JP2007140403A - Viewing angle control sheet and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a viewing angle control sheet wherein contrast is enhanced by suppressing reduction in contrast of an image due to external light and suppressing occurrence of a ghost, reduction of luminance of a screen is suppressed by effectively utilizing diffusion light from a video source and a viewing angle is controlled in a prescribed range. <P>SOLUTION: The viewing angle control sheet is provided with a viewing angle control part 12 provided with light shielding parts 15 and a light non-shielding part 14. The light shielding parts are formed in a direction from the light receiving surface of the viewing angle control part to a viewer side and a plurality of the light shielding parts are disposed while being separated from one another in a light receiving surface direction. A plurality of light absorbing layers 21, 22,... are formed in each light shielding part at a nearly equal distance from one another in the direction from the light receiving surface to the viewer side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is installed on the front face of a display, and the display performance, in particular, a function for preventing a decrease in performance due to a decrease in contrast when external light hits the display, and a visual field by suitably diffusing the effective light of the display. The present invention relates to a viewing angle control sheet having a function of controlling an angle within an arbitrary range and a display device using the same. In the present invention, the “sheet” is a concept that includes what a person skilled in the art normally considers as a “film”.

In an organic light-emitting diode display (hereinafter referred to as OLED), a liquid crystal display (hereinafter referred to as LCD), and the like, a visual field is usually obtained so that a viewer can obtain a good image from any position. Wide corners are preferred.
On the other hand, for example, when working on a commuter train, it may be difficult to see the screen from people around you. In such a case, it will be visible only to the viewer of the display and not to others. Control of the viewing angle is desired. In response to such a demand, for example, a louver type viewing angle control sheet as shown in FIG. 11 has been developed and used. The louver type viewing angle control sheet has an effect of increasing the contrast by blocking outside light, and for example, a viewing angle control sheet is disclosed in which occurrence of a double image (referred to as a ghost) in the louver is reduced. (See Patent Document 1 to Patent Document 3.) FIG. 5 of Patent Document 1 describes an illustration of a ghost.
Japanese Patent Publication No.58-47681 JP-T 6-504627 JP-A-9-311206

  However, the conventional louver-type viewing angle control sheet described in Patent Documents 1 to 3 simply cuts the image light in an oblique direction, and in a display such as a high-definition LCD, the viewer side There is a problem in that the diffused light of the diffused light source on the video side to be reached is reduced and the brightness of the screen is lowered.

  Therefore, the present invention suppresses a decrease in image contrast due to external light, suppresses the occurrence of ghosts, improves the contrast, and effectively uses diffused light from a video source to suppress a decrease in screen brightness. Another object of the present invention is to provide a viewing angle control sheet having a function of controlling the viewing angle within an arbitrary range.

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

  The invention according to claim 1 includes a viewing angle control unit (12) including a light shielding unit (15) and a non-light shielding unit (14), and the light shielding unit is directed from the light receiving surface of the viewing angle control unit toward the viewer. A plurality of light shielding layers are arranged in the light receiving surface direction, and a light absorbing layer (21, 22,...) Is formed on each light shielding portion at a substantially equal distance from the light receiving surface in the observer direction. An object of the present invention is to solve the above problem by a viewing angle control sheet characterized in that a plurality of light absorbing layers are provided in each light shielding portion. Note that, as described above, the “sheet” in the present invention includes what is considered as “film” by those skilled in the art. The same applies to the following.

The invention according to claim 2 is the viewing angle control sheet according to claim 1, wherein R is the total area of the light absorption layers (21, 22,...) Closest to the light receiving surface, and the area of the entire light receiving surface. When S is
0.1 <R / S <0.4
The relationship is established.

  According to a third aspect of the present invention, in the viewing angle control sheet (10) according to the first or second aspect, the light shielding portion (15) has a wedge shape that gradually becomes narrower from the light receiving surface toward the observer. Features.

According to a fourth aspect of the present invention, in the viewing angle control sheet (10) according to the third aspect, the light shielding portion (15) is a transparent portion disposed between the light absorbing layer (21, 22, ...) and the light absorbing layer. (16), the refractive index of the material constituting the transparent portion is Nx, and the refractive index of the material constituting the non-light-shielding portion is Ny,
Nx ≦ Ny
The relationship is established.

According to a fifth aspect of the present invention, in the viewing angle control sheet (10) according to the third or fourth aspect, the angle formed by the wedge-shaped slope portion and the normal line of the light exit surface is θ and Nx / Ny = Δn. When
−0.01 <Δn−cos θ <0.002
The relationship is established.

The invention according to claim 6 is the viewing angle control sheet (10) according to any one of claims 3 to 5, wherein the width of the light absorption layer (21) closest to the light receiving surface in each light shielding portion (15) is set. W, when D is the length from the light absorption layer closest to the light receiving surface to the portion of the light shielding portion closest to the observer,
W ≦ D ≦ 15W
The relationship is established.

A seventh aspect of the present invention is the viewing angle control sheet according to any one of the third to sixth aspects, wherein the light on the light receiving surface side of the light absorbing layers adjacent to each other in each light shielding portion (15). The width of the absorption layer is W _i , the width of the light absorption layer on the viewer side is W _{i + 1} , and the distance between the two light absorption layers is d _i
And when
tan ⁻¹ (2d _i / (W _i + W _{i + 1} ))> sin ⁻¹ (Ny / Nx) −θ
The relationship is established.

  According to an eighth aspect of the present invention, in the viewing angle control sheet (10) according to any one of the third to seventh aspects, the light-shielding portion (15) includes a photosensitive adhesive layer patterning and a light absorption layer (21). , 22,...) Is repeatedly formed.

  The invention described in claim 9 is characterized in that, in the viewing angle control sheet (10) according to claim 8, a lenticular lens (81) is used for patterning.

  According to a tenth aspect of the present invention, the viewing angle control sheet (10) according to any one of the first to ninth aspects is laminated on the viewer side of the image source, or two sheets are laminated substantially orthogonally. It is characterized by being.

  Invention of Claim 11 WHEREIN: In the viewing angle control sheet | seat (10) of any one of Claims 1-10, any one of AR, AS, AG, and a touch sensor in at least one surface side, Alternatively, a plurality of these additional functions are given.

  The invention described in claim 12 is a display device (100), characterized in that the viewing angle control sheet according to any one of claims 1 to 11 is adhered.

  According to the present invention, the light shielding portions are arranged at a predetermined interval, and a plurality of light absorption layers parallel to the light receiving surface are formed at intervals within each light shielding portion. Preferably, the refractive index of the substance constituting the non-light-shielding part around the light-shielding part having a wedge-shaped cross section is formed to be higher than the refractive index of the substance constituting the light-shielding part. With this configuration, according to the viewing angle control sheet of the present invention, it is possible to suppress a decrease in contrast of an image due to external light and to suppress the occurrence of ghost. Further, according to the viewing angle control sheet of the present invention, it is possible to obtain a viewing angle control sheet in which the diffused light from the image source is effectively used to suppress a decrease in screen brightness and the viewing angle is controlled within a predetermined range. it can.

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

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

FIG. 1 is a view showing a cross section of a viewing angle control sheet according to the present invention by a plane perpendicular to the light receiving surface. In FIG. 1, an image light source is arranged on the upper side of the drawing to emit diffused light, and an observer is located on the lower side of the drawing. The illustrated viewing angle control sheet 10 is formed by laminating an image source side base sheet 11, a viewing angle control unit 12, and an observer side base sheet 13 in order from the image source side to the observer direction. The viewing angle control unit 12 includes a non-light-shielding part 14 and a plurality of light-shielding parts 15, 15, 15... Arranged at a predetermined interval. Each light shielding portion 15 has a wide portion on the light receiving surface of the viewing angle control portion 12 and has a wedge shape that becomes gradually narrower in the observer direction. On the image source side surface of the viewing angle control unit 12, that is, the light receiving surface, the wedge-shaped bottom surface portion of the light shielding portion 15 and the non-light shielding portions 14 are alternately arranged. When the total area of the bottom surface portion on the light receiving surface is R and the area of the entire light receiving surface is S, it is preferable that the following relational expression is satisfied with respect to the aperture ratio (R / S) of the light shielding portion.
0.1 <R / S <0.4
By limiting the aperture ratio to such a range, it is possible to suppress a decrease in contrast and luminance while controlling the viewing angle.

  The image source side base sheet 11 and the observer side base sheet 13 are made of a material having substantially the same refractive index as that of the non-light-shielding portion 14. The outer side surface of the observer-side base sheet 13 has at least one function among AR, AS, AG, and touch sensor on the observer side. Here, “AR” is an abbreviation for anti-reflection, and refers to a function of suppressing the reflectance of light incident on the lens surface. “AS” is an abbreviation for anti-static and refers to an antistatic function. “AG” is an abbreviation for anti-glare and refers to the anti-glare function of the lens. The viewing angle control sheet 10 according to the present embodiment may have only one of these functions, or may have a plurality of functions.

FIG. 2 is a diagram showing light transmission and blocking by the viewing angle control sheet 10 of the present invention. In the drawing, the display of the image source side base sheet 11 and the observer side base sheet 13 is omitted, and only the viewing angle control unit 12 is shown. The viewing angle control unit 12 shown in the figure is arranged as if two light shielding units 15, 15 adjacent to each other are embedded above the non-light shielding unit 14. The non-light-shielding part 14 is made of a material having a refractive index of Ny. On the other hand, in the light shielding portion 15, transparent portions 16, 16,... Are arranged between light absorbing layers 21, 22,. The transparent portion 16 is filled with a material having a refractive index of Nx. Where Nx ≦ Ny
It is preferable that The ratio between the refractive index Ny and the refractive index Nx is set within a predetermined range in order to obtain the optical characteristics of the viewing angle control sheet 10. Further, the angle between the inclined surface where the light shielding portion 15 and the non-light shielding portion 14 are in contact with the normal H of the light receiving surface (a line parallel to the perpendicular incident light with respect to the viewing angle control sheet 10) is formed at a predetermined angle θ. Yes.

  In each light shielding portion 15, a plurality of light absorption layers 21, 22,... Are formed in parallel to the light receiving surface in the wedge-shaped tip direction. The light absorbing layers 21, 22,... Are formed of, for example, a carbon film or the like, and completely block light that is transmitted from one surface side to the other surface side.

  An optical path of light entering the viewing angle control unit 12 of the viewing angle control sheet 10 having such a configuration will be briefly described with reference to FIG. In FIG. 2, the optical paths of the lights L1, L2, L3 and L4 are schematically shown. Now, the vertical light L1 incident on the vicinity of the central portion of the viewing angle control unit 12 from the image source side passes straight through the inside of the viewing angle control sheet 10 and reaches the observer. Incident light L2 incident on the viewing angle control unit 12 at a predetermined angle from the image source side is inclined on the slope due to a difference in refractive index between the non-light-shielding part 14 having the refractive index Ny and the light-shielding part 15 (transparent part 16) having the refractive index Nx. The light is totally reflected and emitted as vertical light to the viewer side. The light L3 incident on the viewing angle control unit 12 from the image source side with a larger angle is totally reflected on the inclined surface, and has a small angle opposite to the incident direction and an angle close to that of vertical light on the viewer side. Idemitsu. The external light L4 incident on the inclined surface from the observer side with a small angle of a predetermined angle or less enters the light shielding part 15 without being totally reflected even by the refractive index difference between the light shielding part 15 and the non-light shielding part 14. Since a plurality of light absorption layers 21, 22,... Formed in parallel to the light receiving surface are arranged inside the light shielding portion 15, the external light L 4 is caused by the light absorption layers 21, 22,. Absorbed. Therefore, the contrast of the image according to the visual field from the observer side is improved. In this way, the viewing angle can be controlled in the cross-sectional direction, and a reduction in luminance can be suppressed, and the viewing angle control sheet 10 with high contrast can be obtained.

FIG. 3 is an enlarged view of the light shielding portion 15 of the viewing angle control sheet 10. Now, when the width of the opening (wedge-shaped light receiving surface side bottom) of each light shielding portion 15 is W, and the vertical length of the light shielding portion 15 from the image light source side to the viewer side is D, these W And D,
W ≦ D ≦ 15W
It is preferable that this relationship is established. By limiting the relationship between them within such a range, the viewing angle can be set in the range of about 6 ° to about 70 ° on the viewing angle control sheet 10 by setting the above θ to 3 ° or more and 26 ° or less. The characteristic that the contrast with respect to is greatly improved can be given.

FIG. 4 is an enlarged view showing two adjacent light absorption layers in the light shielding portion 15. Here, two adjacent light absorption layers 22 and a light absorption layer 23 will be described as an example. Of the light absorption layers 22 and 23, the width of the light absorption layer 22 on the light receiving surface side is W _i , the width of the light absorption layer 23 on the observer side is W _{i + 1} , and the distance between both the light absorption layers 22 and 23 is d _i . To do. At this time, the light L5 that is substantially parallel to the slope of the light shielding portion 15 and passes through the point A on one end side of the light absorption layer 22 and the point B on one end side far from A of the light absorption layer 23 Consider. One point on the oblique side of the light shielding portion 15 is Z, a line segment passing through the point A and orthogonal to the oblique side is XY, and an end point on the opposite side of the light absorbing layer 22 from the point A is C. Further, D is a point where a line segment orthogonal to the light absorption layers 22 and 23 and passing through the point B intersects with the line segment AC. Assuming that the slope of the hypotenuse is θ (below this, all angles are radians), ∠YAC is also θ.

now,
∠CAB = α
Then, at point A, Snell's law
Nysin (π / 2) = Nxsin (θ + α)
That is,
α = sin ⁻¹ (Ny / Nx) −θ
On the other hand, in △ ABD,
tan α = 2d _i / (W _i + W _{i + 1} )
Therefore,
α = tan ⁻¹ (2d _i / (W _i + W _{i + 1} ))
That is,
tan ⁻¹ (2d _i / (W _i + W _{i + 1} ))> sin ⁻¹ (Ny / Nx) −θ
By defining the lengths of d _i , W _i , and W _{i + 1} with respect to the predetermined Ny, Nx, and θ, the light parallel to the slope of the light shielding unit 15 or light close to it can be obtained. It is possible to prevent the light from passing through the light shielding portion 15 obliquely in the lateral direction.

FIG. 5 is a schematic cross-sectional view illustrating a state in which the light reflected by the inclined surface of the light shielding portion 15 of the viewing angle control sheet 10 reaches the observer side, and there are three cases for comparison (FIG. 5A). (C)) are shown in one figure. In FIG. 5, the video source side is shown on the left side of the drawing and the observer side is shown on the right side of the drawing.
The angle formed by the slope portion of the light shielding portion and the normal line of the light receiving surface is θ, and the ratio between the refractive index Nx of the material constituting the light shielding portion and the refractive index Ny of the non-light shielding portion is Δn (Δn = Nx / Ny). FIG. 5A shows a case where Δn takes a small value, and total reflection is performed within the range of G1 in the figure. FIG. 5B shows a boundary where the totally reflected light reaches the front surface when Δn−cos θ = 0, and the light is totally reflected in the range G2 in the figure. FIG. 5C shows a case where Δn takes a large value, and the reflected light does not go to the front but totally reflects in the range of G3 in the figure. In the present invention, considering practical characteristics,
−0.01 <Δn−cos θ <0.002
Satisfying the following relational expression is a preferable range. When the value of (Δn−cos θ) is −0.01 or less, the total reflected light increases and the totally reflected light is observed at a wide angle. Therefore, particularly when the totally reflected light is observed from an oblique direction, the distance between the ghost image and the actual image becomes large. For this reason, the ghost image becomes very conspicuous and the image quality is lowered. On the other hand, if the value of (Δn−cos θ) is 0.002 or more, the total reflected light is small and the effective image light is difficult to reach the observer, so that the effect of increasing the luminance cannot be obtained sufficiently.
In the present invention, the cross-sectional shape of the light-shielding portion is applicable to any of the above-described triangles and substantially trapezoidal shapes.

  FIG. 6 is a diagram showing an example of a method for creating the viewing angle control sheet of the present invention. FIG. 6 shows an example of a method for creating the viewing angle control sheet of the present invention in the order of (a) to (e). In FIG. 6A, an exposure pattern 62 is arranged on the photosensitive adhesive layer 61, and weakly diffused light 60 is irradiated from the upper part of the paper surface. Of the photosensitive adhesive layer 61 irradiated with the weakly diffused light 60 via the exposure pattern 62, the portion irradiated with light is exposed to become non-adhesive portions 61b, 61b,. On the other hand, portions of the photosensitive adhesive layer 61 that have not been irradiated with the weakly diffused light 60 remain as adhesive portions 61a, 61a,. Since the weakly diffused light 60 diffuses downward in the drawing, as shown in FIG. 6B, the non-adhesive portion 61b has a shape that spreads downward in the drawing, and on the contrary, the adhesive portion 61a The shape gradually becomes narrower in the downward direction on the paper.

  Then, as shown in FIG. 6C, a light shielding sheet 63 is arranged on the lower surface side of the adhesive portions 61a, 61a,... And the non-adhesive portions 61b, 61,. , And the lower surfaces of the non-adhesive portions 61b, 61b,... Then, the pressure-shielding light-shielding sheet 63 is peeled off from the end (FIG. 6D). Then, since the bottom surface of the adhesive portion 61a has adhesiveness, the light shielding sheet 63 remains attached, while the non-adhesive portion 61b loses adhesiveness due to light exposure. Does not remain on the side The refractive index of the non-adhesive portion 61b is slightly larger than the refractive index of the adhesive portion 61a due to photosensitivity. The adhesion part 61a becomes the transparent part 16 of the light shielding part 15 of the viewing angle control sheet of the present invention. The light shielding sheets 63a, 63a,... Adhered to the lower surface of the adhesive portion 61a are any of the light absorption layers 21, 22, 23,... Of the light shielding portions 15 of the viewing angle control sheet of the present invention. Thus, the first layer 65 of the viewing angle control sheet in which the light shielding portions 15 and the non-light shielding portions 14 are alternately arranged in the surface direction is created (FIG. 6E).

  FIG. 7 is a diagram showing the next step of the creation method of FIG. Here, as shown in FIG. 7F, the photosensitive adhesive layer 71 is disposed again on the lower surface side of the first layer 65 described above. The exposure pattern 62 on the first layer 65 is similarly arranged, and the weakly diffused light 60 is irradiated again from the upper part of the paper surface. Of the photosensitive adhesive layer 71 irradiated with the weakly diffused light 60 via the exposure pattern 62, the portion irradiated with light is exposed to become non-adhesive portions 71b, 71b,. On the other hand, portions of the photosensitive adhesive layer 71 that have not been irradiated with the weakly diffused light 60 remain as adhesive portions 71a, 71a,. Since the weakly diffused light 60 is diffused downward in the drawing, as shown in FIG. 7G, the non-adhesive portion 71b is similar to the non-adhesive portion 61b and further on the extension below the drawing. The shape spreads in the direction. On the contrary, the adhesive portion 71a gradually becomes narrower in the downward direction on the paper surface on the extension of the adhesive portion 61a.

  Then, as shown in FIG. 7 (h), a light shielding sheet 73 is arranged on the lower surface side of the adhesive portions 71a, 71a,... And the non-adhesive portions 71b, 71b,. , And the lower surfaces of the non-adhesive portions 71b, 71b,... Then, the pressure-shielding light-shielding sheet 73 is peeled from the end (FIG. 7 (i)). Then, since the bottom surface of the adhesive portion 71a has adhesiveness, the light-shielding sheet 73 is stuck and remains, while the non-adhesive portion 71b loses adhesiveness due to light exposure. Does not remain on the side The refractive index of the non-adhesive part 71b is slightly larger than the refractive index of the adhesive part 71a due to photosensitivity. The adhesion part 71a becomes the transparent part 16 of the light shielding part 15 of the viewing angle control sheet of the present invention. The light shielding sheets 73a, 73a,... Adhered to the lower surface of the adhesive portion 71a are any of the light absorbing layers 21, 22, 23,... Of the light shielding portions 15 of the viewing angle control sheet of the present invention. Thus, the second layer 75 of the viewing angle control sheet in which the light shielding portions 15 and the non-light shielding portions 14 are alternately arranged in the surface direction is formed adjacent to the first layer 65 on the lower surface side (FIG. 7). (J)). Thereafter, the same operation is repeated to obtain the viewing angle control sheet of the present invention having a plurality of structures in which a non-light-shielding portion and a light-shielding portion are alternately provided in the layer and a light-absorbing layer is arranged on one side of the light-shielding portion. .

  FIG. 8 is a diagram showing another example of a method for creating a viewing angle control sheet of the present invention. In this method, a photosensitive adhesive layer 82 is disposed on the bottom surface on the flat side of the lenticular lens 81 (FIG. 8A), and parallel light 80 is irradiated from the spherical surface side of the lenticular lens 81 (FIG. 8B). The parallel light 80 is directed to the focal point by the lenticular lens 81, and the photosensitive adhesive layer 82 disposed on the optical path is exposed to a predetermined pattern. In this case, the inclinations of the light-sensitive portions 82a, 82a,... And the non-photosensitive portions 82b, 82b,... With respect to the direction of the light 80 are opposite to those described in FIGS. That is, as shown in FIG. 8C, the photosensitive portion 82a has a narrow shape on the side in the direction of irradiation light. Of the photosensitive adhesive layer 82 irradiated with the parallel light 80 via the lenticular lens 81, the portion irradiated with the light is exposed to become non-adhesive portions 82a, 82a,. On the other hand, portions of the photosensitive adhesive layer 82 that have not been irradiated with the parallel light 80 remain as adhesive portions 82b, 82b,.

  Next, the light shielding sheet 83 is pressure-bonded / peeled to the lower surface side of the photosensitive adhesive resin layer 82 and is adhered only to the lower surface side of the non-photosensitive portions 82b, 82b,. The refractive index of the non-adhesive portion 82a is slightly larger than the refractive index of the adhesive portion 82b when exposed. The adhesive part 82b becomes the transparent part 16 of the light shielding part 15 of the viewing angle control sheet of the present invention. The light shielding sheets 83a, 83a,... Adhered to the lower surface of the adhesive portion 82b are any of the light absorption layers 21, 22, 23,... Of the light shielding portions 15 of the viewing angle control sheet of the present invention. Thus, the first layer 85 of the viewing angle control sheet in which the light shielding portions 15 and the non-light shielding portions 14 are alternately arranged in the surface direction is created (FIG. 8E). Thereafter, in the same manner as described with reference to FIG. 7, the second and subsequent layers are sequentially formed to obtain the target viewing angle control sheet.

  The resin composition constituting the photosensitive adhesive layer includes at least (A) a heat-adhesive binder comprising an organic polymer, and (B) a compound having at least one ethylenic double bond having radical polymerizability. And (C) a biimidazole photopolymerization initiator and (D) an oxirane ring-containing compound. Furthermore, it is more preferable that the component (C) includes a (c1) hexaarylbiimidazole compound represented by the general formula (1) and a (c2) hydrogen donating compound as components of the biimidazole photopolymerization initiator.

（式中、Ｌ_１、Ｌ_２及びＬ_３はそれぞれ独立にアリール基或いは、置換アリール基を表す。）

(In the formula, L ₁ , L ₂ and L ₃ each independently represents an aryl group or a substituted aryl group.)

  FIG. 9 is a diagram showing an example of the configuration of the viewing angle control sheet of the present invention. The viewing angle control sheet 90 shown in FIG. 9 includes a viewing angle control unit 92 whose horizontal cross-sectional shape is constant in the vertical direction. A base sheet 91 is disposed on the image source side, and a base sheet 93 is disposed on the observer side. In the drawing, these three are shown apart for the sake of understanding, but they are actually bonded together.

  FIG. 10 shows a configuration of the display device 100 including the viewing angle control sheet according to the present invention. In FIG. 10, the lower left direction on the front side of the paper is the image source side, and the upper right direction on the back side of the paper is the viewer side. The display device 100 of the present invention includes a liquid crystal display panel 101, a viewing angle control sheet 102 in which viewing angle control units are arranged in a vertical direction, and a viewing field in which viewing angle control units are arranged in a horizontal direction in order from the video source side. A corner control sheet 103 is laminated, and a functional sheet 104 having at least one function of AR, AS, AG, and touch sensor is provided on the observer side. The base sheets of the viewing angle control sheet 102 and the viewing angle control sheet 103 are omitted in the drawing. The arrangement of the viewing angle control sheet 102 and the viewing angle control sheet 103 may be interchanged. In FIG. 10, these are shown separated from each other, but this is for the sake of understanding the drawing, and in fact they are in contact with each other or bonded together.

(Example) The area ratio of the light absorption layer on the light receiving surface side was set to 50%, and the distance between the light absorption layers was set to 0.005 mm to provide five layers. The area ratio of the light absorption layer in each layer cross section was 50%, 40%, 30%, 20%, and 10%, including the uppermost layer. The half-value viewing angle was set to 30 °, and the pitch between the light absorption layer on the light receiving surface side and the non-light-shielding portion was set to 0.05 mm.
The refractive index Ny of the non-light-shielding part was 1.56, and the refractive index Nx of the light-shielding part (transparent part) was 1.55.

  (Comparative Example) A 50% transmittance tint sheet was placed in front of the display.

(Evaluation methods)
1. Luminance Using a luminance meter, the front luminance in black and white display when each of the above sheets was set was measured and compared.
2. Contrast The front brightness when the power was turned off (black display) in a bright room was measured, and the contrast was compared with the measured black brightness ratio. The illuminance in the bright room was measured at 1000 lux.
(Evaluation results) The example showed values of 1.5 times the luminance and twice the contrast of the comparative example.

  While the present invention has been described in connection with embodiments that are presently the most practical and preferred, the present invention is not limited to the embodiments disclosed herein. However, the present invention can be changed as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification, and a viewing angle control sheet accompanying such a change is also included in the technical scope of the present invention. It must be understood as a thing.

It is a figure which shows the cross section by the plane orthogonal to the light-receiving surface of the viewing angle control sheet | seat of this invention. It is a figure which shows permeation | transmission and interruption | blocking of the light by the viewing angle control sheet | seat of this invention. It is a figure which expands and shows the light-shielding part of a viewing angle control sheet. It is a figure which expands and shows two adjacent light absorption layers in a light-shielding part. It is a cross-sectional schematic diagram which illustrates the state in which the light reflected on the slope of the light-shielding part of a viewing angle control sheet | seat reaches | attains an observer side. It is a figure which shows an example of the method of producing the viewing angle control sheet | seat of this invention. It is a figure which shows the next process of the preparation method of FIG. It is a figure which shows another example of the method of producing the viewing angle control sheet | seat of this invention. It is a figure which shows another example of a structure of a viewing angle control sheet. It is a figure which shows an example of a structure of the display apparatus provided with the viewing angle control sheet | seat of this invention. It is a figure which shows an example of the conventional viewing angle control sheet.

Explanation of symbols

L1, L2, L3, L4, L5 Light 10 Viewing angle control sheet 11 Image source side base sheet 12 Viewing angle control part 13 Observer side base sheet 14 Non-shielding part 15 Shielding part 16 Transparent parts 21, 22,. 61, 71 Photosensitive adhesive layer 81 Lenticular lens 100 Display device

Claims (12)

A viewing angle control unit including a light shielding part and a non-light shielding part;
The light shielding part is formed in the observer direction from the light receiving surface of the viewing angle control unit, and a plurality of the light shielding parts are arranged apart from each other in the light receiving surface direction,
A light-absorbing layer is formed on each light-shielding portion at a substantially equal distance from the light-receiving surface in the observer direction, and a plurality of the light-absorbing layers are provided in each light-shielding portion. . When the total area of the light absorption layer closest to the light receiving surface is R and the area of the entire light receiving surface is S,
0.1 <R / S <0.4
The viewing angle control sheet according to claim 1, wherein the following relationship is established. 3. The viewing angle control sheet according to claim 1, wherein the light shielding portion has a wedge shape that gradually becomes narrower from the light receiving surface toward the viewer. 4. The light shielding portion includes the light absorbing layer and a transparent portion disposed between the light absorbing layers, and the refractive index of the material constituting the transparent portion is Nx, and the refractive index of the material constituting the non-light shielding portion is Ny. and when,
Nx ≦ Ny
The viewing angle control sheet according to claim 3, wherein the following relationship is established. When the angle between the wedge-shaped slope portion and the normal line of the light exit surface is θ, Nx / Ny = Δn,
−0.01 <Δn−cos θ <0.002
The viewing angle control sheet according to claim 3 or 4, wherein the following relationship is established. In each light shielding part, when the width of the light absorption layer closest to the light receiving surface is W, and the length from the light absorption layer closest to the light receiving surface to the part closest to the observer of the light shielding part is D,
W ≦ D ≦ 15W
The viewing angle control sheet according to claim 3, wherein the following relationship is established. In each light shielding portion, among the light absorbing layers adjacent to each other, the width of the light absorbing layer on the light receiving surface side is W _i , the width of the light absorbing layer on the viewer side is W _{i + 1} , and the distance between the two light absorbing layers is d _i
And when
tan ⁻¹ (2d _i / (W _i + W _{i + 1} ))> sin ⁻¹ (Ny / Nx) −θ
The viewing angle control sheet according to claim 3, wherein the following relationship is established. The viewing angle control sheet according to any one of claims 3 to 7, wherein the light shielding part is formed by repeating patterning of the photosensitive adhesive layer and transfer of the light absorption layer. The viewing angle control sheet according to claim 8, wherein a lenticular lens is used for the patterning. 10. A viewing angle control sheet according to claim 1, wherein one viewing angle control sheet according to claim 1 is laminated on the viewer side of the image source, or two substantially perpendicularly stacked. 11. The device according to claim 1, wherein at least one of AR, AS, AG, and a touch sensor, or a plurality of additional functions among them, is provided on at least one surface side. Viewing angle control sheet. A display device comprising the viewing angle control sheet according to claim 1 bonded thereto.

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