JP2012150355A - Display device and method for manufacturing optical sheet included in the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device capable of improving both front brightness and contrast with a simpler structure.SOLUTION: An optical sheet includes a wavelength filter layer, and the wavelength filter layer includes a light absorbing layer including an adhesive and having a wavelength filter function to absorb light of a part of a wavelength region of visible light for attenuating the light quantity and a light transmitting layer disposed to be closer to an observer side than the light absorbing layer, forming an interface with the light absorbing layer and transmitting light. The light transmitting layer includes a plurality of unit light transmitting projections projecting toward the light absorbing layer and arranged along a vertical direction. Each unit light transmitting projection has a first face corresponding to an upper face inclined by an angle θagainst a normal direction of a sheet surface on the observer side of the optical sheet and a second face corresponding to a lower face inclined by an angle θagainst the normal direction, the angle θis smaller than the angle θ, and each unit light transmitting projection has the same refractive index as the light absorbing layer.

Description

  The present invention relates to a display device that appropriately transmits and absorbs image light and external light and provides a high-quality image to an observer, and a method for manufacturing an optical sheet included in the display device.

  In a display device such as a plasma television using a plasma display panel (hereinafter sometimes referred to as “PDP”), an optical sheet is arranged on the viewer side of the PDP. This optical sheet has a function of providing a high-quality image to an observer.

  There are various factors in image quality, among which are front brightness and contrast. Front luminance means the brightness of image light emitted from the screen in the front direction. If the front brightness is low, the observer will feel that the screen is dark, so it cannot be said that the image light is of good quality, and the display device needs to ensure a certain level of front brightness. On the other hand, contrast means a light / dark ratio of a bright part and a dark part in an image. When the contrast is high, the outline of the object is clearly expressed, and a so-called sharp image is obtained. On the other hand, when the contrast is low, the overall brightness tends to be the same, so that the outline of the object is blurred and the image has no sharpness. Therefore, from the viewpoint of obtaining high quality image light, it is necessary to secure a certain level of contrast.

  Conventionally, in order to improve contrast, an ND filter layer, a toning filter layer, a neon light absorption layer, or a combination of these may be included as one layer of the optical sheet. These ND filter layer, toning adjustment filter layer, and neon light absorption layer are all layers that have the property of reducing the amount of light. Among them, an ND filter (Neutral Density Filter) layer is a layer that can reduce the amount of light regardless of the wavelength of light when reducing the amount of light. On the other hand, layers that can attenuate the amount of light having a wavelength in a predetermined range are a toning adjustment filter layer and a neon light absorption layer. Hereinafter, these are collectively referred to as a wavelength filter layer. Such a function may be referred to as a “wavelength filter function”.

  A display device including such a wavelength filter layer is disclosed in, for example, Patent Document 1, which has a wavelength filter function in an adhesive. External light is once transmitted through the wavelength filter layer (adhesive layer) by being incident on the optical sheet, and then reflected by any part of the display device and emitted to the viewer side once again. The agent layer). Accordingly, when the light passes through the wavelength filter layer at least twice, external light is absorbed, and a large amount of external light is absorbed to improve the contrast. On the other hand, the image light only passes through the wavelength filter layer once when emitted from the image source to the viewer side. Therefore, by providing the wavelength filter layer, it is possible to ensure a large improvement in contrast compared to a reduction in the luminance of the image light, and it is possible to ensure the front luminance and the contrast to some extent.

  On the other hand, Patent Documents 2 and 3 disclose optical sheets that can improve the front luminance and contrast. This includes a light transmission part (prism part) formed at a predetermined interval on one surface of the base material layer, and a wedge-shaped light absorption part arranged between the light transmission parts (prism part). Appears.

International Publication Gazette WO 2008/038729 JP 2009-080153 A JP 2009-080193 A

  However, in order to obtain a high contrast with the wavelength filter layer as in Patent Document 1, it is necessary to reduce the transmittance, and the luminance of the image light is greatly reduced accordingly. In order to increase the luminance of the image light, it is necessary to take a method of increasing the output of the image source itself to make it brighter, resulting in an increase in power consumption.

  On the other hand, the optical sheets configured as in Patent Document 2 and Patent Document 3 can improve both the front luminance and the contrast, but have a complicated structure. Such a small and highly accurate structure takes time and effort for quality control, and it has been difficult to keep costs low.

  In view of the above problems, the present invention provides a display device capable of improving both front luminance and contrast with a simpler configuration. Moreover, the manufacturing method of the optical sheet contained in such a display apparatus is provided.

  The inventor has obtained the following knowledge in completing the present invention. FIG. 7 shows a diagram for explanation. First, as shown on the left side of FIG. 7A, a light absorption layer having a constant thickness D is considered. When light is transmitted through the light absorption layer in the thickness direction, the light transmittance is the same in any of the portions indicated by A, B, and C in FIG. This is represented on the right side of FIG. However, this graph is conceptually represented and not accurately displayed. In the graph of FIG. 7A, the horizontal axis represents the transmittance, and the vertical axis represents the position (position in the direction orthogonal to the thickness direction). As can be seen from the graph in FIG. 7A, the transmittance is constant regardless of the position.

Next, as shown on the left side of FIG. 7B, the light absorption layer is formed of a composition having the same volume and the same light absorption performance as the light absorption layer shown in FIG. Think about the layer. This is formed so that the thickness differs depending on the position. Specifically, it is a right triangle with AC as the base and a height of 2 · D. The position of B is the midpoint of AC. FIG. 7B also shows a graph similar to that in FIG.
When light passes through the light absorbing layer in the thickness direction, the thickness of the light absorbing layer at the position A is 0, the thickness at the position B is D, and the thickness at the position C is 2 · D. If the transmittance is proportional to the thickness of the light absorption layer, p and q shown in the graph of FIG. 7B should be equal. In practice, however, q is smaller than p. Therefore, the transmittance is not proportional to the thickness of the light absorption layer, and the degree of decrease in the transmittance decreases as the thickness increases to some extent.

  In view of the above, the average value of the transmittance between the positions A to C of the light absorption layer whose thickness varies depending on the position (example in FIG. 7B) is the same as the volume and the like. Becomes larger than the average value of the transmittance between the positions A to C in the light absorption layer (an example in FIG. 7A). That is, the example of FIG. 7B means that the transmittance is higher as a whole.

  On the other hand, it is known that the absorbance, also called OD value, is proportional to the thickness of the light absorption layer.

  Obtaining the above knowledge, the inventors completed the present invention. The present invention will be described below.

The invention according to claim 1 is a display device that provides an image to an observer, and is arranged on an observer side from the image source and controls the image light from the image source to control the observer side. An optical sheet having a plurality of layers capable of emitting light to the optical sheet, the optical sheet including a wavelength filter layer that attenuates and transmits at least a part of the wavelength region of visible light, and the wavelength filter layer is optical A light absorption layer including a pressure-sensitive adhesive layer that includes a pressure-sensitive adhesive for laminating and fixing a sheet to an image source and that can absorb light in at least a part of the wavelength region of visible light and attenuate the amount of light. And a light transmission layer that is disposed on the viewer side of the light absorption layer and forms an interface with the light absorption layer and transmits light, and the light transmission layer projects toward the light absorption layer side. And a plurality of lines arranged in the vertical direction. Includes a position light transmitting convex portion, the unit light transmitting convex portion is a corner theta ₁ formed by the normal line direction of the observer's side seat surface of the optical sheet, a first surface serving as an upper surface side of the convex optical sheet The angle formed with the normal direction of the observer-side sheet surface is θ ₂ , and the second surface is the convex lower surface side, and θ ₁ is smaller than θ _{2 and} the refractive index of the unit light transmitting convex portion Is a display device having the same refractive index as the light absorption layer.
Here, “the refractive index is the same” means that the refractive index difference is 0.02 or less. The same applies hereinafter.

The invention according to claim 2 is a display device that provides an image to an observer, and is arranged on an observer side from the image source and controls the image light from the image source to control the observer side. An optical sheet having a plurality of layers capable of emitting light to the optical sheet, and the optical sheet includes a wavelength filter layer that attenuates and transmits at least part of the wavelength region of visible light, and the wavelength filter layer includes: It includes a pressure-sensitive adhesive that includes a wavelength filter layer that is laminated and fixed to another layer, and that has a wavelength filter function capable of absorbing light in at least a part of the wavelength region of visible light and attenuating the amount of light. A light-absorbing layer, and a light-transmitting layer that is disposed on the image source side of the light-absorbing layer and forms an interface with the light-absorbing layer and transmits light. The light-transmitting layer is disposed on the light-absorbing layer side. Convex-facing and aligned in the vertical direction Comprising a unit light transmitting convex portion of the number, the unit light transmitting convex portion is ₃ corners θ formed by the normal direction of the image source side seat surface of the optical sheet, a first surface serving as an upper surface side of the convex, optical An angle formed with the normal direction of the image source side sheet surface of the sheet is θ ₄ , and a second surface which is a convex lower surface side, and θ ₄ is smaller than θ _{3 and} the refraction of the unit light transmitting convex portion The index is the same as the refractive index of the light absorption layer.

  According to a third aspect of the present invention, in the display device according to the first or second aspect, at least one of an electromagnetic wave shielding layer and a hard coat layer is disposed on the viewer side of the wavelength filter layer.

  According to a fourth aspect of the present invention, in the display device according to the first aspect, a conductor mesh layer having an electromagnetic wave shielding function is formed on the viewer side of the wavelength filter layer.

  Invention of Claim 5 is a method of manufacturing the optical sheet contained in the display apparatus as described in any one of Claims 1-4, Comprising: It respond | corresponds to the shape of the unit light transmissive convex part of a light transmissive layer. The base material is inserted between the mold roll having the surface shape and the nip roll, the composition is filled between the base material and the mold roll, and the composition is irradiated with ultraviolet rays. It is a manufacturing method of an optical sheet including the process of making it harden and forming a unit light transmission convex part.

  The invention according to claim 6 is a method for manufacturing an optical sheet included in the display device according to any one of claims 1 to 4, wherein the gold sheet has holes corresponding to the cross-sectional shape of the light transmission layer. This is a method for producing an optical sheet including a step of pressurizing and pressing a composition melted by heating into a mold and cooling a composition flowing out from a hole of a mold to form a light transmission layer.

  Invention of Claim 7 is a method of manufacturing the optical sheet contained in the display apparatus as described in any one of Claims 1-4, Comprising: The composition which comprises a light absorption layer is apply | coated to a peeling sheet And then, a method for producing an optical sheet including a step of laminating the composition on the light transmission layer.

  Invention of Claim 8 is a method of manufacturing the optical sheet contained in the display apparatus as described in any one of Claims 1-4, Comprising: The composition which comprises a light absorption layer is light-transmitted directly. It is a manufacturing method of an optical sheet including the process applied to a layer.

According to the display device of the present invention, it is possible to improve both the front luminance and the contrast with a simpler configuration.
Moreover, according to the method of manufacturing an optical sheet included in this display device, the above-described display device can be manufactured even more easily.

1 is an exploded perspective view schematically showing a display device according to a first embodiment. It is the figure which showed the cross section of the image | video source unit, and represented the layer structure typically. It is the figure which expanded and showed the wavelength filter layer. It is a figure explaining the example of an optical path. It is the figure which showed the cross section of the video source unit contained in the display apparatus concerning 2nd embodiment, and represented the layer structure typically. It is the figure which expanded and showed the wavelength filter layer. It is a figure explaining the transmittance | permeability. It is a figure explaining the conditions of evaluation in an example.

  The above-described operation and gain of the present invention will be clarified from embodiments for carrying out the invention described below. Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to the embodiment.

  FIG. 1 is an exploded perspective view schematically showing a display device 1 according to the first embodiment. In FIG. 1, the upper right side of the page is the observer side, and the lower left side of the page is the back side. As can be seen from FIG. 1, in the display device 1, the video source unit 4 is disposed inside the casing formed by the front casing 2 and the rear casing 3. The display device 1 of the present embodiment is a plasma television, and the video source unit 4 is a plasma display panel unit 4 (PDP unit 4). In addition to the video source unit 4, the display device 1 includes various known devices that are to be provided in the display device in the housing. Examples thereof include various electric circuits and cooling means.

  FIG. 2 is a diagram schematically showing the layer structure of the video source unit 4 shown in FIG. FIG. 2 is a cross section taken along the line II-II in FIG. 1, and the right side of the page is the observer side. In FIG. 2, some repetitive symbols may be omitted for the sake of clarity (the same applies to the following drawings). FIG. 3 shows an enlarged view of a part of the wavelength filter layer 11 in FIG.

  As can be seen from FIG. 2, the video source unit 4 includes a PDP 5 and an optical sheet 10 laminated on the PDP 5. Here, as the PDP 5, a known PDP can be used. Hereinafter, the optical sheet 10 will be described.

  The optical sheet 10 includes a wavelength filter layer 11, an electromagnetic wave shielding layer 18, and a hard coat layer 19.

  The wavelength filter layer 11 includes a light transmission layer 12 and a light absorption layer 15, which are stacked in the thickness direction of the optical sheet 10. Details are as follows.

  The light transmission layer 12 is a layer that transmits light and forms an uneven surface at the interface with the light absorption layer 15. As shown in FIGS. 2 and 3, the light transmission layer 12 includes a base material portion 13 and a light transmission uneven portion 14, and the light transmission uneven portion 14 is provided with a plurality of unit light transmission convex portions 14 a. It has been.

  The base material part 13 is a part which becomes translucent and becomes a base material of the light transmission uneven part 14, and supports the light transmission uneven part 14 so as to prevent deformation. From this point of view, as specific examples of the material forming the base portion 13, for example, a transparent resin mainly composed of one or more of acrylic, styrene, polycarbonate, polyethylene terephthalate, acrylonitrile, epoxy acrylate or urethane acrylate based reactivity Resin (ionizing radiation curable resin etc.) can be mentioned.

  The light transmission uneven portion 14 is a portion provided with a plurality of unit light transmission convex portions 14a having translucency. Each unit light transmission convex part 14a is formed so as to protrude toward the light absorption layer 15 side. In this embodiment, the cross section has a portion that is substantially triangular, and includes a first surface 14b and a second surface 14c that form the hypotenuse. The unit light transmission convex portions 14a are formed so as to have the cross section shown in FIG. 2 and to extend in the back / front direction of the paper, and are juxtaposed in a direction orthogonal to the extending direction.

Specifically, as shown in FIG. 3, the angle formed by the first surface 14 b and the observer-side sheet surface normal of the optical sheet 10 is θ ₁ , and the second surface 14 c is the observer-side sheet surface of the optical sheet 10. when the normal line angle was theta _2, which in this embodiment is θ _{1 <θ 2.}

Specific angles of θ ₁ and θ ₂ are not limited, but θ ₂ is preferably 20 degrees or more and 40 degrees or less, and more preferably 25 degrees or more and 35 degrees or less. For example, θ ₂ can be obtained as follows. That is, when external light incident on the optical sheet from an oblique angle of 45 degrees is considered, and the light transmission layer 12 is made of an acrylic resin having a refractive index of 1.49, the external light is above the horizontal according to Snell's law. Since the light travels through the light-transmitting concavo-convex portion 14 so as to descend from 28.3 degrees obliquely, θ ₂ can also be set to 28.3 degrees accordingly.

Meanwhile, theta ₁ is similar to the theta _2, from the viewpoint of more effectively absorb external light from the ceiling direction in the room, preferably 0 ° ≦ θ _{1 <θ 2,} more preferably from 0 ° . In general, the amount of external light is higher from the upper side than the lower side. Therefore, if the relationship θ ₁ <θ ₂ is satisfied, the efficiency of absorbing the external light is better.

  It is preferable that the pitch of the unit transmission convex part 14a is 10 micrometers or more and 50 micrometers or less from a viewpoint of forming workability and the light absorption layer 15 mentioned later. For the same reason, the protrusion height of the unit transmission convex portion 14a is preferably 20 μm or more and 100 μm or less.

  Here, the light transmission uneven portion 14 may be the same material as the base material portion 13 or may be a different material. However, if there is a difference in refractive index, light is deflected at this interface due to the difference in refractive index. Therefore, it is preferable that the materials be the same, or even if they are different materials. In the case of the same material, the light transmission uneven part 14 and the base material part 13 can also be formed integrally. Further, even when the light transmission uneven portion 14 and the base material portion 13 are different materials and the same material, the base material portion 13 and the light transmission uneven portion 14 are separately formed and laminated by some means. May be. An example of a method for forming the light transmission layer 12 will be described later.

  The material for forming the unit light transmitting convex portion 14a is not particularly limited, but specific examples include, for example, a transparent resin mainly composed of one or more of acrylic, styrene, polycarbonate, polyethylene terephthalate, acrylonitrile, and epoxy acrylate. And urethane acrylate-based reactive resins (ionizing radiation curable resins, etc.).

  However, the unit light transmission convex part 14a has the same refractive index as the unit light absorption convex part 17a of the light absorption layer 15 described later. Here, “the same refractive index” means that the refractive index difference is within 0.02.

The light absorption layer 15 is a layer having a wavelength filter function that is combined with the light transmission layer 12 described above. In the present embodiment, the light absorption layer 15 includes an adhesive, and also has a function as an adhesive layer that appropriately adheres the optical sheet 10 to another layer such as a PDP or a glass layer.
In the present embodiment, the light absorbing layer 15 has a function as a pressure-sensitive adhesive layer, but this is not always necessary, and the pressure-sensitive adhesive layer may be provided separately. However, by providing the light absorbing layer 15 also with a function as an adhesive layer, there is an advantage that the layer configuration can be simplified. From this point of view, in this embodiment, the light absorption layer 15 is a layer having an adhesive function.

  Therefore, the light absorption layer 15 includes a pressure-sensitive adhesive and light absorption means contained in the pressure-sensitive adhesive. The light absorbing means is a means that exhibits a wavelength filter function having a light absorbing action such as one or more kinds of light absorbing agents and light absorbing dyes that can absorb light in a desired wavelength region.

The adhesive is a substance that adheres and fixes the optical sheet 10 to another member such as a PDP or a glass panel. The material used as the pressure-sensitive adhesive is not particularly limited, but is widely used as a pressure-sensitive adhesive used in an optical sheet incorporated in a display device, and has optical characteristics, stability, ease of lamination, etc. and is available at a low price. It is preferable to use possible materials.
For example, an acrylic pressure-sensitive adhesive can be used, and more specifically, a pressure-sensitive adhesive combining an acrylic copolymer and an isocyanate compound can be used.

  The light absorbing means is a substance that can absorb light in a desired wavelength region, and a known material that can absorb light having a wavelength to be attenuated can be used as the material. Since one type of light absorbing means cannot attenuate visible light in all wavelength regions, multiple types of light absorbing means are applied to appropriately cover the wavelength range of light that can be attenuated. May be. Examples of light absorbing means are given below.

Examples of light absorbing means capable of absorbing light having a wavelength of 550 nm or more and 640 nm or less include cyanine-based, oxonol-based, methine-based, subphthalocyanine-based or porphyrin-based dyes. According to this, light in this wavelength region can be absorbed and attenuated.
Here, since this wavelength region includes neon light radiated from the PDP, that is, the emission spectrum band of neon atoms, if the light absorbing means is included, a so-called neon line absorbing function is provided.

In addition, a well-known light absorbing means having a maximum absorption wavelength in any of the visible region of 380 nm or more and 780 nm or less can be used. Examples thereof include the means described in JP 2000-275432 A, JP 2001-188121 A, JP 2001-350013 A, JP 2002-131530 A, and the like. In addition to this, means such as anthraquinone, naphthalene, azo, phthalocyanine, pyromethene, tetraazaporphyrin, squarylium, cyanine, etc. that absorb visible light such as yellow light, red light, blue light, etc. It can also be mentioned.
If such light absorbing means is included, the color purity and color reproduction range of light emitted from the PDP and the display color when the power is turned off can be improved, and so-called color tone adjustment function is provided. It becomes.

  Moreover, you may use a light absorptive colored particle as a light absorption means. Examples thereof include organic fine particles colored with metal salts such as carbon black, graphite and black iron oxide, dyes, pigments, colored glass beads, and the like. More specifically, there are acrylic crosslinked fine particles containing carbon black, urethane crosslinked fine particles containing carbon black, and the like.

  That is, the light absorption layer 15 can be manufactured by making a light absorption means turbid in an adhesive constituent composition.

  As can be seen from FIGS. 2 and 3, the light absorption layer 15 is laminated on the surface of the light transmission layer 12 on the side where the light transmission uneven portion 14 is provided. As a result, a part of the light absorption layer 15 enters between the unit light transmission convex portions 14a to form a unit light absorbing convex portion 17a. Thereby, the light absorption layer 15 is formed so as to protrude toward the light transmission layer 12 side of the base portion 16 having a constant thickness, and a light absorption uneven portion including a plurality of unit light absorption convex portions 17a. 17. As can be seen from FIGS. 2 and 3, the light transmission uneven portion 14 and the light absorbing uneven portion 17 are formed so as to fill the unevenness. Accordingly, the first surface 17b of the unit light absorbing convex portion 17 is formed so as to overlap with the first surface 14b of the unit light transmitting convex portion 14a, and similarly, the second surface 17c is formed so as to overlap with the second surface 14c. .

  Further, the formed light absorption layer 15 has at least the same refractive index as the unit light transmission convex portion 14 a in the light transmission layer 12.

  Here, in this embodiment, the light absorption layer 15 includes a base portion 16 and a light absorption uneven portion 17. As described with reference to FIG. 7 described above, the portion having the unevenness contributes to the improvement of the transmittance, and the light absorption uneven portion 17 in the present embodiment. Therefore, the base portion 16 may be made as thin as possible, and the light absorption layer may be formed only by the light absorption uneven portion without the base portion. In the present embodiment, the base 16 is provided from the viewpoint that the light absorption layer 15 also has a function as an adhesive layer and from the viewpoint of productivity.

  Returning to FIG. 2, the electromagnetic wave shielding layer 18 will be described. The electromagnetic wave shielding layer 18 has a function of shielding electromagnetic waves generated from a PDP or the like. As the electromagnetic wave shielding layer, various types of conventionally known forms can be applied. In addition to a conductor mesh layer exemplified later, transparent such as silver, ITO (indium tin oxide), ATO (antimony-doped tin oxide), etc. It is also possible to use a continuous (non-mesh opening) thin film. However, a conductive mesh layer made of metal or the like is preferable from the viewpoint of achieving both transparency and electromagnetic shielding properties.

In the present embodiment, as shown in FIG. 2, the electromagnetic wave shielding layer 18 includes a base material portion 13 of the light transmission layer 12 described above and a conductor mesh layer 18a laminated thereon. Yes.
In general, a known electromagnetic wave shielding layer generally has a structure having a transparent base material and a conductive mesh layer laminated on the surface thereof. On the other hand, in this embodiment, the base material portion 13 of the light transmission layer 12 also functions as a transparent base material of the electromagnetic wave shielding layer. Therefore, according to the present embodiment, the layer configuration can be simplified.
However, this does not prevent application of a known electromagnetic wave shielding layer in which a conductive mesh layer is laminated on a transparent substrate separately provided as in the conventional electromagnetic wave shielding layer. It may be laminated on the light transmission layer 12.

  The conductor mesh layer 18a is a layer that exhibits an electromagnetic wave shielding function by having conductivity, and the linear members (lines) constituting the mesh itself are opaque, but the lines are mesh-like (fine lattice). Thus, an opening is formed and light can be transmitted.

The shape of the mesh is not particularly limited, but a typical example is that the shape of the opening is a square. In addition, for example, a triangle, a rectangle, a polygon, a circle, an ellipse, or the like may be used.
The line width of the mesh is 100 μm or less, more preferably 50 μm or less, from the viewpoint of non-visibility of the mesh. However, the thickness is preferably 5 μm or more from the viewpoint of securing the electromagnetic wave shielding function and preventing breakage.
The width of the opening of the mesh is 100 μm or more, more preferably 150 μm or more. However, a maximum of 3000 μm is preferable from the viewpoint of securing the electromagnetic wave shielding function.
Further, the relationship between the line width and the opening width is such that the aperture ratio is 60% or more from the viewpoint of light transmittance and from the viewpoint that bubbles do not easily remain in the opening when the hard coat layer is formed. From the viewpoint of securing the electromagnetic wave shielding function, it is preferable to set it to 97% or less. In the case where the opening is a square, the opening ratio is defined as: [(width of opening) ² / (line pitch) ² ] × 100%.
The thickness of the conductor mesh layer 18a is preferably 1 μm or more and 20 μm or less from the viewpoint of the electromagnetic wave shielding function. However, the thin film, the visibility of the image, the viewpoint of mixing of bubbles when forming the hard coat layer, the process is short, and the yield is short. From a good point etc., More preferably, they are 1 micrometer or more and 5 micrometers or less, More preferably, they are 1 micrometer or more and 3 micrometers or less.

  Such a conductor mesh layer 18a can be formed by a known method. For example, a method of printing a conductive ink on the base material portion 13 of the light transmission layer 12 in a mesh pattern and metal plating on the formed conductive ink layer can be exemplified.

Moreover, you may provide a blackening layer and a rust prevention layer in the conductor mesh layer 18a like a well-known conductor mesh layer.
The blackening layer can be provided for the purpose of absorbing external light, improving image visibility, improving contrast, and the like. Such a blackening layer can be provided by applying a light-absorbing substance over the visible light region.
The rust preventive layer is provided for the purpose of preventing rust and preventing the blackened layer from dropping or deforming. As the anticorrosive layer, for example, nickel, zinc, and / or copper oxide, or a chromate treatment layer can be applied.

Next, the hard coat layer 19 will be described. The hard coat layer 19 may be referred to as a surface protective layer or an HC layer, and is a layer having a function of protecting the viewer side surface of the optical sheet 10. The hard coat layer 19 can be formed as a transparent resin layer, and the hard coat layer 19 is preferably formed as a cured resin layer formed by curing a curable resin from the viewpoint of resistance to scratches and surface contamination.
Specifically, an ionizing radiation curable resin, other known curable resins, or the like may be appropriately employed according to the required performance. Examples of the ionizing radiation curable resin include acrylate-based, oxetane-based, and silicone-based resins. For example, acrylate-based ionizing radiation curable resins include monofunctional (meth) acrylate monomers, bifunctional (meth) acrylate monomer monomers, (meth) acrylate monomers such as trifunctional or higher (meth) acrylate monomers, urethane ( It consists of (meth) acrylate ester oligomers such as (meth) acrylate, epoxy (meth) acrylate, and polyester (meth) acrylate, or (meth) acrylate prepolymers. Examples of tri- or higher functional (meth) acrylate monomers include trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like.

  In addition, a silicone compound, a fluorine compound, or the like may be added to the hard coat layer 19 from the viewpoint of improving the stain resistance.

  The optical sheet 10 having such a configuration is disposed on the PDP 5 to form the video source unit 4. Specifically, as can be seen from FIG. 2, the light absorption layer 15 is directed to the PDP 5 side, and the optical sheet 10 is directly laminated on the PDP 5 by its adhesive function. At this time, in this embodiment, in the unit light transmission convex part 14a of the light transmission layer 14, it arrange | positions so that the 1st surface 14b may become upper and the 2nd surface 14c may become lower. Accordingly, the unit light transmitting convex portion 14a and the unit light absorbing convex portion 17a are arranged in parallel in the vertical direction with the horizontal direction as the longitudinal direction.

  That is, in the display device 1, the optical sheet 10 is laminated on the viewer side surface of the PDP 5 in the video source unit 4. In the present embodiment, the PDP 5 and the optical sheet 10 are adhered by the light absorption layer 15. Further, a light transmission layer 12 is laminated on the observer side, a conductor mesh layer 18a is laminated on the side of the observer of the light transmission layer 13, and a hard coat layer 19 is formed on the observer side.

  Such an optical sheet 10 can be manufactured, for example, as follows.

The light transmission layer 12 of the wavelength filter layer 11 can be formed by a method using a die roll or a method by hot melt extrusion.
In the method using a mold roll, a mold roll is prepared in which irregularities capable of transferring the unit light transmission convex portions 14a of the light transmission layer 12 are provided on the outer peripheral surface of a cylindrical roll. And the base material used as the base material part 13 is inserted between a die roll and the nip roll arrange | positioned so as to oppose this. At this time, the mold roll and the nip roll are rotated while supplying the light transmitting uneven portion constituting composition between the substrate and the mold roll. As a result, the light-transmitting uneven portion constituent composition is filled in the uneven portions formed on the surface of the mold roll, and the composition conforms to the uneven surface shape of the mold roll.

  Here, as the light transmitting uneven portion constituting composition, the above-described one is preferable, but more specifically, as follows. That is, the photocurable resin composition which mix | blended the reactive dilution monomer (M1) and the photoinitiator (I1) with the photocurable prepolymer (P1) can be used.

  Examples of the photocurable prepolymer (P1) include epoxy acrylate-based, urethane acrylate-based, polyether acrylate-based, polyester acrylate-based, and polythiol-based prepolymers.

  Examples of the reactive dilution monomer (M1) include vinyl pyrrolidone, 2-ethylhexyl acrylate, β-hydroxy acrylate, and tetrahydrofurfuryl acrylate.

  Examples of the photopolymerization initiator (I1) include hydroxybenzoyl compounds (2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, benzoin alkyl ether, etc.), benzoyl Formate compounds (such as methylbenzoylformate), thioxanthone compounds (such as isopropylthioxanthone), benzophenones (such as benzophenone), phosphate compounds (1,3,5-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-) Trimethylbenzoyl) -phenylphosphine oxide and the like, and benzyldimethyl ketal and the like. Among these, the irradiation device for curing the photocurable resin composition and the curability of the photocurable resin composition can be arbitrarily selected. From the viewpoint of preventing coloring of the light-transmitting uneven portion 14, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone and bis (2,4,6-trimethyl) are preferable. Benzoyl) -phenylphosphine oxide.

  These photocurable prepolymer (P1), reactive diluent monomer (M1) and photopolymerization initiator (I1) can be used alone or in combination of two or more.

  Light is irradiated from the substrate side to the light transmitting uneven portion constituting composition sandwiched between the mold roll and the substrate and filled therein by a light irradiation device. Thereby, a composition can be hardened and the shape can be fixed. And a base material part and the shape | molded light transmission uneven | corrugated | grooved part are released from a metal mold | die roll with a mold release roll.

  On the other hand, the hot melt extrusion is as follows. That is, an extrusion die having a hole shape corresponding to the cross-sectional shape in the thickness direction of the light transmission layer 12 is prepared. Then, the light transmitting layer constituting composition melted by heat is pressurized using an extruder, passed through the holes of the extrusion mold, and cooled to obtain a long sheet whose cross-sectional shape is the shape of the light transmitting layer. be able to.

  A light absorption layer is laminated on the light transmission layer formed as described above. The method of laminating is not particularly limited, but a method of laminating a light-absorbing layer-constituting composition containing an adhesive on one surface of a release sheet and covering the light-transmitting layer with this composition, Examples thereof include a method of directly applying the absorbent layer constituting composition to the light transmission layer.

  As described above, the electromagnetic wave shielding layer 18 may be formed by laminating the conductor mesh layer 18a on the surface of the base material portion 13 of the light transmission layer 12 on the surface opposite to the light transmission uneven portion 14.

  The hard coat layer 19 can be formed by applying the hard coat composition as described above before curing from the formed conductor mesh layer 18a, and then curing the composition.

  According to such a manufacturing method, a wavelength filter layer and an optical sheet provided with the same can be efficiently manufactured.

  In addition to the above-described layers, the optical sheet 10 may be laminated with a layer having other functions using an adhesive or the like. Examples of other layers include a near infrared absorbing layer, an ultraviolet absorbing layer, an antireflection layer, and an antiglare layer. Each layer will be described below.

  The near-infrared absorbing layer has a function of absorbing near-infrared light generated due to xenon gas discharge emitted by the PDP. For the near infrared absorbing layer, a commercially available film having a known near infrared absorbing agent is used, or a composition containing a near infrared absorbing dye in the adhesive layer or the resin layer is formed, or this is used as a transparent substrate or others. It can apply | coat on this functional filter, and what was formed through drying, the hardening process, etc. as needed can be used.

As the near-infrared absorbing dye, a near-infrared region generated due to the xenon gas discharge emitted from the PDP, that is, a pigment that absorbs a wavelength region of 800 nm to 1100 nm is used. The near infrared transmittance in the wavelength region is preferably 20% or less, and more preferably 10% or less.
At the same time, it is desirable that the near-infrared absorbing layer has sufficient transmittance in the visible light region, that is, in the wavelength region of 380 nm to 780 nm.

  The ultraviolet absorbing layer is a layer containing a pressure sensitive adhesive, a layer containing a resin, a yellowing of a transparent organic material such as a base material layer, and coloring such as a near infrared absorbing dye, a neon absorbing dye, and a toning dye. It is a layer provided to prevent material deterioration and has a function of absorbing ultraviolet rays. Therefore, it is preferable to arrange | position on the observation side rather than an adhesive layer. A well-known thing can be used as a ultraviolet absorption layer.

The antireflection layer is a layer for reducing reflection of a background due to specular reflection of external light on the display device surface, whitening of an image, and reduction in contrast. The antireflection layer is formed by alternately laminating a material having a high refractive index and a material having a low refractive index so that the outermost surface is a layer having a low refractive index, and cancels reflected light at each layer interface by interference. Thereby, reflection of the surface can be suppressed and a good antireflection effect can be obtained. This antireflection layer is usually formed by a vapor phase method or the like in which a low refractive index material typified by MgF ₂ or SiO ₂ and a high refractive index material such as TiO ₂ or ZrO ₂ are alternately deposited by vapor deposition or the like. Is done. In addition, from the viewpoint of providing the antireflection layer with an ultraviolet shielding function, an ultraviolet absorber may be contained in the antireflection layer.

  The antiglare layer is a layer that scatters or diffuses light like a frosted glass to blur a background image due to external light. Therefore, the antiglare layer has a configuration in which the light incident surface is roughened. In the treatment for roughening, a method of directly roughing the surface of the substrate by forming fine irregularities by sandblasting or embossing, an inorganic filler such as silica, or an organic filler such as resin particles was included. Examples thereof include a method of forming a rough surface with a coating film and a method of forming a porous film having a sea-island structure on the surface of the substrate.

  The optical paths of the image light and the external light in such a display device 1 including the optical sheet 10 will be described. In FIG. 4, the figure which expanded a part of wavelength filter layer 11 was shown, and the optical path examples L1-L7 in this part were shown by the arrow. However, the optical path is conceptually shown for explanation.

  The video lights L1 to L5 exit from the PDP 5 and enter the light absorption layer 15. The image lights L1 to L5 incident on the light absorbing layer 15 pass through the base 16 of the light absorbing layer 15 and one unit light absorbing convex portion 17a of the light absorbing uneven portion 17, and the unit light transmitting convex portion of the light transmitting layer 12. It is incident on 14a and finally provided to the viewer side.

  At this time, since the unit light absorption convex portion 17a and the unit light transmitting convex portion 14a have the same refractive index, the image lights L1 to L5 travel straight without being refracted at the interface. Further, the image lights L1 to L5 are transmitted through the light absorption layer 15 with different thicknesses. Therefore, as described above, the light absorption layer transmits through the light absorption layer with a higher transmittance than when the light absorption layer has a uniform thickness. Thereby, the front luminance can be increased as compared with the prior art.

  On the other hand, the external lights L6 and L7 are transmitted through the light transmission layer 12 at a predetermined angle with respect to the front from the observer side, enter the light absorption layer 15, and are attenuated here. At this time, the external light L6 and L7 also travel straight without being refracted at the interface because the unit light absorbing convex portion 17a and the unit light transmitting convex portion 14a have the same refractive index. In addition, since the absorbance is proportional to the absorption thickness and the external light is incident from an oblique direction, the absorption distance of the external light is generally close to the light absorption layer having a uniform thickness compared to the image light. For this reason, external light is absorbed to a greater extent than image light, and a reduction in contrast can be suppressed. In this embodiment, the effect is particularly high with respect to external light from obliquely above.

As described above, it is possible to suppress the same contrast decrease while increasing the front luminance as compared with the light absorption layer having a uniform thickness.
On the other hand, the optical sheet 10 provided in the display device 1 is not a complicated structure as in Patent Document 2 and Patent Document 3 described above, and its manufacture is easy, so that an optical sheet can be easily provided at low cost. it can.
That is, it is possible to provide a display device with good optical characteristics while being simple and low cost.
And from the viewpoint that there is generally more external light from above than external light from below, in this embodiment, external light from above is more easily absorbed.

FIG. 5 is a diagram showing a cross section of the video source unit 24 in the display device according to the second embodiment, schematically showing the layer structure, and corresponds to FIG. The image source unit 24 also includes the PDP 5 and the optical sheet 30 in the same manner as the image source unit 4 described above.
The optical sheet 30 includes a wavelength filter layer 31, an electromagnetic wave shielding layer 38, and a hard coat layer 19. In the present embodiment, components other than the wavelength filter layer 31 and the electromagnetic wave shielding layer 38 are common to the display device 1 of the first embodiment described above. Therefore, here, the wavelength filter layer 31 and the electromagnetic wave shielding layer 38 will be described. FIG. 6 shows an enlarged view of a part of the wavelength filter layer 31.

  The wavelength filter layer 31 includes a light transmission layer 32 and a light absorption layer 35, which are stacked in the thickness direction of the optical sheet 30. Details are as follows. In addition, in this embodiment, since the material which can be taken in order to comprise each layer and each site | part is common with the wavelength filter layer 11 with which the display apparatus 1 of 1st embodiment mentioned above is provided, description is abbreviate | omitted here. .

  The light transmission layer 32 is a layer that transmits light and forms an uneven surface at the interface with the light absorption layer 35. As shown in FIGS. 5 and 6, the light transmission layer 32 includes a base material portion 33 and a light transmission uneven portion 34, and the light transmission uneven portion 34 is provided with a plurality of unit light transmission convex portions 34 a. It has been.

  The base material portion 33 has a light transmitting property and serves as a base material for the light transmitting uneven portion 34 and supports the light transmitting uneven portion 34 so as to prevent deformation.

  The light transmission uneven portion 34 is a portion provided with a plurality of unit light transmission convex portions 34a having translucency. Each unit light transmission convex part 34a is formed so as to protrude toward the light absorbing layer 35 side. In this embodiment, the cross section has a portion that is substantially triangular, and includes a first surface 34b and a second surface 34c that form the hypotenuse. The unit light transmission convex portions 34a are formed so as to have the cross section shown in FIG. 5 and extend in the back / front direction of the paper, and are arranged in parallel in a direction orthogonal to the extending direction.

Specifically, as shown in FIG. 6, the angle formed by the first surface 34 b and the PDP side sheet surface normal of the optical sheet 30 is θ ₃ , and the second surface 34 c is the PDP side sheet surface normal of the optical sheet 30. when the angular theta ₄ formed between the, in the present embodiment is θ _{4 <θ 3.}

Specific angles of θ ₃ and θ ₄ are not limited, but θ ₃ is preferably 20 degrees or more and 40 degrees or less, and more preferably 25 degrees or more and 35 degrees or less. For example, θ ₃ can be obtained as follows. That is, in the case where the light absorbing layer 35 is manufactured by including an acrylic adhesive having a refractive index of 1.49, considering the external light incident on the optical sheet from an oblique angle of 45 degrees above, the external light is horizontal according to Snell's law. Accordingly, θ ₃ can also be set to 28.3 degrees corresponding to this, since the light-absorbing concavo-convex portion 37 travels downward from 28.3 degrees.

On the other hand, theta _4, like the theta _3, from the viewpoint of more effectively absorb external light from the ceiling direction in the room, preferably 0 ° ≦ θ _{4 <θ 3,} more preferably from 0 ° . In general, the amount of external light is higher from the upper side than the lower side. Therefore, if the relationship of θ ₄ <θ ₃ is satisfied, the efficiency of absorbing the external light is better.

  The pitch of the unit light transmission convex portions 34a is preferably 10 μm or more and 50 μm or less from the viewpoint of workability and the formation of the light absorption layer 35 described later. For the same reason, the protruding height of the unit light transmitting convex portion 34a is preferably 20 μm or more and 100 μm or less.

The light absorption layer 35 is a layer having a wavelength filter function that is combined with the light transmission layer 32 described above. In the present embodiment, the light absorption layer 35 includes an adhesive, and also has a function as an adhesive layer that appropriately adheres the optical sheet 30 to the transparent substrate 38b of the electromagnetic wave shielding layer 38.
In the present embodiment, the light absorption layer 35 has a function as a pressure-sensitive adhesive layer, but this is not necessarily required, and the pressure-sensitive adhesive layer may be provided separately. However, since the light absorbing layer 35 also has a function as an adhesive layer, there is an advantage that the layer configuration can be simplified efficiently. From this point of view, in the present embodiment, the light absorption layer 35 is a layer having an adhesive function.

  Therefore, the light absorption layer 35 has an adhesive and a light absorbing means contained in the adhesive. The light absorbing means is a means that exhibits a wavelength filter function having a light absorbing action such as one or more kinds of light absorbing agents and light absorbing dyes that can absorb light in a desired wavelength region.

  As can be seen from FIGS. 5 and 6, the light absorption layer 35 is laminated on the surface of the light transmission layer 32 on the side where the light transmission uneven portion 34 is provided. As a result, a part of the light absorption layer 35 enters between the unit light transmission convex portions 34a to form a unit light absorption convex portion 37a. Thereby, the light absorption layer 35 is formed so as to protrude to the light transmission layer 32 side of the base portion 36 having a constant thickness, and the light absorption uneven portion including a plurality of unit light absorption convex portions 37a. 37. 5 and 6, the light transmission uneven portion 34 and the light absorption uneven portion 37 are formed so as to fill the unevenness. Accordingly, the first surface 37b of the unit light absorbing convex portion 37 is formed so as to overlap with the first surface 34b of the unit light transmitting convex portion 34a, and similarly, the second surface 37c is formed so as to overlap with the second surface 34c. .

  The formed light absorption layer 35 has the same refractive index as that of at least the unit light transmission convex portion 34 a in the light transmission layer 32.

  Here, in the present embodiment, the light absorption layer 35 includes a base portion 36 and a light absorption uneven portion 37. As described above with reference to FIG. 7, it is the portion having the unevenness that contributes to the improvement of the transmittance, and the light absorption uneven portion 37 in the present embodiment. Therefore, the base portion 36 may be as thin as possible, and the light absorption layer may be formed only by the light absorption uneven portion without the base portion. In the present embodiment, the base 36 is provided from the viewpoint that the light absorption layer 35 has a function as an adhesive layer and from the viewpoint of productivity.

  Returning to FIG. 5, the electromagnetic wave shielding layer 38 will be described. In the present embodiment, the electromagnetic wave shielding layer 38 is formed by laminating a conductor mesh layer 38a on the surface of the transparent substrate 38b. As such an electromagnetic wave shielding layer 38, a known one can be used.

  The optical sheet 30 having such a configuration is disposed on the PDP 5 to form the video source unit 24. Specifically, as can be seen from FIG. 5, the light transmission layer 32 is directed to the PDP 5 side, and the optical sheet 30 is directly laminated on the PDP 5 with an adhesive (not shown). At this time, in this embodiment, in the unit light transmission convex part 34a of the light transmission layer 34, it arrange | positions so that the 1st surface 34b may become upper and the 2nd surface 34c may become lower. Accordingly, the unit light transmitting convex part 34a and the unit light absorbing convex part 37a are arranged in parallel in the vertical direction with the horizontal direction as the longitudinal direction.

  That is, in the display device of this embodiment, the optical sheet 30 is laminated on the viewer side surface of the PDP 5 in the video source unit 24. In the present embodiment, the PDP 5 and the optical sheet 30 are adhered by an adhesive (not shown). Furthermore, in the optical sheet 30, the light transmission layer 32 is laminated most on the PDP 5 side, and the light absorption layer 35 is laminated on the observer side. The light absorbing layer 35 has an adhesive function, and a transparent substrate 38b of the electromagnetic wave shielding layer 38 is laminated thereon. A conductor mesh layer 38a is laminated on the observer side of the transparent substrate 38b, and a hard coat layer 19 is laminated on the observer side.

  Even with such a display device, the same effect as the display device 1 of the first embodiment described above can be obtained.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

<Example 1>
In Example 1, an optical sheet was produced as follows.

(1) Production of mold roll A mold roll used for production of a light transmission layer was produced. The mold roll was cylindrical and was plated with copper, and the copper-plated portion was cut with a cutting tool (cutting tool) to form a groove corresponding to the unit light transmission convex portion of the light transmission layer. A diamond tool was used as the tool. When viewed from the rake face, the cutting tool has a shape in which the tip has two hypotenuses and one apex where it intersects, one slope angle is 0 degree with respect to the radial direction of the cylindrical shape of the roll, and the other hypotenuse angle is It was set to 28.3 degrees.
Using such a diamond tool, the groove pitch in the roll axis direction was 10 μm and the outer periphery of the copper plating layer of the mold roll was cut to form a groove. The pitch was 10 μm, the depth was 18.5 μm, and the slope angle was Grooves of 0 degrees and 28.3 degrees were formed with respect to the roll radial direction. The cut roll was chrome plated.

(2) Adjustment of Unit Light Transmitting Convex Constituent Composition 10.0 parts by mass, reactivity of photocurable prepolymer (P1) comprising polyester diol / tolylene diisocyanate / 2-hydroxyethyl acrylate = 85: 10: 5 30.0 parts by mass of phenoxyethyl acrylate as dilution monomer (M1), 30.0 parts by mass of bisphenol A polyethoxyethoxy acrylate, 30.0 parts by mass of tripropylene glycol diacrylate, mold release agent (S1) 0.05 part by mass of a tetradecanol-ethylene oxide 10-mole adduct as a monoester / diester = molar ratio 1/1, and 1-hydrokexicyclohexyl as a photopolymerization initiator (I1) Phenyl-ketone (Product name: Irgacure 184, Ciba Specialtyke) The Karuzu Co., Ltd.) was used 3.0 parts by weight.
These photocurable prepolymer (P1), reactive diluent monomer (M1), mold release agent (S1), and photopolymerization initiator (I1) are mixed and homogenized to form a unit light transmission convex part composition. Got. This composition was applied at a thickness of 100 μm, cured by irradiating with an ultraviolet ray of 800 mJ / cm ² with a high pressure mercury lamp, and measured for a refractive index of 589 nm using a multiwavelength Abbe refractometer DR-M4 (Atago). 1.51.

(3) Formation of light-transmitting layer As a base material to be a base material part between the mold roll and the nip roll prepared in (1) above, an easily adhesive PET film (A4300, manufactured by Toyobo Co., Ltd., thickness) 100 μm) was inserted and conveyed. In accordance with the conveyance of this base material, the unit light transmitting convex part constituting composition obtained in the above (2) is supplied onto the base material from the supply device, and the base material and the mold are pressed by the pressing force between the mold roll and the nip roll. The composition was filled between the mold rolls. Thereafter, 800 mJ / cm ² of ultraviolet light was irradiated from the substrate side with a high-pressure mercury lamp to cure the unit light transmitting convex portion constituent composition, thereby forming a light transmitting layer. Thereafter, the light transmission layer was released from the mold roll with a peeling roll to produce a light transmission layer having a thickness of 140 μm.
Accordingly, θ _{1 in} FIG. 2 was 0 degree, θ ₂ was 28.3 degrees, a light transmission layer having unit light transmission convex portions with a pitch of 10 μm and a height of 18.5 μm was obtained.

(4) Adjustment of light absorption layer constituent composition Acrylic adhesive (pressure-sensitive adhesive “Olivein” BPS6271: trade name, solid content 27%, manufactured by Toyo Ink Mfg. Co., Ltd.) 99.7 parts by mass, and curing agent (BXX5627: trade name, manufactured by Toyo Ink Manufacturing Co., Ltd.) 0.3 parts by mass, as a near infrared absorber, phthalocyanine compound (IR12: trade name, manufactured by Nippon Shokubai Co., Ltd.) 0.05 parts by mass, phthalocyanine 0.02 part by mass of a system compound (IR14: trade name, manufactured by Nippon Shokubai Co., Ltd.) and 0.03 part by weight of a diimmonium compound (IRG-068: trade name, manufactured by Nippon Shokubai Co., Ltd.) were blended. Furthermore, 0.01 part by mass of a neon light absorbing compound (TAP2: trade name, Yamada Chemical Co., Ltd.) was blended. Furthermore, 4 parts by mass of CyasorbUV24 (manufactured by Cytec) as an ultraviolet absorber, 2 parts by mass of TINUVIN144 (manufactured by Ciba Specialty Chemicals) as a light stabilizer, and KAYASET (Nippon Kayaku Co., Ltd.) as a toning dye 0.29 parts by mass of manufactured product) and 0.05 part by mass of Kunipia D36 (manufactured by Kunimine Kogyo Co., Ltd.) as a layered clay mineral were mixed to obtain a mixture. The mixture was sufficiently stirred to produce a light absorbing layer constituting composition.

(5) Formation of light-absorbing layer Bottom of groove formed between unit light-transmitting convex portions of light-transmitting convex portions of the light-transmitting layer prepared in (3) with the light-absorbing layer constituting composition prepared in (4) To a thickness of 25.0 μm. Thereafter, it was dried at 100 ° C. for 2 minutes to form a coating film, and a 38 μm light-release mold release film (E7005, manufactured by Toyobo Co., Ltd.) was laminated on the coating film.
In addition, about this light absorption layer, it was 1.49 when the refractive index of 589 nm was measured using multiwavelength Abbe refractometer DR-M4 (made by Atago Co., Ltd.).

  Thus, an optical sheet having a wavelength filter layer as Example 1 was obtained. And the existing optical sheet was peeled from the plasma television (Panasonic Corporation VIERA TH-P50G2), and the optical sheet of the present Example was bonded instead. At the time of bonding, the light absorption layer was disposed on the image source side as shown in FIG.

<Example 2>
In Example 2, the amount of the toning dye was changed from 0.29 parts by mass to 0.30 parts by mass with respect to “Adjustment of the composition of the light absorption layer” in Example 1, and the composition of the light absorption layer was changed. I got a thing. Others are common to the first embodiment.
Thus, an optical sheet having a wavelength filter layer as Example 2 was obtained. And the existing optical sheet was peeled off from plasma television (Panasonic Corporation VIERA TH-P50G2), and the optical sheet of the present Example was bonded instead. At the time of bonding, the light absorption layer was disposed on the image source side as shown in FIG.

<Example 3>
In Example 3, when the optical sheet of Example 1 is bonded to a plasma television (VIERA TH-P50G2 manufactured by Panasonic Corporation), the optical sheet of Example 1 is turned upside down as shown in FIG. The light transmission layer is disposed on the image source side. That is, in FIG. 6, θ ₄ is 0 degree and θ ₃ is 28.3 degrees.

<Example 4>
In Example 4, when the optical sheet of Example 2 is bonded to a plasma television (VIERA TH-P50G2 manufactured by Panasonic Corporation), the optical sheet of Example 2 is turned upside down as shown in FIG. The light transmission layer is disposed on the image source side. That is, in FIG. 6, θ ₄ is 0 degree and θ ₃ is 28.3 degrees.

<Comparative Example 1>
In Comparative Example 1, the amount of the toning pigment was changed from 0.29 parts by mass to 0.10 parts by mass with respect to “Adjustment of the pressure-sensitive adhesive composition having a wavelength filter function” in Example 1, and the wavelength A pressure-sensitive adhesive composition having a filter function was obtained.
This pressure-sensitive adhesive composition was applied on a middle peelable release film (E7007, manufactured by Toyobo Co., Ltd.) having a thickness of 38 μm so as to have a thickness of 25 μm. Thereafter, it is dried at 100 ° C. for 2 minutes to form a coating film, and a 38 μm lightly peelable release film (E7005, manufactured by Toyobo Co., Ltd.) is laminated on this coating film to have a wavelength filter function with a uniform thickness. An adhesive layer was prepared.
And the existing optical filter was peeled from the plasma television (Panasonic Corporation VIERA TH-P50G2), and the optical sheet of this comparative example was bonded instead.

<Evaluation>
Evaluation was performed in the environment shown in FIG. FIG. 8 is a side view of the tested space, where the left-right direction of the paper is the width direction of the space, the vertical direction of the paper is the height direction of the space, and the back / front direction of the paper is the depth direction of the space. That is, the fluorescent lamp was arranged as shown in FIG. 8 on the ceiling of a space having a width of 12 m, a height of 3 m, and a depth of 10 m. The floor of the space and the ceiling on the wall are white. Further, in the depth direction of the space, fluorescent lamps are arranged in parallel in the depth direction. The plasma television was placed on the floor in the center in the depth direction at one end in the width direction of the space.
An illuminometer (Minolta (T-1H)) is installed on the observer side in the center of the plasma TV screen so that its light-receiving surface faces the front of the observer side, and in a fluorescent lamp environment where the value of the illuminometer is 600 lux The front white luminance and the front black luminance were measured. A luminance meter (Minolta (LS-110)) was installed at a distance of 2 m in the 0 degree direction from the center of the screen.
The front white luminance was measured by displaying an all white screen in the WHITE mode of the pattern generator (KENWOOD CG-935N). On the other hand, the front black luminance was measured by displaying the lattice pattern in the CROSS HATCH mode using the same pattern generator and measuring the black portion.
Then, when the front white luminance and the front black luminance of Comparative Example 1 were set to 100, the front white luminance and front black luminance of Examples 1 to 4 were expressed. Therefore, it means that the higher the front white luminance, the higher the front luminance, and the lower the front black luminance, the higher the contrast.

<Evaluation results>
The results are shown in Table 1.

  In each of Examples 1 to 4, the front white brightness was improved with respect to Comparative Example 1. And the contrast improvement was seen from the comparative example 1 from the result of the front black brightness | luminance at this time.

  Moreover, although the manufacturing process of the optical sheet produced in Examples 1 to 4 is more complicated than the sheet described in Comparative Example 1, it is simpler than the optical sheets disclosed in Patent Document 2 and Patent Document 3. Can be manufactured. Therefore, it is possible to easily obtain higher performance than the optical sheet as in Comparative Example 1 while suppressing an increase in cost.

1 Plasma TV (display device)
4 Plasma display panel (PDP / video source)
DESCRIPTION OF SYMBOLS 10 Optical sheet 11 Wavelength filter layer 12 Light transmissive layer 13 Base part 14 Light transmissive uneven | corrugated | grooved part 14a Unit light transmissive convex part 15 Light absorption layer 16 Base 17 Light absorption concavo-convex part 17a Unit light absorption convex part 18 Electromagnetic wave shielding layer 19 Hard coat layer

Claims (8)

A display device that provides an image to an observer,
An optical sheet having a plurality of layers arranged on the viewer side from the video source and capable of controlling the video light from the video source to be emitted to the viewer side,
The optical sheet includes a wavelength filter layer that attenuates and transmits at least part of the wavelength region of visible light,
The wavelength filter layer is
The optical sheet includes an adhesive for laminating and fixing the optical sheet to the image source, and includes means for performing a wavelength filter function capable of absorbing light in at least a part of the wavelength region of visible light and attenuating the light amount. A light absorbing layer;
A light transmission layer that is disposed on the viewer side of the light absorption layer and forms an interface with the light absorption layer and transmits light;
The light transmission layer is convex toward the light absorption layer side, and includes a plurality of unit light transmission convex portions arranged in a vertical direction.
The unit light transmission convex portion has an angle formed with the normal direction of the observer-side sheet surface of the optical sheet of θ ₁ , a first surface that becomes the upper surface side of the convex, and an observer-side sheet of the optical sheet An angle formed with the normal direction of the surface is θ ₂ , and the second surface is the lower surface side of the convex, and
The θ ₁ is smaller than the θ ₂ ,
The refractive index of the unit light transmission convex portion is the same as the refractive index of the light absorbing layer.
Display device. A display device that provides an image to an observer,
An optical sheet having a plurality of layers arranged on the viewer side from the video source and capable of controlling the video light from the video source to be emitted to the viewer side,
The optical sheet includes a wavelength filter layer that attenuates and transmits at least part of the wavelength region of visible light,
The wavelength filter layer is
A means for providing a wavelength filter function that includes an adhesive that fixes the wavelength filter layer on another layer and that absorbs light in at least a part of the wavelength region of visible light and attenuates the amount of light. A light absorption layer comprising,
A light transmission layer disposed on the image source side of the light absorption layer, forming an interface with the light absorption layer and transmitting light;
The light transmission layer is convex toward the light absorption layer side, and includes a plurality of unit light transmission convex portions arranged in a vertical direction.
The unit light transmitting convex portion has an angle formed with the normal direction of the image source side sheet surface of the optical sheet of θ ₃ , a first surface which is the upper surface side of the convex, and an image source side sheet of the optical sheet An angle formed with the normal direction of the surface is θ ₄ , and the second surface is the lower surface side of the convex, and
The θ ₄ is smaller than the θ ₃ ,
The refractive index of the unit light transmission convex portion is the same as the refractive index of the light absorbing layer.
Display device.   The display device according to claim 1, wherein at least one of an electromagnetic wave shielding layer and a hard coat layer is disposed on the viewer side of the wavelength filter layer.   The display device according to claim 1, wherein a conductor mesh layer having an electromagnetic wave shielding function is formed on the observer side of the wavelength filter layer. A method for producing an optical sheet included in the display device according to any one of claims 1 to 4,
Inserting a base material between a mold roll having a surface shape corresponding to the shape of the unit light transmission convex portion of the light transmission layer, and a nip roll,
An optical sheet comprising a step of filling the composition between the substrate and the mold roll, and irradiating the composition with ultraviolet rays to cure the composition to form the unit light transmission convex portion. Production method. A method for producing an optical sheet included in the display device according to any one of claims 1 to 4,
A composition having a hole corresponding to the cross-sectional shape of the light transmission layer is press-fitted with a composition melted by heating, and the composition flowing out of the mold hole is cooled to cool the light transmission layer. The manufacturing method of the optical sheet including the process to form. A method for producing an optical sheet included in the display device according to any one of claims 1 to 4,
The manufacturing method of the optical sheet including the process of apply | coating the composition which comprises the said light absorption layer to a peeling sheet, and laminating | stacking the said composition on the said light transmissive layer after that. A method for producing an optical sheet included in the display device according to any one of claims 1 to 4,
The manufacturing method of the optical sheet including the process of apply | coating the composition which comprises the said light absorption layer directly to the said light transmissive layer.

Images