JPH1114986A - Illumination device, liquid crystal display device and electronic instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device low in power consumption and high in contrast by arranging light shielding parts on a first surface and a second surface on the opposite side to the first surface on the body side to be illuminated of a light transmission plate. SOLUTION: A light transmission plate 1, a point light source 2 of two LEDs(light emitting diodes) on the end face of the light transmission plate 1, a reflection member on the end face opposite to the point light source 2 and a light shielding member on the lower surface of the light transmission plate 1 are formed and a light shielding member 8 is formed on the upper surface of the light transmission plate 1 so as to be on the inner side than the forming position of the former light shielding member. A light absorbing member is used for the light shielding member 8 as a light shielding part but any material can be used, if the material makes light not transmit through the upper surface of the light transmission plate 1. By arranging such an illuminating device in front of a body 3 to be illuminated, the body 3 to be illuminated is observed by turning off the illumination at the time when the external light is brought enough and the body 3 to be illuminated is illuminated by turning on the illumination at the dark time when the external light is not bright enough.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device, a liquid crystal display device having a lighting function, and an electronic apparatus equipped with the liquid crystal display device having a lighting function.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal display device used for illumination with external light has a reflection function, and a reflection plate 102 is arranged on the back surface of a liquid crystal display panel 101 as shown in FIG. In addition, as shown in FIG. 17, the liquid crystal display device using the lighting device has the surface lighting device 103 disposed as a backlight on the back surface of the liquid crystal display panel 101, which is the object to be illuminated, and the lighting is always turned on from the back surface. . Further, a liquid crystal display device that uses external light when the outside is bright and turns on the backlight when the outside is dark, as shown in FIG. The lighting device 103 was arranged. (For example, see JP-A-57-
049271, JP-A-57-054926 and JP-A-58-58
-095780).

[0003]

However, the conventional liquid crystal display device having only an illumination function has a problem that it consumes a large amount of power because the light source is always turned on, and cannot be used for a long time when it is mounted on a cellular phone, for example. Had. In addition, a conventional liquid crystal display device having only a reflection function is:
Since there is no need to turn on the light source, there is a problem in that it can be used for a long time when mounted on a mobile phone, but cannot be used in a dark place outside. Furthermore, a conventional liquid crystal display device that can be used in both bright and dark environments by using a back-side illumination device and a semi-transmissive reflection plate has a problem that the display when using external light is dark. Was.

Therefore, the present invention solves the above-mentioned conventional problems, and provides an illuminating device which does not reduce the reflection function of the liquid crystal display device, a liquid crystal display device having an illuminating function, and a liquid crystal display device having an illuminating function. The present invention relates to an electronic device equipped with.

[0005]

According to a first aspect of the present invention, there is provided a lighting device comprising: a light guide plate disposed on a front surface of an object to be illuminated; and at least one light source disposed on an end face of the light guide plate. And a first light guide plate on the side of the illuminated body.
And a second surface opposite to the first surface is provided with a light shielding portion.

With this configuration, the light emitted from the light guide plate does not exit to the surface opposite to the illuminated body. When the light-shielding portion is formed by a light-shielding member, the light-absorbing member absorbs light, and when the light-shielding portion is formed by a reflection member, it can reflect light transmitted through the light guide plate,
It is possible to increase the efficiency of light applied to the object to be illuminated.

The light-shielding portion is formed around the first surface and the second surface of the light guide plate, and furthermore, the light-shielding portion of the light-shielding portion is formed on the first surface. The width from the end of the light plate is narrower than the width of the light-shielding portion formed on the second surface from the end of the light guide plate, so that light can be efficiently emitted to the illuminated body side. it can.

[0008] An air layer may be arranged between the light guide plate and the light shielding portion formed on the light guide plate.

The light source is a point light source or a bar light source, and a light source such as an LED has low power consumption.
It is effective when used for a portable electronic device.

[0010] In order to control the light emission, the first surface of the light guide plate is formed with a convex portion or a concave portion for emitting light from the light source, or the second surface of the light guide plate is formed. The surface may be provided with a convex or concave shape as the light diffusion shape.

A liquid crystal display device according to a twelfth aspect of the present invention is a liquid crystal display device having a lighting device having a light source and a light guide plate, and a liquid crystal panel, wherein the lighting device is disposed on the liquid crystal panel. A light-shielding portion is formed on a first surface of the light guide plate on the side where the liquid crystal panel is arranged, and a second surface opposite to the first surface; The lighting device and the liquid crystal panel are arranged so that a display area does not overlap.

With this configuration, the liquid crystal panel can be efficiently irradiated with light, and a bright display can be obtained when the light source is turned on.

Further, the light-shielding portion is provided on the first light guide plate.
And the liquid crystal panel is arranged on the basis of the position of the light-shielding portion, thereby facilitating alignment. Further, the width of the light shielding portion formed on the first surface from the end of the light guide plate is larger than the width of the light shielding portion formed on the second surface from the end of the light guide plate. And narrow configuration. Similarly, when the light-shielding portion formed on the second surface of the light guide plate is formed outside the display area of the liquid crystal panel, it becomes a display parting area, and the display of the liquid crystal panel is clearly seen. be able to.

Further, by mounting such a liquid crystal display device on an electronic device, an electronic device having excellent display quality can be obtained.

[0015]

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

(Embodiment 1) FIGS. 1 and 2 are views showing the configuration of a first embodiment of a lighting apparatus according to the present invention. The lighting device of FIG. 1 includes a light guide plate 1, a point light source 2 of two LEDs (light emitting diodes) on an end face of the light guide plate 1, a reflecting member 4 on an end face opposite to the point light source 2, and a light guide plate 1. The light shielding member 9 was formed on the lower surface, and the light shielding member 8 was formed on the upper surface of the light guide plate 1 so as to be inside the position where the light shielding member 9 was formed. Then, such a lighting device is arranged on the front surface of the illuminated body 3.

Although two LEDs are used as the light source here, one light source may be used or a fluorescent tube may be used.
Further, although the light absorbing members are used as the light shielding members 8 and 9 as the light shielding portions, any material can be used as long as it does not allow light to escape to the upper surface of the light guide plate. further,
It is also possible to use a light reflecting member such as aluminum instead of the light shielding member. For example, it is possible to form a light reflecting member on the upper and lower surfaces of the light guide plate using the same material as the reflecting member 4.

The light guide plate 1 was a transparent acrylic resin flat plate having a thickness of 1 mm and a refractive index of 1.49. On the surface opposite to the surface facing the illuminated body 3, a conical projection 5a having a bottom diameter of 50 μm, a height of 11.6 μm, and a vertex angle of about 130 degrees as shown in FIG. The projections 5 were formed as diffusion-shaped projections 5 and were arranged adjacent to each other at intervals of 150 μm as shown in FIG. At this time, the ratio of the area of the convex protrusion to the area of the illumination part of the light guide plate was about 10%. Since the refractive index of the light guide plate 1 is 1.49, the critical angle inside the light guide plate is about 42 degrees.

The light beam incident on the light guide plate 1 from the end face 7 of the light guide plate 1 is, as shown by light rays 6a and 6b, when the incident angle with respect to the surface of the light guide plate 1 is approximately 42 degrees or more. Repeat total reflection in Thereafter, when the light reflected on each surface of the convex protrusion 5 has an incident angle of approximately 42 degrees or less with respect to the surface of the light guide plate 1 on the side of the illuminated body 3, the light is emitted from the light guide plate 1 and the illuminated body 3 Can be illuminated.

The reflecting member 4 was adhered to the end surface of the light guide plate 1 through an adhesive material using a film on which aluminum was deposited. Since the reflection member 4 returns the light beam guided to the inside of the light guide plate 1 and reaching the end face to the inside of the light guide plate 1 again, the illumination efficiency can be improved. At this time, the scattered light leaking from the end surface portion of the light guide plate 1 and the reflection member 4 is blocked by the light shielding members 8 and 9 arranged on the upper and lower sides of the light guide plate 1, so that the illumination light becomes uneven and the observer side. No unnecessary light leakage occurs. Further, when viewed from the observer side, the lower light shielding member 9 is hidden by the upper light shielding member 8, so that the scattered light on the surface of the light shielding member 9 was not seen, and the appearance was improved.

As the reflection member, a film on which a material other than aluminum is deposited, a thin plate of aluminum or the like may be adhered via a double-sided tape or an adhesive, or a material on which a thin film of aluminum or the like is deposited may be used.

As the transparent material forming the light guide plate 1, other than acrylic resin, a transparent resin such as polycarbonate resin and amorphous polyolefin resin, an inorganic transparent material such as glass, or a composite thereof may be used. Examples of the method of forming the convex protrusions 5 include injection molding, thermosetting resin, photocurable resin, etching, and joining a film or resin layer on a transparent resin or a glass flat plate.

With the above arrangement, the present illuminating device is arranged in front of the illuminated body 3 so that when the external light is sufficiently bright, the illumination is turned off and the illuminated body 3 is observed. It is possible to realize a favorable lighting device that can turn on the lighting and illuminate the illuminated body.

However, as shown in FIG. 3, since the intersection line between the surface of the light guide plate 1 and the convex protrusion 5a and the vertex of the cone have a minute curved surface, some reflected light leaks to the observer side, and Is observed as a bright spot for the person. Therefore, the size of the projection 5 having a convex shape is not more than a size that is not bothersome to the naked eye, and is preferably 300 μm or less. Further, the thickness is required to be 5 μm or more so that the influence of diffraction of visible light does not occur. Furthermore, the size is about 10 for convenience in manufacturing.
It is desirable that the thickness be in the range of μm to 100 μm.

The efficiency of illumination increases with an increase in the area ratio of the protruding projections to the area of the illuminating portion of the light guide plate. However, the parallel light transmittance in the direction perpendicular to the light guide plate decreases, so that the visibility increases. Becomes worse and is not practical at 50% or more. Further, if it is too small, the lighting efficiency is reduced, so that 5% or more is necessary. Therefore, it is desirable that the area ratio of the convex protrusion to the area of the illumination part of the light guide plate is 5% to 50%.

Further, in addition to the conical shape shown in FIG. 3, the protrusion may have a hemispherical convex shape as shown in FIG. FIG.
And a hemispherical concave shape as shown in FIG. Further, the light guide plate may have a cylindrical convex shape as shown in FIG. 7 or a cylindrical concave shape as shown in FIG.

(Embodiment 2) In the lighting device of Embodiment 1, the light-shielding portion is formed by a light-shielding member. In this embodiment, the light-shielding portions 8 and 9 are not light-absorbing members but reflection members, and aluminum thin films are used. . An air layer is provided between the light guide plate 1 and the light guide plate 1 so that the air layer does not adhere to the air layer. Then, the scattered light leaking from the end face portion of the light guide plate 1 and the reflection member 4 is reflected by the light shielding members 8 and 9 and returned to the inside of the light guide plate 1 again, so that the illumination efficiency is improved as compared with the first embodiment. Further, when viewed from the observer side, the lower light shielding member 9 is hidden by the upper light shielding member 8, so that the appearance of the light reflected by the lower light shielding member 9 due to the direct view of the observer is not reduced.

Further, as shown in FIG. 9, the reflecting member on the end face of the light guide plate 1 and the upper and lower light shielding members are integrated into a reflecting member 10. By integrating the reflecting members, it was possible to eliminate light leakage from between the reflecting members. Further, the reflection member 1
Lighting efficiency can be further improved by reducing the area that is in close contact between the light guide plate 1 and the light guide plate 1 and increasing the area where the air layer exists.

(Embodiment 3) FIGS. 10 and 11 are views showing the configuration of a third embodiment of the lighting apparatus according to the present invention. The lighting device shown in the figure is an application of the lighting device used in the first embodiment, in which light-shielding portions are provided also on the upper and lower surfaces of the light source. As shown in FIG. 10, the light shielding member 11 is arranged on the light source, and is arranged so as to overlap with the light guide plate. Further, a light blocking member 12 is formed below the light source. Similarly, a light blocking member is formed so as to overlap the light guide plate. The formed position is formed so that the light shielding member 11 covers the light shielding member 12 in the same manner as the light shielding members 8 and 9. That is, the light-shielding member 11 is disposed so as to be inside the light-shielding member 12. At this time, light absorbing members were used for the light shielding members 11 and 12.

By adopting such a configuration, when the illuminated object illuminated by the illuminating device is viewed from the front, the light source is not directly seen and the scattered light from the lower light shielding member 12 is not directly seen. Become. In addition, since the light emitted from the point light source 2 to the lower side is blocked by the lower light-blocking member 12, uneven brightness of the illumination does not occur on the illuminated body.

When one or both of the upper light-shielding member 11 and the lower light-shielding member 12 are made to be reflection members, light that has not been incident on the light guide plate 1 can be made to be incident on the light guide plate 1 so that illumination is performed. Efficiency improved. Further, when light reflecting members are disposed as light shielding portions on the upper surface and the lower surface of the light guide plate, they can be formed integrally with the reflecting member 4.

Further, at least one LED is arranged.
When a cold-cathode tube was disposed as a bar-shaped light source instead of the point light source described above, unevenness of illumination brightness near the light source, which occurred in the case of an LED, was eliminated.

(Embodiment 4) FIGS. 12 and 13 are views showing the configuration of a fourth embodiment of the lighting apparatus according to the present invention. FIG. 12 is a sectional view taken along line AA ′ of FIG. In the lighting device according to the third embodiment, the reflecting members 4 are arranged on the end surfaces of the light guide plate 1 excluding the surface on which the light source is arranged, and the reflecting members are arranged above and below all the end surfaces of the light guide plate 1. It was arranged as a light shielding member, and the upper reflecting member 13 was arranged inside the lower reflecting member 14.

At this time, when the illuminated object illuminated by the illuminating device is viewed from the front, the light source is not directly visible, and the light reflected or scattered by the lower reflecting member 12 is not directly visible.
In addition, since the light emitted from the light source to the lower side is blocked by the lower reflecting member 12, unevenness in brightness does not occur in the illuminated body. Further, the scattered light leaking from the end face portion of the light guide plate 1 is incident on the light guide plate 1 by the upper and lower reflection members, so that the illumination efficiency is improved.

(Embodiment 5) FIG. 14 shows a configuration of a liquid crystal display device in which an object to be illuminated is a liquid crystal panel, and the lighting device used in the above-described embodiment is arranged on the front surface of the liquid crystal panel.
Here, a configuration like the third embodiment shown as one embodiment will be described as an example.

The liquid crystal panel is composed of upper and lower substrates 2 sandwiching a liquid crystal layer 21.
2, 23. Then, a polarizing plate is arranged outside thereof. The configuration of the liquid crystal panel is a simple matrix type liquid crystal panel, a liquid crystal panel using active elements such as TFTs and MIMs, a liquid crystal panel using a polymer liquid crystal material in which a polymer is dispersed in liquid crystal, Can be used. In the case of a polymer dispersion type liquid crystal panel, it is not necessary to use a polarizing plate. In the case of a simple matrix type liquid crystal panel,
In particular, when using an STN type liquid crystal, at least one retardation plate is provided as necessary. Since the liquid crystal panel is a reflective liquid crystal panel, a brighter display can be obtained by using a liquid crystal panel using only one polarizing plate.

In such a liquid crystal panel, the region 30
Indicates a display area. The display area refers to an area represented as a lit pixel by an electrode formed on a liquid crystal panel.

At this time, the light guide plate and the liquid crystal panel are arranged so that the position of the end face of the light shielding portion formed on the upper surface of the light guide plate 1 and the display area substantially overlap. Therefore, the angle θ is approximately 90 degrees.

However, in order to prevent the display of the liquid crystal panel and the light-shielding portion from overlapping with each other, the end of the light-shielding portion and the display area are shifted by at least one dot (one pixel of the display pixel). Furthermore, considering the case where the liquid crystal panel is viewed at an angle, the angle of θ (that is, the elevation angle)
Is desirably set to approximately 60 degrees or less.

Most of the angle of inclination when tilted is within 30 degrees from the front.
It is necessary that 11 does not cover the display area 30 of the liquid crystal display device. Therefore, it is desirable to arrange the light shielding members 8 and 11 so that the elevation angle θ with respect to the display area 30 is 60 degrees or less.

With such a configuration, since the light guide plate is a transparent plate, when there is sufficient external light, the external light can be used as in the related art even if the light source 2 is turned off, and this has almost no effect on display quality. Do not give. When there is not enough external light, the light source 2 is turned on to use the illumination light from the light guide plate. At this time, the brightness of the display of the liquid crystal display device depends on the brightness of the light source, but the same contrast as when external light is used can be obtained. Moreover, despite the illumination from the front of the liquid crystal display device, an extremely good display was obtained in which the display quality did not deteriorate due to the reflected light on the surface of the liquid crystal display device when viewed from the front.

As described above, by using the illuminating device of the present invention for a liquid crystal panel, the display is dark and the visibility is poor even when there is sufficient external light, and when the backlight is turned on when there is not enough external light, it becomes a transmissive type. Therefore, the disadvantage of a conventional liquid crystal display device using a transflective reflector and a backlight, such as a decrease in contrast, can be solved, and a liquid crystal display device with excellent display quality can be obtained.

In this embodiment, the illumination device has been described using the above-described embodiment. However, the present invention is not limited to this, and the configuration of the illumination device as in the above-described embodiment is used. be able to.

When a light reflecting member is used as the light shielding portion, the light shielding member may be formed of the same material and the same structure as the reflecting member 4.

When a light-absorbing material is used as the light-shielding portion, the outer frame of the liquid crystal panel can be provided as it is. Therefore, when the liquid crystal display device according to the present embodiment is arranged in an electronic device described later, the outer frame (that is, the housing) of the electronic device is used as a light shielding unit. Since the outer frame of the electronic device is arranged in the shape of the light-shielding portion 8 or 11, no extra light is emitted to the observer, and an electronic device with excellent display quality can be obtained. .

Embodiment 6 FIG. 15 shows an example in which the liquid crystal display device of the present invention is used in a mobile phone. The liquid crystal display device used in Example 5 was used as the display unit 50 of the mobile phone 40. When external light was used, a brighter display was obtained than with a display unit using a conventional liquid crystal display device using a transflective reflector.

Further, even when the lighting device is turned on, the same contrast as when using the external light can be obtained, so that the mobile phone can be used without trouble even in a dark environment where there is not enough external light. Even when the liquid crystal display device of the present invention is used not only for a mobile phone but also for an electronic device such as a portable electronic device such as an electronic organizer or a measuring device, a bright display is obtained when external light is used, and the lighting device is turned on. In this case, the electronic device can obtain the same contrast as when using external light.

[0048]

According to the present invention, as described above,
It is possible to provide a thin surface illumination suitable for a notice board, a display body, and the like using external light. Further, it is possible to provide a low-power-consumption and high-contrast liquid crystal display device in which the same contrast as when external light is used can be obtained even when the lighting device is turned on. Furthermore, in applications that require power saving, such as portable electronic devices, the display can be used with the lighting turned off in bright places, and can be used in dark environments without reducing the contrast even when the lighting is on, with low power consumption and high contrast display. An electronic device having a unit can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view showing an embodiment of the present invention.

FIG. 3 is an explanatory view of a projection having a convex shape according to the embodiment of the present invention.

FIG. 4 is an explanatory view of a protrusion having a convex shape according to the embodiment of the present invention.

FIG. 5 is an explanatory view of a concave shape in the embodiment of the present invention.

FIG. 6 is an explanatory view of a concave shape in the embodiment of the present invention.

FIG. 7 is an explanatory diagram of a projection having a convex shape according to the embodiment of the present invention.

FIG. 8 is an explanatory view of a concave shape in the embodiment of the present invention.

FIG. 9 is a sectional view showing an embodiment of the present invention.

FIG. 10 is a sectional view showing an embodiment of the present invention.

FIG. 11 is a plan view showing an embodiment of the present invention.

FIG. 12 is a sectional view showing an embodiment of the present invention.

FIG. 13 is a plan view showing an embodiment of the present invention.

FIG. 14 is a sectional view showing an embodiment of the present invention.

FIG. 15 is a diagram showing an example of the present invention.

FIG. 16 is a sectional view showing a conventional technique.

FIG. 17 is a sectional view showing a conventional technique.

FIG. 18 is a sectional view showing a conventional technique.

[Explanation of symbols]

 1. Light guide plate 2. Point light source 3. Illuminated object 4. Reflective member 5. 8.1.13 Upper light-blocking member 9.12.14 Lower protrusion

Claims (12)

[Claims] An illumination device comprising: a light guide plate disposed on a front surface of an object to be illuminated; and at least one light source disposed on an end surface of the light guide plate. A lighting device comprising a first surface and a light-shielding portion disposed on a second surface opposite to the first surface. 2. The lighting device according to claim 1, wherein the light shielding portion is formed around the first surface and around the second surface of the light guide plate. 3. The width of the light-shielding portion formed on the first surface from the end of the light guide plate is different from the width of the light-shielding portion formed on the second surface from the end of the light guide plate. The lighting device according to claim 1, wherein the lighting device is narrow with respect to the width. 4. The lighting device according to claim 1, wherein an air layer is disposed between the light guide plate and the light blocking portion formed on the light guide plate. 5. The lighting device according to claim 1, wherein the light source is a point light source or a bar light source. 6. The lighting device according to claim 1, wherein a convex portion or a concave portion for emitting light from the light source is formed on the first surface of the light guide plate. 7. The lighting device according to claim 1, wherein a convex shape or a concave shape is provided as the light diffusion shape on the second surface of the light guide plate. 8. A liquid crystal display device comprising: an illuminating device having a light source and a light guide plate; and a liquid crystal panel, wherein the illuminating device is disposed on the liquid crystal panel. A light-shielding portion is formed on the first surface on the side on which the light-emitting device is arranged and on a second surface opposite to the first surface, and the light-shielding portion and the display area of the liquid crystal panel are not overlapped with each other. A liquid crystal display device comprising a lighting device and the liquid crystal panel. 9. The light-shielding portion is formed around the first surface and the second surface of the light guide plate, and the liquid crystal panel is arranged based on the position of the light-shielding portion. 9. The liquid crystal display device according to claim 8, wherein: 10. The width of the light shielding portion formed on the first surface from the end of the light guide plate is different from the width of the light shielding portion formed on the second surface from the end of the light guide plate. The liquid crystal display device according to claim 9, wherein the liquid crystal display device is narrow with respect to the width. 11. The liquid crystal display device according to claim 10, wherein the light shielding portion formed on the second surface of the light guide plate is formed outside a display area of the liquid crystal panel. 12. An electronic apparatus comprising the liquid crystal display device.