KR20060092443A - Projection type screen having good durability - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type screen having excellent durability, wherein a binder resin layer containing beads is laminated on one or both surfaces of a light transmissive substrate, and a light transmissive film softer than the substrate is laminated on this binder resin layer or substrate surface. The projection screen of the present invention has a light source of the projector when viewed from the front of the viewer side, not only has a high brightness and an effect of greatly improving the viewing angle, but also has excellent durability and scratch resistance, especially a roll-type screen It is suitable as.

Description

Durable projection screen {PROJECTION TYPE SCREEN HAVING GOOD DURABILITY}

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 according to another embodiment of the present invention.

4 is a cross-sectional view of a projection screen according to 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

The present invention relates to a projection screen with excellent durability, and more particularly to a projection screen suitable for a 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 enlarging and 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 the 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 problem of weak durability, such as tearing the end of the substrate when applied in a roll type, and does not secure sufficient brightness or viewing angle, and when viewing the screen from the viewer side This seems to have a disadvantage. 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 it is lowered and the process is complicated and the cost is increased when the lens is placed.

Accordingly, the present invention improves the problems of the prior art and provides a projection screen that is not only excellent in durability, but also does not show a light source of the projector when viewed from the front of the viewer, and has a high luminance and greatly improves a viewing angle, and a projection system using the same. The purpose is to do that.

In order to achieve the above technical problem, the present invention has a structure in which a binder resin layer containing beads is laminated on one or both surfaces of a light transmissive substrate, and a light transmitting film softer than the substrate is laminated on the binder resin layer or the substrate surface. It provides a projection screen, including.

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

Projection screens according to one embodiment of the present invention have a binder resin, a curing agent, a colorant, and beads (21, 22) on one side of the substrate (24) in a solvent, as illustrated in FIGS. 2 (a) and (b). The composition prepared by dispersing is applied, and the binder resin layer 23 is formed by applying light or heat, and then an adhesive or an adhesive is applied as the acrylic or urethane-based adhesive or adhesive layer 27, or the adhesive or adhesive tape is used. It manufactures by bonding the flexible light transmissive film 28 for improving durability to the binder resin layer 23 (a) or the base material 24 (b) surface. In this case, the protective film 26 may be positioned on the opposite side of the surface to which the flexible light transmissive film 28 is coupled.

The projection screen according to another embodiment of the present invention has a binder resin, a curing agent, and a bead on both sides of the substrate 24, as illustrated in FIGS. 3 (a) and (b) and 4 (a) and (b). 21, 22) is applied to a composition prepared by dispersing in a solvent, and the binder resin layers 23, 25 are formed by applying light or heat, and then one surface of the binder resin layer (FIG. 1) through an acrylic or urethane adhesive or adhesive layer. 3) or on both sides (FIG. 4) by bonding a soft, transparent film 28 for durability improvement. In this case, as shown in FIG. 3, the protective film 26 may be positioned on the binder resin layer to which the soft light transmissive film 28 is not bonded, and one or both of the binder resin layers may contain a colorant.

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 opacity when folded when applying the projection screen in the 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-transmitting film has a softer property than the substrate used, that is, a property having an elongation of 30% or more and a tensile strength of 500 kg / cm 2 or less, which is generally 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, the durability improvement effect is inadequate. In addition, the film has a light transmittance of 10% or more so as not to deteriorate the physical properties of the screen, it may be used after the treatment such as embossing, hard coating, antiglare, antireflection, etc. as necessary.

After the binder resin-containing composition is applied to the substrate, the curing or curing reaction of the binder resin and the curing agent occurs by light or heat, so that the result of the curing reaction of the binder resin and the curing agent and beads are present in the final binder resin layer. do.

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.

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 the difference of the average particle diameter of these beads is in the range of 0.01 to 100 µm.

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. When the refractive index of the bead is less than 1.30, the viewing angle becomes worse, and when 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. It is preferable that the difference in refractive index of these beads is 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 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 that can be used in the present invention 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 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 a method 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 used. 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.

As the substrate of the present invention, a material having light transmittance 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 beam of the image emitted from the lens of the projector It may be formed of glass to increase the transmittance and the brightness of the screen, and may be formed of a transparent acrylic plate to produce a light weight and low cost. 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.

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 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, it is possible to adjust to the desired brightness and viewing angle according to the bead composition can produce a variety of projection screen products, particularly excellent durability, suitable as a roll-type projection screen product.

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, and then soft light transmissive on the substrate using the following adhesive. The film was bonded.

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

Adhesive: acrylate adhesive

Flexible light transmissive film: PVC film (thickness 40㎛, light transmittance 94%, elongation 80%, tensile strength 200㎏ / ㎠)

<Example 2>

100 weight part of 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 sides 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 sides of the substrate. Then, a soft light-transmissive film was formed thereon using the following adhesive. Adhesion.

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

Adhesive: acrylate adhesive

Flexible light-transmitting film: PVC film (thickness 40㎛, light transmittance 93%, elongation 80%, tensile strength 200kg / ㎠)

<Example 3>

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, 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 base material 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 base material. The light transmissive film was bonded. 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.

[Coloring Binder Resin Layer]

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)

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

          (Weight ratio = 100: 30)

Colorant: Carbon Black

Adhesive: acrylate adhesive

Flexible light transmissive film: PVC film (thickness 40㎛, light transmittance 94%, elongation 80%, tensile strength 200㎏ / ㎠)

[Non-colored Binder Resin Layer]

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)

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 the flexible light-transmissive film was not bonded and only polymethyl methacrylate beads (one type) were 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 the soft light-transmissive film was not adhered and 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 the flexible silicone transparent beads (1 type) were used in an amount of 73.5 parts by weight without bonding the soft light-transmissive film.

<Test Example>

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

Durability Measurement Method

1. Cross hatch test before and after UV irradiation

Using cross hatch testing equipment, draw 100 squares at a time by drawing horizontal and longitudinal lines on the surface of the specimen, attaching 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), and then cut the specimen to be sized to fit the size, fix the empty part with a tape, etc. 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 take-up repetition 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 the luminance meter on the front of the specimen, focus, and use the BM-7 Luminance Colorimeter (TOPCON) as the luminance meter. The normal luminance in the specimen was measured. In addition, the position of the luminance meter was moved 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 luminance, the measurement luminance of Example 1 was evaluated based on 100).

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 Table 1, not only did not use a soft light-transmissive film, but also in the case of a comparative example using a single bead, Comparative Examples 1 and 3 are poor in durability, unsuitable for use as a product because the light source is visible and a large viewing angle Fall off, in the case of Comparative Example 2 especially the brightness is very low; Examples 1 to 3 using a soft light-transmitting film and a mixture of two, three, and four beads having different average particle diameters and refractive indices are excellent in both durability and brightness, and also show no light source. .

The projection 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. 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.

Claims (10)

A projection screen comprising a structure in which a binder resin layer containing beads is laminated on one or both surfaces of a light transmissive substrate, and a light transmitting film softer than the substrate is laminated on the binder resin layer or the substrate surface. The method of claim 1, A projection screen, characterized in that one or both of the binder resin layers contained on one or both surfaces of the light transmissive substrate contain a colorant. The method of claim 1, A projection screen, characterized in that the soft, transparent film has a thickness of at least 10 μm. The method of claim 1, A projection screen, wherein the soft, transparent film has an elongation of at least 30%, a tensile strength of at most 500 kg / cm 2, and a light transmittance of at least 10%. The method of claim 1, A projection screen, characterized in that the soft, transparent film is made of polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), tarpaulin. The method of claim 1, A projection screen, characterized in that the soft, transparent film is embossed, hardcoated, antiglare or antireflective. The method of claim 1, A projection screen, characterized in that the beads are at least two beads having different average particle diameters in the range of 0.1 to 200 μm. The method of claim 1, A projection screen, characterized in that the beads are at least two beads having different refractive indices in the range of 1.30 to 2.50. A front or rear projection imaging system comprising an enlarged projection of an image generated by the image generating apparatus onto the projection screen of claim 1. The method of claim 9, 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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