JPH10188636A - Electronic apparatus, portable telephone, watch camera, and data terminal apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of bright lines caused by regular reflection and dissolve the luminance irregularities caused by the one-dimensional arrangement of a lug pattern by forming a front light with a light guide plate made of a transparent flat plate formed with multiple dot-like diffused shape and dot-like light sources arranged on the end face. SOLUTION: One or multiple dot-like light sources 2 are arranged on the end face of a transparent light guide plate 1, and lugs 10 are provided on one face. The faces of the lugs 10 are formed with nearly parallel faces (bottom faces 4) with light outgoing faces 3 and nearly perpendicular faces (side faces 5). Multiple dot-like light diffusion sections are provided on the lower face of the light guide plate 1, they are formed into a nearly cylindrical shape like the lugs 10, luminescent spots are uniformly distributed in the surface of the light guide plate 1, and the occurrence of linear strong luminescent lines impairing the visibility of a display can be prevented. Uniform visibility is obtained regardless of the observation position. A bright reflection type display is obtained in the daytime, and the utilization efficiency of the electric power required for illumination is increased at night to save electric power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device such as a cellular phone device, a clock, a camera, and a data terminal device having a reflective liquid crystal display device mounted on a display unit, and more particularly to an illumination method in a dark environment.

[0002]

2. Description of the Related Art A reflection type liquid crystal display device has been greatly developed and spread as a display device which operates with a small amount of electric power, as an information transmission medium for a watch, a calculator, a mobile phone, a small information device, various home appliances, and the like. . Various display modes have been invented, such as a TN type (twisted nematic), an STN type (super twisted nematic), and a ferroelectric type.

FIG. 3 is a cross-sectional view of a reflective liquid crystal display device that is generally used at present. Reference numerals 21 and 22 respectively have transparent electrode films 26, 27 and 28 on the upper and lower substrates facing each other. Reference numeral 29 denotes a liquid crystal layer inserted between the upper and lower substrates 21 and 22. By selecting a liquid crystal material and a liquid crystal molecular arrangement of the liquid crystal layer 29, the above-described TN type, ST
Display modes such as N type and ferroelectric type can be arbitrarily selected.
The basic sectional structure of the reflective liquid crystal display device is as shown in FIG. 23 is an upper polarizing plate, 24 is a lower polarizing plate, and 25 is a reflecting plate. Next, the basic operation will be described. The incident lights 30 and 31 are polarized by passing through the upper polarizing plate 23. Thereafter, a voltage application unit (here, the transparent electrode 2)
6 and a transparent electrode 28) and a voltage non-applied portion (here, a region sandwiched between the transparent electrode 27 and the transparent electrode 28) have optical properties in the liquid crystal layer. As a result, the respective polarization axes of the respective polarized lights 30 and 31 passing through the liquid crystal layer 29 take directions substantially orthogonal to each other and reach the lower polarizing plate 24. Here, if the direction of the polarization axis of the lower polarizing plate 24 is optimally set, as shown in FIG.
0 is absorbed by the lower polarizing plate 24 to give a black display appearance, and the incident light 31 passes through the lower polarizing plate 24 and is reflected by the reflecting plate 25, passes through the lower polarizing plate 24 again, and the liquid crystal layer 29, the upper polarized light. The light is emitted outside through the plate 23. Therefore, the display appearance of the voltage non-applied portion is white (specifically, gray). The above operation is common to the TN type, STN type, and ferroelectric type liquid crystal layers. The detailed operation principle is described in Document 1 (“Liquid Crystal Device Handbook”, edited by the 142nd Committee of the Japan Society for the Promotion of Science, published by Nikkan Kogyo Shimbun, pages 303 to 386). Here, an important problem as a reflection type liquid crystal display device mounted on a portable electronic device is how to realize a bright reflection type display device.

Further, as described above, the reflection type liquid crystal display device is widely used for a display unit such as a clock, a mobile phone, a data terminal device, a camera and the like, and these electronic devices can sufficiently perform a display function at night. Thus, there are many electronic devices that require a lighting device. In order to satisfy the above requirements, the conventional reflective liquid crystal display device shown in FIG. 3 uses a semi-transmissive reflective plate 68 as a reflective plate of the liquid crystal display device 65 like the transflective liquid crystal display device shown in FIG. I have. The transflective reflector 68
There are many types of products that are commercially available but generally reflect 80% of light and transmit 10% of light (the remaining 10% is light absorption loss in the reflective layer). .
Therefore, in a bright environment, 80% of the light incident from the top surface
Is reflected to function as a reflective liquid crystal display device. On the other hand, in a dark environment, the display is read by irradiating light from the light emitting body 70 disposed on the back surface of the liquid crystal display device 65 from the back surface through the semi-transmissive reflection plate 68 having a transmittance of 10%. Here, the luminous body 70 arranged on the back surface corresponds to FIG.
As shown in FIG. 3, the light guide plate 66 is composed of at least a light guide plate 66 and a light emitting source 67 provided at an end of the light guide plate 66 and a reflecting plate 69 also provided on the lower surface. A luminous body that is introduced into the light plate 66 and is scattered by light scattering nuclei provided on the light guide plate 66 and emits light from the upper surface of the light guide plate 66 is generally used. (Electroluminescence) Light-emitting materials are often used in watches and the like.

As described above, in the conventional reflection type liquid crystal display device, since the transflective type reflection plate is used as the lower polarizing plate to enable nighttime illumination, the brightness of the reflection type display is sacrificed. I've been On the other hand, night illumination is also illuminated from the back surface through the transflective reflector, so that only 10% or less of the amount of light emitted from the illumination light source can contribute to the illumination, resulting in a large waste of energy. In particular, a battery is used as an energy source. There has been a problem of shortening the battery life of electronic devices such as mobile phone devices, watches, cameras, data terminal devices, and the like. Then, Japanese Patent Application Laid-Open No. 6-28939
The use of a front light as disclosed in Japanese Patent Application Laid-Open No. 6-324331 or JP-A-6-324331, that is, an illuminating device arranged on the upper surface of a liquid crystal display device has no transmissivity instead of a semi-transmissive reflector, that is, impairs the reflection performance. Since a reflector having no problem can be used, the brightness of the reflective display is hardly impaired, and it is an effective means for illuminating the display section with low power at night.

On the other hand, the above-mentioned mobile phone, clock, camera,
LE operating at low power as a light source of a liquid crystal display device used in a small portable electronic device such as a data terminal.
Point light sources such as D (light emitting diode) and miniature light bulbs are widely used. They do not require a special mechanism such as a step-up device, are lightweight and compact, and are superior in safety because they do not use high frequency and high voltage. No. In addition, power control is easy, and it can easily cope with low power consumption applications.
In particular, LEDs have a semi-permanent life, and recently, red, green, blue, a mixture thereof, and white have become possible. Using a light bulb shortens the life but is inexpensive,
It has the potential to be easily exchanged. For the above reasons, the light source for illuminating the display of the small portable device described above is L
Point light sources such as EDs and miniature bulbs are most preferred.

In view of the above, the above-mentioned Japanese Patent Application Laid-Open No. 6-289391
2 (a) and 2 (b) of the front light shown in FIGS. 2 (a) and 2 (b) are partially sectional views, and (b) is a perspective view of the whole. ) And a point light source such as an LED or a miniature light bulb as a light source, the intersection of the light emitting surface 13 of the light guide plate 11 and the side surface 15 of the projection 12 has a minute curved surface due to manufacturing. It was found that some reflected light 19c leaked to the light exit surface 17 side (observer side) and was observed as a bright spot for the observer. As shown in FIG.
2 is a rib, and if the intersection is a straight line, the point light source 14, the bright spot, and the observer are arranged on the same plane, and the observer is given a specific position on the light guide plate. Are bright spots, and the bright spots appear at the bases of the respective rib-shaped protrusions, and it looks as if a continuous bright line is generated as a whole, and the bright line also moves as the observer moves. It has been found that these significantly reduce the visibility of the reflection type liquid crystal display device, which is an object to be illuminated disposed under the front light.

[0008]

SUMMARY OF THE INVENTION As described above, the present invention relates to the illumination of electronic equipment using a reflective liquid crystal display device as a display unit, for example, portable telephone equipment, clocks, cameras, and data terminal equipment. As means, a front light is used, and as a light emitting source thereof, an LED, a miniature lamp, etc., such as a point light source, is used to prevent the generation of the bright line due to regular reflection at a root portion of a rib shape, which is generated. Is a point light source, aims to solve the problem of eliminating uneven brightness caused by a one-dimensional array of projection patterns, provides an optimal front light with a point light source, and can save power. It is an object of the present invention to provide various electronic devices such as a mobile phone device, a clock, a camera, and a data terminal device having a liquid crystal display device having high-quality lighting means in a display portion. .

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, in an electronic device, a cellular phone device, a clock, a camera, and a data terminal device using the lighting means according to the present invention, (1) at least lighting In an electronic apparatus using a reflection type liquid crystal display device having a front light on an upper surface as a display unit, the front light is a light guide made of a transparent flat plate having a plurality of dot-like light diffusion shapes formed on a surface. It is characterized by comprising at least a light plate and a point light source arranged on the end face.

(2) The light diffusion shape is characterized in that it is distributed relatively sparsely in the vicinity of the light source and continuously and densely as the distance from the light source increases.

(3) On the surface of the light guide plate facing the object to be illuminated, columnar projections are provided as the light diffusion shape.

(4) The light guide plate is characterized in that a concave shape is provided as the light diffusion shape on a surface different from the surface facing the object to be illuminated.

(5) The light guide plate is characterized in that a convex shape is provided as the light diffusion shape on a surface different from a surface facing the object to be illuminated.

(6) A light diffusing member is provided as the light diffusing shape on a surface of the light guide plate different from the surface facing the object to be illuminated.

(7) The diameter or the maximum diameter of the light diffusion shape is not less than 5 μm and not more than 300 μm.

(8) The light diffusion shape has a diameter or a maximum diameter of 10 μm or more and 100 μm or less.

(9) A light emitting diode (LED) is used as the point light source.

(10) A light bulb is used as the point light source.

(11) A transparent plate or a transparent sheet is provided so as to face a surface of the light guide plate different from the surface facing the object to be illuminated.

(12) The electronic device according to any one of (1) to (11) is a portable telephone device.

(13) The electronic device according to any one of (1) to (11) is a timepiece.

(14) The electronic device according to any one of (1) to (11) is a camera.

(15) The electronic device according to any one of (1) to (11) is a data terminal device.

[0024]

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

(Embodiment 1) FIGS. 1A and 1B are a cross-sectional view and an external view of a front light according to the present invention. One or a plurality of point light sources 2 are provided on an end face of a transparent light guide plate 1. Place. As shown in FIG. 1B, the light guide plate 1 is provided with a projection 10 on one surface of a transparent plate, and each surface of the projection 10 is substantially perpendicular to a surface (bottom surface 4) substantially parallel to the light emitting surface 3. It is composed of a surface (side surface 5). The light guide plate 1 has a refractive index of about 1.4.
It is formed of the above transparent material. The light beam from the point light source 2 enters the end face 8 as shown by the light rays 9a and 9b, and then undergoes total reflection in the light guide plate 1 to repeat the side face 5 of the projection 10.
Since the light is emitted only from the illumination device, a large amount of light is emitted from the lower surface of the illuminating device, and the illuminated object 6 (here, the reflection type liquid crystal display device as described above. Point) can be illuminated effectively.

As the transparent material forming the light guide plate 1, a transparent resin such as an acrylic resin, a polycarbonate resin or an amorphous polyolefin resin, an inorganic transparent material such as a glass, or a composite thereof is used. It is formed by a method such as joining a film or a resin layer on a resin, a photocurable resin, etching, a transparent resin or a glass flat plate.

As the point light source 2, a light emitting diode (LE)
D), a light bulb or the like is used. As described above, they do not require a special mechanism such as a booster, are lightweight and compact, and are superior in safety because they do not use high frequency and high voltage, as compared with fluorescent tubes that have been used conventionally. It does not become a source of radio interference. In addition, power control is easy, and it can easily cope with low power consumption applications. Especially LED
Has a semi-permanent lifespan, and recently has a red color.
Green, blue, mixed colors, and white are also possible. When a light bulb is used, its life is shortened, but it is inexpensive and has the possibility of being easily replaced.

With the above arrangement, the present illumination device is arranged in front of the object to be illuminated 6, and when the external light is sufficiently bright, the illumination is turned off and the object to be illuminated 6 is observed.
It has been confirmed that the external appearance is the same as that of a transparent flat plate placed on the object 6 and has little effect on the display performance of the object 6). Can be turned on to observe the object to be illuminated 6 to realize a part-time illumination. Further, according to the present embodiment,
When a plurality of dot-shaped light diffusing portions are provided on the lower surface of the light guide plate 1 and the shape thereof is substantially columnar like the protrusions 10, the bright spots which have been the problem described above are uniformly distributed in the surface of the light guide plate 1. It was observed that a strong linear bright line which impairs the visibility of the display described above did not occur. Furthermore, it was confirmed that uniform visibility was obtained regardless of the observation position.

An electronic device having a liquid crystal display device having the above-described front light in the display section can provide a bright reflective display in the daytime as compared with a conventional electronic device having a liquid crystal display device using a transflective reflector. At the same time, at nighttime, the efficiency of using the power required for illumination is high and the power consumption can be reduced, and an electronic device with uniform and bright display illumination without generation of a specific bright line has been realized.

Since the wavelength of visible light is about 380 nm to 700 nm, the diameter of the bottom surface 4 is 5 μm because the influence of diffraction does not occur.
It is necessary that the thickness is not less than about 300 μm, and the projection 10 has such a size that it does not matter to the naked eye. In addition to the contents described above, the size of the protrusion is desirably about 10 μm or more and 100 μm or less for convenience in manufacturing. In addition, the height and width of the projection 10 (the diameter is approximately cylindrical).
In the light guide plate 11, the light ray in the light guide plate 11 has an elevation angle in the plane direction (the angle formed between the light ray and the plane (the plane of 3 or 7 in FIG. 1A)) of 45 degrees or less, and is 1: 1. Less than, actually 2
Since light rays of 0 degrees or less occupy 90% or more, sufficient performance is exhibited up to about 1: 2.

(Embodiment 2) Referring to FIG.
One has a concave shape 812a on the side of the light exit surface 817. The concave shape 812a has an arbitrary size and shape (polygonal pyramid, cone, elliptical sphere, sphere, etc.), and converts a light beam reaching the concave shape 812a into a light beam having a large elevation angle with respect to the plane of the light guide plate 811. However, it has been found that good characteristics are exhibited by forming a substantially spherical surface having a central angle of 90 degrees or less.

The light beam guided from the point light source 82 to the light guide plate 811 guides the light by repeating total reflection within the light guide plate 811, and the concave shape 812 is formed on the light exit surface 817 of the light guide plate 811.
a is provided, and the luminous flux arriving there is
The light is converted into a light beam having a large elevation angle with respect to one plane, and can be emitted from the light emitting surface 813. By arranging the illuminated object 86 on the light exit surface 813 side of the light guide plate 811, this configuration functions as a planar illumination. In addition, anti-light emitting surface 8
Since the surface other than the concave shape on the 17th side is parallel to the light emitting surface 813 side, it has a vertical ray transmission function of transmitting light rays from a direction intersecting the flat plate (that is, light from the upper and lower parts). Also have. Thus, when the point light source 82 is turned off in a bright environment and the liquid crystal display is observed by external light, the light guide plate 811 looks almost like a transparent flat plate and does not particularly deteriorate the display appearance.

These concave shapes 812a can be set at an arbitrary area ratio with respect to the area of the illumination unit. However, by increasing the area ratio of the concave shape 812a,
The efficiency of illumination can be increased, but the proportion of vertically transmitted light is reduced, and the visibility of the display is reduced. Actually 5
It is not realistic to set the area ratio to more than 0%, and it is appropriate to set the area ratio to about 10% as part-time illumination in darkness. In addition, when the density is adjusted for uniformity of the illumination luminance as described above, the area ratio of the vertical transmission portion is about 80 to 90% if the density is about 10%. Can not be felt.

The size (diameter or maximum diameter) of the concave shape 812a is such that the wavelength of visible light is approximately 380 nm to 700 n.
m, it is necessary to have a thickness of about 5 μm or more to prevent the influence of diffraction from occurring.
Since the size of the portion a is so small that it is not noticeable by naked eyes, it is preferable that the size is approximately 300 μm or less. In addition to the above contents, the size of the concave shape is about 10 μm or more for convenience in manufacturing.
It is desirably not more than 00 μm.

Also in this embodiment, the bright spots, which are the above-mentioned problem, are uniformly distributed in the plane of the light guide plate 811, and the above-mentioned problem, which is a linear strong bright line which impairs the visibility of the display, is generated. Not observed. Furthermore, regardless of the observation position,
It was confirmed that uniform visibility was obtained. In particular, in this embodiment, it is recognized that the incident angle of the emitted light beam to the irradiation object 86 is closer to the vertical than in the case of the light guide plate shown in the embodiment 1, and the illumination efficiency is further improved. Was.

An electronic device having a liquid crystal display device having the above-described front light in a display section can provide a bright reflective display in the daytime as compared with an electronic device having a liquid crystal display device using a conventional transflective reflector. At the same time, it is possible to realize an electronic device that requires less power for illumination at night and has uniform and bright display illumination without generation of a specific bright line. Further, brighter illumination than that of Example 1 was obtained.

Embodiment 3 In FIG. 5, a light guide plate 91 is shown.
One has a convex shape 912b on the side of the light exit surface 917. The convex shape 912b has an arbitrary size and shape (polygonal cone, cone, elliptical sphere, sphere, etc.), and converts a light beam reaching the convex shape 912b into a light beam having a large elevation angle with respect to the plane of the light guide plate 911. It has been found that good characteristics are exhibited by forming a substantially conical surface having a vertex angle of 120 degrees or less. The density and size of the convex shape 912b are the same as in the case of the concave shape described above.

Also in this embodiment, it is observed that the above-mentioned bright spots are uniformly distributed in the plane of the light guide plate 911, and that there is no linear strong bright line which impairs the visibility of the display which is the above-mentioned problem. Was done. Furthermore, it was confirmed that uniform visibility was obtained regardless of the observation position. And it was recognized that the illumination efficiency was further improved as compared with the first embodiment, as in the second embodiment.

An electronic device having a liquid crystal display device having the above-described front light in a display section is more compared with an electronic device having a liquid crystal display device using a conventional transflective reflector.
In the daytime, a bright display was obtained, and at night, the power required for illumination was small, and an electronic device having uniform and bright display illumination without generation of a specific bright line was realized. Further, brighter illumination than that of Example 1 was obtained. (Example 4) In FIG. 6, a light diffusing member layer 1012c is provided on the light exit surface 1017 side of the light guide plate 1011. The light diffusing member layer 1012c has an arbitrary size and shape, and the light flux reaching the light diffusing member layer 1012c is transmitted through the light guide plate 101.
It has a function of converting into a light beam having a large elevation angle with respect to one plane. That is, the light diffusing member layer 1012c has a light diffusing function toward the light exit surface 1013 and a light blocking effect toward the opposite light exit surface 1017. A light-shielding layer may be further provided to secure light-shielding properties. The density and size of the light diffusion member layer 1012c are the same as those in the case of the concave shape described above.
Also in the present embodiment, it was observed that the above-mentioned bright spots were uniformly distributed in the plane of the light guide plate 1011 and that there was no linear strong bright line which deteriorates the visibility of the display, which was the above-mentioned problem. Furthermore, it was confirmed that uniform visibility was obtained regardless of the observation position.

The same effect as in the previous embodiment was also confirmed in the electronic apparatus using the front light shown in this embodiment.

(Embodiment 5) In FIG. 7, a point-like light diffusing shape 1112x as described above is formed by a light guide plate 1117.
Above, an example is shown in which the light is distributed sparsely in the vicinity of the point light source 112 and densely as the distance from the point light source 112 increases. Although the light flux density in the light guide plate 1117 is high in the vicinity of the point light source 112, the light is diffused by the light diffusing shape 1112x,
Since the light flux density decreases as the distance from the point light source 112 increases, the light diffusion shapes 1112x are continuously arranged densely. This has enabled more uniform illumination.

Also in this embodiment, it is observed that the above-mentioned bright spots are uniformly distributed in the plane of the light guide plate 1117, and that there is no linear strong bright line which impairs the visibility of the display which is the above-mentioned problem. Was done. Furthermore, it was confirmed that uniform visibility was obtained regardless of the observation position.

The same effect was confirmed in the electronic device using the front light according to the present embodiment.

(Embodiment 6) Referring to FIG.
A transparent plate or a transparent sheet 128 is disposed on the side of the light emitting surface 1217 of 11. There is no close contact between the light guide plate 1211 and the transparent plate or the transparent sheet 128, and there is an air layer. If the surface of the light guide plate 1211 is slightly scratched, light rays guiding the inside are reflected there, and can be recognized from the surface as bright spots or bright lines. These are not only unsightly as illuminations arranged in front of the irradiation object, but also significantly lower visibility such as a decrease in contrast. Since the transparent plate or the transparent sheet 128 passes through the air layer with respect to the light guide plate 1211, the luminous flux from the light source 122 does not enter, and even if it is scratched, no bright spots or bright lines appear. In this case, since the relative area of the scratch is small, the influence on the visibility of the illuminated object 126 is extremely small. In order to use the light guide plate 1211 as front surface illumination, the presence of the transparent plate or the transparent sheet 128 is preferable. As the transparent plate or the transparent sheet 128, a transparent resin such as an acrylic resin, a polycarbonate resin, or an amorphous polyolefin resin, or an inorganic transparent material such as glass is used. In addition, if this transparent sheet 128 is used also as a transparent cover plate for protecting a liquid crystal display unit generally used for electronic devices such as a mobile phone device, a clock, a camera, and a data terminal device, the number of parts can be reduced. This is preferable because the reduction in reflection-type display performance due to surface reflection can be further reduced.

(Embodiment 7) FIG. 9 shows a liquid crystal display device 171 comprising a reflection type liquid crystal display and a front light disposed on the upper surface of the liquid crystal display according to any one of the first to sixth embodiments. It is a mobile phone device equipped with.

In a bright environment, the light source of the front light is turned off and the display is read by external light. In this case, as described above, a reflector having no transmittance and a high reflectance can be used instead of the conventional transflective reflector, so that a mobile phone device having a brighter liquid crystal display device can be realized. On the other hand, in a dark environment, the light source of the front light is turned on to enable display reading. In this case, as described above, the display surface can be illuminated with less power than in a conventional liquid crystal display device having a transflective plate, so that power consumption can be suppressed and battery life can be extended. Further, as described above, even when a point light source such as an LED and a miniature light bulb is used, uniform, bright, and easy-to-read nighttime illumination with no bright line can be realized.

(Embodiment 8) FIG. 10 shows a reflection type liquid crystal display and the above-described embodiment 1 arranged on the upper surface of the liquid crystal display.
6 is a timepiece equipped with a liquid crystal display device 181 including a front light shown in any one of (a) to (d).

In a bright environment, the light source of the front light is turned off and the display is read by external light. In this case, as described above, a reflective plate having no transmittance and a high reflectance can be used instead of the conventional transflective reflector, so that a timepiece having a brighter liquid crystal display device can be realized. On the other hand, in a dark environment, the light source of the front light is turned on to enable display reading. In this case, as described above, the display surface can be illuminated with less power than in a conventional liquid crystal display device having a transflective plate, so that power consumption can be suppressed and battery life can be extended. Further, as described above, LEDs,
Even when a point light source such as a miniature light bulb is used, uniform, bright and easy-to-read nighttime illumination without any bright line was realized.

(Embodiment 9) FIG. 11 shows a reflection type liquid crystal display and the above-described embodiment 1 arranged on the upper surface of the liquid crystal display.
6 is a data terminal device equipped with a liquid crystal display device 191 including a front light shown in any one of (a) to (d).

In a bright environment, the light source of the front light is turned off and the display is read by external light. In this case, as described above, instead of the conventional transflective reflector, a reflector having no transmittance and a high reflectance can be used, so that a data terminal device having a brighter liquid crystal display device can be realized. On the other hand, in a dark environment, the light source of the front light is turned on to enable display reading. In this case, as described above, the display surface can be illuminated with less power than in a conventional liquid crystal display device having a transflective plate, so that power consumption can be suppressed and battery life can be extended. Further, as described above, even when a point light source such as an LED and a miniature light bulb is used, uniform, bright, and easy-to-read nighttime illumination with no bright line can be realized.

(Embodiment 10) FIG. 12 shows a liquid crystal display device 201 comprising a reflection type liquid crystal display and a front light disposed on the upper surface of the liquid crystal display according to any one of the first to sixth embodiments. And 202 equipped with a camera.

In a bright environment, the light source of the front light is turned off and the display is read by external light. In this case, as described above, a reflector having no transmittance and a high reflectance can be used instead of the conventional transflective reflector, so that a camera having a brighter liquid crystal display device can be realized. On the other hand, in a dark environment, the light source of the front light is turned on to enable display reading. In this case, as described above, the display surface can be illuminated with less power than in a conventional liquid crystal display device having a transflective plate, so that power consumption can be suppressed and battery life can be extended. Furthermore, as described above, LE
D. Even when a point light source such as a miniature light bulb is used, a uniform, bright and easy-to-read nighttime illumination with no bright line can be realized.

[0053]

As described above, according to the present invention,
Electronic devices such as a mobile phone device, a clock, a data terminal device, and a camera having a liquid crystal display device having a uniform, bright or power-saving front light placed on the upper surface of a reflective liquid crystal display body in a display portion. realizable.

[Brief description of the drawings]

FIG. 1 is a sectional view and a perspective view showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram of one problem of a conventional technique.

FIG. 3 is a cross-sectional view of a conventional reflective liquid crystal display device.

FIG. 4 is a sectional view showing another embodiment of the present invention.

FIG. 5 is a sectional view showing another embodiment of the present invention.

FIG. 6 is a sectional view showing another embodiment of the present invention.

FIG. 7 is a plan view showing another embodiment of the present invention.

FIG. 8 is a sectional view showing another embodiment of the present invention.

FIG. 9 is a perspective view of a mobile phone according to the present invention.

FIG. 10 is a perspective view of a timepiece according to the present invention.

FIG. 11 is a perspective view of a data terminal device according to the present invention.

FIG. 12 is a perspective view of a camera according to the present invention.

FIG. 13 is a cross-sectional view of a conventional transflective liquid crystal display device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 光 light guide plate 2 ‥‥ point light source 6 ‥‥ irradiated object 10 突起 projection 812 a ａ concave 912 b 形状 convex 1012 c 凸 light diffusion member layer 1112 x ‥‥ light diffusion shape

Claims (15)

[Claims] 1. An electronic apparatus using a reflection type liquid crystal display device having a front light on an upper surface as at least an illuminating means as a display unit, wherein the front light has a plurality of point-like light diffusion shapes formed on a surface thereof. An electronic device comprising at least a light guide plate made of a transparent flat plate and a point light source arranged on an end face. 2. The electronic apparatus according to claim 1, wherein the light diffusion shapes are relatively sparsely distributed in the vicinity of the light source and continuously and densely distributed as the distance from the light source increases. 3. The electronic apparatus according to claim 1, wherein a columnar projection is provided as the light diffusing shape on a surface of the light guide plate facing the object to be illuminated. 4. The electronic apparatus according to claim 1, wherein a concave shape is provided as the light diffusion shape on a surface of the light guide plate that is different from a surface facing the object to be illuminated. 5. The electronic device according to claim 1, wherein a convex shape is provided as the light diffusing shape on a surface of the light guide plate different from a surface facing the object to be illuminated. 6. The electron according to claim 1, wherein a light diffusing member is provided as the light diffusing shape on a surface of the light guide plate which is different from a surface facing the object to be illuminated. machine. 7. The diameter or the maximum diameter of the light diffusion shape is 5.
The electronic device according to claim 1, wherein the electronic device has a thickness of not less than μm and not more than 300 μm. 8. The light diffusion shape has a diameter or a maximum diameter of 1
The electronic device according to claim 1, wherein the electronic device has a thickness of 0 μm or more and 100 μm or less. 9. A light emitting diode (L) as the point light source.
9. The electronic device according to claim 1, wherein the electronic device uses ED). 10. The electronic device according to claim 1, wherein a light bulb is used as the point light source. 11. The electronic apparatus according to claim 1, wherein a transparent plate or a transparent sheet is disposed on a surface of the light guide plate that is different from a surface facing the object to be illuminated. . 12. A portable telephone device, wherein the electronic device according to claim 1 is a portable telephone device. 13. A timepiece, wherein the electronic device according to claim 1 is a timepiece. 14. A camera, wherein the electronic device according to claim 1 is a camera. 15. A data terminal device, wherein the electronic device according to claim 1 is a data terminal device.