JP2011075947A - Optical member and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical member and a method of improving the manufacturing yield of the optical member. <P>SOLUTION: The optical member includes: a plurality of belt-like flat surfaces which are extended in one direction, are arrayed in the other direction intersecting the one direction and absorb light; a light absorption surface which is erected from one side edge facing an adjacent other belt-like flat surface and absorbs light, on each of the plurality of belt-like flat surfaces; a narrow erection surface which erects from the other side edge facing the adjacent other flat surface and is narrower than the light absorption surface, on each of the plurality of belt-like flat surfaces; and a light control surface which controls the propagation direction of incident light while connecting the top end of the light absorption surface with the top end of the narrow erection surface between respective ones of the plurality of belt-like flat surfaces, wherein the width relating to the other direction of the respective ones of the plurality of belt-like flat surfaces is narrower than an interval between the light absorption surface and the light control surface which are connected to one light control surface. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical member and a manufacturing method thereof.

  There is an optical member that improves the contrast of an observation image by disposing the observer in front of the display image and observing the display image through the optical member. Patent Document 1 below describes the structure of an optical member having a prism lens on the display image side surface. Patent Document 2 below describes the structure of an optical member including a region to which light absorbing particles are added.

  Patent Document 3 below describes an optical member having a slope that changes the optical path of incident light. Patent Document 4 below describes the structure of an optical member having a sawtooth portion in which slopes that transmit light and slopes having a light shielding film are alternately arranged. Patent Document 5 below describes the structure of a display device including an optical member.

JP 2006-085050 A JP 2006-145611 A JP 2006-079998 A JP 2006-186385 A JP 2000-321993 A

  The above optical component has a light absorption layer that absorbs external incident light. The light absorption layer is selectively applied to a specific region arranged so as not to affect the outgoing light emitted from the image side. However, the production yield of the optical component may decrease due to uneven application of the light absorbing layer.

  Therefore, in order to solve the above problem, as a first aspect of the present invention, a plurality of flat strip surfaces that absorb light by being arranged in another direction extending in one direction and intersecting one direction, In each of the belt-like flat surfaces, a light-absorbing surface that absorbs light rising from one edge facing the other belt-like flat surface adjacent to each other, and another belt-like flat surface that is adjacent in each of the plurality of belt-like flat surfaces Propagation of incident light while connecting the front end of the light-absorbing surface and the front end of the narrow-upright surface between the narrow upright surface that is narrower than the light-absorbing surface and each of the plurality of flat belt-like surfaces. And a light control surface that controls the direction, and the width of each of the plurality of strip-shaped flat surfaces in the other direction is narrower than the distance between the light absorption surface and the light control surface connected to one light control surface Is provided.

  Moreover, as a second aspect of the present invention, there is provided an image display device comprising the optical member and an image display unit affixed on the side where the light absorption surface stands with respect to the belt-like flat surface.

  Furthermore, as a third aspect of the present invention, in each of the plurality of strip-shaped flat surfaces that absorb light by being arranged in another direction that extends in one direction and intersects the one direction, Light absorption surface that stands up from one edge facing another adjacent flat band surface, absorbs light, is narrower than the light absorption surface, and faces another adjacent flat band surface in each of the multiple flat band surfaces There is a narrow rising surface that rises from the other edge, and a light control surface that controls the propagation direction of incident light while connecting the tip of the light absorbing surface and the tip of the narrow rising surface between each of the plurality of flat strip surfaces. A width of each of the plurality of belt-like flat surfaces in the other direction is a base that is narrower than a distance between the light absorption surface connected to one light control surface and the light control surface; Applying a light absorbing layer to a plurality of belt-like flat surfaces and a light absorbing surface Method for producing wood is provided.

  The above summary of the present invention does not enumerate all necessary features of the present invention. Sub-combinations of these feature groups can also be an invention.

1 is a diagram schematically showing the structure of an image display device 100. FIG. 2 is a partially enlarged sectional view of the image display device 100. FIG. It is a figure explaining the change of the characteristic of the optical member 200 by a refractive index difference. It is a figure which shows the light control layer forming apparatus 300 typically. It is a figure which shows the light absorption layer forming apparatus 400 typically. It is a figure which shows the planarization layer forming apparatus 500 typically. 3 is a partial cross-sectional view showing specifications of a light control layer 210. FIG. It is a figure which expands and shows the section of optical member 200 partially. 6 is a graph showing the influence of the difference in refractive index of members on the characteristics of the optical member 200.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solution of the invention.

  FIG. 1 is a diagram schematically showing the structure of the image display device 100. The image display device 100 includes an image display unit 101 and an optical member 200. The optical member 200 is disposed on the observer 99 side who observes the image displayed by the image display unit 101. Accordingly, the observer 99 observes the image display unit 101 through the optical member 200.

  The image display unit 101 is, for example, a liquid crystal display panel. The image display unit 130 is disposed between the pair of transparent substrates 120 and 140 and is closer to the viewer 99, and the image generator 130 is connected to the viewer 99. And a surface light source 110 disposed on the back side of the.

  The surface light source 110 illuminates the transmission image generated by the image generation unit 130 from the back, and projects it toward the observer 99. As the surface light source, any light source having uniform luminance can be freely selected. In addition to a surface light emitter such as an EL sheet, a lighting device in which a point light source array such as a plurality of light emitting diodes and a condensing lens are used is used. Can do.

  The structure of the image display unit 101 is not limited to the liquid crystal display panel. For example, the effect of the optical member 200 is also effective in a plasma display (PDP), an organic EL display, a surface conduction electron-emitting device display, and the like. It can also be used for operation panels of vehicles, protective glass for instruments, window glass, and the like.

  The optical member 200 includes a surface protective layer 240, a base material 211, a light control layer 210, a light absorption layer 220, and a planarization layer 230 that are sequentially stacked from the side closer to the observer 99. The surface protective layer 240 has a hard material coating or the like, and protects the surface of the image display device 100 from scratches or the like. The base material 211 supports the light control layer 210 described below.

  The light control layer 210 is formed of a transparent material such as resin. The light control layer 210 has a flat surface facing the observer 99, whereas the surface facing the image display unit 101 has undulations. The light absorption layer 220 is disposed on a part of the surface having the undulations in the surface of the light control layer 210.

  The planarization layer 230 planarizes the surface of the light control layer 210 and improves the adhesion to the image display unit 101. Furthermore, the planarization layer 230 may be formed of an adhesive material. Thereby, the optical member 200 can be directly attached to the image display unit 101. Therefore, the manufacturing of the image display device 100 can be facilitated, and the layer configuration of the image display device 100 can be simplified to reduce the thickness.

  From the viewpoint of using the flattening layer 230 as an adhesive when the optical member 200 is bonded to the image display unit 101, the flattening layer 230 has a certain thickness or more in each part of the light control layer 210. Specifically, it is preferable to have a thickness of 5 μm or more. In other words, it is preferable that the thickness from the apex of the wedge-shaped structure of the light control layer 210 to the surface of the planarization layer 230 is 5 μm or more, as indicated by the symbol T in the drawing.

  As a result, when the flattening layer 230 is pressed against the image display unit 101, the flattening layer 230 deforms following the surface shape of the image display unit 101 and adheres well to the image display unit 101. Further, bubbles and wrinkles are not generated between the optical member 200 and the image display unit 101, and the optical member 200 and the image display unit 101 can be attached smoothly. Furthermore, the planarization layer 230 becomes a buffer layer, and the sharp tip of the light control layer 210 can be protected.

  Further, the planarization layer 230 may be formed of a non-ultraviolet curable resin. Thereby, high functional additives such as an ultraviolet absorber, an infrared absorber, a metal catalyst deactivator, and an antistatic agent can be added to the planarizing layer 230. These additives may cause curing inhibition when used in an ultraviolet curable resin.

  The optical member 200 is disposed for the purpose of improving the contrast of the image when the observer 99 observes the image displayed by the image display unit 101. That is, when incident light incident from the lighting fixture 98 or the like is reflected toward the viewer 99 on the surface of the image display unit 101, the contrast of the display image viewed from the viewer 99 is lowered. Therefore, the optical member 200 gives directivity to the reflection characteristics on the surface of the image display unit 101 and selectively suppresses reflection of incident light.

  FIG. 2 is a partially enlarged cross-sectional view of the image display device 100. Elements common to those in FIG. 1 are denoted by the same reference numerals and redundant description is omitted.

  Of the surfaces of the light control layer 210, the surface facing the image display unit 101 has a flat surface 212, a light absorption surface 214, a light control surface 216, and a narrow standing surface 218. Each of the flat surface 212, the light absorption surface 214, the light control surface 216, and the narrow upright surface 218 forms a belt-like surface that is continuous perpendicular to the paper surface. Further, the same shape is repeatedly arranged in the vertical direction on the paper. Therefore, the vertical cross-sectional shape of the light control layer 210 will be described below.

  The flat surface 212 is formed substantially parallel to the surface of the image display device 100 on the viewer 99 side. Note that the surface of the flat surface 212 is preferably roughened. That is, as will be described later, since the light absorbing layer 220 is applied to the flat surface 212, the image light of the display image is not transmitted. However, when the flat surface 212 is roughened and the reflected light is scattered, the reflected light on the flat surface 212 is difficult to be visually recognized by the observer 99. Thereby, the contrast fall can be suppressed further.

  The light absorbing surface 214 rises toward the image display unit 101 at a substantially right angle from one end of the flat surface 212. In addition, the light absorption surface 214 in the figure is not upright with respect to the flat surface 212 but is inclined. Thereby, when shape | molding the light-control layer 210, it can make it easy to extract a type | mold.

  The narrow upright surface 218 stands up toward the image display unit 101 at a substantially right angle from the other end of the flat surface 212. Similar to the angle formed by the light absorbing surface 214 with respect to the flat surface, the angle formed by the narrow upright surface 218 with respect to the flat surface is selected for the purpose of facilitating removal of the mold when forming. Therefore, the narrow upright surface 218 may form substantially the same angle as the light absorbing surface 214 with respect to the flat surface 212 or an angle closer to a right angle. However, the narrow rising surface 218 has a narrow rising width from the flat surface 212 and ends at a position far away from the image display unit 101.

  The light control surface 216 is disposed at a position where the tip of the light absorption surface 214 and the tip of the narrow upright surface 218 are coupled. For this reason, the inclination with respect to the horizontal surface of the light control surface 216 is larger than the inclination with respect to the horizontal surface of the light absorption surface 214 and the narrow standing surface 218.

  The light absorption layer 220 is disposed on the surfaces of the flat surface 212, the light absorption surface 214, and the narrow raised surface 218. The light control layer 210 is formed of a material such as a transparent resin, whereas the light absorption layer 220 is formed of an opaque material that does not absorb and transmit light, for example, a black resin.

  A part of the incident light L1 incident on the optical member 200 from the observer 99 side is blocked by the light absorption layer 220 and absorbed. Thereby, a part of the incident light L1 does not reach the image display unit 101, and the influence of the incident light on the display image is reduced.

  Further, part of the incident light L <b> 2 passes through the light control surface 216 and reaches the surface of the image display unit 101. However, the reflected light reflected by the surface of the image display unit 101 is absorbed by the light absorption layer 220 in the process of passing through the light control layer 210 again. This further suppresses a decrease in contrast of the display image due to the incident light.

  Thus, the optical member 200 has a structure in which part of the incident light L1 and L2 incident from the observer 99 side does not return to the observer 99 side. The image lights I1 and I2 emitted from the image display unit 101 directly reach an external observer except for a small area directly blocked by the light absorption layer 220.

  Further, since part of the incident light L2 is incident on the light control surface 216 obliquely, the incident light L2 is incident on the flattening layer 230 from the light control layer 210, and the reflected light of the incident light L2 is flattened. The optical path of the incident light L2 is refracted in two stages, that is, from the layer 230 to the light control layer 210. Thereby, a part L2 of incident light is easily absorbed by the light absorption layer 220.

  Note that most of the incident light that lowers the contrast of the display image is emitted from a light source positioned above the image display device 100, such as a lighting fixture 98 or the sun arranged on the ceiling. For this reason, the optical member 200 is required to efficiently absorb incident light incident on the optical member 200 obliquely from above with respect to the image display unit 101.

  From such a viewpoint, it is preferable to increase the incident light blocked by the light absorption layer 220 by narrowing the interval (upper and lower intervals in the illustrated example) of the light absorption layer 220. In addition, it is also preferable that the inclination of the light control surface 216 is made closer to the inclination of the light absorption surface 214 to increase the range in which the total reflection of incident light on the light control surface 216 occurs.

  Furthermore, when the refractive index of the planarization layer 230 is lower than the refractive index of the light control layer 210, a part of the incident light L3 incident from the observer 99 side is totally at the interface between the light control surface 216 and the planarization layer 230. Reflected. The reflected light reflected at the interface propagates in the light control layer 210 toward the light absorption surface 214 and is eventually absorbed by the light absorption layer 220 at the light absorption surface 214. As a result, the contrast reduction of the display image due to the part L3 of the incident light is further suppressed. This point will be described in more detail with reference to FIG.

  FIG. 3 is a diagram illustrating the relationship between the refractive index difference between the light control layer 210 and the planarization layer 230 and the external light absorption angle θ. As shown in the figure, the external light absorption angle θ is an angle narrower than the right angle between the incident light L incident from the observer 99 side and the incident surface of the optical member 200, and the light absorption layer 220 is blocked. It means the largest incident angle of incident light L.

The optical member 200 has an external light absorption angle θ ₁ that is determined by the light absorption layer 220 directly blocking the incident light L ₁₀ regardless of the refractive index n ₂ of the light control layer 210. Here, when the refractive index n ₂ of the light control layer 210 is larger than the refractive index n _{1 of the} planarization layer 230, total reflection occurs at the interface between the light control layer 210 and the planarization layer 230. Therefore, the incident angle of the incident light L ₂₀ that is incident on the light absorbing layer 220 after being totally reflected at the interface is a major external light absorbing angle theta ₂ than the external light absorption angle theta _1.

Further, if the difference between the refractive index n ₁ of the refractive index n ₂ and the planarization layer 230 of the light control layer 210 becomes larger, the critical angle of total reflection occurring at the interface between the light control layer 210 and the planarization layer 230 ( (Indicated by θ _c1 and θ _c1 in the figure) becomes smaller. Accordingly, the incident angle of the incident light L ₃₀ that is incident on the light absorbing layer 220 after being totally reflected at the interface is a major external light absorbing angle theta ₃ than the external light absorption angle theta _2.

In this way, by making the refractive index n ₂ of the light control layer 210 larger than the refractive index n ₁ of the planarization layer 230, the light control surface 216 causes total reflection on the incident light L ₂₀ and L _30. Large external light absorption angles θ ₂ and θ ₃ are obtained. Thereby, the contrast improvement effect of the image by the optical member 200 can be obtained in a wider visual field range.

  Moreover, when producing the optical member 200 that can obtain a constant external light absorption angle θ, the thickness of the optical member 200 can be reduced by the above structure. Thereby, it contributes also to thickness reduction of the image display apparatus 100 whole.

  FIG. 4 is a diagram schematically showing the structure of the light control layer forming apparatus 300 used in a part of the manufacturing process of the optical member 200. The elements of the optical member 200 that have already been described are assigned the same reference numerals as those in FIGS. 1 and 2, and redundant description is omitted.

  The light control layer forming apparatus 300 includes a delivery roll 310, a guide roll 330, a coater 340, an ultraviolet lamp 350, a rotating mold 360, and a take-up roll 370. The light control layer forming apparatus 300 is disposed between a feed roll 310 that feeds the base material 211 and a take-up roll 370 that winds up the manufactured light control layer 210.

  A path of the base material 211 between the feed roll 310 and the take-up roll 370 is defined by a plurality of guide rolls 330. The base material 211 is coated with a transparent resin to be the light control layer 210 and transported, and finally becomes a part of the light control layer 210.

  The coater 340 applies an ultraviolet curable resin to one side of the substrate 211. As the coater 340, a die coater or a roll coater can be arbitrarily selected and used.

  The ultraviolet curable resin applied to the substrate 211 is pressed against the rotating mold 360. As a result, the shape formed on the surface of the rotating mold 360 is transferred to the ultraviolet curable resin. On the surface of the rotating mold 360, a shape complementary to the cross-sectional shape of the light control layer 210 is engraved so as to show an enlarged view of the cross-section indicated by the dotted line A as viewed from the line of sight a. The rotary mold 360 can be produced by, for example, direct cutting using a diamond cutting blade and a roll lathe.

  The substrate 211 in a state of being wound around the rotary mold 360 is irradiated with ultraviolet rays from the back surface by the ultraviolet lamp 350. As a result, the UV curable resin is cured in a shape complementary to that of the rotating mold 360, and the light control layer 210 is shown in an enlarged manner in FIG. It is formed continuously. The base material 211 having the unique cross-sectional shape of the light control layer 210 is taken up by the take-up roll 370.

  In FIG. 4, the shape of the light control layer 210 is repeated in the same direction as the feeding direction of the base material 211 so that the shape appears in the figure. However, in consideration of the repetition of the shape of the narrow rod shape, the longitudinal directions of the respective band-shaped surfaces forming the flat surface 212, the light absorption surface 214, the light control surface 216, and the narrow upright surface 218 are It is desirable to match the feed direction. Thereby, the light control layer 210 can be easily detached from the rotary mold 360. Further, as will be described with reference to FIGS. 4 and 5, bubbles or the like are less likely to occur when a resin or the like is applied to the surface of the light control layer 210. Therefore, the productivity of the optical member 200 can be improved.

  The light control layer 210 has a cross-sectional shape with a high aspect ratio in which the ratio between the arrangement pitch and the height is large. For this reason, curing shrinkage occurs in the process of transferring the shape from the rotating mold 360 and curing with ultraviolet rays. At this time, since uneven curing may occur due to a difference in shrinkage rate between the base material 211 and the light control layer 210, the base material 211 and the light control layer 210 are formed of the same material as the light control layer 210. It is preferable to provide a blank layer having a thickness of about 5 μm to about 40 μm. As a result, the internal stress caused by the difference in shrinkage rate is relaxed and the unevenness of curing is reduced.

  FIG. 5 is a view schematically showing the structure of the light absorption layer forming apparatus 400 used in a part of the manufacturing process of the optical member 200. The elements of the optical member 200 that have already been described are assigned the same reference numerals as those in FIGS. 1 and 2, and redundant description is omitted. The light absorption layer forming apparatus 400 includes a delivery roll 410, a guide roll 430, a coating apparatus 420, a heater 440, a buff 460, and a take-up roll 470.

  The light absorbing layer forming apparatus 400 is a winding roll 410 that sends out the light control layer 210 manufactured by the light control layer forming apparatus 300 shown in FIG. 4 and a winding that winds the light control layer 210 coated with the light absorbing layer 220. It is arranged between the take-up roll 470. The path of the light control layer 210 between the delivery roll 410 and the take-up roll 470 is defined by a plurality of guide rolls 430.

  In the light absorbing layer forming apparatus 400, a coating apparatus 420 is disposed immediately after the delivery roll 410. The coating device 420 discharges a solvent-drying resin that is a material of the light absorption layer 220 toward the light control layer 210. Since the discharged resin particles fly in a certain direction, the surface of the light control layer 210 mainly absorbs light, as shown in the enlarged view of the cross section indicated by the dotted line C as viewed from the line of sight c. It adheres to the surface 214. However, the resin that becomes the light absorption layer 220 may also adhere to the light control surface 216.

  A heater 440 is disposed after the coating device 420. Thereby, the solvent dry resin applied to the light absorption surface 214 is heated, and the solvent is removed. As the resin for forming the light absorption layer 220, a thermosetting resin may be used. However, it is preferable to use a solvent drying type resin because of leveling properties and ease of control of the drying time.

  Subsequently, the light control surface 216 coated with the light absorption layer 220 passes through the buff 460. The buff 460 polishes the surface of the light absorption layer 220 in the traveling direction of the light control layer 210 to remove a part of the light absorption layer 220. As a result, the light absorption layer 220 is removed from the surface of the light control surface 216, as shown in the enlarged view of the cross section indicated by the dotted line D viewed from the line of sight d. On the other hand, the light absorption layer 220 remains on the light absorption surface to which the light absorption layer 220 is applied thickly.

  Thus, the light control layer 210 on which the light absorption layer 220 is formed is sequentially wound around the winding roll 470. Note that a thermosetting resin is preferably used as the resin material for forming the light absorption layer 220. Thereby, when a plasma display panel is used as the image display unit 101, the resistance of the optical member 200 to ultraviolet rays emitted from the image display unit 101 is improved.

  Note that the buffing may be wet or dry. In the above example, the light absorption layer 220 is formed by coating with the coating device 420 and partial removal with the buff 460. However, the light absorption layer 220 is formed using a bar coater such as a comma coater, a gravure coater, or a kiss coater. You can also.

  Furthermore, when buffing, the angle may be adjusted so that the light control surface 216 is perpendicular to the buff 460. Thereby, the light absorption layer 220 adhering to the light control surface 216 can be efficiently removed. In addition, when the buff 460 is polished in a direction intersecting the traveling direction of the light control surface 216, it is preferable to select a soft material for the light control layer 210. More specifically, it is preferable to select a material having a low glass transition temperature and toughness.

  FIG. 6 is a diagram schematically showing the structure of the planarization layer forming apparatus 500 used in a part of the manufacturing process of the optical member 200. The elements of the optical member 200 that have already been described are assigned the same reference numerals as those in FIGS. 1 and 2, and redundant description is omitted.

  The planarization layer forming apparatus 500 includes delivery rolls 510 and 580, a coater 540, a heater 550 and a take-up roll 570. The flattening layer forming apparatus 500 is a winding roll 510 that feeds the light control layer 210 applied by the light absorbing layer forming apparatus 400 shown in FIG. 5 and the light control layer 210 coated with the flattening layer 230. It is arranged between the take-up roll 570. The path of the light control layer 210 between the delivery roll 510 and the take-up roll 570 is defined by a plurality of guide rolls 530.

  Further, another delivery roll 580 is arranged on the opposite side of the delivery roll 510 with respect to the take-up roll 570. A separate film 250 formed of a material such as polyethylene or polypropylene, which is easily peeled off from a thermosetting resin as an adhesive described later, is wound around the delivery roll 580.

  In the planarization layer forming apparatus 500, a coater 540 is disposed immediately after the feed roll 510. The coater 540 applies a thermosetting resin diluted with a solvent, which is a material of the adhesive material, to the light control layer 210 as shown in the drawing by enlarging the portion surrounded by the dotted line D. Thereby, on the surface of the light control layer 210, the space between the flat surface 212, the light absorption surface 214, the light control surface 216, and the narrow upright surface 218 is filled with the resin to form a flat surface.

  In the planarization layer forming apparatus 500, a plurality of heaters 550 are disposed downstream of the coater 540. By evaporating the solvent with the heater 550 and curing the thermosetting resin, the thermosetting resin applied to the light control layer 210 increases the viscosity and becomes an adhesive. The light control layer 210 having the light absorption layer 220 and the flattening layer 230 is sequentially wound around the take-up roll 570 together with the separate film 250 supplied from the feed roll 580, and the long sheet-like optical member 200 is manufactured. .

  When the optical member 200 is attached to the image display unit 101, the planarizing layer 230 itself is attached to the image display unit by peeling the separate film 250. This eliminates the need for separately applying and sticking an adhesive, so that the productivity of the image display apparatus 100 can be improved. In addition, since it is not necessary to add an adhesive or the like for sticking, the image display apparatus 100 can also be made thinner.

  Note that the resin used as the light absorption layer 220 may be a resin in which a filler component is dispersed in a binder resin. As the filler component, for example, metal particles, metal oxide particles, pigments, dyes and the like can be used.

  It is preferable to select a filler component that is excellent in absorption of visible light, and examples thereof include pigments such as carbon black and titanium black. Moreover, you may use the black dye whose sunlight fastness is 5 or more. Further, from the viewpoints of dispersibility, compatibility with resins, versatility, azo black dyes can be preferably used.

  As the binder resin, acrylic resin, urethane resin, polyester resin, novolac resin, epoxy resin, nitrocellulose and the like can be used. Furthermore, you may add a hardening | curing agent, a polymerization initiator, etc. to binder resin as needed.

[Example 1]
The optical member 200 was manufactured using the apparatus shown in FIGS. 4, 5, and 6. As the substrate, a 75 μm low haze and transparent polyester film was used. In addition, there is no restriction | limiting in particular as long as adhesiveness, durability, and flexibility with an ultraviolet curable resin are good. Specifically, polycarbonate, acrylic, and polyolefin films can be used.

  As the ultraviolet curable resin, urethane acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, or the like can be used. Here, a urethane acrylate resin was selected and adjusted so that the characteristics after curing were as follows.

  Haze value of 0.3% or less (using Haze Meter HM-150 manufactured by Murakami Color Research Laboratory), total light transmittance: 90% or more (measured with the same haze meter HM-150), refractive index at room temperature: 1.54 To 1.56 (Atago Abbe refractometer DR-M2 is used at a wavelength of 589 nm), glass transition point: about 40 ° C. (dynamic viscoelasticity evaluation apparatus: calculated from tan δ peak at a measurement frequency of 1 Hz), tensile elongation : About 50% (tensile test device: dumbbell-shaped test piece, tensile speed 10 mm / min).

First, using the light control layer forming apparatus 300 shown in FIG. 4, an ultraviolet curable resin to be the light control layer 210 was applied to the base material 211 so that the thickness after application was 130 μm. A photopolymerization initiator is added to the ultraviolet curable resin. The addition amount of the photopolymerization initiator was 2 parts by weight with respect to 100 parts by weight of the resin. When ultraviolet rays were irradiated with an ultraviolet lamp 350 so that the peak illuminance was 230 mW / cm ² and the accumulated light amount was 500 mJ / cm ² , the ultraviolet curable resin was uniformly cured.

  Note that the flat surface 212, the light absorption surface 214, the light control surface 216, and the narrow upright surface 218 in the light control layer 210 were formed so that their longitudinal directions coincided with the feeding direction of the base material 211. Thereby, the embedding of the bubble to ultraviolet curable resin did not arise.

  FIG. 7 is a partial cross-sectional view showing the specifications of the light control layer 210 fabricated as described above. The angles formed by the light absorbing surface 214, the light control surface 216, and the narrow upright surface 218 are shown in the drawing.

  As shown in the drawing, the light absorbing surface 214 and the narrow upright surface 218 were formed so as to form an angle of 84 ° with respect to the flat surface 212. In order to reduce the amount by which the light absorption surface 214 blocks the light emitted from the image display unit 101, it is desirable that the angle formed by the light absorption surface 214 is 90 °, but it is difficult to release from the rotating mold 360. Therefore, an inclination of 6 ° was given.

  Other specifications are as described below. The thickness (T) of the substrate 211 is 75 μm, the thickness of the blank layer (not shown) is 25 μm, the height (H) of the light absorption surface 214 is 125 μm, and the pitch P (the distance between the tips of the light absorption surfaces 214). Was 100 μm.

  Next, the light absorption layer 220 was applied using the light absorption layer forming apparatus 400 shown in FIG. The material of the light absorption layer 220 was prepared as follows. Carbon black is added to a mixed solvent of propylene glycol monobutyl cellosolve and cyclohexanone so as to be 7% by weight with respect to the total solid weight, followed by stirring, and then 100 parts by weight of a polyester resin is further added and dispersed uniformly. Until stirred.

  Carbon black had an average particle diameter of 100 nm. Further, a leveling agent was appropriately added for the purpose of improving the wettability between the light absorbing surface 214 of the light control layer 210 and the black resin. The viscosity of the black resin was adjusted with a mixed solvent and adjusted to 500 mPa · s at room temperature. At the time of coating, the black resin was heated to about 40 ° C., and the coating device 420 was adjusted so that the coated black resin had a thickness of 3 to 5 μm after drying.

  Subsequently, the planarizing layer 230 was formed using the planarizing layer forming apparatus 500 shown in FIG. As the material of the planarizing layer 230, a material having adhesiveness, 0.04 lower than the refractive index of the light control layer 210, and a room temperature refractive index of 1.50 (wavelength 589 nm) was selected. The solid concentration contained in the planarization layer 230 was 70%.

  Examples of the resin that has adhesiveness and becomes the material of the planarizing layer 230 include a silicone resin and an acrylic resin. Here, the viscosity was adjusted to 1500 mPa · s using an acrylic resin as a main ingredient and a mixed solvent of troll and ethyl acetate. Note that the planarizing layer 230 may have a self-adhesive function that allows easy re-peeling while having adhesiveness.

An additive may be added to the planarizing layer 230 for the purpose of adjusting the refractive index. For example, when the refractive index of the planarizing layer is lowered, a fluororesin, a silicone resin, a hollow silica filler, or the like can be added. Further, when the refractive index of the planarizing layer 230 is increased, a filler, monomer, or oligomer of a metal oxide such as SnO ₂ , ITO, ZrO ₂ can be used.

  Furthermore, for the purpose of improving light resistance and durability, 5 parts by weight of an ultraviolet absorber and 0.5 parts by weight of a heat stabilizer are added to the material of the planarizing layer 230 and mixed and stirred. did. Furthermore, you may add a silane coupling agent in order to improve adhesiveness with a to-be-adhered body.

  Further, a catalyst deactivator may be added for the purpose of suppressing catalyst deterioration due to contact with metals. More specifically, “Irganox MD1024” can be exemplified. Further, a transparent conductive material having peeling charge prevention and electromagnetic wave shielding characteristics may be added.

  The material was applied from a coater 540 having a gap of 200 μm, and the thickness after drying was applied on the light control layer 210 to be at least 5 μm or more. Thereby, the optical member 200 can be smoothly attached to the image display unit 101 without directly contacting the light control layer 210.

  Thereafter, the heater 550 was heated at 70 ° C. for 2 minutes, and further heated at 100 ° C. for 2 minutes to evaporate and dry the solvent of the applied material. Furthermore, the protective film which carried out the mold release process was affixed on the dried planarization layer 230, and it cured for 24 hours. Thus, an optical member 200 having the layer structure shown in FIG. 2 and a total thickness of 250 μm was obtained.

An image display device 100 was formed using the optical member 200, and an image was displayed indoors to evaluate the effect of improving contrast. The contrast is a state in which illumination light from a fluorescent lamp is incident on the surface of the optical member 200 obliquely from above 45 ° (illuminance: horizontal direction 90 Lx of display, vertical direction 120 Lx), and a luminance meter (Topcon BM-7A, The field of view was 1 °). The image display unit 101 displayed an all-white screen and an all-black screen to measure the luminance, and the luminance value of the all-white screen was divided by the luminance of the all-black screen to obtain a contrast value. The measurement results are shown in Table 1 below.

  Further, the viewing angle and the external light absorption angle θ of the image display device 100 were measured. The viewing angle was measured using a goniophotometer (manufactured by Murakami Color Research Laboratory Co., Ltd.) by allowing diffused light to enter from the incident direction of the incident light on the display. Further, diffused light was incident from the observer 99 side, and the range of the external light absorption angle θ was measured. The measurement results are also shown in Table 1.

  FIG. 8 is a photomicrograph showing a partially enlarged cross section of the optical member 200 manufactured as described above. Elements that are the same as those in the other drawings are given the same reference numerals, and redundant descriptions are omitted.

  As shown in the drawing, a part of the light absorption layer 220 enters a region surrounded by the lower end of the light absorption surface 214, the flat surface 212, and the narrow upright surface 218.

  That is, the excess material of the light absorption layer 220 flows into the flat surface 212, thereby preventing the light absorption layer 220 from spreading on the light control surface 216. Thereby, adhesion of the material of the light absorption layer 220 can be prevented and the light control surface 216 can be kept transparent, and the original characteristics of the optical member 200 can be reliably realized.

  Moreover, since an excess material is hold | maintained at the flat surface 212, the material of the optical member 200 light absorption layer 220 can be apply | coated stably. Thereby, productivity of an optical member can be improved.

  Further, due to the presence of the flat surface 212, even if the pitch of the light absorption surface 214 and the light control surface 216 is reduced, unevenness of the light absorption layer 220 hardly occurs. Therefore, the high-definition optical member 200 can be manufactured, which contributes to the higher resolution of the image display apparatus 100.

  However, the flat surface 212 also blocks outgoing light emitted from the image display unit 101 toward the observer 99. Therefore, when the ratio of the area occupied by the flat surface 212 to the total area of the image observed through the optical member 200 exceeds 30%, the transmittance of the optical member 200 is significantly reduced. On the other hand, when the flat surface 212 becomes narrow, the capacity for receiving the surplus light absorption layer 220 is insufficient, and the effect of suppressing the occurrence of uneven coating of the light absorption layer 220 cannot be obtained. Therefore, the ratio of the area occupied by the flat surface 212 to the total area of the image observed through the optical member 200 is preferably 10% or more and 30% or less. In other words, the width G of the flat surface 212 is desirably 10% or more and 30% or less with respect to the period (pitch P) of the cross-sectional shape of the light control layer 210 illustrated in FIG.

  Note that the bottom of the belt-like flat surface 212 may be roughened for the purpose of reducing the influence of the flat surface 212 coated with the light absorbing layer 220 on the display image. Thereby, the incident light which entered from the observer 99 side can be scattered, and the apparent contrast fall can be suppressed.

  In order to make the effect of roughening the bottom of the flat surface 212 effective, it is desirable that the average surface roughness Ra of the bottom of the flat surface 212 be 1 μm or more and 5 μm or less. When the average surface roughness Ra of the flat surface 212 is less than 1 μm, the observer 99 cannot visually recognize the effect of roughening. In addition, when the average surface roughness Ra exceeds 5 μm, the variation in reflectance is visually recognized by the observer 99, so that the quality of the display image is deteriorated.

  As shown in the figure, good measurement results were obtained in all cases. The amount of transmitted light and the absorption angle range of external light are the angles of the light absorption surface 214 and the light control surface 216 of the light control layer 210, the refractive index difference between the light control layer 210 and the planarization layer 230, and the width (width G) of the flat surface 212. Can be changed by adjusting (see FIG. 7).

  In addition, when the inclination of the narrow standing surface 218 is strong, the width of the flat surface 212 when viewed from the observer 99 side changes depending on the amount of the light absorption layer 220 that has flowed into the flat surface 212. For this reason, the display image may be uneven. Therefore, the angle of the narrow upright surface 218 is also preferably equal to or close to the right angle with the light absorbing surface 214. In addition, when applying the resin that becomes the light absorption layer 220, excess resin flows into the space formed by the narrow upright surface 218, the flat surface 212, and the light absorption surface 214, and hardly adheres to other regions. There is also an effect.

  FIG. 9 is a graph showing the influence of the difference in the refractive index of the member on the characteristics of the optical member 200. As illustrated, the optical member 200 absorbs more incident light having a large incident angle with respect to the screen. Further, in Example 1 and Example 2 in which the refractive index difference Δn is given between the light control layer 210 and the planarization layer 230, the incident light is in the region from 40 ° to 60 ° above the screen indicated by the symbol F in the drawing. It can be seen that it is absorbed more efficiently. Furthermore, it can be seen that the absorption efficiency is improved when the refractive index difference Δn is large.

[Example 2]
The dimensional specification was the same as in Example 1, and an optical member 200 was produced in which the difference between the refractive index of the light control layer 210 and the refractive index of the planarization layer 230 was 0.02. The material and manufacturing method of each layer were the same as in Example 1. The image display device 100 was formed using the produced optical member 200, and the contrast and the like were evaluated by the same method as in Example 1. The evaluation results are shown in Table 1 and FIG.

  As shown in Table 1, since the external light absorption angle θ is smaller than that of the first embodiment, the contrast value is relatively low. However, it can be seen that the contrast is improved as compared with the image display device 100 that does not include the optical member 200 described in the reference.

Thus, from the viewpoint of improving contrast, the refractive index n ₂ of the material of the light control layer 210 is preferably higher than the refractive index n ₁ of the planarizing layer 230. Further, as described with reference to FIG. 3, the refractive index difference Δn between the light control layer 210 and the planarization layer 230 is set so that the incident lights L ₂₀ and L ₃₀ cause total reflection on the light control surface 216. By increasing the value, the external light absorption angle θ can be further increased. This is also shown in the measurement results shown in FIG.

  Note that the refractive index of the planarization layer 230 is preferably 0.99 times or less and 0.9 times or more that of the light control layer 210. More preferably, it is more preferably 0.99 times or less and 0.96 times or more. Thereby, when the difference in refractive index is smaller than this range, a significant effect of improving the contrast does not appear. On the other hand, when the difference in refractive index exceeds this range, the influence of other optical phenomena such as image shift cannot be ignored.

[Example 3]
The optical member 200 in which the dimensional specifications were the same as those in Example 1 and Example 2 and the refractive index of the light control layer 210 and the refractive index of the planarizing layer 230 were made the same was produced. The material and manufacturing method of each layer were the same as in Example 1 and Example 2 except that the planarizing layer 230 was formed of the same ultraviolet curable resin as that of the light control layer 210. The image display device 100 was formed using the manufactured optical member 200, and the contrast and the like were evaluated by the same method as in Example 1 and Example 2. The evaluation results are shown in Table 1 and FIG.

  As shown in Table 1, since total reflection does not occur on the light control surface 216, the external light absorption angle θ is smaller than that of the second embodiment. For this reason, the contrast value is relatively low.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  In addition, the execution order of each process such as operation, procedure, and stage in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior”. It should be noted that the output of the previous process is not explicitly stated as such, and can be realized in any order unless used in a subsequent process. Concerning the operation flow in the claims, the description, and the drawings, even if “first”, “next” and the like are described for convenience, it does not mean that the operation is essential in this order.

98 Illuminator, 99 observer, 100 image display device, 101 image display unit, 110 surface light source, 120, 140 transparent substrate, 130 image generation unit, 200 optical member, 210 light control layer, 211 base material, 212 flat surface, 214 Light absorption surface, 216 Light control surface, 218 Narrow standing surface, 220 Light absorption layer, 230 Planarization layer, 240 Surface protective layer, 250 Separate film, 300 Light control layer forming device, 310, 410, 510, 580 Delivery roll 330, 430, 530 Guide roll, 340, 540 Coater, 350 UV lamp, 360 Rotating mold, 370, 470, 570 Winding roll, 400 Light absorbing layer forming device, 420 Coating device, 440 Heater, 460 Buff, 550 Heater, 500 flattening layer forming apparatus

Claims (10)

A plurality of strip-like flat surfaces that extend in one direction and are arranged in other directions intersecting the one direction to absorb light;
In each of the plurality of strip-shaped flat surfaces, a light absorption surface that absorbs light rising from one edge facing the other adjacent strip-shaped flat surface;
In each of the plurality of strip-like flat surfaces, standing up from the other edge facing the other adjacent strip-like flat surface, a narrow standing surface narrower than the light absorption surface,
A light control surface for controlling a propagation direction of incident light while connecting a tip of the light absorbing surface and a tip of the narrow standing surface between each of the plurality of belt-like flat surfaces. The width in each of the other directions is an optical member that is narrower than the distance between the light absorption surface and the light control surface coupled to one light control surface. In a plane orthogonal to the one direction,
The width of one of the plurality of belt-like flat surfaces is a width of the belt-like flat surface,
The value of 10% or more and 30% or less with respect to the sum of the distance between the opposite edges of the other flat belt-like surface adjacent to the flat belt-like surface and the flat surface and the width. Optical member.   3. The optical member according to claim 1, wherein the plurality of belt-like flat surfaces have an average surface roughness Ra of 1 μm or more and 5 μm or less on a surface that reflects incident light.   The flattening layer which fills between the plurality of strip-like flat surfaces, the light absorption surface, the narrow upright surface, and the light control surface to form a flat surface on the optical member is further provided. The optical member according to any one of 3 to 3.   The optical member according to claim 4, wherein the planarizing layer has a thickness of 5 μm or more from an intersection line of the light control surface and the light absorption surface adjacent to each other to the surface.   The said planarization layer has a refractive index smaller than the refractive index of the material which makes the said some strip | belt-shaped flat surface, the said light absorption surface, the said narrow standing surface, and the said light control surface. Optical member.   The optical member according to claim 6, wherein the planarizing layer has a refractive index of 0.99 times or less and 0.9 times or more of the refractive index of the material.   The optical member according to any one of claims 1 to 7, wherein the light control surface has an inclination that forms a reflection angle at which the reflected light does not return to the incident light incident side. An optical member according to any one of claims 1 to 8,
An image display device comprising: an image display unit affixed to the optical member on a side where the light absorption surface stands up with respect to the plurality of belt-like flat surfaces. A plurality of strip-like flat surfaces extending in one direction and arranged in other directions intersecting the one direction to absorb light;
In each of the plurality of belt-like flat surfaces, a light absorbing surface that absorbs light rising from one edge facing the other belt-like flat surface adjacent thereto,
A narrow standing surface that is narrower than the light-absorbing surface and rises from the other edge facing the other belt-like flat surface adjacent to each other in the plurality of belt-like flat surfaces; and
A light control surface for controlling a propagation direction of incident light while connecting a tip of the light absorbing surface and a tip of the narrow upright surface between each of the plurality of belt-like flat surfaces, Forming a substrate whose width in each of the other directions is narrower than an interval between the light absorption surface and the light control surface connected to one light control surface;
Applying a light absorbing layer to the plurality of belt-like flat surfaces and the light absorbing surface of the base material.