JP2000292789A - Illuminating device and display device equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an illuminating device and a display device equipped with this illuminating device in which production of double images or interference fringes can be suppressed, bright high-quality display with a good contrast ratio can be performed, scratches in the recesses and projections and modification of a reflecting means and warpage of a light transmitting body can be decreased to increase reliability, and a thin, lightweight and low-cost device can be obtd. SOLUTION: This illuminating device 100 consists of a light source 101, a light- transmitting body 102, and a reflecting means 103 separately formed or disposed from the light-transmitting body 102. The light transmitting body 102 has an entrance face 102a where the light from the light source 101 enters, an exiting face 102b where the illuminating light exits and a counter face 102c facing the exiting face 102b, with the both faces almost perpendicular to the entrance face 102a. The reflecting means 103 are formed or disposed on the exiting face 102b or the counter face 102c of the light transmitting body 102. In this structure, the light which is emitted from the light source 101 and enters the entrance face 102a of the light-transmitting body 102 to propagate in the light-transmitting body 102 is reflected by the reflecting means 103 to exit as the illuminating light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device and a display device provided with the lighting device and a reflective liquid crystal display element.

[0002]

2. Description of the Related Art A liquid crystal display device, which is one of display devices used for an information display system, an OA device, and the like, is of a transmission type that displays an image by controlling a transmitted light amount of light emitted from the outside, and a reflected light amount. And a reflection type that displays an image by controlling the

[0003] A transmissive liquid crystal display device is generally used with an illuminating device called a backlight disposed on the back surface.

[0004] The reflection type liquid crystal display device can display using ambient light. However, the degree of display luminance greatly depends on the surrounding environment, 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 necessary in case sufficient ambient light cannot be obtained.

FIG. 16 shows a configuration example of the reflection type liquid crystal display device.

This reflective liquid crystal display device has a reflective liquid crystal display element 900 in which a liquid crystal layer 903 is sandwiched between a pair of glass substrates 902a and 902b, and a reflective electrode 904 is provided on the rear glass substrate 902b. And the liquid crystal layer 90
A polarizing plate 901a and a λ / 4 plate 901b are arranged on the front side of the light emitting element 3. Transmission axis (or absorption axis) of polarizing plate 901a
And the slow axis (or fast axis) axis of the λ / 4 plate 901b is 45 °
Are arranged at an angle.

[0007] Of the illumination light, linearly polarized light transmitted through the polarizing plate 901 a is converted into circularly polarized light by the λ / 4 plate 901 b and enters the liquid crystal layer 903. Here, when the liquid crystal layer 903 does not modulate the circularly polarized light, the direction of rotation of the circularly polarized light is reversed when the liquid crystal layer 903 reflects the light on the reflective electrode 904, and after transmitting through the λ / 4 plate 901 b again, the transmission axis of the polarizing plate 901 a is transmitted. Since the light is absorbed as linearly polarized light orthogonal to the light, black is displayed.

The liquid crystal layer 903 of the reflection type liquid crystal display element 900
However, when the incident circularly polarized light is modulated so as to be reflected while being preserved, the light is transmitted through the λ / 4 plate 901b and then emitted as linearly polarized light that matches the transmission axis of the polarizing plate 901a. Is displayed.

The transmission axis of the polarizing plate 901a and the λ / 4 plate 9
The direction of the slow axis of 01b is determined in consideration of the liquid crystal material, the direction of the alignment, the characteristics of the viewing angle, and the like. Further, in order to compensate for the tolerance of the phase delay with respect to the wavelength of the light of the λ / 4 plate 901b, the λ / 4 plate 901b is placed between the polarizing plate 901a and the λ / 4 plate 901b.
Two plates may be arranged. Generally, the polarizing plate 901a, the λ / 2 plate, and the λ / 4 plate 901b are integrated with each other via an adhesive layer, and are attached to the reflective liquid crystal display element 900.

The reflection electrode 904 disposed on the back surface of the liquid crystal layer 903 has a microstructure (MRS) formed on the surface, and the light incident through the polarizing plate 901a, λ / 2 plate, and λ / 4 plate 901b. The light is scattered and reflected so that uniform display can be performed in a wide viewing angle range. Specifically, an MRS as a base layer is formed by a photolithography process, and a reflective electrode 904 is formed by vacuum-depositing Al thereon.

The reflection electrode 904 provided with such an MRS
3 is shown in FIG. 3 in comparison with the scattering characteristics of a standard white plate (MgO). According to this, it can be seen that the reflective electrode provided with the MRS can efficiently scatter and reflect light incident within an incident angle of 30 ° in the front direction.

As described above, characters and images are displayed by controlling the modulation by the liquid crystal layer 903 for each pixel, and the red (R), green (G), and blue (B) disposed in each pixel are displayed.
A color display can be performed by transmitting and coloring through the three primary color filters. Although there are various arrangement patterns of R, G, and B pixels, typical examples include a delta arrangement and a stripe arrangement shown in FIG. 17, and the arrangement is such that pixels are repeatedly arranged in the horizontal and vertical directions. The number of pixels and the size of the pixels are also various. In the case of the reflection type liquid crystal display element of the delta arrangement, the number of horizontal pixels × the number of vertical pixels is 280 × 220 in the 2.0 type, and the pixel size is 145.5 μm in the horizontal direction. The vertical direction is 138.5 μm, and the 2.5-inch type adopts the following specifications: the number of pixels is 280 × 220, and the pixel size is 179.5 × 168.5 μm. In a stripe arrangement, for example, a 3.8 QV
In the case of a GA reflective liquid crystal display element, the number of pixels is 960 × 2
40 and a pixel size of 81 × 234.5 μm.

By the way, the above-mentioned front light has been conventionally proposed. For example, SID (Society)
for Information Display
y) '95 Digest p. 375 (conventional example 1) shows a front light having the configuration shown in FIG. The front light 910 includes a light source 911, an incident surface 912a on which light from the light source 911 is incident, and a light guide 912 having an emission surface 912b and a facing surface 912c substantially perpendicular thereto. Opposing surface 91 of light guide 912
2c are formed with periodic irregularities 913, and the irregularities 913 are formed in a propagation portion 913a substantially parallel to the emission surface 912b.
And an inclined reflecting portion 913b.

In the front light 910, the light source 91
1 from the direct or output surface 912b and the opposing surface 91.
Propagation part 913a of periodic unevenness 913 formed in 2c
Is totally reflected by the light guide 912 and propagates inside the light guide 912, and
Reflector 913 of periodic unevenness 913 formed on 12c
b, and is reflected and emitted toward the emission surface 912b. Therefore, the emission surface 912b, that is, the front light 9
Illumination light from the exit surface of the liquid crystal display device 920
Is irradiated.

[0015]

However, the conventional front light 910 and the reflection type liquid crystal display element 920 described above.
In the display device described above, the opposing surface 912c of the light guide 912
Since the unevenness 913 formed on the top surface appears on the outermost surface, the unevenness 913 is easily damaged, and has serious problems in terms of deterioration of front light performance, display quality, productivity, reliability, and the like.

When the light reflected by the reflection type liquid crystal display element 920 passes through the light guide 912, the light is reflected by the light guide 912.
Propagation part 913a and reflection part 91 of unevenness 913 formed in
3b is refracted in different directions, which causes a problem that the display of the reflective liquid crystal display element 920 is observed twice.

Further, due to the periodically formed irregularities 913, two types of light and dark fringes described below are generated,
There is a problem that the display quality of the reflective liquid crystal display element 920 is reduced.

First, the reason why the first light and dark fringes occur will be described. From the light source 911 to the entrance surface 91 of the light guide 912
Light incident through the light guide 2a propagates through the light guide 912 and is reflected toward the emission surface 912b by the periodic irregularities 913 formed on the opposing surface 912c, and most of the light from the light guide 912 Emitting and reflecting liquid crystal display element 920
To illuminate. However, about 4% of the surface reflection on the emission surface 912b is reflected and passes through the periodic unevenness 913 on the facing surface 912c to reach the observer. Therefore, the observer sees the light from the periodically arranged unevenness 913 through the periodic unevenness 913, so that the first light and dark fringes are observed. Similarly, the first light and dark fringes are generated by reflection on the surface of the reflective liquid crystal display element 920.

The second bright and dark fringes are the periodic light that is formed by the reflection on the periodic irregularities 913 passing through the pixel pattern of the reflective liquid crystal display element 920, being reflected and formed on the light guide 912 again. Three periods occur due to interference due to passing through the irregularities 913. Without turning on the front light 910, the reflection type liquid crystal display
Is illuminated, the illumination light passes through the periodic irregularities 913 formed on the light guide 912 and the pixel pattern of the reflective liquid crystal display element 920, is reflected and is again reflected by the periodic irregularities 91.
3, a second light and dark fringe is generated due to interference of these periods.

The first bright and dark fringes are suppressed by reducing the surface reflection by disposing an antireflection layer on each of the emission surface 912b of the light guide 912 and the surface of the reflective liquid crystal display element 920. be able to. Here, the anti-reflection layer is a layer formed by a method such as vapor deposition or sputtering and having a thickness of about 0.1 μm and made of MgF ₂ , SiO _2, or the like, which reduces reflection energy by an interference action of the thin film. Say. Therefore, for example, an antireflection film in which an antireflection layer is formed on a transparent film serving as a substrate
The surface reflection can be easily reduced by bonding to the second emission surface 912b, and the generation of the first light and dark fringes can be suppressed.

However, when the ambient temperature changes, warpage occurs due to the difference in the thermal expansion coefficient between the light guide 912 and the antireflection film, and a new problem arises in terms of reliability. Although a method of forming the above-described anti-reflection layer directly on the surface of the light guide 912 is also conceivable, since a thin film such as evaporation or sputtering is formed in a high-temperature environment, a heat-resistant material is applied to the light guide 912. In addition, there is a problem with the adhesion of the antireflection layer, and there is a concern about reliability.

In order to solve such a problem, the above-mentioned conventional example 1 includes:
A front light is used to protect the unevenness 913 formed on the light guide 912 and to prevent a double image, first light and dark fringes, and second light and dark fringes from occurring in the display of the reflective liquid crystal display element 920. Also, a configuration in which an optical compensator is added to the above is described.

In this front light, as shown in FIG. 18B, the optical compensator 914 has compensation irregularities 915 in which irregularities 913 formed on the opposing surface 912c of the light guide 912 are transferred. Light guide 912 and optical compensator 91
In No. 4, the two concavities and convexities face each other via an air layer.

Therefore, the reflected light from the reflective liquid crystal display element 920 receiving the illumination light is refracted in different directions when passing through the propagation portion 913a and the reflection portion 913b of the unevenness 913 formed on the light guide 912. However, the light refracts again when passing through the unevenness 915 of the optical compensator 914, so that the light travels in the same manner as when there is no unevenness. By disposing the optical compensator 914 having such a function, the light guide 912
Unevenness 913 can be protected. Further, the reflection type liquid crystal display element 2 caused by the periodically formed unevenness 913
It is possible to prevent the occurrence of a double image in the display of 0 and the occurrence of the first light-dark fringe and the second light-dark fringe.

However, the addition of the optical compensator 914 creates another new problem. For example, in order to obtain the above-described compensation effect, the gap between the light guide 912 and the optical compensator 914 must be as small as possible. However, if the gap is not uniform, interference fringes occur. Therefore, it is necessary to install the optical compensator 914 on the light guide 912 with very high accuracy. In addition, since reflection by a new interface of the optical compensator 914 is added,
There is a problem in that the light reflected toward the observer increases, the transmittance decreases, and the display of the reflective liquid crystal display element 920 becomes dark, thereby lowering the display contrast ratio. Further, there is a problem that the thickness of the display device is increased due to an increase in thickness.

The present invention solves the above-mentioned problems of the prior art, and can suppress the occurrence of double images and bright and dark stripes, and can provide a bright, high-contrast, high-quality display. It is an object to provide a device and a display device provided with the device.

Another object of the present invention is to provide a lighting device and a display device having the same, which can reduce the damage and deterioration of the unevenness in the reflecting means and the warpage of the light guide, and can improve the reliability. To provide.

Another object of the present invention is to provide a lighting device which can be reduced in thickness, weight and cost, and a display device provided with the same.

[0029]

According to the present invention, there is provided an illuminating apparatus comprising: a light source; an incident surface on which light from the light source is incident; an exit surface substantially perpendicular to the incident surface, from which illumination light exits; A light guide having an opposing surface opposing the surface, and a reflecting means formed or arranged separately from the light guide on the emission surface or the opposing surface of the light guide, and the light guide is provided from the light source. The light that enters through the incident surface of the body and propagates inside the light guide is reflected by the reflection means to emit illumination light, thereby achieving the above object.

The illuminating device of the present invention has a configuration in which a transparent flat plate and a reflecting means are opposed to each other to form a light guide space, and a light source is arranged on an end face of the light guide space. Light incident on the light guide space and propagating through the light guide space is reflected by the reflection means to emit illumination light, thereby achieving the above object.

Preferably, the reflection means reflects the light by the difference in the refractive index of the interface of the uneven shape.

Preferably, the reflecting means is composed of a combination of two members having different refractive indices, and the interface between the two members has an uneven shape, and reflects light by a difference in refractive index between the interfaces. It has a certain configuration.

Preferably, the concave and convex shape of the reflecting means has a prism shape, and has a propagating portion substantially parallel to an emission surface of the light guide and an inclined reflecting portion. Light that enters through the incident surface of the body and propagates mainly through the propagation section is reflected by the reflection section to emit illumination light.

Preferably, the concave and convex shape of the reflecting means has a prism shape, and has a refracting portion and a reflecting portion inclined with respect to the transparent flat plate, and the light incident on the light guide space from the light source. Is refracted at the interface of the refraction portion, and is reflected by the reflection portion to emit illumination light.

Preferably, when the uneven shape of the reflecting means is α, the total reflection angle due to the difference in the refractive index at the interface of the reflecting portion is α, the reflecting portion is formed on the exit surface of the light guide or the transparent flat plate. The angle β formed with the lens satisfies the following equation (1): α−30 ° ≦ β ≦ α + 30 ° (1)

Further, a display device of the present invention includes a lighting device according to any one of the above, and a reflection type liquid crystal that receives illumination light from the lighting device and controls the reflectance for each pixel to display an image. A display element, whereby the above object is achieved.

The operation of the present invention will be described below.

According to the above configuration, the light guide has the incident surface on which the light from the light source enters, the exit surface substantially perpendicular to the entrance surface, and the opposing surface facing the exit surface. Propagates light incident from a surface. Reflecting means formed or arranged separately from the light guide on the light emitting surface or the opposing surface of the light guide reflects light propagating inside the light guide and emits illumination light.

The reflecting means can be configured to reflect light according to the difference in the refractive index at the interface of the uneven shape. The reflecting means may be configured by a combination of two members having different refractive indices, and an interface between the two members may have an uneven shape, and light may be reflected by a difference in refractive index at the interface.

Specifically, when the uneven shape is formed integrally with the light guide, the light guide is formed by using a transparent resin typified by an acrylic resin, a polycarbonate resin, an epoxy resin, or the like as the material. The body and the reflecting means can be molded simultaneously.

In the case where the uneven shape is formed separately from the light guide, the uneven shape is formed on the emission surface or the opposing surface of the light guide in addition to acrylic resin, polycarbonate resin, epoxy resin, etc. Molding can be performed using a transparent resin such as a thermosetting resin, and the choice of materials can be increased. That is, it is possible to select a material having reliability such as hardness and chemical resistance in the uneven shape.

According to the above construction, the light guide has a flat exit surface and a facing surface, so that the choice of materials can be increased. For example, if glass is selected, the rigidity is higher than that of a transparent resin. Even when an anti-reflection film or the like is attached to a plane on which the reflection means is not provided to improve the transmittance of the light guide, the warpage caused by a temperature change or the like can be reduced, and the reliability can be increased.

When the reflection means uses a reflection sheet, the transmittance of the light guide is improved by bonding the reflection sheet and the antireflection film to the light exit surface and the opposite surface, and the both are balanced. By taking this measure, it is possible to further reduce the warpage of the light guide caused by a temperature change or the like. Further, it is desirable that the films serving as both substrates are the same.

In the case where the reflecting means has a structure having a member having irregularities and a refractive index layer having a different refractive index, preferably a low refractive index, formed on the irregularities, the illumination device may be damaged due to unevenness or deterioration of the irregularities. Can be prevented from deteriorating. Here, the unevenness can be formed separately from the light guide on the light emitting surface or the opposing surface of the light guide, or may be a reflection sheet having unevenness formed on a transparent film, and a refractive index having a different refractive index. Reflection means can be used in combination with a layer. Further, the projections and depressions may be integrally formed on the emission surface or the opposing surface of the light guide, and may be combined with a refractive index layer having a different refractive index to form a reflection unit.

In the case where the above-mentioned reflecting means is arranged on the opposite surface of the light guide, an antifouling film (water-repellent layer), a hard coat layer and the like are formed on the surface of the low refractive index layer, so that the surface of the lighting device is formed. Reliability can be improved, and the reflectance of the surface can be reduced by forming the antireflection layer. The antifouling film (water repellent layer), hard coat layer and antireflection layer can be easily obtained by disposing a protective film on which these are formed in advance on the surface of the low refractive index layer.

When the reflecting means is disposed on the light emitting surface of the light guide, the unevenness is protected by the light guide, so that the reliability of the reflecting means can be improved. Further, an antifouling film (water repellent layer), a hard coat layer, and an anti-reflection layer may be formed on the surface of the reflection means where the unevenness is not formed.

If the concave-convex shape of the reflecting means is a prism-like shape composed of a propagation portion substantially parallel to the light exit surface of the light guide and an inclined reflection portion, the light source passes through the entrance surface into the light guide through the incident surface. The incident light propagates inside the light guide while repeating reflection at the light emitting surface, the opposite surface, or the uneven propagation portion, reaches the reflection portion, and is reflected by the refractive index difference at the interface. Out as illumination light. Therefore, when the unevenness in the reflecting means forms an interface with an air layer or a refractive index layer having a lower refractive index than the unevenness, total reflection occurs, and illumination light can be emitted more efficiently.

When the total reflection angle due to the refractive index difference at the interface of the reflecting portion is α,
The angle β formed by the reflecting portion with respect to the light exit surface of the light guide is α-3.
0 ° ≦ β ≦ α + 30 ° It is desirable to adopt a configuration satisfying the relationship of the expression (1).

This is because, as shown in FIG. 3, in the reflection type liquid crystal display device, the reflection characteristics of the reflection electrode on which the fine structure is formed are necessary to efficiently illuminate the reflection type liquid crystal display device and obtain a bright display. Is caused by the need to illuminate within an incident angle of 30 °.

More specifically, for example, as shown in FIG. 6A, when the angle β formed by the uneven reflecting portion with respect to the light exit surface of the light guide is (α−30 °), the reflecting portion In the light totally reflected at the interface, there is light having an emission angle of 30 ° with respect to the emission surface.

As shown in FIG. 6B, when β = α, the light totally reflected at the interface of the reflecting portion includes light emitted at an emission angle of 0 ° with respect to the emission surface, and the light is efficiently reflected. Type liquid crystal display device.

As shown in FIG. 6C, β = (α + 30
°), illumination light having an emission angle of 30 ° or less with respect to the emission surface is generated. However, if β> (α + 30 °), illumination light with an emission angle of 30 ° or more with respect to the emission surface increases, and the reflection type Not suitable for lighting liquid crystal display elements.

On the other hand, considering only the amount of illumination light emitted from the illumination device, the amount of light increases as β approaches 0 °, and decreases as β increases.

Therefore, considering both the emission angle and the light amount of the illumination light, the reflecting portion is positioned at (α-30) with respect to the emission surface of the light guide.
°) and (α + 30 °) or less.

Next, a method for evaluating deterioration of display quality due to a double image of display of the reflection type liquid crystal display device will be described.

As shown in FIG. 8, a reflection type liquid crystal display element 32 having a light guide 31 disposed on the front face is connected to a light source 30 such as a fluorescent lamp.
Then, the observer 37 observed the display, and evaluated the degree of deterioration of the display quality due to the double image of the display at this time. FIG. 9 shows the relationship between the ratio (P2 / P1) of the reflection portion and the propagation portion of the unevenness obtained as a result of the evaluation and the double image. In FIG. 9, a circle indicates that the double image is not observed and the display quality is good, and a triangle indicates that the double image is slightly generated but does not hinder display recognition. The crosses indicate that the double image is remarkable and adversely affects the display quality. According to FIG. 9, the ratio (P2
It can be seen that if / P1) is 0.2 or less, there is an effect on double images, and if it is 0.05 or less, good display quality can be obtained.

Therefore, the ratio (P2) of the length (P2) of the reflection portion to the length (P1) of the propagation portion of the unevenness as the reflection means.
/ P1) is greater than 0 and less than or equal to 0.2, so that the observer 37 views the display of the reflective liquid crystal display element mainly through the propagation portion of the unevenness, and passes through the reflection portion. Thus, a double image generated by light reaching the observer 37 can be suppressed.

When the anti-reflection layer is arranged on the surface of the lighting device as described above, the surface reflection of the lighting device can be reduced and the transmittance can be improved. When applied to the lighting device of (1), it is possible to provide a display device which is bright, has a good contrast ratio, and can display a clear image. It is desirable that an anti-reflection layer is also formed on the surface of the reflective liquid crystal display element. In this case,
A brighter display device with a good contrast ratio can be realized.

By the way, as described above, in the case where the uneven shape as the reflecting means is formed periodically, in the lighting device provided with the light, the light reflected by the unevenness at the time of lighting is emitted from the emission surface of the lighting device, and Since the light is reflected on the surface of the reflection type liquid crystal display element and passes through the unevenness again to reach the observer, the first light and dark fringes due to the interference of the unevenness occur.

However, as described above, by suppressing the surface reflection by forming an anti-reflection layer on the emission surface of the illumination device and the surface of the reflection type liquid crystal display element, it is possible to suppress the occurrence of the first bright and dark fringes. Can be.

Alternatively, when the reflection type liquid crystal display element is configured to display an image using polarized light transmitted through the polarization selective transmission means, the polarization selective transmission means may be attached to the light exit surface of the light guide. The generation of the first light and dark fringes can be suppressed.

Because, as described above, the transmission axis or absorption axis of the polarizing plate and the slow axis or fast axis of the λ / 4 plate are 45 °.
The polarized light selective transmission means arranged so as to make the angle of (2) is rotated in the reverse direction when the transmitted circularly polarized light is reflected, and is thus absorbed by the polarizing plate when it reaches the polarized light selective transmission means again. Therefore, by attaching the polarized light selective transmission means to the emission surface of the illumination device, the reflected light at the rear side of the polarized light selective transmission means, that is, at the surface of the polarized light selective transmission means and the reflection type liquid crystal display element can be absorbed. The occurrence of light and dark stripes can be suppressed. Further, for the same reason, a display device with a good contrast ratio can be provided.

Further, by arranging the anti-reflection layer on the surface of the polarization selective transmission means and the reflection type liquid crystal display element, it is possible to reduce the reflected light and increase the transmitted light, so that a brighter display is possible. .

When a touch panel is added as an input device to a display device including a reflective liquid crystal display element and a lighting device, the light guide and the touch panel may be used. In other words, the surface of the touch panel on the side of the reflective liquid crystal display element is the emission surface of the light guide, and the surface on the observer side is the facing surface of the light guide. The light incident through the incident surface of the light body is reflected by the reflection means, emitted from the illumination device as illumination light, and illuminates the reflective liquid crystal display element.

The reflection means can be obtained by forming irregularities of a transparent resin on the surface of the touch panel. Alternatively, it can be configured by attaching a reflective sheet having irregularities formed of a transparent resin on the surface of a transparent film. Further, a refractive index layer having a different refractive index, preferably a low refractive index, may be formed on the unevenness of the member having the unevenness to serve as a reflection means, and may be disposed on the surface of the touch panel. It is desirable that the reflection means be arranged on the reflection type liquid crystal display element side of the touch panel, that is, on the light emitting surface of the light guide. This is because the viewer side of the touch panel receives an input by using a touch pen or the like, and therefore, if the projections and depressions are provided here, the projections and depressions will be damaged, and the performance of the lighting device will be degraded due to deformation, thereby affecting display quality. .

According to this configuration, it is possible to avoid an increase in the size of the device caused by providing both the light guide and the touch panel as in a conventional display device, and it is inexpensive, thin, lightweight, and excellent in portability. A display device can be realized.

In a lighting device having a light guide space, the transparent flat plate and the reflection means are arranged to face each other to form a light guide space,
The light source is disposed on an end surface of the light guide space. Then, the light that enters the light guide space from the light source and propagates in the light guide space is reflected by the reflection unit and exits from the lighting device as illumination light.

In this lighting device, the reflecting means is constituted by a large number of irregularities. Therefore, when the present illuminating device is used for a reflective liquid crystal display element, the reflecting means is a large number of irregularities arranged on the surface of the transparent film, and the reflective film formed of the transparent film and the large number of irregularities forms the reflective liquid crystal. It is attached to the surface of the display element. Alternatively, a large number of concavities and convexities may be directly formed on the surface of the reflective liquid crystal display element to serve as a reflection means. The irregularities can be formed by molding with a transparent resin such as an acrylic resin, a polycarbonate resin, or an epoxy resin, an ultraviolet curable resin, a thermosetting resin, or the like. A transparent flat plate and a glass plate made of a transparent resin can be used as the transparent flat plate disposed to be substantially parallel thereto. When a touch panel is provided as an input device, the touch panel can be applied as a transparent flat plate. It is desirable that the surface of these transparent flat plates be subjected to antireflection treatment to reduce surface reflection and improve transmittance, and this configuration can realize a display device that is bright and has a good contrast ratio.

According to the above configuration, the weight of the lighting device can be reduced by utilizing the light guide space.

If the projections and depressions of the reflecting means are configured to have two inclined portions inclined with respect to the transparent flat plate forming the light guide space, that is, a prism shape having a refraction portion and a reflection portion, the light guide space can be provided from the light source. Is incident on the light guide space while repeating reflection by the transparent flat plate and the reflection means, reaches the unevenness, and is refracted at the interface of the refraction part due to a difference in the refractive index at the interface. The light is reflected at the interface, and the reflected light is emitted as illumination light.

When the concave and convex shape of the reflecting means is such that α is the total reflection angle due to the refractive index difference at the interface of the reflecting portion,
The angle β formed by the reflection section with respect to the transparent flat plate arranged substantially parallel to the reflection means and the reflection type liquid crystal display element is α−30 ° ≦
β ≦ α + 30 ° It is desirable to adopt a configuration that satisfies the relationship of Expression (1).

More specifically, for example, as shown in FIG. 7A, the angle formed by the reflection portion with respect to the transparent flat plate, that is, the angle β formed with respect to the reflection type liquid crystal display element is (α−30 °). In this case, the light totally reflected at the interface of the reflection portion includes light having an angle of incidence of 30 ° with respect to the perpendicular of the transparent flat plate, that is, an angle of incidence of 30 ° with respect to the reflective liquid crystal display element.

As shown in FIG. 7 (b), when β = α, the light totally reflected at the interface of the reflecting portion is incident on the perpendicular line of the transparent flat plate or at an incident angle of 0 ° with respect to the reflective liquid crystal display device. Angled light exists, and the reflective liquid crystal display element can be efficiently illuminated.

As shown in FIG. 7C, β = (α + 30
In the case of (°), illumination light is generated in which the angle with respect to the perpendicular of the transparent flat plate and the incident angle with respect to the reflective liquid crystal display element are 30 ° or less. However, if β> (α + 30 °), then
The amount of illumination light whose angle with respect to the perpendicular of the transparent flat plate and the incident angle with respect to the reflective liquid crystal display element is 30 ° or more increases, which is not suitable for illumination of the reflective liquid crystal display element.

Therefore, by designing the angle β formed by the reflection portion with respect to the transparent flat plate according to the above equation (1), the reflection type liquid crystal display element can be efficiently illuminated and a bright display can be performed.

Considering the double image of the display of the reflection type liquid crystal display element caused by the unevenness in the reflecting means, the results shown in FIG. 9 show that the unevenness which is the reflecting means is not formed in the illumination device using the light guide space. The ratio (P) of the region (P2 ′) where the unevenness is formed to the region (P1 ′)
2 '/ P1') is greater than 0 and less than or equal to 0.2,
It can be seen that the display of the reflective liquid crystal display element is not observed twice, and a good display quality can be obtained.
More preferably, the ratio (P2 ′ / P1 ′) is set to 0.05.
A clear display can be provided by the following.

When an illuminating device having a light guide space is arranged in front of a reflection type liquid crystal display element to illuminate the same, a glass plate, a transparent resin plate, or a touch panel can be applied to the transparent flat plate. By applying an anti-reflection treatment to these transparent flat plates, the transmittance of the illuminating device is improved, and a bright and high-contrast display device can be realized.

When the unevenness of the reflecting means is periodically formed in the illumination device having the above-described structure, the direction of the streak is
It is desirable to dispose the liquid crystal display element so as not to coincide with the horizontal direction of the repetition of the pixel pattern.

When an illumination device provided with a reflecting means having periodic unevenness is arranged as a front light in front of a reflective liquid crystal display element, the unevenness of the reflecting means interferes with the pixel pattern of the reflective liquid crystal display element. A second light and dark fringe is generated, but by giving an angle between the direction of the streaks on which the irregularities are formed and the direction of the repetition of the pixel pattern, the period of the second light and dark fringe is shortened, and eventually the second light and dark fringe is not observed. This is because a phenomenon occurs.

More specifically, FIG. 4 shows an illumination device provided with a reflection means having periodic irregularities formed in front of a reflection type liquid crystal display device having a delta arrangement of 2.0 type and 2.5 type. The results of observing the second light and dark fringes by giving an angle between the direction of the stripes of the unevenness and the horizontal direction of the pixel pattern and finding the angle range in which the second light and dark fringes are not observed are shown. FIG. 5 shows the results of a similar experiment performed on a reflection type liquid crystal display device having a 3.8-type QVGA stripe arrangement.

According to FIGS. 4 and 5, although the angular range varies depending on the period of the unevenness, when the reflective liquid crystal display element has a delta arrangement, the angle is 10 ° to 25 ° and 55 ° to 80 °. In the case of the range and the stripe arrangement, the second light and dark fringes are not observed in the angle range of 15 ° to 75 °, and good display quality can be obtained.

[0082]

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

(Embodiment 1) FIGS. 1 and 2 show an example of the configuration of an illuminating device according to Embodiment 1 of the present invention and a display device using a reflective liquid crystal display device having the illuminating device.

In the first embodiment, as shown in FIGS. 1 and 2, a lighting device 100 includes a light source 101, a light guide 102,
It comprises a reflection means 103 and an antireflection film 104. The reflection type liquid crystal display element 110 includes a polarization selective transmission unit 111, a pair of glass substrates 112a and 112b,
It is composed of a liquid crystal layer 113 sandwiched therebetween and a reflective electrode 114 disposed on the back side thereof.

More specifically, a fluorescent tube was used as the light source 101, and a glass plate having a refractive index of 1.53 was used as the light guide 102. Here, in the light guide 102, the lighting device 100
The surface on the side from which the illumination light exits is referred to as an exit surface 102b, and the surface opposite thereto is referred to as an opposing surface 102c. The reflecting means 103 formed by irregularities formed separately from the light guide 102 on the opposing surface 102c of the light guide 102 is made of a UV curable resin, GRNDDICRC-872 manufactured by Dainippon Ink and Chemicals, Inc.
0 was used. This UV-curable resin has a refractive index after curing of 1.52 and a rigidity of 2.1 × 10 ¹⁰ dyn / cm ² . Therefore, the refractive index is almost equal to the glass plate, and
Since the rigidity is high, it is hard to be damaged and high reliability can be obtained. Apply this UV curable resin on a glass plate,
Further, the mold is arranged, the resin is cured by irradiating ultraviolet rays from the glass plate side, and the shape of the mold is transferred, whereby the reflection means 103 by the unevenness can be formed.

For the anti-reflection film 104, a TAC-HC / AR manufactured by Nitto Denko Corporation having an anti-reflection layer formed on a TAC film as a transparent base material is used.
2 through the adhesive layer.

The reflection type liquid crystal display element 110 has a 2.0 type delta arrangement, the number of pixels is 280 × 220, and the pixel size is 145.5 × 138.5 μm.

As shown in the partially enlarged view of FIG. 2, the polarization selective transmission means 111 includes a polarizing plate 111a and a λ / 2 plate 111.
b and the λ / 4 plate 111c are bonded in this order via an adhesive layer, and the λ / 4 plate 111c is
2a. This polarization selective transmission means 11
As for the light incident on 1, only the linearly polarized light is selected by the polarizing plate 111a, and the λ / 2 plate 111b rotates to the linearly polarized light having an angle of 45 ° with the slow axis (or the fast axis) of the λ / 4 plate 111c. Then, the λ / 4 plate 111c converts linearly polarized light into circularly polarized light.

Therefore, the reflection type liquid crystal display element 110 converts the circularly polarized light, which has passed through the polarization selective transmission means 111, out of the ambient light or the illumination light from the illumination device 100 into the liquid crystal layer 11 for each pixel.
An image is displayed by controlling the amount of light that is reflected by the reflection electrode 114 and passes through the polarization selective transmission unit 111 again while being modulated by the modulation signal 3.

The reflective electrode 114 has a fine structure (MRS) formed on its surface in order to scatter and reflect the incident light to provide an image of good display quality in a wide viewing angle range.
Has scattering characteristics as shown in FIG.

Next, the reflection means 103 using unevenness will be described. As shown in the partially enlarged view of FIG. 1, the irregularities are formed in the propagation portion 103a substantially parallel to the emission surface 102b of the light guide 102.
And a reflecting portion 103b inclined with respect to the emission surface 102b. Therefore, the light from the light source 101 is
The light incident on the inside through the incident surface 102a and propagated while repeating total reflection reaches the uneven reflection portion 103b, is totally reflected at the interface, and is emitted from the light exit surface 102 of the light guide 102.
b, that is, the light is emitted from the emission surface 100a of the illumination device 100 to illuminate the reflective liquid crystal display element 110.

Here, according to the scattering characteristic of the reflection electrode 114 in the reflection type liquid crystal display element 110 shown in FIG. 3, the illumination light within the incident angle of 30 ° is efficiently scattered and reflected in the front direction, so that the illumination light The angle is desirably within 30 °.

More specifically, the angle β between the reflecting portion 103b of the reflecting means 103 due to the unevenness and the exit surface 102b of the light guide 102, and the total reflection angle α at the interface between the reflecting means 103 and the air due to the unevenness. In the meantime, the illumination light as described above can be obtained by designing the shape of the unevenness so that the following equation (1), α−30 ° ≦ β ≦ α + 30 ° (1) is satisfied. .

In the first embodiment, the reflecting means 1 by unevenness is used.
03 is made of a transparent resin having a refractive index of 1.52 and forms an interface with air.
Α = sin ⁻¹ (1.0 / 1.52) = 41.8 ° (2)

Therefore, β is set to 40 ° which is almost equal to α.

It is possible to obtain illumination light having an exit angle with respect to the exit surface 102b of the light guide 102 and the exit surface 100a of the illumination device 100 substantially parallel thereto, that is, an incident angle with respect to the reflective liquid crystal display element 110 of approximately 0 °. Thus, the reflective liquid crystal display element 110 can be efficiently illuminated.

The unevenness period of the reflection means 103 and the direction of the streaks are determined in order to prevent the deterioration of the display quality due to the second light and dark fringes generated by the interference with the pixel pattern of the reflection type liquid crystal display element 110. It was determined according to FIG. That is, since the reflection type liquid crystal display element 110 has a 2.0 type delta arrangement, the reflection means 103 has a period P of 390 μm and a horizontal direction of the pixel pattern of the reflection type liquid crystal display element 110 as shown in FIG. And an angle of 14 °. This shortens the period of the second bright and dark fringes due to interference between the reflective means 103, which is composed of periodically formed irregularities, and the pixel pattern of the reflective liquid crystal display element 110, and is not recognized by an observer. The display quality of the liquid crystal display element 110 is not impaired.

Further, of the period 390 μm of the unevenness of the reflecting means 103, the length P1 of the propagation portion 103a is set to 3 on average.
The ratio (P2 / P1) of the reflection part 103b to the propagation part 103a (P2 / P1) was set to about 70 μm and the average length P2 of the reflection part 103b to 20 μm. Therefore, the observer mainly operates the display of the reflective liquid crystal display element 110 mainly for the propagation section 103.
a, and a double image generated by light reaching the observer through the reflection portion 103b can be prevented, and a good display quality can be obtained.

The anti-reflection film 104 disposed on the light exit surface 102b of the light guide 102 has the effect of reducing the surface reflection of the light guide 102 and improving the transmittance. When the display of the element 110 is observed, a bright display with a high contrast ratio can be performed. When the lighting device 100 is turned on, the reflection type liquid crystal display element 110 is used to suppress the generation of the first light and dark fringes caused by the reflecting means 103 due to the unevenness periodically formed on the opposing surface 102 c of the light guide 102. Display quality can be improved. For the same reason, it is desirable that the surface of the reflection type liquid crystal display element 110, that is, the surface of the polarization selective transmission unit 111 is also subjected to an antireflection treatment.

In the first embodiment, since the glass plate is used for the light guide 102, the warp caused by the thermal expansion of the transparent resin and the anti-reflection film 104 forming the reflection means 103 even in high and low temperature environments. Can be reduced, and the reliability of the lighting device 100 is improved. Further, by selecting a resin having high rigidity and high degree as the transparent resin forming the reflection means 103, it is possible to prevent the performance from being deteriorated due to scratches or the like.

With the illumination device 100 and the reflective liquid crystal display element 110 having the above-described configurations, a bright and high-quality image can be provided, and a highly reliable display device can be realized.

In the first embodiment, a fluorescent tube is used as a light source. However, light is uniformly applied to the incident surface of the light guide, such as an EL, an LED, or a combination of an LED and a rod-shaped light guide. Any light source may be used.

The material of the light guide 102 is not only glass but also
A transparent resin represented by an acrylic resin, a polycarbonate resin, or an epoxy resin can be used as appropriate.

The material of the reflecting means 103 is not limited to an ultraviolet curable resin, and a thermosetting resin, an acrylic resin, a polycarbonate resin, a transparent resin represented by an epoxy resin, or the like can be appropriately used. In addition, the reflection unit 103 may be configured by attaching a reflection sheet in which a number of irregularities made of a transparent resin are formed on a transparent base material to the light guide 102.

In addition to bonding an antireflection film 104 to the emission surface 102b of the light guide 102,
An antireflection layer may be directly formed on the substrate. Further, as in the reflection type liquid crystal display element 110 in the first embodiment, the polarization selective transmission unit 111 includes a polarizing plate 111a and a λ / 4 plate 111c.
If it is provided with the anti-reflection film 104
Instead, the polarized light selective transmission unit 111 may be attached to the emission surface 102b of the light guide 102.

The unevenness period of the reflection means 103 and the direction of the streaks are not limited to the above, and may vary depending on the pixel pattern of the reflection type liquid crystal display element as shown in FIGS. That is, the direction of the streaks of the unevenness formed by the reflection means 103 shown in FIG. 2 differs depending on the period, but when the pixel pattern is in a delta arrangement, as shown in FIG. ~ 25 °, and 55 ° ~ 8
It is desirable to have an angle of 0 °, and when the pixel pattern has a stripe arrangement, as shown in FIG.
It is desirable to have an angle of 75 °.

The light guide 102, the reflecting means 103,
The selection of the type of the antireflection processing 104 and the polarization selective transmission unit 111 is appropriately determined in consideration of the performance and reliability of the illumination device.

The reflection type liquid crystal display element 110 is not limited to the one having the polarization selective transmission means 111 and displaying an image by modulating the circularly polarized light, and a reflection type liquid crystal display element utilizing various modes of liquid crystal molecules is applied. can do.

(Embodiment 2) FIGS. 10 and 11 show a configuration example of a lighting device according to Embodiment 2 of the present invention and a display device using a reflective liquid crystal display device having the same.

In the second embodiment, as shown in FIGS. 10 and 11, a lighting device 200 includes a light source 201 and a light guide 20.
2. The light guide 2 comprises a low refractive index layer 204, a protective film 205, and a polarized light selective transmission unit 211.
02, the surface of the illuminating device 200 on the side from which the illumination light is emitted is defined as the emission surface 202b, and the surface facing this is the facing surface 2b.
02c. In the lighting device 200, the reflection means 20
3 is formed by forming a low-refractive-index layer 204 having a smaller refractive index than the light guide 202 on the surface of a large number of irregularities formed integrally with the light exit surface 202b of the light guide 202. A protective film 205 is further attached on the refractive index layer 204. Further, the reflection type liquid crystal display element 210
It comprises a pair of glass substrates 212a, 212b, a liquid crystal layer 213 sandwiched between them, and a reflective electrode 214 disposed on the back side thereof.

More specifically, a fluorescent tube is used for the light source 201, and polycarbonate having a refractive index of 1.58 is injection-molded for the light guide 202, and concavities and convexities serving as the reflection means 203 are integrally formed on the facing surface 202c. did.

As the low refractive index layer 204, an ultraviolet curable resin DEFENSA7702 manufactured by Dainippon Ink and Chemicals, Inc. is used.
A was applied. This UV-curable resin has a refractive index of 1.38 after curing, and has a lower refractive index than polycarbonate, which is a material of the light guide 202.

The protective film 205 has a base material of PE
A T-film 205a was applied, and a hard coat layer, an antireflection layer, and a layer 205b serving as an antifouling layer were formed on one side as shown in a partially enlarged view of FIG.

The above-mentioned ultraviolet curable resin is applied on the unevenness serving as the reflection means 203 formed on the opposing surface 202c of the light guide 202, a protective film 205 is further disposed, and ultraviolet light is irradiated from the protective film 205 side. Thus, the low refractive index layer 204 was formed, and the light guide 202 and the protective film 205 were integrated. Here, the protective film 205
Is a layer 2 which is a hard coat layer, an antireflection layer and an antifouling layer.
05b is located outside.

As shown in the partial enlarged view of FIG. 11, the polarization selective transmission means 211 includes a polarizing plate 211a and a λ / 2 plate 211.
b and the λ / 4 plate 211c are bonded in this order via an adhesive layer, and the polarizing plate 211a is bonded to the emission surface 202b of the light guide 202 via the adhesive layer. The light incident on the polarization selective transmission means 211 is
At 1a, only linearly polarized light is selected, the light is rotated by the λ / 2 plate 211b, and the λ / 4 plate 211c converts the linearly polarized light into circularly polarized light.

The reflection type liquid crystal display element 210 has a 2.5-type delta arrangement, the number of pixels is 280 × 220, and the pixel size is 179.5 × 168.5 μm.

Accordingly, the ambient light passing through the polarization selective transmission unit 211 or the illumination light from the illumination device 200 is received, and the amount of light reflected by the reflective electrode 214 and again passing through the polarization selective transmission unit 211 is controlled for each pixel. To display the image. Note that the reflective electrode 214 has a scattering characteristic as shown in FIG.

Next, a description will be given of the concavo-convex formed integrally with the opposing surface 202c of the light guide 202 and the reflection means 203 by the low refractive index layer 204. As shown in the partial enlarged view of FIG. 10, the unevenness includes a propagation portion 203a substantially parallel to the emission surface 202b of the light guide 202, and a reflection portion 203b inclined with respect to the emission surface 202b. Therefore, the light from the light source 201 enters the light guide 202 via the incident surface 202a, and the light that reaches the reflecting portion 203b is the low refractive index layer 20b.
The light exit surface 202 of the light guide 202 is totally reflected at the interface with
b, and illuminates the reflective liquid crystal display element 210 by emitting from the emission surface 200a of the illumination device 200.

The reflection electrode 21 of the reflection type liquid crystal display element 210
Reference numeral 4 efficiently scatters and reflects illumination light having an incident angle of 30 ° or less in the front direction. Therefore, the angle β formed between the uneven reflecting portion 203b of the reflecting means 203 and the emission surface 202b of the light guide 202, the unevenness formed on the facing surface 202c and the low refractive index layer 2
And the total reflection angle α at the interface of the irregularities of the reflection means 203 constituted by the reflection means 04 and the following equation (1): α−30 ° ≦ β ≦ α + 30 ° (1) It is desirable to design the shape of the unevenness so that the incident angle of the illumination light to the reflective liquid crystal display element 210 is within 30 °.

In Embodiment 2, the unevenness of the reflecting means 203 is made of polycarbonate having a refractive index of 1.58, and the low refractive index layer 204 has a refractive index of 1.38. Equation (3), α = sin ⁻¹ (1.38 / 1.58) = 60.9 ° (3)

Therefore, β was set to 60 ° which is almost equal to α.

In this case, the emission surface 202 of the light guide 202
b and the exit surface 20 of the illumination device 200 substantially parallel thereto
Illumination light having an emission angle with respect to 0a, that is, an incident angle with respect to the reflective liquid crystal display element 210 of approximately 0 ° can be obtained, and the reflective liquid crystal display element 210 can be efficiently illuminated.

The irregularity period of the reflecting means 203 and the direction of the streaks formed were suitable for the 2.5-type delta arrangement which is the specification of the reflective liquid crystal display element 210 according to FIG.
Specifically, as shown in FIG.
Thus, the reflective liquid crystal display element 210 was formed so as to form an angle of 14 ° with the horizontal direction of the pixel pattern. This allows
Reflecting means 203 comprising irregularities periodically formed on opposing surface 202c of light guide 202 and reflective liquid crystal display element 210
Since the period of the second light and dark fringes due to the interference with the pixel pattern is shortened, the second light and dark fringes are not recognized by the observer and the display quality of the reflective liquid crystal display element 210 is not impaired.

Further, the irregularity period 3 as the reflection means 203
In 90 μm, the length P1 of the propagation portion 203a is 37 on average.
Assuming that the length P2 of the reflecting portion 203b is 0 μm and the average length P2 of the reflecting portion 203b is 20 μm, the ratio (P
2 / P1) was set to about 0.05. Therefore, the image of the reflection type liquid crystal display element 210 was not observed as a double image, and good display quality was obtained.

The reflecting means 203 is constituted by forming a low refractive index layer 204 on the surface of a large number of irregularities integrally formed on the facing surface 202c of the light guide 202. Since the protective film 205 is further adhered to the surface, it is possible to prevent the reflection means 203 from being damaged or deteriorated. Also, the protective film 205
Since a hard coat layer and an antifouling layer are formed on the surface of the protective film 205, it is possible to prevent the protective film 205 from being damaged or stained. Therefore, it is very effective in maintaining the performance of the lighting device 200. Further, the antireflection layer can reduce the amount of light reflected from the surroundings by the illumination means 200 and increase the amount of light incident on the reflective liquid crystal display element 210, so that a bright display with a good contrast ratio can be performed. it can.

The polarized light selective transmission means 211 bonded to the light exit surface 202b of the light guide 202 is constituted by the polarizing plate 211a, the λ / 2 plate 211b, and the λ / 4 plate 211c as described above. Therefore, the polarization selective transmission means 21
The circularly polarized light that has passed through 1 is reflected by the polarization selective transmission means 211 and the surface of the glass substrate 212a of the reflection type liquid crystal display element 210, the rotation direction is reversed, and again enters the polarization selective transmission means 211 and is absorbed. You. That is, a decrease in the display contrast of the reflective liquid crystal display element 210 due to the surface reflection of the polarization selective transmission unit 211 and the glass substrate 212a is solved. Further, an anti-reflection layer may be disposed on the surfaces of the polarization selective transmission means 211 and the glass substrate 212a. In this case, the amount of light incident on the reflective liquid crystal display element 210 increases as the surface reflection decreases. Thus, a bright display can be performed.

With the illumination device and the reflective liquid crystal display element having the above-described structure, a bright image with good display quality can be provided.
A highly reliable display device was realized.

In the second embodiment, a fluorescent tube is used as the light source 201. However, other light sources such as an EL, an LED, and a combination of an LED and a rod-shaped light guide may be uniformly applied to the incident surface 202a of the light guide 202. Any light source may be used as long as it irradiates light.

As the material of the light guide 202, besides glass, an acrylic resin, a polycarbonate resin, a transparent resin represented by an epoxy resin, or the like can be appropriately used.

The unevenness in the reflecting means 203 is
2 may be formed separately from the light guide 202 using a transparent resin or the like. Further, a reflection sheet in which a large number of irregularities made of a transparent resin are formed on a transparent substrate is used as a light guide 2.
02 may be bonded.

An anti-reflection layer may be disposed on the light exit surface 202b of the light guide 202, in addition to the polarization selective transmission means 211. In this case, it is desirable that an anti-reflection layer is also provided on the surface of the reflection type liquid crystal display element 210.

The direction of the streaks and the period of the unevenness of the reflecting means 203 is not limited to the above, and varies depending on the pixel pattern of the reflective liquid crystal display element 210 as shown in FIGS.

The reflection type liquid crystal display element 210 is not limited to one that displays an image by modulating circularly polarized light by using the polarization selective transmission means 211, and a reflection type liquid crystal display element utilizing various modes of liquid crystal molecules. Can be applied.

Lighting device 200 and reflective liquid crystal display element 2
The selection of the type of each means that constitutes 10 is determined in consideration of the performance and reliability of the display device.

(Embodiment 3) FIGS. 12 and 13 show an example of the configuration of an illuminating device according to Embodiment 3 of the present invention and a display device using a reflective liquid crystal display device having the same.

In the third embodiment, as shown in FIGS. 12 and 13, a lighting device 300 includes a light source 301 and a light guide 30.
2 and a reflection sheet 303. The reflection type liquid crystal display element 310 includes a polarization selective transmission unit 311, a pair of glass substrates 312a and 312b, a liquid crystal layer 313 sandwiched therebetween, and a reflection electrode 314 disposed on the back side thereof.

More specifically, a fluorescent tube was used as the light source 301 and the light guide 302 was a touch panel. The touch panel is an input system that detects the position of the touch panel when the surface is pressed with a touch pen 320 or the like, and is mounted on a portable information terminal or the like. Here, in the light guide 302, the lighting device 30
The surface on the side from which the 0 illumination light is emitted is referred to as an emission surface 302b, and the surface facing this is referred to as an opposing surface 302c.

As shown in a partially enlarged view of FIG. 12, the reflection sheet 303 is a member 30 having projections and depressions serving as reflection means.
The low refractive index layer 307 is formed on the irregularities of No. 6 and is sandwiched between a base material 304 and a base material 305. The base material 305 is the light guide 302 on the back surface of the touch panel. It is bonded to the surface 302b via an adhesive layer.

Specifically, the PET film 3 as the base material
A member 306 having a large number of irregularities is arranged by molding polycarbonate having a refractive index of 1.58 on 04a. Further, the low refractive index layer 307 is provided with an ultraviolet curable resin DEFENSA7 manufactured by Dainippon Ink and Chemicals, Inc.
702A is applied, applied on the unevenness of the member 306, the PET film 305 as the base material is again placed, and the ultraviolet ray is irradiated to cure the ultraviolet ray cured resin. here,
The refractive index of the ultraviolet curable resin after curing is 1.38.
The substrate 304 is made of the member 30 of the PET film 304a.
An anti-reflection layer 304b is formed in advance on a surface on which 6 is not formed.

The reflection type liquid crystal display element 310 has a 3.8-type QVGA, that is, a stripe array having 960 × 2 pixels.
40, and the pixel size is 81 × 234.5 μm.

As shown in a partially enlarged view of FIG. 13, the polarization selective transmission means 311 provided in the reflection type liquid crystal display element 310 includes a polarizing plate 311a, a λ / 2 plate 311b, and a λ / 4.
The plate 311c is bonded in this order via the adhesive layer,
A λ / 4 plate 311c is bonded to a glass substrate 312a.

Therefore, the reflection type liquid crystal display element 310 receives the circularly polarized light which has passed through the polarization selective transmission means 311 out of the ambient light or the illumination light from the illumination device 300, and
An image is displayed by controlling the amount of light reflected at 4 and again passing through the polarization selective transmission unit 311 for each pixel. The reflective electrode 314 has a scattering characteristic as shown in FIG.

Next, a description will be given of the uneven shape of the member 306 serving as the reflection means formed on the reflection sheet 303. The unevenness is caused by the propagation portion 306a substantially parallel to the emission surface 302b of the light guide 302 and the reflection portion 30 inclined with respect to the emission surface 302b.
6b. As described above, since the reflection sheet 303 is bonded to the emission surface 302 b of the light guide 302, light from the light source 301 enters the light guide 302 via the incident surface 302 a to form the irregularities 306. Reflector 306
b, is totally reflected at the interface with the low-refractive-index layer 307, exits from the exit surface 300a of the illumination device 300, and illuminates the reflective liquid crystal display element 310.

The reflection electrode 31 of the reflection type liquid crystal display element 310
Reference numeral 4 efficiently scatters and reflects illumination light having an incident angle of 30 ° or less in the front direction. Therefore, the uneven reflecting portion 30 of the member 306
6b and the angle β formed by the light exit surface 302b of the light guide 302
And the total reflection angle α at the interface between the low refractive index layer 307 and the unevenness of the member 306, the following equation (1), α−30 ° ≦ β ≦ α + 30 ° (1) is established. It is desirable to design the shape of the concavities and convexities so that the incident angle of the illumination light to the reflective liquid crystal display element 310 is within 30 °.

In Embodiment 3, the unevenness of the member 306 is made of polycarbonate having a refractive index of 1.58, and the low refractive index layer 307 has a refractive index of 1.38.
Is given by the following equation (4): α = sin ⁻¹ (1.38 / 1.58) = 60.9 ° (4)

Therefore, β was set to 60 ° which is almost equal to α.

In this case, the light exit surface 302 of the light guide 302
b, or the exit surface 30 of the illumination device 300 substantially parallel thereto
Illumination light having an emission angle with respect to 0a, that is, an incident angle with respect to the reflective liquid crystal display element 310 of approximately 0 ° can be obtained, and the reflective liquid crystal display element 310 can be efficiently illuminated.

The uneven period of the member 306 and the direction of the formed streaks were adapted to the 3.8-type QVGA which is the specification of the reflective liquid crystal display element 310 according to FIG. Specifically, as shown in FIG. 13, the period P is 390 μm, and the horizontal direction of the pixel pattern of the reflective liquid crystal display element 310 is
° was formed. This shortens the period of the second light and dark fringes due to interference between the reflecting means having a large number of irregularities formed periodically and the pixel pattern of the reflection type liquid crystal display element 310, so that the reflection is not recognized by the observer and the reflection is not performed. The display quality of the liquid crystal display element 310 is not impaired.

Further, of the period 390 μm of the unevenness of the member 306 as the reflection means, the average length P1 of the propagation portion 306a is 370 μm, and the average length P2 of the reflection portion 306b is 20 μm.
The reflection type liquid crystal display element 310 was designed to be uniformly illuminated by setting the length P2 to be shorter and closer to the light source and longer as the distance from the light source. At this time, the ratio of the reflection unit 306b to the propagation unit 306a (P
Since 2 / P1) is about 0.05, the image of the reflective liquid crystal display element 310 was not observed as a double image, and good display quality could be obtained.

The anti-reflection layer 304b formed on the PET film 304a which is the base material of the reflection sheet 303 reduces the surface reflection of the illumination device 300 and improves the transmittance, so that the display of the reflection type liquid crystal display element 310 is performed. It can be bright and have a good contrast ratio. For similar reasons,
It is desirable that the opposing surface 302c of the light guide 302 and the surface of the reflective liquid crystal display element 310, that is, the surface of the polarization selective transmission unit 311 are also subjected to antireflection treatment.

In the third embodiment, since the light guide and the touch panel are also used, the number of interfaces is reduced as compared with the conventional configuration in which each is made of a separate member. Since the amount of light incident on the display device increases, very bright display with a high contrast ratio can be performed. In addition, low-cost, thin, lightweight display devices,
And an information display system such as a portable information terminal.

In the third embodiment, a fluorescent tube is used as a light source. However, an EL, an LED, or a combination of an LED and a rod-shaped light guide may be used.

The light guide is not limited to a touch panel.
Glass, acrylic resin, polycarbonate resin,
A transparent resin such as an epoxy resin can be used as appropriate.

The base material 304 constituting the reflection sheet 303,
Various combinations are also possible for the 305, the member 306 having projections and depressions serving as reflection means, and the low refractive index layer 307. Further, the reflecting means formed on the base material may be directly disposed on the light emitting surface 302 b of the light guide 302 via the low refractive index layer 307.

The reflection type liquid crystal display element 3 of the reflection sheet 303
In addition to the provision of the anti-reflection layer 304b on the surface opposite to 10, the polarization selective transmission unit 311 is provided with a polarizing plate and λ / 4 like the reflection type liquid crystal display element 310 of the third embodiment. , A polarized light selective transmission unit may be attached.

The period of the unevenness as the reflection means and the direction of the formed streaks are not limited to the above, but change according to the pixel pattern of the reflection type liquid crystal display element as shown in FIGS.

The reflection type liquid crystal display element 310 is not limited to the one which includes the polarization selective transmission means 311 and displays an image by modulating the circularly polarized light, and employs a reflection type liquid crystal display element utilizing various modes of liquid crystal molecules. can do.

Lighting device 300 and reflective liquid crystal display element 3
The selection of the type of each means that constitutes 10 is determined in consideration of the performance and reliability of the display device.

(Embodiment 4) FIGS. 14 and 15 show an example of the configuration of an illuminating device according to Embodiment 4 of the present invention and a display device using a reflective liquid crystal display device having the same.

In the fourth embodiment, as shown in FIGS. 14 and 15, the illumination device 400 includes light sources 401a and 401b.
And the reflecting means 403 and the transparent flat plate 406, and the reflecting means 403 and the transparent flat plate 406 are disposed so as to be substantially parallel to each other to form the light guide space 402. Note that the transparent flat plate 406 is a touch panel. Reflective liquid crystal display element 4
10 is a polarized light selective transmission means 411, a pair of glass substrates 4
12a, 412b and the liquid crystal layer 41 sandwiched therebetween
3 and a reflective electrode 414 disposed on the back side thereof.

Specifically, fluorescent tubes are used for the light sources 401a and 401b, and they are arranged so as to face each other.

As shown in the partially enlarged view of FIG. 14, the reflecting means 403 is a prism 4 made of polycarbonate having a refractive index of 1.58 on a PET film 405 as a base material.
04 are arranged to form irregularities, and the PET film 40
5 is bonded to the reflection type liquid crystal display element 410 via an adhesive layer.

The touch panel 4 is provided above the reflection means 403.
The light guide space 402 is disposed between the two.

The reflection type liquid crystal display element 410 is a 3.8-type QVGA.

As shown in a partially enlarged view of FIG. 14, the polarization selective transmission means 411 provided in the reflection type liquid crystal display element 410 includes a polarizing plate 411a, a λ / 2 plate 411b, and a λ / 4 plate.
The plate 411c is bonded in this order via an adhesive layer, and the λ / 4 plate 411c is bonded to the glass substrate 412a.

Therefore, the reflection type liquid crystal display element 410 receives the circularly polarized light that has passed through the polarization selective transmission unit 411 out of the ambient light or the illumination light from the illumination device 400 and controls the amount of reflected light for each pixel. Use to display the image.

The reflection electrode 414 has a scattering characteristic as shown in FIG.

Next, the uneven shape of the reflecting means 403 will be described. The unevenness is formed by arranging a large number of prisms 404 on a PET film 405 serving as a base material. Each prism 404 is a transparent flat plate 406 or an emission light from which illumination light of an illumination device 400 substantially parallel thereto is emitted. A first inclined portion 404a inclined with respect to the surface 400a and a second inclined portion 404a;
404b.

Light incident on the light guide space 402 from the light source 401a propagates through the light guide space 402, reaches the prism 404, is refracted at the interface between the first inclined portion 404a and the light guide space 402, and is refracted by the second light. The light is totally reflected at the interface between the inclined portion 404b and the light guide space 402 to illuminate the reflective liquid crystal display element 410. Similarly, light that has entered the light guide space 402 from the light source 401b reaches the prism 404, and the second inclined portion 404
b, and is totally reflected by the first inclined portion 404a to illuminate the reflective liquid crystal display element 410.

The reflection electrode 41 of the reflection type liquid crystal display element 410
Reference numeral 4 efficiently scatters and reflects illumination light having an incident angle of 30 ° or less in the front direction. Therefore, the angle β formed by the first inclined portion 404a and the second inclined portion 404b of the prism 404 with the light exit surface 400a of the illumination device is determined by the prism 404 and the light guide space 4.
The angle of incidence of illumination light is designed such that the following equation (1), α-30 ° ≦ β ≦ α + 30 °, is satisfied between the total reflection angle α at the interface No. 02 and the angle α. 3
It is desirable to be within 0 °.

In the fourth embodiment, the prism 404 is made of polycarbonate having a refractive index of 1.58, and
03 has a refractive index of 1.0, the total reflection angle α is
The following equation (5) is obtained: α = asin (1.0 / 1.58) = 39.2 ° (5)

Therefore, β was set to 40 ° which is almost equal to α.

In this case, the emission surface 400 of the illumination device 400
Illumination light having an emission angle with respect to a, that is, an incident angle with respect to the reflective liquid crystal display element 410 of approximately 0 ° can be obtained, and the reflective liquid crystal display element 410 can be efficiently illuminated.

The period of the unevenness in the reflection means 403 and the direction of the streaks are determined according to FIG.
It is suitable for 3.8-type QVGA, which is a specification of 10. Specifically, as shown in FIG.
It was formed so as to make an angle of 20 ° with the horizontal direction of the pixel pattern of the reflective liquid crystal display element 310 at μm. This shortens the period of the second light and dark fringes due to the interference between the numerous irregularities formed periodically and the pixel pattern of the reflective liquid crystal display element 410, so that the reflective liquid crystal display element is not recognized by the observer. The display quality of 410 is not impaired.

Further, the period 50 of the unevenness of the reflecting means 403
0 μm, the length P of the region where no irregularities are formed
1 ′ is set to 475 μm on average, the length P2 ′ of the area where the unevenness is formed is set to 25 μm on average, and the length P2 ′ of the area where the unevenness is formed is set shorter as the light source is closer and longer as the distance from the light source. The reflection type liquid crystal display element 410 was designed to be uniformly illuminated. At this time, the ratio (P2 ′ / P1 ′) of the length of the region where the unevenness is formed to the length of the region where the unevenness is not formed is about 0.05. Was not observed as a double image, and good display quality was obtained.

In the fourth embodiment, since the light guide space 402 formed by the reflection means 403 and the touch panel 406 is used, a display device which is inexpensive and lightweight compared to the configuration using a light guide, and a portable device An information display system such as an information terminal can be realized.

In the fourth embodiment, a fluorescent tube is used as a light source. However, an EL, an LED, or a combination of an LED and a rod-shaped light guide may be used.

The reflection means 403 may be formed by, for example, a method of forming a concave and convex shape on a base material.
The reflection means may be formed by forming a large number of irregularities directly on the surface of the reflector.

The period of the unevenness of the reflecting means 403 and the direction of the streaks are not limited to the above, but change according to the pixel pattern of the reflective liquid crystal display element as shown in FIGS.

The reflection type liquid crystal display element 410 includes a polarization selective transmission unit 411, and is not limited to one that displays an image by modulating circularly polarized light, and a reflection type liquid crystal display element utilizing various modes of liquid crystal molecules is applied. can do.

Lighting device 400 and reflective liquid crystal display element 4
The selection of the type of each means that constitutes 10 is determined in consideration of the performance and reliability of the display device.

[0182]

As described above, according to the illuminating device of the present invention, it is possible to reduce the damage and deterioration of the unevenness in the reflecting means and the warpage of the light guide, thereby improving the reliability. According to the display device provided with the illumination device of the present invention, it is possible to suppress the occurrence of double images and bright and dark fringes, and to perform bright, high-contrast, high-quality display. In addition, the lighting device and the display device can be reduced in thickness, weight, and cost.

More specifically, since the light guide has a flat exit surface and a facing surface, the choice of material can be increased. For example, if glass is selected, the rigidity is higher than that of a transparent resin. Even when an anti-reflection film or the like is bonded to a plane where no light is disposed to improve the transmittance of the light guide, warpage caused by a change in temperature or the like can be reduced and reliability is increased.

Specifically, when the uneven shape is formed integrally with the light guide, the light guide is formed by using a transparent resin represented by an acrylic resin, a polycarbonate resin, an epoxy resin, or the like as the material. The body and the reflecting means can be molded simultaneously.

In the case where the uneven shape is formed separately from the light guide, the uneven shape may be formed on the emission surface or the opposing surface of the light guide in addition to acrylic resin, polycarbonate resin, epoxy resin, etc. Molding can be performed using a transparent resin such as a thermosetting resin, and the choice of materials can be increased. That is, it is possible to select a material having reliability such as hardness and chemical resistance in the uneven shape.

In the case where the reflecting means has a structure in which a member having irregularities and a refractive index layer having a different refractive index, preferably a low refractive index, are formed on the irregularities, the illuminating device may be damaged or deteriorated due to irregularities. Can be prevented from deteriorating.

In the case where the reflection means uses a reflection sheet, the transmittance of the light guide can be improved by bonding the reflection sheet and the antireflection film to the emission surface and the opposite surface. In addition, the two can be balanced to further reduce the warpage of the light guide caused by a temperature change or the like.

In the case where the reflecting means is disposed on the opposite surface of the light guide, an antifouling film (water repellent layer), a hard coat layer and the like are formed on the surface of the low refractive index layer, so that the surface of the lighting device can be formed. Reliability can be improved, and the reflectance of the surface can be reduced by forming the antireflection layer.

In the case where the reflecting means is disposed on the light emitting surface of the light guide, the unevenness is protected by the light guide, so that the reliability of the reflecting means can be improved.

In the lighting device using the light guide space constituted by the reflection means and the transparent flat plate, the weight of the display device can be further reduced.

When a touch panel is added as an input device to a display device including a reflective liquid crystal display element and a lighting device, the light guide and the touch panel may be used. In this case, the display device, the portable information terminal, and the like can be reduced in thickness, weight, and cost.

If the uneven shape of the reflecting means is a prism-like shape composed of a propagation portion substantially parallel to the light exit surface of the light guide and an inclined reflecting portion, an air layer having a lower refractive index than the unevenness can be obtained. When the interface is formed with the refractive index layer, total reflection occurs, and illumination light can be emitted more efficiently.

Assuming that the total reflection angle due to the difference in the refractive index at the interface of the reflecting portion is α, the angle β formed by the reflecting portion with respect to the light exit surface of the light guide or the transparent flat plate is α.
However, if the relationship of the above formula (1) is satisfied, it is possible to efficiently illuminate the reflection type liquid crystal display element, so that a display device which is bright, has a good contrast ratio, and can perform high-quality display is obtained. Can be

Further, the ratio of the length of the reflecting portion to the length of the propagation portion of the unevenness as the reflecting means (P2 / P1), or the ratio of the area where the unevenness is formed and the area where the unevenness is not formed (P2 ′ / When P1 ′) satisfies the predetermined relationship, it is possible to suppress the occurrence of double images and bright and dark stripes of the reflective liquid crystal display element.

In addition, by arranging the polarization selecting means of the reflection type liquid crystal display element on the emission surface of the illumination device, it is possible to perform bright, high-contrast, high-quality display without generating bright and dark stripes. A display device is obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a display device including a lighting device and a reflective liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a display device using a lighting device and a reflective liquid crystal display element according to Embodiment 1 of the present invention.

FIG. 3 is a diagram showing the scattered reflection characteristics of a reflection electrode used in a reflection type liquid crystal display element.

FIG. 4 is a diagram illustrating a relationship between a lighting device in which a second light and dark fringe does not occur and a reflective liquid crystal display element in a delta arrangement.

FIG. 5 is a diagram illustrating a relationship between a lighting device in which a second bright and dark fringe does not occur and a reflective liquid crystal display element in a stripe arrangement.

FIG. 6 is a first diagram illustrating an optimal shape of a reflecting means in the lighting device of the present invention.

FIG. 7 is a second diagram illustrating an optimal shape of the reflection means in the lighting device of the present invention.

FIG. 8 is a diagram illustrating a method for evaluating a double image in display of a reflective liquid crystal display element by the illumination device of the present invention.

FIG. 9 shows the degree of a double image in the display of the illumination device and the reflection type liquid crystal display element of the present invention, the ratio of the reflection part and the propagation part (P2 / P1) of the unevenness, and the area where the unevenness is formed. FIG. 9 is a diagram showing the relationship of the ratio of unoccupied regions (P2 ′ / P1 ′).

FIG. 10 is a cross-sectional view illustrating a display device including a lighting device and a reflective liquid crystal display element according to a second embodiment of the present invention.

FIG. 11 is a perspective view showing a display device including a lighting device and a reflective liquid crystal display device according to a second embodiment of the present invention.

FIG. 12 is a sectional view showing a lighting device and a display device using a reflective liquid crystal display element according to a third embodiment of the present invention.

FIG. 13 is a perspective view showing a display device using a lighting device and a reflective liquid crystal display device according to a third embodiment of the present invention.

FIG. 14 is a cross-sectional view illustrating a display device including a lighting device and a reflective liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 15 is a perspective view showing a display device including a lighting device and a reflective liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 16 is a diagram illustrating a configuration example of a reflective liquid crystal display element.

17A and 17B are diagrams showing an arrangement pattern of pixels of a reflection type liquid crystal display element, wherein FIG. 17A shows a case of a delta arrangement, and FIG.
Shows a case of a stripe arrangement.

FIG. 18 is a diagram illustrating a configuration example of a front light that is a conventional lighting device.

[Description of Signs] 30, 101, 201, 301, 401a, 401b,
911 Light source 31, 102, 202, 302, 912 Light guide 32, 110, 210, 310, 410, 920 Reflective liquid crystal display element 33, 111, 211, 311, 411, 921 Polarization selective transmission means 34a, 34b, 112a , 112b, 212a, 21
2b, 312a, 312b, 412a, 412b, 92
2a, 922b Glass substrate 35, 113, 213, 313, 413, 923 Liquid crystal layer 36, 114, 214, 314, 414, 924 Reflecting electrode 37 Observer 100, 910 Illumination device (front light) 102a, 202a, 302a, 912a Incident surfaces 100a, 102b, 200a, 202b, 302b,
912b Outgoing surface 102c, 202c, 302c, 912c Opposing surface 103, 203, 913 Reflecting means (unevenness) 103a, 203a, 306a, 913a Propagating portion 103b, 203b, 306b, 913b Reflecting portion 104 Anti-reflection film 111a, 211a, 311a, 411a Polarizing plate 111b, 211b, 311b, 411b λ / 4 plate 111c, 211c, 311c, 411c λ / 2 plate 200, 300, 400 Lighting device 204, 307 Low refractive index layer 205 Protective film 205a Protective film base material 205b Hard Coat layer, antireflection layer, antifouling layer 303, 403 Reflection sheet (reflection means) 304, 305 Base of reflection sheet 304a PET film 304b Antireflection layer 306 Member having irregularities 402 Light guide space 404 Prism 4 04a first inclined portion 404b second inclined portion 405 base of reflection sheet 406 transparent flat plate (touch panel) 914 optical compensator 915 compensation unevenness

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Takeshi Ebi 22-22, Nagaike-cho, Abeno-ku, Osaka City, Osaka F-term (reference) 2H091 FA02Y FA08X FA08Z FA11Z FA14Z FA21Z FA23Z FA37Z FA42Z FA44Z FA45Z FB04 FC02 FC14 FC23 FD15 GA02 KA01 KA10 LA11 LA17 LA21

Claims (8)

[Claims] 1. A light guide comprising: a light source; an incident surface on which light from the light source is incident; an exit surface substantially perpendicular to the incident surface, from which illumination light exits; and a facing surface facing the exit surface. And a reflecting means formed or arranged separately from the light guide on an emission surface or an opposing surface of the light guide. The light source enters the light guide through the incident surface of the light guide to guide the light. An illuminating device that emits illumination light by reflecting light propagating inside an optical body by the reflection means. 2. A light guide space is formed by arranging a transparent flat plate and a reflection means to face each other, and a light source is arranged on an end face of the light guide space. And an illumination device that reflects the light propagating through the light guide space by the reflection unit and emits illumination light. 3. The illuminating device according to claim 1, wherein the reflecting means reflects light by a difference in refractive index between interfaces of the uneven shape. 4. The reflection means comprises a combination of two members having different refractive indices, wherein an interface between the two members has an uneven shape, and reflects light by a difference in refractive index between the interfaces. The lighting device according to claim 1. 5. The light guide according to claim 1, wherein the projections and depressions of the reflection means have a prism shape, and have a propagation section and a reflection section inclined substantially parallel to an emission surface of the light guide. The illumination device according to claim 1, 3 or 4, wherein the light that enters through the incident surface and propagates mainly through the propagation portion is reflected by the reflection portion to emit illumination light. 6. An uneven shape of the reflection means is prism-shaped, and has a refraction part and a reflection part which are inclined with respect to the transparent flat plate, and transmits light incident on the light guide space from the light source. The illumination device according to claim 2, 3 or 4, wherein the illumination light is refracted at an interface of the refraction portion and reflected by the reflection portion to emit illumination light. 7. When the concave and convex shape of said reflecting means is such that a total reflection angle due to a difference in refractive index at an interface of said reflecting portion is α, said reflecting portion is positioned with respect to an emission surface of said light guide or said transparent flat plate. The lighting device according to claim 5, wherein the angle β satisfying the relationship satisfies the following equation (1): α−30 ° ≦ β ≦ α + 30 ° (1). 8. An illuminating device according to claim 1, wherein the illuminating device receives illumination light from the illuminating device, and controls the reflectance for each pixel to display an image. A display device provided with an element.