Projection screen and projection system

Abstract

Disclosed in the present application are a projection screen and a projection system. The projection screen comprises a Fresnel lens layer, a reflective structure layer located on the surfaces of lens units of the Fresnel lens layer, and a first diffusion layer located on the side of the Fresnel lens layer facing away from the reflective structure layer. After being incident on the projection screen, projection light rays first pass through the first diffusion layer, the projection light rays are then subjected to first diffusion to a small extent by means of the first diffusion layer, and the incident angle at which the projection light rays are incident on the reflective structure layer satisfies an original design value, such that the projection light rays can be efficiently reflected by the reflective structure layer; and the reflected projection light rays are incident on the first diffusion layer again, and then are emitted out after being subjected to second diffusion to a great extent by means of the first diffusion layer, thus increasing the diffusion angle of the projection light rays. The first diffusion layer can better exert the function of the reflective structure layer, thus enabling projection screens to achieve higher contrast.

Description

Projection screen and projection system

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202410833190.9, filed on June 26, 2024, and entitled "A projection screen and projection system", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the field of projection technology, in particular to a projection screen and a projection system. BACKGROUND

[0004] With the development of display products towards large size, considering the power consumption, weight and size, etc., the market of projection display products as a large screen display product to replace Liquid Crystal Display (LCD) and Organic Light-Emitting Diode (OLED) televisions is rapidly expanding. Laser televisions using ultra-short focus projection equipment have rapidly developed due to their high image quality and convenience of large screen.

[0005] The current projection system can usually be used with a projection screen. In order to improve the contrast of the projected image, a functional layer for selectively emitting the projected light can be provided in the projection screen. The functional layer is sensitive to the incident angle. If the incident angle of the light incident on the functional layer deviates from the design value to a large extent, the efficiency of the functional layer will be reduced. However, in order to expand the viewing range of the screen, a film layer for diffusing light is often provided in the screen. The above functional layer is difficult to achieve the theoretical maximum value in principle. SUMMARY

[0006] The present application provides a projection screen, comprising:

[0007] a Fresnel lens layer; the Fresnel lens layer comprises a plurality of lens units, the lens units comprise a lens surface and a non-lens surface; the lens surface is arranged obliquely relative to the plane in which the projection screen is located;

[0008] a reflective structure layer covering at least the lens surface of each lens unit; the reflectivity of the reflective structure layer to the projection light emitted by the projection device is greater than the reflectivity to light of other wavelengths;

[0009] a first diffusion layer located on the side of the Fresnel lens layer away from the reflective structure layer;

[0010] The projection light emitted by the projection device is incident on the projection screen, first incident on the first diffusion layer, secondarily incident on the Fresnel lens layer after first diffusion by the first diffusion layer, reflected by the wave reflection structure layer on the surface of each lens unit of the Fresnel lens layer, and thirdly incident on the first diffusion layer, emitted after second diffusion by the first diffusion layer.

[0011] The embodiment of the present application further provides a projection system, comprising:

[0012] a projection device configured to emit projection light; and

[0013] a projection screen located on the light emitting side of the projection device, wherein the projection screen is the projection screen described above. BRIEF DESCRIPTION OF DRAWINGS

[0014] Fig. 1 is a structural schematic diagram of a projection system provided by the embodiment of the present application;

[0015] Fig. 2 is a schematic diagram of a cross-sectional structure of a projection screen provided by the embodiment of the present application;

[0016] Fig. 3 is a schematic diagram of a planar structure of a Fresnel lens layer provided by the embodiment of the present application;

[0017] Fig. 4 is a schematic diagram of a cross-sectional structure of a projection screen provided by the embodiment of the present application;

[0018] Fig. 5 is a schematic diagram of a cross-sectional structure of a reflection structure layer provided by the embodiment of the present application;

[0019] Fig. 6 is a schematic diagram of light diffusion provided by the embodiment of the present application;

[0020] Fig. 7 is a schematic diagram of a cross-sectional structure of a projection screen provided by the embodiment of the present application;

[0021] Fig. 8 is a schematic diagram of a reflectivity curve of a projection screen provided by the embodiment of the present application;

[0022] Fig. 9 is a schematic diagram of a reflectivity curve of a projection screen provided by the embodiment of the present application;

[0023] Fig. 10 is a schematic diagram of a planar structure of a first diffusion layer provided by the embodiment of the present application;

[0024] Fig. 11 is a schematic diagram of a cross-sectional structure of a first diffusion layer provided by the embodiment of the present application;

[0025] Fig. 12 is a schematic diagram of a cross-sectional structure of a first diffusion layer provided by the embodiment of the present application;

[0026] FIG. 13 is a second plan view of a first diffusion layer according to an embodiment of the present application;

[0027] FIG. 14 is a fourth cross-sectional view of a projection screen according to an embodiment of the present application;

[0028] FIG. 15 is a fifth cross-sectional view of a projection screen according to an embodiment of the present application;

[0029] FIG. 16 is a sixth cross-sectional view of a projection screen according to an embodiment of the present application;

[0030] FIG. 17 is a seventh cross-sectional view of a projection screen according to an embodiment of the present application;

[0031] FIG. 18 is a structural view of a projection device according to an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the above objectives, features and advantages of the present application more apparent, further description will be given below with reference to the accompanying drawings and embodiments. However, the example embodiments can be implemented in various forms, and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided in order to make the present application more comprehensive and complete, and to fully convey the ideas of the example embodiments to those skilled in the art. Identical reference numerals in the drawings represent identical or similar structures, and thus repeated description thereof will be omitted. The expressions of position and direction described in the present application are described with reference to the drawings, but can be changed as needed, and the changes made are included in the scope of protection of the present application. The drawings of the present application are only used to illustrate the relative positional relationship and do not represent the true proportions.

[0033] With the popularization of laser display products, as large-screen products to replace LCD TVs and OLED TVs, the market for laser TVs has rapidly expanded. In order to achieve better brightness and display effect, projection devices are generally used with projection screens.

[0034] As shown in FIG. 1, the projection system includes a projection device 2 and a projection screen 1.

[0035] The projection screen 1 is located on the light exit side of the projection device 2, and the audience faces the projection screen 1. The projection device 2 emits projection light, the projection light is incident on the projection screen 1, and the projection light is emitted in the direction of the audience after passing through the projection screen 1, so that the audience can watch the projected image.

[0036] The projection system is referred to as a front projection system when the projection device 2 and the audience are located on the same side of the projection screen 1, and is referred to as a rear projection system when the projection device 2 and the audience are located on two sides of the projection screen 1 respectively. In the front projection system, the projection device 2 emits projection light to the projection screen 1, and the projection screen 1 reflects the projection light to the audience, so that the audience can view the projection image. In the rear projection system, the projection device 2 emits projection light to the projection screen 1, and the projection light is emitted to the audience through the projection screen 1, so that the audience can view the projection image.

[0037] The projection screen 1 can be installed on a wall or hung at a high place, or can be integrated with the projection device to form a display device. In the use state, the projection device 2 can be located below the projection screen 1, and emits projection light to the projection screen 1 from the lower side to the obliquely upper side of the projection screen 1; or the projection device 2 can be located above the projection screen 1, and emits projection light to the projection screen 1 from the upper side to the obliquely lower side of the projection screen 1. Since the ultra-short focus projection system has a small projection ratio, a large-size projection image can be obtained while reducing the distance between the projection device 2 and the projection screen 1, and is very suitable for application in scenes such as laser television.

[0038] As shown in FIG. 1, the projection screen 1 is usually rectangular in shape, and in use, the side edges of the bottom and the side edges of the top are usually parallel to the horizontal direction x, and the side edges of the two sides are parallel to the vertical direction y. The horizontal direction x refers to a direction parallel to the horizontal plane, and the vertical direction y refers to a direction in the plane of the projection screen and perpendicular to the horizontal direction. The projection device 2 is taken as an example to be arranged close to the side edge of the bottom of the projection screen 1.

[0039] FIG. 2 is a projection screen used in cooperation with a front projection system. As shown in FIG. 2, the projection screen includes a surface functional layer 11, a Fresnel lens layer 12 and a reflection layer 13.

[0040] The surface functional layer 11 can be located at the outermost surface of the projection screen. In some embodiments, the surface functional layer 11 is located on the side closest to the audience, and plays a role of protecting the projection screen. In addition, the surface functional layer 11 can be processed in various ways according to different needs, so as to achieve the effects of expanding the viewing angle, resisting environmental light reflection, resisting ceiling light reflection, etc.

[0041] As shown in FIG. 2 and FIG. 3, the Fresnel lens layer 12 is located on the side of the surface functional layer 11 away from the audience. A plurality of lens units 121 arranged according to a set rule are included in the Fresnel lens layer 12. As shown in FIG. 3, the plurality of lens units 121 can constitute concentric circles arranged in a radial direction in turn. When the projection screen is applied to an ultra-short focus projection system, the center O of the concentric circular lens units 121 is usually not located in the projection screen, and when the projection device emits projection light from the projection screen in a downward direction, the center O of each lens unit 121 is located below the side of the bottom of the projection screen and on the extension line of the symmetry axis I-I' of the projection screen. In the direction from the bottom to the top of the projection screen, the radius of the lens unit 121 gradually increases, and the projection screen does not contain a complete circular lens, but only contains a partial circular arc-shaped lens.

[0042] As shown in FIG. 2, each lens unit 121 includes a lens surface x1 and a non-lens surface x2 connected to each other. Among them, the lens surface x1 is arranged obliquely with respect to the plane where the projection screen is located, and the oblique angle of the lens surface x1 is set according to the incident angle of the projection light, so that the emitted light of the projection device can be reflected in the direction of the audience when it is incident on the reflection layer 13 on the surface of the lens surface x1. The non-lens surface x2 is used to connect the lens surface x1, and the non-lens surface x2 can be a plane or a curved surface.

[0043] The arrangement of the Fresnel lens layer 12 in the projection screen is conducive to reflecting the projection light to the front of the projection screen, thereby improving the gain of the projection screen.

[0044] The reflection layer 13 at least covers the lens surface x1 of each lens unit 121 of the Fresnel lens layer 12. Since the oblique angle of the lens surface x1 of each lens unit 121 is designed to reflect the incident projection light in the direction of the audience, and the reflection layer 13 covers the lens surface x1 of the lens unit 121 and has the same oblique angle as the lens surface x1, the incident projection light can be reflected in the direction of the audience according to the original design.

[0045] The surface functional layer 11 of the projection screen usually has the function of light diffusion, which can expand the divergence angle of the light emitted by the projection screen, thereby increasing the viewing angle of the screen. However, the projection screen is easily affected by external light when viewed in strong light, and is not suitable for viewing images such as movies that often use dark scenes, resulting in a decrease in image contrast.

[0046] Therefore, the embodiment of the present application provides a projection screen, as shown in Fig. 4, which comprises a surface functional layer 11, a Fresnel lens layer 12 and a reflective structure layer F located on the surface of each lens unit 121 of the Fresnel lens layer 12. The reflective structure layer F can selectively enhance the reflection of the projection light emitted by the projection device by using the principle of resonance enhancement of light of a set wavelength, and absorb light of other wavelengths, so that the reflectivity of the reflective structure layer F to the projection light emitted by the projection device is greater than the reflectivity to light of other wavelengths, thereby realizing the black appearance when the projection device is turned off and obtaining the bright display when the projection device is turned on, so that the contrast of the projection image can be significantly improved.

[0047] As shown in Fig. 5, the reflective structure layer F can comprise a semi-transparent light layer 131, a reflective layer 132 and a transparent medium layer 133. The semi-transparent light layer 131, the transparent medium layer 133 and the reflective layer 132 are sequentially formed on the lens surface of each lens unit of the Fresnel lens layer. The semi-transparent light layer 131, the transparent medium layer 133 and the reflective layer 132 constitute a resonance structure.

[0048] The semi-transparent light layer 131 has the property of semi-transmission and semi-reflection, and it should be noted that the semi-transmission and semi-reflection property mentioned in the embodiment of the present application is not that the transmittance and reflectance of light are both 50%, but to show that the semi-transparent light layer 131 can realize the property of partially transmitting and partially reflecting light, and the transmittance and reflectance can be adjusted according to actual requirements, and the specific transmittance and reflectance of the semi-transparent light layer 131 are not limited herein. The semi-transparent light layer 131 can make the projection light incident into the resonance structure when the projection light is incident on the projection screen, and the projection light can also be emitted out of the semi-transparent light layer 131 after oscillating and enhancing in the resonance structure. In the specific implementation, the semi-transparent light layer 131 can adopt a laminated structure formed by at least one metal or two or more metals selected from Al, Nb, Ag and Ti.

[0049] The reflective layer 132 has the function of reflecting light, and the reflective layer 132 is located on the side far away from the audience and does not need to transmit light, so it can be made of a material with reflective property and no light transmission property. In the specific implementation, the reflective layer 132 can be made of Al, aluminum alloy, Ag or silver alloy, and the thickness of the reflective layer 132 is greater than the thickness of the semi-transparent light layer 131.

[0050] The thickness of the light-transmitting dielectric layer 133 determines the cavity length of the resonant structure, and thus the product of the refractive index and the thickness of the light-transmitting dielectric layer 133 determines the wavelength of the light that can be reflected. Therefore, when designing the resonant structure, a dielectric material with a product of the refractive index and the thickness satisfying the condition of resonance of the projection light emitted by the projection device needs to be selected. In a specific implementation, the light-transmitting dielectric layer 133 can be made of a metal oxide, a nitride, or a transparent resin.

[0051] The semi-transparent layer 131, the light-transmitting dielectric layer 133, and the reflective layer 132 can all be made by using a sputtering or evaporation process. When the resonant structure is used, a dielectric material with a suitable refractive index is selected as the light-transmitting dielectric layer 133, and the light-transmitting dielectric layer 133 is set to a suitable thickness, so that the reflection of the projection light can be enhanced.

[0052] In the embodiment of the present application, the projection light source can use a three-color laser light source device that can emit red laser light, green laser light, and blue laser light. By adjusting the refractive index and the thickness of the light-transmitting dielectric layer, the resonant structure can simultaneously enhance the reflection of the red laser light, the green laser light, and the blue laser light, and attenuate the reflection of light of other wavelengths, thereby improving the contrast of the projected image.

[0053] As shown in FIG. 4, when the projection screen is applied to the ultra-short focus projection system, the projection device is usually located below the projection screen and emits the projection light in an obliquely upward direction to the projection screen. The incident angle of the projection light L to the surface of the projection screen is a, and the position between the projection device and the projection screen is relatively fixed, so the incident angle of the projection light emitted by the projection device to different positions of the projection screen is different. In actual application, the incident angle a is 60°-85°. The light incident to the projection screen will be refracted multiple times and finally incident to the reflection structure layer F. The tilt angle of the lens surface x1 of each lens unit 121 of the Fresnel lens layer 12 to the plane where the projection screen is located is designed according to the incident direction of the projection light and the final reflection of the incident light to the front of the projection screen. In general, the tilt angle of the lens surface x1 of each lens unit 121 is designed according to the incident angle θ=12°-17° of the projection light to the lens surface x1 of each lens unit 121. Since the reflection structure layer F covers the lens surface x1 of each lens unit 121, the designed value of the incident angle of the projection light to the reflection structure layer F is also 12°-17°. The reflection structure layer F can adjust the refractive index and thickness according to the incident angle θ=12°-17°, so that the reflection structure layer F has a high reflectivity to the incident projection light. It has been verified that when the projection light is incident to the reflection structure layer F at an angle deviating from the designed value within ±10°, it will not have a great impact on the wavelength selection characteristics of the reflection structure layer F. However, when the projection light is incident to the reflection structure layer F at an incident angle exceeding the designed range, the wavelength selection characteristics will be deviated, resulting in a significant decrease in efficiency.

[0054] As shown in FIG. 6, the surface functional layer 11 of the projection screen usually has a large haze, which has a diffusion effect on light incident in any direction at any angle. Therefore, after the projection light L is incident to the projection screen, it first passes through the surface functional layer 11 and then reaches the reflection structure layer F after being diffused. This makes the projection light incident to the reflection structure layer F contain many components deviating from the designed angle, which cannot be efficiently reflected, resulting in attenuation of the projection light.

[0055] On the other hand, after the ambient light C is incident to the projection screen, it will also be diffused by the surface functional layer 11, so that the ambient light will be incident to the reflection structure layer F at multiple angles. After multiple reflections, part of the light will finally be emitted from the front of the projection screen, resulting in a decrease in the contrast of the projection light.

[0056] To overcome the above problems, the embodiment of the present application provides a projection screen, as shown in FIG. 7, which comprises a first diffusion layer K, a Fresnel lens layer 12 and a reflection structure layer F. The reflection structure layer F covers at least the lens surface x1 of each lens unit 121 of the Fresnel lens layer 12, and the first diffusion layer K is located on the side of the Fresnel lens layer 12 away from the reflection structure layer F.

[0057] The first diffusion layer K has a diffusion degree for light rays incident at a set angle range that is greater than the diffusion degree for light rays incident at other angles. The first diffusion layer K has the characteristic of angle-selective diffusion for incident light rays, and only has a diffusion effect on light rays at a set range of incident angles, and the diffusion effect on light rays at other incident angles is greatly reduced.

[0058] In combination with the above characteristics of the first diffusion layer, after the projection light L is incident on the projection screen, it first passes through the first diffusion layer K, is reflected by the reflection structure layer F on the surface of each lens unit after the first diffusion by the first diffusion layer K, and is incident on the Fresnel lens layer 12 again. The reflected projection light is incident on the first diffusion layer K again, and is emitted after the second diffusion by the first diffusion layer. The diffusion degree of the first diffusion layer K for the first diffusion of the projection light is less than the diffusion degree of the first diffusion layer K for the second diffusion of the projection light.

[0059] This is because the first diffusion layer K has the characteristic of angle-selective diffusion for incident light rays, and when the projection light L is incident on the first diffusion layer for the first time, the incident angle does not meet the angle range selected by the first diffusion layer K, so the projection light is diffused to a small degree after passing through the first diffusion layer K, or even no diffusion occurs, and the light is not diffused, so the incident angle when the light is incident on the reflection structure layer F can meet the original design value, so that the light can be efficiently reflected by the reflection structure layer F. The reflected projection light is incident on the first diffusion layer K again, and at this time, the incident angle of the reflected projection light incident on the first diffusion layer K meets the angle range selected by the first diffusion layer K, so that the reflected projection light L is diffused to a large degree by the first diffusion layer K and is emitted, thereby increasing the diffusion angle of the projection light and achieving the purpose of expanding the viewing angle.

[0060] On the other hand, the ambient light C incident to the projection screen first enters the first diffusion layer K. The incident angle of the ambient light C incident to the projection screen has diversity, and thus most of the ambient light C does not satisfy the angle range selected by the first diffusion layer K, is diffused to a smaller extent by the first diffusion layer K, and then enters the reflection structure layer F. Since the reflection structure layer F is designed according to the incident angle of the projection light, the reflection efficiency of the ambient light C is not high, and thus the ambient light reflected by the reflection structure layer F to the front of the projection screen is small, and the ambient light C reflected to other directions is incident to the first diffusion layer K again and still does not satisfy the angle range selected by the first diffusion layer K, and thus is not diffused to a large extent when exiting from the projection screen, thereby improving the contrast of the projection light.

[0061] FIGS. 8 and 9 show the reflectivity curves before and after the projection screen is provided with the first diffusion layer. As can be seen from the comparison between FIGS. 8 and 9, the reflection efficiency of the reflection structure layer for the three-color laser light is lost before the first diffusion layer is provided, and the reflection structure layer can better play a role after the first diffusion layer is provided in the projection screen, so that the projection screen has a higher contrast.

[0062] In some embodiments, as shown in FIG. 7, the projection screen further includes a second diffusion layer 11'. The second diffusion layer 11' is located on the side of the first diffusion layer K away from the Fresnel lens layer 12, and is located on the most surface side of the projection screen. The second diffusion layer 11' has a diffusion effect on light incident at any angle, and does not have the angle-selective diffusion characteristic. In addition, the second diffusion layer 11' does not need to have a high haze, and its role is to diffuse the incident light to a low extent, so that more projection light can satisfy the condition of entering the projection screen.

[0063] The haze and the transmittance of the diffusion layer are generally negatively correlated. The greater the haze, the greater the diffusion of light, and the lower the transmittance of light. The smaller the haze, the smaller the diffusion of light, and the higher the transmittance of light. In the embodiments of the present application, the second diffusion layer 11' does not need to have a large haze, and the haze thereof can be set to 2% to 10%, so that the projection light can enter the projection screen more while having a high transmittance.

[0064] The angle-selective diffusion characteristic of the first diffusion layer K is due to the refractive index difference of the first diffusion layer. Specifically, FIG. 10 is a plan view of the first diffusion layer, and FIG. 11 is a cross-sectional view of the first diffusion layer taken along the direction of a-a' in FIG. 10. As shown in FIGS. 10 and 11, the first diffusion layer K is a light-transmitting medium layer 151 including a plurality of micro bodies 152, which are three-dimensional structures, in the light-transmitting medium layer 151. The length of the micro bodies 152 along the thickness direction of the light-transmitting medium layer is greater than the length of the micro bodies 152 along the direction parallel to the plane of the light-transmitting medium layer, and the refractive index of the micro bodies 152 is different from the refractive index of the light-transmitting medium layer 151.

[0065] The size of the micro bodies 152 is in the order of microns, and there is a refractive index difference between the micro bodies 152 and the surrounding light-transmitting medium layer 151. When light enters from one medium into another medium with a different refractive index, the propagation direction of the light changes. Due to the difference in refractive index between the micro bodies 152 and the surrounding medium (the light-transmitting medium layer 151), the optical path length and the phase difference of the light wave change when the light wave passes through the interface between different media, resulting in reflection and refraction of the light wave. This reflection and refraction at the interface cause scattering. The micro bodies 152 can be regarded as scattering centers, and each scattering center causes the light to deviate from its original path when the light passes through these areas, thereby producing scattered light.

[0066] The micro bodies 152 themselves have directionality, which makes the refractive index of the light-transmitting medium layer unchanged along the thickness direction, and there is a difference in refractive index in the plane of the light-transmitting medium layer 151. This anisotropic change in refractive index means that the optical properties are different in different directions. Therefore, the scattering characteristics of the incident light also change with the change in the incident angle of the light.

[0067] When the projection screen is used with the ultra-short focus projection system, it is desirable that the reflected light is finally reflected by the reflection structure layer F to the front of the projection screen. The tilt angle of the lens surface of each lens unit of the Fresnel lens layer is designed according to this effect. In this case, when the reflected projection light exits to the outside of the projection screen, the incident angle of the reflected projection light to the first diffusion layer K is very small, usually within the range of -10° to 10°, and the design center is that the reflected projection light is normally incident to the first diffusion layer K. Therefore, the range of the incident angle of the first diffusion layer K for selective diffusion can be designed to be -10° to 10°, and at this time, the micro bodies 152 distributed in the light-transmitting medium layer 151 can extend along the thickness direction of the light-transmitting medium layer 151, so that the light-transmitting medium layer 151 has no refractive index change along its thickness direction, and there is a difference in refractive index in its plane direction.

[0068] In some embodiments, as shown in FIGS. 10 and 11, the micro bodies 152 can be columnar body structures, and the axis direction of the columnar body structures is parallel to the thickness direction of the light-transmitting medium layer 151.

[0069] The light-transmissive medium layer 151 needs to be made of a suitable material, for example, a resin material with photopolymerizability can be used. Specifically, a resin containing a photopolymerizable compound is coated on a substrate to form a thin film, and the thin film is cured by light irradiation and / or heating. The photopolymerizable compound undergoes a polymerization reaction under light irradiation, resulting in a change in refractive index and formation of columnar structures (microstructures 152). By changing the direction of light irradiation or using specific light curing conditions, the orientation of the columnar structures can be changed.

[0070] In some embodiments, as shown in FIG. 12, the microstructures 152 described above can also be formed by dispersing particles in the light-transmissive medium layer 151, the particles having a different refractive index from that of the light-transmissive medium layer 151 and being ellipsoidal in shape, with the long axis parallel to the thickness direction of the light-transmissive medium layer 151, so that the length of the particles in the thickness direction of the light-transmissive medium layer is greater than the length in the direction parallel to the plane of the light-transmissive medium layer. In this way, the light-transmissive medium layer has no change in refractive index in the thickness direction, and a difference in refractive index in the plane direction.

[0071] The degree of diffusion of the first diffusion layer K for light rays incident at a set angle range can be achieved by adjusting the refractive index difference between the light-transmissive medium layer 151 and the microstructures 152, the number of periods of refractive index change, and the thickness of the light-transmissive medium layer 151.

[0072] In some embodiments, if the refractive index of the light-transmissive medium layer 151 is n1 and the refractive index of the microstructures 152 is n2, the degree of diffusion of the first diffusion layer K for incident light rays can be increased by increasing the difference between n1 and n2. This is because when light rays are incident from one medium to another, the greater the difference in refractive index between the two media, the greater the angle of deflection when the light rays are incident into the other medium. By adjusting the refractive index difference between the light-transmissive medium layer 151 and the microstructures 152, the desired diffusion angle can be achieved using the refractive properties of light rays.

[0073] In specific implementations, considering the selection of materials, the cost of production, and the ease of the process, the light-transmissive medium layer 151 and the microstructures 152 can both be made of an acrylic resin material, and the refractive index n1 of the light-transmissive medium layer 151 is 1.48-1.50. Furthermore, the refractive index n1 of the light-transmissive medium layer 151 and the refractive index n2 of the microstructures 152 differ by 0.02-0.05, i.e., n2 = n1 ± 0.02-0.05.

[0074] In some embodiments, the degree of diffusion of the first diffusion layer K for incident light rays can be increased by increasing the thickness of the first diffusion layer K. The greater the thickness of the first diffusion layer K, the more times the light rays are reflected and refracted in the two media, thereby exhibiting stronger diffusion.

[0075] In a specific implementation, the first diffusion layer K can be obtained by gravure printing or slit coat, etc. to obtain a suitable film thickness. As shown in FIG. 7, the thickness h of the first diffusion layer K can be 10 μm to 100 μm, and preferably about 50 μm.

[0076] In some embodiments, the degree of diffusion of the first diffusion layer K to the incident light can be increased by increasing the number of change cycles of n1 and n2.

[0077] Specifically, FIG. 10 and FIG. 13 are both plan views of the first diffusion layer, i.e. the state of the first diffusion layer when the projection screen is placed facing the audience in a use state, and the audience observes the projection screen. The first diffusion layer is in the shape of a rectangle as a whole, with the long side parallel to the horizontal direction x and the short side parallel to the vertical direction y. The horizontal direction x and the vertical direction y are perpendicular to each other.

[0078] In the first diffusion layer shown in FIG. 10, the micro bodies 152 are circular in cross section along the x-y plane, and the micro bodies 152 are uniformly distributed in the light-transmitting medium layer 151. The distance between adjacent micro bodies 152 is equal in both the horizontal direction x and the vertical direction y. If the refractive index of the medium changes from n1 to n2 is referred to as one cycle, then the more the number of cycles of the change in refractive index, the greater the frequency of the change in refractive index. Then, as shown in FIG. 10, the frequency of the change in refractive index of the light-transmitting medium layer 151 and the micro bodies 152 is the same in both the horizontal direction x and the vertical direction y, which makes the degree of diffusion of the light along the horizontal direction x and the degree of diffusion of the light along the vertical direction y after the light is diffused by the first diffusion layer K the same, and the light has the same diffusion angle in the horizontal direction and the vertical direction after passing through the first diffusion layer K.

[0079] In the first diffusion layer shown in FIG. 10, the micro bodies 152 are circular in cross section along the x-y plane, and the micro bodies 152 are uniformly distributed in the light-transmitting medium layer 151. The distance between adjacent micro bodies 152 is equal in both the horizontal direction x and the vertical direction y. If the refractive index of the medium changes from n1 to n2 is referred to as one cycle, then the more the number of cycles of the change in refractive index, the greater the frequency of the change in refractive index. Then, as shown in FIG. 10, the frequency of the change in refractive index of the light-transmitting medium layer 151 and the micro bodies 152 is the same in both the horizontal direction x and the vertical direction y, which makes the degree of diffusion of the light along the horizontal direction x and the degree of diffusion of the light along the vertical direction y after the light is diffused by the first diffusion layer K the same, and the light has the same diffusion angle in the horizontal direction and the vertical direction after passing through the first diffusion layer K.

[0080] In a specific implementation, the projection screen needs to have a larger viewing angle in the horizontal direction x, the micro bodies 152 in the first diffusion layer K can be adjusted to have a length in the horizontal direction x smaller than a length in the vertical direction y, so as to increase the diffusion angle of the light in the horizontal direction x, and the diffusion angle of the first diffusion layer K in the horizontal direction x reaches 15°-40°, and the diffusion angle in the vertical direction y reaches 5°-20°.

[0081] Referring to the manufacturing process of the common diffusion layer in the related art and the size of the diffusion particles, as shown in FIG. 10, in the x-y cross section parallel to the plane where the light-transmitting medium layer is located, the length w of the micro body 152 is 1 μm-10 μm, and is preferably about 3 μm-7 μm, and the pitch p of the adjacent micro bodies 152 is about 2 μm-5 μm.

[0082] As shown in FIG. 7, the Fresnel lens layer 12 can include a first substrate 122, and a plurality of lens units 121 are formed on the surface of the first substrate 122, so that the first substrate 122 can also simultaneously serve as the substrate of the first diffusion layer K, and the first diffusion layer K is formed on the side of the first substrate 122 opposite to the lens units 121. The second diffusion layer 11’ is formed on the surface of the first diffusion layer K, and the second diffusion layer 11’ can be formed on the surface of the first diffusion layer K by sandblasting or the like, so that the surface of the first diffusion layer K forms a concave-convex structure and has a lower diffusion property. The above projection screen structure is compact, and the thickness can be made thinner.

[0083] In a specific implementation, the first diffusion layer K with angle selectivity cooperates with the second diffusion layer 11’ with low diffusion, so that the diffusion angle of the projection screen in the horizontal direction x is 20°-45°, and the diffusion angle in the vertical direction y is 10°-25°.

[0084] In some embodiments, as shown in FIGS. 14 and 15, the projection screen can further include an adhesive layer 14 located between the second diffusion layer 11’ and the Fresnel lens layer 12, for fixing the second diffusion layer 11’ and the Fresnel lens layer 12 to each other. The adhesive layer 14 can be made of an adhesive material such as epoxy resin, acrylic resin, silicone resin, etc., which is not limited herein.

[0085] The second diffusion layer 11' can include a second substrate 111 and a diffusion material layer 112 on the second substrate 111. The first substrate 122 and the second substrate 111 can be made of the same or different materials, including but not limited to Polyethylene Terephthalate (PET), Polyethylene Naphthalate (PEN), Polycarbonate (PC), Polymethyl Methacrylate (PMMA), Triacetylcellulose (TAC), Cyclo Olefin Polymer (COP), Thermoplastic Polyurethane (TPU), Polyvinyl chloride (PVC), Polyimide (PI), Polyamide (PA), Polyethylene (PE), Polypropylene (PP), and the like.

[0086] The diffusion material layer 112 can be made of a resin material containing diffusion particles or an inorganic material. The diffusion particles can include, but are not limited to, silica particles, aluminum oxide particles, titanium oxide particles, cerium oxide particles, zirconium oxide particles, tantalum oxide particles, zinc oxide particles, magnesium fluoride particles, and the like. The diffusion material layer 112 can be made by various coating methods, which are not limited herein.

[0087] The first diffusion layer K can be formed on the surface of either of the first substrate 122 and the second substrate 111. As shown in FIG. 14, the first diffusion layer K can be formed on the surface of the first substrate 122, and the adhesive layer 14 adheres the second substrate 111 and the first diffusion layer K to each other. As shown in FIG. 15, the first diffusion layer K can also be formed on the surface of the second substrate 111, and the adhesive layer 14 adheres the first substrate 122 and the first diffusion layer K to each other.

[0088] In some embodiments, as shown in FIGS. 16 and 17, the first diffusion layer K can also be formed on a separate substrate, which is referred to as a third substrate g. The first diffusion layer K is first formed on the third substrate g, and then the third substrate is adhered to the second diffusion layer 11' and the Fresnel lens layer 12.

[0089] The third substrate g can be made of the same material as the first substrate 122 and the second substrate 111. Notably, if the first diffusion layer K is formed on the third substrate g first, and then the three functional layers are bonded to each other, two adhesive layers, i.e., the first adhesive layer 141 and the second adhesive layer 142 in FIGS. 16 and 17, are needed, more process steps are needed, and the third substrate g also increases the cost. However, the first diffusion layer K is formed on the third substrate g, and the third substrate g with the first diffusion layer K can be used in combination with the original film layer without changing the original structure, and the application scenarios are more flexible. Therefore, different structures can be used according to the application scenarios of the projection screen in specific implementations, which are not limited herein.

[0090] In some embodiments, the adhesive layer 14 can also be colored, so that the adhesive layer 14 has certain light absorption performance, and the black display effect is improved by adding a coloring material.

[0091] Based on the same inventive concept, the embodiments of the present application also provide a projection system, as shown in FIG. 1, which includes a projection device 2 and a projection screen 1 located on the light exit side of the projection device 2.

[0092] FIG. 18 is a structural schematic diagram of a projection device provided by the embodiments of the present application.

[0093] As shown in FIG. 18, the projection device includes a light source device 21, an illumination light path 22, a display element 23, and a lens 24. The illumination light path 22 is located on the light exit side of the light source device 21, the display element 23 is located on the light exit side of the illumination light path 22, and the lens 24 is located on the light exit side of the display element 23.

[0094] The light source device 21 can adopt a laser light source device. The laser light source device can adopt a monochromatic laser or a laser that can emit multiple colors of laser light or multiple lasers that emit different colors of laser light. When the laser light source device adopts a monochromatic laser, the laser display device also needs to be provided with a color wheel. The color wheel is used for color conversion, and the monochromatic laser cooperates with the color wheel to achieve the purpose of emitting different color base light in time sequence. When the laser light source device adopts a laser that can emit multiple colors of laser light, the laser light source needs to be controlled to emit different colors of laser light as base light in time sequence.

[0095] In the embodiments of the present application, the light source device can adopt a three-color laser light source device. The three-color laser light source device can be a laser that emits three primary colors of laser light, such as an MCL laser, etc. Alternatively, the three-color laser light source device can include a red laser, a green laser, and a blue laser that respectively emit three primary colors of laser light. The three-color laser light source device is beneficial to improve the color gamut of the projected image, has better color performance, and can accurately reproduce the input image.

[0096] The illumination light path 22 is located on the light exit side of the light source device 21, and collimates the light emitted by the light source device 21 and makes the light emitted by the light source device 21 incident on the display element 23 at a suitable angle.

[0097] The display element 23 is used to modulate the incident light. In a specific implementation, the display element 23 can be a digital micromirror device (DMD). After passing through the illumination light path 22, the light beam meets the illumination size and incident angle required by the DMD. The DMD surface includes a large number of tiny mirrors, each of which can be individually driven to deflect. By controlling the deflection angle of the DMD, the brightness of the light incident on the lens 24 is controlled.

[0098] The lens 24 is used to image the light emitted by the display element 23, and the imaging is projected after passing through the lens 24.

[0099] In the embodiments of the present application, the projection device 2 can use an ultra-short focus projection device, that is, the lens 24 in the projection device uses an ultra-short focus lens. The use of an ultra-short focus projection device can greatly shorten the distance between the projection device 2 and the projection screen 1, and realize large-size image display while shortening the projection distance.

[0100] The projection screen 1 is located on the light exit side of the lens in the projection device. The projection screen 1 includes a Fresnel lens layer, a reflective structure layer located on the surface of each lens unit of the Fresnel lens layer, and a first diffusion layer located on the side of the Fresnel lens layer away from the reflective structure layer. The first diffusion layer has the property of angle-selective diffusion of incident light, and only has a diffusion effect on light with a specific range of incident angles, and the diffusion effect on light with other incident angles is greatly reduced.

[0101] After the projection light is incident on the projection screen, it first passes through the first diffusion layer, and the incident angle does not meet the angle range selected by the first diffusion layer, so the projection light does not diffuse after passing through the first diffusion layer, and the incident angle when incident on the reflective structure layer meets the original design value, so that it can be efficiently reflected by the reflective structure layer; the reflected projection light is incident on the first diffusion layer again, and the incident angle at this time meets the angle range selected by the first diffusion layer, so that the reflected projection light is diffused and emitted after passing through the first diffusion layer, thereby increasing the diffusion angle of the projection light and achieving the purpose of expanding the viewing angle.

[0102] The addition of the first diffusion layer with the property of angle-selective diffusion in the projection screen can better play the role of the reflective structure layer, so that the projection screen has higher contrast.

[0103] While the preferred embodiments of the application have been described, additional variations and modifications can be made to these embodiments by those skilled in the art once they have the benefit of the present disclosure without departing from the spirit and scope of the application. Accordingly, it is intended that such additions and modifications be included within the scope of the application. It is the following claims, including any amendments thereto, which define the scope of the application.

[0104] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A projection screen, comprising: A Fresnel lens layer; the Fresnel lens layer includes multiple lens units, each lens unit including a lens surface and a non-lens surface; the lens surface is inclined relative to the plane of the projection screen. A reflective structure layer covers at least the lens surface of each of the lens units; the reflective structure layer has a higher reflectivity for the projected light emitted from the projection device than for light of other wavelengths. The first diffusion layer is located on the side of the Fresnel lens layer opposite to the reflective structure layer; The projection light emitted from the projection device is incident on the projection screen. It first enters the first diffusion layer, and after being diffused for the first time by the first diffusion layer, it enters the Fresnel lens layer. After being reflected by the wave reflection structure layer on the surface of each lens unit of the Fresnel lens layer, it enters the first diffusion layer again, and is diffused for the second time by the first diffusion layer before being emitted. The degree of diffusion of the projection light by the first diffusion layer in the first diffusion layer is less than the degree of diffusion of the projection light by the second diffusion layer.

2. The projection screen as described in claim 1, further comprising: The second diffusion layer is located on the side of the first diffusion layer that is away from the Fresnel lens layer; The second diffusion layer diffuses light rays incident at any angle.

3. The projection screen as described in claim 2, wherein, The haze of the second diffusion layer is 2% to 10%.

4. The projection screen as described in claim 1, wherein, The first diffusion layer is a light-transmitting medium layer, which includes a plurality of micro-bodies. The length of the micro-bodies along the thickness direction of the light-transmitting medium layer is greater than the length along the direction parallel to the plane of the light-transmitting medium layer. The refractive index of the microbody is different from that of the light-transmitting medium layer.

5. The projection screen as described in claim 4, wherein, The microbody has a columnar structure, and the axial direction of the columnar structure is parallel to the thickness direction of the light-transmitting medium layer.

6. The projection screen as described in claim 4, wherein, The plurality of micro-body particles are particles dispersed in the light-transmitting medium layer, and the length of the particles along the thickness direction of the light-transmitting medium layer is greater than the length along the direction parallel to the plane of the light-transmitting medium layer.

7. The projection screen as described in any one of claims 4 to 6, wherein, The first diffusion layer diffuses light incident at a set angle range to a greater extent than light incident at other angles. The degree of diffusion of light incident within the set angle range by the first diffusion layer increases with the increase of the difference in refractive index between the light-transmitting medium layer and the microbody; The refractive index of the light-transmitting medium layer differs from that of the microbody by 0.02 to 0.

05.

8. The projection screen as described in claim 7, wherein, The refractive index of the light-transmitting medium layer is 1.48 to 1.

50.

9. The projection screen as described in any one of claims 4 to 6, wherein, The first diffusion layer diffuses light incident at a set angle range to a greater extent than light incident at other angles. The degree of diffusion of light incident within the set angle range by the first diffusion layer increases with the increase of the thickness of the first diffusion layer; The thickness of the first diffusion layer is 10 μm to 100 μm.

10. The projection screen according to any one of claims 4 to 6, wherein, The first diffusion layer diffuses light incident at a set angle range to a greater extent than light incident at other angles. The degree of diffusion of light incident within the set angle range by the first diffusion layer increases with the increase of the frequency of the change in refractive index of the light-transmitting medium layer and the microbody; In a cross-section parallel to the plane of the light-transmitting medium layer, the length of the microbody in the horizontal direction is less than its length in the vertical direction; the horizontal direction and the vertical direction are perpendicular to each other.

11. The projection screen as claimed in claim 10, wherein, In a cross-section parallel to the plane of the light-transmitting medium layer, the length of the micro-body is 1μm to 10μm, and the spacing between adjacent micro-bodies is 2μm to 5μm.

12. The projection screen as claimed in claim 7, 9, or 10, wherein, The set angle range is -10° to 10°.

13. The projection screen as described in any one of claims 2 to 6, further comprising: An adhesive layer is located between the second diffusion layer and the Fresnel lens layer; The first diffusion layer is located between the adhesive layer and the Fresnel lens layer; Alternatively, the first diffusion layer may be located between the second diffusion layer and the adhesive layer.

14. The projection screen as described in any one of claims 2 to 6, wherein, The projection screen has a horizontal diffusion angle of 20° to 45° and a vertical diffusion angle of 10° to 25°; the horizontal and vertical directions are perpendicular to each other.

15. A projection system, comprising: Projection equipment, used to emit projection light; and A projection screen is located on the light-emitting side of the projection device, and the projection screen is the projection screen according to any one of claims 1 to 14.

16. The projection system of claim 15, wherein, The projection device is an ultra-short-throw laser projection device; the projection device includes: A three-color laser source device for emitting three primary color lasers; A display element, located on the light-emitting side of the three-color laser source device, is used to modulate the emitted laser light from the three-color laser source device to form a display image; and The lens is located on the light-emitting side of the display element.

Images