JP2009294462A - Video source unit, optical sheet and video display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video source unit free from the generation of discoloration and having excellent light resistance, to provide an optical sheet, and to provide a video display device. <P>SOLUTION: The video source unit 10 includes: a video source 10a emitting an video by selfillumination or by being matched with the other light source; and an optical sheet 10b with a plurality of layers arranged at the side of an observer from the video source, controlling light from the video source and capable of emitting the light to the side of the observer. The optical sheet includes: an optical functional sheet layer 17 having prism parts 18 arranged along the sheet face so as to transmit light and formed by an ultraviolet curing resin; and light absorbing parts 19 arranged so as to absorb light among the prism parts; and a layer 23 arranged at the side opposite to the video source side of the optical function sheet layer and comprising an ultraviolet absorption agent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image source unit, an optical sheet, and an image display device for emitting an appropriate image from an image source to an observer, and more particularly to an image source unit, an optical sheet, and an image display device that are excellent in light resistance.

  For video display devices that emit images to the viewer, such as liquid crystal displays, plasma displays, rear projections, organic ELs, FEDs, etc., the video source and the quality of the video light from the video source can be improved for the viewer. And an optical sheet on which layers having various functions for emission are laminated.

For example, Patent Document 1 is disclosed as an example of the optical sheet. The optical sheet described in Patent Document 1 is disposed between a prism portion that transmits image light and the prism portion, and appropriately blocks or reflects image light and external light to improve contrast or suppress ghost. A light absorption part.
JP 2006-189867 A

  However, in the image source unit and the image display device including the optical sheet described in Patent Document 1 and the conventional optical sheet, discoloration may occur in members stacked on the optical sheet due to continued use.

  In view of the above problems, an object of the present invention is to provide an image source unit, an optical sheet, and an image display device that are excellent in light resistance without causing discoloration or the like.

  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 embodiments.

  As a result of intensive studies, the inventors have obtained the knowledge that among the layers provided in the image source unit, in particular, the ultraviolet curable resin is yellowed by the ultraviolet rays irradiated from outside. Based on this knowledge, the inventors have completed the following invention.

  According to the first aspect of the present invention, a video source (10a, 40a) that emits a self-luminous light or is combined with another light source and a viewer side of the video source are arranged, and light from the video source is provided. And an optical sheet (10b, 40b) having a plurality of layers that can be emitted to the observer side by controlling the image source unit (10, 30, 35, 40, 50, 55), Is arranged in parallel along the sheet surface so that light can be transmitted, and is made of an ultraviolet curable resin so that light can be absorbed between the prism parts (18, 26, 32, 37, 44, 52, 55). An optical function sheet layer (17, 25, 31, 36, 43, 51, 56) having light absorbers (19, 33a, 33b, 38a, 38b, 45, 53a, 53b, 58a, 58b) arranged in parallel; Image source of optical function sheet layer And is disposed on the opposite side, the layer containing the ultraviolet absorber (23,47), to solve the above problems by providing a video source unit comprising a.

  Here, “the prism parts are juxtaposed along the sheet surface” means that the prism parts are not limited to be juxtaposed along one direction of the sheet surface, and have a predetermined law property along the sheet surface. It is a good concept if they are arranged so as to be arranged. Therefore, for example, they may be arranged obliquely along the sheet surface, or may be arranged in a staggered manner.

  According to a second aspect of the present invention, in the image source unit (10, 30, 35) of the first aspect, the optical sheet (10b) has a TAC film layer (23) and contains an ultraviolet absorber. The layer is the TAC film layer.

  According to a third aspect of the present invention, in the video source unit according to the second aspect, the side surface opposite to the video source side of the TAC film layer is subjected to an anti-glare process.

  Here, the anti-glare treatment is synonymous with the anti-glare treatment.

  According to a fourth aspect of the present invention, in the image source unit (10, 30, 35) according to the second aspect, the optical sheet (10b) includes an antiglare film layer (24) and a TAC film layer (23) from the viewer side. ) And an adhesive layer (22) in this order.

  According to a fifth aspect of the present invention, the optical sheet (40b) of the video source unit (40) according to the first aspect has a color tone correction layer (47), and the layer containing the ultraviolet absorber is the color tone correction. It is a layer.

  According to a sixth aspect of the present invention, the optical sheet (40b) of the video source unit (40) according to the fifth aspect includes an anti-glare film layer (49) and a color tone correction layer (47) from the viewer side. Features.

  The invention according to claim 7 is the image source unit (10, 30, 35, 40, 50, 55) according to any one of claims 1 to 6, wherein the light absorbing portion (19, 33a, 33b, 38a, 38b, 45, 53a, 53b, 58a, 58b) are filled with a binder (20) made of resin, and light-absorbing particles (21) having an average particle diameter of 1 μm or more are dispersed in the binder. It is characterized by being.

  According to an eighth aspect of the present invention, the prism portion (18, 26) and the light absorption of the optical function sheet layer (17, 25) of the video source unit (10 ′) according to any one of the first to seventh aspects. The portion (19) is formed to extend in the longitudinal direction while maintaining a predetermined cross section, and two optical function sheet layers are laminated, and one of the two optical function sheet layers is an optical function sheet. The longitudinal direction of the light absorption part of the layer and the longitudinal direction of the light absorption part of the other optical function sheet layer of the two optical function sheet layers are laminated so as to have a predetermined angle. .

  The invention described in claim 9 is characterized in that the predetermined angle of the video source unit (10 ') described in claim 8 is 90 degrees.

  The invention according to claim 10 is the light of the optical function sheet layer (31, 36, 51, 56) of the image source unit (30, 35, 50, 55) according to any one of claims 1-7. The absorption parts (33a, 33b, 38a, 38b, 53a, 53b, 58a, 58b) are formed in a lattice shape that intersects at a predetermined angle.

  The invention described in claim 11 is characterized in that the predetermined angle of the video source unit (30, 50) described in claim 10 is 90 degrees.

  The invention described in claim 12 is an optical sheet (10b, 40b) used in the image source unit (10, 30, 35, 40, 50, 55) according to any one of claims 1-11. The prism portion (18, 26, 32, 37, 44, 52, 55) formed of an ultraviolet curable resin and arranged along the sheet surface so as to transmit light can be absorbed between the prism portions. An optical function sheet layer (17, 25, 31, 36, 43, 51, 56) having light absorbers (19, 33a, 33b, 38a, 38b, 45, 53a, 53b, 58a, 58b) arranged in parallel; The above problem is solved by providing an optical sheet that is provided on the opposite side of the optical function sheet layer from the image source side and includes layers (23, 47) containing an ultraviolet absorber.

  A thirteenth aspect of the present invention is a video display device comprising the video source unit according to any one of the first to eleventh aspects (10, 30, 35, 40, 50, 55). 1, 39) to solve the above problem.

  The invention according to claim 14 is an optical sheet (10b, 40b) comprising a plurality of layers, arranged in parallel along the sheet surface so as to be able to transmit light, and formed by an ultraviolet curable resin (18, 26, 32, 37, 44, 52, 55) and a light absorbing part (19, 33a, 33b, 38a, 38b, 45, 53a, 53b, 58a, 58b) arranged in parallel so as to be able to absorb light between the prism parts. The optical functional sheet layer (17, 25, 31, 36, 43, 51, 56) having the above, the anti-glare film layer (24, 49), the optical functional sheet layer, and the ultraviolet ray provided between the anti-glare film layer The said subject is solved by providing an optical sheet provided with the layer (23, 47) containing an absorber.

  The invention described in claim 15 is characterized in that the layer containing the ultraviolet absorber of the optical sheet (10b) described in claim 14 is a TAC film layer (23).

  The invention described in claim 16 is characterized in that the layer containing the ultraviolet absorber of the optical sheet (40b) described in claim 14 is a color tone correction layer (47).

  The invention according to claim 17 is the light absorbing portion (19, 33a, 33b, 38a, 38b, 45, 53a, 53b) of the optical sheet (10b, 40b) according to any one of claims 14-16. 58a and 58b) are filled with a binder (20) made of resin, and light-absorbing particles (21) having an average particle diameter of 1 μm or more are dispersed in the binder.

  According to an eighteenth aspect of the invention, the prism portion (18, 26) and the light absorbing portion of the optical function sheet layer (17, 25) of the optical sheet (10b ′) according to any one of the fourteenth to seventeenth aspects. (19) is formed extending in the longitudinal direction while maintaining a predetermined cross section, and two optical function sheet layers are laminated, and one of the two optical function sheet layers is an optical function sheet layer The light absorbing portion is laminated such that the longitudinal direction of the light absorbing portion and the longitudinal direction of the light absorbing portion of the other optical functional sheet layer of the two optical functional sheet layers have a predetermined angle.

  The invention according to claim 19 is characterized in that the predetermined angle of the optical sheet (10b ') according to claim 18 is 90 degrees.

  The invention according to claim 20 is the optical function sheet layer (31, 36, 51, 56) among the optical sheets (30, 35, 50, 55) according to any one of claims 14 to 17. The light absorbing portions (33a, 33b, 38a, 38b, 53a, 53b, 58a, 58b) are formed in a lattice shape that intersects at a predetermined angle.

  The invention according to claim 21 is characterized in that the predetermined angle of the optical sheet (30, 50) according to claim 20 is 90 degrees.

  The image source unit, the optical sheet, and the image display device of the present invention can efficiently suppress discoloration of members provided in the image source unit.

  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. However, the present invention is not limited to these embodiments.

  FIG. 1 is a diagram schematically showing a layer configuration of a cross section of a video source unit 10 according to the first embodiment. The video source unit 10 of the present embodiment is a so-called liquid crystal display panel unit. In the drawings shown below, some repetitive symbols may be omitted for easy viewing.

  The image source unit 10 includes a backlight 11, a polarizing plate 12, a liquid crystal panel 13, a polarizing plate 14, an adhesive layer 15, a PET film layer 16, an optical function sheet layer 17, an adhesive layer 22, a TAC film layer 23, and an antiglare. A film layer (AG layer) 24 is provided. Among these, the pressure-sensitive adhesive layer 15, the PET film layer 16, the optical function sheet layer 17, the pressure-sensitive adhesive layer 22, the TAC film layer 23, and the AG layer 24 are formed in advance as the optical sheet 10 b, and the backlight 11 and the polarizing plate 12. , 14 and a liquid crystal panel 13 are attached to a video source 10a. From the above-described configuration of the video source unit 10, it can be seen that when the video source unit 10 is provided in the video display device 1 (see FIG. 3), the right side of FIG. 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 backlight 11 is a light source of the liquid crystal panel 13. Here, a backlight used in a normal liquid crystal display panel unit can be used. This includes, for example, a form in which light emitting sources are arranged substantially uniformly in a plane to form a planar light source, or a light emitting source is arranged on an edge and a reflecting surface is used to finally form a planar shape. Examples include an edge input type that emits light.

  The polarizing plates 12 and 14 are a pair of optical elements arranged so as to sandwich the liquid crystal panel 13, and absorb polarized light having a vibration surface parallel to the absorption axis direction, while having a vibration surface orthogonal to the absorption axis direction. It has a function of transmitting the polarized light. The light of the backlight 11 that has passed through the polarizing plates 12 and 14 and the liquid crystal panel 13 becomes image light and is emitted to the viewer side.

  The liquid crystal panel 13 is one of the elements constituting the video source 10a in the video source unit 10, and video information to be emitted is shown here. The liquid crystal panel used for a normal liquid crystal display panel unit can be used here. Accordingly, in the video source unit 10, the video source 10 a is formed by the backlight 11, the polarizing plates 12 and 14, and the liquid crystal panel 13.

  The pressure-sensitive adhesive layers 15 and 22 are layers arranged so as to sandwich the PET film layer 16 and the optical function sheet layer 17, and are used to bond the PET film layer 16 and the optical function sheet layer 17 to other layers. Is a layer in which is arranged. The material of the pressure-sensitive adhesive used for the pressure-sensitive adhesive layers 15 and 22 is not particularly limited as long as it transmits light and can appropriately bond the PET film layer 16 and the optical function sheet layer 17 to each other. For example, PSA (pressure sensitive adhesive) can be used. The adhesive strength is, for example, about several N / 25 mm to 20 N / 25 mm.

  The PET film layer 16 is a film layer as a base material layer serving as a base for forming the optical functional sheet layer 17 on one surface of 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. Examples of general additives include phenol-based antioxidants, lactone-based stabilizers, and the like.

  Here, the PET film layer has been described as the base material layer, but the material is not necessarily made of PET, and other than the above, “polyester resin such as polybutylene terephthalate resin (PBT) or polytrimethylene terephthalate (PTT) resin. 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 functional sheet layer 17 includes prism portions 18, 18,... That are substantially trapezoidal in the cross section in the thickness direction of the sheet, and light absorbing portions 19, 19,... Disposed between the prism portions 18, 18,. It has. FIG. 2 shows an enlarged view focusing on the two light absorbing portions 19 and 19 and the prism portions 18, 18 and 18 adjacent thereto. The optical function sheet layer 17 will be described with reference to FIGS. 1 and 2.

  The prism portions 18, 18,... Are elements having a substantially trapezoidal cross section arranged such that the PET film layer 16 side is the lower base and the other side is the upper base. The prism portions 18, 18,... Are made of a light transmissive resin having a refractive index of Np. This is formed of, for example, epoxy acrylate, urethane acrylate or the like having a characteristic of being cured by ultraviolet rays. The size of Np is not particularly limited, but is preferably 1.49 to 1.56 from the viewpoint of availability of applicable materials. The image light is provided to the observer by transmitting the image light through the prism portions 18, 18,.

  The light absorbing portions 19, 19,... Are portions disposed between the prism portions 18, 18,. The light absorbing portions 19, 19,... Have a substantially triangular shape with the upper base side of the prism portions 18, 18,... As the base, and the apex opposite thereto is the lower base side of the prism portions 18, 18,. . The light absorbing parts 19, 19,... Are binder parts 20, 20,... Filled with a substance having a refractive index of Nb, and light absorbing particles 21, 21, mixed in the binder parts 20, 20,. … And. When external light is incident on and absorbed by the light absorbing portions 19, 19,..., The influence of the external light on the image light can be reduced, and the contrast can be improved.

  The binder material filled in the binder portions 20, 20,... Is made of a material having a refractive index Nb. Although the magnitude | size of Nb is not specifically limited, From a viewpoint of the availability of the material to apply, it is preferable that it is 1.49-1.56. 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.

  Here, the difference between the refractive index Np of the prism portions 18, 18,... And the refractive index Nb of the binder portions 20, 20,... Is preferably greater than 0 and not greater than 0.10. As a result, total reflection is appropriately performed at the interface between the prism portions 18, 18,... And the light absorbing portions 19, 19,..., And stray light or outside light is incident on the light absorbing portions 19, 19,. be able to.

  The light-absorbing particles 21, 21,... Are preferably particles having an average particle size of 1 μm or more from the viewpoint of availability and production. This is a particle such as carbon or a dye such as red, blue, yellow or black. It is colored in concentration. For this, for example, commercially available colored resin particles can be used. The refractive index Nr of the light absorbing particles 21, 21,... Is not particularly limited.

  Here, the light absorption performance of the light absorbing portions 19, 19,... 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 of 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 19, 19,... With respect to the sheet surface normal can be changed according to the purpose and is not particularly limited. However, in the case of a normal display device, it is preferably 6 to 15 degrees from the viewpoint of appropriately reflecting and absorbing external light and image light.

  As shown in FIGS. 1 and 2, the optical function sheet layer 17 has prism portions 18, 18,... Having a substantially trapezoidal cross section, and light absorbing portions 19, 19,. It 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. For example, the light absorbing portion may be a trapezoidal cross section instead of a triangular cross section. Further, the hypotenuse forming the interface between the prism portion and the light absorbing portion may be a polygonal line or a curved line.

  The TAC film layer 23 is a film formed of triacetyl cellulose and is used as a protective film. An ultraviolet absorber is added to the TAC film layer 23. As the ultraviolet absorber, known ones can be used, and examples thereof include benzophenone series, benzotriazole series, and acrylonitrile series. A thing excellent in heat resistance from viewpoints, such as manufacture and a weather resistance, is preferable.

  More specifically, as the ultraviolet absorber, 2,2′-methylenebis [4 (1,1,3,4-tetramethylbutyl 9-6- (2H-benzotriazol-2-yl) phenol)], 2 (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2,4-di-tert-butyl-6- (5-chlorobenzotriazol-2-yl) Phenol, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone and the like can be mentioned.

  Accordingly, the ultraviolet absorber is disposed at a position closest to the outside light incident side except for the AG layer 24. With this configuration, each layer provided on the video source side can be protected from the influence of ultraviolet rays contained in external light. In particular, the prism portions 18, 18,... Of the optical function sheet layer 17 are formed of an ultraviolet curable resin, and due to the property of being cured by irradiating with ultraviolet rays during production, it is possible to include an ultraviolet absorber here. Can not. In addition, many ultraviolet curable resins have the property of turning yellow when irradiated with a predetermined amount or more of ultraviolet light after curing. On the other hand, according to the image source unit 10, a layer containing an ultraviolet absorber is disposed on the viewer side (opposite the light source side) from the optical function sheet layer 17, so that the prism portions 18, 18,. Discoloration can be prevented.

  The AG layer 24 is a film that can prevent glare when an observer looks at the screen. As the antiglare film, a generally available AG film can be applied. In the present embodiment, this is the AG layer, but an AR layer may be arranged instead of the AG layer. The AR layer means an “anti-reflection layer” and is a layer that can prevent reflection.

  In the present embodiment, the AG layer 24 is laminated on the TAC film layer 23. However, as another aspect, the same effect can be obtained even if the surface of the TAC film layer 23 is subjected to anti-glare treatment (anti-glare treatment). Become.

  The video display device 1 including the video source unit 10 as described above operates as follows, for example. FIG. 3 is a diagram for explaining an optical path when the image source unit 10 is attached to the image display device 1 and the image display device 1 is operated to emit an image. In FIG. 3, the right side of the drawing is the observer side. The image display device 1 in the present embodiment can include a liquid crystal display device such as a liquid crystal display.

  When the image display device 1 is operated, the image light L1 is transmitted through each layer provided in the image source unit 10 and emitted to the observer as shown in FIG. Further, the image lights L2, L3 are totally reflected at the interface between the prism portions 18, 18,... And the light absorbing portions 19, 19,. At this time, since the hypotenuses of the light absorbing portions 19, 19,... Are inclined as described above, the angle of the light changes before and after reflection by the hypotenuse, and the image light can be emitted in a direction in which the viewing angle is widened. Become. Thereby, a wide viewing angle can be obtained.

  On the other hand, the external light L4 that has entered the video display device 1 as external light is already absorbed by the TAC film layer 23 before entering the light absorption unit 19 and is incident on the light absorption unit 19 here. Absorbed. In this way, a part of the external light is absorbed by the light absorbing portions 19, 19,... And the contrast can be improved. Further, the external light L5 incident on the prism portions 18, 18,... Has already been absorbed by the TAC film layer 23 before reaching the prism portions 18, 18,. Therefore, discoloration of the prism portions 18, 18,... By the external light L5 can be automatically suppressed.

  As described above, the image source unit 10 of the present invention can appropriately suppress discoloration of the constituent members.

  FIG. 4 is a cross-sectional view of a video source unit 10 ′ according to a first modification of the video source unit 10, and schematically shows the layer configuration. In the image source unit 10 ′, another optical function sheet layer 25 is laminated between the optical function sheet layer 17 and the adhesive layer 22 of the image source unit 10 described above. The optical function sheet layer 25 has the same configuration as that of the optical function sheet layer 17, but the light absorbing portion of the optical function sheet layer 25 (in FIG. 4, only the prism portion 26 appears, and the light absorbing portion is Is not shown)) is arranged so as to be orthogonal to the light absorbing portions 19, 19,... Of the optical function sheet layer 17. As a result, the direction in which the image light is diffused is expanded, and the light can be diffused in a wider range.

  Also in such a video source unit 10 ', discoloration of the constituent members of the video source unit 10' can be suppressed by the same effect as described above.

  FIG. 5 is a perspective view schematically showing the configuration of the optical function sheet layer 31 in the video source unit 30 according to the second modification. In FIG. 5, cross-sectional views are respectively shown on the upper and right sides of the perspective view for easy understanding. Since the configuration other than the optical function sheet layer 31 is the same as the configuration of the video source unit 10 described above, the description thereof is omitted here. In the perspective view of FIG. 5, the front side of the paper is the observer side, and the back of the paper is the light source side.

  In the optical functional sheet layer 31 shown in FIG. 5, light absorbing portions 33a, 33a,..., 33b, 33b,... Having a triangular cross section are formed in a lattice shape, and each region surrounded by the lattice is a prism portion 32. 32, and so on.

  Here, the light absorbing portions 33a, 33a,..., 33b, 33b,... Have a triangular cross section, but this may be a trapezoid. At this time, the trapezoidal short upper base is disposed on the light source side, and the trapezoidal long lower base is disposed on the observer side.

  In the second modified example, the light absorbing portions 33a, 33a,..., 33b, 33b,. The lattice shape intersects at a substantially right angle. By forming in this way, the viewing angle can be expanded in the horizontal and vertical directions by one optical function sheet layer 31. Accordingly, it is possible to widen the viewing angle in all directions while reducing the thickness of the optical sheet.

  FIG. 6 is a perspective view schematically showing the configuration of the optical function sheet layer 36 in the video source unit 35 according to the third modification. In FIG. 6, a cross-sectional view is shown on the right side of the perspective view for easy understanding. Since the configuration other than the optical function sheet layer 36 is the same as the configuration of the video source unit 10 described above, the description thereof is omitted here. In the perspective view of FIG. 6, the front side of the paper is the observer side, and the back side of the paper is the light source side.

  In the optical function sheet layer 36 shown in FIG. 6, light absorbing portions 38a, 38a,..., 38b, 38b,... Having a triangular cross section are formed in a lattice shape, and each region surrounded by the lattice is a prism portion 37, 37 ...

  Here, the light absorbing portions 38a, 38a,..., 38b, 38b,... Have a triangular cross section, but this may be a trapezoid. At this time, the trapezoidal short upper base is disposed on the light source side, and the trapezoidal long lower base is disposed on the observer side.

  Also in the third modified example, the light absorbing portion is formed in a lattice shape in one optical function sheet layer. The lattice shape intersects with a predetermined angle α. By forming in this way, the viewing angle characteristic to the predetermined angle corresponding to the α can be improved.

  FIG. 7 is a diagram schematically showing the layer structure of the video source unit 40 according to the second embodiment. The video source unit 40 of this embodiment is a plasma display unit.

  The image source unit 40 includes a plasma display panel 41, an adhesive layer 42, an optical function sheet layer 43, a PET film layer 46, a color tone correction layer 47, an antistatic film (AS) layer 48, and an antiglare film (AG) layer 49. I have. Among these, the pressure-sensitive adhesive layer 42, the optical function sheet layer 43, the PET film layer 46, the color tone correction layer 47, the AS layer 48, and the AG layer 49 are formed in advance as the optical sheet 40 b and are an image source that is the plasma display panel 41. It is affixed to 40a. Each of the above 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 plasma display panel 41 is a video source in the video source unit 40, and video information to be emitted is displayed here. The plasma display panel 41 can self-emit. The image source unit 40 can be a panel used in a normal plasma display panel unit.

  The adhesive layer 42 is a layer in which an adhesive for adhering the optical function sheet layer 43 to the plasma display panel 41 is disposed as will be described later. The material of the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer 42 is not particularly limited as long as it transmits light and can be appropriately bonded. Examples thereof include an acrylic copolymer, and the adhesive strength thereof is, for example, about several N / 25 mm to 20 N / 25 mm.

  As can be seen from FIG. 7, the optical functional sheet layer 43 has the same basic structure as the optical functional sheet layer 17 except that the orientation is different from that of the optical functional sheet layer 17 described above. However, in the image source unit 41 of the present embodiment, as shown in FIG. 8 in which a part of the optical function sheet layer 43 is enlarged, the interface between the light absorbing portions 45, 45,... And the prism portions 44, 44,. The angle φ of the hypotenuse (two sides extending in the sheet thickness direction) formed by the sheet surface with respect to the normal to the sheet surface can be changed according to the purpose and is not particularly limited. From the viewpoint of reflecting and absorbing light, it is preferably greater than 0 degree and 6 degrees or less.

  Since the PET film layer 46 and the AG layer 49 are the same as those of the PET film layer 16 and the AG layer 24, the description thereof is omitted. Also in this case, an AR layer may be arranged instead of the AG layer.

  The color tone correction layer 47 is sometimes referred to as a Tint layer, and is a layer in which a film that corrects the color of the image light from the plasma display panel 41 and provides an image with an appropriate hue for the observer is disposed. 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.

  In the present embodiment, an ultraviolet absorber is added to the color tone correction layer. As the ultraviolet absorber, known ones can be used, and examples thereof include benzophenone series, benzotriazole series, and acrylonitrile series. A thing excellent in heat resistance from viewpoints, such as manufacture and a weather resistance, is preferable.

  More specifically, as the ultraviolet absorber, 2,2′-methylenebis [4 (1,1,3,4-tetramethylbutyl 9-6- (2H-benzotriazol-2-yl) phenol)], 2 (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2,4-di-tert-butyl-6- (5-chlorobenzotriazol-2-yl) Phenol, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone and the like can be mentioned.

  Accordingly, the ultraviolet absorber is disposed at a position closest to the outside light incident side except for the AS layer 48 and the AG layer 49. With this configuration, each layer provided on the video source side can be protected from the influence of ultraviolet rays contained in external light. In particular, the prism portions 44, 44,... Of the optical function sheet layer 43 are formed of an ultraviolet curable resin, and due to the property of being cured by irradiating with ultraviolet rays during production, it is possible to include an ultraviolet absorber here. Can not. In addition, many ultraviolet curable resins have the property of turning yellow when irradiated with a predetermined amount or more of ultraviolet light after curing. On the other hand, according to the image source unit 40, a layer containing an ultraviolet absorber is arranged on the observer side (opposite the light source side) from the optical function sheet layer 43, so that the prism portions 44, 44,. Discoloration can be prevented.

  The AS layer 48 is a film that can prevent charging, that is, static electricity. A commonly available AS film can be applied to this.

  Furthermore, the image source unit may be provided with functional film layers such as a layer that blocks electromagnetic waves, a layer that blocks infrared rays, and a layer that blocks neon lines.

  The video display device 39 including the video source unit 40 as described above operates, for example, as follows. FIG. 9 is a diagram for explaining an optical path when the image source unit 40 is attached to the image display device 39 and the image display device 39 is operated to emit an image. In FIG. 9, the right side of the drawing is the observer side. Examples of the video display device 39 in the present embodiment include a plasma display.

  When the image display device 39 is operated, the image light L11 passes through each layer provided in the image source unit 40 and is emitted to the observer as shown in FIG. The image lights L12 and L13 are totally reflected at the interface between the prism portions 44, 44,... And the light absorbing portions 45, 45,. At this time, the oblique sides of the light absorbing portions 45, 45,... Have an angle different from that of the light absorbing portions 19, 19,... The image light can be emitted. Thereby, the brightness and contrast of the image light can be improved.

  On the other hand, the external light L14 incident on the video display device 39 as external light is already absorbed by the color tone correction layer 47 before entering the light absorption unit 45, and is incident on the light absorption unit 45 here. Absorbed. In this way, a part of the external light is absorbed by the light absorbing portions 45, 45,... And the contrast can be improved. Further, the external light L15 incident on the prism portions 44, 44,... Has already been absorbed by the color tone correction layer 47 before reaching the prism portions 44, 44,. Therefore, the discoloration of the prism portions 44, 44,... By the external light L15 is automatically suppressed.

  FIG. 10 is a perspective view schematically showing the configuration of the optical function sheet layers 51 and 51 ′ in the image source units 50 and 50 ′ according to the fourth modification. In FIG. 10, cross-sectional views are respectively shown above and to the right of the perspective view for easy understanding. Since the configuration other than the optical function sheet layers 51 and 51 'is the same as the configuration of the video source unit 39 described above, the description thereof is omitted here. In the perspective view of FIG. 10, the front side of the paper is the observer side, and the back of the paper is the light source side.

  In the optical function sheet layer 51 shown in FIG. 10A, light absorbing portions 53a, 53a,..., 53b, 53b,... Having a triangular cross section are formed in a lattice shape, and each region surrounded by the lattice is a prism. The parts are 52, 52,. On the other hand, in the optical function sheet layer 51 ′ shown in FIG. 10B, the light absorbing portions 53a ′, 53a ′,..., 53b ′, 53b ′,. Each region formed and surrounded by a lattice is a prism portion 52 ′, 52 ′,.

  In the fourth modification example, the light absorbing portions are formed in a lattice shape in one optical function sheet layer 51, 51 'as described above. The lattice shape intersects at a substantially right angle. By forming in this way, the optical path can be controlled in the horizontal and vertical directions by one optical function sheet layer 51, 51 ', and the contrast and brightness can be further improved.

  Here, the light absorbing portions 53a, 53a,..., 53b, 53b,... Have a triangular cross section, but this may be a trapezoid. At this time, the trapezoidal short upper base is arranged on the viewer side and the trapezoidal long lower base is arranged on the light source side.

  FIG. 11 is a perspective view schematically showing the configuration of the optical function sheet layers 56 and 56 ′ in the optical sheets 55 and 55 ′ according to the fifth modification. In FIG. 11, a cross-sectional view is shown on the right side of the perspective view for easy understanding. Since the configuration other than the optical function sheet layers 56 and 56 'is the same as the configuration of the video source unit 39 described above, the description thereof is omitted here. In the perspective view of FIG. 11, the front side of the paper is the observer side, and the back of the paper is the light source side.

  In the optical function sheet layer 56 shown in FIG. 11A, light absorbing portions 58a, 58a,..., 58b, 58b,... Having a triangular cross section are formed in a lattice shape, and each region surrounded by the lattice is a prism. It becomes part 57,57, .... On the other hand, in the optical function sheet layer 56 ′ shown in FIG. 11B, the light absorbing portions 58a ′, 58a ′,..., 58b ′, 58b ′,. Each region formed and surrounded by a lattice is a prism portion 57 ′, 57 ′,.

  Also in the fifth modified example, the light absorbing portions are formed in a lattice shape in one optical function sheet layer 55, 55 '. The lattice shape intersects with predetermined angles γ and δ. By forming in this way, desired optical characteristics can be obtained for a predetermined angle corresponding to γ and δ, and external light can be absorbed.

  Here, the light absorbing portions 58a, 58a,..., 58b, 58b,... Have a triangular cross section, but may be trapezoidal. At this time, the trapezoidal short upper base is arranged on the viewer side and the trapezoidal long lower base is arranged on the light source side.

  Next, examples will be shown and described in more detail. However, the present invention is not limited to the scope of the examples.

In the examples, an optical sheet (Example 1) in which an adhesive layer, a PET film layer, an optical functional sheet layer, an adhesive layer, a TAC film layer, and an AG layer are laminated in this order is prepared, and light containing ultraviolet rays is irradiated. Then, the optical characteristics at that time were examined. The optical sheet of Example 1 contains an ultraviolet absorber in the TAC film layer. Irradiation of light including ultraviolet rays was performed by turning on a 1500 W xenon lamp and irradiating it for 1000 hours. The xenon lamp was disposed on the AG side so that the intensity was 500 W / m ² at the position of the optical sheet.
Moreover, the optical sheet which laminated | stacked the adhesive layer, PET film layer, and the optical function sheet layer in this order was prepared as the comparative example 1, and the same evaluation was performed. In this case, the optical function sheet layer is irradiated with almost no ultraviolet light of the xenon lamp. Table 1 shows the results.

  As optical characteristics, total light transmittance τt, haze value H, x, y, and YI value (yellowness) were obtained. Here, x and y represent chromaticity, and x and y were calculated from the tristimulus values X, Y, and Z by a known conversion formula. X, Y, Z, and YI were obtained by measuring the spectral transmittance with a spectrophotometer (UV-2400PC, Shimadzu Corporation). The total light transmittance τt and the haze value H were measured with a haze meter (HR-100, Murakami Color Research Laboratory). As a result, as can be seen from Table 1, the change in the optical characteristics before and after the irradiation in Example 1 was less than that in Comparative Example 1 in all the optical characteristics.

  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 image source unit, an optical sheet, and an image display device that involve such a change are also included in the technical scope of the present invention. Must be understood as being.

It is the figure which showed the cross section of the video source unit which concerns on 1st embodiment, and represented the layer structure typically. It is the figure which expanded and showed a part of video source unit shown in FIG. It is a figure for demonstrating the optical path of a video display apparatus. It is the figure which showed the cross section of the image source unit which concerns on a 1st modification, and represented the layer structure typically. It is a figure for demonstrating the optical function sheet | seat layer among the image source units which concern on a 2nd modification. It is a figure for demonstrating the optical function sheet | seat layer among the image source units which concern on a 3rd modification. It is the figure which showed the cross section of the video source unit which concerns on 2nd embodiment, and represented the layer structure typically. It is the figure which expanded and showed a part of video source unit shown in FIG. It is a figure for demonstrating the optical path of a video display apparatus. It is a figure for demonstrating the optical function sheet | seat layer among the image source units which concern on a 4th modification. It is a figure for demonstrating the optical function sheet | seat layer among the image source units which concern on a 5th modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image display apparatus 10 Image source unit 10a Image source 10b Optical sheet 11 Backlight 12 Polarizing plate 13 Liquid crystal panel 14 Polarizing plate 15 Adhesive layer 16 PET film layer 17 Optical functional sheet layer 18 Prism unit 19 Light absorption unit 20 Binder unit 21 Light Absorbing Particles 22 Adhesive Layer 23 TAC Film Layer 24 AG Layer 25 Optical Function Sheet Layer 39 Image Display Device 40 Image Source Unit 40a Image Source 40b Optical Sheet 41 Plasma Display Panel 42 Adhesive Layer 43 Optical Function Sheet Layer 44 Prism Unit 45 Light absorption part 46 PET film layer 47 Color tone correction layer 48 AS layer 49 AG layer

Claims (21)

An image source that emits an image by self-light emission or combined with another light source, and is arranged on the viewer side from the image source, and can control the light from the image source to be emitted to the viewer side An image source unit comprising an optical sheet having a plurality of layers,
The optical sheet is
An optical functional sheet layer having a prism portion that is arranged in parallel along the sheet surface so as to transmit light and is formed of an ultraviolet curable resin, and a light absorbing portion that is arranged in parallel so as to be able to absorb light between the prism portions,
An image source unit comprising: an optical function sheet layer disposed on a side opposite to the image source side, and a layer containing an ultraviolet absorber.   The video source unit according to claim 1, wherein the optical sheet has a TAC film layer, and the layer containing the ultraviolet absorber is the TAC film layer.   The image source unit according to claim 2, wherein an anti-glare process is performed on a side surface of the TAC film layer opposite to the image source side.   The image source unit according to claim 2, wherein the optical sheet includes an anti-glare film layer, the TAC film layer, and an adhesive layer in this order from the observer side.   The image source unit according to claim 1, wherein the optical sheet has a color tone correction layer, and the layer containing the ultraviolet absorber is the color tone correction layer.   The image source unit according to claim 5, wherein the optical sheet includes an anti-glare film layer and the color tone correction layer from the viewer side.   The light absorption part is filled with a binder made of a resin, and light absorption particles having an average particle diameter of 1 μm or more are dispersed in the binder. The video source unit described in 1.   The prism portion and the light absorbing portion of the optical function sheet layer are formed to extend in the longitudinal direction while maintaining a predetermined cross section, and the two optical function sheet layers are laminated, and the two layers of optical The longitudinal direction of the light absorbing portion of one of the optical functional sheet layers of the functional sheet layer, and the longitudinal direction of the light absorbing portion of the other optical functional sheet layer of the two optical functional sheet layers The video source unit according to claim 1, wherein the video source units are stacked so as to have a predetermined angle.   9. The video source unit according to claim 8, wherein the predetermined angle is 90 degrees.   The image source unit according to claim 1, wherein the light absorbing portions of the optical function sheet layer are formed in a lattice shape that intersects at a predetermined angle.   The video source unit according to claim 10, wherein the predetermined angle is 90 degrees. An optical sheet used in the image source unit according to any one of claims 1 to 11,
An optical functional sheet layer having a prism portion that is arranged in parallel along the sheet surface so as to transmit light and is formed of an ultraviolet curable resin, and a light absorbing portion that is arranged in parallel so as to be able to absorb light between the prism portions,
An optical sheet comprising: an optical function sheet layer disposed on a side opposite to the image source side, and a layer containing an ultraviolet absorber.   A video display device comprising the video source unit according to claim 1. An optical sheet comprising a plurality of layers,
An optical functional sheet layer having a prism portion that is arranged in parallel along the sheet surface so as to transmit light and is formed of an ultraviolet curable resin, and a light absorbing portion that is arranged in parallel so as to be able to absorb light between the prism portions,
An anti-glare film layer;
An optical sheet comprising: an optical function sheet layer; and a layer containing an ultraviolet absorber provided between the antiglare film layer.   The optical sheet according to claim 14, wherein the layer containing the ultraviolet absorber is a TAC film layer.   The optical sheet according to claim 14, wherein the layer containing the ultraviolet absorber is a color tone correction layer.   The light absorbing portion is filled with a binder made of resin, and light absorbing particles having an average particle diameter of 1 μm or more are dispersed in the binder. The optical sheet according to 1.   The prism portion and the light absorbing portion of the optical function sheet layer are formed to extend in the longitudinal direction while maintaining a predetermined cross section, and the two optical function sheet layers are laminated, and the two layers of optical The longitudinal direction of the light absorbing portion of one of the optical functional sheet layers of the functional sheet layer, and the longitudinal direction of the light absorbing portion of the other optical functional sheet layer of the two optical functional sheet layers The optical sheet according to any one of claims 14 to 17, wherein the optical sheets are laminated so as to have a predetermined angle.   The optical sheet according to claim 18, wherein the predetermined angle is 90 degrees.   The optical sheet according to any one of claims 14 to 17, wherein the light absorbing portions of the optical function sheet layer are formed in a lattice shape that intersects at a predetermined angle.   21. The optical sheet according to claim 20, wherein the predetermined angle is 90 degrees.

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