KR20110004311A - Light control plate, surface light source device and transmissive image display device - Google Patents

Abstract

PURPOSE: A light controlling plate, surface-light-source, and a transmissive type image display device are provided to stably display images by adopting a convex part satisfying a specific formula to the light controlling plate. CONSTITUTION: A light controlling plate(40) includes a first face(40a) and a second face(40b). The first face is formed at light source side. The second face is formed at transmissive type image display part side. A plurality of convex parts(41) is formed at the second face. The convex parts satisfy formula below: Z_B(X) - 0.01W_a <= Z(X) <= Z_B(X) + 0.01W_a. In the formula, Z_B(X) is Z_0(X) x r, the r is between 0.95 and 1.05.

Description

Light control panel, surface light source device, and transmissive image display device {LIGHT CONTROL PLATE, SURFACE LIGHT SOURCE DEVICE AND TRANSMISSIVE IMAGE DISPLAY DEVICE}

The present invention relates to a light control panel, a surface light source device and a transmissive image display device.

In transmission type image display apparatuses, such as a liquid crystal display device, the direct type surface light source device is used as an example of the light source which outputs the backlight of a liquid crystal display part. As a typical surface light source device, what arrange | positioned several light source on the back side of the light control board called a light-diffusion plate is used. In such a surface light source device, the light emitting surface can be easily made high by increasing the number of light sources to be arranged, but there is a problem that the luminance uniformity is low. In particular, the periodic luminance non-uniformity caused by the increase in luminance immediately above the light source is a problem, and the periodic luminance non-uniformity has become a bigger problem due to the reduction in the number of light sources for reducing the surface light source device or lowering power consumption. have.

Therefore, in order to secure the luminance uniformity, for example, Japanese Patent Application Laid-Open No. 6-273760 (Patent Document 1) forms a light amount correction pattern on the light diffusion plate as an example of the light control plate corresponding to the distance to the light source. Similarly, in Japanese Patent Application Laid-Open No. 2004-127680 (Patent Document 2), light is provided in the vicinity of a light source with a large amount of light by providing a cross-sectional serrated prism in a part of a portion immediately above the light source on the light source side of the light diffusion plate. Is dispersed.

However, in a backlight configuration in which the light amount correction pattern of Patent Document 1 and the cross-sectional saw-tooth prism of Patent Document 2 have a dependence on the distance from the light source position, the optical control plate called the light diffusion plate is deformed due to positional shift or deformation by heat. The luminance equalization will deteriorate.

Accordingly, an object of the present invention is to provide a light control plate capable of more stably suppressing luminance unevenness, and a surface light source device and a transmissive image display device including the light control plate.

The light control panel according to the present invention is a light control plate capable of emitting light incident from the first surface from a second surface located on the side opposite to the first surface, and extends in the first direction and is orthogonal to the first direction. A plurality of convex portions arranged in parallel in the direction are formed on the second surface, and in the cross section orthogonal to the first direction of the convex portion, the axis passing through both ends with respect to the second direction of the convex portion is assumed as the x axis, When the axis line orthogonal to the x-axis is passed on the x-axis and is orthogonal to the x-axis, and the length in the x-axis direction of the convex portion is w _a , the contour shape of the convex portion in the cross section is -0.475w _a ≤ It is represented by z (x) that satisfies Equation 1 in the range of x≤0.475w _a .

However, in Equation 1, z _B (x) = z ₀ (x) x r (r is 0.95 or more and 1.05 or less), and z ₀ (x) is represented by Equation (2).

(Mathematical formula 2, h _a is a constant less than 0.27w _a more than 1.02w _a, k is _a constant of 0.00 or less than -0.38)

In this configuration, since the convex portion has a cross-sectional shape represented by z (x), the luminance nonuniformity of the light emitted from the light control panel can be more stably reduced.

The surface light source device which concerns on this invention is equipped with the light control board which concerns on this invention, and the some light source which is arrange | positioned apart from each other, and supplies light to the 1st surface of a light control board.

Since this surface light source device is equipped with the light control board which concerns on this invention, the luminance nonuniformity of the light radiate | emitted from a light control board can be reduced more stably.

The transmissive image display device according to the present invention includes a light control plate according to the present invention, a plurality of light sources arranged apart from each other and supplying light to a first surface of the light control panel, and output from a plurality of light sources and pass through the light control panel. A transmissive image display unit which is illuminated by a light and displays an image is provided.

In this transmissive image display apparatus, since the light control panel which concerns on this invention is provided, the transmissive image display part can be illuminated stably with the light in which the luminance nonuniformity was suppressed. Therefore, it is possible to stably display an image without luminance unevenness.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the structure of one Embodiment of the transmissive image display apparatus which concerns on this invention.
FIG. 2 is an enlarged view of a light diffusion plate used in the transmissive image display device shown in FIG. 1.
It is a figure which shows an example of the cross-sectional shape orthogonal to the extension direction of a convex-shaped part.
It is a figure which shows the permissible fluctuation range of the outline which shows the cross-sectional shape of the convex part shown in FIG.
5 is a diagram illustrating a desired intensity distribution of output light from the convex portion.
It is a figure which shows an example of the intensity distribution measuring method.
7 is a diagram illustrating a simulation model for designing convex portions.
8 is a diagram illustrating one step of the design of the convex portion.
9 is a diagram illustrating an example of an intensity distribution between two adjacent light sources.
10 is a diagram illustrating another example of the intensity distribution between two adjacent light sources.
11 is a diagram illustrating still another example of the intensity distribution between two adjacent light sources.
It is a figure which shows an example of the cross-sectional shape orthogonal to the extending direction of a convex-shaped part.
It is a figure which shows the condition which the contour line which shows the cross-sectional shape of the convex part shown in FIG. 12 is satisfied.
14 is a view showing a z ₀ (x) of the convex-shaped portion Example 1 shown in Fig.
15 is a diagram illustrating a condition that the contour of Form 1 is satisfied.
16 is a view showing a z ₀ (x) of the convex portion 2 for example, the shape shown in Fig.
17 is a diagram illustrating a condition that the contour of Form 2 is satisfied.
It is a figure which shows another example of the cross-sectional shape orthogonal to the extending direction of a convex-shaped part.
It is a figure which shows the conditions which satisfy | fill the outline which shows the cross-sectional shape of the convex-shaped part shown in FIG.
20 is a view showing a z ₀ (x) of the convex portion shape shown in Example 3, 18.
21 is a diagram illustrating a condition that the contour of Form 3 is satisfied.
22 is a view showing a z ₀ (x) of the convex portion shape shown in Example 4. Fig.
It is a figure which shows the conditions which the contour of the shape example 4 satisfy | fills.
It is a figure which shows another example of the cross-sectional shape orthogonal to the extension direction of a convex-shaped part.
It is a figure which shows the conditions which the outline of the convex-shaped part shown in FIG. 24 satisfy | fills.
It is a figure which shows still another example of the cross-sectional shape orthogonal to the extension direction of a convex-shaped part.
It is a figure which shows the condition which the outline of the convex-shaped part shown in FIG. 26 satisfy | fills.
It is a figure which shows still another example of the cross-sectional shape orthogonal to the extending direction of a convex-shaped part.
It is a figure which shows the condition which the outline of the convex-shaped part shown in FIG. 28 satisfy | fills.
It is a figure which shows still another example of the cross-sectional shape orthogonal to the extending direction of a convex-shaped part.
It is a figure which shows the conditions which the outline of the convex-shaped part shown in FIG. 30 satisfy | fills.
It is a figure which shows still another example of the cross-sectional shape orthogonal to the extension direction of a convex-shaped part.
33 is a diagram illustrating a condition that the contour of the convex portion shown in FIG. 32 is satisfied.
It is a figure which shows still another example of the cross-sectional shape orthogonal to the extension direction of a convex-shaped part.
FIG. 35 is a diagram illustrating a condition that the contour of the convex portion shown in FIG. 34 satisfies. FIG.
It is a figure which shows still another example of the cross-sectional shape orthogonal to the extension direction of a convex-shaped part.
FIG. 37 is a diagram illustrating a condition that the outline of the convex portion shown in FIG. 36 is satisfied. FIG.
38 is a view showing still another example of the cross-sectional shape orthogonal to the extending direction of the convex portion.
FIG. 39 is a diagram illustrating a condition that the outline of the convex portion shown in FIG. 38 is satisfied.
It is a schematic diagram which shows the simulation model of an Example and a comparative example.
41 is a diagram showing design data at the design stage of the convex portion used in the simulation of Example 1. FIG.
42 is a diagram showing design data at the design stage of the convex portion used in the simulation of Example 2. FIG.
43 is a diagram showing design data at the design stage of the convex portion used in the simulation of Example 3. FIG.
44 is a diagram showing design data at the design stage of the convex portion used in the simulation of Example 4. FIG.
45 is a diagram showing design data at the design stage of the convex portion used in the simulation of Example 5. FIG.
46 is a diagram showing design data at the design stage of the convex portion used in the simulation of Example 6. FIG.
47 is a diagram showing design data at the design stage of the convex portion used in the simulation of Example 7. FIG.
48 is a chart which shows design data at the design stage of the convex portion used in the simulation of Example 8. FIG.
FIG. 49 is a chart showing design data at the design stage of the convex portion used in the simulation of Example 9. FIG.
50 is a chart showing design data at the design stage of the convex portion used in the simulation of Example 10;
Fig. 51 is a table showing design data in the design stage of the convex portion used in the simulation of the eleventh embodiment.
52 is a chart which shows design data at the design stage of the convex portion used in the simulation of Example 12. FIG.
53 is a chart showing the simulation results of Examples 1 to 12 and Comparative Example 1. FIG.
54 is a diagram showing design data at the design stage of the convex portion used in the simulation of Example 13. FIG.
FIG. 55 is a diagram showing a cross-sectional shape of the convex portions of Examples 14 to 17 and Comparative Example 2. FIG.
FIG. 56 shows the results of simulation 1 in Comparative Example 2. FIG.
57 is a diagram showing the results of simulation 2 in Comparative Example 2. FIG.
It is a figure which shows intensity distribution based on the result of the simulation 3 in the comparative example 2. FIG.
FIG. 59 is a diagram showing the results of simulation 1 in Example 14. FIG.
60 is a diagram illustrating the results of simulation 2 in Example 14. FIG.
Fig. 61 is a diagram showing the intensity distribution based on the result of simulation 3 in Example 14;
62 shows the results of simulation 1 in Example 15. FIG.
FIG. 63 is a diagram showing the results of simulation 2 in Example 15. FIG.
64 is a diagram showing the intensity distribution based on the result of simulation 3 in Example 15. FIG.
65 shows the results of simulation 1 in Example 16. FIG.
66 is a diagram showing the results of simulation 2 in Example 16. FIG.
67 is a diagram showing the intensity distribution based on the result of simulation 3 in Example 16. FIG.
FIG. 68 is a diagram showing the results of simulation 1 in Example 17. FIG.
69 is a diagram showing the results of simulation 2 in Example 17. FIG.
70 is a diagram showing the intensity distribution based on the result of simulation 3 in Example 17. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, with reference to drawings, embodiment of the light control board, surface light source device, and transmissive image display apparatus of this invention is described. In addition, in description of drawing, the same code | symbol is attached | subjected to the same element, and the overlapping description is abbreviate | omitted. In addition, the dimension ratio of drawing does not necessarily correspond with what was described.

(1st embodiment)

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the structure of one Embodiment of the transmissive image display apparatus which concerns on this invention. 1 is an exploded view of a transmissive image display device. FIG. 2 is an enlarged view of a light diffusion plate (light control panel) included in the surface light source device included in the transmissive image display device shown in FIG. 1, and shows a cross-sectional structure of the light diffusion plate. In FIG. 2, two adjacent light sources are also shown typically for convenience of description.

As the transmissive image display part 10, the liquid crystal display panel in which the linear polarizing plates 12 and 13 were arrange | positioned on both surfaces of the liquid crystal cell 11 is mentioned, for example. In this case, the transmissive image display apparatus 1 is a liquid crystal display device (or liquid crystal television). The liquid crystal cell 11 and the polarizing plates 12 and 13 can use what is used by transmission type image display apparatuses, such as a conventional liquid crystal display device. As the liquid crystal cell 11, well-known liquid crystal cells, such as TFT type and STN type, are illustrated.

The surface light source device 20 is a so-called direct surface light source device 20, and has a light source unit 30 including a plurality of light sources 31 arranged in parallel. Each light source 31 is a linear light source extending in the direction orthogonal to the arrangement direction of the some light source 31, and the thing of the straight pipe shape like a fluorescent lamp (cold cathode lamp) is illustrated. The plurality of light sources 31 are arranged at intervals so that the center axes of the respective light sources 31 are located in the same plane P1, and the distance between the center axes of two adjacent light sources 31 and 31 is L. FIG. In one case, the distance L is 10 mm to 150 mm, for example. Although the light source 31 was made linear, here, it is also possible to use a point light source like LED. In addition, the plane P1 shown in FIG. 1 is for convenience of description, and is a virtual plane.

As shown in FIG. 1, it is preferable that some light source 31 is arrange | positioned in the lamp box 32, and it is preferable that the inner surface 32a of the lamp box 32 is formed as a light reflection surface. This is because the light output from each light source 31 is reliably output to the transmissive image display unit 10 side, so that the light from each light source 31 can be efficiently used. In this embodiment, the light source unit 30 will be described as having the lamp box 32 having the above-described preferred configuration.

The surface light source device 20 is a light diffusing plate serving as a light control plate disposed on the front side (upper side in FIG. 1) of the light source unit 30, that is, on the transmissive image display unit 10 side with respect to the light source 31. Have 40. As described later, when the separation distance between the light diffusion plate 40 and the light sources 31 is D, the separation distance D is, for example, 3 mm to 50 mm. In the surface light source device 20, in order to reduce the thickness, two adjacent light sources are provided such that L / D is 1.5 or more, preferably L / D is 2 or more, and more preferably L / D is 2.5 or more. The distance L and the separation distance D between (31, 31) are selected.

The light diffusion plate 40 does not project the image of each light source 31 onto the transmissive image display unit 10, so that light from the light source unit 30, that is, direct light from each light source 31 and lamp box 32 is used. Diffused irradiation of the reflected light reflected from the inner surface 32a of the side toward the transmissive image display unit 10. The thickness d ₁ of the light diffusion plate 40 is usually 0.1 mm or more and 5 mm or less, preferably 0.5 mm or more and 3 mm or less, more preferably 0.8 mm or more and 2 mm or less.

The light diffusion plate 40 is made of a transparent material. The refractive index of a transparent material is usually 1.48 or more and 1.62 or less, or 1.56 or more and 1.62 or less, and transparent resin and transparent glass can be illustrated as a transparent material. Examples of the transparent resin include polycarbonate resin (refractive index: 1.59), MS resin (methyl methacrylate-styrene copolymer resin) (refractive index: 1.56 to 1.59), polystyrene resin (refractive index: 1.59), and the like.

When using a transparent resin material as a transparent material, additives, such as a ultraviolet absorber, an antistatic agent, antioxidant, a processing stabilizer, a flame retardant, a lubricating agent, can also be added to this transparent resin material. These additives can be used individually or in combination of 2 types or more, respectively.

Examples of the ultraviolet absorbents include benzotriazole ultraviolet absorbers, benzophenone ultraviolet absorbers, cyanoacrylate ultraviolet absorbers, malonic ester ultraviolet absorbers, oxalic acid anhydride ultraviolet absorbers, triazine ultraviolet absorbers, and the like. Preferably, they are a benzotriazole type ultraviolet absorber and a triazine type ultraviolet absorber.

Although a transparent resin material is normally used without adding a light diffusing agent as an additive, as long as it is a small quantity which does not impair the objective of this invention, you may add and use a light diffusing agent.

As the light diffusing agent, a powder having a refractive index different from that of the transparent material mainly constituting the light diffusing plate 40 is usually used, which is dispersed and used in the transparent material. As such a light diffusing agent, organic particles, such as styrene resin particles and methacryl resin particles, inorganic particles, such as potassium carbonate particles and silica particles, are used, and the particle diameter is 0.8 micrometer-50 micrometers normally.

Moreover, in order to reduce moire, the surface on the light source 31 side can also be made into the surface which has light diffusivity. For example, the surface on the light source 31 side may be constituted by a skin layer containing fine particles called a matting agent, and the surface on the light source 31 side may be embossed or blasted, and the matting agent and the binder may be used. You may apply the coating liquid containing these and form a mat layer.

The light diffusion plate 40 may be a single layer plate made of a single transparent material, or may be a multilayer plate having a structure in which layers made of different transparent materials are stacked. When the light diffusing plate 40 is a multilayer plate, one or both surfaces of the light diffusing plate 40 have a structure in which a skin layer having a thickness of usually 10 μm to 200 μm, preferably 20 μm to 100 μm is formed. It is preferable to use what added the ultraviolet absorber as a transparent material which comprises a skin layer. By setting it as such a structure, deterioration of the light-diffusion plate 40 by the ultraviolet-ray which may be included in the light source 31 or the light from the outside can be prevented. In particular, in the case where a fluorescent tube or the like is used as the light source 31, since a deterioration due to ultraviolet rays from the fluorescent tube can be prevented, it is preferable that a skin layer is formed on the surface of the light source 31 side. It is more preferable in terms of cost that a skin layer is not formed on the surface of the transmissive image display unit 10 (for example, a liquid crystal panel). When using what added the ultraviolet absorber as a transparent resin material which comprises a skin layer, the content is 0.5 mass%-5 mass% normally based on a transparent resin material, Preferably they are 1 mass%-2.5 mass%.

The light diffusion plate 40 may be coated with an antistatic agent on one or both surfaces. By applying the antistatic agent, it is possible to prevent the adhesion of dust due to static electricity and the like, and to lower the light transmittance due to the adhesion of dust.

As shown in FIG. 1 and FIG. 2, the light diffusion plate 40 has a substantially flat first surface 40a on the light source unit 30 side and a second surface 40b on the transmissive image display unit 10 side. Has A plurality of convex portions (optical element portions) 41 are formed on the second surface 40b. In the light diffusion plate 40 in which such convex portions 41 are formed, the thickness d ₁ can be the distance between the top of the convex portion 41 and the first surface 40a.

As shown in FIG. 2, each convex part 41 is a linear optical element extended in one direction (1st direction). Examples of the optical element include a lens and a prism. The plurality of convex portions 41 are arranged in parallel in a direction substantially perpendicular to the extension direction. The plurality of convex portions 41 are closely formed over both side surfaces 40c and 40d (see FIG. 1) of the light diffusion plate 40, that is, the ends 41a of the adjacent convex portions 41. , 41a is ideally located at the same position in the width direction of the convex portion 41, but the width w _a of the convex portion 41 between the plurality of convex portions 41 is for ease of fabrication. An approximately flat portion of about 5% or less may be provided.

The cross-sectional shape orthogonal to the extending direction of each convex part 41 is substantially the same between the some convex part 41. As shown in FIG. On the other hand, L / D, which is the ratio of the separation distance D and the distance L between two adjacent light sources 31 and 31, is 1.5 or more, preferably L / D is 2 or more, and more preferably L / D. The distance D and the distance L are selected to satisfy the condition that D is 2.5 or more, as described above.

3 is a view showing an example of a cross-sectional shape orthogonal to the extending direction of the convex portion, and shows one enlarged convex portion. The cross-sectional shape of the convex part 41 is demonstrated using the local xz coordinate system set as shown in FIG. The x axis constituting the xz coordinate system is an axis parallel to the array direction (second direction) of the plurality of convex portions 41, and the z axis is an axis line parallel to the plate thickness direction (direction perpendicular to the first and second directions). to be.

The outline of the convex portion 41 in the xz plane of the xz coordinate system is represented by z (x) that satisfies the expression (3) when the length of the convex portion 41 in the x-axis direction is w _a .

In Formula (3), z _B (x) = z ₀ (x) x r (r is 0.95 or more and 1.05 or less). z ₀ (x) is represented by equation (4).

Of Equation 4, h _a is a constant less than 0.27w _a more than 1.02w _a, k is _a constant of 0.00 or less than -0.38. h _a corresponds to the maximum height in the z-axis direction between both ends 41a and 41a of the convex portion 41 in the case where the convex portion 41 is shaped as z ₀ (x). . K _a is a parameter indicating the pointed side of the convex portion 41.

In FIG. 3, z ₀ (x) (h _a = 0.4825w _a , k _a = -0.232 in Equation 4) is predetermined times in the z direction (for example, 1 time) within a range that satisfies the expression (3). The case where the shape is stretched and contracted as much as that is, z (x) = z _B (x) is illustrated. In this case, both ends 41a and 41a are located on the x-axis, and the top part 41b is located on the z-axis. The convex portion 41 also has an outline symmetrical with respect to the z axis.

Considering the influence on the manufacturing error and the intensity distribution in the vicinity of both ends of the convex portion 41, the cross-sectional shape of the convex portion 41 is -0.5w _a × 0.95≤x≤0.5w _a × 0.95 good when expressed as z (x) satisfying the equation (3), preferably, when expressed as z (x) satisfying the equation (3) in _a -0.5w ≤x≤0.5w _a.

The outline shape of the convex part 41 shown by Formula (3) is demonstrated concretely. Z for any position x _a (x _a) corresponds to the height of the convex portion 41 in the position x _a. Accordingly, z (x) represents the contour shape of the convex portion 41. In Equation 3, 0.01w _a corresponds to the allowable variation width of the contour line in the height direction at the position x _a . Thus, when the _B z (x) based on the contour as a reference, as shown in outline, Figure 4 of the convex portion 41, a contour represented by _B z (x) and _a -0.01w z _B What is necessary is just an outline within the permissible fluctuation range between the outlines represented by (x) + 0.01w _a . Therefore, the outline of the convex portion 41 represented by the equation (3) is within a variation allowable width of 0.01 w _a with respect to the reference outline represented by z _B (x). In addition, although the case where r = 1 is shown in FIG. 4, r should just be 0.95 or more and 1.05 or less.

As the width (w _a) of the convex portion _{(41), w a = 410㎛} , there can be mentioned a _{w a = 400㎛, w a =} 353㎛ or w _a = 325㎛. w is the value of _a does not limited to these, and w _a is not more than 800㎛ preferable, and a range from 10㎛ 800㎛ preferable, and further more preferably not more than more than 600㎛ 20㎛.

In addition, although h _a and k _a may be a value within the range mentioned above, h _a and k _a may be the range shown in Table 1 according to the refractive index of the light-diffusion plate 40, especially the refractive index of the convex part 41, for example. desirable.

It is more preferable that it is the range shown in Table 2-Table 8 according to L / D in each refractive index range of the said Table 1.

The light diffusion plate 40 can be produced by, for example, a method of cutting out from a transparent material. In addition, when using a transparent resin material as a transparent material, it can manufacture by methods, such as the injection molding method, the extrusion molding method, the press molding method, the photopolymer method, etc., for example.

In the surface light source device 20 and the transmissive image display device 1 including the light diffusion plate 40, the light output from each light source 31 of the light source unit 30 is directly or the inner surface of the lamp box 32 ( Reflected at 32a) is incident on the light diffusion plate 40. Light incident on the light diffusing plate 40 is irradiated toward the transmissive image display unit 10 from the second surface 40b. At this time, since a plurality of convex portions 41 are formed on the second surface 40b of the light diffusion plate 40, light is emitted through the convex portions 41. Since the convex portion 41 has a cross-sectional shape represented by z (x), the light is refracted in various directions depending on the passing position (emission position) of the light. By this diffusing action, the light from the light source 31 is diffused to produce planar light and the luminance unevenness is suppressed. Therefore, the image of the light source 31 is not projected on the transmissive image display part 10. And since the cross-sectional shape of the convex part 41 is represented by z (x) which satisfy | fills Formula (3), it is also possible to implement | achieve the brightness uniformity of a higher front direction (normal direction of the 1st surface 40a). Do.

In addition, since the cross-sectional shape of the convex portion 41 is represented by z (x) that satisfies the equation (3), for example, L due to deformation due to position shift or heat with respect to the light source 31 of the light diffusion plate 40, etc. Even if / D fluctuates from a predetermined value (for example, a design value), luminance unevenness hardly occurs, and the luminance unevenness can be suppressed more stably.

Therefore, in the surface light source device 20 provided with the light diffusing plate 40, it is possible to more stably output light in which luminance unevenness is suppressed. And in the transmissive image display apparatus 1 containing the light-diffusion plate 40, since the light in which the luminance nonuniformity was suppressed can illuminate the transmissive image display part 10, a light-diffusion plate is aimed at improving display quality. It is possible to suppress fluctuations in display quality due to deformation due to positional shift or heat to the light source 31 of 40.

(2nd embodiment)

In the first embodiment, the convex portion 41 has been described as having a contour line z (x) satisfying the expression (3). However, when the convex part 41 measured the light output from the light source 31 with the detector arrange | positioned on the 2nd surface 40b in which the some convex part 41 was formed, it shows in FIG. It is also possible to realize the intensity distribution 50 as described above. The form in the case where the convex part 41 has a cross-sectional shape which implements the intensity distribution 50 as shown in FIG. 5 is demonstrated. Since the convex part 41 has the characteristic shown in FIG. 3, and is the same as that of 1st Embodiment, it demonstrates by attaching | subjecting the same code | symbol to the same element as 1st Embodiment, and the overlapping description is abbreviate | omitted. do.

As mentioned above, when the convex part 41 measured the light output from the light source 31 with the detector arrange | positioned on the 2nd surface 40b in which the some convex part 41 was formed, FIG. It has a cross-sectional shape which implements the intensity distribution 50 as shown in 5, and the cross-sectional shape of several convex part 41 is the same shape. 5 is a diagram illustrating a desired intensity distribution of the emitted light from the convex portion.

A condition that the intensity distribution 50 satisfies is described with reference to FIG. 5. The direction parallel to a 2nd direction is made into the X-axis direction, and the position of the light source 31 in an X-axis direction is made into the origin (reference point) (O). In FIG. 5, the horizontal axis represents the position with respect to the light source in the X-axis direction, and the vertical axis represents the intensity. The intensity distribution 50 satisfies the following condition. In the following description, an area where X≥0 is described as an example, but the same applies to an area where X≤0.

(a) It has a linear change area 51 whose intensity changes linearly over 90%-10% of the maximum intensity I _max .

(b) a linear change area 51, may be a point symmetry with respect to a point (P) strength (0.5I _max) and 50% of the maximum intensity (I _max) on the intensity distribution. That is, when the position on the X-axis is the intensity of 50% of the maximum intensity (I _max) with X _{0 .5,} it can be a point symmetry with respect to the _{P (X 0 .5, 0.5I max} ).

Although the intensity distribution 50 should just satisfy | fill the conditions of said (a) and (b), it is more preferable to satisfy | fill the following conditions (c) and (d) further. Here, an explanation will be given with an example in which X≥0.

(c) A distance from the origin O in the X-axis direction, which is 50% of the maximum intensity I _max , is defined as w ₁ (= X _0.5 ), and 90% of the maximum intensity I _max is obtained. When the distance from the origin (O) in the X-axis direction is set to w ₂ , and the distance from the origin (O) in the X-axis direction, which becomes an intensity of 10% of the maximum intensity (I _max ), is defined as w ₃ , The absolute value of the difference between ₁ and w ₂ or the absolute value w ₄ of the difference between w ₁ and w ₃ is equal to or greater than a predetermined length l. Here, the predetermined length l is ₁ w / 10 is illustrated, preferably ₁ w / 8, more preferably, w _1/6.

(d) In the intensity distribution 50, the region from the maximum intensity I _max to the foot is point symmetrical with respect to the point P (X _0.5 , 0.5I _max ).

By having condition (d), condition (b) is satisfied. As described above, the intensity distribution 50 may satisfy the conditions (a) and (b), but in the following description, the convex portions 41 are conditions (a) to unless otherwise specified. The intensity distribution satisfying (d) is realized. In FIG. 3, the intensity distribution 50 exemplifies a trapezoidal shape, in other words, a mountain shape having a flat top portion, but the present invention is not limited thereto. For example, the intensity distribution 50 may be a triangular shape called a mountain shape tapering toward the top side. In FIG. 5, the intensity distribution 50 is symmetrical with respect to the position of the origin O, but in the regions where X is positive and negative with respect to the origin O, the above conditions (a) to (c) Should just satisfy conditions (a)-(d).

With reference to FIG. 6, an example of the intensity distribution measuring method for verifying whether the light-diffusion plate 40 is realizing the intensity distribution 50 shown in FIG. 5 is demonstrated. It is a figure which shows an example of the intensity distribution measuring method.

As shown in FIG. 6, the measurement light source 31 _exam is disposed away from the first surface 40a by a predetermined distance D ₀ . As the light source 31 _exam , a linear light source such as CCFL or a point light source such as LED can be exemplified. The distance D ₀ may be 100 mm. Then, a light detector outputs light from the light source 31 _exam , moves the light diffusion plate 40, and arranges the light emitted from the second surface 40b to the second surface 40b side (not shown). To be detected. At this time, the photodetector is arranged to detect light output in the normal direction of the first surface 40a. In the following description, the normal direction of the first surface 40a is also referred to as the front direction.

In the transmissive image display apparatus 1 (for example, liquid crystal display device), the distance D between the light source 31 and the light diffusion plate 40 is usually 3 mm to 50 mm. On the other hand, the width of the convex portion 41 is usually 800 µm or less, preferably 10 µm or more and 800 µm or less, and more preferably 20 µm or more and 600 µm or less. Thus, when applying the light-diffusion plate 40 to the transmissive image display apparatus 1 etc., the distance D is large enough with respect to the magnitude | size of the convex part 41. FIG. Thus, by arranging the light source 31 _exam at a distance sufficiently long with a distance D ₀ of 100 mm as described above, the intensity distribution for verification is measured, whereby the actual surface light source device 20 or the transmissive image display device 1 It is considered that the same intensity distribution can be realized even in the arrangement. Therefore, the light diffusion plate 40 should just be satisfied that the intensity distribution obtained by detecting by the said measuring method satisfy | fills conditions (a)-(d).

The light diffusing plate 40 having the convex portions 41 satisfying the above conditions (a) to (d) can be manufactured as follows. An example of the manufacturing method of the light-diffusion plate 40 is demonstrated. In the manufacture of the light diffusing plate 40, there is provided a step of determining the cross-sectional shape of the convex portion 41 and a step of manufacturing the light diffuser plate 40 having the convex portion 41 of the cross-sectional shape determined at the crystallization step. .

(Determination process of cross-sectional shape)

The cross-sectional shape of the convex portion 41 can be designed to obtain a desired intensity distribution using a simulation based on the ray tracing method. An example of the cross-sectional shape determination method of the convex part 41 is demonstrated more concretely. Here, three approximations are adopted for the simulation.

Simulation is performed in a plane perpendicular to the light source 31.

The light source 31 is a point light source, that is, the diameter of the light source is zero.

Consider only direct transmitted light.

In the simulation, a simulation model as shown in FIG. 7 is adopted. That is, the cross-sectional shape model of the light diffusing plate 40 before the convex portion 41 is formed is represented by a rectangle 60, and is positioned at a predetermined distance D from the first side 60a of the rectangle 60. It is assumed that there is a light source 31. The predetermined distance D is determined depending on, for example, the surface light source device 20 and the transmissive image display device 1 that assume the application of the light diffusion plate 40. As described above, the distance D can be selected from 3 mm to 50 mm, for example.

Under the above approximation and model, for example, the cross-sectional shape of the convex portion 41 is determined as follows.

(Step 1) As shown in FIG. 8, as a function of the distance from the light source 31, the angle of the second side 60b of the rectangle 60 to direct the transmitted light of the rectangle 60 in the front direction. Obtain the inclination at the exit position, respectively. This tilt determination method can be the same as the method used in the design method of the Fresnel lens. The inclination is determined with respect to the unit line element 61 of the 2nd side 60b. In FIG. 8, a part of the process of calculating the inclination is shown typically.

(Step 2) The amount of incident light per unit line element 61 at the incident position of light to the rectangle 60, the transmittance, and the transmittance at the exit position are determined, and the amount of emitted light per unit line element 61 for each inclination is obtained.

(Step 3) The magnitude | size of the unit line element 61 with respect to each inclination is adjusted, and it determines so that a front intensity distribution may become desired intensity distribution.

By the said steps 1-3, the cross-sectional shape of the convex part 41 which can implement | achieve a desired intensity distribution with respect to a front direction can be designed.

Since the human eye and the like have a constant size, light is usually detected within a predetermined angular width (eg, ± 2.5 °) based on the normal direction of the first side 60a of FIG. 8. Therefore, also in the design of the cross-sectional shape of the convex part 41, after designing the cross-sectional shape in the said steps 1-3, for example, the convex part so that the intensity distribution obtained by integrating the intensity within a predetermined angular width may become desired intensity distribution. It is preferable to modify the shape of (41). In addition, in the design of the cross-sectional shape of the said convex part 41, the contour approximation of the cross-sectional shape obtained by the design process illustrated by steps 1-3 may be made the curve approximation, such as ellipse approximation.

(Manufacture process)

The light diffusion plate 40 is manufactured based on the convex portion 41 having the cross-sectional shape determined as described above. The light diffusion plate 40 can be produced by, for example, a method of cutting out from a transparent material. In addition, when using a transparent resin material as a transparent material, it can manufacture by methods, such as the injection molding method, the extrusion molding method, the press molding method, the photopolymer method, etc., for example.

Next, the case where the light diffusing plate 40 is applied to the surface light source device 20 and the transmissive image display device 1 will be described with respect to the effect of the light diffusing plate 40.

In the case where the light diffusing plates 40 are disposed on the light sources 31 (see FIG. 1), the light from each light source 31 has an intensity having a linear change region 51 as shown in FIG. 5. Distributions 50 are formed respectively. In the region between two adjacent light sources 31 and 31, the intensity distribution of light output mainly from the two light sources 31 and 31 and passing through the light diffusion plate 40 overlaps each other. The intensity distribution by 31) is formed.

Since the intensity distribution from each light source 31 has a linear change area 51 which satisfies the condition (b), the intensity distribution 50 of each light source 31 between two adjacent light sources 31 and 31. The linear change area 51 of) mainly overlaps. As a result, the intensity uniformity between two adjacent light sources 31 and 31 can be achieved, and the influence on the intensity distribution with respect to the change of L / D can be reduced. Therefore, for example, when the light diffusing plate 40 is applied to the surface light source device 20 or the transmissive image display device 1, the light source 31 and the light diffusing plate 40 which accompany changes in the environment, such as temperature, and thinning. The influence of the design change such as the distance between the windows and the arrangement of the light sources 31 is small, and a more stable brightness uniformity can be realized. This will be described in detail with reference to FIGS. 9, 10, and 11.

9 is a diagram illustrating an example of an intensity distribution between two adjacent light sources. In the figure, the horizontal axis has shown the position of the X-axis direction (2nd direction) at the time of the position of one light source 31 as a reference. In FIG. 9, the light sources 31 and 31 are arrange | positioned at X = 0 and 50, respectively, and the distance L between two light sources 31 and 31 is 50 mm. The vertical axis represents the normalized intensity normalized to the maximum intensity I _{max in} the intensity distribution 50 from one light source 31. In addition, the solid lines I and II in the figure have shown the intensity distribution by each light source 31 arrange | positioned at X = 0, 50. FIG. The broken line in the figure shows the result of overlapping the intensity distribution of the two light sources 31 and 31.

The intensity distribution by each light source 31 and 31 shown by the solid lines I and II in FIG. 9 is the intensity distribution 50 which has the linear change area | region 51, and in each intensity distribution, the maximum intensity _Imax ), The distance in the X-axis direction from the standardized intensity 1 in the drawing to the intensity 0 is equal to the distance between the two light sources 31 and 31. Therefore, in the intensity distribution by the plurality of light sources 31 and 31, the intensity distributions of two adjacent light sources 31 and 31 overlap each other. Further, two light sources (31, 31) the distance (L) is, X axis direction to the 0.5I _max from the maximum intensity (I _max) is in the intensity distribution (50) of each light source (31, 31) between the Equal to twice the distance. In this case, since the linear change region 51 has the condition (b) or (d), the intensity reduction from the maximum intensity I _max at the position in the X-axis direction with respect to one light source 31 is different from the other. The intensity of the light from the light source 31 supplements. As a result, as shown in Fig. 9, almost constant intensity distribution can be realized as the intensity distribution by the two light sources 31 and 31, and the luminance nonuniformity can be suppressed.

10 is a diagram illustrating another example of the intensity distribution between two adjacent light sources. In FIG. 10, the horizontal axis and the vertical axis are the same as those in FIG. 9. In FIG. 10, light sources 31 and 31 are arranged at X = 0 and 40, respectively, and the distance L between the two light sources 31 and 31 is 40 mm. In addition, the solid lines I and II in the figure represent the intensity distributions of the light sources 31 and 31 arranged at X = 0 and 40, respectively. The solid line III shows a part of the intensity distribution from the light source 31 arranged at X = 40 to another neighboring light source 31, that is, the light source 31 arranged at X = 80 (not shown). . Similarly, the solid line IV shows a part of the intensity distribution by another neighboring light source 31 of the light source 31 as a reference, that is, the light source 31 arranged at X = -40. The broken line indicates the intensity distribution between two adjacent light sources 31 and 31.

In FIG. 10, the intensity distribution by each light source 31 is an intensity distribution similar to the intensity distribution shown in FIG. Therefore, the length from the maximum intensity I _max to the intensity 0 becomes longer than the distance L between two adjacent light sources 31 and 31. Therefore, in the intensity distribution between two adjacent light sources 31 and 31, as shown by solid lines III and IV, another neighboring light source of each light source 31 disposed at X = 0, 40 ( The intensity distribution by 31) also contributes. In addition, since the distance L between the two light sources 31 and 31 is shorter than in the case of FIG. 9, the overlap of the linear variation region 51 of the intensity distribution by each of the two adjacent light sources 31 becomes large. Therefore, the intensity between two adjacent light sources 31 and 31 tends to increase as compared with the case of FIG. In FIG. 10, the intensity distribution of the four light sources 31 continuous in the X direction contributes to the intensity distribution between X = 0 to 40, but the intensity distribution of the light sources 31 and 31 disposed at X = 0 and 40. The overlap of is more dominant, and in the overlap of these intensity distributions, the linear change regions 51 overlap. Therefore, as in the case of FIG. 9, the intensity tends to be substantially constant between two adjacent light sources 31 and 31.

11 is a diagram illustrating still another example of the intensity distribution between two adjacent light sources. In FIG. 11, the horizontal axis and the vertical axis are the same as those in FIG. 9. In FIG. 11, the light sources 31 and 31 are arrange | positioned at X = 0 and 60, respectively, and the distance L between two light sources 31 and 31 is 60 mm. Solid lines I and II in the figure show intensity distributions by two adjacent light sources 31 and 31, respectively. The broken line indicates the intensity distribution between two adjacent light sources 31 and 31.

In FIG. 11, the intensity distribution by each light source 31 is an intensity distribution similar to the intensity distribution shown in FIG. Therefore, the length from the maximum intensity I _max to the intensity 0 is shorter than the distance L between two adjacent light sources 31 and 31. In this case, since the overlap of the intensity distribution of each light source 31 and 31 becomes small between two adjacent light sources 31 and 31, each light source 31 between two adjacent light sources 31 and 31 becomes small. The strength decreases as compared to just above. However, the overlap of the linear change regions 51 makes it possible to compensate for the decrease in the intensity by one light source 31 with the intensity by the other light source, so that the decrease in intensity is suppressed as compared with the case where the intensity decreases nonlinearly. can do.

As described above, with respect to the light diffusion plate 40 having the convex portion 41 capable of realizing the intensity distribution 50, the L / D is adjusted to be almost uniform between the two light sources 31 and 31. One intensity distribution can be realized (see FIG. 9). In addition, even if it deviates from the L / D adjusted in this way, it is possible to suppress the change of intensity distribution (refer FIG. 10 and FIG. 11). As described above, in the light diffusion plate 40, since the influence on the intensity distribution (or the luminance distribution) to the change in L / D is small, the light diffusion plate 40 has a versatility.

In addition, since the light diffusing plate 40 has the effects described above, in the surface light source device 20 having the light diffusing plate 40, it is possible to output the planar light of a high brightness uniformity and at the same time, A stable luminance uniformity can be realized. In addition, since the light diffusing plate 40 has the versatility as described above, the light diffusing plate 40 is changed depending on the arrangement of the light sources 31 and the change of the distance D between the light source 31 and the light diffusing plate 40. The need to prepare new) is reduced. Therefore, in the surface light source device 20 using the light diffusion plate 40, it is also possible to reduce the manufacturing cost of the surface light source device 20 while realizing a higher luminance uniformity. In addition, in the transmissive image display apparatus 1 provided with the light-diffusion plate 40, since the transmissive image display part 10 can be illuminated by the light with a high brightness uniformity, it is possible to display the image with a good image quality. In addition, since the light diffusing plate 40 has the versatility as described above, similarly to the case of the surface light source device 20, the arrangement of the light source 31 and the distance between the light source 31 and the light diffusing plate 40 ( According to the change of D), the necessity of newly preparing the light-diffusion plate 40 is reduced. As a result, it is also possible to reduce the manufacturing cost of the transmissive image display device 1 while realizing display of an image having good image quality.

(Third embodiment)

Next, with reference to FIGS. 12-39, another example of the shape of the convex part 41 which the light-diffusion plate 40 shown in FIG. 1 has is demonstrated. The convex portions 41 shown in Figs. 12, 18, 24, 26, 28, 30, 32, 34, 36, and 38 are called convex portions 41A to 41J, respectively. In description of each convex part 41A-41J, since it is the same as that of 1st Embodiment except the cross-sectional shape of the convex part 41A-41J, the same code | symbol is attached | subjected to the same element as 1st Embodiment as mentioned above. The cross-sectional shape which is different point is demonstrated. In addition, in the following description, it demonstrates using the local xz coordinate system set similarly to the case of FIG. The x axis constituting the xz coordinate system is an axis parallel to the array direction (second direction) of the plurality of convex portions 41, and the z axis is an axis line parallel to the plate thickness direction (direction perpendicular to the first and second directions). to be.

(Convex part 41A)

It is a figure which shows an example of the cross-sectional shape orthogonal to the extending direction of a convex part, and expands and shows one convex part.

In the xz plane of the xz coordinate system, both ends 41a and 41a of the convex portion 41A are located on the x-axis. The contour of the convex portion 41A is represented by z (x) that satisfies the following expression (5).

However, in Equation 5, z ₀ (x) is represented by Equation 6.

In Formula (6), w _a is the length in the x-axis direction of the convex portion 41. Furthermore, h is _a constant selected from _a range of 0.4825w ≤h _a ≤0.521w _a, k is _a constant selected from a range of -0.232≤k _a ≤-0.227. An example of h _a , k _a is h _a = 0.521w _a , k _a = -0.227. h _a corresponds to the maximum height in the z-axis direction between both ends 41a and 41a of the convex portion 41A in the case where the convex portion 41A is set to a shape represented by z ₀ (x). . K _a is a parameter representing the pointed side of the convex portion 41A. h _a and k _a being the maximum height as described above and the parameter indicating the sharp side are the same in the convex portions 41B to 41J described later. In FIG. 12, when h _a = 0.521w _a and k _a = -0.227, _a shape in which z ₀ (x) is stretched by a predetermined number (for example, 1 time) in the z direction within a range satisfying Equation 5 is shown. To illustrate. In this case, the top portion 41b is located on the z axis and has a contour symmetrical with respect to the z axis.

On the other hand, the outline of the convex portion 41A is not limited to the shape in which z ₀ (x) is stretched by a predetermined number (for example, 1 time) in the z direction, and the expression (5) may be satisfied. Therefore, as shown in FIG. 13, the outline of 41 A of convex-shaped parts is 1.05z and the outline represented by 0.95z ₀ (x), when z ₀ (x) is determined about the width w _a . _It is sufficient if the contour passes through the area between the contour lines represented by ₀ (x).

14-17, the shape example of a contour line is shown to the shape example 1 and the shape example 2 further more concretely. 14-17, the horizontal axis | shaft has shown the position (micrometer) with respect to an origin, and the vertical axis | shaft has shown the height (micrometer). 14 is a diagram illustrating z ₀ (x) in the shape example 1. FIG. In the shape example 1, to _{w a = 400㎛, h a =} 0.521w a, k a = -0.227. Z ₀ (x) determined by these values is called z1 ₀ (x) for convenience. In FIG. 14, the outline shape in the case of z (x) = z1 ₀ (x) is shown. When z1 ₀ (x) shown in FIG. 14 is made into outline shape, the outline shape shown in FIG. 14 and the outline shape illustrated in FIG. 12 are the same. Conditions satisfying the contour line based on z1 ₀ (x) are as shown in FIG. 15. FIG. 15 is a diagram for explaining a condition that the outline of Shape Example 1 satisfies. FIG. In FIG. 15, the outline represented by z1 ₀ (x), the outline represented by 0.95z1 ₀ (x), and the outline represented by 1.05z1 ₀ (x) are shown, and the outline may satisfy the equation (5). , may be as long as passing through the region between the contour represented by the contour and 1.05z1 ₀ (x) represented by 0.95z1 ₀ (x).

16 is a diagram illustrating z ₀ (x) in the shape example 2. FIG. In Configuration Example 2, w _a = 400 µm, h _a = 0.4825 w _a , and k _a = -0.232. Refers to z ₀ (x) for setting in the configuration example 2 in order to distinguish the case of the shape examples 1 to z2 ₀ (x). In FIG. 16, the outline shape in the case of z (x) = z2 ₀ (x) is shown. Conditions satisfying the contour line based on z2 ₀ (x) are as shown in FIG. 17. It is a figure for demonstrating the condition which the contour of the shape example 2 satisfy | fills. In FIG. 17, the outline represented by z2 ₀ (x), the outline represented by 0.95z2 ₀ (x), and the outline represented by 1.05z2 ₀ (x) are shown, and the outline may satisfy the equation (5). , may be as long as passing through the region between the contour represented by the contour and 1.05z2 ₀ (x) represented by 0.95z2 ₀ (x).

(Convex part 41B)

FIG. 18 is a diagram illustrating another example of a cross-sectional shape orthogonal to the extending direction of the convex portion, and is shown by enlarging one convex portion. The shape of the convex portion 41B is the same as that of the convex portion 41A except that the range of h _a and k _{a in} the equation (5) differs from the range of the convex portion 41A. It demonstrates centering around this difference.

The outline of the convex portion 41B is represented by z (x) that satisfies the expression (5) described for the convex portion 41A. In short, the convex portion (41B), and h is _a constant selected from _a range of 0.5966w ≤h _a ≤0.6837w _a according to Equation 6, k is _a range of from -0.075≤k _a ≤-0.069 Constant to be chosen. An example of h _a , k _a is h _a = 0.5966w _a , k _a = -0.075. In FIG. 18, as h _a = 0.5966w _a and ka = -0.075, a shape in which z ₀ (x) is stretched by a predetermined number (for example, 1 time) in the z direction within a range satisfying Equation 5 is illustrated. Doing.

On the other hand, the outline of the convex portion 41B is not limited to the shape in which z ₀ (x) is stretched by a predetermined number (for example, 1 time) in the z direction, and the expression (5) may be satisfied. Therefore, as shown in FIG. 19, the outline of the convex part 41B is 1.05z and the outline represented by 0.95z ₀ (x), when z ₀ (x) is determined about the width w _a . _It is sufficient if the contour passes through the area between the contour lines represented by ₀ (x).

20-23, the shape example of an outline is concretely shown as the shape example 3 and the shape example 4. FIG. In FIGS. 20-23, the horizontal axis | shaft and the vertical axis | shaft are the same as the case of FIGS. 14-17. 20 is a diagram illustrating z ₀ (x) in the configuration example 3. FIG. In the shape example 3, it is set as w _a = 400 micrometers, h _a = 0.5966w _a , k _a = -0.075. A z ₀ (x) which is determined by these values is taken for convenience by referred to as z3 ₀ (x). In FIG. 20, the outline shape in the case of z (x) = z3 ₀ (x) is shown. In FIG. 18, the case where z3 ₀ (x) is outlined is shown as an example. Conditions satisfying the contour line based on z3 ₀ (x) are as shown in FIG. 21. FIG. 21 is a diagram for explaining a condition that the contour of Form 3 is satisfied. FIG. In FIG. 21, the outline represented by z3 ₀ (x), the outline represented by 0.95z3 ₀ (x), and the outline represented by 1.05z3 ₀ (x) are shown, and the outline may satisfy the equation (5). , may be as long as passing through the region between the contour represented by the contour and 1.05z3 ₀ (x) represented by 0.95z3 ₀ (x).

22 is a diagram illustrating z ₀ (x) in the configuration example 4. FIG. In the shape example 4, and a _{w a = 400㎛, h a =} 0.6837w a, k a = -0.069. Refers to z ₀ (x) for setting in the configuration example 4, in order to distinguish the case of the shape examples 3 to z4 ₀ (x). In FIG. 22, the outline shape in the case of z (x) = z4 ₀ (x) is shown. The condition that the outline based on z4 ₀ (x) is satisfied is as shown in FIG. It is a figure for demonstrating the condition which the contour of the shape example 4 satisfy | fills. In FIG. 23, the outline represented by z4 ₀ (x), the outline represented by 0.95z4 ₀ (x), and the outline represented by 1.05z4 ₀ (x) are shown, and the outline may satisfy the equation (5). , may be as long as passing through the region between the contour represented by the contour and 1.05z4 ₀ (x) represented by 0.95z4 ₀ (x).

(Convex shape part 41C)

It is a figure which shows the other example of the cross-sectional shape orthogonal to the extension direction of a convex part, and expands and shows one convex part. The shape of the convex portion 41C is the same as that of the convex portion 41A except that h _a and k _a in Equation 6 are different from the convex portion 41A. It demonstrates centering around this difference.

The outline of the convex portion 41C is represented by z (x) that satisfies the expression (5) described for the convex portion 41A. However, in the convex portion 41C, h _a = 0.434w _a and k _a = -0.24 in the expression (6). In FIG. 24, the shape which expanded and contracted z ₀ (x) by the predetermined | prescribed times (for example, 1 time) in the z direction in the range which satisfy | fills Formula (5) is illustrated. In this case, both ends 41a and 41a are located on the x-axis, and the top part 41b is located on the z-axis. The convex portion 41 also has an outline symmetrical with respect to the z axis.

On the other hand, the contour of the convex portion 41C is not limited to the shape in which z ₀ (x) is stretched by a predetermined number (for example, 1 time) in the z direction, and the expression (5) may be satisfied. Therefore, as shown in Fig. 25, the contour lines of the convex portion 41C are outlines represented by 0.95z ₀ (x) and 1.05z when z ₀ (x) is determined for _a certain width w _a . _It is sufficient if the contour passes through the area between the contour lines represented by ₀ (x).

(Convex part 41D)

It is a figure which shows the other example of the cross-sectional shape orthogonal to the extension direction of a convex part, and expands and shows one convex part. The shape of the convex portion 41C is the same as that of the convex portion 41A except that h _a and k _a in Equation 6 are different from the convex portion 41A. It demonstrates centering around this difference.

The outline of the convex portion 41D is represented by z (x) that satisfies the expression (5) described for the convex portion 41A. However, in the convex portion 41B, h _a = 0.614w _a and k _a = -0.17 in the expression (6). In FIG. 26, the shape which expanded and contracted z ₀ (x) by predetermined times (for example, 1 time) in a z direction in the range which satisfy | fills Formula (5) is illustrated. In this case, both ends 41a and 41a are located on the x-axis, and the top part 41b is located on the z-axis. The convex portion 41 also has an outline symmetrical with respect to the z axis.

On the other hand, the outline of the convex portion 41D is not limited to a shape in which z ₀ (x) is stretched by a predetermined number (for example, 1 time) in the z direction, and the expression (5) may be satisfied. Therefore, as shown in Fig. 27, the contour lines of the convex portion 41D are outlines represented by 0.95z ₀ (x) and 1.05z when z ₀ (x) is determined for _a certain width w _a . _It is sufficient if the contour passes through the area between the contour lines represented by ₀ (x).

(Convex part 41E)

It is a figure which shows the other example of the cross-sectional shape orthogonal to the extension direction of a convex part, and expands and shows one convex part. The shape of the convex portion 41E is the same as that of the convex portion 41A except that h _a and k _a in Equation 6 are different from the convex portion 41A. It demonstrates centering around this difference.

The outline of the convex portion 41E is represented by z (x) that satisfies the expression (5) described for the convex portion 41A. However, in the convex portion 41E, h _a = 0.588w _a and k _a = -0.128 in the expression (6). In FIG. 28, the shape which expanded and contracted z ₀ (x) by predetermined times (for example, 1 time) in a z direction in the range which satisfy | fills Formula (5) is illustrated. In this case, both ends 41a and 41a are located on the x-axis, and the top part 41b is located on the z-axis. In addition, the convex portion 41E has an outline symmetrical with respect to the z axis.

On the other hand, the outline of the convex portion 41E is not limited to the shape in which z ₀ (x) is stretched by a predetermined number (for example, 1 time) in the z direction, and the expression (5) may be satisfied. Therefore, as shown in Fig. 29, the contour lines of the convex portion 41E are outlines represented by 0.95z ₀ (x) and 1.05z when z ₀ (x) is determined for _a certain width w _a . _It is sufficient if the contour passes through the area between the contour lines represented by ₀ (x).

(Convex shape part 41F)

It is a figure which shows the other example of the cross-sectional shape orthogonal to the extending direction of a convex part, and expands and shows one convex part. The shape of the convex portion 41F is the same as that of the convex portion 41A except that h _a and k _a in Equation 6 differ from the convex portion 41A. It demonstrates centering around this difference.

The outline of the convex portion 41F is represented by z (x) that satisfies the expression (5) described for the convex portion 41A. However, in the convex portion 41F, h _a = 0.578w _a and k _a = -0.081 in the expression (6). In FIG. 30, the shape which expanded and contracted z ₀ (x) by the predetermined | prescribed times (for example, 1 time) in the z direction in the range which satisfy | fills Formula (5) is illustrated. In this case, both ends 41a and 41a are located on the x-axis, and the top part 41b is located on the z-axis. In addition, the convex portion 41F has an outline symmetrical with respect to the z axis.

On the other hand, the contour of the convex portion 41F is not limited to the shape in which z ₀ (x) is stretched by a predetermined number (for example, 1 time) in the z direction, and the expression (5) may be satisfied. Therefore, as shown in Fig. 31, the contour lines of the convex portion 41F are outlines represented by 0.95z ₀ (x) and 1.05z when z ₀ (x) is determined for _a certain width w _a . _It is sufficient if the contour passes through the area between the contour lines represented by ₀ (x).

(Convex part 41G)

FIG. 32 is a diagram illustrating another example of a cross-sectional shape orthogonal to the extending direction of the convex portion, and is shown by enlarging one convex portion. The shape of the convex portion 41G is the same as the shape of the convex portion 41A except that h _a and k _a in Equation 6 differ from the range of the convex portion 41A. It demonstrates centering around this difference.

The outline of the convex portion 41G is represented by z (x) that satisfies the expression (5) described for the convex portion 41A. However, in the convex portion 41G, h _a = 0.550w _a and k _a = -0.082 in the expression (6). In FIG. 32, the shape which expanded and contracted z ₀ (x) by predetermined times (for example, 1 time) in a z direction in the range which satisfy | fills Formula (5) is illustrated. In this case, both ends 41a and 41a are located on the x-axis, and the top part 41b is located on the z-axis. The convex portion 41G also has an outline symmetrical with respect to the z axis.

On the other hand, the contour of the convex portion 41G is not limited to the shape in which z ₀ (x) is stretched by a predetermined number (for example, 1 time) in the z direction, and the expression (5) may be satisfied. Therefore, as shown in Fig. 33, the contour of the convex portion 41G is defined as 0.95z ₀ (x) and 1.05z when z ₀ (x) is determined for _a certain width w _a . _It is sufficient if the contour passes through the area between the contour lines represented by ₀ (x).

(Convex part 41H)

34 is a diagram illustrating another example of the cross-sectional shape orthogonal to the extending direction of the convex portion, and is shown by enlarging one convex portion. The shape of the convex portion 41H is the same as the shape of the convex portion 41A except that h _a and k _a in Equation 6 differ from the convex portion 41A. It demonstrates centering around this difference.

The outline of the convex portion 41H is represented by z (x) that satisfies the expression (5) described for the convex portion 41A. However, in the convex portion 41H, h _a = 0.560w _a and k _a = -0.127 in the equation (6). In FIG. 34, the shape which expanded and contracted z ₀ (x) by the predetermined | prescribed times (for example, 1 time) in the z direction in the range which satisfy | fills Formula (5) is illustrated. In this case, both ends 41a and 41a are located on the x-axis, and the top part 41b is located on the z-axis. In addition, the convex portion 41H has an outline symmetrical with respect to the z axis.

On the other hand, the outline of the convex portion 41H is not limited to a shape in which z ₀ (x) is stretched by a predetermined number (for example, 1 time) in the z direction, and the expression (5) may be satisfied. Therefore, as shown in Fig. 35, the contour lines of the convex portion 41H are outlines represented by 0.95z ₀ (x) and 1.05z when z ₀ (x) is determined for _a certain width w _a . _It is sufficient if the contour passes through the area between the contour lines represented by ₀ (x).

(Convex part 41I)

36 is a diagram illustrating another example of a cross-sectional shape orthogonal to the extending direction of the convex portion, and is shown by enlarging one convex portion. The shape of the convex portion 41I is the same as that of the convex portion 41A except that h _a and k _a in Equation 6 are different from the convex portion 41A. It demonstrates centering around this difference.

The outline of the convex portion 41I is represented by z (x) that satisfies the expression (5) described for the convex portion 41A. However, in the convex portion 41I, h _a = 0.578w _a and k _a = -0.185 in the expression (6). In FIG. 36, the shape which expanded and contracted z ₀ (x) by the predetermined | prescribed times (for example, 1 time) in the z direction in the range which satisfy | fills Formula (5) is illustrated. In this case, both ends 41a and 41a are located on the x-axis, and the top part 41b is located on the z-axis. In addition, the convex portion 41I has an outline symmetrical with respect to the z axis.

On the other hand, the outline of the convex portion 41I is not limited to the shape in which z ₀ (x) is stretched by a predetermined number (for example, 1 time) in the z direction, and the expression (5) may be satisfied. Therefore, as shown in outline, and 37 of the convex portion (41I), when determining a z ₀ (x) with respect to which the width (w _a), contour and 1.05z represented by 0.95z ₀ (x) _It is sufficient if the contour passes through the area between the contour lines represented by ₀ (x).

(Convex shape part 41J)

FIG. 38 is a diagram illustrating another example of a cross-sectional shape orthogonal to the extending direction of the convex portion, and is shown by enlarging one convex portion. The shape of the convex portion 41J is the same as the shape of the convex portion 41A except that h _a and k _a in Equation 6 differ from the convex portion 41A. It demonstrates centering around this difference.

The outline of the convex portion 41J is represented by z (x) that satisfies the expression (5) described for the convex portion 41A. However, in the convex portion 41J, h _a = 0.486w _a and k _a = -0.144 in the expression (6). In FIG. 38, the shape which expanded and contracted z ₀ (x) by predetermined times (for example, 1 time) in a z direction in the range which satisfy | fills Formula (5) is illustrated. In this case, both ends 41a and 41a are located on the x-axis, and the top part 41b is located on the z-axis. In addition, the convex portion 41J has an outline symmetrical with respect to the z axis.

On the other hand, the outline of the convex portion 41J is not limited to the shape in which z ₀ (x) is stretched by a predetermined number (for example, 1 time) in the z direction, and the expression (5) may be satisfied. Therefore, as shown in Fig. 39, the contour of the convex portion 41J is 1.05z and the contour represented by 0.95z ₀ (x) when z ₀ (x) is determined for _a certain width w _a . _It is sufficient if the contour passes through the area between the contour lines represented by ₀ (x).

As the width (w _a) of said convex portion _{(41A~41J), w a = 410㎛} , there can be mentioned a _{w a = 400㎛, w a =} 353㎛ or w _a = 325㎛. Similarly, the shape of eg 1, 2, 3, and 4 were described as _a w = 400㎛. w is the value of _a does not limited to these, and w _a is not more than 800㎛ preferable, and a range from 10㎛ 800㎛ preferable, and further more preferably not more than more than 600㎛ 20㎛.

In the above description, the cross-sectional shape of the convex portions 41A to 41J is represented by z (x) that satisfies the expression (5). However, in consideration of the manufacturing error and the influence on the intensity distribution in the vicinity of both ends of the convex portions 41A to 41J, the cross-sectional shape of the convex portions 41A to 41J is -0.5w _a × 0.95≤x≤ It may be represented by z (x) satisfying equation (5) at 0.5w _a × 0.95, and more preferably represented by z (x) satisfying equation (5) at −0.5w _a ≦ x ≦ 0.5w _a .

As mentioned above, although the convex part 41A-41J applied to the light-diffusion plate 40 shown in FIG. 1 was further demonstrated, the shape examples 1, 2, and convex shape of the convex part 41A were demonstrated. Shape examples 3 and 4 of the portion 41B and the convex portions 41C to 41J correspond to one example of the convex portion 41 of the first embodiment. In addition, r times the convex portion (41A) and the convex portion in (41B), the convex portion (41A, 41B) showing _a h and k z _{a 0} (x) in the range with respect to (r is 0.95~ The shape having a number of 1.05 and the allowable fluctuation range of 0.01 w _{a for} the shape correspond to the convex portion 41 of the first embodiment.

Effects of the light diffusing plate 40 having the convex portions 41A to 41J, the surface light source device 20 having the light diffusing plate 40 and the transmissive image display device 1 will be described. . In the first embodiment, the light diffusing plate 40 having the convex portions 41A to 41J, and the surface light source device 20 and the transmissive image display device 1 having the light diffusing plate 40 are provided. It has an effect similar to the effect described. Hereinafter, the effect will be briefly described. The convex portions 41A to 41J are referred to as the convex portions 41.

Light emitted from each light source 31 and incident on the light diffusion plate 40 is directed toward the transmissive image display unit 10 through the convex portion 41 having a cross-sectional shape represented by z (x). It is emitted. By the diffusing action by the convex portion 41 having a cross-sectional shape represented by z (x), the light from the light source 31 is diffused to produce planar light and the luminance unevenness is suppressed. Therefore, the image of the light source 31 is not projected on the transmissive image display part 10. And by having the convex part 41 whose cross-sectional shape is represented by the said z (x), it is also possible to implement | achieve higher luminance uniformity of a front direction.

In addition, since the cross-sectional shape of the convex portion 41 is represented by z (x) that satisfies the expression (5), for example, L due to deformation due to position shift or heat with respect to the light source 31 of the light diffusion plate 40, etc. Even if / D fluctuates from a predetermined value (for example, a design value), luminance unevenness hardly occurs, and the luminance unevenness can be suppressed more stably.

Therefore, in the surface light source device 20 provided with the light diffusing plate 40, it is possible to more stably output light in which luminance unevenness is suppressed. And in the transmissive image display apparatus 1 containing the light-diffusion plate 40, since the light in which the luminance nonuniformity was suppressed can illuminate the transmissive image display part 10, a light-diffusion plate is aimed at improving display quality. It is possible to suppress fluctuations in display quality due to deformation due to positional shift or heat to the light source 31 of 40.

In addition, each convex part 41A-41J implement | achieves the intensity distribution 50 demonstrated in 2nd Embodiment, and each convex part 41A-41J has the convex part 41 demonstrated in 2nd Embodiment. One embodiment of the. Therefore, the convex portions 41A to 41J have the same operation effects as those described in the second embodiment. Here, the light diffusion plate 40 having the convex portions 41A to 41J as an example of the convex portions 41 described in the second embodiment is applied to the surface light source device 20 and the transmissive image display device 1. The case will be described in detail. The convex portions 41A to 41J are referred to as the convex portions 41.

In the surface light source device 20 and the transmissive image display device 1 including the light diffusing plate 40 having the convex portion 41, the light output from each light source 31 of the light source unit 30 is directly Alternatively, the light is reflected from the inner surface 32a of the lamp box 32 and incident on the light diffusion plate 40. Light incident on the light diffusing plate 40 is irradiated toward the transmissive image display unit 10 from the second surface 40b. At this time, since a plurality of convex portions 41 are formed on the second surface 40b of the light diffusion plate 40, light is emitted through the convex portions 41. Since the convex portion 41 has a cross-sectional shape represented by z (x), the light is refracted in various directions depending on the passing position (emission position) of the light. By the diffusion effect, the light from the light source 31 is diffused to generate surface light, and the image of the light source 31 is not projected onto the transmissive image display unit 10.

And the cross-sectional shape of the convex part 41 is a part of the area | region which spreads from the top part of the intensity distribution to the foot part in the intensity distribution of the front direction of the light which entered the convex part 41 from one light source 31. FIG. This is one embodiment in the case where it is designed to have a region (linear change region 51) in which the intensity changes linearly (primarily functionally). Therefore, in the intensity distribution in the frontal direction of the light incident on the convex portion 41 from the light source 31, as described above, the region where the intensity changes linearly (primary function) (linear change region 51). Has Therefore, in the light diffusing plate 40 in which the convex part 41 was formed in multiple numbers, the luminance distribution of the light radiate | emitted from the light diffusing plate 40 becomes easy to be uniform, and luminance nonuniformity is suppressed and the light source 31 mentioned above is suppressed. It becomes harder to appear more. In addition, since the light emitted from the convex portion 41 has the above-mentioned intensity distribution characteristic, the change of the brightness uniformity is suppressed with respect to the change of L / D. As a result, the luminance nonuniformity can be suppressed more stably. In addition, since the influence of the brightness uniformity on the change in L / D is reduced, the light diffusion plate 40 has versatility.

Therefore, in the surface light source device 20 provided with the light diffusing plate 40, it is possible to output light in which luminance unevenness is suppressed. Further, in the surface light source device 20, the change in luminance uniformity is suppressed with respect to the change in L / D.

And in the transmissive image display apparatus 1 containing the light-diffusion plate 40, since the light in which the luminance nonuniformity was suppressed can illuminate the transmissive image display part 10, display quality can be improved.

[Example]

(Examples 1 to 12)

With reference to Examples 1-12 and the comparative example 1, a light-diffusion plate (light control board) is demonstrated concretely. In the following descriptions of Examples 1 to 12 and Comparative Example 1, for convenience of description, the convex portion is referred to as the convex portion 41, and the elements corresponding to the elements of the first embodiment are denoted by the same reference numerals. do.

In Examples 1-12 and Comparative Example 1, the intensity distribution was calculated | required by the ray tracing method about the cross-sectional shape of each convex-shaped part, respectively.

[Simulation method]

40 is a schematic diagram illustrating a simulation model. As shown in FIG. 40, in the simulation, the light diffusion plates 40 are disposed on the two light sources 31 and 31, and the intensity of the light output from the light sources 31 and 31 and passed through the light diffusion plates 40 is shown. Was observed. For the simulation, three approximations, i.e., simulation in a plane orthogonal to the light source 31, (ii) the light source 31 is a point light source, i.e., the diameter of the light source is zero, and (iii) A simulation was performed by the ray tracing method, taking into consideration only the direct transmitted light. For convenience of explanation, the two light sources 31 and 31 shown in FIG. 40 are referred to as a light source 31A and a light source 31B, respectively. This simulation method is the same as that of the simulation method in Examples 14-17 mentioned later and the calculation method of the quantity of incident light per unit length of the 1st surface 40a differs.

In all the simulations of Examples 1 to 12 and Comparative Example 1, the distance L between the two light sources 31A and 31B was 45 mm, the thickness d ₁ was 1.5, and the light diffusion plate 40 was used. The refractive index of was set to 1.59. In each simulation of Examples 1-12 and Comparative Example 1, the cross-sectional shape of the convex part 41 was designed by the determination process of the cross-sectional shape demonstrated in 2nd Embodiment. Specifically, after the steps 1 to 3 were performed under the above conditions, the cross-sectional shape of the convex portion 41 was calculated, predetermined interpolation was performed to obtain the cross-sectional shape of the convex portion 41. In the design, the distance D between the light source 31A (or the light source 31B) and the light diffusion plate 40 is set to a predetermined distance. D as this predetermined distance is set so that L / D becomes the next value when L = 45 mm. That is, L / D = 2.17 in Example 1, L / D = 2.50 in Example 2, L / D = 3.20 in Example 3, L / D = 3.75 in Example 4, and L / D = in Example 5 2.00, the distance D at design time is set so that L / D = 3.20 in Examples 6-8, L / D = 3.00 in Examples 9-11 and L / D = 2.50 in Example 12.

41 to 52 are diagrams showing design data at the design stage of the convex portion used in the simulations of Examples 1 to 12, respectively. The width w _a of the convex portion 41 is w _a = 400 µm for Examples 1 to 4, w _a = 250 µm for Example 5, and w _a = 355 µm for Examples 6-11. For Example 12, w _a = 349 µm. In FIGS. 41-52, x has shown the position (micrometer) on the x-axis in description of the convex part 41A-41J. In FIGS. 41-52, z represents the position (micrometer) on the z-axis in description of the convex-shaped parts 41A-41J, and corresponds to the height (micrometer) of the convex-shaped part 41. FIG. 41-52, the shape of half of the convex-shaped part 41 is designed in the design step by steps 1-3. Each data point represented by the x and z pairs shown in FIGS. 41 to 52 represents the intersection position of the adjacent line elements discretized in steps 1 to 3 described in the second embodiment.

The simulations in Examples 1 to 12 were performed on the cross-sectional shape of the convex portion 41 obtained by performing third-spline interpolation with each data point shown in FIGS. 41 to 52 as a vertex. In each of Figs. 41 to 52, the third-spline interpolation has twice the derivative at 0 at the left end of the convex portion 41, that is, (x, z) = (-w _a / 2, 0). At the apex part of the convex part 41, ie, the position where x = 0, it performs on the condition that one derivative is 0 once. In addition, in the simulation in the comparative example 1, the cross-sectional shape of the convex part 41 was made into the semicircle shape.

The cross-sectional shapes of the convex portions in Examples 1 to 12 and Comparative Example 1 correspond to those represented by z ₀ (x) shown in Equation (4) or (6). At this time, h _a and k _a are shown in Table 9. On the other hand, in Example width of the convex portion 41 of 1~12 _(a w) is the width (w _a), the convex portion 41 of the as defined above, Comparative Example 1 is the case of Examples 1 to 4 Similarly, it is 400 μm. In the case of the values of h _a and k _a shown in Table 9, the cross-sectional shape of Example 1 corresponds to Shape Example 2 shown in the third embodiment, and the cross-sectional shape of Example 2 corresponds to Shape Example 1. The cross-sectional shape of Example 3 corresponds to Shape Example 3 shown in the third embodiment, and the cross-sectional shape of Example 4 corresponds to Shape Example 4. In addition, the cross-sectional shape of Examples 5-12 corresponds to the convex part 41C-41J, respectively.

The following simulation A was performed about Examples 1-12 and Comparative Example 1 using the said simulation model.

(Simulation A)

By providing a periodic boundary condition, the intensity distribution in the area | region on two adjacent light sources 31A and 31B by the light output from the some light source 31 was calculated. In the result of this simulation 3, the calculation result in the area | region between two adjacent light sources 31A and 31B is shown. In this simulation A, while making distance L 45 mm, intensity distribution was calculated | required about different L / D by changing distance D. In FIG. And intensity homogenization (%) in the case of front direction ((theta) = 0) was calculated about different L / D. Intensity leveling agent (%) was calculated as "(minimum intensity) / (maximum intensity) x 100". On the other hand, since the intensity for a certain observation angle θ corresponds to the luminance, the intensity uniformity based on the intensity distribution for a certain observation angle θ corresponds to the luminance uniformity.

Simulation results are shown in the diagram shown in FIG. In Examples 1-12, intensity | strength uniformity (brightness uniformity) higher than Comparative Example 1 can be implement | achieved. Especially,

In Example 1, L / D = 2.17,

In Example 2, L / D = 2.5,

In Example 3, L / D = 3.15, 3.2,

In Example 4, L / D = 3.7, 3.75,

In Example 5, L / D = 2.0,

In Example 6, L / D = 3.2, 3.3,

In Examples 7, 8, L / D = 3.2,

L / D = 3.0 in Examples 9-11, and

In Example 12, L / D = 2.5

In this case, it is possible to realize a high strength homogenizer (brightness homogenizer) in the front direction of 90% or more.

(Example 13)

Example 13 was carried out by designing the convex portion 41 in the same manner as in Examples 1 to 12 except that the refractive index of the light diffusion plate 40 was set to 1.49 and the thickness d ₁ was set to 2.25. did. In Example 13, w _a = 400 μm. Design data at the design stage in Example 13 corresponding to FIGS. 41 to 52 is as shown in the diagram of FIG. 54. In the design of the convex portion 14 of the thirteenth embodiment, the distance D as a predetermined distance between the light source 31A (or the light source 31B) and the light diffusion plate 40 was set to L = 45 mm. The L / D is set to 4.00 at this time. Also in Example 13, predetermined interpolation processing is performed on these experimental data similarly to the case of Examples 1-12. Also in Example 13, the cross-sectional shape of the convex part 41 respond | corresponds to having set h _a = 0.9752w _a and k _a = -0.212 in z ₀ (x) shown in Equation (4) or (6). . On the other hand, w _a is 400 µm as described above. The simulation results of Example 13 are shown in the table.

From Table 10, it is possible to realize a high value of 90% or more of intensity uniformity (brightness leveling agent) at L / D 2.0 and 4.0, and to realize a high intensity leveling agent (brightness leveling agent) even at 4.0 having a larger L / D. .

(Examples 14 to 17)

Next, with reference to Examples 14-17 and the comparative example 2, a light-diffusion plate (light control board) is demonstrated concretely. In the following descriptions of Examples 14 to 17 and Comparative Example 2, the elements corresponding to the elements of the first embodiment are denoted by the same reference numerals for convenience of explanation.

In Examples 14 to 17 and Comparative Example 2, the intensity distribution was obtained by simulation by the ray tracing method on the cross-sectional shapes of the different convex portions, respectively. Since the simulation method is substantially the same as the case of Examples 1-12, it abbreviate | omits description. On the other hand, as mentioned above, the calculation method of the light quantity per unit length of the 1st surface 40a differs from the case of Examples 1-12. In all the simulations of Examples 14 to 17 and Comparative Example 2, the distance L between the two light sources 31A and 31B was 30 mm, and the refractive index of the light diffusion plate 40 was 1.59. In addition, the thickness d ₁ of the light diffusion plate 40 was 1.5 mm.

In each of the simulations of Examples 14 to 17 and Comparative Example 2, convex portions having cross-sectional shapes set in Examples 14 to 17 and Comparative Example 2 on the second surface 40b of the light diffusion plate 40. (41) was formed.

Using the simulation model, simulations 1 to 3 were performed for Examples 14 to 17 and Comparative Example 2.

(Simulation 1)

The intensity distribution of the front direction with respect to the light output from one light source 31A arrange | positioned at the position of predetermined distance D from the 1st surface 40a was calculated.

(Simulation 2)

The intensity distribution of the front direction with respect to the light output from one light source 31A arrange | positioned at the position of 100 mm from the 1st surface 40a was calculated.

(Simulation 3)

In the same manner as in the case of simulation A, the intensity distribution was obtained for different L / D. In simulation 3, intensity distribution in the case of observing light from the direction of the observation angle θ with respect to the frontal direction was also calculated. And intensity uniformity (%) was computed about different L / D and different observation angle (theta).

[Shape of Convex Shape]

In Examples 14 to 17, the distance D between the light source 31A (or the light source 31B) and the light diffusion plate 40 is set to a predetermined distance, and the convex portions 41 are formed so as to have a desired intensity distribution. The cross-sectional shape of the was designed. The predetermined distance is D = 13.82mm in the fourteenth embodiment, D = 12mm in the fifteenth embodiment, D = 9.375mm in the sixteenth embodiment, and D = 8.0mm in the seventeenth embodiment.

In Examples 14 to 17, the steps 1 to 3 described in the second embodiment are calculated under the above conditions to calculate the cross-sectional shape of the convex portion 41, and then predetermined interpolation is performed to perform the convex portion 41. The cross-sectional shape of was obtained. The widths of Examples 14 to 17 are the same. The design data at the design stage of the convex portion 41 used in each of the simulations 14 to 17 is the same as in the first to fourth embodiments. That is, FIGS. 41-44 is a table which shows the design data in the design stage of the convex-shaped part used by the simulation of Examples 14-17, respectively.

The simulation in Examples 14-17 was performed with respect to the cross-sectional shape of the convex part 41 obtained by performing 3rd spline interpolation using each data point shown in FIGS. 41-44 as a vertex. The third spline interpolation is, in each of Figs. 41 to 44, at the left end of the convex portion 41, that is, at (x, z) = (-200, 0), the second derivative is 0 and the convex portion. At the vertex portion of (41), that is, the position where x = 0, the first derivative is performed under the condition that the derivative is zero. In addition, in the simulation in the comparative example 2, the cross-sectional shape of the convex part 41 was made into the semicircle shape. In addition, the width of the comparative example 2 is the same as that of Examples 14-17.

55, the cross-sectional shape of the convex part 41 used for the simulation is shown. FIG. 55 is a diagram showing a cross-sectional shape of the convex portions of Examples 14 to 17 and Comparative Example 2. FIG. 55 corresponds to the x-axis in the description of the convex portions 41A to 41J, and indicates the position in the width direction of the convex portion 41. 55 represents the height corresponding to the z-axis in description of the convex part 41A-41J. The width | variety of the convex part 41 of Examples 14-17 and the comparative example 2 is the same. In addition, in FIG. 55, the length of the horizontal axis | shaft and the vertical axis | shaft is standardized and shown based on the half length of the width | variety of the both ends of the convex part 41. As shown in FIG.

The cross-sectional shape of the convex portions of Examples 14 to 17 shown in FIG. 55 is represented by z ₀ (x) when h _a and k _a are set as shown in Table 11 in Equation (4) or (6). Corresponds to the shape. In Table 11, w _a is 400 μm.

[Simulation Result]

Hereinafter, the simulation result of the simulation 1-3 of Examples 14-17 and the comparative example 2 is demonstrated. In description of a simulation result, the arrangement direction of the convex part 41, ie, a 2nd direction, is called an X-axis direction similarly to the case of 2nd Embodiment.

(Comparative Example 2)

FIG. 56 shows the results of simulation 1 in Comparative Example 2. FIG. In FIG. 56, the front direction intensity distribution with respect to the light from the light source 31A in the case where D = 12 (mm) is shown. 56 represents the position with respect to the light source 31A in the X-axis direction, and the vertical axis represents the intensity (arbitrary unit). 57 is a diagram showing the results of simulation 2 in Comparative Example 2. FIG. 57 represents the position with respect to the light source 31A in the X-axis direction, and the vertical axis represents the standardized intensity normalized to the maximum intensity.

As shown in FIG. 56 and FIG. 57, in the comparative example 2, intensity | strength changes nonlinearly from the top part to the foot part of intensity | strength distribution. That is, the intensity distribution by the light diffusion plate 40 having the convex portion 41 of Comparative Example 2 does not have the linear change region 51.

Table 12 shows an example of the results of simulation 3. In Table 12, the result of calculating the intensity | strength uniformity (brightness uniformity) (%) based on the intensity with respect to the position from the light source 31A is shown about L / D and observation angle (theta).

58A to 58C are diagrams showing the intensity distribution based on the result of simulation 3 in Comparative Example 2. FIG. FIG. 58A shows the intensity distribution with respect to the position and the observation angle θ with respect to the light source 31A when L / D = 3.5. FIG. 58 (b) shows the intensity distribution with respect to the position and the observation angle θ with respect to the light source 31A when L / D = 3.75. FIG. 58C shows the intensity distribution with respect to the position and the observation angle θ based on the light source 31A when L / D = 4.0.

(Example 14)

FIG. 59 is a diagram showing the results of simulation 1 in Example 14. FIG. In FIG. 59, the intensity distribution of the front direction with respect to the light from the light source 31A when D = 13.82 (mm) is shown. 59 shows the position with respect to the light source 31A in the X-axis direction, and the vertical axis | shaft has shown intensity (arbitrary unit). 60 shows the results of simulation 2 in Example 1. FIG. The horizontal axis of FIG. 60 shows the position with respect to the light source 31A in the X-axis direction, and the vertical axis | shaft has shown the normalized intensity similarly to the case of FIG.

As shown in FIG. 59 and FIG. 60, in the cross-sectional shape of the convex part 41 of Example 14, it turns out that it has the linear change area | region 51 from the top part to the foot part of intensity distribution. In addition, from FIG. 60, in Example 14, the intensity distribution under the conditions of simulation 2 also satisfies conditions (c) and (d) together with conditions (a) and (b). In addition, w ₄ can be said that satisfies w _1/6 or more in the condition (c).

Table 13 shows an example of the results of simulation 3. In Table 13, the result of having calculated the intensity uniformity (brightness uniformity) (%) based on the intensity | strength with respect to the position from the light source 31A is shown about different L / D and different observation angle (theta).

61A to 61C are diagrams showing the intensity distribution based on the result of simulation 3 in Example 14. FIG. FIG. 61 (a) shows the intensity distribution with respect to the position and the observation angle θ with reference to the light source 31A when L / D = 2.0. FIG. 61 (b) shows the intensity distribution with respect to the position and the observation angle θ based on the light source 31A when L / D = 2.5. FIG. 61 (c) shows the intensity distribution with respect to the position and the observation angle θ with respect to the light source 31A when L / D = 3.0.

In Example 14, the cross-sectional shape of the convex part 41 is designed so that a desired intensity distribution can be obtained for L = 30 mm and D = 13.87, that is, about L / D of about 2.17. And from Table 13 and FIG. 61 (b), when L / D is 2.17 which is close to the design value, strength uniformity (brightness uniformity) (%) close to 100% can be secured in the front direction. In addition, from the results shown in Table 13 and Figs. 61 (a) to 61 (c), even if L / D is out of the design value, the change in the intensity uniformity (brightness leveling agent) is relatively gentle (for example, comparative example). The luminance nonuniformity can be reduced more stably. Furthermore, even when the observation angle θ is 20 ° and 30 °, it is possible to secure a high intensity uniformity (brightness leveling system) and to show that the change in the intensity leveling system (luminance leveling system) is smooth with respect to the change in L / D. Can be.

(Result of Example 15)

62 shows the results of simulation 1 in Example 15. FIG. In FIG. 62, the intensity distribution of the front direction with respect to the light from the light source 31A when D = 12 (mm) is shown. 62 represents the position with respect to the light source 31A in the X-axis direction, and the vertical axis represents the intensity (arbitrary unit). FIG. 63 is a diagram showing the results of simulation 2 in Example 15. FIG. 63 represents the position with respect to the light source 31A in the X-axis direction, and the vertical axis represents the standardized intensity normalized to the maximum intensity.

As shown to FIG. 62 and FIG. 63, in the cross-sectional shape of the convex part 41 of Example 15, it turns out that it has the linear change area | region 51 from the top part to the foot part of intensity | strength distribution. In addition, from FIG. 63, in Example 15, the intensity distribution under the conditions of simulation 2 also satisfies conditions (c) and (d) together with conditions (a) and (b). In addition, w ₄ can be said that satisfies w _1/6 or more in the condition (c).

Table 14 shows an example of the results of simulation 3. In Table 14, the result of calculating the intensity | strength uniformity (brightness uniformity) (%) based on the intensity with respect to the position from the light source 31A is shown with respect to L / D and observation angle (theta).

64A to 64C are diagrams showing the intensity distribution based on the result of simulation 3 in Example 15. FIG. FIG. 64 (a) shows the intensity distribution with respect to the position and the observation angle θ based on the light source 31A when L / D = 2.0. FIG. 64 (b) shows the intensity distribution with respect to the position and the observation angle θ based on the light source 31A when L / D = 2.5. FIG. 64C shows the intensity distribution with respect to the position and the observation angle θ based on the light source 31A when L / D = 3.0.

In Example 15, the cross-sectional shape of the convex part 41 is designed so that desired intensity distribution may be obtained with respect to L = 30mm and D = 12, that is, L / D2.5. And from Table 14 and FIG. 64 (b), when L / D is 2.5 as a design value, the intensity | strength uniformity (brightness leveling agent) (%) near 100% can be ensured in the front direction. In addition, from the results shown in Table 14 and Figs. 64 (a) to 64 (c), even if L / D is out of the design value, since the change in intensity uniformity (luminance uniformity) is gentle, the luminance nonuniformity is reduced more stably. It can be seen that. Furthermore, even when the observation angle θ is 20 ° and 30 °, it is possible to secure a high intensity uniformity (brightness leveling system) and to show that the change in the intensity leveling system (luminance leveling system) is smooth with respect to the change in L / D. Can be.

(Result of Example 16)

65 shows the results of simulation 1 in Example 16. FIG. In FIG. 65, the intensity distribution of the front direction with respect to the light from the light source 31A when D = 9.375 (mm) is shown. 65, the horizontal axis has shown the position with respect to the light source 31A in the X-axis direction, and the vertical axis has shown intensity (arbitrary unit). 66 is a diagram showing the results of simulation 2 in Example 16. FIG. 66 represents the position with respect to the light source 31A in the X-axis direction, and the vertical axis represents the normalized intensity normalized to the maximum intensity.

As shown in FIG. 65 and FIG. 66, in the cross-sectional shape of the convex part 41 of Example 16, it turns out that it has a linear change area 51 in the intensity reduction area | region of intensity distribution. 66, in the sixteenth embodiment, the intensity distribution under the condition of simulation 2 also satisfies the condition (c) together with the conditions (a) and (b). In addition, w ₄ can be said that satisfies w _1/8 or more in the condition (c).

Table 15 shows an example of the results of simulation 3. In Table 15, the result of having calculated the intensity uniformity (brightness uniformity) (%) based on the intensity with respect to the position from the light source 31A is shown about L / D and observation angle (theta).

67A to 67C are diagrams showing the intensity distribution based on the result of simulation 3 in Example 16. FIG. FIG. 67 (a) shows the intensity distribution with respect to the position and the observation angle θ with reference to the light source 31A when L / D = 3.0. FIG. 67 (b) shows the intensity distribution with respect to the position and the observation angle θ with respect to the light source 31A when L / D = 3.2. FIG. 67 (c) shows the intensity distribution with respect to the position and the observation angle θ with reference to the light source 31A when L / D = 3.5.

In Example 16, the cross-sectional shape of the convex part 41 is designed so that desired intensity distribution may be obtained with respect to L = 30mm and D = 9.375, that is, L / D 3.2. In addition, from Table 15 and FIG. 67 (b), when L / D is a design value of 3.2, strength uniformity (brightness leveling agent) (%) close to 100% in the front direction can be ensured. Further, from the results shown in Table 15 and Figs. 67 (a) to 67 (c), even if L / D is out of the design value, the variation in intensity uniformity (luminance uniformity) is gentle, so that the luminance nonuniformity is more stably reduced. You can do it. Furthermore, even when the observation angle θ is 20 ° and 30 °, it is possible to secure a high intensity uniformity (brightness leveling system) and to show that the change in the intensity leveling system (luminance leveling system) is smooth with respect to the change in L / D. Can be.

(Result of Example 17)

FIG. 68 is a diagram showing the results of simulation 1 in Example 17. FIG. In FIG. 68, the intensity distribution of the front direction with respect to the light from the light source 31A when D = 8.0 (mm) is shown. 68, the horizontal axis has shown the position with respect to the light source 31A in the X-axis direction, and the vertical axis has shown intensity (arbitrary unit). 69 is a diagram showing the results of simulation 2 in Example 17. FIG. 69 represents the position with respect to the light source 31A in the X-axis direction, and the vertical axis represents the normalized intensity normalized to the maximum intensity.

As shown in FIG. 68 and FIG. 69, in the cross-sectional shape of the convex part 41 of Example 17, it turns out that it has the linear change area 51 in the intensity reduction area | region of intensity distribution. 69, in the seventeenth embodiment, the intensity distribution under the condition of simulation 2 also satisfies the condition (c) together with the conditions (a) and (b). In addition, w ₄ can be said that satisfies w _1/10 or more in the condition (c).

Table 16 shows an example of the results of simulation 3. In Table 16, the result of having calculated the intensity uniformity (brightness uniformity) (%) based on the intensity with respect to the position from the light source 31A is shown about L / D and observation angle (theta).

70A to 70C are diagrams showing the intensity distribution based on the result of simulation 3 in Example 17. FIG. FIG. 70 (a) shows the intensity distribution with respect to the position and the observation angle θ with respect to the light source 31A when L / D = 3.5. FIG. 70 (b) shows the intensity distribution with respect to the position and the observation angle θ based on the light source 31A when L / D = 3.75. FIG. 70 (c) shows the intensity distribution with respect to the position and the observation angle θ with respect to the light source 31A when L / D = 4.0.

In Example 17, the cross-sectional shape of the convex part 41 is designed so that desired intensity distribution may be obtained for L = 30 mm and D = 8.0, that is, L / D = 3.75. And, from Table 16 and FIG. 70 (b), when L / D is 3.75, which is a design value, strength uniformity (brightness leveling agent) (%) close to 100% in the front direction can be secured. In addition, from the results shown in Table 16 and Figs. 70 (a) to 70 (c), even if L / D is out of the design value, since the change in intensity uniformity (luminance uniformity) is gentle, the luminance nonuniformity is reduced more stably. You can do it. Furthermore, even when the observation angle θ is 20 ° and 30 °, it is possible to secure a high intensity uniformity (brightness leveling system) and to show that the variation of the intensity leveling system (luminance leveling system) is smooth with respect to the change in L / D. Can be.

(Comparison of the results of Examples 14 to 17 and Comparative Example 2)

In Comparative Example 2, as shown in the results of simulations 1 and 2, the intensity distribution for one light source 31A does not have a linear change region 51. In contrast, in Examples 14 to 17, as shown in the results of the simulations 1 and 2, the intensity distribution of one light source 31A includes the linear change region 51. Further, as can be understood from the comparison of the results of simulations 1 and 2 in each of Examples 14 to 17 and Comparative Example 2, the intensity distribution even if the distance between the light source 31A and the light diffusion plate 40 changes. Has the same characteristics. Therefore, when the intensity distribution measured by arranging the light source 31 at a position 100 mm away from the light diffusion plate 40 satisfies a predetermined condition (for example, conditions (a) and (b)), the light diffusion plate ( The intensity distribution with respect to one light source 31A arranged at a predetermined distance D with respect to 40 also satisfies the same condition. Accordingly, it can be seen that the shape of the convex portion 41A may be inspected by arranging the light source 31A 100 mm away from the light diffusion plate 40.

In addition, the cross-sectional shape of the convex part 41 used in Examples 14-17 is designed by making distance D into a predetermined value. This is designed to obtain a desired intensity distribution for a given L / D. And from the result of simulation 3, in each Example 14-17, the high luminance uniformity can be implement | achieved with respect to the predetermined L / D used for design.

Further, in Examples 14 to 17 having the linear change region 51, the change in luminance uniformity with respect to the change in L / D can be made smaller than in the comparative example without the linear change region 51. Therefore, in the case of Examples 14-17, even if it deviates from the predetermined L / D set for design, the fall of a brightness | luminance uniformity can be reduced. As a result, luminance unevenness can be suppressed more stably, and as a result, the light diffusing plates 40 of Examples 14 to 17 have versatility.

In addition, from the comparison of the results of Examples 14 to 17, when designed using the intensity distribution having the linear change region 51, even if the L / D is increased, that is, the surface light source device 20 or the transmissive image display Even if the device 1 is thinned, it can be seen that a high luminance uniformity can be ensured. Also in this case, even if L / D is changed, the reduction of the brightness uniformity can be suppressed as described above.

According to the embodiments and examples described above, it is possible to provide a light control panel capable of more stably suppressing luminance unevenness, and a surface light source device and a transmissive image display device including the light control plate.

As mentioned above, although embodiment and Example of this invention were described, this invention is not limited to the said embodiment and Example. For example, although the light control plate was described as the light diffusion plate 40, the present invention is not limited to this, and the luminance uniformity in the plane parallel to the plane on which the plurality of light sources are arranged is adjusted. It may be an optical component. For example, a light control plate can also be set as the brightness adjusting plate called optical sheets or optical films, such as a prism sheet and a lens sheet, which have two or more convex-shaped parts on the light output side of the board which consists of transparent materials.

In addition, in the above description, although the some light source 31 which the light source part 30 has is arrange | positioned at substantially equal intervals at the space | interval L, the distance between two adjacent light sources 31 and 31 is different. Also good. In this case, the distance between the light sources 31 and the distance between the light source 31 and the light control panel 40 using the average distance L _m of the interval between two adjacent light sources 31 and 31. The ratio of can be defined. On the other hand, when the distance between two adjacent light sources 31 and 31 is different, L / D differs according to a position. In the light diffusion plate 40, as described above, even if L / D is changed, the contribution to the intensity distribution by the light from the plurality of light sources 31 can be reduced. Therefore, even when the distance between two adjacent light sources 31 and 31 is different, the necessity of changing the cross-sectional shape of the convex portion 41 according to the position is reduced. Therefore, the light diffusing plate 40 can be easily designed and manufactured, and the manufacturing cost of the light diffusing plate 40, the surface light source device 20, and the transmissive image display device 1 can be reduced.

Furthermore, although the cross-sectional shape of the convex part 41 was the same, it does not necessarily need to be the same. However, as mentioned above, manufacturing cost can be reduced by being the same.

In addition, in 2nd Embodiment, although the optical element part was demonstrated as the convex part 41, if an optical element part is a shape which can implement intensity distribution shown in FIG. 5, it will not specifically limit.

Claims (11)

A light control panel capable of emitting light incident from a first surface from a second surface located on the side opposite to the first surface,
A plurality of convex portions extending in a first direction and arranged in parallel in a second direction orthogonal to the first direction are formed on the second surface,
In the cross section orthogonal to the first direction of the convex portion, the axis passing through both ends with respect to the second direction of the convex portion is assumed to be the x axis, and is orthogonal to the x axis passing through the center of the both ends on the x axis. When the axis is set to the z-axis and the length of the convex portion in the x-axis direction is w _a ,
The contour shape of the convex portion in the cross section is represented by z (x) that satisfies Equation 1 in the range of -0.475w _a ≤x≤0.475w _a ,
Light control panel.
[Equation 1]

In formula (1), however, z _B (x) = z ₀ (x) x r (r is a constant of 0.95 or more and 1.05 or less), and z ₀ (x) is represented by formula (2).
[Equation 2]

(Mathematical formula 2, h _a is a constant less than 0.27w _a more than 1.02w _a, k is _a constant of 0.00 or less than -0.38) The method of claim 1,
An optical control panel wherein the convex portions have a refractive index of 1.48 or more and 1.62 or less. The method of claim 1,
The refractive index of the said convex part is 1.48 or more and less than 1.50,
And wherein h _a is _a more than 0.34w 1.02w _a or less,
Wherein k _a is more than -0.38 -0.06 or less, the light control panel. The method of claim 1,
The refractive index of the said convex part is 1.50 or more and less than 1.52,
And wherein h _a is _a more than 0.33w 0.99w _a or less,
Wherein k _a is more than -0.35 -0.06 or less, the light control panel. The method of claim 1,
The refractive index of the said convex part is 1.52 or more and less than 1.54,
And wherein h _a is _a more than 0.31w 0.98w _a or less,
Wherein k _a is more than -0.33 -0.05 or less, the light control panel. The method of claim 1,
The refractive index of the said convex part is 1.54 or more and less than 1.56,
And wherein h _a is _a more than 0.30w 0.96w _a or less,
Wherein k _a is more than -0.30 -0.05 or less, the light control panel. The method of claim 1,
The refractive index of the said convex part is 1.56 or more and less than 1.58,
And wherein h _a is _a more than 0.29w 0.94w _a or less,
Wherein k _a is more than -0.29 -0.03 or less, the light control panel. The method of claim 1,
The refractive index of the said convex part is 1.58 or more and less than 1.60,
And wherein h _a is _a more than 0.28w 0.92w _a or less,
The said k _a is -0.27 or more and -0.02 or less, The optical control board. The method of claim 1,
The refractive index of the said convex part is 1.60 or more and 1.62 or less,
And wherein h _a is _a more than 0.27w 0.87w _a or less,
The said k _a is -0.27 or more and 0.00 or less, The optical control board. The optical control plate of any one of Claims 1-9,
A plurality of light sources arranged to be spaced apart from each other and supplying light to the first surface of the light control plate,
Surface light source device. The optical control plate of any one of Claims 1-9,
A plurality of light sources arranged to be spaced apart from each other and supplying light to the first surface of the light control plate;
And a transmissive image display unit which is output by a plurality of light sources and is illuminated by light passing through the light control plate to display an image.
Transmissive image display device.

Images