JP5157378B2 - Optical sheet and display device including the optical sheet - Google Patents

Description

  The present invention relates to an optical sheet and a display device that are disposed closer to an observer than an image light source and can appropriately control image light and external light, and more specifically, function properly without peeling or the like even in a high temperature and high humidity environment. The present invention relates to an optical sheet excellent in weather resistance and a display device.

  In a display device such as a television using a plasma display panel (hereinafter sometimes referred to as “PDP”), an optical sheet is disposed on the viewer side of the PDP. This optical sheet has a role of providing a high-quality image to an observer. Therefore, the optical sheet is configured by laminating various functional sheets having respective functions.

  In the plurality of layers stacked in this way, as shown in Patent Documents 1 and 2, the prism portion is arranged in parallel in the direction along the sheet surface, and transmits the image light from the PDP, and in the direction along the sheet surface. There may be provided a light absorption unit that is arranged in parallel with a predetermined interval and that appropriately blocks or reflects image light and external light to improve contrast and suppress ghosts.

JP 2006-189867 A JP 2006-350324 A

  In general, in Patent Documents 1 and 2, and other conventional optical sheets, the prism portion and the light absorbing portion are not just films like other layers, but have a predetermined molded shape, Using a mold, molding is performed with a resin that is cured by light such as ultraviolet rays. However, such a resin is easily affected by humidity, and in particular, deformation due to high humidity is larger than that of other layers, which affects the prism portion and the light absorbing portion. Thereby, depending on the environment in which the optical sheet is placed, peeling may occur at the interface between the optical functional sheet layer and the PET base material layer.

  In view of such problems, it is an object of the present invention to provide an optical sheet and a display device excellent in weather resistance that can appropriately exhibit their functions without peeling or the like even in a high temperature and high humidity environment.

  The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.

The invention according to claim 1 is an optical sheet (10, 30, which is arranged on the viewer side from the image light source (2)) and includes a plurality of layers that emit light to the viewer side by controlling light from the image light source. 40, 50), and prism portions (12, 12,...) Arranged in parallel along the sheet surface so as to transmit light, and light absorbing portions (13, 13) arranged in parallel to absorb light between the prism portions. 13), and a pair of layered bodies (18, 20) which are formed so as to be larger in length and breadth than the optical function sheet layer and are sandwiched between the optical function sheet layers. The pair of layered bodies are disposed so as to sandwich the optical function sheet layer , and the pair of layered bodies are bonded only at a portion formed larger than the optical function sheet layer of the pair of layered bodies, 該接lamellar bodies wear portions optical function sheet To solve the above problems by providing an optical sheet in which the optical functional sheet layer by covering the end surface of the coat layer is characterized in that it is arranged so as to be surrounded by the pair of the layered body.

  Here, the “layered body” is a concept that means a member formed with a thin thickness with respect to a so-called vertical and horizontal size such as a plate shape, a sheet shape, a film shape, and a foil shape. In the pair of layered bodies, the material and function may be different or the same between one and the other.

  According to a second aspect of the present invention, at least one of the pair of layered bodies (18, 20) in the optical sheet (10, 30, 40) according to the first aspect has a layer and a color tone having a function of blocking electromagnetic waves. It is selected from a correcting layer, a glass layer, a layer for preventing charging, a layer for blocking neon lines, a layer for blocking infrared rays, a layer for blocking ultraviolet rays, a layer for preventing reflection, and a layer having an antiglare function. Features.

  The invention according to claim 3 is characterized in that at least one of the pair of layered bodies in the optical sheet (50) according to claim 1 or 2 is formed of a layer (27) that hardly permeates moisture. .

  In the invention according to claim 4, each of the four sides of the pair of layered bodies (18, 20) in the optical sheet (10, 30, 40, 50) according to any one of claims 1 to 3, 10 mm or more is larger than an optical function sheet layer (11), It is characterized by the above-mentioned.

  The invention according to claim 5 is the optical sheet (10, 30, 40, 50) according to any one of claims 1 to 4, wherein the thickness of the optical function sheet layer (11) is 100 to 500 μm. It is characterized by being.

  The invention according to claim 6 is the optical sheet (10, 30, 40, 50) according to any one of claims 1 to 5, wherein the light absorbing portion (13, 13) of the optical function sheet layer (11) is provided. ,... Are configured to have a light absorption performance such that the transmittance is 40 to 70% in the transmittance measurement of a sheet having a thickness of 6 μm formed only of the material constituting the light absorbing portion. It is characterized by being.

  Here, the transmittance means a ratio of luminance before and after the measurement target sheet is arranged, and takes a maximum value of 100%.

  The invention according to claim 7 is the prism portion of the optical function sheet layer (11) in the sheet thickness direction cross section of the optical sheet (10, 30, 40, 50) according to any one of claims 1 to 6. (12, 12,...) Is a trapezoidal shape having a short upper base on one sheet surface side and a long lower base on the other sheet surface side, and the light absorbing portion (13, 13,...) Is one sheet surface. It is a triangle having a base on the side.

  The invention according to claim 8 is the optical function sheet layer (11 ″) in the sheet thickness direction cross section of the optical sheet (10, 30, 40, 50) according to any one of claims 1-6. The prism portion (12 ″, 12 ″) has a trapezoidal shape having a short upper base on one sheet surface side and a long lower bottom on the other sheet surface side, and the light absorbing portion (13 ″) It is a trapezoid having a long lower base on the sheet surface side and a short upper base on the other sheet surface side.

  The invention according to claim 9 is provided between the upper base and the lower base of the prism portion (12, 12,...) In the optical sheet (10, 30, 40, 50) according to claim 7 or 8. The hypotenuse of the trapezoid is characterized by being greater than 0 degree and less than 10 degrees with respect to the normal of the sheet surface.

  The invention according to claim 10 includes an upper base and a lower base of the prism portion (12, 12,...) In the optical sheet (10, 30, 40, 50) according to any one of claims 7 to 9. The hypotenuse of the trapezoid provided between the two is composed of a polygonal line or a curved line.

  Here, when the hypotenuse has a curved shape, the angle formed by the curve and the normal of the sheet surface is obtained as follows. The curve is divided into 10 equal parts in the sheet thickness direction, and the end points of the obtained curves are connected to obtain a straight line. And it is preferable that the angle | corner which each obtained straight line and the normal line of a sheet | seat surface make is more than 0 degree | times and below 10 degree | times.

  As for invention of Claim 11, the average particle diameter is 1 micrometer in the light absorption part (13, 13, ...) in the optical sheet (10, 30, 40, 50) as described in any one of Claims 1-10. It contains the above light absorbing particles.

  Here, “average particle size of 1 μm” in the case of “average particle size of 1 μm or more” is intended for particles having a particle size of 0.5 μm or more and smaller than 1.5 μm in the particle size measurement by the weight distribution method. In the particle size distribution, it means that the standard deviation is 0.3 or more.

  The invention according to claim 12 is that the refractive index of the material forming the prism portion in the optical sheet (10, 20, 30, 40) according to any one of claims 1 to 11 is Np, and the light absorption portion. When the refractive index of the material to be formed is Nb, the Np and Nb are values of 1.49 to 1.56.

  The invention according to claim 13 is characterized in that there is a relationship of Np ≧ Nb between Np and Nb in the optical sheet (10, 20, 30, 40) according to claim 12.

  According to a fourteenth aspect of the present invention, the prism portion and the light absorbing portion of the optical functional sheet layer in the optical sheet according to any one of the first to thirteenth aspects have a predetermined cross section and extend in the longitudinal direction. In addition, two optical function sheet layers are stacked, and the two optical function sheet layers are stacked so that the longitudinal directions of one and the other are perpendicular to each other.

  The invention according to claim 15 solves the above-mentioned problem by providing a display device (1, 1 ′) comprising the optical sheet according to any one of claims 1-14. .

  ADVANTAGE OF THE INVENTION According to this invention, durability in a high temperature, high humidity environment improves with respect to the conventional optical sheet, and an optical sheet with a weather resistance and a display apparatus provided with this optical sheet can be provided.

  Such an operation and gain of the present invention will be made clear from the best mode for carrying out the invention described below.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

  FIG. 1 shows a cross section of the optical sheet 10 of the present invention according to the first embodiment, and is a diagram schematically showing one end portion and a layer configuration. In FIG. 1, some repetitive symbols may be omitted for the sake of clarity (the same applies to the following drawings). 1 shows only one end, three other ends not shown in FIG. 1 are formed in the same manner. The optical sheet 10 includes an optical functional sheet layer 11, a PET film layer 16 as a base material layer, an adhesive layer 17, a toning film layer 18, an adhesive layer 19, an electromagnetic wave shielding film layer 20, an adhesive layer 21, and a glass layer. 22, an antistatic film layer 23 and an antireflection film layer 24 are provided. Each of the layers extends in the back / front direction of the paper while maintaining the cross section shown in FIG. Each layer will be described below.

  The optical functional sheet layer 11 includes prism sections 12, 12,... That are substantially trapezoidal in the sheet thickness direction cross section of the optical sheet 10, and light absorbing sections 13, 13,... Disposed between the prism sections 12, 12,. … And. FIG. 2 shows an enlarged view focusing on one light absorbing portion 13 and the prism portions 12 and 12 adjacent thereto. The optical function sheet layer 11 will be described with reference to FIGS. 1 and 2 and the drawings appropriately shown.

  The prism parts 12, 12,... Are elements having a substantially trapezoidal cross section having a long lower base on the PET film layer 16 side and a short upper base on the opposite side. The prism parts 12, 12,... Are made of a light transmissive resin having a refractive index of Np. This is usually formed of, for example, epoxy acrylate having a characteristic of being cured by ionizing radiation, ultraviolet rays or the like. The value of the refractive index Np is not particularly limited, but is preferably 1.49 to 1.56 from the viewpoint of the availability of the applied material. The image light is provided to the observer by transmitting the image light through the prism portions 12, 12,.

  The light absorbing parts 13, 13,... Are parts disposed between the prism parts 12, 12,. Therefore, the light absorbing portions 13, 13,... Have a substantially triangular shape with the upper base side of the prism portions 12, 12,... As the base side and the apex opposite thereto as the lower base side of the prism portions 12, 12,. Become. In addition, the light absorption parts 13, 13,... Include a binder part 14 filled with a substance having a refractive index of Nb, and light absorption particles 15, 15,. The external light is incident on and absorbed by the light absorbing portions 13, 13,.

  The binder material filled in the binder part 14 is made of a material having a refractive index Nb equal to or lower than the refractive index Np of the prism parts 12, 12,. The value of the refractive index Nb is not particularly limited, but is preferably 1.49 to 1.56 from the viewpoint of the availability of the applied material. The difference in refractive index between Np and Nb is not particularly limited, but is preferably 0 to 0.06. The material used as the binder material is not particularly limited, and examples thereof include urethane acrylate having characteristics of being cured by ionizing radiation, ultraviolet rays, and the like.

  Due to the relationship between the refractive index difference and the incident angle of the image light, a part of the image light can be reflected at the interface without entering the light absorbing portions 13, 13,... Therefore, it becomes possible to provide bright images.

  The light-absorbing particles 15, 15,... Are preferably particles having an average particle diameter of 1 μm or more from the viewpoint of availability and handleability, and this is a predetermined concentration with pigments such as carbon or dyes such as red, blue, and yellow. It is colored. For this, for example, commercially available colored resin fine particles can be used. The refractive index Nr of the light absorbing particles 15, 15,... Is not particularly limited.

  Here, the light absorption performance of the light absorbing portions 13, 13,... Can be adjusted as appropriate depending on the purpose. However, in the transmittance measurement of a sheet having a thickness of 6 μm formed only from the material constituting the light absorbing portion, It is preferable that the light absorption performance is such that the rate is 40 to 70%. The means for adjusting the transmittance to 40 to 70% is not particularly limited, and examples thereof include adjusting the content of light absorbing particles and light absorbing performance.

  Further, the angle θ of the oblique sides (two sides extending in the sheet thickness direction) of the light absorbing portions 13, 13,... With respect to the sheet surface normal line is not particularly limited. In many cases, from the viewpoint of reflection / absorption, it is preferably greater than 0 degree and 10 degrees or less, and more preferably greater than 0 degree and 6 degrees or less.

As shown in FIGS. 1 and 2, the shape of the optical function sheet layer 11 is such that the prism portions 12, 12,... Have a substantially trapezoidal cross section, and are formed between the light absorbing portions 13, 13, ... has a triangular cross-section. However, if the light can be controlled appropriately, these shapes are not particularly limited, and appropriate shapes are appropriately adopted. FIG. 3 shows a modification. FIG. 3 is a view corresponding to FIG. 2 and shows one light absorbing portion 13 ′ and prism portions 12 ′ and 12 ′ arranged on both sides thereof. As can be seen from FIG. 3, the hypotenuse in the cross section of the light absorbing portion 13 ′ (the hypotenuse of the prism portions 12 ′ and 12 ′) is not from one hypotenuse, but two oblique sides 13a ′, 13a ′, 13b ′, and 13b ′. It is composed of That is, the cross section has a polygonal oblique side. Specifically, the oblique sides 13a ′ and 13a ′ arranged on the upper base (short side bottom) side (left side of the paper surface) of the prism portions 12 ′ and 12 ′ have an angle θ ₁ with respect to the normal of the sheet surface of the optical sheet. Have. On the other hand, the oblique sides 13b ′ and 13b ′ arranged on the lower bottom (long side bottom) side (right side of the sheet) of the prism portions 12 ′ and 12 ′ have an angle θ ₂ with respect to the normal of the sheet surface of the optical sheet. doing.

It is preferable that the angles θ ₁ and θ ₂ have a relationship of θ ₁ > θ ₂ and both are in the range of greater than 0 degree and less than 10 degrees. A more preferable angle is greater than 0 degree and 6 degrees or less. Further, the two oblique sides 13a ', 13b' intersect at a position separated into _{T 1} and _{T 2} in the thickness direction of the optical functional sheet layer 11 (left-right direction). T ₁ and T ₂ are preferably the same size.

  The modification is an example constituted by two hypotenuses, but may be formed in a polygonal line shape in the cross section by comprising more hypotenuses. Furthermore, this may be curved.

  In the present embodiment, the case where the light absorbing portion is triangular has been described and described, but the shape of the light absorbing portion is not limited to this and may be trapezoidal. FIG. 4 shows the light absorbing portion 13 ″ of the optical functional sheet layer 11 ″ of the optical sheet 10 ″ and the prism portions 12 ″ and 12 ″ adjacent thereto in the example where the light absorbing portion is trapezoidal. . Here, as shown in FIG. 4, the light absorbing portion 13 '' has a trapezoidal shape. At this time, the long base (lower base) of the trapezoid is on the side opposite to the PET film layer (not shown) (the right side of the drawing), and the short base is short. Can be disposed on the PET film layer side (left side of the paper). Here, the length of the upper base indicated by E in FIG. 4 is preferably 2 to 25 μm.

  Each size of the optical sheet 10 indicated by B, C, and D in FIG. 1 can be appropriately changed according to the purpose and is not particularly limited, but in many cases, the pitch indicated by C is 50 to 150 μm. The range of is preferably applied. Moreover, the aperture ratio defined by (B / C) × 100% is preferably 50 to 90%, and the depth of the light absorbing portions 13, 13,... Shown in FIG.

  Returning to FIG. 1, another configuration of the optical sheet 10 will be described. The PET film layer 16 is a film layer serving as a base for forming the optical functional sheet layer 11 on the PET film layer 16 and is formed mainly of PET. The PET film layer 16 only needs to contain PET as a main component, and may contain other resins. Here, the main component means 50% by mass or more based on the whole PET film layer. Various additives may be added in appropriate amounts. Examples of general additives include phenol-based antioxidants, lactone-based stabilizers, and the like.

  The pressure-sensitive adhesive layer 17 is a layer in which a pressure-sensitive adhesive for adhering the optical function sheet layer 11 and the PET film layer 16 to other layers is disposed. The material of the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer 17 is not particularly limited as long as it transmits light and can be appropriately bonded to others. Examples thereof include an acrylic copolymer, and the adhesive strength thereof is, for example, about several N / 25 mm to 20 N / 25 mm.

  The optical function sheet layer 11 is manufactured as follows, for example. A liquid material serving as a material for the prism portion is applied to one surface side of the PET film layer 16. Next, the prism portions 12, 12,... Are formed by irradiating with ultraviolet rays in a state where the material to be the prism portion is sandwiched between the roll mold for forming the prism portion shape and the PET film. . Then, between the prism parts 12, 12,..., The liquid material in which black light-absorbing particles are added is filled in the transparent resin that is the material of the binder part, and the excess material is removed by squeegeeing, etc. Are cured by irradiating with ultraviolet rays to form the light absorbing portions 13, 13,. Thereby, the optical function sheet layer 11 is manufactured. The pressure-sensitive adhesive layer 17 is laminated on the optical function sheet layer 11 thus manufactured.

  The toning film layer 18 is a layer constituting one of a pair of layered bodies that seal and sandwich the optical function sheet layer 11 in the present embodiment. The toning film layer 18 is sometimes referred to as a Tint layer, and is a layer on which a film that corrects the color of the image light from the PDP and provides an image with a color suitable for the viewer is arranged. Moreover, you may be comprised so that a neon line may also be interrupted | blocked. This film contains dyes and pigments so that the desired color correction can be performed.

  The electromagnetic wave shielding film layer 20 is a layer constituting another one of the pair of layered bodies that seal and sandwich the optical function sheet layer 11 in the present embodiment. The electromagnetic wave shielding film layer 20 is a layer in which a film having translucency and having a role of shielding electromagnetic waves generated from the PDP is disposed. The type of the film is not particularly limited as long as it is such a film. Examples of the film that can be usually obtained include a metal mesh and a transparent conductive film.

  The glass layer 22 is a layer made of a transparent glass plate. In the optical sheet 10 of this embodiment, the optical sheet 10 is maintained flat by laminating each layer on the glass layer 22.

  The antistatic film layer 23 is a layer in which a film sometimes referred to as an antistatic (AS) film is disposed. This is a film that can prevent charging, that is, static electricity. A commonly available AS film can be applied to this.

  The antireflection film layer 24 is a layer in which a film sometimes called an anti-reflection film (AR) is arranged. This is a film in which external light or the like is incident on the screen, which is reflected on the screen to the observer side to reduce contrast or prevent reflection on the screen. For this, it is possible to use an AR film that is usually available.

  As an alternative to the antireflection film layer 24, an antiglare film layer may be disposed here. The antiglare film layer is a layer in which a film sometimes referred to as an antiglare (AG) film is disposed. This is a film that can prevent glare when an observer looks at the screen. As the antiglare film, it is possible to apply an AG film that is usually available.

  Here, each of the antistatic film layer 23 and the antireflection film layer 24 has a pressure-sensitive adhesive layer for adhesion to other layers, but the illustration in the figure is omitted for easy viewing of the figure. .

  The pressure-sensitive adhesive layers 19 and 21 are layers in which a pressure-sensitive adhesive for laminating and sticking the layers together is disposed. The material of the pressure-sensitive adhesive used for the pressure-sensitive adhesive layers 19 and 21 is not particularly limited as long as it transmits light and can appropriately bond the layers together. Examples thereof include an acrylic copolymer, and the adhesive strength thereof is, for example, about several N / 25 mm to 20 N / 25 mm.

  The optical sheet 10 having each layer as described above further has the following characteristics. That is, in the optical sheet 10, the optical function sheet layer 11, the PET film layer 16, and the pressure-sensitive adhesive layer 17 laminated thereon are formed smaller in length and breadth than any other layer, and the other layers have the height and breadth. It has been enlarged. Then, the optical function sheet layer 11, the PET film layer 16, and the pressure-sensitive adhesive layer 17 that are formed to be small are arranged between other layers that are formed to be larger than this. Specifically, in this embodiment, the optical function sheet layer 11, the PET film layer 16, and the pressure-sensitive adhesive layer 17 are disposed between the toning film layer 18 and the electromagnetic wave shielding film layer 20. The degree of reduction indicated by A in FIG. 1 is not particularly limited, but the size of A is preferably 5 mm or more from the viewpoint of covering an appropriate end as described later. The upper limit of the distance A is not particularly limited as long as it does not affect the video.

  Furthermore, as shown in FIG. 1, the end part of the toning film layer 18 arrange | positioned at the one surface side of the optical function sheet layer 11, and the adhesive layer 19 with which this is equipped is the optical function sheet layer 11 The PET film layer 16 and the pressure-sensitive adhesive layer 17 are adhered to the electromagnetic wave shielding film layer 20 so as to cover the end portions and the end surfaces thereof. Thus, the optical function sheet layer 11, the PET film layer 16, and the pressure-sensitive adhesive layer 17 are sandwiched between the toning film layer 18 and the electromagnetic wave shielding film layer 20, and are configured to be sealed between them. The Therefore, the influence of humidity on the optical function sheet layer 11, the PET film layer 16, and the pressure-sensitive adhesive layer 17 can be reduced. Thereby, for example, it is possible to prevent the optical function sheet layer 11 and the PET film layer 16 from peeling even in a high temperature and high humidity environment. Further, since the optical function sheet layer 11 is held between the two layers, the optical function sheet layer 11 can be stably held over a long period of time.

  FIG. 5 is a cross-sectional view of the optical sheet 30 of the present invention according to the second embodiment, schematically showing the layer configuration. In the optical sheet 30, one optical functional sheet layer 31 is disposed between the optical functional sheet layer 11 and the PET film layer 16 of the optical sheet 10 of the first embodiment. At this time, the prism portion 32 and the light absorbing portion (not shown in the figure) are arranged so as to be orthogonal to the prism portions 12, 12,... And the light absorbing portions 13, 13,. Therefore, the prism portions 32 and the light absorbing portions of the optical function sheet layer 31 are alternately arranged in parallel in the back / front direction of the paper.

  FIG. 6 is a cross-sectional view of the optical sheet 40 of the present invention according to the third embodiment, schematically showing the layer configuration. The optical sheet 40 is not provided with the glass layer 22 disposed on the optical sheet 10 of the first embodiment, and the adhesive layer 17 is disposed on the wide bottom side of the light absorbing portion 13 of the optical function sheet 11. ing. Therefore, the optical function sheet layer 11 and the PET film layer 16 are bonded to the electromagnetic wave shielding film layer 20 through this. Moreover, the toning film layer 18 which has the adhesive layers 19 and 21 on both surfaces is arrange | positioned in the surface on the opposite side to the surface where the optical function sheet layer 11 is arrange | positioned among the surfaces of the PET film layer 16. Further, the PET film layer 16 is directly laminated on the pressure-sensitive adhesive layer 21 side of the toning film layer 18, and the antistatic film layer 23 and the antireflection film layer 24 are directly laminated on the pressure-sensitive adhesive layer 19 side. Further, a pressure-sensitive adhesive layer 26 is further disposed on the surface of the electromagnetic wave shielding film layer 20 opposite to the pressure-sensitive adhesive layer 17. With this configuration, the optical sheet 40 can be directly attached to the PDP 2 (see FIG. 9) as will be described later.

FIG. 7 is a cross-sectional view of the optical sheet 50 of the present invention according to the fourth embodiment, schematically showing the layer configuration. The optical sheet 50 is an example in which the moisture-proof film layer 27 and the pressure-sensitive adhesive layer 28 are disposed at the positions where the toning film layer 18 and the pressure-sensitive adhesive layer 19 are disposed in the optical sheet 10 of the first embodiment. The other layers are the same as the description of the optical sheet 10 and will not be described. The toning film layer 18 is laminated between the electromagnetic wave shielding film layer 20 and the glass layer 22.
The moisture-proof film layer 27 is a layer in which films having waterproof and moisture-proof functions are laminated. The moisture-proof film layer 27 has no so-called optical function. However, for example, if it is necessary to dispose all the film layers having optical functions on one side of the optical function sheet layer 11, the moisture-proof film layer 27 can be provided on the other side of the optical function sheet layer 11. The above-described effects of the invention are obtained.

  The film provided in the moisture-proof film layer 27 is not particularly limited as long as it has a waterproof and moisture-proof function, but PET deposited with aluminum oxide or silica can be preferably used.

  In the optical sheets 10, 30, 40, and 50 described so far, the order in which the layers are laminated and the type of layers employed are not particularly limited as long as they have the characteristics of the present invention. For example, an arrangement in which the toning film layer and the electromagnetic wave shielding film layer are interchanged, an arrangement in which another layer is laminated on the toning film layer side, and the like can be given. In addition to the film layer having the above function, a film layer that blocks neon wires, a film layer that blocks infrared rays, a layer that blocks ultraviolet rays, and the like may be laminated. Furthermore, a film having two functions may be used in one film, and for example, one film having AR and AS functions may be mentioned.

  In addition, in the optical function sheet layer 11 of the optical sheets 10, 30, 40, and 50, the light absorbing portion can absorb light by including light absorbing particles in the binder portion. However, the light absorbing portion is not necessarily required to have the above configuration as long as it can absorb light. For example, the entire light absorbing portion may be filled with black or other colored photocurable resin. This also makes it possible to obtain the optical sheet of the present invention. In this case, after forming the prism portion as described above, the light absorbing portion can be formed by filling the portion that becomes the light absorbing portion with the resin and irradiating ultraviolet rays or the like.

  Further, the base material layer is not necessarily made of PET, and “polyester resin” such as polybutylene terephthalate resin (PBT) or polytrimethylene terephthalate resin (PTT) can be used. . In the present embodiment, it has been described that a resin having PET as a main component is a preferable material from the viewpoint of mass productivity, price, availability, etc. in addition to performance.

  The optical sheet 10 having such a configuration is manufactured as follows, for example. The PET film layer 16 in which the electromagnetic wave shielding film layer 20 and the optical function sheet layer 11 are laminated on one surface side of the glass plate to be the glass layer 22 is bonded one by one with each sheet. Then, the film to be the toning film layer 18 is bonded to the optical function sheet layer 11 so that the outer periphery protrudes in the same manner. The edge part of the optical function sheet | seat layer 11 is closed by the said bonding.

  Next, a configuration when the optical sheets 10 and 40 according to the present invention as described above are attached to the plasma televisions 1 and 1 ′ which are display devices will be described. 8 and 9, the optical sheets 10 and 40 are disposed on the image output side of the PDP 2, and the PDP 2 and the optical sheet 10 when the PDP 2 and the optical sheet 10 are provided in the plasma televisions 1 and 1 ′ are disposed. It is the figure which showed the layer structure of the part typically. 8 and 9, the right side of the drawing is the observer side.

  The display device 1 is a so-called glass filter type plasma television 1, and as shown in FIG. 8, the optical sheet 10 of the present invention is arranged with a gap indicated by F from PDP2 as an image source.

  The display device 1 ′ is a so-called direct bonding type plasma television 1 ′. As shown in FIG. 9, the optical sheet 40 of the present invention is directly laminated on the image emission surface of the PDP 2 that is an image source. At this time, the optical sheet 40 is stuck to the PDP 2 by the pressure-sensitive adhesive layer 26.

  Examples of the optical sheet having the above configuration will be described below in more detail. However, the present invention is not limited to the scope of the examples.

  In the examples, environmental tests were performed, and the adhesion (peeling) of the optical sheet of the present invention and the optical sheet of the comparative example was evaluated. This will be specifically described below.

<Test sample>
The sample used in the examples has a long side of 1130 mm and a short side of 640 mm, and is composed of three layers (acrylic adhesive layer J1: thickness 25 μm, PET film layer J2: thickness 125 μm, optical function sheet) Layer J3: 130 μm thick) was sandwiched between an electromagnetic shielding layer J4 (with adhesive layer J5) having a long side of 1140 mm and a short side of 650 mm and a PET film J6 having a thickness of 100 μm, and the ends were sealed (see FIG. 10). ).
On the other hand, the sample used for the comparative example had the same layer configuration, and the outer size of all layers was configured with a long side of 1130 mm and a short side of 640 mm. As a result, the optical function sheet layer, the acrylic pressure-sensitive adhesive layer, and the PET film layer are exposed on the end face of the sample.

<Conditions>
An environmental test was performed by placing the above-described optical sheet of the present invention and the optical sheet of the comparative example under the following conditions using a high-temperature and high-humidity machine.
-Condition 1: Temperature 60 ° C, Humidity 90%, 1000 hours-Condition 2: Temperature 80 ° C, Humidity 95%, 1000 hours

<Evaluation>
For evaluation, a sample was taken out from a high-temperature and high-humidity machine and allowed to stand at room temperature for 24 hours, and then the state of the outer periphery was visually confirmed. Table 1 shows the results.

  As can be seen from Table 1, in the comparative example, peeling was observed on the outer peripheral portion of the optical sheet in the case of Condition 2, but the optical sheet of the present invention did not peel in any condition, and the adhesion was good. It was.

  Although the present invention has been described in connection with the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed herein, The invention can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and an optical sheet and a display device accompanied by such a change are also included in the technical scope of the present invention. Must be understood.

It is the figure which showed the cross section of the optical sheet of this invention concerning 1st embodiment, and represented the layer structure typically. It is the figure which expanded and showed a part of optical sheet shown in FIG. It is the figure which expanded and showed a part of optical sheet of this invention concerning a modification. It is the figure which expanded and showed a part of optical sheet of this invention concerning the example whose light absorption part is trapezoid. It is the figure which showed the cross section of the optical sheet of this invention concerning 2nd embodiment, and represented the layer structure typically. It is the figure which showed the cross section of the optical sheet of this invention concerning 3rd embodiment, and represented the layer structure typically. It is the figure which showed the cross section of the optical sheet of this invention concerning 4th embodiment, and represented the layer structure typically. It is the figure which showed the layer structure of PDP and an optical sheet part in the scene where the optical sheet of this invention was attached to the plasma television of a glass filter system. It is the figure which showed the layer structure of PDP and an optical sheet part in the scene where the optical sheet of this invention was attached to the plasma television of a direct bonding system. It is the figure which showed typically the layer structure of the sample in an Example.

Explanation of symbols

1, 1 'Plasma TV (display device)
2 Plasma display panel (PDP, video light source)
10, 30, 40, 50 Optical sheet 11, 31 Optical function sheet layer 12, 32 Prism part 13 Light absorption part 14 Binder part 15 Light absorption particle 16 PET film layer (base material layer)
17 pressure-sensitive adhesive layer 18 toning film layer 19 pressure-sensitive adhesive layer 20 electromagnetic wave shielding film layer 21 pressure-sensitive adhesive layer 22 glass layer 23 antistatic film layer (AS)
24 Antireflection film layer (AR)
27 Moisture-proof film layer

Claims (15)

An optical sheet that is disposed on the viewer side from the video light source, and includes a plurality of layers that emit light to the viewer side by controlling light from the video light source,
An optical functional sheet layer having a prism portion arranged in parallel along the sheet surface so as to transmit light, and a light absorbing portion arranged in parallel so as to absorb light between the prism portions;
A pair of layered bodies that are formed so as to be larger in length and breadth than the optical function sheet layer and are stacked so as to sandwich the optical function sheet layer,
The pair of layered bodies are disposed so as to sandwich the optical function sheet layer , and the pair of layered bodies are bonded to each other only at a portion formed larger than the optical function sheet layer of the pair of layered bodies. The optical sheet is arranged such that the optical functional sheet layer is surrounded by the pair of layered bodies by covering the end face of the optical functional sheet layer with the layered body of the bonded portion .   At least one of the pair of layered bodies has a function of blocking electromagnetic waves, a layer for correcting color tone, a glass layer, a layer for preventing charging, a layer for blocking neon lines, a layer for blocking infrared rays, and a layer for blocking ultraviolet rays The optical sheet according to claim 1, wherein the optical sheet is selected from a layer for preventing reflection, a layer for preventing reflection, and a layer having an antiglare function.   The optical sheet according to claim 1, wherein at least one of the pair of layered bodies is formed of a layer that hardly transmits moisture.   4. The optical sheet according to claim 1, wherein each of the four sides of the pair of layered bodies is 10 mm or more larger than the optical function sheet layer. 5.   The optical sheet according to claim 1, wherein the optical function sheet layer has a thickness of 100 to 500 μm.   The light absorbing portion of the optical function sheet layer has a light absorbing performance such that the transmittance is 40 to 70% in the transmittance measurement of a sheet having a thickness of 6 μm formed only of the material constituting the light absorbing portion. It is comprised so that it may have. The optical sheet as described in any one of Claims 1-5 characterized by the above-mentioned. In the sheet thickness direction cross section,
The prism portion of the optical function sheet layer has a trapezoidal shape having a short upper base on one sheet surface side and a long lower base on the other sheet surface side,
The optical sheet according to any one of claims 1 to 6, wherein the light absorbing portion is a triangle having a base on the one sheet surface side. In the sheet thickness direction cross section,
The prism portion of the optical function sheet layer has a trapezoidal shape having a short upper base on one sheet surface side and a long lower base on the other sheet surface side,
7. The optical device according to claim 1, wherein the light absorbing portion is a trapezoid having a long lower base on the one sheet surface side and a short upper base on the other sheet surface side. Sheet.   9. The oblique side of the trapezoid provided between the upper base and the lower base of the prism portion is greater than 0 degree and less than or equal to 10 degrees with respect to the normal of the sheet surface. The optical sheet according to 1.   The optical sheet according to any one of claims 7 to 9, wherein a hypotenuse of the trapezoid formed between the upper base and the lower base of the prism portion is a polygonal line or a curved line. .   The optical sheet according to claim 1, wherein the light absorbing portion contains light absorbing particles having an average particle diameter of 1 μm or more.   When the refractive index of the material forming the prism portion is Np and the refractive index of the material forming the light absorption portion is Nb, the Np and Nb are values of 1.49 to 1.56. The optical sheet according to claim 1, wherein the optical sheet is characterized in that   The optical sheet according to claim 12, wherein a relationship of Np ≧ Nb exists between the Np and Nb.   The prism portion and the light absorbing portion of the optical function sheet layer are formed to have a predetermined cross section and extend in the longitudinal direction, and the two optical function sheet layers are laminated. The optical sheet according to any one of claims 1 to 13, wherein the functional sheet layer is laminated so that the longitudinal direction is perpendicular to one and the other.   A display device comprising the optical sheet according to claim 1.

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