JP2003098545A - Double-sided display type liquid crystal display device and portable electronic device having the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a thin double-sided display type liquid crystal display device which can display easily in a bright place or a dark place with low power consumption and low power consumption. SOLUTION: The double-sided display type liquid crystal display device 1 of the present invention comprises:
The liquid crystal display panel 41 and the light guide plate 31 form a laminate, and display is performed on the front side and the back side of the laminate. The liquid crystal display panel 41 has a reflective display area 41a corresponding to the front side display and a transflective display area 41b corresponding to the back side display.
On the other hand, the light guide plate 31 has a region 31a having a front light function and a region 31b having a backlight function. The light guide plate 31 and the liquid crystal display panel are arranged such that the reflective display area 41a and the area 31a having the front light function overlap, and the reflective and transmissive display area 41b and the area 31b having the backlight function overlap. 41 are laminated.

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 device having a double-sided display function and a portable electronic device having the same.

[0002]

2. Description of the Related Art Conventionally, in a portable electronic device such as a mobile phone, a double-sided display type liquid crystal display device provided with a sidelight type illumination device as disclosed in, for example, Japanese Patent Laid-Open No. 2001-67049. Is proposed.

This double-sided display type liquid crystal display device 101, as shown in FIG. 24, has liquid crystal display panels 141a and 141b.
And a side light type illumination device 130 including a light source 132 and a light guide plate 131, and a liquid crystal display panel 141a,
141b and the light guide plate 131 form a laminated body, and display is performed on the front surface side and the rear surface side of this laminated body.

Here, the liquid crystal display panels 141a, 141
Both b are transmissive. Further, the sidelight type lighting device 130 has only a backlight function, and has a liquid crystal display panel 141a for front side display and a liquid crystal for backside display on both sides of a light guide plate 131 included in the lighting device 130. The display panel 141b is laminated. Therefore, the laminated body has a three-layer structure in which the light guide plate 131 is sandwiched between the two liquid crystal display panels 141a and 141b in the thickest region.

[0005]

However, the above-mentioned prior art has the following problems. First, the liquid crystal display panel 141a and the light guide plate 1 are formed in the thickest region of the laminated body.
31 has a three-layer structure in which the liquid crystal display panel 141b is laminated in this order, and thus there is a problem that the thickness of the entire double-sided display type liquid crystal display device 101 becomes large.

Secondly, both the liquid crystal display panel 141a compatible with the front side display and the liquid crystal display panel 141b compatible with the back side display are transmissive displays, and even when the ambient light is bright, sidelight type display is possible. Backlight illumination by the illumination device 130 is required, and there is a problem that power consumption is considerably large.

Therefore, in such a portable electronic device equipped with such a conventional double-sided display type liquid crystal display device 101, the thickness of the double-sided display type liquid crystal display device 101 inevitably increases the thickness of the display-related portion of the device. Will end up. Further, since a large amount of power is consumed for display, there is a problem that the battery life is shortened.

The present invention has been made in view of the above-mentioned problems of the prior art, and can be used in a bright place or a dark place.
Moreover, it is an object of the present invention to provide a thin double-sided display type liquid crystal display device. Another object of the present invention is to provide a thin portable electronic device having a long battery life while maintaining the visibility of double-sided display.

[0009]

In order to achieve the above object, a double-sided display type liquid crystal display device of the present invention comprises a liquid crystal display panel and a sidelight type illuminating device including a light source and a light guide plate. In the double-sided display type liquid crystal display device in which the panel and the light guide plate form a laminated body and display is performed on the front surface side and the back surface side of the laminated body, the laminated body includes the liquid crystal display panel and the light guide plate. Is one layer each.

The liquid crystal panel forming one layer is i)
It may be a single-panel type in which the front side display and the back side display are separately performed within the plane of one liquid crystal panel, or ii) a liquid crystal panel in which a plurality of liquid crystal panels are arranged in the plane May be a front surface side display, and the remaining liquid crystal panel may be a multi-panel type for back side surface display.

The light guide plate forming one layer is i) one light guide plate and has a surface-processed area having a front light function and a surface-processed area having a backlight function. The light guide plate may be a single type, or ii) the light guide plate in which a plurality of light guide plates are arranged in a plane is surface-treated to have a front light function, and the remaining light guide plates have a backlight function. It may be a multi-sheet type whose surface is processed.

With this configuration, the light guide plate has not only the backlight function but also the front light function, so that it is more effective than the conventional three-layer type double-sided display type liquid crystal display device equipped with the sidelight type illumination device. The number can be reduced, and the liquid crystal display device of double-sided display type can be thinned.

Further, the double-sided display type liquid crystal display device of the present invention comprises a liquid crystal display panel and a side light type lighting device including a light source and a light guide plate, and the liquid crystal display panel and the light guide plate are laminated bodies. None, in a double-sided display type liquid crystal display device that performs display on the front side and the back side of this laminate, the liquid crystal display panel has a reflective display area corresponding to the front side display and the back side display. And a reflective / transmissive display region corresponding to, the light guide plate has a region having a front light function and a region having a backlight function, and the reflective display region and a region having the front light function. Are overlapped with each other, and the reflective / transmissive display area and the area having the backlight function are overlapped with each other. The sidelight type illumination device is configured to turn off the illumination when the ambient light is bright or when the display is unnecessary.

With this structure, the light guide plate having one layer can be effectively utilized, and not only the bright reflection / transmission type display by the backlight illumination on the back side can be performed but also the front side illumination by the front side illumination. A reflective display can be realized.

Further, when the ambient light is bright, the illumination by the illuminating device is not necessary for the reflective display or the transflective display, so that the backlight illumination is always required. Then, the power consumption can be considerably reduced.

Further, the double-sided display type liquid crystal display device of the present invention comprises a liquid crystal display panel and a side light type lighting device including a light source and a light guide plate, and the liquid crystal display panel and the light guide plate are a laminated body. None, in a double-sided display type liquid crystal display device that performs display on the front side and the back side of this laminate, the liquid crystal display panel has a reflective display area corresponding to the front side display and the back side display. A transmissive display region corresponding to, the light guide plate has a region having the front light function and a region having a backlight function, the reflective display region and the region having the front light function. Are overlapped with each other, and the transmissive display area and the area having the backlight function are overlapped with each other.

With this structure, the light guide plate having one layer can be effectively used, and not only bright transmissive display can be performed by the backlight illumination on the back side but also bright reflection by the front light illumination on the front side. A type display can be realized.

Further, when the ambient light is bright, the illumination of the illuminating device is not necessary for the reflective display, so that the backlight consumption is always required, so that the consumption is lower than that of the conventional double-sided display type liquid crystal display device. Can be converted to electricity.

Further, in the double-sided display type liquid crystal display device of the present invention, the sidelight type illumination device has a light source separately for a region of the light guide plate having a frontlight function and a region having a backlight function. It is characterized by

With this structure, when the ambient light is dark and the front surface side display is used or the back surface side display is used, the illumination is provided in accordance with each of the displays, so that an unnecessary display surface can be displayed. Lighting can be turned off and power consumption can be reduced.

The light guide plate is characterized in that a reflection function layer is provided at a boundary between the region having the front light function and the region having the backlight function.

With this configuration, it is possible to prevent light leakage from the front light area side to the back light area side or from the back light area side to the front light area side, thereby improving the light use efficiency and reducing the light use efficiency. Power consumption can be reduced.

As a method of forming the reflection function layer, i) a transparent resin to be the front light area, a white resin, and a transparent resin to be the backlight area are integrally molded. As a result, a light guide plate is obtained in which a white resin serving as a reflection portion is formed at the boundary between both areas. Alternatively, ii) a reflection sheet is sandwiched between one side surface of the light guide plate of the front light area and one side surface of the light guide plate of the backlight area which are separately formed. Alternatively, iii) a slit is provided at the boundary between the front light region and the backlight region of one light guide plate, and the reflection sheet is inserted into the slit.

Further, the double-sided display type liquid crystal display device of the present invention comprises a reflection sheet which is bent into an L-shape by a folding screen corresponding to the thickness of the light guide plate, and has a region having a front light function of the light guide plate. A slit is provided at a boundary with a region having a backlight function, and the reflection sheet is attached to the back surface of the backlight region of the light guide plate by inserting the folding sheet of the reflection sheet into the slit. To do.

With this structure, the slits of the light guide plate can be formed by simple molding without performing complicated molding such as two-color molding, or the slits can be formed simultaneously with the surface processing of the light guide. You can Also, the reflecting sheet to be inserted can be used as a reflecting plate arranged on the back surface of the light guide plate in the backlight area by simply bending it into an L-shape and inserting the bent side into the slit. The reflective function layer at the boundary between the region having the backlight function and the region having the backlight function and the reflective layer on the back surface of the light guide plate in the region having the backlight function can be easily manufactured together at low cost.

By providing such a double-sided display type liquid crystal display device of the present invention in a portable electronic device, a double-sided display type liquid crystal display device which consumes less power and is thinner than conventional ones can be used. For portable electronic devices that were
The battery life can be made longer and thinner than before.

[0027]

1 is an exploded perspective view of a liquid crystal display device according to the present invention. The liquid crystal display device 1 includes a double-sided display type liquid crystal display panel 41 capable of displaying on the front surface side and the back surface side, a light source 32, and a sidelight type lighting device 30 having a light guide plate 31 made of polycarbonate or acrylic. , And a resin holder 20. The holder 20 has a U-shaped frame 21 selected to have a size larger than the outer shapes of the double-sided display type liquid crystal display panel 41 and the light guide plate 31.
By holding a laminated body of the double-sided display type liquid crystal display panel 41 and the light guide plate 31 in the frame 21, the laminated body is held and protected. On the open side of the U-shape of the frame 21, a driver 44 and a controller 4 for displaying are displayed.
A holding / protecting portion 22 that holds / protects the frame 5 is formed integrally with the frame 21.

The sidelight type lighting device 30 includes the light guide plate 3
1 and a light source 32. The light guide plate 31 has a front light area 31a for front side display and a back light area 31b for back side display. On the back surface of the backlight region 31b of the light guide plate 31, that is, the surface not facing the double-sided display type liquid crystal display panel 41, a PET reflection sheet 33 is overlaid in order to improve the surface brightness of the back side display. Further, in order to improve the display quality and brightness, a laminated body of a diffusion sheet and a lens sheet made of PET, a lens sheet, or a light control sheet such as a diffusion sheet is provided on the surface facing the double-sided display type liquid crystal display panel 41. Sheets 34 are overlaid. In addition, the light guide plate 31
A light source 32 is arranged on the side surface of the. The detailed arrangement will be described later.

The double-sided display type liquid crystal display panel 41 has a reflection type panel 41a for performing a front side display and a reflection / transmission type panel 41b for performing a back side display. The reflection type panel 41a is a conductive panel. Front light area 3 of light plate 31
1a and the reflective / transmissive panel 41b are stacked so as to overlap the backlight region 31b of the light guide plate 31.

The double-sided display type liquid crystal display panel 41 is also provided.
One side is a TCP (tape carrier) on which a driver 44 for displaying and a controller 45 are mounted.
Package) 42 is connected. Two folds 43a and 43b are provided facing each other between the driver 44 and the controller 45 on the TCP 42. On the other hand, the holding / protecting portion 22 of the holder 20 is provided with a rectangular opening portion 22a selected to have a size to fit the driver 44 and the controller 45.

Therefore, the TCP 42 is folded so that the holding / protecting portion 22 of the holder 20 is wound from the outside.
The liquid crystal display panel 41 can be attached to the holder 20 by bending the U-shaped portion 3 (43a, 43b) and fitting the driver 44 from below and the controller 45 into the opening 22a from above. As a result, the driver 44 is in the same layer as the liquid crystal display panel 41,
The controller 45 is held by the holder 20 in the same layer as the light guide plate 31.

The laminated body constructed as described above has a front casing 11 having a window frame 12 for displaying on the front side.
And a back housing 5 having a window frame 52 for displaying the back side
It is stored and held by being sandwiched by 1. As a result, the double-sided display type liquid crystal display device 1 is completed. In addition,
A transparent material is sandwiched between the window frame 12 of the front casing 11 and the window frame 52 of the rear casing 51 to protect the display surface and prevent foreign matter from entering.

2 to 8 are plan views showing the detailed arrangement of the light sources provided on the side surface of the light guide plate. FIG. 2 is a plan view showing the positional relationship between the light source and the light guide plate of the present embodiment. The light guide plate 31 is divided into a front light region 31a and a backlight region 31b, and has a rectangular shape in plan view. is doing. At least one LED as the light source 32 is arranged on each of the short sides of the light guide plate 31 on the front light region 31a side and the backlight region 31b side in plan view. When the front side display is performed, only the front light area 31a is turned on, and when the back side display is performed, only the backlight area 31b is turned on by the light source 32.

Alternatively, as shown in FIG. 3, one or more LEDs as the light source 32 are provided on the long side of the light guide plate 31 in a plan view and over both the front light area 31a and the back light area 31b. Will be placed. When the front side display is performed, only the front light area 31a is turned on, and when the back side display is performed, only the backlight area 31b is turned on by the light source 32.

Alternatively, as shown in FIG. 4, at least one LED as the light source 32 is arranged at each of the corners on the front light region 31a side and the backlight region 31b side of the light guide plate 31 in plan view. It In this case, 1
More than one light source 32 may be placed in one corner,
Further, they may be arranged at both two corners of each area. When the front side display is performed, only the front light area 31a is turned on by the light source 32, and when the back side display is performed, only the backlight area 31b is turned on by the light source 32.

Alternatively, as shown in FIG. 5, one or more LEDs as the light source 32 are arranged only on the short side of the light guide plate 31 on the backlight region 31b side in plan view, and when the LED is on, the front light region 31a. Alternatively, both areas of the backlight area 31b may be illuminated by the light source 32.

Alternatively, as shown in FIG. 6, one or more LEDs as the light source 32 are arranged only at the corners of the light guide plate 31 on the backlight region 31b side in plan view, and the front light region 31a is lit when the LED is turned on. Backlight area 31b
Both areas may be illuminated.

Alternatively, as shown in FIG. 7, a linear light source such as a stick light source for converting a cold cathode fluorescent lamp (CCFT), a hot cathode fluorescent lamp (HCFT), or a point light source (LED or the like) into a linear light source as the light source 32 is a flat surface. It may be arranged on the short side of the light guide plate 31 so as to illuminate both the front light region 31a and the backlight region 31b at the time of lighting.

Alternatively, as shown in FIG. 8, a linear light source such as a CCFT, an HCFT, or a stick light source that converts a point light source (such as an LED) into a linear light source as the light source 32 is viewed in plan and has a long side of the light guide plate 31. It is also possible to illuminate both the front light area 31a and the back light area 31b when lit.

9 to 14 are perspective views showing the shape of the light guide plate. As shown in FIG. 9, the light guide plate 31 is a rectangular parallelepiped when viewed three-dimensionally. The front light area 31a and the back light area 31b are made of the same transparent resin inside the light guide plate 31, and are distinguished by the surface processing and the laminated sheets. Detailed surface processing and sheets to be laminated will be described later.

Alternatively, as shown in FIG. 10, the light guide plate 31
Is the light source 32 as shown in FIG. 3 or FIG.
If it is placed on only one of the long sides of
It is preferable that the wedge shape is thinned away from the surface on which the light source 32 is located.

Alternatively, as shown in FIG. 11, the light guide plate 31
The light source 32 is, for example, as shown in FIG. 5 or 7,
If it is placed on only one of the pair of short sides of
It is preferable that the wedge shape is thinned away from the surface on which the light source 32 is located.

Alternatively, as shown in FIG. 12, the light guide plate 31
For example, when the light source 32 is arranged in each of the front light area 31a and the back light area 31b as shown in FIG. 2, FIG. 3 or FIG. It is desirable that the reflective layer 31c be an integrally molded product using a white resin. When illuminating each area, due to the reflection of the reflective layer 31c, the front light area 31a is moved to the backlight area 31b side or the backlight area 31b is operated to the front light area 31.
This is because it is possible to prevent light from leaking to the a side, improve light utilization efficiency, and reduce power consumption.

Alternatively, as shown in FIG. 13, the light guide plate 31
Are the front light area 31a and the back light area 31.
b may be molded separately and arranged in the same layer, and a reflection sheet 31d made of PET may be sandwiched between the boundary surfaces. Also by this, from the front light area 31a side to the back light area 31b side or the back light area 31b.
Side to the front light region 31a side, light leakage can be prevented, light utilization efficiency is improved, and low power consumption can be achieved.

Alternatively, as shown in FIG. 14, the light guide plate 31
Front light area 31a and back light area 31b
A slit 31e may be provided between the slits and the reflection sheet 33a bent into an L shape may be inserted into the slit 31e. This reflection sheet 33a is a folding sheet 31f.
Is bent into an L-shape, and the length of the shorter one, that is, the length of the folding ridge 31f is approximately equivalent to the thickness of the light guide plate 31, and the length of the longer one is almost equal to that of the backlight region 31b. It has a size corresponding to the length of the light guide plate 31.

Then, the folding groove 31f of the reflection sheet 33a is surely inserted into the slit 31e of the light guide plate 31, and the longer one is arranged on the upper surface of the light guide plate 31 in the backlight region 31b. With this configuration, the front light area 31a
Light or the light in the backlight region 31b is reflected by the reflection sheet 33a, so that the light utilization efficiency is good. Therefore, a low power consumption lighting device suitable for the double-sided liquid crystal display device 1 can be realized at low cost.

FIGS. 15 to 17 are perspective views for explaining the surface processing performed on the light guide plate. As shown in FIG. 15, the reflective panel 41a is provided in the front light area 31a.
The surface which does not face is provided with a serrated surface processing 35 having a slope 35a and a flat surface 35b.

FIG. 23 is an enlarged perspective view conceptually showing how light properties are converted by the light guide plate 31. Figure 2
As shown in FIG. 3, the point-like or linear light 61 a incident on the front light region 31 a from the side surface of the light guide plate 31.
Is reflected by the sloped surface 35a of the surface processing 35 to become the planar light 61b, and the planar light 61b is reflected by the reflective panel 41a.
(Refer to FIG. 1) The reflected light 61c is generated, and the surface processing 3
The light passes through the flat surface 35b of No. 5 and becomes emitted light 61d. Since the front light region 31a needs to sufficiently transmit the reflected light 61c and a sheet for controlling the light cannot be stacked, the sawtooth surface processing 35 is suitable.

On the other hand, in the backlight area 31b, a plurality of concave dots 36 are formed by molding on the surface not facing the reflection / transmission type panel 41b (see FIG. 1). At that time, the bottom surface 36a of each concave dot 36 is formed by minute irregularities and has a scattering function. Furthermore, on the surface of the backlight area 31b where the concave dots 36 are formed, the PET
A reflection sheet 33 made of metal
A light control sheet 34 such as a laminated body of a diffusion sheet and a lens sheet, a lens sheet, or a diffusion sheet is placed on the surface facing b. The point-shaped or linear-shaped light 62a that has entered the backlight region 31b from the side surface of the light guide plate 31 has a plurality of concave dots 36 that have been molded.
Are scattered by and are converted into planar light 62b directed to the reflective / transmissive panel 41b (see FIG. 1).

When the slit 31e is provided in the light guide plate 31 as shown in FIG. 14, the front light area 31 is formed.
If the surface processing 35 of a and the concave dots 36 of the backlight area 31b are molded at the same time, the number of steps is reduced and the processing is easy.

Alternatively, as shown in FIG. 16, the concave dots 3
Instead of 6, the screen printing 37 of the diffuse reflection paint is applied to the surface not facing the reflection / transmission type panel 41b (see FIG. 1).
The light guide plate 31 can also be made to have diffusivity by performing the above, and the planar light 62b facing the reflective / transmissive panel 41b can be obtained.
Is obtained. Also in this case, a laminated body of a PET reflection sheet and a lens sheet, or a lens sheet or a diffusion sheet 34 is overlaid on the surface of the backlight area 31b where the concave dots 36 are formed. Backlight area 31
Concave dots 36 and front side screen printing 37 are suitable for the back side display corresponding to b because high quality is required.

Alternatively, when importance is attached to brightness, FIG.
As shown in FIG. 3, the sawtooth surface processing 35 similar to that of the front light area 31a may be used, and the reflection sheet 33 may be overlapped on this surface. In this case, since the planar light 62d directed to the reflective / transmissive panel 41b (see FIG. 1) has no diffusivity, the surface facing the reflective / transmissive panel 41b has a dedicated optical sheet 38, for example, A PET film having a micro prism on the surface opposite to the surface facing the reflective / transmissive panel 41b is required.

FIGS. 18A and 18B are sectional views of the double-sided display type liquid crystal display panel 41. As shown in these figures, a liquid crystal material 47 is enclosed between two glass substrates, an upper glass substrate 46a and a lower glass substrate 46b. In addition,
A reflective film 48a made of silver or the like is provided on the inner surface of the lower glass substrate 46b on the reflective panel 41a side, and a reflective transmissive film 48b made of silver or the like is provided on the inner surface of the upper glass substrate 46a on the reflective transmissive panel 41b side. Will be placed. A polycarbonate retardation plate 49 is provided on the outer surface of the upper glass 46a.
b and a polarizing plate 49a made of triacetyl cellulose are sequentially laminated. The retardation plate 49b and the like may be a single layer or multiple layers. Further, in the reflective panel 41a, the reflective film 48a is formed on the inner surface of the lower glass substrate 46b, but a reflective plate may be provided on the outer surface of the lower glass substrate 46b.

As shown in FIG. 18A, when the sidelight type illumination device 30 (see FIG. 1) is turned on, the front light area 31a (see FIG. 1) is formed in the reflection type panel 41a.
The planar light 61b supplied from the reflective film 48a is reflected by the reflective film 48a, and the planar light 62b supplied from the backlight region 31b of the reflective / transmissive panel 41b is reflected / transmissive film 48.
It is transmitted by the transparency of b and is emitted as a front side display and a back side display, respectively.

On the other hand, as shown in FIG. 18B, when the external light is bright, the side light type illumination device 30 is not turned on, and the external light 63a is reflected by the reflection film 48a on the reflection type panel 41a.
Is reflected by the reflective / transmissive panel 41b due to the reflectivity of the reflective / transmissive film 48b, and becomes reflected light 63b, which is emitted as a front side display and a back side display, respectively.

FIGS. 19A and 19B are sectional views of another example of the double-sided display type liquid crystal display panel 41. As shown in these drawings, a transmissive liquid crystal display panel 41c can be used instead of the transmissive panel for display on the back side.

As shown in FIG. 19A, when the sidelight type illuminating device 30 (see FIG. 1) is turned on, the planar light 6 supplied from the backlight region 31b (see FIG. 1).
2b is transmitted by the transmissive panel 41c and emitted light 62c
Then, it is emitted as a display on the back side.

On the other hand, as shown in FIG. 19B, even when the transmissive liquid crystal is used for the back side display, when the external light is bright, the side light type illumination device 30 is not turned on and the external light 63a is emitted. Is reflected by the reflective film 48a of the reflective panel 41a to become reflected light 63b, which is emitted as a display on the front surface side.

FIG. 20 is a perspective view showing an example of the shape of a double-sided display type liquid crystal display panel. As shown in FIG. 20, the double-sided display type liquid crystal display panel 41 includes a reflection type panel 41a,
The reflective / transmissive panel 41b is an integral type, and both liquid crystal display panels are partitioned by a sealing material 48 of an ultraviolet curable resin.

FIG. 21 is a perspective view showing another example of the shape of the double-sided display type liquid crystal display panel. As shown in FIG.
The reflective panel 41a and the reflective / transmissive panel 41b may be formed in the same layer.

FIG. 22 is a perspective view of a mobile phone which is an example of a portable electronic device equipped with the double-sided display type liquid crystal display device of the present invention. In this mobile phone 70, the double-sided display type liquid crystal display device 1 shown in FIG.
It is rotatably attached to. 22, the same members as those in FIG. 1 are designated by the same reference numerals.

FIG. 22A shows a state in which the double-sided display type liquid crystal display device 1 is closed, and a display is made on the window frame 12 of the front case 11. That is, the reflective display liquid crystal panel region is in an operating state in which it can be observed from the front surface side. When the surroundings are bright, a reflective display without illumination is displayed. When the surroundings are dark, the light guide plate 31
(See FIG. 1) Front light area 31b (See FIG. 1)
It is used as a display for reflection type display with front light illumination.

FIG. 22B shows a state in which the double-sided display type liquid crystal display device 1 is rotated around the hinge portion 72 in the direction of the arrow A and opened, and the window frame 52 of the back casing 51 is covered with the window frame 52. It is supposed to be displayed. In other words, the liquid crystal panel area of the reflective display is opened, moves from the observable state to the hidden state, becomes inactive, and the liquid crystal panel area of the transflective display is opened, becomes observable and becomes active. . When the surroundings are dark, the light guide plate 31 (see FIG.
(See) is used as the backlight region 31b, and a transmissive display with backlight illumination is used for display.

The double-sided display type liquid crystal display device 1 is not limited to the case where the liquid crystal panel is a reflection type liquid crystal display and a reflection / transmission type liquid crystal panel, but is not limited to the reflection type liquid crystal panel. It can also be used when a liquid crystal panel for transmissive display forms one layer.

[0065]

As described above, according to the present invention, the light guide plate not only has the backlight function of the liquid crystal display panel,
Since it is also used as a front light function, the number of double-sided liquid crystal display devices can be further reduced compared to the conventional three-layer type double-sided liquid crystal display device equipped with a sidelight type illumination device, and the double-sided display liquid crystal display device can be made thinner. .

Further, the liquid crystal display panel according to the present invention has a reflection type display area corresponding to the front side display and a reflection transmission type display area corresponding to the back side display. Therefore, the light guide plate having one layer can be effectively used. That is, bright reflection type display can be realized by front light illumination on the front side, and bright reflection / transmission type display can be performed by backlight illumination on the back side.
In addition, when the ambient light is bright, it is not necessary to illuminate with a lighting device in the reflection type display on the front side and the reflection / transmission type display on the back side. The power consumption can be considerably reduced as compared with the display type liquid crystal display device.

Further, the liquid crystal display panel according to the present invention has a reflective display area corresponding to the front side display and a transmissive display area corresponding to the back side display. Therefore, the light guide plate having one layer can be effectively used. That is, bright reflection type display can be realized by front light illumination on the front side, and bright transmissive display can be performed by backlight illumination on the back side. In addition, when the ambient light is bright, it is a reflection type display on the front surface side, and since illumination by a lighting device is not necessary, it is compared with a conventional double-sided display type liquid crystal display device that always needs backlight illumination. , Low power consumption can be achieved.

Further, according to the double-sided display type liquid crystal display device of the present invention, the backlight illumination for the back side display and the front light illumination for the front side display can be performed by using different light sources. . This makes it possible to turn off unnecessary lighting on the display surface by illuminating when the front side display is performed or the back side display is performed when the ambient light is dark. , Low power consumption can be achieved.

Further, since the reflection function layer is provided at the boundary between the front light illumination area and the backlight illumination area of the light guide plate, it is possible to prevent light leakage from one area to the other area between the two areas. Therefore, the light utilization efficiency is improved, which is advantageous in reducing power consumption.

Further, since the folding white portion of the reflection sheet bent into an L shape is inserted into the slit provided at the boundary between the front light illuminating region and the backlight illuminating region of the light guide plate. A single reflection sheet can prevent light from leaking from one side to the other between both areas, and can improve the brightness of the backlight illumination, which is inexpensive and easy. Can be provided.

By providing such a double-sided display type liquid crystal display device in a portable electronic device, the part of the device for double-sided display can be made considerably thinner than the conventional product. Moreover, since the power consumed for display is small, the life of the built-in battery can be extended.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a double-sided display type liquid crystal display device according to the present invention.

FIG. 2 is a plan view showing an example of a positional relationship between a light guide plate and a light source.

FIG. 3 is a plan view showing another example of the positional relationship between the light guide plate and the light source.

FIG. 4 is a plan view showing another example of the positional relationship between the light guide plate and the light source.

FIG. 5 is a plan view showing another example of the positional relationship between the light guide plate and the light source.

FIG. 6 is a plan view showing another example of the positional relationship between the light guide plate and the light source.

FIG. 7 is a plan view showing another example of the positional relationship between the light guide plate and the light source.

FIG. 8 is a plan view showing another example of the positional relationship between the light guide plate and the light source.

FIG. 9 is a perspective view showing an example of the shape of a light guide plate.

FIG. 10 is a perspective view showing another example of the shape of the light guide plate.

FIG. 11 is a perspective view showing another example of the shape of the light guide plate.

FIG. 12 is a perspective view showing another example of the shape of the light guide plate.

FIG. 13 is a perspective view showing another example of the shape of the light guide plate.

FIG. 14 is a perspective view showing still another example of the shape of the light guide plate.

FIG. 15 is a perspective view for explaining an example of surface processing performed on a light guide plate.

FIG. 16 is a perspective view for explaining another example of the surface processing performed on the light guide plate.

FIG. 17 is a perspective view for explaining still another example of the surface processing performed on the light guide plate.

FIG. 18 is a cross-sectional view of a double-sided display type liquid crystal display panel, in which (a) is a front-side display using reflection type display with front light illumination, and a back-side display is backlight type reflection-transmissive display. When performing, (b) shows the case where the display on the front surface side is performed by the reflection type display by the outside light and the side surface side display is performed by the reflection and transmission type display by the outside light.

FIG. 19 is a cross-sectional view of a double-sided display type liquid crystal display panel, in which FIG. 19A shows front side display by reflection type display by front light illumination and back side display by transmissive display by backlight illumination. The case (b) shows the case where the display on the front surface side is performed by the reflection type display using external light.

FIG. 20 is a perspective view showing an example of the shape of a double-sided display type liquid crystal display panel.

FIG. 21 is a perspective view showing another example of the shape of the double-sided display type liquid crystal display panel.

22A and 22B are perspective views of an example of a mobile phone equipped with the double-sided display type liquid crystal display device according to the present invention, where FIG. 22A is a state in which a foldable display unit is closed, and FIG. Shows the opened state.

FIG. 23 is an enlarged perspective view conceptually showing how light properties are converted by a light guide plate.

FIG. 24 is a cross-sectional view of an example of a conventional double-sided display type liquid crystal display device.

[Explanation of symbols]

1 Double-sided front type liquid crystal display device 11 front enclosure 12 window frames 20 holder 30 Side light type lighting device 31 Light guide plate 31a Front light area 31b Backlight area 32 light sources 33 Reflective sheet 34 Light control sheet 35 Serrated surface processing 36 concave dots 37 Screen printing 41 Double-sided liquid crystal display panel 41a reflective panel 41b Reflective transmission type panel 41c transmissive panel 47 Liquid crystal material 48a reflective film 48b reflective / transmissive film 51 back housing 52 window frame

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02F 1/13357 G02F 1/13357 G09F 9/35 G09F 9/35 9/40 303 9/40 303 // F21Y 101: 02 F21Y 101: 02 103: 00 103: 00 F term (reference) 2H089 HA27 HA31 QA16 2H091 FA14Y FA23Z FA29X FA41X FA41Z LA11 LA17 LA18 5C094 AA10 AA15 AA22 BA43 DA02 DA08 DA11

Claims (7)

[Claims] 1. A liquid crystal display panel, and a sidelight type lighting device including a light source and a light guide plate, wherein the liquid crystal display panel and the light guide plate form a laminated body, and the laminated body has a front surface side and a back side. A double-sided display type liquid crystal display device that performs display on the surface side, wherein the liquid crystal display panel and the light guide plate are each one layer in the laminated body. 2. A liquid crystal display panel, and a sidelight type lighting device including a light source and a light guide plate, wherein the liquid crystal display panel and the light guide plate form a laminated body, and a front surface side and a back of the laminated body. In a double-sided display type liquid crystal display device that performs display on the front side, the liquid crystal display panel has a reflective display area corresponding to the front side display and a transflective display area corresponding to the back side display. The light guide plate has a region having a front light function and a region having a backlight function, the reflective display region and the region having the front light function overlap each other, the reflective transmissive display region and the A double-sided display type liquid crystal display device, characterized in that it overlaps with a region having a backlight function. 3. A liquid crystal display panel, and a sidelight type illumination device including a light source and a light guide plate, wherein the liquid crystal display panel and the light guide plate form a laminated body, and a front surface side and a back of the laminated body. In a double-sided display type liquid crystal display device that performs display on the surface side, the liquid crystal display panel has a reflective display area corresponding to the front side display and a transmissive display area corresponding to the back side display. The light guide plate has a region having the front light function and a region having the backlight function, the reflective display region and the region having the front light function overlap each other, the transmissive display region and the backlight A double-sided display type liquid crystal display device, characterized in that it overlaps with a region having a write function. 4. The sidelight type illuminating device is characterized in that a light source is separately provided for a region having a front light function and a region having a backlight function of the light guide plate. Item 4. The double-sided display type liquid crystal display device according to Item 2 or 3. 5. The double-sided display type as claimed in claim 4, wherein the light guide plate is provided with a reflection function layer at a boundary between the area having the front light function and the area having the backlight function. Liquid crystal display device. 6. A reflection sheet, which is formed by bending the light guide plate into an L shape with a folding strip corresponding to the thickness of the light guide plate, and has a slit at a boundary between a region having a front light function and a region having a back light function of the light guide plate. The double-sided display type liquid crystal according to claim 5, wherein the reflection sheet is attached to the back surface of the backlight area of the light guide plate by inserting the folding sheet of the reflection sheet into the slit. Display device. 7. A portable electronic device comprising the double-sided display type liquid crystal display device according to claim 1. Description: