77°. The calculated angle γ between the refracted projected light ray and the projection screen normal N is approximately 38.6 degrees. Assuming the light ray exits perpendicular to the screen plane in the same direction as the screen normal N, the tilt angle of the first surface of the Fresnel lens unit at this location is γ / 2=19.3°. When the projected light rays are incident on the rough reflective interface on the first surface of the Fresnel lens unit, which controls the direction of the projected light rays, the projected light rays will form outgoing light rays in various directions on the rough reflective interface. According to the total internal reflection condition and the tilt angle of the first surface of the Fresnel lens unit at this position, it can be calculated that after reflection by the rough reflective interface on the first surface of the Fresnel lens unit, which controls the direction of the projected light rays, the maximum angle β between the outgoing light rays that will not be totally reflected at the internal structural interface of the screen and the screen normal N is 39.8°. That is, only the portion of the outgoing projected light rays that are reflected in various directions by the rough reflective interface, with an angle β less than 39.8° with the screen normal N, can successfully exit from inside the screen to the viewer area, while the portion of the projected light rays with an angle greater than or equal to 39.8° will be mostly consumed and lost due to total internal reflection at point O or other positions inside the screen. According to the law of reflection in optics, when the incident angle of the projected light on the first surface of the Fresnel lens unit is θ, the angle α between the normal F of the micro-morphology at each sampling point on the rough reflective interface that controls the transmission direction of the projected light and the normal Z of the reference plane of the rough reflective interface is α = (β + γ) / 2 - γ / 2 = β / 2. At this time, the direction of the projected light emitted after reflection through the rough reflective interface depends only on the normal F of the micro-morphology at each sampling point on the rough reflective interface that controls the transmission direction of the projected light, that is, only on the morphology of the rough reflective interface. To minimize total internal reflection at each interface layer, the rough reflective interface should ensure that the angle α between the normal F of each micro-morphology and the normal Z of the reference plane of the rough reflective interface is less than β / 2.When the angle β between the projected ray reflected by the rough reflective interface and the normal N of the projection screen is 39.8 degrees, the angle α between the normal F of the micro-morphology of the point on the rough reflective interface and the normal Z of the reference plane of the rough reflective interface on the first surface of the Fresnel lens unit is 19.9 degrees. (This angle is only related to the material of the Fresnel lens layer. Generally, the refractive index of the Fresnel lens layer material does not vary much and is greater than the refractive index of air. Therefore, no matter what the refractive index of the Fresnel lens layer material is, the total internal reflection condition can be met, and the calculated angle α is also not much different, which also meets the requirements of this invention.) Furthermore, as analyzed above, the normal F of the micro-morphology at each sampling point on the rough reflective interface of the first surface of the Fresnel lens unit determines the morphological characteristics of the rough reflective interface. Therefore, controlling the morphology of the rough reflective interface can control the angle α between the normal F of each micro-morphology and the normal Z of the reference plane of the rough reflective interface on the first surface of the Fresnel lens unit. This, in turn, controls the number of total internal reflections of the projected light at the rough reflective interface on the first surface of the Fresnel lens unit, which has a very good effect on improving the light energy utilization and display brightness of the projection screen. In addition, controlling the morphology of the rough reflective interface can also control the distribution range of the projected light emitted after passing through the rough reflective interface, which can also effectively improve the light energy utilization and display brightness.

[0125] Within a certain range, the normal F of the micromorphology at each sampling point of the rough reflective interface is statistically analyzed using probability statistics.

[0126] Figure 14 This is a frequency statistical histogram of the angle between normal F and normal Z on the projection screen of the present invention; Figure 15 This is a cumulative probability distribution diagram of the angle between the normal F and the normal Z on the projection screen of the present invention.

[0127] Based on the method for calculating the normal F of the micro-morphology at each sampling point on the rough reflective interface described above, the included angle α data in the dataset M1 of the measured sampling points within the sampling area on the rough reflective interface after tilt correction are statistically analyzed. The frequency of the normal F of the micro-morphology at that angle is plotted with the horizontal axis representing the angle and the vertical axis representing the frequency of the normal F of the micro-morphology at that angle. Figure 14 The frequency histogram of the normal F of the microscopic morphology of the sampling points with included angles in the interval [0°, 90°].

[0128] Furthermore, based on the discrete data of the frequency histogram of the normal F of the micro-morphology of the sampling points, it is normalized, with the horizontal axis representing angle and the vertical axis representing the cumulative probability at the corresponding angle, as shown in the figure. Figure 15 The cumulative probability distribution diagram shown is from... Figure 14 It can be seen that the included angle α occurs most frequently around 8°, and no included angles greater than 60° appear. From Figure 15It can be seen that the cumulative frequency of the normal F of the micromorphology of the sampling points with an included angle α of less than 60° is as high as 100%, and the cumulative frequency of the normal F of the micromorphology of the sampling points with an included angle α in the range of [0°, 19.9°] reaches about 92%. That is, only about 8% of the projected light will be lost due to total internal reflection inside the screen. The utilization rate of light energy of this projection screen is extremely high.

[0129] Further explanation, Figure 16 and Figure 17 The figures show the frequency histogram and cumulative probability distribution of a rough reflective interface, where the frequency of the normal F of the micromorphology of the sampling points within the range of [0°, 19.9°] accounts for 99% of the total frequency. The luminance coefficient of the orthographic projection screen containing this rough reflective interface (with the viewer and projector located on the same side of the screen) tested according to the definitions and test methods of Chinese National Standard GB / T 32200-2015 and industry standard JB / T 13294-2017 is 1.5–2.5 (luminance coefficient is an indicator reflecting the brightness of the projection screen; the higher the luminance coefficient, the higher the screen's brightness. The standard requires a value greater than 0.8. Samples with different rough surfaces on various screens were tested; due to the different scattering effects of the rough surfaces on the screen, the measured luminance coefficient values ​​have a certain range). Figure 18 and Figure 19 The images show the frequency histogram and cumulative probability distribution of a rough reflective interface with a sampling point microstructure normal F in the range of [0°, 19.9°], representing one embodiment. The brightness coefficient, tested according to the definitions and test methods of Chinese National Standard GB / T 32200-2015 and industry standard JB / T 13294-2017, ranges from 1.2 to 1.3 (samples with different surface textures on various screens were tested; due to the different scattering effects of the surface textures on the screen, the measured brightness coefficient values ​​have a certain range). Figure 20 and Figure 21 The images show the frequency histogram and cumulative probability distribution of a rough reflective interface with a sampling point micromorphology normal F in the range of [0°, 19.9°], representing one embodiment. The luminance coefficient, tested according to the definitions and test methods of Chinese National Standard GB / T 32200-2015 and industry standard JB / T 13294-2017, ranges from 0.8 to 1.0 (samples with different surface textures on various screens were tested; due to the different scattering effects of the surface textures on the screen, the measured luminance coefficient values ​​have a certain range). Figure 22 and Figure 23The figures show the frequency histogram and cumulative probability distribution of a rough reflective interface with a sampling point microstructure normal F in the range of [0°, 19.9°], representing one embodiment. The luminance coefficient, tested according to the definitions and test methods of Chinese National Standard GB / T 32200-2015 and industry standard JB / T 13294-2017, ranges from 0.4 to 0.6 (samples with different surface textures on various screens were tested; due to the different scattering effects of the surface textures on the screen, the measured luminance coefficient values ​​have a certain range). From the brightness coefficient values ​​tested in the aforementioned four embodiments, it can be concluded that when the cumulative frequency percentage of normal F within the range of [0°, 19.9°] of the angle α between normal F and normal Z is 70%, the brightness coefficient value of the projection screen of the present invention meets the minimum requirement of the standard; when the cumulative frequency percentage of normal F within the range of [0°, 90°] of the angle α between normal F and normal Z is 99%, the brightness coefficient value is much greater than the standard requirement value; when the cumulative frequency percentage of normal F within the range of [0°, 19.9°] of the angle α between normal F and normal Z is 52% (which can also be equivalent to the proportion of projection light rays that are fully emitted inside the screen being as high as 48%, resulting in a large amount of projection light being lost), The brightness coefficient value is less than the standard requirement, failing to meet the requirements. Therefore, it can be known that the brightness coefficient value of the screen is directly related to the cumulative frequency ratio of the normal F in the range of [0°, 19.9°], which is directly related to the morphology of the rough reflective interface. Therefore, this invention preferably uses the height data of each sampling point obtained by sampling the rough reflective interface controlling the transmission direction of the projected light on the projection screen in the thickness direction. After correcting the reference plane tilt, the normal Z of the reference plane of the rough reflective interface and the normal F of the micromorphology of each sampling point are calculated. The cumulative frequency ratio of the normal F in the range of 0° to 19.9° is 70% or more. Thus, it can be concluded that the brightness and light energy utilization of the projection screen containing the rough reflective interface of this invention are greatly improved, that is, the light energy loss of the screen is minimal.

[0130] like Figure 26 The diagram illustrates an image display system according to an embodiment of the present invention. The projection system 20 includes a projection screen 10 and a projector Y that projects projection light onto the projection screen. The projection light G emitted by the projector Y passes through the Fresnel lens layer 101, the first surface 1012 of the Fresnel lens unit 1011, and the rough reflective interface on the projection screen 10 before exiting into the viewing area. The projection system of the present invention, by precisely controlling the transmission direction of the projection light emitted through the Fresnel lens unit, greatly reduces the number of projection lights undergoing total internal reflection within the projection screen structural layer and the number of reflections. This reduces the amount of projection light absorbed by the screen structural layer after multiple reflections, thereby improving the brightness and light energy utilization of the projection system and reducing light energy loss.

[0131] Figure 27 This is a schematic diagram of a conical roller according to an embodiment of the present invention. A microstructure 1041, complementary to the aforementioned Fresnel lens unit 1011, is provided on the roller surface of the conical roller 104. The first surface of the microstructure 1041 is a rough surface 105, and the average roughness of the rough surface 105 is 0.1 μm or more, preferably 0.16 μm or more, more preferably 0.23 μm or more, further preferably 0.28 μm or more, and further more preferably 0.36 μm or more. Furthermore, the average roughness of the rough surface 105 of the microstructure, obtained from the cross-sectional morphology curve of the first surface measured from any microstructure on the conical roller, should be 1 μm or less, preferably 0.8 μm or less, more preferably 0.6 μm or less, and even more preferably... The vertical height between the top of the protrusion and the bottom of the adjacent depression of the rough surface 105 of the microstructure obtained by measuring the cross-sectional morphology curve of the first surface obtained by measuring any microstructure 1041 on the conical roller is 0.05 μm or more, preferably 0.1 μm, more preferably 0.3 μm, further preferably 0.5 μm, and even more preferably 1 μm; in addition, the vertical height between the top of the protrusion and the bottom of the adjacent depression of the rough surface 105 obtained by measuring the cross-sectional morphology curve of the rough surface 105 obtained by measuring any microstructure on the conical roller is 10 μm or less, preferably 8 μm, more preferably 6 μm, further preferably 5 μm, and even more preferably 3 μm.

[0132] Furthermore, the height data of each sampling point obtained by the conical roller sampling the rough surface 105 radially is corrected for reference plane tilt. The cumulative frequency percentage (%) of the angle between the normal of the micro-morphology of the sampling point of the rough surface and the normal of the reference plane of the rough surface is within 0° to 19.9° is 70% or more. Wherein, the cumulative frequency percentage (%) of the angle between the normal of the micro-morphology of the sampling point of the rough surface and the normal of the reference plane of the rough surface is within 0° to 19.9° is the percentage of the number of micro-morphology normals of the sampling point within the angle of 0° to 19.9° to the total number of micro-morphology normals of all sampling points.

[0133] Preferably, from the small end to the large end of the conical roller, the average roughness of the rough surface 105 of the microstructure 1041 gradually decreases. One embodiment is as follows: from the small end apex of the conical roller along the generatrix of the conical surface towards the large end, the average roughness within the range of a generatrix length less than or equal to 650 mm decreases from 0.294 μm to 0.188 μm; the average roughness within the range of a generatrix length greater than 650 mm and less than or equal to 1144 mm decreases from 0.199 μm to 0.171 μm; and the average roughness within the range of a generatrix length greater than 1144 mm decreases from 0.187 μm to 0.169 μm.

[0134] Further explanation: the average roughness of the rough surface 105 of the conical roller, the vertical height between the top of the protrusion and the bottom of the adjacent depression of the rough surface 105, the normal of the micro-morphology of each sampling point on the rough surface 105, the angle between the normal of the micro-morphology of each sampling point on the rough surface 105 and the normal of the reference plane of the rough surface 105, and the calculation method of the cumulative frequency ratio of the normal in the range of 0° to 19.9°, the microscopic image testing method, and the specific instrument parameter settings for testing the microscopic image are all the same as those described above, and will not be repeated here. It should be added that when a small-sized conical roller that meets the requirements is manufactured, the microscopic image of the rough surface 105 of the microstructure 1041 on the conical roller can be directly tested using a laser microscope; however, when the conical roller is large and cannot be placed in a laser microscope for testing, the microstructure 1041 on the surface of the conical roller can be replicated using silicone, and then the microscopic image on the silicone can be tested to obtain the morphological characteristics of the rough surface 105 on the conical roller.

[0135] Further explanation: A Fresnel lens layer can be formed on a substrate using a coating transfer method. This method involves pressing a resin composition containing a radiation-curable resin as the main component onto the substrate using a tapered roller, and then irradiating the resin composition with ultraviolet light to harden it, thereby transferring the microstructure on the tapered roller surface to the substrate surface. Alternatively, a hot-pressing method can be used to form the Fresnel lens layer. This method involves pressing a heated substrate surface with a tapered roller and then cooling it, thereby transferring the microstructure on the tapered roller surface to the substrate surface. In terms of production quality, the coating transfer method is preferred.

[0136] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A projection screen, characterized in that, A Fresnel lens layer for controlling the direction of projection light transmission is provided on the projection screen. The Fresnel lens layer includes a plurality of Fresnel lens units with a sawtooth cross-section arranged in the same direction on the plane of the projection screen. Each Fresnel lens unit includes a first surface for controlling the direction of projection light transmission. A reflective material is provided on the first surface. The reflective material and the first surface form a rough reflective interface. The rough reflective interface is used to precisely control the direction of projection light transmission. The average roughness of the rough reflective interface is greater than 0.1 μm and less than 1 μm; The rough reflective interface is sampled in the thickness direction of the screen, and the height data of each sampling point is corrected for reference plane tilt. The normal of the reference plane of the rough reflective interface is Z, the normal of the micro-morphology of the sampling point on the rough reflective interface is F, and the angle between the normal of the micro-morphology of the sampling point on the rough reflective interface and the normal of the reference plane of the rough reflective interface is α. The cumulative frequency of the angle α in the range of 0° to 19.9° is 70% or more. Wherein: the cumulative frequency proportion of the included angle α within 0° to 19.9° is the percentage of the number of micromorphic normals of the sampling points within the included angle α within 0° to 19.9° to the total number of normals of the micromorphic features of all sampling points; The vertical height between the top of the protrusion and the bottom of the adjacent depression on the rough reflective interface is greater than 0.05 μm and less than 10 μm.

2. The projection screen according to claim 1, characterized in that, The Fresnel lens units are arranged in a circular arc array, a parabolic array, an elliptical arc array, or a linear array.

3. The projection screen according to claim 2, characterized in that, The reflective material has a thickness of 80 nm or more and an average reflectivity of 50% or more for visible light.

4. The projection screen according to claim 2, characterized in that, The reflective material is made using a vacuum coating method.

5. An image display system, characterized in that, Includes the projection screen as described in any one of claims 1 to 4 and the projector that projects projection light onto the projection screen.

6. The image display system according to claim 5, characterized in that, The average roughness of the rough reflective interface gradually decreases from the edge closest to the projector toward the edge furthest from the projector.

7. A conical roller, characterized in that, A microstructure complementary to the Fresnel lens unit as described in claim 1 is provided on the surface of the tapered roller, wherein the first surface of the microstructure is a rough surface; The average roughness of the rough surface is greater than 0.1 μm and less than 1 μm; The rough surface is sampled radially by the conical roller, and the height data of each sampling point is corrected for reference plane tilt. The cumulative frequency of the angle between the normal of the micromorphology of the sampling point of the rough surface and the normal of the reference plane of the rough surface is within 0° to 19.9° is 70% or more. Wherein: the cumulative percentage of the frequency of the angle between the normal of the micromorphology of the sampling point of the rough surface and the normal of the reference plane of the rough surface is within 0° to 19.9° is the percentage of the number of normals of the micromorphology of the sampling point within the angle of 0° to 19.9° to the total number of normals of the micromorphology of all sampling points. The vertical height between the top of the protrusion and the bottom of the adjacent depression on the rough surface is greater than 0.05 μm and less than 10 μm.

8. The conical roller according to claim 7, characterized in that, From the small end to the large end of the conical roller, the average roughness of the rough surface gradually decreases.

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