JP2003279963A - Liquid crystal display device and terminal mounted with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of being miniaturized and thinned by using a light source and a light guide plate and efficiently utilizing the light from the light source, thereby performing double side display without being affected by the display of a liquid crystal panel on the opposite side. <P>SOLUTION: The liquid crystal display device comprises: a back light unit 13 for irradiating both surfaces of the light guide plate 12 with light; and the liquid crystal panels 14a and 14b, which are symmetrically arranged on both surfaces of the light guide plate 12 and in which each of first transparent substrates 15a and 15b, first polarizers 16a and 16b, first liquid crystal materials 17a and 17b, second polarizers 18a and 18b provided by bending the axial direction of the first polarizers, second transparent substrates 19a and 19b, color filters 20a and 20b, second liquid crystal materials 21a and 21b, third transparent substrates 22a and 22b, and third polarizers 23a and 23b provided by bending the axial direction of the second polarizers are laminated in this order from the light guide plate 12. The axial direction of the first polarizer 16a is bent to that of the first polarizer 16b. <P>COPYRIGHT: (C)2004,JPO

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, and more particularly to a liquid crystal display device mounted on a terminal device such as a mobile phone, PHS or PDA.

[0002]

2. Description of the Related Art Conventionally, there is a product in which a main display liquid crystal panel 117 and a sub (rear) display liquid crystal panel 121 are mounted in a terminal device such as a mobile phone, a PHS and a personal digital assistant (PDA). FIG. 12 is a side sectional view of a liquid crystal display device 110 including a main display liquid crystal panel 117 and a sub display liquid crystal panel 121. A liquid crystal unit 112 on the main display liquid crystal panel 117 side and a liquid crystal unit 113 on the sub display liquid crystal panel 121 side are separately configured with the substrate 111 interposed therebetween. The liquid crystal unit 112 on the main side
On the upper surface of the substrate 111, a main liquid crystal light source 114, a main liquid crystal light guide plate 115, a main liquid crystal optical filter 116,
It is composed of a main display liquid crystal panel and 117. on the other hand,
The liquid crystal unit on the sub side also has the same configuration as the main side.

Further, Japanese Patent Laid-Open No. 10-90678 discloses a liquid crystal display device having liquid crystal display surfaces on both front and back surfaces. A liquid crystal panel is attached to both sides of a light guide plate of a backlight unit using a cold cathode tube as a light source, so that both liquid crystal panels can be displayed.

[0004]

However, as shown in FIG.
In the above configuration, the light sources 114 and 118 and the light guide plates 115 and 11 are
A backlight unit consisting of 9 is required for each liquid crystal panel, which hinders the miniaturization and thinning of the product. Furthermore, 2
Since the two light sources 114 and 118 are required, power consumption at the time of simultaneous lighting increases.

In the liquid crystal display device disclosed in Japanese Unexamined Patent Publication No. 10-90678, the liquid crystal panels are directly attached to both surfaces of the light guide plate. Therefore, in the case of simultaneous double-sided display, the dots on the opposite liquid crystal panel are turned on / off. When turned off, transmission / reflection of the backlight light occurs, and the backlight light appears as spots. That is, the liquid crystal display of each other affects the liquid crystal display on the opposite side as a shadow, which causes display failure. Further, since the axial directions of the liquid crystal panels of each other are not described, if the axial directions of the two liquid crystal panels are the same, only light in the axial directions can be effectively used. Therefore, it is necessary to increase the light amount of the backlight in order to make the display bright, which leads to an increase in power consumption.

The present invention realizes downsizing and thinning using one light source and a light guide plate, uses light from the light source efficiently, and is not affected by the display of the liquid crystal panel on the opposite side. An object of the present invention is to provide a liquid crystal display device that can be used.

[0007]

In order to achieve the above object, a liquid crystal display device of the present invention comprises a light source and a light guide plate,
A backlight unit that emits light in both directions of the light guide plate, and a first transparent substrate, a first polarizing plate, and a first liquid crystal that are arranged symmetrically on both sides of the light guide plate and are arranged in order from the light guide plate. Material, the second polarizing plate in which the axial direction of the first polarizing plate is bent, the second transparent substrate, the second liquid crystal material, the third transparent substrate, and the third polarizing plate in which the axial direction of the second polarizing plate is bent. A liquid crystal display device comprising: a liquid crystal panel having a plurality of polarizing plates stacked together, wherein the first polarizing plate of one liquid crystal panel and the first polarizing plate of the other liquid crystal panel are bent in the axial direction. It is characterized by being

According to this structure, since the polarization directions of the light transmitted through the liquid crystal panels on both sides of the light guide plate are different, it is possible to effectively use the light that has been lost light in the past. Further, the backlights of both liquid crystal panels can be turned on at the same time, or only one side of the backlight can be turned on. Further, even when the backlight is turned off or when the backlight is shut off by the first liquid crystal material, the display by the second liquid crystal material can be visually recognized because it functions as a reflective liquid crystal. And downsizing by using one light source and light guide plate
It is possible to provide a liquid crystal display device that realizes thinning, efficiently uses light from a light source, and is capable of double-sided display that is not affected by the display of the liquid crystal panel on the opposite side.

Incidentally, in at least one of the liquid crystal panels of the liquid crystal display device, the first polarizing plate may be arranged on the light guide plate side of the first transparent substrate.

Further, in at least one of the liquid crystal panels of the liquid crystal display device, the second polarizing plate may be arranged between the second transparent substrate and the second liquid crystal material.

Further, in at least one of the liquid crystal panels of the liquid crystal display device, a third polarizing plate may be arranged between the second liquid crystal material and the third transparent substrate.

Further, in at least one of the liquid crystal panels of the liquid crystal display device, a color filter may be arranged on any surface of the second liquid crystal material.

Further, the liquid crystal display device of the present invention comprises a light source and a light guide plate, and a backlight unit for irradiating light in both directions of the light guide plate, and the light guide plate disposed symmetrically on both sides of the light guide plate. In the order of the first, the first transparent substrate, the first polarizing plate, the first liquid crystal material, the second polarizing plate in which the axial direction of the first polarizing plate is bent, the second transparent substrate, and the second polarizing plate. A third polarizing plate coaxial with the third polarizing plate, a third transparent substrate, a color filter,
A fourth polarizing plate coaxial with the third polarizing plate, a second liquid crystal material, a fifth polarizing plate in which the axial direction of the fourth polarizing plate is bent, and a fourth polarizing plate.
A transparent substrate, and a liquid crystal panel in which a fifth polarizing plate and a sixth polarizing plate coaxial with each other are stacked,
The axial direction of the first polarizing plate of one liquid crystal panel and the first polarizing plate of the other liquid crystal panel can be bent.

In the above liquid crystal display device, light is reflected by changing the polarization direction of the light between the light guide plate and the first transparent substrate or between the first transparent substrate and the first polarizing plate. An optical filter may be arranged. With this configuration, the light loss of the backlight can be reduced.

In the above liquid crystal display device, the backlight unit may be a side light type unit in which the light source is a light emitting diode array.

Further, in the liquid crystal display device, the liquid crystal panels symmetrically arranged on both surfaces of the light guide plate are controlled by one driving driver respectively, so that the liquid crystal display device is downsized by reducing the number of parts. -It can be made thinner.

The terminal equipment of the present invention is equipped with the above-mentioned liquid crystal display device.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a liquid crystal display device 1 according to the present invention.
It is a side sectional view of 0. The liquid crystal display device 10 includes a light source 11 such as a light-emitting diode array and a light guide plate 12, and a side light type backlight unit 13 that irradiates both sides of the light guide plate 12 and symmetrically arranged on both sides of the backlight unit 13. Liquid crystal panels 14a and 14b. Hereinafter, for convenience of description, the liquid crystal panel 14a side of the backlight unit 13 is referred to as a front surface side, and the liquid crystal panel 14b side of the backlight unit 13 is referred to as a rear surface side.

The liquid crystal panels 14a and 14b are arranged in order of proximity to the light guide plate 12, first transparent substrates 15a and 15b, first polarizing plates 16a and 16b, first liquid crystal materials 17a and 17b, and first.
Second polarizing plates 18a and 18b, which are obtained by bending the polarizing plates 16a and 16b in the axial direction by 90 °, and second transparent substrates 19a and 19b.
b, the color filters 20a and 20b, and the second liquid crystal material 21.
a, 21b, the third transparent substrates 22a, 22b, and the third polarizing plates 23a, 23b obtained by bending the second polarizing plates 18a, 18b by 90 ° in the axial direction. Here, the axial direction of the first polarizing plate 16a and the first polarizing plate 16b is 90 °.
It shall be bent. In the present invention, the angle at which the axial direction of the polarizing plate is bent will be described by taking a commonly used angle of 90 ° as an example, but there is no particular limitation as long as the angles are not the same.

The members having the same name do not necessarily have to have the same material and thickness, and may be selected in consideration of the material and the thickness suitable for the purpose and the cost. The members of the liquid crystal panel 14b are the liquid crystal panel 14a.
The thickness and area may be different from those of the member. With the above configuration, the first liquid crystal material 17a, 17b is used as a liquid crystal shutter for only ON / OFF control, and the second liquid crystal material 2 is used.
1a and 21b are used for displaying characters and patterns.

The above liquid crystal panel 14a or 14b
Of at least one of the first polarizing plate 16a or 1
6b may be arranged on the light guide plate 12 side of the first transparent substrate 15a or 15b.

Further, the above liquid crystal panel 14a or 14b
Of at least one of the second polarizing plate 18a or 1
8b may be arranged between the second transparent substrate 19a or 19b and the second liquid crystal material 21a or 21b.

Further, the above liquid crystal panel 14a or 14b
Of at least one of the third polarizing plate 23a or 2
3b may be arranged between the second liquid crystal material 21a or 21b and the third transparent substrate 22a or 22b.

Further, the above liquid crystal panel 14a or 14b
Of at least one of the second liquid crystal material 21a or 2
You may make it arrange | position the color filter 20a or 20b on either surface of 1b.

Further, the light guide plate 12 and the first transparent substrate 15
a, 15b, or the first transparent substrate 15a, 15b
An optical filter (not shown) that changes the polarization direction of light and reflects the light may be arranged between the first polarizing plate 16a and the first polarizing plate 16b.

FIG. 2 is a view showing the axial directions of the first to third polarizing plates in the liquid crystal display device 10. As described above, the axial direction 16c of the first polarizing plate 16a, the axial direction 18c of the second polarizing plate 18a, and the axial direction 2c of the third polarizing plate 23a.
3c is bent by 90 °, and similarly, the axial direction 16d of the first polarizing plate 16b and the axial direction 1 of the second polarizing plate 18b are the same.
8d, the axial direction 23d of the third polarizing plate 23b is bent by 90 °. Further, the axial direction 16c and the axial direction 16d are bent by 90 ° so that the polarization directions used on the front surface side and the back surface side are not the same.

Next, another liquid crystal display device in which the above-mentioned liquid crystal display device 10 is added with structural members to have a practical structure will be described. FIG. 3 is a side sectional view of another liquid crystal display device 30. The liquid crystal display device 30 includes a light source 31 such as a light emitting diode array and a light guide plate 32, and a side light type backlight unit 33 that irradiates both sides of the light guide plate 32, and is symmetrically arranged on both sides of the backlight unit 33. Liquid crystal panels 34a and 34b.
Further, the liquid crystal panels 34a and 34b are liquid crystal shutter plates 35a and 35b for transmitting / reflecting light from the light guide plate 32 by ON / OFF control and a liquid crystal display panel 36a for displaying characters and patterns in order from the light guide plate 32. , 36b. Hereinafter, for convenience of description, the liquid crystal panel 34a side of the backlight unit 33 is referred to as a front surface side, and the liquid crystal panel 34b side of the backlight unit 33 is referred to as a rear surface side.

The liquid crystal shutter plates 35a and 35b are arranged in order from the light guide plate 32 in the order of the first transparent substrates 37a and 37b and the first transparent substrates 37a and 37b.
Polarizing plates 38a, 38b, first liquid crystal materials 39a, 39
b, second polarizing plates 40a and 40b in which the axial directions of the first polarizing plates 38a and 38b are bent by 90 °, and a second transparent substrate 41.
a, 41b.

The liquid crystal display panels 36a and 36b are provided with a second polarizing plate 40 in order from the liquid crystal shutter plates 35a and 35b.
a, 40b and third polarizing plates 42a, 42b coaxial with
Third transparent substrate 43a, 43b, color filter 44
a, 44b, fourth polarizing plates 45a, 45b coaxial with the third polarizing plates 42a, 42b, second liquid crystal materials 46a, 4b.
6b, fifth polarizing plates 47a and 47b in which the axial directions of the fourth polarizing plates 45a and 45b are bent by 90 °, and a fourth transparent substrate 48.
a, 48b, fifth polarizing plates 47a, 47b, and sixth polarizing plates 49a, 49b coaxial with each other. Here, it is assumed that the axial directions of the first polarizing plate 38a and the first polarizing plate 38b are bent by 90 °.

The members having the same name do not necessarily have to use the same material and thickness, and may be selected in consideration of the material and the thickness suitable for the purpose and the cost. The members of the liquid crystal panel 34b are the liquid crystal panel 34a.
The thickness and area may be different from those of the member.

The above liquid crystal panel 34a or 34b is used.
Of at least one of the first polarizing plate 38a or 3
8b may be arranged on the light guide plate 32 side of the first transparent substrate 37a or 37b.

Further, the above liquid crystal panel 34a or 34b
Of at least one of the second polarizing plate 40a or 4
0b may be arranged between the second transparent substrate 41a or 41b and the third polarizing plate 42a or 42b.

In addition, the above liquid crystal panel 34a or 34b
Of at least one of the third polarizing plate 42a or 4
2b may be arranged between the third transparent substrate 43a or 43b and the color filter 44a or 44b, or between the color filter 44a or 44b and the fourth polarizing plate 45a or 45b.

In addition, the above liquid crystal panel 34a or 34b
For at least one of the above, the color filter 44a or 44b may be arranged between the fourth polarizing plate 45a or 45b and the fourth transparent substrate 48a or 48b.

Further, the light guide plate 32 and the first transparent substrate 37.
between a and 37b, or the first transparent substrate 37a, 37b
An optical filter (not shown) that changes the polarization direction of light and reflects the light may be disposed between the first polarizing plate 38a and the first polarizing plate 38b.

FIG. 4 is a view showing the axial directions of the first to sixth polarizing plates in the liquid crystal display device 30. As described above, the axial direction 38c of the first polarizing plate 38a, the axial direction 47c of the fifth polarizing plate 47a, and the axial direction 4c of the sixth polarizing plate 49a.
9c are the same, and the second polarizing plate 40a
The axial direction 40c, the axial direction 42c of the third polarizing plate 42a,
The axial direction 45c of the fourth polarizing plate 45a is bent 90 °. Similarly, on the back side, the axial direction 3 of the first polarizing plate 38b is 3
8d, the axial direction 47d of the fifth polarizing plate 47b, and the axial direction 49d of the sixth polarizing plate 49b are the same, whereas the axial direction 40d of the second polarizing plate 40b and the third polarizing plate 42 are the same.
b axial direction 42d, fourth polarizing plate 45b axial direction 45d
Is bent 90 °. Further, the axial direction 38c and the axial direction 38d are bent by 90 ° so that the polarization directions used on the front surface side and the back surface side are not the same.

In the liquid crystal display device 10 or 30, the structure of the portion functioning as a liquid crystal shutter is as follows.
A simple electrode structure of one electrode pair that does not have a plurality of dot matrix structures is adopted. Further, since strength is not so required, it can be made thin, and glass or resin as thin as possible can be used for the transparent substrate on which the electrodes are deposited. In addition, the polarizing plate of the present invention may be in the form of a sheet for thinning.

The operation of the liquid crystal display device of the present invention will be described below by taking the liquid crystal display device 30 as an example. To simplify the description, only the light in the axial direction 38c and the light in the axial direction 38d emitted from the light source 31 will be described. Light in the other axial directions is always reflected by the liquid crystal shutter plates 35a and 35b. Since the liquid crystal display device 10 operates in the same manner, detailed description thereof will be omitted. FIG. 5 is a diagram showing an example of a transmission state of backlight light in the liquid crystal display device 30. In FIG. 5, the liquid crystal shutter plate 35a is turned on (light transmission state), the liquid crystal display panel 36a is turned on (display state), the liquid crystal shutter 35b is turned off (total reflection state), and the liquid crystal display panel 36b is turned on (display state) or off. (Hidden state).

The light 50 emitted from the light source 31 in the axial direction 38c is emitted by the light guide plate 32 to the surface 50a.
And light 50b for irradiating the back side. And
The light 50a passes through the liquid crystal shutter plate 35a in the ON state, and is subsequently colored and displayed in color by the color filter 44a when transmitted through the liquid crystal display panel 36a in the ON state. Further, the light 50b is totally reflected by the liquid crystal shutter plate 35b having different axial directions, passes through the light guide plate 32, and is reflected by the light 50b.
As in the case of a, the liquid crystal shutter plate 35a and the liquid crystal display panel 36a are transmitted and color display is performed. In this way, the liquid crystal shutter plate 35b serves as a reflection plate for reflecting the light 50b to the front surface side.

On the other hand, the axial direction 38 emitted from the light source 31
The light 51 of d is divided by the light guide plate 32 into light 51a for irradiating the front surface side and light 51b for irradiating the rear surface side. Then, the light 51b turns off the liquid crystal shutter plate 35b.
Totally reflected by. Further, the light 51a is totally reflected by the liquid crystal shutter plate 35a having different axial directions, and the light guide plate 32 is
And the light 51b is totally reflected by the liquid crystal shutter plate 35b. In this way, the liquid crystal shutter plate 35b
Serves as a liquid crystal shutter that blocks light 51a and 51b.

Further, the liquid crystal display panel 36b in the ON state
Transmits the external light 52 from the back side. The external light 52 is totally reflected by the liquid crystal shutter plate 35b in the OFF state, and again passes through the liquid crystal display panel 36b. On the other hand, OF
The liquid crystal display panel 36b in the F state has external light 53 from the back surface.
To be totally reflected. Thus, the liquid crystal panel 34b on the rear side is
With a reflective liquid crystal-like configuration, the display of the liquid crystal display panel 36b can be visually recognized by utilizing external light.

FIG. 6 is a diagram showing an example of the state of transmission of backlight light in the liquid crystal display device 30. In FIG.
The liquid crystal shutter plate 35a is turned on (light transmission state), the liquid crystal display panel 36a is turned on (display state), the liquid crystal shutter 3
5b is ON (light transmission state), liquid crystal display panel 36b is O
N (display state).

The light 60 emitted from the light source 31 in the axial direction 38c is emitted by the light guide plate 32 to the surface 60a.
And light 60b for irradiating the back side. And
The light 60a is transmitted through the liquid crystal shutter plate 35a in the ON state, and subsequently, when transmitted through the liquid crystal display panel 36a in the ON state, colored by the color filter 44a and displayed in color. In addition, the light 60b is totally reflected by the liquid crystal shutter plate 35b having different axial directions, passes through the light guide plate 32, and passes through the light 60b.
As in the case of a, the liquid crystal shutter plate 35a and the liquid crystal display panel 36a are transmitted and color display is performed. In this way, the liquid crystal shutter plate 35b serves as a reflection plate for reflecting the light 60b to the front surface side.

On the other hand, the axial direction 38 emitted from the light source 31
The light 61 of d is divided by the light guide plate 32 into light 61a for irradiating the front surface side and light 61b for irradiating the rear surface side. Then, the light 61b is transmitted through the liquid crystal shutter plate 35b in the ON state, and subsequently, when transmitted through the liquid crystal display panel 36b in the ON state, is colored by the color filter 44b and is displayed in color. The light 61a is totally reflected by the liquid crystal shutter plate 35a having different axial directions, passes through the light guide plate 32, and is reflected by the light 6a.
Similarly to 1b, the liquid crystal shutter plate 35a and the liquid crystal display panel 36a are transmitted to display a color. In this way, the liquid crystal shutter plate 35a functions as a reflection plate for reflecting the light 61a to the front surface side.

Although an example of the transmission state of the backlight light has been described with reference to FIGS. 5 and 6, the liquid crystal shutter plate 35a,
ON / OFF of 35b and liquid crystal display panels 36a and 36b
The same applies to other combinations of states. In FIG. 7, liquid crystal shutter plates 35a and 35b and a liquid crystal display panel 36a,
The combination of ON / OFF control of 36b is shown. The combination is 9
If the liquid crystal display device 30 is mounted on a terminal device such as a mobile phone, PHS, PDA, etc., the display state can be changed according to the user's operation.

FIG. 8 is an external perspective view of the foldable portable telephone 70 equipped with the liquid crystal display device 30 in an open state. The mobile phone 70 includes a first housing 71 and a second housing 73 rotatably connected to a lower end portion of the first housing 71 by a hinge 72. The second housing 73 is It can be opened and closed with respect to the first housing 71, and the mobile phone 70 can be folded in two. FIG. 9 shows a plan view of the mobile phone 70 in a folded state.

As shown in FIGS. 8 and 9, the first casing 11 has a liquid crystal panel (front surface liquid crystal screen) 34a for displaying information on the inner surface when folded, and a first liquid crystal panel 34a when folded. A liquid crystal panel (rear liquid crystal screen) 34b that displays information on the outer surface, a protrusion 75 that presses an open / close detection switch 74, which will be described later, are provided below the liquid crystal panel 34a, and an antenna 76 is provided at the upper end. . Further, the second housing 73 is provided with an opening / closing detection switch 74 that is pressed against the protrusion 75 in the folded state, and an operation unit 77 including various keys for dial operation and the like.

In the folded state (state of FIG. 9) of the portable telephone 70, the protrusion 75 pushes the open / close detection switch 74, and the closed state of the housing is detected. On the other hand, when the second casing 73 is rotated and opened (state of FIG. 8), the protrusion 75 separates from the open / close detection switch 74, and the opened state of the casing is detected.

FIG. 10 is a block diagram showing a configuration of a part related to control of the liquid crystal display device 30 of the mobile phone 70. In addition to the liquid crystal display device 30, the mobile phone 70 includes a CPU 80 that controls the overall operation of the mobile phone 70, a front surface liquid crystal panel driver 81 that drives the liquid crystal display panel 36a and the liquid crystal shutter plate 35a, and the liquid crystal display panel 36.
b, a rear liquid crystal panel driver 82 for driving the liquid crystal shutter plate 35b, a liquid crystal controller 83 for controlling the front liquid crystal panel driver 81 and the rear liquid crystal panel driver 82, and liquid crystal panels 34a, 34b and a light source 31 are set. The memory 84 stores a control pattern and the like, a light source drive circuit 85 for driving the light source 31, and an open / close detection switch 74.

Based on the detection result of the open / close detection switch 74, the CPU 80 reads an appropriate control pattern set and registered in the memory 84, and controls the liquid crystal controller 83 and the light source drive circuit 85. LCD controller 8
Reference numeral 3 controls the front liquid crystal panel driver 81 and the rear liquid crystal panel driver 82 based on an instruction from the CPU 80.

Although the liquid crystal display panel 36a and the liquid crystal shutter plate 35a are both driven by the front surface liquid crystal panel driver 81 in FIG.
A driver (not shown) for driving a and a driver for driving the liquid crystal shutter plate 35a may be separately provided. The same applies to the rear liquid crystal panel driver 82.

Next, the operation of the mobile phone 70 will be described. FIG. 11 is a flowchart showing the operation of the mobile phone 70. When the light source 31 is turned on or the liquid crystal panels 34a and 34b are turned on due to an incoming call or a key operation in step S90, the process proceeds to step S91 and the open / closed state of the mobile phone 70 is detected based on the detection result of the open / closed detection switch 74. To judge. Step S91
If the mobile phone 70 is in the closed state in step S92, the process proceeds to step S92, and the rear liquid crystal display panel 36b is turned on.
/ Determine the OFF state.

In step S92, the liquid crystal display panel 3
If 6b is in the OFF state, the process proceeds to step S93 to turn on the liquid crystal display panel 36b, and then step S9.
Go to 5. On the other hand, when the liquid crystal display panel 36b is already in the ON state in step S92, step S95
Go to.

In step S95, it is determined whether the backlight, that is, the light source 31 is turned on or off. Step S
When the backlight is set to be on in 95, the process proceeds to step S96, the liquid crystal shutter plate 35b on the rear side is turned on, and then the process proceeds to step S97. on the other hand,
If the backlight is turned off in step S95, the process proceeds to step S97.

On the other hand, when the mobile phone 70 is in the open state in step S91, the process proceeds to step S98, and it is determined whether or not the display setting of the liquid crystal screen is set to the front side. If the display setting is not the front side, that is, the back side in step S98, the process proceeds to step S92 to perform the above process. On the other hand, if the display setting is the front side in step S98, the process proceeds to step S99 to determine the ON / OFF state of the front side liquid crystal display panel 36a.

In step S99, the liquid crystal display panel 3
If 6a is in the OFF state, the process proceeds to step S100, the liquid crystal display panel 36a is turned on, and then step S
Proceed to 101. On the other hand, if the liquid crystal display panel 36a is already in the ON state in step S99, step S
Proceed to 101.

In step S101, it is determined whether the backlight, that is, the light source 31 is turned on or off. When the backlight is set to be turned on in step S101, the process proceeds to step S102, the liquid crystal shutter plate 35a on the rear side is turned on, and then the process proceeds to step S97.
On the other hand, if the backlight is turned off in step S101, the process proceeds to step S97.

In step S97, it is determined whether or not the display on the front side and the display on the back side are switched, that is, the folded mobile phone 70 is opened (from the ON state of the liquid crystal panel 34b to the ON state of the liquid crystal display panel 36a). Switch to),
Conversely, the cellular phone 70 in the open state may be folded (from the ON state of the liquid crystal panel 34a to the ON state of the liquid crystal display panel 36b).
It is determined whether or not the state has been switched).

When the display is switched in step S97, the process returns to step S98. On the other hand, step S
When the display is not switched in 97, the process proceeds to step S103, and it is determined whether or not the backlight is on. If the backlight is off in step S103, the process ends. On the other hand, if the backlight is turned on in step S103, the process proceeds to step S104, and it is determined whether or not a predetermined time set for the lighting time has elapsed.

When the predetermined time has not elapsed in step S104, the process returns to step S97. On the other hand, when a predetermined time has passed in step S104, step S1
Go to 05 and turn off the liquid crystal shutter plates 35a and 35b.
After the state is set, the process proceeds to step S106, the backlight is turned off, and the process ends.

The liquid crystal display device of the present invention is not limited to the above embodiment, and a liquid crystal panel for display includes a segment type liquid crystal, STN liquid crystal, TN liquid crystal and the like, which is a duty-driven simple matrix type. LCD and TF
Active matrix type liquid crystal such as T liquid crystal and TFD liquid crystal can be used.

Further, the liquid crystal display device of the present invention can be used for terminal devices such as PHS, PDA and the like, in addition to mobile phones.

[0063]

According to the present invention, since the polarization directions of the light transmitted by the liquid crystal panels on both sides of the light guide plate are different, it is possible to effectively use the light that has been lost light in the past. Further, the backlights of both liquid crystal panels can be turned on at the same time, or only one side of the backlight can be turned on. Further, even when the backlight is turned off or when the backlight is shut off by the first liquid crystal material, the display by the second liquid crystal material can be visually recognized because it functions as a reflective liquid crystal. And downsizing by using one light source and light guide plate
It is possible to provide a liquid crystal display device that realizes thinning, efficiently uses light from a light source, and is capable of double-sided display that is not affected by the display of the liquid crystal panel on the opposite side.

[Brief description of drawings]

FIG. 1 is a side sectional view of a liquid crystal display device of the present invention.

FIG. 2 is a diagram showing axial directions of first to third polarizing plates in the liquid crystal display device of the present invention.

FIG. 3 is a side sectional view of another liquid crystal display device of the present invention.

FIG. 4 is a diagram showing axial directions of first to sixth polarizing plates in another liquid crystal display device of the present invention.

FIG. 5 is a diagram showing an example of a transmission state of backlight light in another liquid crystal display device of the present invention.

FIG. 6 is a diagram showing an example of a transmission state of backlight light in another liquid crystal display device of the present invention.

FIG. 7 is a diagram showing a combination of ON / OFF control of the liquid crystal shutter plate and the liquid crystal display panel of the present invention.

FIG. 8 is an external perspective view of a foldable mobile phone equipped with another liquid crystal display device of the present invention in an open state.

9 is a plan view of the mobile phone of FIG. 8 in a folded state.

FIG. 10 is a block diagram showing a configuration of a part relating to control of the liquid crystal display device of the mobile phone of the present invention.

FIG. 11 is a flowchart showing an operation of the mobile phone of the present invention.

FIG. 12 is a side sectional view of a conventional liquid crystal display device.

[Explanation of symbols]

10, 30, 110 Liquid crystal display device 11, 31, 114, 118 Light source 12, 32, 115, 119 Light guide plate 13, 33 Backlight unit 14a, 14b, 34a, 34b Liquid crystal panel 15a, 15b, 37a, 37b First Transparent substrate 16a, 16b, 38a, 38b First polarizing plate 16c, 16d, 38c, 38d Axial direction 17a, 17b, 39a, 39b of first polarizing plate First liquid crystal material 18a, 18b, 40a, 40b Second Polarizing plates 18c, 18d, 40c, 40d Axial directions 19a, 19b, 41a, 41b of second polarizing plates Second transparent substrates 20a, 20b, 44a, 44b Color filters 21a, 21b, 46a, 46b Second liquid crystal Material 22a, 22b, 43a, 43b Third transparent substrate 23a, 23b, 42a, 42b Third polarizing plate 23c, 23d, 42c, 42d Axial direction 45a, 45b of third polarizing plate Fourth polarizing plate 47a, 47b Fifth polarizing plate 48a, 48b Fourth transparent substrate 49a, 49b Sixth polarizing plate 70 Terminal device (portable device Telephone) 81 Driver for front surface liquid crystal panel (driving driver) 82 Driver for rear liquid crystal panel (driving driver)

Claims (10)

[Claims] 1. A backlight unit including a light source and a light guide plate, which irradiates light in both directions of the light guide plate, and a backlight unit arranged symmetrically on both sides of the light guide plate in the order of proximity to the light guide plate. Substrate, first polarizing plate, first liquid crystal material,
A second polarizing plate in which the first polarizing plate is bent in the axial direction, a second transparent substrate, a second liquid crystal material, a third transparent substrate, and a third polarizing plate in which the second polarizing plate is bent in the axial direction. A liquid crystal panel with stacked plates,
A liquid crystal display device comprising: a liquid crystal display device, wherein a first polarizing plate of one liquid crystal panel and a first polarizing plate of the other liquid crystal panel are bent in an axial direction. 2. The liquid crystal display device according to claim 1, wherein, for at least one of the liquid crystal panels, a first polarizing plate is arranged on the light guide plate side of a first transparent substrate. 3. The liquid crystal display according to claim 1, wherein at least one of the liquid crystal panels is provided with a second polarizing plate between a second transparent substrate and a second liquid crystal material. apparatus. 4. The at least one liquid crystal panel according to claim 1, wherein a third polarizing plate is arranged between the second liquid crystal material and the third transparent substrate. The described liquid crystal display device. 5. The liquid crystal display device according to claim 1, wherein at least one of the liquid crystal panels is provided with a color filter on any surface of the second liquid crystal material. 6. A backlight unit comprising a light source and a light guide plate, which irradiates light in both directions of the light guide plate; and a backlight unit arranged symmetrically on both sides of the light guide plate, in the order of proximity to the light guide plate. Transparent substrate, first polarizing plate, first liquid crystal material, second polarizing plate in which axial direction of the first polarizing plate is bent, second
Transparent substrate, a third polarizing plate coaxial with the second polarizing plate,
A third transparent substrate, a color filter, a fourth polarizing plate coaxial with the third polarizing plate, a second liquid crystal material, a fifth polarizing plate in which the axial direction of the fourth polarizing plate is bent, and a fourth polarizing plate. A liquid crystal panel in which a transparent substrate and a sixth polarizing plate coaxial with the fifth polarizing plate are stacked,
A liquid crystal display device comprising: a liquid crystal display device, wherein a first polarizing plate of one liquid crystal panel and a first polarizing plate of the other liquid crystal panel are bent in an axial direction. 7. An optical filter that changes the polarization direction of light and reflects the light is disposed between the light guide plate and the first transparent substrate or between the first transparent substrate and the first polarizing plate. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is a liquid crystal display device. 8. The liquid crystal display device according to claim 1, wherein the backlight unit is a side light type unit in which the light source is a light emitting diode array. 9. The liquid crystal display device according to claim 1, wherein the liquid crystal panels symmetrically arranged on both surfaces of the light guide plate are controlled by one driving driver. 10. A terminal device equipped with the liquid crystal display device according to claim 1.