KR20060112818A - Projective White Screen - Google Patents

Abstract

The present invention relates to a projection type white screen, comprising: a light transmissive substrate; And a structure in which a binder resin layer containing two or more kinds of beads having different average particle diameters and refractive indices is laminated on one or both surfaces of the substrate without a colorant component, when viewed from the front of the viewer. The light source of the projector is not visible, and the brightness is high and the viewing angle is greatly improved.

Description

Projection White Screen {PROJECTION TYPE WHITE-COLORED SCREEN}

1 is a diagram illustrating a basic configuration of a rear projection system,

2 is a cross-sectional view of a projection screen in accordance with one embodiment of the present invention,

3 is a cross-sectional view of a projection screen in accordance with another embodiment of the present invention,

4 is a cross-sectional view of a projection screen in accordance with another embodiment of the present invention.

<Brief description of symbols used in the drawings>

11: screen 12: mirror

13: projector 21: first bead

22: second bead 23, 25: binder resin layer

24: base material 26: protective film

27: adhesive layer 28: soft light transmissive film

29: transparent substrate

The present invention relates to a projection white screen, and more particularly to a projection white screen suitable for large front and rear projection display.

Image projection (projection) systems of goods such as projection televisions or video projectors, as shown in FIG. 1, are specially designed small cathode ray tubes (CRTs), liquid crystal displays (LCDs), DLPs, and the like. An image display system in which an image is generated by using an image display means such as a digital lighting processing type display and the image is reflected on the screen 11 directly or by reflecting the image to the mirror 12. Due to the advantage of obtaining a large screen that can meet the needs of the situation is increasing demand day by day.

Such image projection systems include a so-called front projection system and a rear projection system called a rear type according to a method of projecting an image onto a screen as is well known. Light is projected forward along the projection axis toward the image to form an image on the screen surface that is perceived by the observer in front of the screen.

As a conventional projection type screen, as shown in Japanese Patent Laid-Open No. 2-77736, a diffusion panel is placed on a transparent panel, and a spherical lens is adhered thereto by an adhesive resin. In addition, Japanese Patent Laid-Open No. Hei 7-5570 discloses a screen sheet material for which a bead layer including a binder and transparent beads or colored beads is formed on either side of a substrate made of a material having light transparency.

On the other hand, Korean Patent Publication No. 2001-0042275 discloses a screen having a light transparent layer having a predetermined thickness on one side of a substrate, and the light-transparent beads partially embedded in the light transparent layer.

However, the screen according to the prior art as described above has a disadvantage in that the desired lightness or viewing angle is not secured and the light source is visible when the screen is viewed from the viewer side. In order to make the light source invisible, a black dye or pigment is mixed and coated with an adhesive or adhesive for fixing the beads, or a separate Fresnel lens is disposed. However, there is a problem that the process is complicated and the cost is increased due to the arrangement of the lens.

Accordingly, an object of the present invention is to improve the problems of the prior art, the light source of the projector is not visible when viewed from the front of the viewer side, the brightness is high, greatly improving the viewing angle, and can be manufactured into a screen having a variety of brightness and viewing angle projection screen And a projection type imaging system using the same.

In order to achieve the above object, in the present invention, a light-transmissive substrate; And a structure in which a binder resin layer containing two or more kinds of beads having different average particle diameters and refractive indices is laminated on one or both surfaces of the substrate without a colorant component.

In order to achieve the above another object, the present invention provides a projection type white screen comprising a structure in which a light transmitting film that is softer than a substrate is further laminated on the binder resin layer or the substrate surface.

In order to achieve the above another object, the present invention provides a front or rear projection image system, comprising an enlarged projection of the image generated by the image generating apparatus on the projection white screen.

The present invention will be described in more detail below.

As illustrated in FIGS. 2A and 2B, a projection screen according to an embodiment of the present invention may include two or more kinds of binder resins, curing agents, and different average particle diameters and refractive indices on one surface of the substrate 24. The composition prepared by disperse | distributing the beads 21 and 22 in a solvent is apply | coated, and it manufactures by forming a binder resin layer 23 by applying light or heat. The screen thus manufactured may be coated with an adhesive or an adhesive as an acrylic or urethane-based adhesive or adhesive layer 27 on the surface of the binder resin layer 23 (a) or the substrate 24 (b) according to the purpose of use, or the adhesive or adhesive tape may be applied. It can be used to attach to a transparent substrate 29, such as glass, acrylic, polycarbonate, polyethylene, polypropylene, polyvinyl chloride (PVC), or to bond the soft light-transmitting film 28 for durability improvement. In this case, the protective film 26 may be positioned on the opposite side of the surface on which the transparent substrate 29 or the flexible light transmissive film 28 is bonded.

The projection screen according to another embodiment of the present invention is a binder resin, a curing agent, and two or more beads having different average particle diameters and refractive indices on both surfaces of the substrate 24, as illustrated in FIGS. 3A and 3B. It is prepared by applying a composition prepared by dispersing (21, 22) in a solvent and applying light or heat to form the binder resin layers 23, 25. The screen thus prepared may be coated with an adhesive or an adhesive as an acrylic or urethane-based adhesive or adhesive layer 27 on one side (a) or both sides (b) of the binder resin layers 23 and 25 according to the purpose of use, or by applying an adhesive or adhesive tape. It can be used to attach to a transparent substrate 29, such as glass, acrylic, polycarbonate, polyethylene, polypropylene, polyvinyl chloride (PVC), or to bond the soft light-transmitting film 28 for durability improvement. In this case, the protective film 26 may be positioned on the opposite side of the surface on which the transparent substrate 29 or the flexible light transmissive film 28 is bonded.

In the present invention, the binder resin-containing composition is applied to the substrate and then undergoes self curing or curing reaction of the binder resin and the curing agent by light or heat, and the result of the curing reaction of the binder resin and the curing agent in the final binder resin layer and There will be two or more beads.

In this invention, it is preferable to use 2 or more types of beads from which an average particle diameter and refractive index differ from each other. By properly selecting two or more different beads, various luminance and viewing angles can be achieved.

Two or more beads used in the present invention have different average particle diameters in the range from 0.1 to 100 μm, preferably from 0.1 to 50 μm. If the average particle diameter of the beads exceeds 100 μm, the viewing angle is deteriorated, and if smaller than 0.1 μm, there is a problem of lowering the brightness, which is not preferable. According to the present invention, the beads having different average particle diameters are mixed with each other, so that the effect of light diffusion and the viewing angle are widened and the light source is invisible as compared with the presence of only single particle diameter beads. This is because the number of beads per unit area of the substrate can be increased by filling the voids between the beads having the larger particle diameters with the beads having the smaller particle size, and the difference in average particle diameter of these beads is in the range of 0.01 to 99.9 μm, preferably in the range of 0.01 to 20 μm. to be.

In addition, the two or more beads used in the present invention have different refractive indices in the range of 1.3 to 2.5, preferably 1.4 to 1.7. When the refractive index of the bead is less than 1.3, the viewing angle becomes worse, and when it exceeds 2.5, it is not preferable because the luminance is lowered. In other words, by appropriately mixing and using beads having different refractive indices, the desired brightness and sufficient viewing angle can be obtained, and the difference between the refractive indices of these beads is preferably in the range of 0.01 to 1.0.

Organic beads, inorganic beads and organic-inorganic mixed beads may all be used as the beads according to the present invention, and materials thereof include acrylics such as polymethyl methacrylate (PMMA); Silicone based such as methyl silicone and polyorganosiloxane; Melamines such as melamine formaldehyde; Styrenes such as polystyrene and methyl styrene; Acrylic-polystyrene systems such as polymethylmethacrylate (PMMA) -polystyrene (PS); Vinyl type such as divinylbenzene; Calcium carbonate (CaCO ₃ ); Silica (SiO ₂ ); And SiO ₂ -containing polymethylmethacrylate can be used.

The beads may be used in an amount of 5 to 400 parts by weight, preferably 5 to 150 parts by weight, based on 100 parts by weight of the binder resin. When the content of the beads is less than 5 parts by weight, the beads are not evenly applied evenly, and when the content exceeds 400 parts by weight, there is a problem that the viewing angle is reduced or the brightness is reduced, which is not preferable.

In the present invention, as the binder resin, one or more types of transparent resins such as acrylic resins or urethane resins may be used.

As the curing agent according to the present invention, an isocyanate-based curing agent may be used (particularly suitable when the binder resin is a two-component or more resin), and may be used in an amount of 5 to 40 parts by weight based on 100 parts by weight of the binder resin.

In the present invention, a solvent commonly used may be appropriately selected and used as necessary. Examples thereof include water and amines substituted with alcohols, phenols, ethers, aldehydes, ketones, carboxylic acids, and amino groups. Organic solvents are mentioned.

The method of forming the binder resin layer on the substrate may be adopted without particular limitation as long as it is commonly known in the art, and may be, for example, a mayer bar coating method or an air knife according to the material and shape of the substrate. Any of a knife coating method, a gravure coating method, a reverse roll coating method, a spray coating method and a blade roll coating method may be arbitrarily selected. At this time, 2-100 micrometers is suitable for the thickness of a binder resin layer. When the thickness is thinner than 2 μm, it is difficult to fix the beads disposed in the resin layer, and the light source is easy to see, and when the thickness is thicker than 100 μm, the luminance is small, which is not preferable.

The substrate of the present invention has a light transmittance such as polyethylene, polypropylene, polyethylene terephthalate, PVC or PVC-based, polyacryl, polyester, polycarbonate, polystyrene, plastic film, glass, glass fiber, ceramic fiber, fiber cloth, synthetic paper The material may be used, and in particular may be formed of glass to increase the beam transmittance of the image emitted from the lens of the projector and the brightness of the screen, and may be formed of a transparent acrylic plate to make it light in weight and inexpensive. Although the thickness of a base material is not specifically limited, 5-10,000 micrometers is preferable in consideration of said transmittance | permeability, brightness | luminance, a weight, etc.

In the present invention, the flexible light-transmitting film is to improve the durability of the overall screen by reducing the problem of tearing the substrate and the turbidity generated when the projection screen is applied in a roll type, the material is poly Preference is given to vinyl chloride (PVC), polyethylene (PE), polypropylene (PP), tarpaulin (PVC-coated paper) and the like. Such a soft light-transmissive film has a softer property than the substrate used, that is, a property in which the elongation is generally 30% or more and the tensile strength is 500 kg / cm 2 or less as measured by the ASTM D-638 method. Although it is preferable to join by thickness more than micrometer, when the thickness is less than 10 micrometer, durability improvement effect is inadequate. In addition, the film has a light transmittance of 10% or more so as not to lower the physical properties of the screen, and may be used after the treatment such as embossing, hard coating, antiglare, antireflection, etc. as necessary.

According to the present invention, there is provided a front or rear projection imaging system, which includes the projection of the image generated by the image generating apparatus directly or in a mirror to the projection screen of the present invention. As the image generating device, means such as a cathode ray tube (CRT), a liquid crystal display (LCD), and a DLP display can be used.

As such, the projection white screen of the present invention does not see the light source of the projector when viewed from the front of the viewer side, and has a high brightness and an effect of greatly improving the viewing angle, and thus can be efficiently used in various front or rear projection systems. . In addition, it is possible to adjust to the desired brightness and viewing angle according to the bead composition to produce a variety of projection screen products, especially when bonding soft light-transmissive film is excellent as a roll type projection screen product Do.

Hereinafter, the present invention will be described in more detail based on the following Examples and Comparative Examples. However, the following examples are not intended to limit the invention only.

Example 1

After dissolving 100 parts by weight of the binder resin and 20 parts by weight of the curing agent in a methyl ethyl ketone / toluene / oxytol mixed solvent, 80 parts by weight of the following three beads were added and dispersed while stirring. The composition thus prepared was applied to one side of the substrate and heated to 100 to 150 ° C. to form a binder resin layer having a thickness of 12 μm on one side of the substrate.

Binder Resin: Acridict AA-960-50 (Aekyung Chemical Co., Ltd.)

Curing agent: Brunnock DN-950 (Aekyung Chemical Co., Ltd.)

Beads (3 types): polymethyl methacrylate beads (average particle size 5 탆, refractive index 1.49)

            Methylsilicon beads (average particle diameter 2 μm, refractive index 1.42)

            Melamine formaldehyde beads (average particle diameter 2 ㎛, refractive index 1.57)

            (Weight ratio = 100: 74: 30)

Example 2

After dissolving 100 parts by weight of the binder resin and 20 parts by weight of the curing agent in a methyl ethyl ketone / toluene / oxytol mixed solvent, 73.5 parts by weight of the following three beads were added and dispersed while stirring. The composition thus prepared was applied to both surfaces of the substrate and heated to 100 to 150 ° C. to form a binder resin layer having a thickness of 12 μm on both sides of the substrate.

Binder Resin: Acridict AA-960-50 (Aekyung Chemical Co., Ltd.)

Curing agent: Brunnock DN-950 (Aekyung Chemical Co., Ltd.)

Beads (3 types): polymethyl methacrylate beads (average particle size 5 탆, refractive index 1.49)

           Methylsilicon beads (average particle diameter 2 µm, refractive index 1.42)

           Melamine formaldehyde beads (average particle diameter 2 ㎛, refractive index 1.57)

           (Weight ratio = 100: 74: 30)

Example 3

100 weight part of the following binder resins and 20 weight part of hardening | curing agents were melt | dissolved in the methyl ethyl ketone / toluene / oxytol mixed solvent, 61.2 weight part of the following 2 types of beads were added, and it stirred, and was made to disperse | distribute. The composition thus prepared was applied to one side of the substrate, and heated to 100 to 150 ° C. to form a colored binder resin layer having a thickness of 11 to 12 μm on one side of the substrate. Subsequently, 100 weight part of following binder resins and 20 weight part of hardening | curing agents were melt | dissolved in the same solvent, 85.7 weight part of the following three types of beads were added, and it stirred, and stirred. The composition thus prepared was applied to the other side of the substrate and heated to 100 to 150 ° C. to form an uncolored binder resin layer having a thickness of 11 to 12 μm.

[First Binder Resin Layer]

Binder Resin: Acridict AA-960-50 (Aekyung Chemical Co., Ltd.)

Curing agent: Brunnock DN-950 (Aekyung Chemical Co., Ltd.)

Beads (2 types): polymethyl methacrylate beads (average particle size 5 탆, refractive index 1.49)

            Melamine formaldehyde beads (average particle diameter 2 ㎛, refractive index 1.57)

           (Weight ratio = 100: 30)

[2nd binder resin layer]

Binder Resin: Acridict AA-960-50 (Aekyung Chemical Co., Ltd.)

Curing agent: Brunnock DN-950 (Aekyung Chemical Co., Ltd.)

Beads (3 types): polymethyl methacrylate beads (average particle size 5 탆, refractive index 1.49)

           Methylsilicon beads (average particle diameter 2 μm, refractive index 1.42)

           Melamine formaldehyde beads (average particle diameter 2 ㎛, refractive index 1.57)

           (Weight ratio = 100: 74: 30)

Examples 4-6

The projection screens were produced in the same manner as in Examples 1 to 3, except that the soft light-transmissive film was adhered onto the binder resin layer or the first binder resin layer using the following adhesive.

Adhesive: acrylate adhesive

Flexible light transmissive film: PVC film (thickness 40 μm, light transmittance 94%, elongation 80%, tensile strength 200 kg / cm 2)

Comparative Example 1

1.5 parts by weight of a coloring agent was further used in the binder resin composition, and the number of binders on both sides of the substrate was the same as in Example 2, except that only polymethyl methacrylate beads (one type) was used in an amount of 73.5 parts by weight. Formed strata.

Comparative Example 2

A binder resin layer was formed on both sides of the substrate in the same manner as in Comparative Example 1 except that melamine formaldehyde beads (one kind) were used in an amount of 73.5 parts by weight as the beads.

Comparative Example 3

A binder resin layer was formed on both sides of the substrate in the same manner as in Comparative Example 1 except that methylsilicone beads (one kind) were used in an amount of 73.5 parts by weight as the beads.

Test Example

For the projection screens manufactured in Examples 1 to 6 and Comparative Examples 1 to 3, durability, brightness and viewing angle were measured by the following method, and the measured results are shown in Table 1 below with or without light source hiding power.

<Measurement method of durability>

1. Cross hatch test before and after UV irradiation

Using cross hatch test equipment, draw 100 squares at a time by drawing horizontal and longitudinal lines on the surface of the specimen, attaching the nitto tape on it, and pulling the tape off with force. The number of squares attached to the phase was counted and the retention rate (%) of the specimens compared to the initial number of squares was measured.

2. Winding-unwinding repeated test

First, the specimens to be evaluated were cross hatched. Then, cut the center part of the existing roll screen to an arbitrary size (about A4), cut the sample to be evaluated according to the size, fix the empty part with tape, etc., and unwind and wind about 1,000 times. The specimens were cross hatched again. The damage rate (%) of the specimens was calculated by comparing the cross hatch test results before and after the unwinding-rewinding test.

<Measuring luminance>

Prepare a light source with a constant intensity under dark conditions, place the specimen in front of the prepared light source, place a luminance meter (BM-7 Luminance Colorimeter, TOPCON) on the front of the specimen, focus, and then normal Luminance was measured. In addition, the position of the luminance meter was shifted according to the angle, and the change of the luminance value according to the change of the viewing angle was measured (in the case of the luminance, the measured luminance of Example 1 was evaluated based on 100, and there was a slight difference depending on the light source).

In addition, Table 1 shows whether the light source is concealed by observing whether or not the light source of the projector is visible when the projector is projected.

From the above Table 1, in the case of the comparative example using a single bead, Comparative Examples 1 and 3 are poor in durability, not only suitable for use as a product because the light source is visible, but also greatly reduce the viewing angle, especially in the case of Comparative Example 2 Very low; It can be seen that Examples 1 to 6, in which two and three kinds of beads having different average particle diameters and refractive indices were mixed, are excellent in both brightness and viewing angle, and no light source is seen. In particular, it can be seen that Examples 4 to 6 in which the soft film is bonded are excellent in durability and no light source is seen.

The projection white screen of the present invention is not only excellent in durability, but also invisible to the light source of the projector when viewed from the front of the viewer side, and has a high brightness and an effect of greatly improving the viewing angle, so it is efficiently used in various front or rear projection systems. Can be. In addition, it is possible to adjust the desired brightness and viewing angle according to the bead composition can produce a variety of projection screen products. In addition, the soft film can be bonded to improve durability.

Claims (19)

Light transmissive substrates; And a structure in which a binder resin layer including two or more kinds of beads having different average particle diameters and refractive indices is laminated on one or both surfaces of the substrate without containing a colorant component. The method of claim 1, Projective white screen, characterized in that the at least two beads have different average particle diameters within the range of 0.1 to 100 μm. The method of claim 2, A projection white screen, characterized in that the at least two beads have an average particle diameter difference in the range of 0.01 to 20 μm. The method of claim 1, A projected white screen, characterized in that the at least two beads have different refractive indices in the range of 1.30 to 2.50. The method of claim 4, wherein A projected white screen, characterized in that the at least two beads have a refractive index difference in the range of 0.01 to 1.0. The method of claim 1, Beads are polymethylmethacrylate, methylsilicone, polyorganosiloxane, melamine formaldehyde, polystyrene, methylstyrene, polymethylmethacrylate-polystyrene, divinylbenzene, calcium carbonate (CaCO ₃ ), silica (SiO ₂ ) and SiO A projection-type white screen, characterized by consisting of a material selected from _two -containing polymethylmethacrylates. The method of claim 1, Projective white screen, characterized in that the beads are used in an amount of 5 to 400 parts by weight based on 100 parts by weight of the binder resin. The method of claim 1, A projection type white screen, wherein the binder resin is an acrylic resin or a urethane resin. The method of claim 1, A projection type white screen, wherein the binder resin layer contains an isocyanate curing agent. The method of claim 9, A projection white screen, wherein the curing agent is used in an amount of 5 to 40 parts by weight based on 100 parts by weight of the binder resin. The method of claim 1, A projection-type white screen, wherein the binder resin layer has a thickness of 2 to 100 µm. The method of claim 1, Characterized in that the light transmissive substrate is made of a material selected from polyethylene, polypropylene, polyethylene terephthalate, PVC or PVC-based, polyacryl, polyester, polycarbonate, polystyrene, glass, glass fiber, ceramic fiber, fiber cloth, and synthetic paper, Projective White Screen The method of claim 1, The projection type white screen characterized by including the structure which further laminated | stacked the light transmissive film softer than a base material on the binder resin layer or base material surface. The method of claim 13, A projection white screen, wherein the soft, transparent film has a light transmittance of 10% or more, an elongation of 30% or more, and a tensile strength of 500 kg / cm 2 or less. The method of claim 13, A projection white screen, characterized in that the soft, transparent film has a thickness of at least 10 μm. The method of claim 13, A projection white screen, characterized in that the soft, transparent film is made of polyvinylchloride (PVC), polyethylene (PE), polypropylene (PP), tarpaulin. The method of claim 13, A projection white screen, characterized in that the soft, transparent film is embossed, hardcoated, antiglare or antireflective. A front or rear projection imaging system comprising an enlarged projection of an image generated by an image generating apparatus on a projection white screen of claim 1. The method of claim 18, A front or rear projection imaging system, characterized in that the image generating device is a cathode ray tube (CRT), liquid crystal display (LCD) or DLP type display.

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