JP2008281741A - Translucent screen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a translucent screen capable of keeping quality as a screen without spoiling it by maintaining high adhesive property on a boundary between a holding substrate and a joining layer even under a severe environment such as high temperature and high humidity or low temperature. <P>SOLUTION: In the translucent screen constituted by arranging a Fresnel lens sheet and a lenticular lens sheet, the lenticular lens sheet has a light-diffusive holding substrate having high rigidity and also thickness enough to hold the sheet, and is constituted by sticking flexible lens base material provided with a plurality of lenses and a light-shielding layer near them to one surface of the holding substrate through the joining layer, and by sticking flexible surface base material arranged on the outermost surface of a display to the other surface thereof through the joining layer. The hydrogen bonding component of surface free energy is set to 4-10mJ/m<SP>2</SP>at least on one surface of the holding substrate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transmission screen used for a projection display or the like.

  Conventionally, a rear projection television is known as a projection display provided with a transmissive screen. In recent years, MD-type projection televisions have emerged as opposed to thin large-sized displays such as liquid crystal displays (LCDs) and plasma displays (PDPs). An MD projection television, for example, projects projection light modulated using a display device such as an LCD, LCOS (LCD on Silicon), a digital micromirror device (DMD) from the rear side of the transmission screen. Projected. This MD projection television can easily be increased in size to 40 inches or more, has a good image quality because of digital display, and can be manufactured at a relatively low cost. Has been.

  A transmissive screen used in a transflective display such as an MD projection television is composed of a Fresnel lens sheet that adjusts the direction of incident light and emits it as substantially parallel light, and a Fresnel lens to provide an appropriate viewing angle. A lenticular lens sheet that diffuses light emitted from the sheet by, for example, cylindrical lens groups arranged in the horizontal and vertical directions (not limited to the configuration in which the cylindrical lens groups are arranged in one direction, but the cylindrical lens groups are arranged in a plurality of directions). Including various types of light diffusion lens array sheets such as a configuration in which unit lenses are arranged in parallel and a configuration in which unit lenses are two-dimensionally arranged). A diffusion layer for diffusing transmitted light is provided in the Fresnel lens sheet and the lenticular lens sheet in order to reduce luminance unevenness and scintillation. For example, Patent Document 1 discloses a lenticular sheet used for a transmission screen, in which a lens portion in which convex cylindrical lenses are arranged on one side of a transparent support is formed of a cured product of a radiation curable resin. The light-shielding pattern and the diffusion layer are formed on the surface by film transfer or film lamination, and a film having an antistatic function and an antireflection function is further provided on the diffusion layer.

  However, the conventional transmissive screen and the projection display using the same as described above, when the temperature or humidity varies due to differences in the thickness of each layer, the linear expansion coefficient of each layer material, the moisture expansion coefficient, etc. There is a problem in that warping occurs, resolution failure and image blur occur, and image quality deteriorates.

  Therefore, for the purpose of easily preventing deformation of the screen under the environment, in the transmission type screen screen composed of the Fresnel lens sheet and the lenticular lens sheet, the lenticular screen has a lens substrate arranged in the thickness direction, holding It is composed of a substrate and a surface base material, and the lens base material, the holding substrate, and the surface base material are arranged in a substantially symmetrical manner in the thickness direction of the lenticular lens sheet in terms of expansion characteristic values, bending rigidity, and arrangement positions. The applicant made a proposal in Japanese Patent Application No. 2005-374058 (not disclosed at the time of filing this application).

According to the invention described in Japanese Patent Application No. 2005-374058 (unpublished at the time of filing this application), the flatness of the screen is excellent, and since there is almost no warpage occurring at high temperature and high humidity, in severe environments such as high temperature and high humidity. It is possible to maintain good image quality. However, in the invention according to Japanese Patent Application No. 2005-374058 (unpublished at the time of filing of the present application), if the adhesive force of the bonding layer that joins the holding substrate, the lens base material, and the surface base material is insufficient, peeling occurs in the use environment. As a result, the appearance of the display is impaired, and the display quality is deteriorated. In particular, the surface base material that is located on the outermost surface of the display is required to be in close contact with the support.
JP-A-9-120101

  Therefore, in view of the above-described problems, the present invention maintains high adhesion at the interface between the holding substrate and the bonding layer even under severe environments such as high temperature and high humidity and low temperature, and does not impair the quality as a screen. It is an object to provide a transmission screen that can be maintained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. First, the invention of claim 1 comprises a Fresnel lens sheet that makes projection light projected from a light source substantially parallel light, and substantially parallel by the Fresnel lens sheet. In a transmissive screen in which a plurality of lenses that diverge the projected light that is light are arranged, and a lenticular lens sheet that is provided with a light shielding layer in the vicinity of the plurality of lenses,
The lenticular lens sheet has a light-diffusing holding substrate having a high rigidity and a thickness capable of holding the sheet, and the plurality of lenses are provided on one surface of the holding substrate, and a light shielding layer is provided in the vicinity thereof. The flexible lens substrate is bonded via the bonding layer, and the flexible surface substrate disposed on the outermost surface of the display is bonded via the bonding layer to the other surface. A combined lenticular lens sheet,
The transmission type screen is characterized in that a hydrogen bond component of surface free energy is 4 to 10 mJ / m ² on at least one surface of the holding substrate.

  The invention according to claim 2 is the transmission type screen according to claim 1, wherein a methyl methacrylate / styrene copolymer resin is used as the holding substrate and an acrylic polymer is used as the bonding agent.

  The invention according to claim 3 is the transmission type screen according to claim 3, wherein the surface free energy of the holding substrate made of methyl methacrylate / styrene copolymer resin is adjusted by surface cleaning.

  The present invention provides a transmissive screen capable of maintaining high adhesion at the interface between the holding substrate and the bonding layer and maintaining the quality as a screen even under severe environments such as high temperature and high humidity and low temperature. There is an effect that can be done.

  Hereinafter, a transmission screen according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional explanatory diagram for explaining a configuration of a transmission screen according to an embodiment of the present invention. Since this drawing is a schematic diagram, the shape and dimensions are exaggerated (the same applies below).

As shown in FIG. 1, the transmissive screen 10 of the present embodiment has a Fresnel lens sheet 20 having a Fresnel lens portion 21 that adjusts the direction of incident light and uses it as outgoing light, and the outgoing light from the Fresnel lens sheet 20 is screened. And a lenticular lens sheet 30 that is an optical member having a cylindrical lens 41 that diffuses in the horizontal direction (vertical direction in FIG. 1) and the vertical direction (vertical direction in FIG. 1).

  The Fresnel lens sheet 20 and the lenticular lens sheet 30 are sequentially arranged from the back side (left side in FIG. 1) to the front side (right side in FIG. 1) of the transmissive screen 10 and are arranged substantially parallel to each other. . In the following description, the Fresnel lens sheet 20 side direction and the lenticular lens sheet 30 side direction of the right and left directions shown in the drawing will be referred to as the observation side direction, respectively.

  In the present embodiment, the base material of the Fresnel lens is a light diffusing base material 22 having light diffusibility as a whole as shown in FIG. 1, the thickness thereof is 0.8 mm to 1.5 mm, and the diffusion degree is haze. Although the value is set to 50% to 70%, a structure formed by a combination of a light diffusing layer and a transparent layer may be used.

  As shown in FIG. 1, the lenticular lens sheet 30 includes, from the light source side, a cylindrical lens 41, a light transmitting base material 42, a black stripe (BS) layer 43, a bonding layer 61, a transparent or slightly diffusive holding substrate 60, and a bonding layer. 62, a light diffusing layer 53, a light transmissive substrate 51, and a surface coat layer 52 are arranged in a layer form in this order, and are flat plate members that are attached in a flat state without being bent by giving initial deformation or the like during assembly. is there. The shape viewed from the optical axis direction is a substantially rectangular shape similar to the outer shape of the Fresnel lens sheet 20.

  The cylindrical lens 41 has a substantially semi-cylindrical shape, and a plurality of cylindrical lenses 41 are arranged substantially parallel to each other to form an incident surface of the lenticular lens sheet 30.

  The light transmissive substrate 42 is a light transmissive substrate provided to support the cylindrical lens 41 and is made of polyethylene terephthalate (PET) resin.

  The BS layer 43 is stripped on the front side of the plurality of cylindrical lenses 41 by an appropriate range by a light absorption band extending in a stripe shape along the generatrix direction of the cylindrical lenses 41 at the non-condensing portion of each cylindrical lens 41. The light is shielded in a shape. Between each BS layer 43, a light-transmitting bonding layer 61 for bonding the light-transmitting base material 42 and the transparent or slightly light-diffusing holding substrate 60 is provided. The bonding layer 61 is selected from an adhesive or an active energy ray (for example, ultraviolet ray) curable adhesive, and its thickness including the BS layer 43 is 50 μm or less.

  Since the transparent or slightly diffusive holding substrate 60 bears the main part of the rigidity of the lenticular lens sheet 30, the thickness thereof is larger than the thickness of the light transmitting base materials 42 and 51, and MMA is 60 as the main material. % MS resin can be employed. The thickness of the transparent or slightly diffusive holding substrate 60 of this embodiment is set to 1.85 mm.

  The surface substrate 50 includes a light transmitting substrate 51, a surface coat layer 52, and a light diffusion layer 53. The light transmissive substrate 51 is made of the same PET resin material as the light transmissive substrate 42 and has the same thickness. In this embodiment, the thickness is set to 75 μm. The diffusion degree of the light diffusion layer 53 of this embodiment is a haze value and is set to 75% to 85%.

In the lenticular lens sheet 30 configured as described above, by setting the hydrogen bond component of the surface free energy of the transparent or microdiffusible holding substrate 60 to 4 to 10 mJ / m ² , High adhesion is maintained at the interface with the bonding layers 61 and 62, and good image quality can be maintained even under severe environments such as high temperature and high humidity or low temperature.

  Next, examples of the transmission screen according to the embodiment of the present invention and comparative examples will be described.

  In the present example and the comparative example, a plate made of MS resin having a thickness of 1.85 mm was adopted as the transparent or microdiffusible holding substrate 60. Hereinafter, the transparent or slightly diffusive holding substrate 60 is also referred to as a plate 60.

<Example>
First, one surface of the plate 60 was wiped with a waste cloth containing IPA and naturally dried.

An acrylic UV curable adhesive is applied to the surface of the plate 60 that has been subjected to IPA wiping and cleaning with a roll coater, and the light diffusion layer 53 side of the surface base material 50 is superimposed on the adhesive coating surface, and the hardness of 60 degrees is applied. Laminate with a rubber roll at room temperature at a pressure of 0.45 MPa and a laminating speed of 1 m / min, and with UV light using a high-pressure mercury lamp as a light source with an integrated light amount of 1,500 mJ / cm ² from the surface coat layer 52 side of the surface substrate 50. Irradiated.

Subsequently, an acrylic ultraviolet curable adhesive is applied to the surface of the plate 60 on which the surface base material 50 is not laminated with a roll coater, and the BS layer 43 side of the lens base material 40 is overlapped on the adhesive coating surface. Laminating with a rubber roll at room temperature of 60 degrees at a pressure of 0.45 MPa and a laminating speed of 1 m / min, and using a high-pressure mercury lamp with an integrated light amount of 1,500 mJ · cm ² from the cylindrical lens 41 side of the lens substrate 40 as a light source, Irradiated with ultraviolet rays.

  As described above, a lenticular lens sheet 30 as shown in FIG. 1 was obtained.

  In the lenticular lens sheet 30 according to the present example, the adhesive force at the interface between the plate 60 and the bonding layer 62 was 18 N / inch, which showed a sufficiently strong adhesive force.

<Comparative example>
A lenticular lens sheet was produced in the same manner as in the example except that the surface of the plate 60 on which the surface base material 50 was laminated was not subjected to IPA wiping and washing. In this lenticular lens sheet, the adhesion at the interface between the plate 63 and the bonding layer 62 was 11 N / inch, indicating weaker adhesion than the examples.

  The results of Examples and Comparative Examples will be described below based on Table 1.

表１に記した表面自由エネルギーは液滴接触角法にて測定した値である。

The surface free energy shown in Table 1 is a value measured by a droplet contact angle method.

As shown in Table 1, in the example in which the adhesion at the interface between the plate 60 and the bonding layer 62 is strong, the hydrogen bond component of the surface free energy is as large as 5.0 mJ / m ^{2 as} compared with the comparative example. Since the other components were almost the same, it was found that the hydrogen bonding component on the surface of the plate 60 was greatly involved in the adhesion. The hydrogen bonding component of the bonding layer 62 made of acrylic resin also shows a large value of 7.3 mJ / m ^2, and it is preferable to arrange a material having the same degree of hydrogen bonding component for the acrylic resin. Adhesion was obtained.

It is a section explanatory view for explaining the composition of the transmission type screen concerning one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Transmission type screen 20 ... Fresnel lens sheet 21 ... Fresnel lens part 22 ... Light diffusion base material 30 ... Lenticular lens sheet 40 ... Lens base material 41 ... Cylindrical lens 42 ... Light transmission base material 43 ... BS layer 50 ... Surface base material DESCRIPTION OF SYMBOLS 51 ... Light-transmitting base material 52 ... Surface coat layer 53 ... Light diffusion layer 60 ... Transparent or slightly diffusive holding substrate 61 ... Bonding layer 62 ... Bonding layer

Claims (3)

A Fresnel lens sheet that makes the projection light projected from the light source substantially parallel light, and a plurality of lenses that diverge the projection light that has been made substantially parallel light by the Fresnel lens sheet are arranged, and a light shielding layer in the vicinity of the plurality of lenses In a transmissive screen formed by arranging a lenticular lens sheet provided with
The lenticular lens sheet has a light-diffusing holding substrate having a high rigidity and a thickness capable of holding the sheet, and the plurality of lenses are provided on one surface of the holding substrate, and a light shielding layer is provided in the vicinity thereof. The flexible lens substrate is bonded via the bonding layer, and the flexible surface substrate disposed on the outermost surface of the display is bonded via the bonding layer to the other surface. A combined lenticular lens sheet,
A transmissive screen, wherein a hydrogen bond component of surface free energy is 4 to 10 mJ / m ² on at least one surface of the holding substrate.   2. The transmission screen according to claim 1, wherein a methyl methacrylate / styrene copolymer resin is used as a holding substrate and an acrylic polymer is used as a bonding agent.   4. The transmission screen according to claim 3, wherein the surface free energy of the holding substrate made of methyl methacrylate / styrene copolymer resin is adjusted by surface cleaning.

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