KR100945753B1 - Projection type screen - Google Patents

Abstract

The present invention relates to a projection screen, comprising: a light transmissive substrate; And a colored binder resin layer containing a colorant and two or more kinds of beads having different average particle diameters and refractive indices on one or both sides of the substrate, wherein the projection-type screen of the present invention is viewed from the front of the viewer side. This is invisible, has a high brightness and has the effect of greatly improving the viewing angle.

Description

Projection Screen {PROJECTION TYPE 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.

<Brief description of symbols used in the drawings>

11: screen 12: mirror

13: projector 21: first bead

22: second bead 23, 25: colored binder resin layer

24: base material 26: protective film

27 adhesion layer 28 release film (transparent substrate)

The present invention relates to a projection screen, and more particularly to a projection 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), An image display system in which an image is generated by using an image display means such as a digital lighting processing (DLP) display, and the image is reflected on the screen 11 directly or by reflecting the image directly to the mirror 12. The demand is increasing day by day from the advantage of obtaining a large screen to meet the needs of consumers.

Such image projection systems include a front projection system called a front type 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 light-transparent beads partially embedded in the light transparent layer.                         

However, the screen according to the prior art as described above has a problem in that it does not secure sufficient desired brightness or viewing angle, and has a disadvantage in that a 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 beads, or a separate Fresnel lens is disposed. There is a problem that the degradation, the complexity of the process and the cost increase due to the arrangement of the lens.

Accordingly, an object of the present invention is to provide a projection type screen in which the light source of the projector is not seen when viewed from the front of the viewer, and the luminance is high, and the viewing angle is greatly improved, and a projection type system using the same. .

In order to achieve the above technical problem, the present invention is a light-transmissive substrate; And a colored binder resin layer containing on one or both sides of the substrate a colorant and two or more kinds of beads having different average particle diameters and refractive indices.

In order to achieve the above another technical problem, the present invention provides a front or rear projection type system, which includes magnifying and projecting an image generated by an image generating apparatus on the projection type screen.                     

Hereinafter, the present invention will be described in more detail.

As illustrated in FIG. 2, a projection screen according to an exemplary embodiment of the present invention may include a binder resin, a curing agent, a coloring agent, and two or more beads 21 having different average particle diameters and refractive indices on one or both surfaces of the substrate 24. , 22) is applied to a composition prepared by dispersing it in a solvent, and is prepared by applying colored light or heat to form the colored binder resin layers 23 and 25. Applying light or heat after applying the binder resin-containing composition causes self curing or curing reaction between the binder resin and the curing agent, and the result of the curing reaction of the binder resin and the curing agent, colorant, and two or more kinds in the final colored binder resin layer. Beads will be present.

The two or more beads used in the present invention have different average particle diameters in the range of 0.1 to 200 μm, preferably 0.1 to 100 μm. If the average particle diameter of the beads exceeds 200 μm, the viewing angle is deteriorated, and if smaller than 0.1 μm, there is a problem of lowering the luminance, 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 diameters. It is preferable that these two or more types of beads have a difference in average particle diameter between each other in a range of 0.01 to 100 m.

In addition, the two or more beads used in the present invention have different refractive indices in the range of 1.30 to 2.50, preferably 1.4 to 1.9. If the refractive index of the bead is less than 1.30, the viewing angle becomes worse, and if it exceeds 2.50, it is not preferable because the luminance is lowered. That is, desired brightness and sufficient viewing angle can be obtained by appropriately mixing and using beads having different refractive indices. These two or more beads preferably have a difference in refractive index between 0.01 and 1.0.

Organic beads, inorganic beads and organic-inorganic mixed beads may all be used as the beads according to the present invention, and as materials thereof, 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 polymethyl methacrylate (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.

In addition, the colorant serves to improve the contrast of the projected image by absorbing the incident external light to reduce the amount of reflection of the external light. Black dyes or pigments are used as the colorant, and examples thereof include carbon black. The colorant may be used in an amount of 1 to 200 parts by weight, preferably 1 to 100 parts by weight, based on 100 parts by weight of the binder resin. If the content of the colorant is less than 1 part by weight, the added effect is insignificant. If the content of the colorant is more than 200 parts by weight, the brightness of the projection screen is decreased, which is not preferable.

As the curing agent according to the present invention, an isocyanate-based curing agent may be used (particularly suitable when the binder resin is two or more core resins), 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 colored binder resin layer on the substrate may be adopted without particular limitation as long as it is a method commonly known in the art. Air knife coating method, gravure coating method, reverse roll coating method, spray coating method and blade roll coating method can be used arbitrarily selected. At this time, 2-100 micrometers is suitable for the thickness of a colored 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.

As the substrate of the present invention, a light-transmitting material such as plastic film such as acrylic, polyester, polycarbonate, polystyrene, glass, glass fiber, ceramic fiber, fiber cloth, synthetic paper is used, and in particular, the image emitted from the lens of the projector In order to increase the beam transmittance and the brightness of the screen, it may be formed of glass, and may be formed of a transparent acrylic plate in order to be 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.

Typically, as illustrated in FIG. 2, after the colored binder resin layers 23 and 25 according to the present invention are formed on one or both surfaces of the base material 24, an acrylic or urethane adhesive or an adhesive is applied 27. Alternatively, the release film (transparent substrate) 28 may be bonded to the substrate 24 or the colored binder resin layer 23 using an adhesive or adhesive tape to complete the projection screen. At this time, the protective film 26 may be positioned on the surface of the colored binder resin layer 25 to which the transparent substrate 28 is not bonded.

According to the present invention, there is provided a front or rear projection 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 apparatus, means such as a cathode ray tube (CRT), a liquid crystal display (LCD), and a DLP type display may be used.

As such, the projection 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 type systems. In addition, according to the bead composition can be adjusted to the desired brightness and viewing angle can be produced a variety of projection screen products.                     

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>

100 weight part of following binder resins, 3 weight part of coloring agents, and 20 weight part of hardening | curing agents were melt | dissolved in the methyl ethyl ketone / toluene / oxytol mixed solvent, 80 weight part of the following three types of beads were added, and it disperse | distributed, stirring. 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 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㎛, refractive index 1.42)

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

           (Weight ratio = 100: 74: 30)

Colorant: Carbon Black

<Example 2>

100 weight part of the following binder resins, 1.5 weight part of coloring agents, and 20 weight part of hardening | curing agents were melt | dissolved in the methyl ethyl ketone / toluene / oxytol mixed solvent, 73.5 weight part of the following three types of beads were added, and it stirred, and was made to disperse | distribute. The composition thus prepared was applied to both surfaces of the substrate and heated to 100 to 150 ° C. to form a colored binder resin layer having a thickness of 12 μm on both surfaces of the substrate.

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

Curing agent: Brunnock DN-950 (manufactured by 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㎛, refractive index 1.42)

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

           (Weight ratio = 100: 74: 30)

Colorant: Carbon Black

<Example 3>

A colored binder resin layer was formed on both sides of the substrate in the same manner as in Example 2, except that three kinds of beads were added at 62 parts by weight.

<Example 4>

A colored binder resin layer was formed on both sides of the substrate in the same manner as in Example 2, except that three kinds of beads were added at 86 parts by weight.

Example 5

A colored binder resin layer was formed on both sides of the substrate in the same manner as in Example 2 except that polymethyl methacrylate beads and melamine formaldehyde beads (two kinds) were used in a weight ratio of 100: 30.

<Example 6>

A colored binder resin layer was formed on both sides of the substrate in the same manner as in Example 2, except that methylsilicone beads and melamine formaldehyde beads (two kinds) were used in a weight ratio of 100: 30.

<Example 7>

Except that calcium carbonate (CaCO ₃ ) beads (average particle diameter 0.6 µm, refractive index 1.6) and silica (SiO ₂ ) beads (average particle diameter 2 µm, refractive index 1.46) (2 types) were used in a weight ratio of 100: 6. The colored binder resin layer was formed on both surfaces of the base material by the method similar to Example 2.

<Example 8>

Except for using polymethyl methacrylate beads, methyl silicon beads and silica (SiO ₂ ) beads (average particle diameter 2.7㎛, refractive index 1.47) (3 types) in a weight ratio of 100: 70: 20, In the same manner, a colored binder resin layer was formed on both sides of the substrate.

Example 9

Polymethyl methacrylate beads, methylsilicone beads, melamine formaldehyde beads and silica (SiO ₂ ) beads (average particle diameter 2.7㎛, refractive index 1.47) (4 types) were used in a weight ratio of 100: 70: 30: 20 Formed the colored binder resin layer on both surfaces of a base material by the method similar to the said Example 2.

<Example 10>

A colored binder resin layer was formed on both sides of the substrate in the same manner as in Example 2, except that polymethylmethacrylate beads and methylsilicon beads (2 types) were used in a weight ratio of 100: 15.

Comparative Example 1

A colored binder resin layer was formed on both sides of the substrate in the same manner as in Example 2 except that only polymethyl methacrylate beads (one kind) was used in an amount of 73.5 parts by weight.

Comparative Example 2

A colored binder resin layer was formed on both sides of the substrate in the same manner as in Example 2, except that only melamine formaldehyde beads (one type) were used in an amount of 73.5 parts by weight.

Comparative Example 3

A colored binder resin layer was formed on both sides of the substrate in the same manner as in Example 2, except that only methyl silicon beads (one type) was used in an amount of 73.5 parts by weight.

<Test Example>

For the projection screens prepared in Examples 1-10 and Comparative Examples 1-3, the 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.

<Measuring luminance and viewing angle>

* Luminometer: BM-7 Luminance Colorimeter (TOPCON)

1. Prepare a light source of constant intensity under dark conditions

2. Place the specimen in front of the prepared light source

3. Place the luminance meter on the front of the specimen

4. Focus

5. Measurement of Normal Brightness in Specimen

6. Measure the position of the luminance meter by angle                     

From Table 1, in the case of the comparative example using a single bead, Comparative Examples 1 and 3 are not only suitable for use as a product because the light source is visible, the viewing angle is greatly reduced, Comparative Example 2 has a very low brightness, while the average particle diameter and refractive index It can be seen that Examples 1 to 10 used by mixing two different kinds of beads, three kinds, and four kinds of beads have excellent brightness and viewing angle, and do not show a light source.

The projection 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, according to the bead composition can be adjusted to the desired brightness and viewing angle can be produced a variety of projection screen products.

Claims (16)

Light transmissive substrates; A colored binder resin layer provided on one side or both sides of the substrate; A release film provided on one surface of the substrate or the colored binder resin layer and bonded by an adhesive layer; And a protective film provided on one surface of the colored binder resin layer not provided with the release film, wherein the colored binder resin layer contains a colorant and at least three beads having different average particle diameters and refractive indices, and the colorant Is contained in an amount of 1 to 100 parts by weight based on 100 parts by weight of the binder resin. The method of claim 1, And wherein said three or more beads have different average particle diameters within the range of 0.1 to 200 μm. The method of claim 2, And wherein said three or more beads have an average particle diameter difference in the range of 0.01 to 100 μm. The method of claim 1, And the three or more beads have different refractive indices in the range of 1.30 to 2.50. The method of claim 4, wherein And wherein said three or more 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 screen, which is characterized by consisting of a material selected from ₂ -containing polymethylmethacrylate. The method of claim 1, A projection screen, wherein 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 screen, wherein the binder resin is an acrylic resin or a urethane resin. The method of claim 1, A projection screen, characterized in that the colorant is carbon black. delete The method of claim 1, A projection screen, wherein the colored binder resin layer contains an isocyanate curing agent. The method of claim 11, A projection 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, The projection-type screen, wherein the colored binder resin layer has a thickness of 2 to 100 µm. The method of claim 1, A projection-type screen, wherein the light transmissive substrate is made of a material selected from acrylic, polyester, polycarbonate, polystyrene, glass, glass fiber, ceramic fiber, fiber cloth, and synthetic paper. A front or rear projection system comprising the projection screen of claim 1 for magnifying and projecting an image generated by an image generating device. The method of claim 15, A front or rear projection 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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