JP2002372711A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device wherein one backlight operates a plurality of liquid crystal display panels. SOLUTION: A light source 105 is disposed on the side of a light guide plate 106 and the two or more liquid crystal display panels 108 and 109 are provided on the different surfaces 110 and 111 of the light guide plate 106.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display having two or more liquid crystal display panels.
The present invention relates to a structure of a backlight used for these liquid crystal display panels.

[0002]

2. Description of the Related Art In a conventional liquid crystal display device, one liquid crystal display panel is provided with one backlight. FIG.
FIG. 1 is a side view showing an electronic apparatus including a conventional liquid crystal display device. In the figure, an electronic device 100 is a box-shaped housing 1.
01, two liquid crystal display devices 102 and 103 are provided. These liquid crystal display devices 102 and 103 emit light 10
Light sources 105 and 105 for projecting light sources 104 and 104, and a light source 10
5 and 105 include light guide plates 106 and 107 for guiding light 104 and 104 projected from the liquid crystal display panel, and liquid crystal display panels 108 and 109 for displaying characters, figures, and the like using the light guided by the light guide plates 106 and 107 as a backlight. It is configured.

[0003] The light sources 105, 105 are elongate cold-cathode tubes having a semi-cylindrical shape.
Diode (light emitting diode) may be used. The light sources 105, 105 are arranged along side surfaces of the light guide plates 106, 107 having a flat rectangular shape. The light guide plates 106 and 107 are formed of a transparent polycarbonate member. Bottom 1 of light guide plates 106 and 107
Lights 10 passing through the light guide plates 106 and 107 are provided at 10 and 110.
Grains (not shown) for diffusing the elements 04 and 104 are formed. Also, the back surfaces 111, 1 of the light guide plates 106, 107
11, the diffused light 104, 104
Reflectors 112, 112 are provided to prevent the light from passing through 6, 107 to escape to the outside. This reflection plate 112,
Reference numeral 112 denotes a sheet-like white background polyester film, and covers the entire back surfaces 111 and 111 of the light guide plates 106 and 107. The liquid crystal display panels 108 and 109 are installed on the front surfaces 113 and 113 sides of the light guide plates 106 and 107, and the reflection plates 112 and
It is located on the side opposite to 112. The display surfaces 114 and 115 of the liquid crystal display panels 108 and 109 are
Are located on the front face 116 and the rear face 117, respectively, and can be seen from the outside.

In this electronic device 100, a light source 10
Lights 104, 104 projected from 5, 105 enter light guide plates 106, 107 from their side surfaces. The entered light 104, 104 is guided and diffused in the light guide plates 106, 107 while being refracted between the upper surface 118 and the bottom surface 110 thereof. The diffusion of the light is promoted by the grain of the light guide plates 106 and 106. The light is reflected by the reflection plates 112 and 11.
2 and the back surface 11 of the light guide plates 106 and 106
Transmission to the 1,111 side is suppressed. The diffused light illuminates the liquid crystal display panels 108 and 109 and acts as a backlight thereof.

It should be noted that the liquid crystal display panel 1
As the electronic device 100 having 08 and 109, for example, a foldable mobile phone 100 capable of receiving an e-mail is known (see FIG. 12). Some of such mobile phones 100 include a main display panel 108, which is an original display screen, and a sub-display panel 109 for notifying reception of a mail (see FIGS. 12A and 12B). In the mobile phone 100, the main liquid crystal display panel 108 is closed in the folded state. Therefore, the sub liquid crystal display panel 109 is installed on the rear surface 117 side of the housing 101 so that the sub liquid crystal display panel 109 can be viewed from the outside even in the folded state. (See FIG. 10B).

[0006]

However, in the above-mentioned conventional liquid crystal display devices 102 and 103, light sources 105 and 105 are required according to the number of liquid crystal display panels 108 and 109, so that power consumption is inevitably large. There was a problem of becoming. In addition, since the liquid crystal display devices 102 and 103 also have a certain thickness, when the liquid crystal display panels 108 and 109 are arranged on the front and back of the electronic device 100, it is difficult to reduce the thickness. Was. Particularly in portable electronic devices, in recent years, there has been a strong demand for lighter and thinner devices, and in order to meet such needs, it is necessary to reduce power consumption, reduce the size of batteries, and reduce the thickness of display devices. However, according to the common technical knowledge of the related art, as described above, it is usual that one liquid crystal display panel 108 or 109 is provided with one backlight (other examples include, for example, a button of a mobile phone). An LED is provided for each button.) In general, a liquid crystal display device having a plurality of liquid crystal display panels has not been considered.

Accordingly, the present invention has been made in view of the above, and an object of the present invention is to provide a liquid crystal display device that can reduce the thickness and weight of an electronic device and has a plurality of liquid crystal display panels. I do.

[0008]

In order to achieve the above object, a liquid crystal display device according to the present invention comprises a light source, a light source, and a light guide for guiding light projected from the light source. A light plate, and two or more liquid crystal display panels installed on different surfaces of the light guide plate. In the present invention, light projected from a light source is guided by a light guide plate and illuminates a plurality of liquid crystal display panels installed on different surfaces of the light guide plate. This makes it possible to provide light to a plurality of liquid crystal display panels with a single backlight.

Further, the liquid crystal display device according to the present invention has a light source, a flat light guide plate for arranging the light source laterally and guiding light projected from the light source, and a light guide plate on the surface of the light guide plate. And a pair of liquid crystal display panels installed on the rear surface at positions that do not overlap in a plan view. In the present invention, light projected from a light source is guided by a light guide plate, and illuminates a liquid crystal display panel installed on both sides of the light guide plate. Thus, light can be provided to the liquid crystal display panels facing different directions with a single backlight.

Further, the liquid crystal display device according to the present invention has a light source, a flat light guide plate for arranging the light source laterally and guiding the light projected from the light source, and a light guide plate on the surface of the light guide plate. A pair of liquid crystal display panels installed on the back surface and at positions overlapping in a plane, and wherein the light guide plate is interposed in the middle of the pair of liquid crystal display panels and the liquid crystal display panel. It is characterized by having a reflective layer facing the reflective surface to the back of the panel. In the present invention, the reflection surface formed inside the light guide plate reflects light toward the liquid crystal display panel. Thereby, even when the liquid crystal display panel is installed at a position overlapping in a plane,
The brightness of the liquid crystal display panel can be increased.

Further, in the liquid crystal display device according to the present invention, the light source, the first light guide plate which guides the light projected from the light source while the light source is arranged laterally, and the first light guide plate are independent of the first light guide plate. A second light guide plate installed between the first light guide plate and the second light guide plate, and a light guide relay member for guiding and relaying light from the first light guide plate to the second light guide plate And a liquid crystal display panel provided on the first light guide plate and the second light guide plate. In the present invention, the light guide relay member relays light projected from the light source and passing through the first light guide plate to the second light guide plate. Thus, a single light source can supply backlights to a plurality of display panels.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. The present invention is not limited by the embodiment. The components of the embodiments described below include those that can be changed in design by those skilled in the art.

(Embodiment 1) FIG. 1 is a perspective view showing a liquid crystal display device according to Embodiment 1 of the present invention, and FIG. 2 is a side view of the liquid crystal display device shown in FIG. In the figure, the same components as those of the above-described conventional liquid crystal display device are denoted by the same reference numerals, and description thereof will be omitted. The liquid crystal display device 1 includes a single light source 105 and a single light guide plate 106.
, A reflector 112, and two liquid crystal display panels 108, 1
09 is configured. That is, the liquid crystal display device 1 supplies light to the two liquid crystal display panels 108 and 109 with one backlight. One of the liquid crystal display panels 108 is installed on the front surface 113 side of the light guide plate 106, and the other one 109 is installed on the back surface 111 side. As a result, the liquid crystal display devices 102 and 103
It has a pair of liquid crystal display panels 108 and 109 on the front and back. Here, the liquid crystal display panels 108 and 109 are installed at positions that do not overlap each other when the flat light guide plate 106 is viewed from one side in a plan view, that is, at positions that are different in plan view. In addition, portions on the front and back surfaces of the light guide plate 106 other than the portions where the liquid crystal display panels 108 and 109 are installed, in order to prevent light leakage from inside the light guide plate 106,
The reflecting plates 112, 112 are spread without gaps.
Each of the reflectors 112 has a rectangular shape.

In the first embodiment, the light source 105
Project the light 104 onto the light guide plate 106. The projected light 104 enters the side surface of the light guide plate 106 and
Enter into 06. The entered light is guided inside the light guide plate 106 while being refracted between the upper surface 118 and the bottom surface 110, and diffuses at a grain (not shown) provided on the bottom surface 110. At this time, the reflection plates 112, 112 totally reflect this light to suppress transmission from inside the light guide plate 106.
Thus, the light 104 is transmitted to the liquid crystal display panels 108 and 109.
Illuminates from the back side and acts as a backlight.

According to the first embodiment, the liquid crystal display device 1 supplies light to the two liquid crystal display panels 108 and 109 with one backlight, so that power consumption can be reduced. Further, in the liquid crystal display device 1, the number of backlights is half that of the conventional technology, so that the cost can be reduced. In particular, when an expensive cold cathode tube is used as the light source 105, the effect is large.

In the first embodiment, the light source 1
05 is one, but a plurality of light sources may be used in a backlight using a plurality of light sources for a single light guide plate (see FIG. 3). This liquid crystal display device 1 allows a single backlight to be effectively used for a plurality of liquid crystal display panels 108 and 109, as compared with a conventional technique in which a plurality of backlights are used for a plurality of liquid crystal display panels 108 and 109. This is because there is a feature in that the labor is saved.

In the first embodiment, the light source 1
Reference numeral 05 denotes a cold cathode tube, but may be an LED, a hot cathode tube, or another light emitting element. In the first embodiment, the number of the liquid crystal display panels 108 and 109 is two.
As long as it can be arranged on the light guide plate 106, the number may be more (see FIG. 4). Further, in the first embodiment, the light guide plate 106 includes the reflection plate 112 for suppressing a loss due to transmission of light.
It is not limited to a plate-like member or a sheet-like member, and may be a reflection film formed on the surfaces 111 and 118 of the light guide plate 106 by vapor deposition.

In the first embodiment, the light guide plate 106 has a flat rectangular shape. However, if the liquid crystal display panels 108 and 109 can be installed, the light guide plate 106 may have a flat polygonal shape or a circular shape. It may be shaped. further,
The shape of the light guide plate 106 may not be a uniform flat type as long as light can be guided. For example, when the shape of the electronic device 1 is irregular, the shape of the light guide plate 106 may be partially changed to adjust the position of the liquid crystal display panel 109 in accordance with the shape of the housing 101 so that the thickness of the light guide plate 106 is partially changed for the purpose of spacer. 2 may be provided (see FIG. 5). Light guide plate 1
The shape 02 may be a curved shape according to design requirements (see FIG. 6).

(Embodiment 2) FIG. 7 is a perspective view showing a liquid crystal display device according to Embodiment 2 of the present invention. In the figure, the same components as those of the above-described conventional liquid crystal display device are denoted by the same reference numerals, and description thereof will be omitted. The liquid crystal display device 3 includes a light source 105, a light guide plate 4, liquid crystal display panels 108 and 109, and reflection plates 112 and 112. The light guide plate 4 has a flat rectangular shape as a single form. The light guide plate 4 has an intermediate reflection layer 6 made of a reflection member uniformly formed on the plane of the light guide plate 4 between light guide layers 5 and 4 made of a transparent polycarbonate member. The light guide layers 5 and 4 have a grain (not shown) for diffusing light on the surface on the intermediate reflection layer 6 side. In addition, the liquid crystal display panels 108 and 109 include the light guide plate 4.
It is installed on the front and back. These liquid crystal display panels 108,
Reference numerals 109 are arranged at positions overlapping each other in a plane, and are installed at positions overlapping each other when the light guide plate 4 is viewed two-dimensionally from one side.

In the second embodiment, the light source 105
Project light from the side of the light guide plate 4. The projected light 104 enters the light guide plate 4 when entering the intermediate reflection layer 6.
Thereby, it is separated into the front surface 113 side and the back surface 111 side. Then, the light 104 is guided while refracting the light guide layer 5 in the light guide plate 4, and diffuses on a grain (not shown) provided on the intermediate reflection layer 6 side of the light guide plate 4. At this time, the intermediate reflection layer 6 of the light guide plate 4 has a role of reflecting light toward the liquid crystal display panels 108 and 109 and increasing the brightness of the liquid crystal display panels 108 and 109 together with the grain. As a result, the light 104 illuminates the liquid crystal display panels 108 and 109 from behind, and acts as a backlight.

According to the second embodiment, the intermediate reflection layer 6 of the light guide plate 4 is provided with the liquid crystal display panel 10 together with the grain.
It acts to increase the luminance of 8,109. Therefore, as described above, the liquid crystal display panels 108 and 109 are provided so as to overlap in a plane, and
When the reflectors 112, 112 cannot be provided over the entire back surface of the light receiving portions 8, 109, this has a useful effect, particularly in that the luminance of the overlapping portion can be increased.
In the second embodiment, the intermediate reflection layer 6 is formed over the entire surface of the light guide plate 4.
When the numbers 02 and 103 partially overlap, they may be partially formed only between the display panels 102 and 103 installed at the positions where the numbers 02 and 103 overlap (see FIG. 8).

(Embodiment 3) FIG. 9 is a perspective view of an electronic apparatus including a liquid crystal display device according to Embodiment 3 of the present invention. FIG. 10 is a perspective view of a liquid crystal included in the electronic apparatus shown in FIG. FIG. 2 is a side sectional view illustrating a configuration of a display device. In the figure, the same components as those of the above-described conventional liquid crystal display device are denoted by the same reference numerals, and description thereof will be omitted. In the third embodiment, the electronic device 7 is a wristwatch 7. The wristwatch 7 has a main body 9 having a main display section 108, an auxiliary section 12 having a sub display section 109 and connected to the main body 9 by a connection section 11, and fixed to the main body 9 and the auxiliary section 12 by pins 13 and 11. And the band portions 14 and 12 formed. Here, the display sections 108 and 109 of the main body 9 and the attachment section 12 are the liquid crystal display panels 108 and 109 of the liquid crystal display device 15.

The liquid crystal display device 15 includes the liquid crystal display panels 108 and 109, the light guide plates 106 and 107, and the reflection plate 1.
And a liquid crystal display panel, a light guide plate, and a reflection plate.
7 are formed. The liquid crystal display device 15 has two sets of the units 16 and 17. These units 16,
Numerals 17 are connected to each other by connecting portions 11 at the ends of the light guide plates 106 and 107. This connection part 11
The light guide relay member 18 for guiding and relaying light such as glass fiber is covered with a reflective layer 19 for reflecting light. The light source 1 that projects light onto the light guide plate 106 of the liquid crystal display panel 108 that is the main display unit 8 is provided inside the main body 9.
05 is installed. The light source 105 is arranged along the side surface of the light guide plate 106.

In the third embodiment, light 104 projected from light source 105 enters light guide plate 4 of main body 9 and is reflected by reflector 112 to illuminate liquid crystal display panel 108 as main display unit 8. . The light that has passed through the light guide plate 106 of the main body 9 enters the connection portion 11,
The light guide plate 10 of the attachment portion 12 guided by the connection portion 11
Enter into 7. This light is reflected by the reflection plate 112 and illuminates the liquid crystal display panel 109 as the sub display unit 10. Thereby, the different liquid crystal display panels 108 and 109 independent of each other can be illuminated by one light source 105. According to this configuration, light can be relayed between the different light guide plates 106 and 107 by the light guide relay member 18, so that one light source can be applied to the separate liquid crystal display panels 106 and 107.
Light can be supplied by one backlight. Further, according to this configuration, the light that has passed through the first light guide plate 106 can be guided to the next light guide plate 107 and used as a backlight, so that the light 104 from the light source 105 can be effectively used. it can.

[0025]

As described above, according to the liquid crystal display device of the present invention, the light projected from the light source is guided by the light guide plate, and the plurality of liquid crystals provided on different surfaces of the light guide plate. Since the display panel is illuminated, a single backlight can provide light to a plurality of liquid crystal display panels. Further, when the liquid crystal display panel is installed at the same position on the plane, the backlight is constituted by a single light guide plate, so that the liquid crystal display device can be made thinner. Further, according to the liquid crystal display device of the present invention, the light projected from the light source is guided by the light guide plate and illuminates the liquid crystal display panels provided on both sides of the light guide plate. Light can be provided to the liquid crystal display panels facing different directions.

Further, according to the liquid crystal display device of the present invention, the reflection surface formed inside the light guide plate reflects light toward the liquid crystal display panel. The brightness of the liquid crystal display panel can be increased even when the liquid crystal display panel is installed. Further, according to the liquid crystal display device of the present invention, the light guide relay member relays the light projected from the light source and passing through the first light guide plate to the second light guide plate. A backlight can be supplied to the panel.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a modification of the liquid crystal display device shown in FIG.

FIG. 3 is a sectional view showing a modification of the liquid crystal display device according to the first embodiment of the present invention;

FIG. 4 is a sectional view showing a modification of the liquid crystal display device according to the first embodiment of the present invention;

FIG. 5 is a sectional view showing a modification of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 6 is a sectional view showing a modification of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 7 is a perspective view showing a liquid crystal display device according to a second embodiment of the present invention.

FIG. 8 is a perspective view showing a modification of the liquid crystal display device according to the second embodiment of the present invention.

FIG. 9 is a perspective view of an electronic apparatus including the liquid crystal display device according to the third embodiment of the present invention.

FIG. 10 is a side sectional view showing a configuration of a liquid crystal display device included in the electronic apparatus shown in FIG.

FIG. 11 is an overall configuration diagram showing a conventional liquid crystal display device.

FIG. 12 is a side sectional view showing a main part of the liquid crystal display device shown in FIG. 3;

[Explanation of symbols]

 Reference Signs List 1 liquid crystal display device 105 light source 106 light guide plate 112 reflector 108, 109 liquid crystal display panel 112 reflector

Claims (4)

[Claims] A light source, a light guide plate for arranging the light source laterally and guiding light projected from the light source; and two or more liquid crystal display panels installed on different surfaces of the light guide plate; A liquid crystal display device comprising: 2. A light source; a flat light guide plate for arranging the light source laterally and guiding light projected from the light source; and a planar overlap on a front surface and a back surface of the light guide plate. A pair of liquid crystal display panels installed at positions not to be aligned. 3. A light source; a flat light guide plate for arranging the light source laterally and guiding light projected from the light source; and a planar overlap on a front surface and a back surface of the light guide plate. And a pair of liquid crystal display panels installed at the positions defined above, and the light guide plate is interposed inside the pair of liquid crystal display panels and has a reflective surface facing the back surface of the liquid crystal display panel. A liquid crystal display device having a reflective layer. 4. A light source, a first light guide plate for arranging the light source laterally and guiding light projected from the light source, and a second light guide plate installed independently of the first light guide plate A light guide relay member interposed between the first light guide plate and the second light guide plate, and guiding and relaying light from the first light guide plate to the second light guide plate; A liquid crystal display panel provided on the second light guide plate.