JP2000330112A - Illumination device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a small-sized illuminating device which does not produce bright lines or dark regions but emits uniform illumination light by disposing an incident angle controlling means between a light source and a light transmission body and aligning the propagation direction of light from the light source to enter the light guiding body. SOLUTION: The illuminating device 100 is equipped with a light source 101, a light guiding body 102, an incident angle controlling means 103 disposed between the light source 101 and the light guiding body 102, and an antireflection film 104 laminated on the exiting face 102b of the light guiding body 102. The incident angle controlling means 103 has a plurality of prisms and is formed on the entering face 102a of the light guiding body 102. The prisms are formed in such a manner that the side line (a) makes 90 deg. angle with the entering face 102a of the light guiding body 102 and that the side line (b) makes 65 deg. angle with the recesses or projections 102d, and the apex between the side line (a) and the side line (b) is 39 deg.. The propagation direction of the light from the point light source 101 is controlled to be almost perpendicular to the extending direction of stripe recesses or projections by the plurality of prisms as the incident angle controlling means 103, and the light is made to enter the light guiding body 102. Thus, uniform illumination without bright lines or dark regions can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device comprising a liquid crystal display element used for an information display system or OA equipment and a lighting device thereof, and in particular, without deteriorating the display quality of the liquid crystal display element. The present invention relates to a lighting device for efficiently lighting.

[0002]

2. Description of the Related Art Liquid crystal display elements are roughly classified into a transmission type in which an image is displayed by controlling the amount of transmitted light emitted from the outside and a reflection type in which an image is displayed by controlling the amount of reflected light. For example, in a transmissive liquid crystal display device, an illumination device generally called a backlight is arranged on the back surface and used. On the other hand, in the reflection type liquid crystal display element, while the display can be performed using ambient light, the degree to which the display luminance depends on the surrounding environment is very high, and the display cannot be recognized at all especially in darkness such as at night. Sometimes. Therefore, an illuminating device called a front light for illuminating the reflective liquid crystal display element from the front is required in case sufficient ambient light cannot be obtained.

An example of the configuration and operation of a reflection type liquid crystal display device will be described with reference to FIG. FIG. 9 is a diagram illustrating an example of a reflective liquid crystal display device.

One polarizing plate and a λ / 4 plate are provided in front of the liquid crystal layer,
A reflective electrode is arranged on the back. The transmission axis of the polarizing plate or the absorption axis and the slow axis or the fast axis of the λ / 4 plate are arranged at an angle of 45 °, and the linearly polarized light transmitted through the polarizing plate out of the illumination light is λ / 4. The light is converted into circularly polarized light by the plate and enters the liquid crystal layer. Here, when the liquid crystal layer does not modulate the circularly polarized light, the direction of rotation of the circularly polarized light is reversed when reflected by the reflective electrode, and after passing through the λ / 4 plate again, the linearly polarized light is orthogonal to the transmission axis of the polarizing plate. Is absorbed and black is displayed. When the liquid crystal layer is modulated so that the incident circularly polarized light is reflected while preserving it, the light is transmitted through a λ / 4 plate, then emitted as linearly polarized light coincident with the transmission axis of the polarizing plate, and white is displayed.

[0005] Characters and images are displayed by controlling the modulation by the liquid crystal layer for each pixel as described above, and the red (R), green (G), and blue (B) arranged in each pixel are displayed. Color display can be performed by transmitting and coloring the primary color filter. There are various arrangement patterns of R, G, and B pixels. Representative examples include a delta arrangement shown in FIG. 10A and a stripe arrangement shown in FIG. 10B. The direction is repeated in the vertical direction.

The number of pixels and the size of the pixels are also various. In the case of a reflection type liquid crystal display device of a 2.0 type delta arrangement, the number of horizontal pixels × the number of vertical pixels is 280 × 220, and the pixel size is 1. The horizontal direction is 145.5 μm, the vertical direction is 138.5 μm, and 2.
In the case of the reflection type liquid crystal display element of the 5-type delta arrangement, the number of pixels is 280 × 220 and the pixel size is 17
The specification of 9.5 × 168.5 μm is adopted.

In a stripe arrangement, for example, in the case of a reflection type liquid crystal display device of 3.8 QVGA, the number of pixels is 960 × 240 and the pixel size is 81 ×
The specification of 234.5 μm is adopted.

[0008] By the way, many lighting devices have been conventionally proposed. An example will be described with reference to FIGS.

FIG. 11 shows SID'95Digestp.
FIG. 375 is a diagram showing a front light disclosed in 375. Specifically, FIG. 11A is a view of the front light as viewed from above, and FIG. 11B is a view of the front light shown in FIG. 11A as viewed from the side. .

The front light shown in FIG.
A light guide 12 having a linear light source 11, an incident surface 12a on which light from the linear light source 11 is incident, an emission surface 12b for emitting illumination light, and a facing surface 12c facing the emission surface 12b.
And

The opposing surface 12c of the light guide 12 is periodically formed with streaky irregularities 12d.
Is a light guide 12 from a linear light source 11 via an incident surface 12a.
Propagation section 12e for totally reflecting and propagating light incident inside
And a reflector 12f that reflects toward the emission surface.
Therefore, in this front light, the light from the linear light source 11 is directly or the light exit surface 12b and the unevenness 12d.
Is totally reflected by the propagating portion 12e and propagates inside the light guide 12 to reach the reflecting portion 12f of the irregularities 12d, and the light exit surface 12b
And the light guide 12 emits illumination light.

FIG. 12 is a diagram showing a front light disclosed in Japanese Patent Application Laid-Open No. H11-14986. Specifically, FIG. 12A is a diagram of the front light as viewed from above, and FIG. 12B is a diagram of the front light of FIG. 12A as viewed from the side. .

The front light shown in FIG.
A point light source 21 and a light guide 22 having an incident surface 22a on which light from the point light source 21 is incident, an emission surface 22b for emitting illumination light, and a facing surface 22c facing the emission surface 22b are provided. . On the opposing surface 22c of the light guide 22, circular irregularities 22d are formed in a dot shape, and the incident surface 22a is formed.
The light incident on the inside of the light guide 22 through is reflected by the circular irregularities 22d and exits the exit surface 22b. As the point light source 21, an LED, a tungsten lamp, or the like can be applied. However, the front light is suitable for a lighting device of a reflection type liquid crystal display element in a portable information terminal or the like because it can be lit by direct current and has low power consumption. ing.

FIG. 13 is a diagram showing a front light disclosed in Japanese Patent Application Laid-Open No. 10-260404. In the front light shown in FIG. 13, a point light source is used. As shown in FIG. 13, the point light source 31 and the light guide 32
And a lens is arranged between them. That is, the point light source 3
A lens having a curved surface is formed on the incident surface 32a of the light guide 32 corresponding to 1. Therefore, the divergence state of the light traveling inside the light guide 32 is adjusted, and the effective illumination area can be uniformly illuminated.

FIG. 14 is a diagram showing a lighting device disclosed in Japanese Patent Application Laid-Open No. 10-260405. The illumination device shown in FIG. 14 converts the light from the point light source 41 into a linear shape by a linear light guide 43 disposed between the point light source 41 and the light Make it incident. Therefore, in the illumination device shown in FIG. 14, the illumination light of the light guide 42 can be made uniform over the entire area.

[0016]

However, the above-mentioned conventional lighting device has the following problems.

As described above, SID'95Digests
tp. 375, the light guide 1 via the incident surface 12a from the linear light source 11
The light incident on the inside of the light source 2 propagates while repeating total reflection, reaches the reflection part 12f of the unevenness 12d, and emits the light from the emission surface 12b.
The illumination light is reflected toward the light source and emits the illumination light.
A light beam that travels perpendicularly to the streaky irregularities 12d formed in 2c is reflected most efficiently by the reflecting portion 12f of the irregularities 12d, and the emission angle is small, and effective illumination light can be obtained.

Therefore, unless the length of the effective light-emitting area of the linear light source 11 is longer than the longitudinal direction of the incident surface 12a of the light guide 12, uniform illumination cannot be obtained. This is because when the length of the effective light emitting area of the linear light source 11 is shorter than the incident surface 12a of the light guide 12, the light that travels perpendicular to the streaky irregularities 12d from where the light emitting portion does not exist. This is because effective illumination light cannot be obtained because of the absence of, and it becomes a dark area.

Here, a typical cold cathode tube as a linear light source is SID'95 Digestp. When applied to the front light disclosed in U.S. Pat. No. 375, the non-light-emitting area due to the progress of the blackening of the fluorescent material and the electrode portion exists in the entire length of the cold cathode tube of about 20 mm. I have to make it about 20mm longer than the light guide,
This causes an increase in the size of a lighting device and a display device equipped with the lighting device.

The front light disclosed in Japanese Patent Application Laid-Open No. H11-14986 discloses circular irregularities.
2d generates reflected light irrespective of the traveling direction of light, and uniform illumination is possible in a region where light from the point light source travels inside the light guide, but illumination light is not emitted in other regions. It becomes a dark area.

Further, as shown in FIG. 12C, when a point light source is used for a light guide having streaky irregularities, as described above, the light is orthogonal to the streaky irregularities. Since the traveling light beam is most efficiently used for the illumination light, a very bright bright line is generated from the point light source in a direction orthogonal to the streaky irregularities. Furthermore, there is no incident light into the light guide from where the point light source is not arranged, and no illumination light is generated, resulting in a dark area. Therefore, when the lighting device shown in FIG. 12C is used for a liquid crystal display element,
The display quality is significantly degraded by uneven illumination.

Even when a lens is arranged between a point light source and a light guide as in the configuration disclosed in JP-A-10-260404, the spread of light from the point light source is increased, and Illuminating light is emitted, but a bright line that travels perpendicularly to the streaky irregularities from the point light source is not prevented.

On the other hand, when a linear light guide is arranged between a point light source and a light guide as in the illumination device disclosed in Japanese Patent Application Laid-Open No. 10-2604056, the point light source is Since the light is converted into a linear light source by the light guide and then incident on the light guide, even when this is applied to a light guide having streak-like irregularities, the above-mentioned uniform illumination that does not generate the bright line can be obtained. It becomes possible. However, of the light emitted from the linear light guide and incident on the light guide, the light that is effectively used as illumination light is a light beam that is substantially orthogonal to the streaky irregularities formed in the light guide, The efficiency of using light from a point light source is very low, and bright illumination is difficult. In addition, since the point light source is arranged at the longitudinal end of the linear light guide, increasing the number of the point light sources to obtain bright illumination is difficult to obtain in the place of the arrangement or the linear light guide. This leads to an increase in size. Furthermore, since the effective light-emitting area of the linear light guide needs to be longer than the light incident surface of the light guide, the place where the point light source is disposed protrudes from the light incident surface of the light guide, and the lighting device However, there is a problem that the size becomes large.

[0024] In view of the above problems, the present invention provides a point light source,
Alternatively, in a lighting device including a linear light source and a light guide, it is possible to provide a bright and uniform lighting, and to provide a small-sized lighting device suitable for a liquid crystal display element.

[0025]

One of the features of the illumination device of the present invention is that a light source, incident angle control means for receiving light emitted from the light source, and light emitted from the incident angle control means. An incident surface for incidence, and a light guide having an emission surface that is substantially perpendicular to the incident surface and emits illumination light, the incident angle control unit is disposed between the light source and the light guide,
The incident angle control means controls a traveling direction of the light emitted from the light source, and aligns an angle between the light emitted from the incident angle control means and the incident surface of the light guide. Objective is achieved.

A plurality of stripe-shaped concave or convex portions are formed on the light emitting surface of the light guide or on a surface facing the light emitting surface, and the concave or convex portions are incident from the light incident surface. The light propagating in the light guide is refracted and reflected, and the illumination light is emitted from the emission surface, and the direction in which the concave or convex portion extends is substantially orthogonal to the light emitted from the incident angle control means. Is also good.

[0027] The concave or convex portion is formed on the opposing surface of the light guide, and the concave or convex portion is a light that enters the light guide through the incident surface of the light guide. And a reflector that substantially reflects the light toward the emission surface of the light guide.

The light source may be a point light source.

The point light source may be arranged so that the main direction of the light emitted from the point light source is not orthogonal to the incident surface of the light guide.

[0030] The direction of the light emitted from the point light source may be substantially parallel to the incident surface of the light guide.

[0031] A reflection sheet may be arranged near the point light source, and the reflection sheet may be inclined toward an incident surface of the light guide.

The incident angle control means has a plurality of prisms, and a linear light guide is arranged in a light emitting direction of the point light source;
The linear light guide may convert light from a point light source into a linear light, and emit the light toward the plurality of prisms.

The light source is a linear light source, the length of the effective issuance area of the linear light source is shorter than the longitudinal direction of the incident surface of the light guide, and the incident angle control means is a linear light source. The traveling direction of the light from the light source may be controlled so that light having a uniform incident angle is incident on the entire incident surface of the light guide.

[0034] The incident angle control means is a plurality of prisms, and the incident angle control means refracts and reflects the light emitted from the light source, aligns the traveling direction of the light, and adjusts the light traveling direction. May be incident.

[0035] The plurality of prisms may be formed on the incident surface of the light guide.

The plurality of prisms are arranged toward the light source side, and an angle α between at least one side of the prism and streaky irregularities formed on the light guide is defined by a condition 40.
° ≦ α <90 ° may be satisfied.

The vertex angle β of the prism is 0 ° <β <
80 ° may be satisfied.

The incident angle control means is a hologram,
The traveling direction of the light from the light source may be controlled to make the incident angles of the light guide with respect to the incident surface uniform.

[0039] The display device may include the illumination device and a liquid crystal display element.

The operation will be described below.

In the illumination device having the above-described structure, the traveling direction of the light emitted from the light source is controlled by the incident angle control means.
Since the light enters the light incident surface of the light guide at a predetermined incident angle,
Illumination light exiting the exit surface can be made uniform. In particular, when streak-like irregularities are formed in the light guide, the incident angle control means aligns the traveling direction of the light from the light source in a direction substantially orthogonal to the streak-like irregularities, so that the bright line or the dark region can be formed. No, uniform illumination can be realized.

The streaky irregularities are formed on the opposing surface of the light guide, and a propagation portion for propagating light that has entered the inside of the light guide mainly through the incident surface, and mainly reflects the light toward the exit surface. It may be constituted by a reflection part. According to the light guide of the above configuration, light that has entered the inside from the light source via the incident surface of the light guide undergoes total reflection at the emission surface of the light guide, and at the propagation portion of the unevenness formed on the opposing surface. The light repeatedly propagates and reaches the uneven reflection portion, and is totally reflected toward the emission surface and emitted. Therefore, it is possible to realize a lighting device with high light use efficiency using total reflection. In addition, the light guide as described above is formed of a transparent resin represented by an acrylic resin, a polycarbonate resin, an epoxy resin, or a method of forming irregularities on a transparent substrate, and the irregularities are formed on the transparent substrate. It can be manufactured by a method such as laminating sheets.

The light source may be a point light source, and the incident angle control means may control a traveling direction of the light from the point light source so that light having a uniform incident angle is incident on an incident surface of the light guide. . In the illumination device having the above-described configuration using the point light source, the traveling direction of the light from the point light source is controlled by the incident angle control means, and the light is guided in a direction substantially perpendicular to the streaky irregularities formed on the light guide. Since the light is incident on the light body, uniform illumination can be achieved without generating a bright line from the point light source as described above. Also, there is no limitation on the position of the point light source as in the combination of the point light source and the linear light guide, and a plurality of point light sources can be arranged near the incident surface of the light guide, so that the size of the lighting device is increased. Bright illumination can be realized without inducing.

Further, as shown in FIGS. 15B and 15C, the point light sources are arranged such that the main direction of light emission is not orthogonal to the incident surface of the light guide. Is also good. On the other hand, FIG. 15A is a diagram illustrating an illuminating device in which a point light source is arranged such that a main direction of light emission is orthogonal to an incident surface of a light guide. In this case, FIG.
Light and dark stripes are formed as shown in the figure.

If a point light source is arranged as shown in FIGS. 15 (b) and 15 (c), the main direction of light emission is directed to the incident surface of the light guide as shown in FIG. 15 (a). Compared to a case where a point light source is arranged so as to be orthogonal to the light source, the length of light projected from the point light source is longer, and a wider area can be uniformly illuminated by one point light source. .

The arrangement of the point light sources shown in FIG. 15C is more preferable than the arrangement of the point light sources as shown in FIG. Since the point light source is arranged so that the main direction of light emission is substantially parallel to the incident surface of the light guide, one point light source can uniformly illuminate the widest range. It is.

In the light emitting direction of the point light source, a reflecting means inclined toward the incident surface of the light guide is arranged, and a linear light guide is arranged in the light emitting direction of the point light source. In the light body, light from a point light source may be converted into a linear light and emitted toward the incident angle control means. Light from the point light source arranged so that the main direction of light emission is substantially parallel to the incident surface of the light guide efficiently enters the incident angle control means, and is guided in a state where the traveling directions are aligned. Light is incident on the light body. Therefore, even a small point light source can uniformly and brightly illuminate a wide range.

[0048] An illumination device, wherein the light source is a linear light source,
The length of the effective light emitting area of the linear light source is shorter than the longitudinal direction of the incident surface of the light guide, and the incident angle control means controls the traveling direction of the light from the linear light source to cover the entire incident angle of the light guide. May be made to enter light with a uniform incident angle. As described above, in a light guide having streak-like irregularities, of light that has entered the interior through the light-incident surface of the light guide, a light beam that is substantially orthogonal to the streak-like irregularities is most efficiently used as illumination light. Because it is used, if the length of the effective light emitting area of the linear light source is shorter than the incident surface of the light guide,
Since there is no light beam that travels perpendicularly to the streaky unevenness from where the light emitting portion does not exist, a dark region is generated. However, in the illumination device having the above-described configuration, the incident angle control means controls the traveling direction of light that has reached the entire incident surface of the light guide from the effective light emitting area of the linear light source, and the streaks formed on the light guide are formed. The light is incident on the light guide in a direction substantially perpendicular to the unevenness of the light guide. Therefore, light substantially perpendicular to the streaky irregularities enters from a position corresponding to the non-light emitting region of the linear light source on the incident surface of the light guide, and uniform illumination without dark regions can be realized. The portion where the linear light source protrudes from the light body is reduced, and the size of the illumination device can be reduced.

The incident angle control means may comprise a plurality of prisms, and the light from the light source may be refracted and reflected so that the light travels in the same direction and is incident on the light guide. Further, the plurality of prisms may be formed on an incident surface of the light guide. According to the above configuration, the traveling direction can be made uniform by refracting and reflecting light from the light source by the plurality of prisms arranged between the linear light source or the point light source and the light guide.

FIG. 16A shows the shape and operation of the prism.
This will be described with reference to FIG.

The prism is arranged toward the light source side, and the angle α between at least one side of the prism and the streaky irregularities formed on the light guide is defined as “40 ° ≦ α <9.
0 ° ”is preferably satisfied. It is preferable that the vertex angle β of the prism satisfies the condition “0 ° <β ≦ 80 °”.

The two sides of the prism are referred to as sides a and b for convenience. Here, in general, the material of the prism or the light guide in which the prism is integrally formed on the incident surface is a transparent resin represented by an acrylic resin, a polycarbonate resin, an epoxy resin, or the like, and its refractive index is 1.5-1.
Therefore, the critical angle at which total reflection occurs at the interface between the prism and air is about 40 °. Therefore, the light emitted from the light source and incident on the side a is refracted to have an incident angle of 40 ° to 9 °.
When the light reaches the side b at 0 °, it is reflected at a reflection angle of 40 ° to 90 ° and enters the light guide. In other words, the light traveling from the light source can be incident on the incident surface of the light guide with the traveling plane being aligned within 50 °.

Further, if the angle α formed between the side b and the streaky irregularities formed on the light guide satisfies the condition “40 ° ≦ α <90 °”, the light totally reflected on the side b will be streaky. The light can be substantially orthogonal to the irregularities, and is effectively used as illumination light by the light guide.

In particular, when the angle α is 65 °, as shown in FIG. 16B, the light totally reflected on the side b enters within 25 ° with respect to the orthogonal line of the streak-like unevenness. Angle α
Is preferably about 65 °. That is, the prism is α = 6
Very preferably, it is a 5 ° isosceles triangle.

In addition, in order for light refracted on the side a within a refraction angle of 40 ° and reaching the side b at an incident angle of 40 ° or more, the apex angle of the prism formed by the two must be within 80 °. is there. After satisfying this condition, if both the sides a and b form the streaky unevenness and the angle α satisfies the condition “40 ° ≦ α <90 °”, as shown in FIG. From there, light substantially orthogonal to the streaky irregularities enters.

In the illumination device, the incident angle control means may be a hologram, and the light from the light source may be diffracted and incident on the incident surface of the light guide in a uniform traveling direction.

First, the hologram which is the incident angle control means in the illumination device having the above-described configuration will be described based on "Holographic Display" (edited by Junpei Tsubouchi, published by Sangyo Tosho Co., Ltd.). The following is a summary of the principles of holography described in the first volume and section 3.6 of this document.

FIG. 17 shows a typical optical system for recording a point object as a hologram. That is, a laser is used as a light source, and a laser beam emitted from the laser is split into two beams by a half mirror. Then, a lens is put in each beam, one is a parallel light (plane wave), and the other is an object light (spherical wave) from a point object, so that these two light waves intersect and interfere in a certain space I do. Next, the light intensity distribution of the interference fringes is recorded on a photographic film. Here, since the pitch of the interference fringes is very fine, a high-resolution special photographic film is required to faithfully record the pitch.

When the light wavefront is reproduced from the photographic film, that is, the hologram, the hologram is irradiated with parallel light incident upon recording of the hologram. Then, as shown in FIG. 18A, the parallel light is diffracted and emitted in a direction corresponding to the direction of the interference fringes recorded on the hologram.
Then, this diffracted wave forms one light wavefront, which coincides with the object light which is the other light incident upon recording the hologram. Therefore, the parallel light applied to the hologram is converted into light from one point away from the hologram.

Further, as shown in FIG. 18B, when the light is irradiated on the light wavefront which travels in the opposite direction to the parallel light at the time of recording the hologram, diffracted light condensed at one point is generated.

The hologram, which is the incident angle control means, is produced, for example, in the same manner as described above, and irradiates the object light incident upon recording of the hologram by replacing it with light from a point-like light source. As shown in (1), diffracted light beams having parallel and uniform traveling directions are generated. Alternatively, as shown in FIG. 19, by exposing a hologram to interference fringes of two parallel lights, light from a linear light source can be diffracted, and light with a uniform traveling direction can be emitted.

The illumination device described above can emit bright and uniform illumination light suitable for a liquid crystal display element.
Here, when streaks and projections are periodically formed in the light guide of the lighting device, when combined with a liquid crystal display element, the periodic streak and projections and the periodic pixel pattern of the liquid crystal display element interfere with each other. As a result, bright and dark fringes called moiré fringes are generated, and the display quality of the liquid crystal display element is significantly deteriorated. However, by giving an optimum angle between the direction in which the streaky irregularities are formed and the direction in which the pixel pattern is repeated, the cycle of the moire fringes is shortened, and a phenomenon occurs in which the moire fringes are not visually recognized.

When a light guide is arranged on a reflection type liquid crystal display element having a delta arrangement of 2.0 type and 2.5 type, the angle between the direction of the periodic uneven streaks and the horizontal direction of the pixel pattern is set. The result of observing moiré fringes by applying the same and finding an angle range where moiré fringes are not recognized is shown in FIG. 20A. FIG. 20A shows that although the angular range varies depending on the period of the streaky irregularities, moiré fringes are not observed in the angle ranges of approximately 10 ° to 25 ° and 55 ° to 80 °.

Similarly, FIG. 20B shows the result of finding an angle range in which moire fringes are not recognized in the reflection type liquid crystal display device having 3.8-type QVGA and stripe arrangement. FIG.
According to OB, the moire fringes are not visually recognized in the angle range of 15 ° to 75 °, although the angular range varies depending on the period of the streaky unevenness. Therefore, the streaky unevenness in the light guide is as described above. It is desirable to form the pixel pattern of the liquid crystal display element at a predetermined angle on the basis of this, and in this case, it is possible to prevent the display quality of the liquid crystal display element from deteriorating due to moire fringes.

Further, when the above-mentioned illumination device is arranged on a reflection type liquid crystal display element, ambient light and illumination light of the illumination device are reflected by front surface reflection of the light guide, thereby affecting display quality. It is desirable to perform an anti-reflection treatment on the surface of the light guide. That is, the surface reflection can be reduced by laminating the antireflection film having the antireflection layer formed on the surface of the light guide, or by directly forming the antireflection layer on the surface of the light guide, thereby improving the display quality. Deterioration can be prevented. Alternatively, when the reflection type liquid crystal display element includes a polarizing plate and a λ / 4 plate as described above, the polarizing plate absorbs surface reflection by bonding these to the surface of the light guide. Surface reflection can be reduced, and good display quality can be obtained. In the illumination device having the above-described configuration, light that has entered the inside of the light guide from the light source via the incident surface of the light guide propagates inside the light guide using reflection at the newly formed anti-reflection processing interface. As a result, the light reaches the uneven reflection portion, and is reflected and emitted toward the emission surface.

[0066]

Embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) The configuration and operation of the lighting device 100 according to the first embodiment will be described with reference to FIGS.
This will be described with reference to FIG.

FIG. 1A is a diagram showing a display device using a reflection type liquid crystal display device 110 provided with an illumination device 100. FIG. 1B is a diagram illustrating a part of the lighting device 100 in which a part is enlarged and displayed. FIG. 2 (a)
FIG. 3 is a view of the lighting device 100 shown in FIG.

The illumination device 100 shown in FIG. 1A includes a light source 101, a light guide 102, an incident angle control means 103 disposed between the light source 101 and the light guide 102, and a light guide 1.
02 is provided with an anti-reflection film 104 bonded to the emission surface 102c. The reflective liquid crystal display element 110
Polarization selective transmission means 111, a pair of glass substrates 112a,
And 112b, glass substrate 112a and glass substrate 11
Liquid crystal layer 113 and liquid crystal layer 11 sandwiched between
3 is provided with a reflective electrode 114 disposed on the back side.

In the first embodiment, the light source 101 is
For example, as a point light source, a white LED (N
SSW440), and the point light source 101 is arranged such that the light emission direction of the point light source 101 is substantially parallel to the incident surface 102a of the light guide 102. Further, the point light source 101 is
By surrounding with 05, light is efficiently guided to the light guide. As the reflection means 105, a diffusion reflection sheet (No. 4596) manufactured by Sumitomo 3M Ltd. was used. Hereinafter, the light source 101 is referred to as a point light source 101.

The light guide 102 has an incident surface 102a on which light from the point light source 101 is incident, an exit surface 102b substantially orthogonal to the incident surface 102a, and an exit surface 102b for emitting illumination light, and a facing surface facing the exit surface 102b. 102c. Streaky irregularities 102d are periodically formed on the facing surface 102c. In the first embodiment, the light guide 102 is manufactured by injection molding polymethyl methacrylate having a refractive index of 1.49.

For the antireflection film 104, TAC-HC / AR manufactured by Nitto Denko Corporation was used. The antireflection film 104 has an effect of preventing surface reflection on the light exit surface 102c of the light guide 102. That is, since surface reflection of external light and illumination light from the illumination device is reduced, the display quality of the display device, particularly, the improvement of the contrast ratio is effective.

The reflection type liquid crystal display element 110 has a 2.5 type delta arrangement, the number of pixels of the reflection type liquid crystal display element 110 is 280 × 220, and the pixel size of the reflection type liquid crystal display element 110 is 179.5 × 168. 5 μm.

The polarized light selective transmission means 111 includes a polarizing plate, λ /
Λ / 4 plate, and λ / 4 plate is a glass substrate 1
12a. Therefore, only the linearly polarized light is selected by the polarizing plate, and the slow axis (fast axis) of the λ / 4 plate and 4
The λ / 4 plate is rotated into linearly polarized light at an angle of 5 °, and the λ / 4 plate converts the linearly polarized light into circularly polarized light. Reflective liquid crystal display element 11
0 is an image obtained by controlling the amount of light that is reflected by the reflective electrode 114 and transmitted again through the polarization selective transmission unit 111 while modulating the circularly polarized light that has passed through the polarization selective transmission unit 111 on a pixel-by-pixel basis with the liquid crystal layer 113. Is displayed.

Here, the unevenness 102d formed on the opposing surface 102c of the light guide 102 corresponds to the reflection type liquid crystal display element 110.
Designed according to. In other words, the period of the unevenness 102d and the direction of the formed streak are determined according to FIG. 20A in order to prevent deterioration in display quality due to moire fringes generated by interference with the pixel pattern of the reflective liquid crystal display element 110. .

In the first embodiment, since the reflection type liquid crystal display element 110 has a 2.5-type delta arrangement, the unevenness 102
d is formed so that the period P is 390 μm and the direction in which the unevenness 102 d extends is at an angle of 14 ° to the horizontal direction of the pixel pattern of the reflective liquid crystal display element 110 or the incident angle control means 103. With this configuration, the period of moiré fringes caused by interference between the periodically formed unevenness 102d and the pixel pattern of the reflective liquid crystal display element 110 is shortened,
The display quality of the reflection type liquid crystal display element 110 is not impaired by the observer without being recognized.

Further, of the 390 μm period of the unevenness 102d, the length P1 of the propagation portion 102e is 375 μm on average, the length P2 of the reflection portion 102f is 15 μm on average, and the height h of the unevenness h
Was set to 15 μm. Further, the length P2 of the reflection portion 102f
Is shorter than 15 μm nearer to the incident surface 102a and longer as far away from the incident surface 102a so that uniform illumination light is emitted in the plane of the light guide 102.

The light guide 102 formed as described above causes the point-like light source 101 to enter the light incident surface 10 of the light guide 102.
The light that has entered the interior through 2a
04, while propagating while repeating total reflection on the opposing surface 102c, reaching the reflecting portion 102f of the unevenness 102d,
The light that has reached 2f is reflected and emitted to the emission surface 102b. Therefore, light propagating orthogonally to the unevenness 102d is emitted most efficiently as illumination light. Therefore, in order to uniformly emit illumination light from the emission surface 102b, it is necessary for the light guide 102 to enter light perpendicular to the direction in which the unevenness 102d extends over the entire area of the incidence surface 102a.

In the first embodiment, the incident angle control means 10
3 is an incident surface 102 of the light guide 102 from the point light source 101.
Since the traveling direction of light emitted substantially parallel to a is controlled and converted into light substantially perpendicular to the direction in which the unevenness 102d formed on the light guide 102 extends, the light is uniformly emitted without generation of bright lines or dark areas. Lighting becomes possible.

The form and operation of the incident angle control means 103 will be described below with reference to FIG.

FIG. 3 is a diagram showing an optical path through which the light emitted from the point light source 101 passes through the incident angle control means 103.

The incident angle control means 103 has a plurality of prisms and is formed on the incident surface 102a of the light guide 102. The incident angle control means 103 may be formed integrally with the light guide 102. The prism of the incident angle control means 103 has a side a and a side b. The side receiving the light from the point light source 101 is called side a, and one side not in contact with the light guide 102 is called side b.

The side a is formed at an angle of 90 ° with the incident surface 102a of the light guide 102, and the side b is
It is formed so as to form an angle of 65 ° with d, and the apex angle between the side a and the side b is 39 °. Here, since the refractive index of the prism is 1.49 similarly to the light guide, the critical angle of the prism is 42 °. Therefore, the light emitted from the point light source 101 is refracted by the side a at a refraction angle of 42 ° or less and reaches the side b, and the light having an incident angle of 42 ° or more is totally reflected, and It enters inside. As described above, since the side b is formed so as to form an angle of 65 ° with the unevenness 102d, the light totally reflected on the side b is substantially orthogonal to the direction in which the unevenness 102d extends. The emitted light is effectively used as illumination light by the light guide 102.

To summarize the first embodiment, LE
In a lighting device including a point light source represented by D and a light guide having a streak-shaped concave or convex portion formed thereon, the traveling direction of light from the point light source is controlled by a plurality of prisms serving as incident angle control means. By making the light incident on the light guide substantially perpendicular to the direction in which the concave or convex portions extend, uniform illumination without any bright line or dark area was realized. In addition, by arranging the point light sources so that the light emission direction is substantially parallel to the incident surface of the light guide, each light can be projected over a wider range, and bright and uniform illumination can be achieved with a small number of point light sources. Can be emitted,
An inexpensive lighting device with low power consumption could be obtained.

Here, in the first embodiment, a plurality of prisms are integrally formed on the incident surface of the light guide as incident angle control means, but they may be formed separately. In addition, an optical unit that can emit incident light in a uniform direction can be applied. For example, a hologram may be used.

As the point light source, a tungsten lamp or the like can be used in addition to the LED.

Further, as shown in FIG. 4 (a), the reflection sheet is arranged obliquely toward the incident surface of the light guide with respect to the light emitting direction of each point light source, thereby providing a dot-like structure. Light from the light source is more efficiently incident on the incident angle control means, and brighter illumination is possible.

Alternatively, as shown in FIG. 4B, a linear light guide is arranged in the light emitting direction of the point light source, and the linear light guide converts light from the point light source into a linear light source. By emitting toward the incident angle control means, the light from the point light source is efficiently used,
The light uniformly enters the incident angle control means, and bright and uniform illumination light can be obtained.

The lighting device according to the first embodiment is the same as that shown in FIG.
Needless to say, it may be used with a liquid crystal display element other than the reflective liquid crystal display element 110 shown in FIG. Further, the lighting device according to the first embodiment may be used for a display device other than the liquid crystal display device.

The light guide 102 has the unevenness 102d formed on the surface facing the emission surface 102b. However, the unevenness 102d may be formed on the emission surface 102b.

It is preferable that the point light source 101 is arranged so that the main direction of the light emitted from the point light source 101 is not orthogonal to the incident surface 102a of the light guide 102.

Further, it is preferable that the light emitted from the point light source 101 is disposed so as to be substantially parallel to the incident surface 102a of the light guide 102.

The concave or convex reflecting portion 102f which is the unevenness 102d is located in the direction of the light emitted from the point light source 101, and the concave or convex reflecting portion which is the unevenness 102d is the light guide. Is preferably inclined toward the incident surface.

Further, the incident angle control means 103 has a plurality of prisms, and a linear light guide is arranged in the light emitting direction of the point light source 101, and the linear light guide transmits light from the point light source 101. It may be converted into a shape and emitted toward a plurality of prisms.

(Embodiment 2) The configuration and operation of the illumination device 200 according to the second embodiment will be described with reference to FIGS.
This will be described with reference to FIG.

FIG. 5A is a diagram showing a display device using a reflection type liquid crystal display element 210 provided with an illumination device 200. FIG. FIG. 5B is a diagram illustrating a part of the lighting device 200 in which a part is enlarged and displayed.

An illumination device 200 shown in FIG. 5A includes a linear light source 201, a light guide 202, an incident angle control means 203 disposed between the linear light source 201 and the light guide 202, and a light guide. There is provided a polarized light selective transmission means 204 attached to the reflection surface 202b of the body 202. Further, the reflection type liquid crystal display element 210 includes a pair of glass substrates 212a and 212
b, a liquid crystal layer 213 sandwiched between the glass substrate 212a and the glass substrate 212, and a reflective electrode 214 disposed on the back side of the liquid crystal layer 213. FIG. 6 shows FIG.
FIG. 3A is a view of the lighting device 200 shown in FIG.

In the second embodiment, a cold cathode tube is used as the linear light source 201. This cold cathode tube has electrodes (not shown) at both ends and a non-light-emitting area of 9 m due to blackening of a fluorescent agent.
m, each having a total length of 18 mm, and the length l of the effective light emitting area of the linear light source 201 is shorter than the length L of the light incident surface 202a of the light guide 202 in the longitudinal direction. A specific description of the length 1 of the effective light emitting area of the linear light source 201 will be described later. Further, by surrounding the linear light source 201 with a reflecting means 205, for example, a diffuse reflection sheet (No. 4596) manufactured by Sumitomo 3M Co., Ltd., the light emitted from the linear light source 201 can efficiently reach the light guide 202. Be guided.

The light guide 202 has an incident surface 202a on which the light from the linear light source 201 is incident, an exit surface 202b which is substantially orthogonal to the incident surface 202a and emits illumination light, and an exit surface 20b.
2b. Further, streaky irregularities 202d are periodically formed on the facing surface 202c. In the second embodiment, the light guide 202 is
It is produced by injection molding of polymethyl methacrylate.

The polarization selective transmission means 204 comprises a polarizing plate, λ /
The light guide 202 is composed of two plates and a λ / 4 plate, and a polarizing plate is bonded to the emission surface 202 b of the light guide 202. Only light incident on the polarization selective transmission means 204 is transmitted. Where λ / 4
The light reflected by the surface reflection of the plate is absorbed by the polarization selective transmission means 204 because the rotation direction of the circularly polarized light is reversed. Therefore, absorption of surface reflection is effective in improving the contrast ratio of the display device.

The reflection type liquid crystal display element 210 receives the circularly polarized light transmitted through the polarization selective transmission means 204, modulates each pixel with the liquid crystal layer 213, reflects the light with the reflection electrode 214, and passes the polarization selective transmission means 204 again. An image is displayed by controlling the amount of light generated. The reflective liquid crystal display element 210 according to the second embodiment has a 3.8-type QVGA stripe arrangement, and the number of pixels of the reflective liquid crystal display element 210 is 96.
0 × 240, and the pixel size of the reflective liquid crystal display element 210 is 81 × 234.5 μm.

The unevenness 202d formed on the opposing surface 202c of the light guide 202 is defined by the period and the direction of the streaks formed according to the reflective liquid crystal display element 210. That is, according to FIG. 20B, the period P is set to 390 μm in order to prevent deterioration of display quality due to moire fringes generated by interference with the pixel pattern of the reflective liquid crystal display element 210.
m, and the unevenness 202d is formed such that the direction in which the unevenness 202d extends forms an angle of 23 ° with the horizontal direction of the pixel pattern.

Further, in the period 390 μm of the unevenness 202d, the length P1 of the propagation portion 202e is 375 μm on average, the length P2 of the reflection portion 202f is 15 μm on average, and the height h of the unevenness 202d is 15 μm. Also, the reflection part 2
The length P2 of 02f is 15 μm closer to the incident surface 202a so that uniform illumination light is emitted in the plane of the light guide 202.
It is shorter than m and longer as it is farther.

The light guide 201 formed as described above causes the light source 201 to enter the light incident surface 202 a of the light guide 202.
Incident on the inside through the polarization selective transmission means 20
4. The light propagates while repeating total reflection on the facing surface 202c, reaches the reflecting portion 202f of the unevenness 202d, and the reflected light is emitted from the emission surface 202b. Therefore, unevenness 2
Light propagating orthogonally to the direction in which 02d extends is emitted most efficiently as illumination light.

That is, when the length 1 of the effective light emitting region of the cold cathode tube 201 is shorter than the length L of the incident surface 202a of the light guide 202, effective light is transmitted to the light guide 202 from the non-light emitting region. A dark area where no illumination light does not exist is generated. However, in the second embodiment, the traveling direction of the light emitted from the effective light emitting region of the cold cathode tube 201 is controlled by the incident angle control means 203, and the unevenness 202 formed on the light guide 202 is controlled.
Since the light is converted into light orthogonal to the direction in which d extends and is incident, uniform illumination without a dark region can be achieved.

The form and operation of the incident angle control means 203 will be described below with reference to FIG.

FIG. 7 is an enlarged view of the vicinity of the effective light emitting area of the cold cathode tube 201 in the illumination device 200.

The incident angle control means 203 is a hologram. Light having an incident angle of ± 45 ° with respect to the hologram 203 is diffracted by the hologram, and the diffracted light is substantially directed in a direction in which the unevenness 202d formed on the light guide 202 extends. Orthogonal. Here, the cold cathode tube 201 is disposed with a gap of 1 mm in order to prevent the cold cathode tube 201 from being damaged by contact with the light guide 202. Therefore, the length l of the effective light emitting area of the cold cathode tube 201 is 1 mm at each end with respect to the length L of the incident surface of the light guide 202 by the action of the hologram 203, for a total of 2
mm, and the size of the lighting device 200 can be reduced.

Hereinafter, a method for producing hologram 203 will be described with reference to FIGS. 8A and 8B.

FIG. 8A and FIG. 8B are views showing the steps of producing a hologram. In the second embodiment, for example, Omnidex 352 manufactured by DuPont is applied to the transparent substrate as the hologram 203. As shown in FIG. 8A, on a transparent substrate to which Omnidex 352 has been applied,
Two parallel light beams 501 and 502 are emitted. The two parallel light beams 501 and 502 are generated by, for example, an argon laser. Parallel light beam 501 and parallel light beam 502
And irradiating the parallel light beams 501 and 502 to record the interference fringes generated at this time on the transparent substrate coated with Omnidex 352, so that light having an incident angle of -45 ° is obtained. The transparent substrate coated with Omnidex 352 can have an effect of diffracting light in a predetermined direction.

Further, as shown in FIG.
By changing the angle between the light beam 03 and the parallel light beam 504 to generate an interference fringe again, and recording this interference fringe on a hologram on a transparent substrate coated with Omnidex 352, the incident angle becomes +
The function of diffracting 45 ° light in a predetermined direction can be imparted to the transparent substrate coated with Omnidex 352.

As described above, by using the incident angle control means using a hologram, it is possible to reduce the size of the illuminating device using a linear light source and a light guide having streak-like irregularities, and to achieve a uniform illumination without dark areas. Lighting can be obtained.

In the second embodiment, a hologram is used as the incident angle control means. However, an optical means such as a set of a plurality of prisms that can make the traveling direction of incident light uniform and emit the light is applied. be able to.

As the linear light source, in addition to a cold cathode tube, a light source that emits linear light, such as a combination of a point light source and a linear light guide, or an EL can be used as appropriate.

The lighting device according to the second embodiment is the same as that shown in FIG.
Needless to say, it may be used together with a liquid crystal display element other than the reflection type liquid crystal display element 210 shown in FIG. Further, the lighting device according to the second embodiment may be used for a display device other than the liquid crystal display device.

Further, in the light guide 202, the unevenness 202d is formed on the surface facing the emission surface 202b, but the unevenness 202d may be formed on the emission surface 202b.

[0117]

According to the present invention, the incident angle control means is disposed between the light source and the light guide, and the light from the light source is incident on the light guide in a uniform traveling direction, thereby providing a bright line or a dark line. It is possible to realize a small-sized lighting device that emits uniform illumination light without generating a region. The incident angle control means is realized by a plurality of prisms and holograms. In addition, when illuminating a liquid crystal display element with the present lighting device, it is possible to satisfactorily illuminate the liquid crystal display element by optimally designing the light guide without disturbing display quality.

[Brief description of the drawings]

FIG. 1A is a diagram showing a lighting device and a display device using a reflective liquid crystal display element according to a first embodiment of the present invention, and FIG. 1B is a diagram showing one of the lighting devices shown in FIG. It is a figure showing what expanded a part.

FIG. 2 is a view of the display device shown in FIG.

FIG. 3 is a diagram showing an optical path through which light emitted from a point light source 101 passes through an incident angle control unit 103;

FIG. 4A is a diagram illustrating another lighting device according to the first embodiment, and FIG. 4B is a diagram illustrating yet another lighting device according to the first embodiment.

FIG. 5A is a diagram showing a lighting device and a display device using a reflective liquid crystal display element according to a second embodiment of the present invention, and FIG. 5B is a diagram showing one of the lighting devices shown in FIG. It is a figure showing what expanded a part.

FIG. 6 is a view of the display device shown in FIG.

FIG. 7 is a diagram illustrating an incident angle control unit according to a second embodiment of the present invention.

FIG. 8A is a view showing a manufacturing step of the incident angle control means according to the second embodiment of the present invention.

FIG. 8B is a diagram showing a manufacturing step of the incident angle control means according to the second embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of a reflective liquid crystal display element.

10A is a diagram illustrating a delta arrangement pattern of pixels of a liquid crystal display element, and FIG. 10B is a diagram illustrating a stripe arrangement pattern of pixels of the liquid crystal display element.

FIG. 11A is a diagram of a conventional lighting device as viewed from above, and FIG. 11B is a diagram of the lighting device of FIG.

12A is a top view of a conventional lighting device, FIG. 12B is a side view of the lighting device shown in FIG. 12A, and FIG. 12C is a conventional lighting device. FIG. 5 is a view of another lighting device according to the present invention as viewed from above.

FIG. 13 is a top view of a conventional lighting device.

FIG. 14 is a top view of a lighting device according to a conventional technique.

FIGS. 15A to 15C are diagrams showing the arrangement of point light sources in the lighting device of the present invention.

FIG. 16A is a diagram showing an incident angle control means in the lighting device of the present invention.

FIG. 16B is a diagram showing an incident angle control means in the lighting device of the present invention.

FIG. 16C is a diagram showing an incident angle control unit in the lighting device of the present invention.

FIG. 17 is a diagram showing an apparatus for producing a hologram.

FIGS. 18A to 18C are diagrams showing an incident angle control unit which is a hologram.

FIG. 19 is a diagram showing an incident angle control unit which is a hologram.

FIG. 20A is a diagram illustrating the relationship between a light guide in which moire fringes do not occur and a liquid crystal display element in a delta arrangement.

FIG. 20B is a diagram illustrating the relationship between a light guide in which moiré fringes do not occur and a liquid crystal display element in a stripe arrangement.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Linear light source 12 Light guide 12a Incident surface 12b Outgoing surface 12c Opposite surface 12d Irregularity 12e Propagation part 12f Reflection part 21 Point light source 22 Light guide 22a Incident surface 22b Exit surface 22c Opposite surface 22d Irregularity 31 Point light source 32 Guide Light body 32a Incident surface 41 Point light source 42 Light guide 43 Linear light guide 100, 200 Illumination device 101, 201 Point light source 102, 202 Light guide 102a, 202a Incident surface 102b, 202b Exit surface 102c, 202c Surface 102d, 202d Unevenness 102e, 202e Propagation section 102f, 202f Reflection section 103, 203 Incident angle control means 104 Antireflection film 105, 205 Reflection means 110, 210 Reflection type liquid crystal display element 111 Polarization selective transmission means 112a, 212a Glass substrate 112b , 212b glass substrate 13,213 crystal layer 114 reflective electrode 204 polarization selective transmission means 214 reflective electrodes

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/1335 520 G02F 1/1335 520 (72) Inventor Takeshi Ebi 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka No. Sharp Corporation F term (reference) 2H038 AA52 AA55 BA06 2H091 FA08X FA11X FA14X FA14Y FA19X FA21X FA23X FA31X FA37X FA41X FC14 FC17 FD01 FD04 FD15 LA03 LA11 LA16 LA17 LA18

Claims (15)

[Claims] A light source; an incident angle control unit for receiving light emitted from the light source; an incident surface on which light emitted from the incident angle control unit is incident; and illumination light substantially orthogonal to the incident surface. A light guide having an exit surface for emitting light. The incident angle control means is disposed between the light source and the light guide, and the incident angle control means travels light emitted from the light source. A lighting device, wherein a direction is controlled, and an angle between light emitted from the incident angle control means and the incident surface of the light guide is made uniform. 2. A plurality of streaky, concave or convex portions are formed on the light exit surface of the light guide or on a surface facing the light exit surface, and the concave or convex portions are formed from the light incident surface. The light that enters and propagates through the light guide is refracted and reflected to emit illumination light from the emission surface, and the direction in which the concave or convex portion extends is substantially orthogonal to the light emitted from the incident angle control means. The lighting device according to claim 1, wherein: 3. The concave or convex portion is formed on the opposite surface of the light guide, and the concave or convex portion enters the inside of the light guide via the incident surface of the light guide. The lighting device according to claim 2, further comprising: a propagating portion that substantially propagates the generated light; and a reflecting portion that substantially reflects the light toward the emission surface of the light guide. 4. The light source according to claim 1, wherein the light source is a point light source.
The lighting device according to any one of the preceding claims. 5. The point light source according to claim 4, wherein the point light source is disposed such that a main direction of light emitted from the point light source is not orthogonal to an incident surface of the light guide. Lighting equipment. 6. The lighting device according to claim 5, wherein the direction of the light emitted from the point light source is arranged so as to be substantially parallel to the incident surface of the light guide. 7. The lighting device according to claim 6, wherein a reflection sheet is arranged near the point light source, and the reflection sheet is inclined toward an incident surface of the light guide. . 8. The incident angle control means has a plurality of prisms, and a linear light guide is arranged in a light emitting direction of the point light source, and the linear light guide linearly transmits light from the point light source. The illumination device according to claim 6, wherein the light is converted into a shape and emitted toward the plurality of prisms. 9. The light source is a linear light source, the length of the effective issuance area of the linear light source is shorter than the longitudinal direction of the incident surface of the light guide, and the incident angle control means is The light traveling direction of the light from the linear light source is controlled, and light having a uniform incident angle is made incident on the entire incident surface of the light guide, according to any one of claims 1 to 3, wherein Lighting equipment. 10. The incident angle control means is a plurality of prisms, and the incident angle control means refracts and reflects light emitted from the light source, aligns the traveling direction of the light, and adjusts the direction of the light guide. 10. The method according to claim 1, wherein the light is incident on an incident surface.
The lighting device according to any one of the above. 11. The lighting device according to claim 10, wherein the plurality of prisms are formed on the incident surface of the light guide. 12. The plurality of prisms are arranged toward the light source, and an angle α between at least one side of the prism and streaky irregularities formed in the light guide is 40 ° ≦ α <90. °
The lighting device according to claim 10 or 11, wherein the following condition is satisfied. 13. The prism according to claim 1, wherein the apex angle β is 0 ° <
The angle β satisfies β <80 °.
The lighting device according to any one of the preceding claims. 14. The apparatus according to claim 1, wherein the incident angle control means is a hologram, and controls a traveling direction of light from the light source to make incident angles of the light guide with respect to the incident surface uniform. 10. The lighting device according to one of claims 9. 15. A display device, comprising: the lighting device according to claim 1; and a liquid crystal display element.