A rollable projection screen and projection system

Abstract

The application discloses a kind of rollable projection screen and projection system, including at least two functional layers, adjacent functional layer is bonded using adhesive layer.The material of adhesive layer uses viscous fluid, and the viscous fluid material has flowability, so that the stress generated during the winding process of the screen can make it flow when it is applied to the viscous fluid, thereby dispersing the generated stress, so that the screen is always in the stage of elastic deformation under the winding state.The screen can still recover its original shape when the external force is removed in the unwinding state, avoiding permanent deformation of the screen, so that the screen will not warp and roll marks.

Description

Technical Field

[0001] This invention relates to the field of projection technology, and more particularly to a rollable projection screen and projection system. Background Technology

[0002] In recent years, with the continuous increase in monitor size, projection display products, as large-screen display products that can replace LCD TVs and OLED TVs in terms of power consumption, weight, and size, are experiencing rapid market expansion. Laser TVs, in particular, which utilize ultra-short-throw projection equipment, are seeing rapid market growth due to their high image quality, large screen size, light weight, and ease of transport.

[0003] Projection devices can be used with projection screens to achieve higher gain. The projector emits projection light, which enters the projection screen, is reflected by the screen, and then enters the viewer's eye to see the projected image. The projection screen is made of flexible material and can be rolled up when not projecting an image, making it a product with excellent space design features and suitable for installation in existing homes.

[0004] However, rollable projection screens require multiple roll-up and unroll-down operations, which can easily cause plastic deformation, resulting in unsightly defects such as curl marks or stripes. Summary of the Invention

[0005] This invention provides a rollable projection screen, comprising:

[0006] At least two functional layers; and

[0007] An adhesive layer, located between adjacent functional layers, is used to bond the adjacent functional layers together.

[0008] The adhesive layer is made of a viscous fluid material.

[0009] In some embodiments of the present invention, a frame structure is provided at the edge between adjacent functional layers for accommodating and confining the viscous fluid material.

[0010] In some embodiments of the present invention, a flow-limiting structure is provided between adjacent functional layers to define the flow path of the viscous fluid material.

[0011] In some embodiments of the present invention, the current limiting structure is a plurality of columnar structures, the axis of which is parallel to the normal of the plane in which the rollable screen is located.

[0012] In some embodiments of the present invention, the height of the columnar structure is equal to the distance between adjacent functional layers, and the plurality of columnar structures are evenly distributed between adjacent functional layers.

[0013] In some embodiments of the present invention, the height of the columnar structure is less than the distance between adjacent functional layers, and the plurality of columnar structures are staggered between adjacent functional layers.

[0014] In some embodiments of the present invention, the viscous fluid material is one or more of water, aqueous solution or oil.

[0015] In some embodiments of the present invention, the product of the refractive index and the thickness of the viscous fluid material is 110 to 130.

[0016] In some embodiments of the present invention, the viscous fluid material is doped with microparticles or needle-like crystals to alter the optical path.

[0017] In some embodiments of the present invention, the transmittance of the adhesive layer is 50% or more.

[0018] In some embodiments of the present invention, the at least two functional layers include:

[0019] diffusion layer; and

[0020] A Fresnel lens layer is located on the side of the adhesive layer opposite to the diffusion layer; the Fresnel lens layer includes:

[0021] Multiple lens units, each of which includes a lens surface and a non-lens surface, wherein the lens surface forms a set angle with respect to the plane of the rollable projection screen; and a reflective layer is provided on the lens unit.

[0022] In some embodiments of the present invention, the reflective layer includes:

[0023] A semi-transparent layer is located on the lens unit;

[0024] A reflective layer is located on the side of the semi-transparent layer opposite to the lens unit; and

[0025] A resonant layer is located between the semi-transparent layer and the reflective layer; the resonant layer is used to resonate and enhance the projection light emitted from the projection device and absorb light of other wavelengths.

[0026] This invention also projects a projection system, comprising:

[0027] Projection equipment, used to emit projection light;

[0028] A projection screen is located on the light-emitting side of the projection device; the projection screen is any of the aforementioned rollable projection screens.

[0029] The rollable projection screen and projection system provided in this invention include at least two functional layers, with adjacent functional layers bonded together by an adhesive layer. The adhesive layer is made of a viscous fluid. The viscous fluid has fluidity, so when the stress generated during the screen's rolling process is applied to the viscous fluid, it can cause the fluid to flow, thereby dispersing the stress. Thus, the screen remains in an elastic deformation stage during the rolled-up state, and can return to its original shape when the external force is removed during the unrolling state, preventing permanent deformation and ensuring the screen does not warp or develop curl marks. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the projection system provided in an embodiment of the present invention;

[0032] Figure 2 One of the schematic diagrams of a planar structure of a rollable projection screen provided in an embodiment of the present invention;

[0033] Figure 3 A second schematic diagram of the planar structure of a rollable projection screen provided in an embodiment of the present invention;

[0034] Figure 4 A schematic diagram of the cross-sectional structure of a rollable projection screen provided in an embodiment of the present invention;

[0035] Figure 5 This is one of the stress-strain curves provided in the embodiments of the present invention;

[0036] Figure 6 This is the second stress-strain curve provided in the embodiments of the present invention;

[0037] Figure 7 This is one of the structural schematic diagrams of a rollable projection screen provided in an embodiment of the present invention;

[0038] Figure 8 This is a second schematic diagram of the structure of a rollable projection screen provided in an embodiment of the present invention;

[0039] Figure 9 This is the third schematic diagram of the structure of the rollable projection screen provided in the embodiment of the present invention;

[0040] Figure 10 This is a schematic diagram of the planar structure of the Fresnel lens layer provided in an embodiment of the present invention;

[0041] Figure 11 A schematic diagram of the cross-sectional structure of the reflective layer provided in an embodiment of the present invention;

[0042] Figure 12 One of the schematic diagrams of the diffusion structure provided in the embodiments of the present invention;

[0043] Figure 13 This is a second schematic diagram of the diffusion structure provided in an embodiment of the present invention;

[0044] Figure 14 This is a schematic diagram of the projection device provided in an embodiment of the present invention. Detailed Implementation

[0045] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. Terms describing position and direction in the present invention are illustrative based on the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of the present invention. The accompanying drawings of the present invention are for illustrative purposes only and do not represent actual proportions.

[0046] With the increasing popularity of laser display products, the market for laser TVs, as a large-screen alternative to LCD and OLED TVs, is rapidly expanding. To achieve better brightness and display effects, projection equipment is typically used in conjunction with a projection screen.

[0047] like Figure 1 As shown, the projection system includes: a projection device 2 and a projection screen 1.

[0048] The projection screen 1 is located on the light-emitting side of the projection device 2, and the audience faces the projection screen 1. The projection device 2 emits projection light, which enters the projection screen 1, passes through the projection screen 1, and exits towards the audience, thus allowing the audience to view the projected image.

[0049] When the projection device 2 and the audience are located on the same side of the projection screen 1, this projection system is called a front projection system. When the projection device 2 and the audience are located on opposite sides of the projection screen 1, this projection system is called a rear projection system. In a front projection system, the projection device 2 emits projection light onto the projection screen 1, and the projection screen 1 reflects the projection light back to the audience, allowing the audience to view the projected image. In a rear projection system, the projection device 2 emits projection light onto the projection screen 1, and the projection light passes through the projection screen 1 and exits towards the audience, allowing the audience to view the projected image.

[0050] In this embodiment of the invention, the projection screen 1 is a flexible screen. The projection screen 1 can be installed on a wall or hung at a high place. It can be unfolded when in use and rolled up for storage when not in use, saving space.

[0051] Projection devices can be categorized into long-throw, short-throw, and ultra-short-throw projectors for different application scenarios. Taking an ultra-short-throw projector as an example, in use, the projector 2 can be positioned below the projection screen 1, projecting light from below and diagonally upwards onto the projection screen 1; or, the projector 2 can be positioned above the projection screen 1, projecting light from above and diagonally downwards onto the projection screen 1. Because ultra-short-throw projection systems have a smaller throw ratio, they can obtain a larger projected image while reducing the distance between the projector 2 and the projection screen 1, making them ideal for applications such as laser TVs.

[0052] like Figures 1-3 As shown, the projection screen 1 is usually rectangular in shape. When unfolded, its bottom and top sides are usually parallel to the horizontal direction x, and the two sides are parallel to the vertical direction y. The horizontal direction x and the vertical direction y are perpendicular to each other. The horizontal direction x refers to the direction of the horizontal plane, and the vertical direction y refers to the direction perpendicular to the horizontal direction x in the plane where the projection screen is located.

[0053] like Figure 2 and Figure 3 As shown, a scroll g can be connected to one side of the projection screen. Figure 2 The top side is used as an illustration to connect the scroll g. Figure 3 The image shows the bottom side connected to the scroll g. The scroll g can be rotated to wind the projection screen onto it for storage.

[0054] In some embodiments, the scroll g can be connected to the left or right side of the projection screen, thereby allowing the projection screen to be stored horizontally, which is not limited here.

[0055] like Figure 4The diagram shows a cross-sectional structure of a rollable projection screen. The rollable projection screen may include at least two functional layers, distinguished by a first functional layer 11 and a second functional layer 12, and the two functional layers are bonded together by an adhesive layer 13'.

[0056] The functional layer can have functions such as diffusion or gain enhancement according to actual needs, and can also include two or more functional layers, all of which can be bonded together using the same adhesive material. Figure 4 This only illustrates the basic structure of a rollable projection screen.

[0057] The adhesive layer 13' is typically made of adhesive materials such as epoxy resin, acrylic resin, or silicone. The adhesive layer 13' can be formed by coating and then curing. When both the functional layer and the adhesive layer 13' are made of flexible materials, the screen can be rolled up. During the winding and unwinding process, the stress on the screen satisfies the following:

[0058] σ = E × ε;

[0059] Where σ represents normal stress, which is the force per unit area, E represents Young's modulus, and ε represents normal strain, which is the relative deformation of an object under the action of external force.

[0060] like Figure 5 As shown, in the early stages of external force application, there is a direct proportional relationship between stress σ and strain ε in the film layer of the screen. The greater the relative deformation of the film layer, the greater the stress; the smaller the relative deformation of the film layer, the smaller the stress. Furthermore, during this stage, the film layer undergoes elastic deformation, and can return to its original shape after the external force is removed. This process approximates the stress experienced by a rollable projection screen in its retracted state.

[0061] like Figure 5 and Figure 6 As shown, when the strain ε exceeds the elastic limit (point a), the film layer undergoes plastic deformation. In this case, the strain still exists when the external force is removed. This means that even if the external force is removed by unwinding, the strain still exists in a screen that has undergone plastic deformation during the winding process. This will lead to permanent deformation of the screen, resulting in appearance defects such as curl marks or stripes.

[0062] To overcome the above problems, embodiments of the present invention provide a rollable projection screen, such as... Figure 7 As shown, the rollable projection screen includes at least two functional layers and an adhesive layer 13. To distinguish the two functional layers, they are referred to as the first functional layer 11 and the second functional layer 12.

[0063] The first functional layer 11 can be located on the side closer to the viewer, serving as the outermost film layer of the projection screen, while the second functional layer 12 can be located on the side farther from the viewer. Depending on the needs, the first functional layer 11 and the second functional layer 12 can have different functions, such as increasing the viewing angle and improving gain.

[0064] An adhesive layer is provided between adjacent functional layers to bond them together. In this embodiment of the invention, the adhesive layer 13 is made of a viscous fluid material 131. When a traditional adhesive is used between adjacent functional layers, the stress generated during the screen's rolling process is applied to the adhesive. Traditional adhesive materials cannot alleviate the stress, resulting in permanent plastic deformation after exceeding the elastic limit. In this embodiment of the invention, the adhesive layer material is replaced with a viscous fluid material 131. The viscous fluid material 131 has fluidity, so when the stress generated during the screen's rolling process is applied to the viscous fluid, it can cause the fluid to flow, thereby dispersing the stress. Thus, the screen remains in an elastic deformation stage during the rolled-up state, and can still restore its original shape when the external force is removed during the unrolling state, avoiding permanent deformation of the screen and preventing warping and curling marks, resulting in good flatness.

[0065] like Figure 7 As shown, since the viscous fluid material has fluidity, in order to accommodate the viscous fluid material 131, a frame structure 132 can be provided at the edge between adjacent functional layers to accommodate and confine the viscous fluid material 131.

[0066] In some embodiments, the resin material to be cured can be coated at the four corners or edges of the surface of any one or two adjacent functional layers, and then the two functional layers are put together to cure the resin material to be cured, thereby forming the above-mentioned frame structure 132.

[0067] Specifically, the frame structure 132 can be made of thermosetting or photocuring materials. For example, UV resin can be formed at the four corners of the functional layer using a syringe or compact dispenser, and then the functional layer can be cured by UV irradiation to create the frame structure 132 to prevent leakage of viscous fluid materials.

[0068] After the frame structure 132 is fabricated, the adjacent functional layers and the frame structure 132 form a cavity for containing the viscous fluid material, into which the viscous fluid material 131 is then injected. In some embodiments, a valve may be provided at the upper or lower part of the frame structure 132. Figure 7 (Not shown in the image) This valve is used to inject viscous fluid materials. It is a one-way valve type, designed to prevent viscous fluid materials from leaking out of the rollable projection screen.

[0069] The adhesive layer 13 is made of a viscous fluid material, which has fluidity. Under the action of gravity or external forces, the viscous fluid material may be unevenly distributed. Therefore, in this embodiment of the invention, such as... Figure 8 and Figure 9 As shown, a flow-limiting structure 133 can be set between adjacent functional layers to restrict the flow path of the viscous fluid material 131. Typically, the screen is suspended high up, and under gravity, the viscous fluid material accumulates at the bottom of the screen. During projection display, the projection light is a laser with high energy; prolonged exposure to the screen may cause expansion. By setting the flow-limiting structure 133 in the rollable projection screen, it can support adjacent functional layers and restrict the flow path of the viscous fluid. When the viscous fluid is subjected to external force, it can flow along a specific path. Its viscous tension can attract the viscous fluid material near the flow-limiting structure 133, preventing it from accumulating in a large amount at one location, thus avoiding unevenness and thermal expansion problems.

[0070] In some embodiments, such as Figure 8 and Figure 9 As shown, the flow-limiting structure 133 consists of multiple columnar structures, with the axes of the columnar structures parallel to the normal to the plane of the rollable screen. After the viscous fluid material 131 is injected into the cavity between the functional layers, it flows between the columnar structures. The distribution of the columnar structures can affect the amount of viscous fluid material and prevent screen deformation during the screen rolling process.

[0071] In some embodiments, such as Figure 8 As shown, the height of the columnar structure (current limiting structure 133) can be equal to the distance d between adjacent functional layers, and multiple columnar structures are evenly distributed between adjacent functional layers.

[0072] The height of the columnar structure can be equal to the distance d between the functional layers. This columnar structure helps maintain a constant distance between the functional layers, resulting in good screen flatness and preventing dents or bumps caused by the flow of viscous fluid materials. Furthermore, the viscous fluid material can flow between the gaps in the columnar structure, which can suppress the amount of viscous fluid material used. This allows for the selection of higher-cost viscous fluid materials, thereby improving the overall performance of the screen.

[0073] In some embodiments, such as Figure 9 As shown, the height of the columnar structure (current limiting structure 133) can be less than the distance d between adjacent functional layers, and multiple columnar structures are staggered between adjacent functional layers.

[0074] The height of the columnar structure can be less than the distance d between the functional layers, and they are respectively set on the surface of the two functional layers. After the two functional layers are joined together, the columnar structure forms an interlaced distribution, which can make the flow path of the viscous fluid material more complex and is beneficial to the dispersion of the viscous fluid material.

[0075] In practice, the columnar structure (flow-limiting structure 133) can be made of the same material as the frame structure 132 and fabricated simultaneously with the frame structure 132. When the columnar structures are staggered on the surfaces of two functional layers, columnar structures need to be fabricated on each of the two functional layers before the two functional layers are joined together. The material and specific fabrication method of the columnar structure are not limited here.

[0076] In this embodiment of the invention, the viscous fluid material 131 can be one or more of water, aqueous solution, or oil. These fluid materials can be viscous and can also utilize surface tension to achieve the effect of bonding the functional layer. For example, the viscous fluid material can be water, ink, glycerin, silicone oil, rapeseed oil, algal oil, etc. The material used in practical applications needs to be selected based on the material's optical properties.

[0077] The adhesive layer 13 is the intermediate film layer of the rollable projection screen. After the projection light is incident on the adhesive layer, it needs to be further incident on the film layer behind it. Therefore, it is necessary to ensure that the adhesive layer 13 has good transmittance. In this embodiment of the invention, the transmittance of the adhesive layer 13 needs to be maintained above 50%. The transmittance and reflectance of the film layer for a specific wavelength of light are related to the optical path difference generated by the light on the surface of the film layer. In this embodiment of the invention, controlling the product of the refractive index n and the thickness d of the viscous fluid material 131 within the range of 110 to 130 can maintain the transmittance of light above 50%, which is roughly the same as the optical characteristics of screens using conventional adhesives.

[0078] In practical implementation, the viscous fluid can also be mixed with two or more materials to match the refractive index and other optical properties. The table below shows the refractive index and transmittance of blue light with a center wavelength of 465nm when the adhesive layer uses a conventional adhesive or the viscous fluid material provided in the embodiments of this invention:

[0079] Adhesive layer material Refractive index Transmission rate Traditional adhesives 1.49 >50%@465nm rapeseed oil 1.47 >90%@465nm Oil 1.52 >90%@465nm glycerin 1.47 >90%@465nm water 1.33 >90%@465nm algal oil 1.59 >90%@465nm

[0080] As can be seen from the table above, when the adhesive layer material is replaced with a viscous fluid material, the transmittance of the adhesive layer can usually be maintained above 90%, which is a good transmittance.

[0081] In some embodiments, microparticles or needle-like crystals can be doped into the viscous fluid material 131 to alter the optical path. The microparticles can be organic resins, oxide single crystals, or glass, etc. The needle-like crystals can be whiskers of metals such as Ti or mica, etc. By doping the viscous fluid material with microparticles or needle-like crystals, light undergoes multiple reflections or refractions when incident on the microparticles or needle-like crystals, achieving diffusion, scattering, or other purposes of the incident light, thereby altering the optical path.

[0082] This invention provides a detailed description of the basic structure of a rollable projection screen, which includes three film layers.

[0083] In some embodiments, the first functional layer 11 may be a diffusion layer and the second functional layer 12 may be a Fresnel lens layer.

[0084] Specifically, the Fresnel lens layer may include a first substrate 122 and a plurality of lens units 121 located on the surface of the first substrate 122.

[0085] The first substrate 122 can be made of materials such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), triacetylcellulose (TAC), cycloolefin polymer film (COP), thermoplastic polyurethane (TPU), polyvinyl chloride (PVC), polyimide (PI), polyamide (PA), polyethylene (PE), and polypropylene (PP), and is not limited here.

[0086] The lens unit 121 is located on the surface of the first substrate 122 and can be made of UV-curable resin. By coating the surface of the first substrate 122 with UV resin, pressing the UV resin with a mold having a Fresnel structure, and simultaneously irradiating with UV, the Fresnel lens structure is transferred onto the first substrate 122.

[0087] Figure 10 This is a schematic diagram of the planar structure of the Fresnel lens layer, as shown below. Figure 7 and 10As shown, the Fresnel lens layer 12 includes multiple lens units 121 arranged according to a set rule. For example... Figure 10 As shown, these lens units 121 can form concentric circles that expand sequentially along the radial direction. When the projection screen is applied to an ultra-short throw projection system, the center O of the concentric lens units 121 is usually not located within the projection screen. When the projection device emits projection light from below the projection screen, the center O of each lens unit 121 is located below the bottom side of the projection screen and on the extension line of the projection screen's axis of symmetry I-I'. Along the projection screen from bottom to top, the radius of the lens units 121 gradually increases, and the projection screen does not contain complete circular lenses, but only partially arc-shaped lenses.

[0088] like Figure 7 As shown, each lens unit 121 includes an interconnected lens surface x1 and a non-lens surface x2. The lens surface x1 is tilted relative to the plane of the projection screen, and the tilt angle of the lens surface x1 is set according to the incident direction of the projected light and the desired exit direction of the light. A reflective layer F is covered on the lens surface x1 of the lens unit 121, so that when the projected light is incident on the reflective layer F on the lens surface x1, it can be reflected in the direction of the viewer. 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.

[0089] The reflective layer F covers at least the lens surface x1 of each lens unit 121 of the Fresnel lens layer 12. Since the tilt angle of the lens surface x1 of each lens unit 121 is in the direction of reflecting the incident projection light toward the viewer, and the reflective layer F covers the lens surface x1 of the lens unit 121 and has the same tilt angle as the lens surface x1, the incident projection light can be reflected toward the viewer as originally designed.

[0090] By setting a Fresnel lens layer 12 in the projection screen and covering the lens surface x1 of each lens unit 121 of the Fresnel lens layer with a reflective layer F, it is beneficial to reflect the projection light towards the front of the projection screen, thereby improving the gain of the projection screen.

[0091] When viewing a projection screen in strong light, it is easily affected by ambient light. Therefore, watching movies or other images that frequently use dark scenes in bright ambient light will reduce image contrast and affect the viewing experience.

[0092] In view of this, the reflective layer F on the surface of the Fresnel lens layer 12 can be replaced with a wavelength-selective reflective layer. The wavelength-selective reflective layer F utilizes the principle of resonant enhancement of light of a set wavelength to selectively enhance the reflection of the projection light emitted from the projection device, while absorbing light of other wavelengths. This makes the reflectivity of the reflective layer F for the projection light emitted from the projection device greater than its reflectivity for other wavelengths, thus achieving a black appearance when the projection device is off and a bright display when the projection device is on, thereby significantly improving the contrast of the projected image.

[0093] Specifically, such as Figure 11 As shown, the wavelength-selective reflective layer F comprises a semi-transparent layer f1, a reflective layer f2, and a resonant layer f3. The semi-transparent layer f1, the resonant layer f3, and the reflective layer f2 are sequentially formed on the lens surfaces of each lens unit of the Fresnel lens layer. The semi-transparent layer f1, the resonant layer f3, and the reflective layer f2 constitute a resonant structure.

[0094] The semi-transparent layer f1 has semi-transparent and semi-reflective properties. It should be noted that the semi-transparent and semi-reflective properties mentioned in this embodiment do not mean that the transmittance and reflectance of light are both 50%. Rather, it indicates that the semi-transparent layer f1 can achieve the property of partially transmitting and partially reflecting light. Its transmittance and reflectance can be adjusted according to actual requirements, and the specific transmittance and reflectance of the semi-transparent layer f1 are not limited here. The semi-transparent layer f1 allows the projected light to enter the resonant structure when it is incident on the projection screen, and after the projected light oscillates and intensifies within the resonant structure, it can also exit through the semi-transparent layer f1.

[0095] In practical implementation, the semi-transparent layer f1 can be a laminated structure formed by at least one or more metals selected from Al, Nb, Ag, and Ti. The thickness of the semi-transparent layer f1 can be controlled between 2nm and 20nm, so that the semi-transparent layer f1 has a certain degree of light transmittance, while also having reflectivity.

[0096] The reflective layer f2 has the function of reflecting light. Since the reflective layer f2 is located on the side away from the audience, it does not need to transmit light. Therefore, it can be made of a material that has reflective properties but no light transmission properties.

[0097] In practice, the reflective layer f2 can be made of materials such as Al, aluminum alloy, Ag, or silver alloy, and the thickness of the reflective layer f2 is greater than the thickness of the semi-transparent layer f1. The thickness of the reflective layer f2 needs to be greater than 50 nm to ensure that the reflective layer f2 has better reflection efficiency.

[0098] The resonant layer f3 is located between the semi-transparent layer f1 and the reflective layer f2, and the product of the thickness and refractive index of the resonant layer f3 determines the cavity length of the resonant structure. Therefore, when designing the resonant structure, it is necessary to select a dielectric material whose product of refractive index and thickness satisfies the condition for the projection light emitted from the projection device to generate resonance.

[0099] In practice, the resonant layer f3 can be made of materials such as metal oxides, nitrides or transparent resins.

[0100] If the reflectance of the semi-transparent layer f1 is r H The transmittance is t H The reflectivity of reflective layer f2 is r M Let the incident electric field intensity on the wavelength-selective reflective layer be Ei, and the electric field intensity of the reflected light be Er, then:

[0101]

[0102]

[0103] When the resonance becomes the maximum phase:

[0104] m is a natural number.

[0105] If we use the cavity length relationship of the resonant structure, it can be rewritten as:

[0106] 2nL=mλ; m is a natural number.

[0107] Where n is the refractive index of the resonant layer and L is the optical thickness of the resonant layer.

[0108] As can be seen from the above relationship, when a dielectric material with a suitable refractive index is selected as the resonant layer and the resonant layer is set to a suitable optical thickness, the reflection of projected light by the resonant cavity can be enhanced.

[0109] In this embodiment of the invention, the projection light source can be a three-color laser light source device, which can emit red laser, green laser and blue laser. By adjusting the refractive index and optical thickness of the resonant layer, the resonant cavity can simultaneously enhance the reflection of red laser, green laser and blue laser and attenuate the reflection of other wavelengths of light, thereby improving the contrast of the projected light.

[0110] In some embodiments, the first functional layer 11 can be a diffusion layer, which can diffuse light, thereby increasing the divergence angle of the light emitted from the projection screen and thus increasing the viewing angle of the screen.

[0111] The diffusion layer may include a second substrate and a diffusion structure located on the surface of the second substrate.

[0112] The second substrate can be made of polyester film (such as polyethylene terephthalate film), polyolefin film (such as polyethylene film and polypropylene film), cellulose film (such as triacetyl cellulose film), and polyimide film. Alternatively, the second substrate can also be made of waterproof paper, transparent or semi-transparent cellophane, or composite paper.

[0113] Diffusion structures can achieve isotropic or anisotropic diffusion. Isotropic diffusion means that the degree of diffusion of incident light is approximately the same in all directions; anisotropic diffusion means that the degree of diffusion of light can be different in different directions.

[0114] In this embodiment of the invention, the anisotropic diffusion layer diffuses light more effectively along the horizontal direction x than along the vertical direction y. Projection screens are typically fixed to a wall or suspended high up, or integrated with the projection device. The horizontal direction x refers to the direction parallel to the viewer's horizontal plane, and the vertical direction y is perpendicular to the horizontal direction x. Since viewers do not require a large viewing angle in the vertical direction when viewing a projection screen, but do need a large viewing angle in the horizontal direction to expand the visible range, the anisotropic diffusion layer can diffuse the light's diffusion angle in the horizontal direction, thereby expanding the visible range of the projected image.

[0115] To achieve the characteristics of anisotropic diffusion, multiple strip-shaped ridge structures 111 can be set, such as... Figure 12 As shown, the strip-shaped ridge structure 111 can adopt a lenticular structure, or, as... Figure 13 As shown, the strip-shaped prism structure 111 can adopt a prism structure. For example... Figure 12 and Figure 13 As shown, the axis of the strip-shaped rib structure 111 is parallel to the vertical direction y, and is arranged sequentially along the horizontal direction x.

[0116] The isotropic or anisotropic diffusion structure located on the surface of the second substrate can be made by embossing materials such as acrylic resin or thermoplastic polyurethane (TPU), or by UV resin materials through UV curing. No limitation is made here.

[0117] In some embodiments, the rollable projection screen may also include three or more functional layers, and adjacent functional layers may be bonded together by an adhesive layer. Each adhesive layer uses the aforementioned viscous fluid material to ensure that the rollable projection screen still has good flatness after multiple roll-ups and unrolls and will not warp or curl.

[0118] For example, a polarization layer can also be set in a rollable projection screen. The polarization layer can be set inside the screen and bonded to the other functional layers on both sides through the aforementioned adhesive layer 13. The polarization layer only transmits linearly polarized light whose polarization direction is parallel to its polarization axis; light with other polarization directions is absorbed. When the projection device uses a laser light source, the laser emitted by the projection device is linearly polarized light. To improve the contrast of the projected light, a polarization layer can be set inside the projection screen so that the projected light can pass through the polarization layer, while light with other polarization directions cannot pass through the polarization layer.

[0119] Additionally, a speckle reduction film can be incorporated into the rollable projection screen. When using a laser light source, the strong coherence of the laser can easily cause speckle problems, affecting display quality. By incorporating a speckle reduction film into the screen, the impact of speckle on image quality can be reduced. Specifically, this film can mix in diffusion particles to increase the random phase of the laser, thereby reducing speckle. The speckle reduction film can be used independently or mixed into an existing film; this is not a limitation.

[0120] The fewer functional layers a rollable projection screen includes, the thinner it is. In this case, the bulkiness during winding can be reduced by decreasing the diameter of the roll core. Depending on the winding method, the diameter of the roll core for a rollable projection screen can reach 60mm.

[0121] Based on the above-described inventive concept, this invention also includes comparative experiments on screens using traditional adhesives and those using viscous fluid materials. To verify the impact of the adhesive layer material on the rollable projection screen, the screens in the comparative experiments all adopted the most basic three-layer structure, with the adhesive layer located in the middle, and the two functional layers replaced only by the material of their substrates. The substrate of the functional layers was PET.

[0122] Screen 1:

[0123] Apply silicone oil to a PET film cut to a length of 380mm and a width of 20mm. Use silicone oil with a thickness of 10μm to bond two PET layers, each 250μm thick. Staple the edges of the three layers of film together to prevent shifting.

[0124] When the three layers of film were wound onto a PVC pipe (as a reel), it was observed that the PET film shifted by approximately 4 mm during the winding process. No shifting occurred after unwinding, and no issues with curl marks or flatness were observed.

[0125] Screen 2:

[0126] Two layers of PET of the same size are bonded together using a conventional adhesive. The first PET layer is 188 μm thick, the second PET layer is 250 μm thick, and the conventional adhesive is 188 μm thick.

[0127] When the three layers of film are wound and unwound, curl marks will appear, and the adhesive material and PET will curl and bend.

[0128] Screen 3:

[0129] Two layers of PET of the same size are bonded together using a conventional adhesive. The thickness of the first PET layer is 188 μm, the thickness of the second PET layer is 188 μm, and the thickness of the conventional adhesive is 188 μm.

[0130] When the three layers of film are wound up and unwound, curl marks will appear.

[0131] This shows that the adhesive layer of screen one uses a viscous fluid material, while the adhesive layers of screens two and three use traditional adhesive materials. Even with changes in the thickness of the PET and traditional adhesive materials, curling marks still appear after repeated winding and unwinding of the screens in screens two and three. Therefore, the choice of adhesive layer material affects the screen's deformation and flatness. Replacing the adhesive layer material with a viscous fluid material can avoid problems such as curling marks and stripes, maintaining good screen flatness.

[0132] Based on the same inventive concept, embodiments of the present invention also provide a projection system, such as... Figure 1 As shown, the projection system includes: a projection device 2 and a rollable projection screen 1 located on the light-emitting side of the projection device 2.

[0133] Figure 14 This is a schematic diagram of the projection device provided in an embodiment of the present invention.

[0134] like Figure 14 As shown, 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-emitting side of the light source device 21, the display element 23 is located on the light-emitting side of the illumination light path 22, and the lens 24 is located on the light-emitting side of the display element 23.

[0135] The light source device 21 can be a laser light source device. The laser light source device can be a monochromatic laser, a laser capable of emitting multiple colors of laser light, or multiple lasers emitting different colors of laser light. When the laser light source device uses a monochromatic laser, the laser display device also needs to include a color wheel for color conversion. The monochromatic laser, in conjunction with the color wheel, can achieve the purpose of emitting different primary colors of light in a sequential manner. When the laser light source device uses a laser capable of emitting multiple colors of laser light, it is necessary to control the laser light source to emit different colors of laser light as primary colors in a sequential manner.

[0136] In this embodiment of the invention, the light source device can be a three-color laser light source device. This device can be a laser that emits three primary colors of laser light, such as an MCL laser; or it can include red, green, and blue lasers that emit the three primary colors of laser light respectively. Using a three-color laser light source device helps to improve the color gamut of the projected image, resulting in better color performance and accurate reproduction of the input image.

[0137] The illumination light path 22 is located on the light-emitting side of the light source device 21. The illumination light path 22 collimates and homogenizes the emitted light from the light source device 21, and also allows the emitted light from the light source device 21 to enter the display element 23 at a suitable angle. The illumination light path 22 may include multiple lenses or lens groups, which are not limited here.

[0138] Display element 23 is used to modulate the incident light. In a specific implementation, display element 23 can be a digital micromirror device (DMD). After passing through illumination path 22, the light beam conforms to the illumination size and incident angle required by the DMD. The DMD surface includes a number of micromirrors, each of which can be individually driven to deflect. By controlling the deflection angle of the DMD, the brightness of the light incident on lens 24 is controlled.

[0139] Lens 24 is used to image the light emitted from display element 23, and the image is then projected.

[0140] In this embodiment of the invention, the projection device 2 can be a long-throw, short-throw, or ultra-short-throw projection device, that is, the lens 24 in the projection device adopts a long-throw, short-throw, or ultra-short-throw lens.

[0141] The rollable projection screen 1 is located on the light-emitting side of the lens in the projection device. The rollable projection screen 1 includes at least two functional layers, and adjacent functional layers are bonded together by an adhesive layer. The adhesive layer is made of a viscous fluid. The viscous fluid material has fluidity, so when the stress generated during the screen's rolling process is applied to the viscous fluid, it can cause the fluid to flow, thereby dispersing the stress. Thus, the screen remains in an elastic deformation stage when rolled up, and when unrolled, it can still return to its original shape after the external force is removed, avoiding permanent deformation of the screen and preventing warping and curling.

[0142] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0143] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A rollable projection screen, characterized in that, include: At least two functional layers; and An adhesive layer, located between adjacent functional layers, is used to bond the adjacent functional layers together. The adhesive layer is made of a viscous fluid material.

2. The rollable projection screen as described in claim 1, characterized in that, The edges between adjacent functional layers are provided with a frame structure for accommodating and confining the viscous fluid material.

3. The rollable projection screen as described in claim 1, characterized in that, A flow-limiting structure is provided between adjacent functional layers to define the flow path of the viscous fluid material.

4. The rollable projection screen as described in claim 3, characterized in that, The current limiting structure consists of multiple columnar structures, the axes of which are parallel to the normal to the plane containing the rollable screen.

5. The rollable projection screen as described in claim 4, characterized in that, The height of the columnar structure is equal to the distance between adjacent functional layers, and the plurality of columnar structures are evenly distributed between adjacent functional layers.

6. The rollable projection screen as described in claim 4, characterized in that, The height of the columnar structure is less than the distance between adjacent functional layers, and the plurality of columnar structures are staggered between adjacent functional layers.

7. The rollable projection screen as described in any one of claims 1 to 6, characterized in that, The viscous fluid material is one or more of water, aqueous solution, or oil.

8. The rollable projection screen as described in claim 7, characterized in that, The product of the refractive index and thickness of the viscous fluid material is 110 to 130.

9. The rollable projection screen as described in claim 7, characterized in that, The viscous fluid material is doped with microparticles or needle-like crystals to alter the optical path.

10. The rollable projection screen as described in claim 9, characterized in that, The transmittance of the adhesive layer is 50% or more.

11. The rollable projection screen as described in any one of claims 1 to 6, characterized in that, The at least two functional layers include: diffusion layer; and A Fresnel lens layer is located on the side of the adhesive layer opposite to the diffusion layer; the Fresnel lens layer includes: Multiple lens units, each of which includes a lens surface and a non-lens surface, wherein the lens surface forms a set angle with respect to the plane of the rollable projection screen; and a reflective layer is provided on the lens unit.

12. The rollable projection screen as described in claim 11, characterized in that, The reflective layer includes: A semi-transparent layer is located on the lens unit; A reflective layer is located on the side of the semi-transparent layer opposite to the lens unit; and A resonant layer is located between the semi-transparent layer and the reflective layer; the resonant layer is used to resonate and enhance the projection light emitted from the projection device and absorb light of other wavelengths.

13. A projection system, characterized in that, include: Projection equipment, used to emit projection light; A projection screen is located on the light-emitting side of the projection device; The projection screen is the rollable projection screen according to any one of claims 1 to 12.

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