KR20070110173A - Projection screen - Google Patents

Abstract

A projection screen is provided to realize various types of screens such as a forward projection type, a backward projection type, a transparent holographic type, and a bidirectional screen using a single diffusion material. A projection screen includes a light-diffusing layer(40) stacked on a transparent plate(10). A part of light transmitted from a transmitting device is diffused, reflected, and changed to diffusive reflected light, while most of the transmitted light is diffused, transmitted, and changed to diffusive transmitted light. In case that the projection screen is used as a backward projection type screen or a transparent holographic screen, the plate is made of a transparent material and the diffusive transmitted light transmitting the light-diffusing layer is transmitted to the rear of the plate.

Description

Projection Screen {PROJECTION SCREEN}

1 is a cross-sectional view of a conventional front projection screen.

2 is a cross-sectional view of a Fresnel lens and a lenticular lens screen of a conventional rear projection screen.

3 is a cross-sectional view of a conventional holographic screen.

4 is a cross-sectional and detailed cross-sectional view of a rear projection screen or transparent holographic screen of one embodiment according to the present invention.

5 is a partial cross-sectional view illustrating a process of forming a light diffusing layer using a mold substrate on the surface of a prism pattern in manufacturing a rear projection screen according to the present invention.

FIG. 6 is a process diagram illustrating a process of manufacturing the projection screen of FIG. 4. FIG.

7 is a cross-sectional view of a rear projection screen of one embodiment according to the present invention.

8-12 and 14 are cross-sectional views of a front projection or bidirectional projection screen of one embodiment according to the present invention.

13 is a manufacturing process diagram of the screen shown in FIG.

15 is a block diagram of a projection TV or a projection monitor assembly to which a rear projection screen according to the present invention is applied.

16 is a block diagram of a second embodiment of the projection TV or projection monitor assembly to which the rear projection screen according to the present invention is applied.

Fig. 17 is an electron micrograph of a cross section and a surface of a light diffusing film having a plurality of convex portions on one outer surface while at the same time a second light diffusing layer applied to a projection screen according to the present invention, that is, a fine light diffusing agent is uniformly dispersed.

18 is a photomicrograph of the surface of an embossed layer applied to a projection screen according to the present invention.

*** Explanation of symbols on the main parts of the drawing ***

1: rear projection screen 2: reflective mirror

3: optical engine 4: lens unit

5: sealing spacer 6: circuit board

10: Substrate 11: Achromatic Substrate

20: substrate 2 30: particulate light diffusing agent

40: light diffusing layer 50: volume hologram layer

60: glass beads 70: glass bead protective layer

80: aluminum deposition layer 90: adhesive layer

100: base material 110: Fresnel lens

120: lenticular lens 130: diffuser

140: light reflection layer 150: second light diffusion layer

160: light absorption layer 170: second light absorption layer

180: embossed layer 190: mold substrate

200: incident light 210: light transmitting layer

300: reflected light 400: projection light

500: light diffusion film

The present invention relates to a projection screen for displaying an image projected from an optical engine such as a projector, and more particularly to a projection screen capable of displaying a wide viewing angle and a high definition image.

Conventional screens for projecting an incident image into a viewing space typically include a front projection screen for reflecting and projecting incident light, a rear projection screen for transmitting incident light, and a holographic screen. Each will be described below with reference to the drawings.

First, the front projection screen is shown in FIG. 1 is a cross-sectional view of a conventional front projection screen, showing a portion of a cross section of the front projection screen. As shown in FIG. 1, the conventional front projection screen is designed to view an image in which incident light 200 projected from the front of the screen is reflected off the surface of the screen and returned in the form of reflected light 300. FIG. Typically, the screen is a substrate 100 such as a white cloth, film and acrylic, etc., the surface of the substrate was processed in various ways to improve the properties of the screen. Specifically, a method of making fine scratches on the surface of the substrate, coating the glass beads 60, or applying the aluminum coating 80, or the like has been used. Reference numeral 70 denotes a glass bead protective layer, and 90 denotes an adhesive layer.

However, one type of matte white screen of the conventional front projection screen has a problem that the brightness of the image is insufficient or that the viewing angle of the glass bead screen is poor. The video looked blurry when watching.

Next, a conventional rear projection screen is shown in FIG. 2 is a cross-sectional view of a Fresnel lens and a lenticular lenticular screen of a conventional rear projection screen, showing a portion of a cross section of the Fresnel lens and lenticular lenticular screen. As illustrated in FIG. 2, the rear projection screen is designed to transmit an image projected from the rear of the screen to project to a viewing space. Simple rear-projection screens have been used to process the surface of transparent film or transparent acrylic in various ways. In detail, coating particles such as glass beads, such as a front projection screen, or forming a number of fine optical lenses, that is, Fresnel lens 110 and lenticular lens 120, as shown in FIG. A method of improving the characteristics of the projection screen has been used.

In the case of the optical lenticular screen, which is a rear projection screen known to have the best performance among the conventional rear screens, that is, the Fresnel and lenticular lenticular screens of FIG. There was a problem in that viewing was difficult, and there was a complicated problem in the manufacturing process, such as requiring a fine printing technology, extrusion technology and coating technology.

Finally, a conventional holographic screen is shown in FIG. 3 is a cross-sectional view of a conventional holographic screen, showing part of a cross section of the holographic screen. As shown in FIG. 3, in the conventional holographic screen, the incident light 200 projected at a predetermined angle from the rear is deflected at a predetermined angle while passing through the volume hologram 50, and then transmitted to the front so that the projection light 400 is viewed in the viewing space. Will be projected to. Such holographic screens have a volume hologram 50 formed between the substrate 1 (10) and the substrate 2 (20), generally forming a relief hologram on the surface of the transparent substrate, or photopolymer or dichromate gelatin in the transparent substrate. After the formation of a layer such as silver halide, it is designed in such a way as to form a volume hologram 50 to which a specific direction is given using a short wavelength ray (for example, a laser ray). Representative examples of such holographic screens include Holopro Screen of Pronova of Germany and Holo Screen of DNP of Japan.

However, in the case of the conventional holographic screen, there is an advantage that the image can be realized without disturbing the inside and outside view, while the viewing angle is not good due to the characteristics of the volume hologram 50 which has given a certain direction, and the manufacturing process is complicated and difficult. There was a problem that the price is very expensive.

SUMMARY OF THE INVENTION The present invention has been presented to solve the above problems, and an object of the present invention is to provide a high contrast ratio and high brightness projection screen displaying a wide viewing angle and a high definition image and further being less affected by external light.

In addition, another object of the present invention is to implement various types of screens such as front projection type, rear projection type (including holographic) and bidirectional screen by changing the reflectance of the screen substrate or the surface state of the diffusion medium with only one type of diffusion medium. It is to provide a screen that can be.

In the present invention, a projection screen having a substrate and a light diffusion layer attached to one surface of the substrate to evenly spread the image to achieve the above object, the light diffusion layer through the light curing of the composition for diffusion medium The composition for diffusion medium is dissolved in water to form a transparent solution, the water-soluble polymer material is 0.5 to 35% by weight based on the total weight, hydrophilic and highly dispersible in water, 31 based on the total weight To 98.5% by weight of the photocurable hydrophilic monomer, and the photocurable hydrophilic monomer to react with the polymer reaction, 0.1 to 5% by weight based on the total weight of the photocurable hydrophilic monomer, photoinitiator, and based on the total weight A projection screen is provided which is a composition comprising a solvent that is 0.5 to 35 weight percent.

Hereinafter, with reference to the accompanying drawings will be described in detail the advantages, features and preferred embodiments of the present invention.

4 is a cross-sectional view of a projection screen of one embodiment according to the present invention, showing a portion of a cross section of a rear projection screen or a transparent holographic screen. The projection screen according to the invention consists of a light diffusing layer 40 stacked on a transparent substrate 10. Part of the projection light projected from the projection apparatus is diffused and reflected to become diffuse reflected light, and most of it is diffused and transmitted to be diffused transmitted light. When the projection screen of FIG. 4 is used as a rear projection screen or a transparent holographic screen, the substrate 10 must be formed of a transparent material, and the diffused transmission light transmitted through the light diffusion layer 40 is transmitted to the rear surface of the substrate 10. (1) a plurality of convex patterns (for example, a concave pattern in the mold and a convex pattern in the light diffusing layer) on the opposite surface not attached to the substrate of the light diffusing layer 40, or (2) the projection distance A prism pattern for shortening, or (3) an uneven pattern for increasing the diffusivity of the projection light, or (4) a smooth surface for maintaining transparency in the case of a transparent holographic screen may be selectively formed.

The outer surface of the light diffusion layer 40 and the substrate 10 which is not attached to the light diffusing layer 40 has anti-glare treatment to prevent glare caused by ambient lighting or sunlight, anti-reflective treatment to prevent light reflection by illumination or sunlight, and eliminates the occurrence of static electricity. It is desirable to have a functional surface treatment including an antistatic treatment, a prism treatment to enhance brightness, and a selective absorption treatment to selectively absorb a specific wavelength.

FIG. 5 is a partial cross-sectional view illustrating a process of forming a light diffusion layer using a mold substrate on a prism pattern surface when manufacturing a rear projection screen according to the present invention. FIG. 6 is a process diagram illustrating a process of manufacturing a projection screen of FIG. 4. to be. Hereinafter, a process of manufacturing the projection screen of FIG. 4 will be described with reference to FIGS. 5 and 6.

The mold substrate 190 is formed (ST100 step). A mold substrate 190 formed of a metal substrate such as aluminum, copper or nickel, a plastic substrate such as acrylic, polycarbonate, or polyethylene terephthalate (aka PET), or a glass substrate is prepared. (1) multiple concave patterns for increasing the viewing angle, or (2) prism patterns for shortening the projection distance, or (3) diffusivity of the projection light, through etching, cutting, corrosion or polishing processes on one side of the mold substrate. Uneven patterns for increasing the number of layers, or (4) smooth surfaces for maintaining transparency. In other words, when used as a transparent holographic screen, one side is placed as a smooth surface and a separate pattern is not formed.

Concave-convex pattern means a form in which concave and convex are arranged regularly or irregularly with respect to the surface. The concave pattern refers to a form that is dug only below the surface relative to the surface, and the convex pattern refers to a form that rises only above the surface relative to the surface. The general uneven pattern has a shape in which concave and convex patterns are mixed and have an irregular arrangement.

After placing the sealing spacer 5 at the edge of the mold substrates 190 (step ST110), after placing the substrate 10 on the sealing spacer 5, the mold substrate 190 and the transparent The edges facing each other of the substrate 10 are sealed using the sealing spacer 5, and the edges of the substrate 10 and the mold substrate 190 which are opposite to each other are joined to each other with the sealing spacer 5 to form a predetermined cell. (ST 120 step). At this time, the edge portion is left without sealing with the sealing spacer 5 so that the material forming the light diffusion layer can be injected.

The sealing spacer 5 serves to block the external environment while keeping the composition for the diffusion medium to maintain a constant thickness between the substrates. As the sealing spacer 5, a double-sided tape having a constant thickness may be used, or any one selected from polyvinyl butyral, epoxy resin, acrylic resin, isobutylene, silicone, and poly sulfide may be used.

A water-soluble high molecular material that dissolves in water to form a transparent solution, a photocurable hydrophilic monomer having high hydrophilicity and high dispersibility in water, and a photoinitiator and a solvent which react with a photocurable hydrophilic monomer to cause a polymer reaction at a predetermined ratio, thereby spreading the mixture After the composition is produced, the composition for diffusion medium is injected into the formed predetermined cell and the cell is completely sealed (ST 130).

That is, the composition for the diffusion medium is surrounded by a pair of substrates consisting of the substrate 10 and the mold substrate 190, and specifically, the composition for the diffusion medium is a pair of the substrate and the sealing spacer 5 It is filled in the cell made and sealed. At this time, at least one portion of the substrate 10 and the mold substrate 190 is transparent so that the inside thereof is visible. The gap between the mold substrate 190 and the substrate 10 in which the composition for the diffusion medium is filled is not limited, and is formed to be 0.1 to 5.0 mm, preferably 0.1 to 3 mm. If the distance between the mold substrate 190 and the substrate 10 is 0.1mm or less, the thickness of the light diffusion layer is too thin, so that the light diffusion effect is insufficient. If the thickness is 5.0mm or more, the composition for the diffusion medium requires an excessive amount of diffusion medium. Will increase.

The composition for diffusion medium injected into a predetermined cell is exposed to ultraviolet rays, an electron beam, or visible light for a predetermined time to be photocured to form a light diffusion layer 40 (step ST 140). The cured light diffusing layer 40 is removed from the mold substrate 190 and the sealing spacer 5 to complete the projection screen composed of the substrate 10 and the light diffusing layer 40 (step ST 140).

Glass, plastic, ceramic, and metal may be used as the material of the substrate 10. Specifically, in the case of using glass, various forms such as general transparent glass, translucent glass, etched glass, colored glass, tempered glass, laminated glass, wired glass, heat absorbing glass, reflective glass, ultraviolet absorbing glass, metal coated glass, or mirror glass Glass can be used. In addition, when plastic is used, polyethylene (PE) and polypropylene (as well as transparent or translucent poly methyl methacrylate, polycarbonate, and amorphous PET, A-PET) are used. PP), polyester and polyethylene terephthalate (PET), vinyl chloride (PVC), transparent films such as polyurethane, heat shielding film, UV protection film, metal coated film, Saran film It can be used without limitation, such as a special film such as made by Dow Product or Aclar film made by Allied Product.

In addition, the substrate 10 may be formed in a multilayer of one or more layers. That is, several layers of substrates can be used in overlap or functional surface treatments can be applied to the outer surface of the substrate. Functional surface treatments include non-glare treatments to prevent glare from ambient lighting and sunlight, anti-reflection treatments to prevent light reflections from illumination and sunlight, and generation of static electricity. Anti-static treatment to remove, prism treatment to enhance brightness and selective absorption treatment to selectively absorb specific wavelengths. In addition, the surface treatment method may be a method of applying the functional coatings (functional coatings) to the surface or attaching functional films (functional films) using an adhesive.

The composition for transparent or translucent diffusion media according to the present invention comprises at least one water-soluble polymeric material selected, at least one light curable hydrophilic monomer selected, a solvent and a photoinitiator. As a medium that can be obtained through light cure, the composition is transparent or translucent and uniformly diffuses the projection image to form a light diffusion layer 40 for realizing the image.

The solvent used in the composition for the diffusion medium is selectively used among purified water, organic solvent or a mixture thereof. The solvent is to be 0.5 to 35% by weight, preferably 1 to 33% by weight, based on the total weight of the diffusion medium. If less than 0.5% by weight or more than 35% by weight of solvent is used, the diffusion properties of the diffusion medium will be insufficient.

In addition, the water-soluble high molecular material used in the composition for the diffusion medium is selected and used to be dissolved in water to be a transparent solution. Examples of such water-soluble high molecular materials include poly N-isopropyl acrylamide and derivatives thereof, and polymethylvinyl ether and derivatives thereof. The water-soluble high molecular material is made to be 0.5 to 35% by weight, preferably 1 to 33% by weight based on the total weight of the diffusion medium. If less than 0.5% by weight or more than 35% by weight of water-soluble polymer materials are used, the diffusion properties of the diffusion medium also become insufficient.

Since the photocurable hydrophilic monomer used in the composition for the diffusion medium should be easily dispersed in water and maintained in a transparent state so as not to affect the transparent aqueous solution of the water-soluble polymer material, the monomer having high hydrophilicity is preferred and high in dispersibility in water. Do. Photocurable hydrophilic monomers can be selected hydrophilic monomers which are dispersible in water and undergo a polymer reaction by an initiator, for example, hydroxyalkyl esters of unsaturated carboxylic acids, ie hydroxyethyl acrylate. ), Hydroxyethyl methacrylate (hydroxyethyl methacrylate), hydroxypropyl acrylate (hydroxypropyl acrylate), hydroxypropyl methacrylate (hydroxypropyl methacrylate), hydroxybutyl acrylate, hydroxybutyl methacrylate (hydroxybutyl methacrylate) and dimethyl acrylamide, and at least one of them may be selected and used. The photocurable hydrophilic monomer is to be 31 to 98.5% by weight, preferably 33 to 97.5% by weight, based on the total weight of the diffusion medium. If less than 31 wt% or more than 98.5 wt% is used, the diffusion properties of the diffusion medium will also be degraded.

On the other hand, the photoinitiator used in the composition for the diffusion medium may be any photoinitiator that can react with the photocurable hydrophilic monomer to cause a polymer reaction. Examples of such photoinitiators include benzophenone, Ethyl4- (dimethylamino) benzoate, benzyl dimethyl ketal, 1- (4- (2-hydroxyethoxy) -phenyl) -2-hydroxy-2 -Methyl-1-propane-1-one (1- (4- (2-hydroxyethoxy) -phenyl) -2-hydroxy-2-methyl-1-propane-1-one), 2-hydroxy-2-methyl 2-phenyl-2-propane-1-one, trimethyl benzoyl diphenyl phosphine oxide (2,4,6-Trimethyl benzoyl diphenyl phosphine oxide) , Bisacrylphosphine oxide (bisacylphosphine oxide) and the like, optionally one or more of these may be used. The concentration of the photoinitiator is generally about 0.1 to 5% by weight, preferably 0.2 to 4% by weight, for each monomer that can be polymerized.

At least one water-soluble polymer material, a solvent, at least one photocurable hydrophilic monomer, and a photoinitiator are uniformly mixed to irradiate ultraviolet or electron beams to cause a polymer reaction, thereby maintaining a transparent or translucent state at room temperature. In addition, a polymer material for diffusing the projection light, that is, a transmission type diffusion medium is formed.

Meanwhile, a filler may be additionally used in the composition for the diffusion medium according to the present invention, and the filler serves to reduce the volume reduction during the polymerization reaction. The filler according to the present invention can be used without limitation, ultrafine particles, that is, metal or metal oxides having a size capable of passing visible light as nanometer or micron sized particles, for example, gold, copper, alumina, iron oxide, Ultrafine particles such as carbon black and silica may optionally be used. These ultrafine particles are preferably used in the form of a sol dispersed in a solvent. The concentration of the filler according to the present invention is preferably 0.1 to 10% by weight based on the total weight of the monomers.

In addition, a promoter for improving the properties of the composition for the diffusion medium, that is, adhesion to the substrate may be additionally used, for example, 3-glycidoxypropyl dimethyl ethoxysilane. ), 3-glycidoxypropyl methyl diethoxysilane, 3-glycidoxypropyl trimethoxysilane, aminoethylaminopropyl trimethoxysilane, 3 -Methacryloxypropyl trimethoxysilane, bis hydroxyethyl methacrylate phosphate, methoxy polyethylene glycol (meth) acrylate, and the like. When a substrate such as metal or glass is used in a transmissive screen, these groups react with the substrate by functional groups such as phosphate, methoxy, ethoxy and glydoxy to improve adhesion. It is understood to make. The enhancer according to the invention is preferably from 0.1 to 25% by weight, based on the weight of the total monomers. If less than 0.1% by weight is used does not significantly affect the adhesion, if more than 25% by weight is used to affect the heat-sensitive polymer and monomer affects the dispersion properties.

Various additives may be additionally used in the composition for the diffusion medium according to the present invention. Pigments such as pigments or dyes, which can be dispersed uniformly in water or monomers, for example, can be added for the purpose of giving a color effect to the transmissive transmissive screen or for absorbing external light to improve contrast, and also to deteriorate the properties of the monomers. Antioxidants and / or ultraviolet absorbers may additionally be used to reduce them, which should be dispersible in water or monomer and the amount added is preferably 0.01 to 5% by weight relative to the diffusion medium.

In addition, when the composition for the diffusion medium contains water, it may freeze when used at sub-zero temperatures as well as the temperature of the image can be added an organic solvent to prevent this. As the organic solvent, alcohol water of the diffusion medium according to the present invention may be used by using at least one selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, 2-butanol, ethylene glycol, diethylene glycol, and propylene glycol. alcoholic water). These organic materials not only prevent freezing but also serve to improve the dispersibility or stability of some diffusion media. The amount of the organic solvent added varies depending on the function such as preventing freezing or improving dispersibility, or depending on the concentration of the diffusion medium, the mutual affinity and the respective characteristics, but the amount of the organic solvent is 0.01 to 70% by weight relative to the water in the diffusion medium. Be sure to

7 is a cross-sectional view of a rear projection screen of one embodiment according to the present invention. FIG. 7 is an embodiment of a projection screen further comprising a light diffusing film 500 consisting of a light transmitting layer 210 and a second light diffusing layer 150 on top of the light diffusing layer 40 of the projection screen shown in FIG. 4. to be. After manufacturing the screen shown in FIG. 4, one surface of the light diffusion layer 40 includes a light diffusion film 500 composed of a second diffusion layer 150 and a light transmission layer 210 manufactured by coextrusion or coating. It is prepared by lamination. In the example of FIG. 7, the light diffusion film 500 is adhesively formed after applying the adhesive layer 90 on the light diffusion layer 40. The thickness of the light diffusion film 500 is preferably 10 μm to 300 μm. The average particle diameter of the light diffusing agent added during the production of the diffusion film is preferably 0.5 μm to 50 μm. If the average particle size is 0.5μm or less, the light diffusion effect is insufficient, and if the average particle size is 50μm or more, the resolution of the image is reduced.

Although the light diffusing film 500 is integrated with one layer in appearance, the second light diffusing layer 150 is a semi-transparent layer in which one side of the film is spherical and the fine light diffusing agent 30 is evenly dispersed. ) And the light transmitting layer 210 which is a transparent layer which does not contain the light diffusing agent 30 are integrated.

The light diffusing film 500 simultaneously extrudes a translucent molten resin obtained by uniformly dispersing the fine particle diffusing agent 30 in the transparent resin and a transparent molten resin without adding the light diffusing agent 30 in an extrusion mold such as a T-die. It is formed using a coextrusion process made of one film. Alternatively, the light diffusion film 500 is a printing process such as gravure printing or silk screen printing a semi-transparent resin coating liquid in which the fine light diffusing agent 30 is uniformly dispersed in a transparent resin solution on one surface of the light transmitting layer 210. Alternatively, the second light diffusing layer 150 may be formed by a coating method such as roll coating, doctor blade coating, Ti-die coating, and curtain coating.

8 is a cross-sectional view of a front projection or bidirectional screen of one embodiment according to the present invention. The projection screen of the embodiment shown in FIG. 8 has a light reflection layer 140 on one surface of the substrate 10, i.e., in a portion using a metal sheet, a metal coated glass or a metal coated film as the substrate 10. FIG. There is a difference in configuration from the projection screen of the embodiment shown in FIG. Although the light reflection layer 140 is illustrated as being provided between the substrate 10 and the light diffusion layer 40 in the drawing, the light reflection layer 140 may be provided on any side of the substrate 10. Therefore, in the process diagram of FIG. 6, the process of FIG. 8 is added by adding a process of forming the light reflection layer 140 on one surface of the substrate 10 before the step ST120 or by using the substrate 10 on which the light reflection layer 140 is already formed. The screen can be formed.

The light reflective layer serves to increase the brightness of the screen by reflecting the projection light.

The projection screen of FIG. 8 may be used as a front projection screen or a bidirectional (or holographic bidirectional) screen depending on the degree of transmittance and reflectance of the light reflection layer 140. For example, when the light reflection layer 140 has a very low transmittance of 10% or less and a reflectance of 50% or more, it may be used as a front projection screen, and may have a transmittance of 20% or more and a reflectance of about 20% to 60%. Can be used as a double-sided projection screen.

The light reflection layer 140 is a metal foil or sheet of metal such as aluminum, copper, silver or stainless steel, or polyethylene (PE), polypropylene (PP), polyester and polyethylene terephthalate (PET). A metal coating film coated with a thin film of a metal material such as aluminum, copper, nickel, gold, silver, or stainless steel may be used as the transparent film of the material, and the thickness of the metal foil or the metal sheet or the metal coating film may be 10 μm to 0.5. mm is preferred. When using a metal foil or a metal sheet or a metal coating film when the thickness is less than 10μm is easily torn or damaged during handling, if more than 0.5mm the cost is too high. In the structure shown in FIG. 8, the thickness of the light reflection layer 140 is preferably 0.05 μm to 5 μm. When the thickness of the light reflection layer 140 is 0.05 μm or less, a sufficient reflection effect may not be obtained and may be 5 μm or more, but the cost is excessively increased.

9 is a cross-sectional view of a front projection or bidirectional screen of one embodiment according to the present invention. The projection screen of the embodiment shown in FIG. 9 is shown in FIG. 7 in a portion having a substrate 10 having a light reflection layer 140 on one surface of the substrate 10 using a metal coated glass or a metal coated film. There is a difference in configuration from the projection screen of the illustrated embodiment. The manufacturing method and function of the light reflection layer 140 are the same as those of the light reflection layer 140 of FIG. 8.

As shown in the right detailed partial sectional view of FIG. 9, the second light diffusing layer 150, which is a translucent layer including the light diffusing agent 30, has a part of the fine light diffusing agent 30 exposed on one surface thereof to the outside of the film. As a result, it has a surface structure having many similar convex portions, so that diffusion, reflection and scattering occur on the surface and diffusion and transmission inside. The light transmitting layer 210, which does not include the light diffusing agent 30, has only light transmission, so that the projected projection light from the optical engine is applied to other layers on the rear surface, that is, the light reflecting layer 140, the light diffusing layer 40 and The adhesive layer 90 is reached. As for the thickness of the adhesive or adhesive bond layer 90, 0.5 micrometer-50 micrometers are suitable. When the thickness of the pressure-sensitive adhesive or adhesive layer 90 is 0.5μm or less, sufficient adhesion or adhesive effect may not be obtained, and may be 50μm or more, but excessive thickness may degrade the image quality or increase the cost.

10 is a cross-sectional view of a front projection or bidirectional screen of one embodiment according to the present invention. The projection screen shown in FIG. 10 is different from the screen of FIG. 9 in that the second light absorption layer 170 is provided on the outer surface of the second light diffusion layer 150. The second light absorbing layer 170 may be formed using a coating method or a printing method such as roll coating, doctor blade coating, Ti die coating, and curtain coating using achromatic dyes and / or pigments. The second light absorbing layer 170 may also be provided on the outer surface of the light diffusing layer 40 of FIG. 4.

11 is a cross-sectional view of a front projection or bidirectional screen of one embodiment according to the present invention. 11 shows that (1) the light reflection layer 140 is adhered or adhered to the substrate 10 using the adhesive layer or the adhesive layer 90, and (2) the light transmission layer 210 and the light. There is a difference in configuration from the screen of FIG. 10 in that the light absorption layer 160 is provided between the diffusion layers 40. The light absorption layer 160 prints or coats a predetermined pattern, that is, a pattern such as a horizontal or vertical stripe structure, a network structure and a lattice structure, using achromatic dyes and / or pigments on the inner surface of the light transmitting layer 210. Form using the law.

The line thickness of the achromatic pattern of the stripe or the network structure is preferably 1 μm to 0.8 mm, the line thickness is similar to or slightly larger than the line width, the spacing between the lines is preferably 50% to 90% of the total opening of the pattern. Background coating, which does not require a pattern, is preferably evenly coated so that no stain or pinhole occurs in the entire area.

The light absorbing layer and the second light absorbing layer also absorb absorption of the projected light from the optical engine. However, when the light absorbing layer is projected so that the angle between the light absorbing layer and the surface normal is small, the absorption of the light absorbing layer is short because the length of the traveling light path in the light absorbing layer is short. On the other hand, since the incident light from the surrounding environment has a large angle with the normal line and a long running light path in the light absorbing layer, absorption is remarkably increased and contrast is increased while the luminance loss of the image is small.

The thickness of the light absorption layer 160 is appropriately 0.5 μm to 40 μm, and in the screen of the embodiment of FIG. 11, the light reflection layer 140 preferably has a thickness of 10 μm to 0.5 mm. The pressure-sensitive adhesive layer or the adhesive layer 90 may be formed in a light absorption type by adding achromatic dyes and / or pigments.

When the thickness of the light absorbing layer 160 is 0.5 μm or less, a sufficient light absorption effect is not obtained. When the thickness of the light absorbing layer 160 is 40 μm or more, the external light as well as light from the optical engine is excessively absorbed to reduce the brightness of the image. The light reflection layer 140 of the embodiment of Figure 11 is a case of using a metal foil or a metal sheet or a metal coating film of the thickness range of 10μm to 0.5mm as described above in the embodiment of Figure 8, the thickness of the pure light reflection layer, That is, in the case of a pure light reflection layer in the form of a metal coating coated on the surface of a film or glass, the thickness is 0.05 μm to 5 μm. When the thickness of the light reflection layer 140 is 0.05 μm or less, a sufficient reflection effect may not be obtained. It may be okay, but the cost will be too high. However, in the case of a metal foil or a metal sheet, since the light reflection layer 140 is itself, the thickness of the light reflection layer is 10 μm to 0.5 mm.

The light absorbing layer 160 and the second light absorbing layer 170 absorb external light to increase contrast of an image.

12 is a cross-sectional view of a front projection or bidirectional screen of one embodiment according to the present invention. The screen of FIG. 12 has a configuration in which a substrate 10, a light reflection layer 140, an embossing layer 180, a light absorption layer 160, a light diffusion film 500, and a second light absorption layer 170 are sequentially stacked. Each component part is laminated | stacked using adhesive or an adhesive agent. The manufacturing process of the screen of the embodiment shown in FIG. 12 will be briefly described with reference to FIG. 13. The light reflection layer 140 is laminated on the substrate 10 using an adhesive or an adhesive layer 90 (step ST200 and step ST210). The embossing layer 180 is laminated using the adhesive or the adhesive layer 90 on the light reflection layer 140 (step ST220). After forming the light absorption layer 160 on the embossing layer 180 (step ST230), and formed on the light absorption layer 160 on the light diffusion film 500 manufactured by a separate process (ST240 step), the second The light absorbing layer 170 may be formed (step ST250), or the second light absorbing layer 170 may be formed first, and then the light absorbing layer 160 may be formed later. The embossing layer 180 is made by etching or rolling a transparent film such as polyethylene (PE), polypropylene (PP), polyester (polyester) and polyethylene terephthalate (PET), vinyl chloride (PVC) and polyurethane. Embossing film can be used, and the thickness of the embossing film is 10 μm to 150 μm, and it functions to reduce hot spot phenomenon and increase diffusivity easily occurring in high gain screen. . If the thickness of the embossing film is less than 10 μm, it is not enough to reduce the hot spot phenomenon or increase the diffusivity. If the thickness of the embossing film is 150 μm, the hot spot phenomenon is reduced or the diffusivity is further increased, but the image quality is reduced. . The embossed layer refers to a surface of a kind of irregularities in which irregular concavities and convexities raised above the surface are arranged regularly or irregularly, as shown in FIG. 18, and any type of irregularities may be used. 2 Convex portion formed on the surface of the light diffusing layer refers to a structure in which one part of the spherical light diffusing agent rises above the surface and the convex portions in the shape of hemispherical or rod are arranged on the flat surface as shown in FIG. 17. .

14 is a cross-sectional view of a front projection or bidirectional screen of one embodiment according to the present invention. The projection screen shown in FIG. 14 is characterized in that the projection screen shown in FIG. 12 further includes an achromatic additional substrate 11 outside the substrate 10 for contrast enhancement. That is, in the embodiment of FIG. 14, the achromatic additional substrate 11 has the diffusion film 500 in the same manner as the light absorption layer 160 and the second light absorption layer 170 absorb external light in the direction of the diffusion film 500. By absorbing external light in the direction of the achromatic substrate 11 as well as in the) direction, the function further improves the contrast.

An embodiment of manufacturing a front projection screen, a rear projection screen, and a bidirectional screen according to the present invention will be described below.

Example  1 (rear projection screen)

188.9 parts by weight of polymethylvinyl ether as a water-soluble polymer material, 555.8 parts by weight of hydroxyethyl acrylate as a photocurable hydrophilic monomer, 24 parts by weight of trimethyl benzoyl diphenyl phosphine oxide as a photoinitiator, and 211.1 parts by weight of pure water. Prepare. Next, a mold substrate having 4 mm thickness and 30 cm2 clear glass (88.6% visible light transmittance) and 4 mm thickness and 30 cm2 acrylic with a prism structure having a pitch spacing of 0.1 mm and a pitch height of 0.2 mm with a precision cutting machine. To produce a cell by sealing the edge of the substrate with a sealing spacer of 1.6 mm in thickness, injecting the composition prepared in the inner space of the cell, and then sealing the injection hole with silicon. The sealed cell was cured by being exposed to a 200W ultraviolet lamp for about 50 minutes, and then the acrylic mold substrate and the sealing spacer were detached as shown in FIG. 5 to prepare a projection screen.

The projection screen manufactured as described above has a high-definition and high-brightness image on the front of the screen when the beam projector is projected in the vicinity of the rear lower 30 degrees inclination angle under an environment of about 50 lux of indoor illumination, and has a viewing angle of approximately 180 °. Indicated.

Example  2 (bidirectional screen)

6 mm thick and 30 cm2 reflective glass (50% visible light transmittance, 26% reflectance), acrylic with 4 mm thickness and 30 cm2 surface etched, 0.5 mm thick sealing spacer Is sealed to make a cell, and the injection hole is sealed with silicone after injecting the composition as in Example 1 to the inner space of the cell. The sealed cell was cured by being exposed to a 200W ultraviolet lamp for about 50 minutes, and then the acrylic mold substrate and the sealing spacer were detached to prepare a projection screen as shown in FIG. 5. In a separate process, semi-transparent resin in which PMMA particles having an average particle diameter of about 30 μm is uniformly dispersed in a transparent resin solution is coated on a light transmitting layer made of a PET film having a thickness of 150 μm so as to form a screen as shown in FIG. 7. The light-diffusion film was laminated to the prepared projection screen using an adhesive containing an achromatic pigment.

The projection screen manufactured as described above has the effect of displaying high-definition and high-brightness images on the front of the screen and simultaneously displaying high-brightness and high-definition images on the rear side when the beam projector is illuminated from the rear under an environment of about 50 lux indoor illumination. Could get

Example  3 (front projection screen)

Laminate a 100 μm thick and 30 cm ² PET film coated with aluminum using a pressure-sensitive adhesive on one surface of a 3 mm thick, 30 cm ² black opaque acrylic sheet using a pressure-sensitive adhesive, followed by a 100 μm thick and 30 cm ² A substrate prepared by laminating an PVC embossed film with an adhesive and a sheet of transparent polycarbonate (85% visible light transmittance) of 5 mm thickness and 30 cm2 were sealed with a 0.5 mm thick spacer and sealant to seal the edge of the glass plate. It is made into a cell, the composition of Example 1 is injected into the inner space of the cell, and then the inlet is sealed with silicone. The sealed cell was cured by exposure to a 200W ultraviolet fluorescent lamp for about 50 minutes, and then a transparent polycarbonate, that is, a mold substrate and a sealing spacer was detached to prepare a projection screen. In addition, in a separate process, a coextruded light-diffusion film obtained by uniformly dispersing silica particles having an average particle diameter of about 10 μm was laminated on the projection screen prepared by using a pressure-sensitive adhesive containing an achromatic pigment.

When the front projection screen manufactured as described above has a high brightness and high definition image in front of the screen when the beam projector is illuminated from the front under an environment of approximately 50 lux of indoor illumination, a viewing angle of about 170 degrees can be obtained.

Example  4 (transparent Holographic  screen)

4 mm thick and 30 cm2 of clear glass (88.6% visible light transmittance), and 4 mm thick and 30 cm2 of smooth surface acrylic, were made into cells by sealing the substrate edges with a sealing spacer of 1.6 mm thickness. The main inlet is sealed with silicone after injecting the composition of Example 1 into the interior space. The sealed cell was cured by exposure to a 200W ultraviolet fluorescent lamp for about 50 minutes, and then acrylic, that is, a mold substrate and a sealing spacer were detached to prepare a projection screen.

The projection screen manufactured as described above is a transparent holographic screen having a slight haze under an environment of approximately 150 lux of indoor illumination, and has a high definition and high brightness at the front of the screen when the beam projector is projected near the rear lower 30 degrees inclination angle. The image was implemented and the object behind the screen was visible, exhibiting a nearly 180 ° viewing angle.

15 and 16 show an example of an image projection system in which a screen manufactured according to the present invention is applied, and a rear projection screen in which one surface of the light diffusing layer 40 has a prism structure is applied. In particular, it shows an embodiment applied to the screen of the projection TV and the projection monitor that the projection distance is reduced by the rear projection screen of the prism structure. An image projection process of the projection TV and the projection monitor to which the rear projection screen is applied will now be described with reference to FIGS. 15 and 16.

First, an image is implemented in an optical engine 3 composed of a cathode ray tube (CRT), a liquid crystal (LCD), or a digital micro mirror device (DMD) chip with respect to an image signal transmitted from a circuit board 6. The image implemented in the optical engine 3 is projected onto the reflection mirror 2 through the lens unit 4.

The image reflected by the reflection mirror (2) is projected to the rear of the screen (1), since the rear projection screen is projected image is transmitted through the screen (1) to implement the image from the front.

FIG. 17 is an electron micrograph of the surface of a light diffusing film having a plurality of convex portions on one outer surface while at the same time having a second light diffusing layer applied to a projection screen according to the present invention, ie, a fine light diffusing agent.

It should be noted that the projection screen according to the present invention does not have a structure limited to the embodiment shown in the drawings. For example, a second light absorbing layer may be provided on the light diffusing layer 40 of the projection screen shown in FIG. 4, or a light absorbing layer may be provided on the light diffusing layer 40, or embossed on the light diffusing layer 40. Layer 180 may be provided. That is, the light reflection layer 140, the second light absorption layer 170, the light absorption layer 160, the embossing layer 180, and the diffusion film 500 are components that can be selectively added or removed regardless of the order. .

As described above, the projection screen according to the present invention can implement various types of screens such as front projection type, rear projection type, transparent holographic and two-way screen, and can be manufactured at a relatively low manufacturing cost.

In other words, the projection screen according to the present invention,

First, when a screen having a light diffusion layer is manufactured by using a mold substrate having a selected surface structure such as a smooth surface, a prism surface, an uneven surface, and a plurality of convex portions and a composition for diffusion medium, the projection distance may be changed or a hot spot phenomenon may occur. Can be reduced or a transparent or translucent screen can be implemented,

Second, by selectively adding a light reflection layer having various light transmittances and light reflectances, various types of screens such as a front projection type, a rear projection type (including holographic), and a bidirectional screen can be realized using only one type of diffusion medium.

Third, the addition of a second light diffusing layer, optionally with a plurality of convex portions, can further increase the optical viewing angle,

Fourthly, the optional addition of a light absorbing layer can improve contrast,

Fifthly, adding an optional embossing layer can reduce hot spots on the screen,

Finally, it can be applied not only to projection screens but also to a variety of applications such as glass doors, office partitions, aesthetic design such as show windows and advertising fields, so that the application is wide.

While the preferred embodiments of the present invention have been described using specific terms, such descriptions are for illustrative purposes only, and it is understood that various changes and modifications may be made without departing from the spirit and scope of the following claims. Should be done. For example, when the substrate of the manufactured screen is made of a flexible material, it may be implemented as a projection screen by unfolding as needed while storing in a roll form, or by making the frame of the screen to have a curvature in the horizontal or vertical direction, constant curvature The flexible screen on the frame with the same curvature as the frame can be implemented as a curved screen when mounted.

Claims (15)

A projection screen having a substrate and a light diffusion layer attached to one surface of the substrate to diffuse the image evenly, wherein the light diffusion layer is formed through light curing of the composition for the diffusion medium, the composition for the diffusion medium , A water-soluble polymer material that is dissolved in water to form a transparent solution and is 0.5 to 35% by weight based on the total weight; Photocurable hydrophilic monomers which are hydrophilic and have high dispersibility in water and are 31 to 98.5 wt% based on the total weight; A photoinitiator which acts with the photocurable hydrophilic monomer to cause a polymer reaction, and is 0.1 to 5 wt% based on the total weight of the photocurable hydrophilic monomer, and Projection screen, characterized in that the composition comprising a solvent of 0.5 to 35% by weight based on the total weight. The method of claim 1, And a surface of an opposing surface of the light diffusing layer, which is not attached to the substrate, has a surface structure selected from a smooth surface, a prism surface, an uneven surface, and a plurality of convex portions. The method of claim 1, A projection screen further comprising a diffuser film having a second light diffusion layer having a plurality of convex shapes on an outer surface on the light diffusion layer. The method of claim 3, wherein The diffusion film is A projection screen, characterized in that provided with a light transmitting layer and a second light diffusing layer manufactured through a coextrusion process on the light transmitting layer. The method of claim 3, wherein The diffusion film is Projection screen, characterized in that provided with a light transmitting layer and a second light diffusing layer manufactured by a coating process on the light transmitting layer. The method according to claim 3 to 5, The second light diffusing layer has an average particle diameter of 0.5 μm to 50 μm, and a light diffusing agent formed of at least one material selected from silica particles, titanium oxide particles, acrylic resin fine particles, styrene resin fine particles and carbonate resin fine particles is evenly dispersed. A projection screen, characterized in that The method of claim 1, And a light reflection layer having a visible light reflectance of 13% to 95% and a visible light transmittance of 0% to 70% on one surface of the substrate. The method of claim 1, And at least one light absorbing layer is selectively added to the incident surface side of the projected light of the screen using achromatic dyes and / or pigments as light absorbing means. The method of claim 1, Projection screen, characterized in that the outer surface of the light diffusion layer is further provided with at least one light absorbing layer formed of one selected from achromatic dyes and pigments. The method of claim 3, wherein Projection screen, characterized in that the outer surface of the light diffusion film is further provided with at least one light absorbing layer formed of one selected from achromatic dyes and pigments. The method of claim 1, Projection screen, characterized in that the embossing film is further provided on the light diffusion layer. The method of claim 3, wherein Projection screen, characterized in that the embossing film is further provided between the light diffusion layer and the diffusion film. Substrate, A light reflection layer provided on the substrate and having a reflectance of 13% to 95% with respect to incident visible light and having a transmittance of 70% or less; A light absorbing layer provided on the light reflecting layer, the light absorbing layer absorbing visible light incident by being formed in a predetermined pattern using at least one material selected from achromatic dyes or pigments; It is provided on the light absorbing layer, characterized in that it comprises a diffusion film formed of a light transmitting layer and a second light diffusion layer, The second light diffusing layer has an average particle diameter of 0.5 μm to 50 μm, and the light diffusing agent formed of at least one material selected from silica particles, titanium dioxide particles, acrylic resin fine particles, styrene resin fine particles and carbonate resin fine particles is evenly dispersed. Featuring projection screen. The method of claim 13, A projection screen further comprising an embossing film between the light reflection layer and the diffusion film. An image projection system comprising the projection screen of claim 1.

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