JP2008233824A - Viewing angle control sheet and liquid crystal display using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a viewing angle control sheet that exhibits superior viewing angle control effect and facilitates handling, even if it is incorporated in a liquid crystal display, thereby improving the working efficiency in manufacturing the liquid crystal display. <P>SOLUTION: The viewing angle control sheet 10 controls a viewing angle, by which the light from a light source 15 is observed by a viewer 100 being in the opposite direction to the light source 15, by arranging the sheet between the light source 15 and a liquid crystal cell 11, and by supplying the light to the liquid crystal cell 11, while the direction of the light is controlled. A plurality of trapezoid unit lenses 16a, the tips of which are directed to the light source 15 are arranged at predetermined intervals and white light-reflecting materials are filled so as to fill in a gap 13 between the unit lenses 16a adjacent to each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical member for a liquid crystal display device, which is generally provided between a light source and a liquid crystal element, and relates to a viewing angle control sheet and a liquid crystal display device for reducing luminance improvement and luminance unevenness. The present invention relates to a viewing angle control sheet having a superior light control effect and a liquid crystal display device using the same, which can reduce the material cost compared to a conventional viewing angle control sheet.

  2. Description of the Related Art Conventionally, in a liquid crystal display device, a viewing angle control sheet is generally provided between a light source and a liquid crystal element to improve luminance and reduce luminance unevenness.

  In this type of viewing angle control sheet, for example, a sheet in which triangular prisms are continuously arranged is widely used, which is independent of the light diffusion layer. Light from the light source is scattered by a plurality of stacked high-haze light diffusion plates and light diffusion films, and brightness unevenness is alleviated. Then, the light enters the plane side (non-prism surface) of the prism sheet, and is reflected by the slope of the prism. The light is refracted and emitted toward the liquid crystal element. At this time, depending on the incident angle, the light from the light source is totally reflected by the prism surface, returns once to the light source, retroreflects, and enters the prism sheet again. By repeating this, the angle of light passing through to the front is controlled. An example of such a viewing angle control sheet is disclosed in Patent Document 1, but since it is not integrated with the light diffusion layer, it is not always handled when a liquid crystal display device is manufactured by incorporating this viewing angle control sheet. It's not easy.

On the other hand, as shown in Patent Document 2, there is a viewing angle control sheet that can be integrated with a light diffusion layer and uses a difference in refractive index between a lens portion and a non-lens portion. In this type of viewing angle control sheet, the incident light is totally reflected at the boundary of the lens unit due to the difference in refractive index, thereby controlling the light transmitted through the viewing angle control sheet to face the front, There is also a configuration in which light that is emitted at a steep angle other than light that passes through the front surface is removed by filling the lens portion with a light absorbing material. In such a viewing angle control sheet, when a light absorbing material is used, the total light transmittance is lowered and the screen becomes dark overall.
U.S. Pat. No. 4,662,728 JP 2006-343711 A

  However, such a conventional viewing angle control sheet has the following problems.

  That is, as disclosed in Patent Document 1, in the configuration that is not integrated with the light diffusion layer, there is a problem that it is not always easy to handle when manufacturing a liquid crystal display device incorporating this viewing angle control sheet. However, the configuration of the viewing angle control sheet itself is simple and requires less material.

  On the other hand, as disclosed in Patent Document 2, the viewing angle control sheet that can be integrated with the light diffusing layer uses the difference in the refractive index of the member, so the number of types of resin handled increases, and the number of exposures As a result, the number of work processes increases and the manufacturing cost increases significantly. In addition, when a large amount of resin is used, yellowing is conspicuous due to strong light from the light source, so that the performance of the viewing angle control sheet is likely to be deteriorated.

  The present invention has been made in view of such circumstances, exhibits an excellent viewing angle control effect, and is easy to handle even when incorporated in a liquid crystal display device. An object of the present invention is to provide a viewing angle control sheet capable of improving the working efficiency and a liquid crystal display device using the same.

  In order to achieve the above object, the present invention takes the following measures.

  That is, the invention according to claim 1 is provided between the light source and the liquid crystal element, and supplies light to the liquid crystal element while controlling the direction of light from the light source, so that light is observed by an observer in the direction opposite to the light source side. Is a viewing angle control sheet for controlling the viewing angle, wherein a plurality of trapezoidal unit lenses whose front ends face the light source are arranged at a predetermined interval, and a gap between adjacent unit lenses is formed. The viewing angle control sheet is filled with a white light reflecting material so as to be buried.

The invention according to claim 2 is provided between the light source and the liquid crystal element, and is supplied to the liquid crystal element while controlling the direction of the light from the light source, so that the light is observed by an observer in the direction opposite to the light source side. A plurality of trapezoidal unit lenses whose front ends face the light source are arranged at a predetermined interval, and air is supplied to the gap between adjacent unit lenses. 3. The viewing angle control sheet according to claim 2, wherein the light source side of the gap is provided with a light reflective metal film or a white light reflecting material. It is a viewing angle control sheet.

  According to a fourth aspect of the present invention, the gap has a substantially isosceles triangle shape, a substantially abutment trapezoidal shape, a substantially isosceles triangle or a substantially isosceles leg having a different angle of the hypotenuse in the cross section along the thickness direction of the viewing angle control sheet 4. The device according to claim 1, wherein the shape is formed by connecting two or more trapezoids, or a shape having a curvature of either a circumscribed circle or an inscribed circle on a hypotenuse. The viewing angle control sheet according to item.

  The invention according to claim 5 is characterized in that the gap in the cross section along the thickness direction of the viewing angle control sheet has an asymmetrical isosceles triangle shape, an asymmetrical trapezoidal shape, and an asymmetrical isosceles triangle shape having different oblique sides. Or any one of a shape formed by connecting two or more trapezoids, and a shape having a curvature of either a circumscribed circle or an inscribed circle on the hypotenuse. The viewing angle control sheet according to Item 1.

  The invention according to claim 6 is the viewing angle control sheet according to any one of claims 1 to 5, wherein at least one light diffusion layer is provided on the observer side or the light source side. .

  The invention according to claim 7 is the viewing angle control sheet according to any one of claims 1 to 6, wherein the viewing angle control sheet is bonded to a liquid crystal element.

  The invention according to claim 8 includes a first base material provided on the viewer side and a second base material provided on the light source side, and includes a refractive index n1 of the first base material and a unit lens. The relationship of n1> n2≈n3 or n1≈n2> n3 is established between the refractive index n2 of the included portion and the refractive index n3 of the second substrate. It is a viewing angle control sheet | seat of any one.

  According to the ninth aspect of the present invention, at least one of a layer for preventing light reflection, a layer for preventing light glare, and a layer for preventing charging, or a touch sensor is further provided on the viewer side or the light source side. The viewing angle control sheet according to claim 1, wherein the viewing angle control sheet is provided.

  A tenth aspect of the present invention is a liquid crystal display device comprising the viewing angle control sheet according to any one of the first to ninth aspects.

  An eleventh aspect of the invention is the liquid crystal display device according to the tenth aspect, further comprising a light reflection layer that reflects light from the light source toward the viewer on the non-observer side of the light source.

  According to the present invention, an excellent viewing angle control effect is exhibited, and even when incorporated in a liquid crystal display device, it is easy to handle and it is possible to improve work efficiency when manufacturing the liquid crystal display device. A viewing angle control sheet and a liquid crystal display device using the same can be realized.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Configuration example of viewing angle control sheet)
The viewing angle control sheet 10 according to the embodiment of the present invention is provided between the light source 15 and the liquid crystal element 11 as shown in a cross-sectional view along the sheet thickness direction (vertical direction in the drawing) of FIG. By supplying to the liquid crystal element 11 while controlling the direction of light from the light source 15, the viewing angle at which light is observed by the observer 100 in the direction opposite to the light source 15 side is controlled. In this viewing angle control sheet 10, a plurality of trapezoidal unit lenses 16a whose front ends face the light source 15 are arranged at a predetermined interval P, and white so as to fill the gap 13 between adjacent unit lenses 16a. Filled with light reflecting material. Moreover, the base material 12 and the base material 14 are provided as needed as described below, and are not necessarily indispensable elements.

  The base material 12 and the base material 14 are selectively used depending on the case. Depending on the configuration, only the base material 12 or only the base material 14 may be used. For example, when considering actual molding, the base materials 12 and 14 may be unnecessary if they are extrusion molding. However, for example, when a UV curable resin is injected onto a mold and cured and molded, at least one of the base materials 12 and 14 is indispensable. Depending on the shape of the mold and the production order, the position where the base material should be provided is above the lens portion 16 (base material 12) or below the lens portion 16 (base material 14). Further, as described later, by providing a material having a refractive index different from the refractive index of the lens portion 16 as the base materials 12 and 14, the light control effect can be further enhanced. In addition, the material of the base material, the number of sheets, and the position to be provided are selected according to the purpose, such as strengthening the sheet resistance or adding an ultraviolet absorption effect. Thus, the base material is properly used depending on the situation. An example of the material is a PET film.

The base materials 12 and 14 may act as a light diffusion layer, and it is necessary to transmit incident light while scattering it. For this reason, the average particle diameter of the transparent particles contained in the light diffusion layer is desirably 0.5 to 10.0 μm (where 1 μm = 1 × 10 ⁻⁶ m). Preferably it is 1.0-5.0 micrometers.

  As the transparent resin, for example, polycarbonate resin, acrylic resin, fluorine acrylic resin, silicone acrylic resin, epoxy acrylate resin, methylstyrene resin, fluorene resin, and the like can be used.

  Moreover, as transparent particles, transparent particles made of inorganic oxide or transparent particles made of resin can be used. For example, examples of the transparent particles made of an inorganic oxide include particles made of silica, alumina or the like. The transparent particles made of resin include acrylic particles, styrene particles, styrene acrylic particles and cross-linked products thereof; melamine-formalin condensate particles; PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy resin), FEP (tetra Fluoropolymer particles such as fluoroethylene-hexafluoropropylene copolymer), PVDF (polyfluorovinylidene), and ETFE (ethylene-tetrafluoroethylene copolymer); silicone resin particles and the like. These transparent particles may be used as a mixture of two or more.

And the plate-shaped base materials 12 and 14 can be manufactured by disperse | distributing transparent particles in these transparent resins, and extrusion-molding. Moreover, when the base materials 12 and 14 are bonded to other base materials, the expansion coefficient of the base materials 12 and 14 is normal temperature and the linear expansion coefficient is 4.0 × 10 ^{− 5} cm / cm / ° C. to 1.0 × 10 ⁻⁴ cm / cm / ° C. is desirable.

  As the white light reflecting material, it is preferable to select a white light-reflecting material using a white pigment and a metal vapor-deposited layer and having high light reflectance and low light absorption. Examples of the white pigment include titanium dioxide, barium sulfate, and magnesium oxide, which are well known in the technical field. Examples of the white pigment include mixing these with a binder resin to obtain ink. Alternatively, air may be filled instead of filling the white light reflecting material.

  By filling the gap 13 with the white light reflecting material, the light can be totally reflected more efficiently than when the resin having a different refractive index is filled, and the total light transmittance is improved due to less light absorption. It leads to improvement. Depending on the material used for the lens portion 16 that is a part including the unit lens 16a, the use of a white pigment other than titanium dioxide that acts as a photocatalyst may increase the resistance.

  As the material of the lens portion 16, a thermoplastic resin material such as an acrylic resin, a polycarbonate resin, a styrene resin, an acrylic / styrene copolymer resin, or an inorganic material containing silicate as a component may be used. it can. It is essential that all materials have high light transmittance. The lens unit 16 is manufactured by applying or injecting an ionizing radiation resin such as an ultraviolet curable resin (UV resin) or an electron beam curable resin onto the unevenness forming surface of a press method, a casting method, or a flat stamper or roll stamper. It can be obtained by a method in which a base material is arranged on the top, and after the curing treatment, is released from the stamper.

  On the other hand, when the gap 13 is filled with air, the refractive index of the air filled in the gap 13 is approximately 1, and a low refractive index can be realized without using a material such as a resin. The light can be totally reflected. In addition, it is possible to save the trouble of filling a resin having a different refractive index and curing it again by exposure or the like, so that the manufacturing cost can be reduced.

(Another configuration example of the viewing angle control sheet)
Another configuration example of the viewing angle control sheet 20 is shown in FIG. In the viewing angle control sheet 20 shown in FIG. 2, the same parts as those in the viewing angle control sheet 10 shown in FIG. As shown in FIG. 2, the viewing angle control sheet 20 has a function of reflecting light on the light source 15 side surface 13a of the gap 13 filled with air of the viewing angle control sheet 10 shown in FIG. The layer 17 is arranged.

  The light reflecting layer 17 is made of a highly light reflecting metal film or the above-described white light reflecting material. Specifically, the light reflecting layer 17 is a highly light reflective metal film typified by silver or aluminum, titanium dioxide, barium sulfate, and magnesium oxide. As an example, a white pigment typified by the above or the like is mixed with a binder resin to form an ink.

  In the case of air having a refractive index n2 (= 1) and a refractive index n3 of the substrate 14, the incident angle of the light from the light source 15 on the substrate 14 is Asin (n3 × sin (Asin (n2 / n3))) Smaller light that reaches the air layer in the gap 13 may enter the gap 13 without being totally reflected at the boundary between the gap 13 and the substrate 14. Therefore, providing the light reflecting layer 17 on the surface 13a of the gap 13 on the light source 15 side has an effect of suppressing light penetration into the air layer of the gap 13 and increasing the light transmittance.

(Gap shape)
Next, the shape of the gap 13 will be described. The shape of the gap 13 described here applies in common to any of the two viewing angle control sheets 10 and 20 described above.

  The gap 13 has a shape in a cross section along the thickness direction of the viewing angle control sheets 10 and 20 that is substantially isosceles triangle A, substantially abutment trapezoid shape B, a substantially isosceles triangle or a substantially isosceles trapezoid with different oblique sides. Is a shape formed by connecting two or more of them, or a shape having a curvature of either a circumscribed circle or an inscribed circle on the hypotenuse. FIG. 3A shows an example of a shape formed by sequentially connecting a substantially isosceles triangle A, a substantially trapezoid trapezoid B1, and a substantially trapezoid trapezoid B2. FIG. 3B shows an example of a shape formed by connecting two substantially trapezoidal trapezoids B3 and B4. Note that the isosceles triangle A and the trapezoid B may be left-right asymmetric. FIG. 3C shows an example of a shape E having a circumscribed circle curvature on the hypotenuse. FIG. 3D shows an example of a shape F having a curvature of an inscribed circle on the hypotenuse.

  Since the gap 13 has such a shape, in addition to the case where there is a single slope angle such as a substantially isosceles triangle and a substantially trapezoidal trapezoid, FIG. 3 (a) and FIG. 3 (b) As shown in the figure, the shape formed by connecting two or more substantially isosceles triangles A or substantially isosceles trapezoids B having different oblique sides makes it possible to further control the viewing angle by creating several different slope angles. . Further, these slopes are not flat surfaces but curved surfaces with curvatures as shown in FIGS. 3C and 3D, so that the light of the isotropic light source 15 is more uneven in luminance. It is also possible to control while suppressing.

(Other additional configurations)
A viewing angle control sheet to which another configuration is added will be described. This also applies in common to any of the two viewing angle control sheets 10 and 20 described above.

  First, the viewing angle control sheet according to the embodiment of the present invention includes at least one light diffusion layer on the surface on the viewer 100 side or the light source 15 side. FIG. 5 shows an example in which a single light diffusion layer 23 is provided on the surface on the light source 15 side. The light diffusing layer 23 is selected in consideration of optical properties such as transmittance, diffuse transmittance, and refractive index difference, surface gloss, dispersibility of the light diffusing material in the binder resin, and brittleness when molded. be able to.

  Alternatively, in addition to the light diffusion layer 23, an AR (Anti-Reflection) layer for preventing light reflection, an LR (Low Reflection) layer for preventing light reflection, on the surface on the viewer 100 side or the light source 15 side, At least one of an AG (Anti-glare) layer that prevents glare of light, an AS (Anti-static electricity) layer that prevents charging, or a touch sensor is provided.

  The AR layer and the LR layer have a role of suppressing light reflection. Although depending on the purpose, in order to prevent stray light due to light reflection between the members, an AR layer or an LR layer 41 is provided between the members as shown in FIG. 4A. When it is desired to prevent reflection of external light, the AR layer or the LR layer 41 is included in the member provided on the viewer 100 side (upper side in the figure) as shown in FIG. As shown in FIG. 4A, a light diffusion layer 40 may be further provided on the viewer 100 side of the AR layer or the LR layer 41.

  Further, as shown in FIG. 4B, the AS layer 42 having an antistatic role can be provided on the viewer 100 side, thereby improving the ease of handling of the viewing angle control sheet.

  The AG layer 43 that prevents glare of light is generally provided on the viewer 100 side. The touch sensor 44 is provided on the surface on the viewer 100 side. The arrangement example shown in FIG. 4C is an example in which the touch sensor 44 is provided closest to the viewer 100 side of the viewing angle control sheet 10 and the AG layer 43 is provided between the touch sensor 44 and the viewing angle control sheet 10. Show.

  By providing the touch sensor in this way, as will be described later, the viewing angle control sheet according to the embodiment of the present invention can be suitably applied to ATM as a peeping prevention sheet.

  Since the viewing angle control sheet according to the embodiment of the present invention can be made flat on both sides as shown in FIGS. 1 and 2, the liquid crystal element 11 is easily pasted on the surface on the viewer 100 side. Can be combined. Further, the light diffusion layer 40, the AR layer or the LR layer 41, the AS layer 42, the AG layer 43, the touch sensor 44, or the like can be easily integrated.

  The conventional viewing angle control sheet has no performance unless a separate air layer is provided between the light diffusion layer and it is difficult to integrate. However, if the shape freedom by the viewing angle control sheet according to the embodiment of the present invention and the fact that an air layer can be provided in the gap 13 are utilized, the light diffusion layer 23 depends on the situation of the light source 15 and the required specifications. Various characteristics using can be realized. Further, by integrating with the light diffusion layer 23, there is also an advantage that the ease of assembly at the time of manufacturing the liquid crystal display device is improved.

(Refractive index of substrate)
In the viewing angle control sheets 10 and 20, the base material 12 and the base material 14 are provided as necessary and are not necessarily indispensable elements as described above. Is provided between the refractive index n1 of the base material 12, the refractive index n2 of the lens portion 16, and the refractive index n3 of the base material 14,
n1> n2≈n3,
Or
n1≈n2> n3
The relationship is established.

  As described above, when the layer having the highest refractive index is provided on the viewer 100 side, there is an effect that light which is emitted at a steep angle which is not required can be totally reflected back at the boundary.

(Liquid crystal display device)
The liquid crystal display device according to the embodiment of the present invention is configured by using the viewing angle control sheet as described above. In this case, as shown in FIG. 5, a light reflection layer 51 for retroreflective use that reflects light from the light source 15 toward the viewer 100 is further provided on the non-observer side (lower side in the figure) of the light source 15. You may make it prepare. In this way, by providing the light reflection layer 51 on the back side of the light source 15, light having a steep emission angle that is not required is once returned to the light source 15 side by total reflection, and the retroreflected light is controlled again. ing.

  A behavior in which light is controlled by the viewing angle control sheet according to the embodiment of the present invention configured as described above will be described with reference to FIG.

  The viewing angle control sheet shown in FIG. 5 includes a light diffusion layer 23, a base material 14, a gap 13, a lens portion 16, and a base material 12 in order from the light source 15 side, and is a front surface for a liquid crystal display device. It is an example in the case of using for the brightness improvement. The gap 13 is filled with a white substance, and a light reflecting layer 51 is provided on the back side of the light source 15 that mainly uses a backlight in which a plurality of cold cathode fluorescent lamps are arranged. The returned light is reflected again to the viewer 100 side. Of course, the viewing angle control sheet of the present invention is not limited to the configuration shown in FIG.

  In the viewing angle control sheet having such a configuration, the light emitted from the light source 15 enters the light diffusion layer 23 and is scattered, and then passes through the base material 14. At this time, the light hitting the bottom surface of the gap 13 is totally reflected and returned to the light source 15 side because of the white substance filled in the gap 13. The returned light is totally reflected by the light reflecting layer 51 installed on the back surface of the light source 15 and travels again toward the viewer 100. On the other hand, after passing through the base material 14, the light that has not passed through the inclined surface of the gap 13 among the light that has passed through the lens unit 16 proceeds directly to the base material 12 while being refracted by the refractive index difference of each member. Light hitting the 13 slope is totally reflected by this slope. These lights travel to the substrate 12, are emitted, and travel to a liquid crystal element (not shown) disposed at the top in the drawing. The light is also controlled by the difference in refractive index between the lens unit 16 and the base material 12, the base material 14, and the light diffusion layer 23, and the light that has been scattered around the light source 15 is controlled to face the front direction, that is, the viewer 100 side. Is done.

  FIG. 6 is a characteristic diagram quantitatively showing the state in which light is controlled to face the front direction in this way. The characteristic diagram shown in FIG. 6 is a transparent UV curable resin in which the inclination of the gap 13 is 20 degrees with respect to the surface, an acrylic plate having a refractive index of 1.56 as the substrate 12, and a refractive index of 1.53 as the lens portion 16. A viewing angle control sheet formed by filling the base material 14 with a PET film having a refractive index of 1.51 and filling the gap 13 with ink mixed with titanium dioxide is used for the liquid crystal backlight as the light source 15 and the liquid crystal element 11. It is the light distribution characteristic measured about the liquid crystal display device provided in between using the liquid crystal viewing angle and chromaticity characteristic measuring device (EZcontrautXL88 by ELDIM). In the characteristic diagram shown in FIG. 6, the horizontal axis indicates the viewing angle and the vertical axis indicates the relative luminance. As shown in FIG. 6, the light intensity distribution X with the viewing angle controlled is controlled such that light is emitted from the front as compared with the light intensity distribution Y with the light source 15 (without the viewing angle control). I understand.

  The viewing angle control sheet of the present invention having such a light control function can be applied not only to a liquid crystal display device but also to a peeping prevention sheet or the like depending on the way of viewing angle control. In this case, since peeping from an oblique direction cannot be performed, the touch sensor 44 is further provided on the surface on the viewer 100 side or the light source 15 side, so that it can be suitably applied to, for example, ATM.

  As described above, the viewing angle control sheet according to the present embodiment can efficiently totally reflect the light from the light source 15 by filling the gap 13 between the adjacent unit lenses 16a with a white substance. Accordingly, it is possible to exhibit an excellent viewing angle control effect.

  In addition, when the gap 13 is filled with air, the refractive index difference between the resins is not used, so that a process such as a plurality of exposures can be cut, the manufacturing cost can be reduced, and the refractive index of the air Is a low value of 1, the angle range for total reflection of light can be widened.

  Furthermore, since the viewing angle control sheet according to the present embodiment including the lens portion 16 and the gap 13, and optionally the base material 12 and the base material 14, is smooth on both sides, it is integrated with the light diffusion layer 23. Can be realized. Therefore, even when it is incorporated in a liquid crystal display device, it is easy to handle, and the working efficiency at the time of manufacturing the liquid crystal display device can be improved.

  Furthermore, as described in (Refractive index of the base material), when the refractive index difference among the lens unit 16, the base material 12, and the base material 14 is used, the light emission side (observer 100 side) of the base material 12. If the refractive index is set high, the light directed to the front is transmitted to some extent, but tries to escape obliquely at a steep angle exceeding the critical angle determined by the refractive index difference between the base material 12 and the air on the light exit side. The light is totally reflected at this boundary, returned to the light source 15 side, retro-reflected and incident again on the lens unit 16 to control the viewing angle. In this way, only the light directed to the front can be selected, and stray light, ghost, and the like can be prevented.

  The best mode for carrying out the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such a configuration. Within the scope of the invented technical idea of the scope of claims, a person skilled in the art can conceive of various changes and modifications. The technical scope of the present invention is also applicable to these changes and modifications. It is understood that it belongs to.

Sectional drawing which shows the structural example of the viewing angle control sheet which concerns on embodiment of this invention. Sectional drawing which shows another structural example of the viewing angle control sheet which concerns on embodiment of this invention. The partial detail figure which shows the example of a shape of a clearance gap. Sectional drawing which shows the structural example of the viewing angle control sheet | seat which provided the light-diffusion layer, AR layer or LR layer, AS layer, AG layer, and the touch sensor. The conceptual diagram which shows an example of the optical path control by the viewing angle control sheet which concerns on embodiment of this invention. The characteristic view which shows an example of the viewing angle control effect by the viewing angle control sheet which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10,20 ... Viewing angle control sheet, 11 ... Liquid crystal element, 12, 14 ... Base material, 13 ... Gap, 14 ... Base material, 15 ... Light source, 16 ... Lens part, 16a ... Unit lens, 17 ... Light reflection layer, DESCRIPTION OF SYMBOLS 23 ... Light diffusion layer, 40 ... Light diffusion layer, 41 ... AR layer or LR layer, 42 ... AS layer, 43 ... AG layer, 44 ... Touch sensor, 51 ... Light reflection layer, 100 ... Observer

Claims (11)

A viewing angle that is provided between the light source and the liquid crystal element, and is supplied to the liquid crystal element while controlling the direction of the light from the light source, so that the light is observed by an observer in a direction opposite to the light source side. A viewing angle control sheet for controlling
A plurality of trapezoidal unit lenses whose front ends are directed to the light source side are arranged at a predetermined interval and filled with a white light reflecting material so as to fill a gap between adjacent unit lenses. Angle control sheet. A viewing angle that is provided between the light source and the liquid crystal element, and is supplied to the liquid crystal element while controlling the direction of the light from the light source, so that the light is observed by an observer in a direction opposite to the light source side. A viewing angle control sheet for controlling
A viewing angle control sheet in which a plurality of trapezoidal unit lenses whose front ends are directed to the light source side are arranged at a predetermined interval, and a gap between adjacent unit lenses is filled with air.   The viewing angle control sheet according to claim 2, further comprising a light reflective metal film or a white light reflecting material on the light source side of the gap.   The gap has two or more shapes in a cross section along the thickness direction of the viewing angle control sheet, that is, an approximately isosceles triangle shape, an approximately abutment trapezoid shape, an approximately isosceles triangle or an approximately isosceles trapezoid shape having different oblique sides. The shape according to any one of claims 1 to 3, wherein the shape is a shape formed by connection, or a shape having a curvature of either a circumscribed circle or an inscribed circle on the hypotenuse. Viewing angle control sheet.   The gap has two cross-sectional shapes in the thickness direction of the viewing angle control sheet: an asymmetrical isosceles triangle shape, a laterally asymmetric trapezoidal shape, a laterally asymmetric isosceles triangle with a different oblique angle, or two trapezoids. 4. The shape according to any one of claims 1 to 3, wherein the shape is a shape that can be connected as described above, or a shape that has a curvature of either a circumscribed circle or an inscribed circle on the hypotenuse. Viewing angle control sheet.   The viewing angle control sheet according to any one of claims 1 to 5, further comprising at least one light diffusion layer on the viewer side or the light source side.   The viewing angle control sheet according to any one of claims 1 to 6, wherein the viewing angle control sheet is bonded to the liquid crystal element. A first substrate provided on the observer side;
A second substrate provided on the light source side,
N1> n2≈n3 or n1≈n2> n3 between the refractive index n1 of the first base material, the refractive index n2 of the portion including the unit lens, and the refractive index n3 of the second base material The viewing angle control sheet according to claim 1, wherein the relationship is established.   Further, at least one of a layer for preventing light reflection, a layer for preventing light glare, a layer for preventing charging, or a touch sensor is further provided on the viewer side or the light source side. The viewing angle control sheet according to any one of claims 1 to 8.   A liquid crystal display device comprising the viewing angle control sheet according to claim 1.   The liquid crystal display device according to claim 10, further comprising a light reflection layer that reflects light from the light source toward the viewer side on a non-viewer side of the light source.

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