JP3871590B2 - Liquid crystal display device and terminal device equipped with the same - Google Patents

Description

[0001]
BACKGROUND 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]
[Prior art]
  Conventionally, there are products 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 the liquid crystal display device 110 including the main display liquid crystal panel 117 and the 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 main-side liquid crystal unit 112 includes a main liquid crystal light source 114, a main liquid crystal light guide plate 115, a main liquid crystal optical filter 116, a main display liquid crystal panel on the upper surface of the substrate 111.117Consists of On the other hand, the sub liquid crystal unit has the same configuration as the main side.
[0003]
Japanese Patent Application Laid-Open No. 10-90678 discloses a liquid crystal display device having a liquid crystal display surface on both the front and back surfaces. A liquid crystal panel is bonded to both sides of a light guide plate of a backlight unit using a cold cathode tube as a light source, thereby enabling display of both liquid crystal panels.
[0004]
[Problems to be solved by the invention]
However, in the configuration of FIG. 12, a backlight unit including the light sources 114 and 118 and the light guide plates 115 and 119 is required for each liquid crystal panel, which hinders downsizing and thinning of the product. Further, since two light sources 114 and 118 are required, power consumption during simultaneous lighting increases.
[0005]
Further, in the liquid crystal display device disclosed in Japanese Patent Laid-Open No. 10-90678, the liquid crystal panel is directly bonded to both sides of the light guide plate. Therefore, in the case of double-sided simultaneous display, ON / OFF of the dots on the opposite side liquid crystal panel Transmission / reflection of the backlight light occurs, and the backlight light appears as spots. That is, the liquid crystal display of each other influences the liquid crystal display on the opposite side as a shadow, causing a display defect. Further, since the axial directions of the liquid crystal panels are not described, when the axial directions of the two liquid crystal panels are the same, only light in the axial direction can be used effectively. Therefore, it is necessary to increase the light amount of the backlight in order to brighten the display, leading to an increase in power consumption.
[0006]
The present invention realizes downsizing and thinning by using one light source and a light guide plate, efficiently utilizing light from the light source, and capable of double-sided display without being affected by the display of the opposite liquid crystal panel. An object is to provide a display device.
[0007]
[Means for Solving the Problems]
  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, and is disposed symmetrically on both sides of the light guide plate, a backlight unit that irradiates light in both directions of the light guide plate, In order from the light guide plate, the first transparent substrate, the first polarizing plate, the first liquid crystal material, the second polarizing plate obtained by bending the axial direction of the first polarizing plate, the second transparent substrate, the second A liquid crystal display device comprising: a liquid crystal material, a third transparent substrate, and a liquid crystal panel on which a third polarizing plate obtained by bending the axial direction of the second polarizing plate is stacked. PolarizerAnd othersDirection of the liquid crystal panel with the first polarizing plate, The axial direction of the second polarizing plate of one liquid crystal panel and the second polarizing plate of the other liquid crystal panel, and the third polarizing plate of one liquid crystal panel and the third polarizing plate of the other liquid crystal panel The axial direction of each is 90 °It is bent.
[0008]
According to this configuration, since the polarization direction of the light transmitted through the liquid crystal panels on both sides of the light guide plate is different, the light that has conventionally been lost light can be used effectively. Also, the backlights of both liquid crystal panels can be turned on simultaneously, 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. A liquid crystal display device that can be reduced in size and thickness by using one light source and a light guide plate, can efficiently use light from the light source, and can be displayed on both sides without being affected by the display of the opposite liquid crystal panel. Can be provided.
[0009]
Note that the first polarizing plate may be arranged on the light guide plate side of the first transparent substrate for at least one of the liquid crystal panels of the liquid crystal display device.
[0010]
Further, for at least one of the liquid crystal panels of the liquid crystal display device, a second polarizing plate may be disposed between the second transparent substrate and the second liquid crystal material.
[0011]
In addition, for at least one of the liquid crystal panels of the liquid crystal display device, a third polarizing plate may be disposed between the second liquid crystal material and the third transparent substrate.
[0012]
In addition, for at least one of the liquid crystal panels of the liquid crystal display device, a color filter may be disposed on any surface of the second liquid crystal material.
[0013]
  The liquid crystal display device of the present invention includes a light source and a light guide plate, and is arranged symmetrically on both sides of the light guide plate with a backlight unit that irradiates light in both directions of the light guide plate, in order from the light guide plate. , A first transparent substrate, a first polarizing plate, a first liquid crystal material, a second polarizing plate obtained by bending the axial direction of the first polarizing plate, a second transparent substrate, a coaxial direction with the second polarizing plate The third polarizing plate, the third transparent substrate, the color filter, the fourth polarizing plate coaxial with the third polarizing plate, the second liquid crystal material, and the fifth polarizing plate bent in the axial direction. A polarizing plate, a fourth transparent substrate, and a liquid crystal panel in which a fifth polarizing plate and a sixth polarizing plate in the coaxial direction are stacked, and the first polarizing plate of one liquid crystal panel BoardAnd othersDirection of the liquid crystal panel with the first polarizing plateThe axial direction of the second polarizing plate of one liquid crystal panel and the second polarizing plate of the other liquid crystal panel, the third polarizing plate of one liquid crystal panel and the third polarizing plate of the other liquid crystal panel Axial direction, axial direction of the fourth polarizing plate of one liquid crystal panel and the fourth polarizing plate of the other liquid crystal panel, fifth polarizing plate of one liquid crystal panel and fifth polarizing plate of the other liquid crystal panel And the axial direction of the sixth polarizing plate of one liquid crystal panel and the sixth polarizing plate of the other liquid crystal panel are both 90 °It can be set as the structure bent.
[0015]
In the liquid crystal display device, a side light type unit in which the light source is a light emitting diode array can be adopted as the backlight unit.
[0016]
Further, in the liquid crystal display device, the liquid crystal panels arranged symmetrically on both surfaces of the light guide plate are controlled by a single driving driver, thereby reducing the number of components and reducing the thickness of the liquid crystal display device. Is possible.
[0017]
The terminal device of the present invention is equipped with the liquid crystal display device.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a side sectional view of a liquid crystal display device 10 of the present invention. 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 is disposed symmetrically on both sides of the backlight unit 13 and a sidelight type backlight unit 13 that irradiates in both directions of the light guide plate 12. Liquid crystal panels 14a and 14b. Hereinafter, for convenience of explanation, the liquid crystal panel 14a side of the backlight unit 13 is referred to as a front side, and the liquid crystal panel 14b side of the backlight unit 13 is referred to as a back side.
[0019]
  The liquid crystal panels 14a and 14b are arranged in the order close to the light guide plate 12, and the axes of the first transparent substrates 15a and 15b, the first polarizing plates 16a and 16b, the first liquid crystal materials 17a and 17b, and the first polarizing plates 16a and 16b. Second polarizing plates 18a and 18b whose directions are bent by 90 °, second transparent substrates 19a and 19b, color filters 20a and 20b, second liquid crystal materials 21a and 21b, third transparent substrates 22a and 22b, second The third polarizing plates 23a and 23b, in which the axial directions of the polarizing plates 18a and 18b are bent by 90 °, are overlapped. Here, it is assumed that the axial directions of the first polarizing plate 16a and the first polarizing plate 16b are bent by 90 °.The
[0020]
In addition, it is not always necessary to use members having the same name and thickness as described above, and the members having the same name and thickness may be selected in consideration of the cost and the material and thickness suitable for the application. Moreover, the thickness and area of the liquid crystal panel 14b may be different from those of the liquid crystal panel 14a. In the above configuration, the first liquid crystal materials 17a and 17b are used as liquid crystal shutters for ON / OFF control only, and the second liquid crystal materials 21a and 21b are used for displaying characters and symbols.
[0021]
For at least one of the liquid crystal panels 14a or 14b, the first polarizing plate 16a or 16b may be disposed on the light guide plate 12 side of the first transparent substrate 15a or 15b.
[0022]
Further, for at least one of the liquid crystal panels 14a or 14b, the second polarizing plate 18a or 18b may be disposed between the second transparent substrate 19a or 19b and the second liquid crystal material 21a or 21b. Good.
[0023]
Further, for at least one of the liquid crystal panels 14a or 14b, the third polarizing plate 23a or 23b may be disposed between the second liquid crystal material 21a or 21b and the third transparent substrate 22a or 22b. Good.
[0024]
Further, for at least one of the liquid crystal panels 14a or 14b, the color filter 20a or 20b may be disposed on either surface of the second liquid crystal material 21a or 21b.
[0025]
Further, the light is reflected by changing the polarization direction of light between the light guide plate 12 and the first transparent substrates 15a and 15b or between the first transparent substrates 15a and 15b and the first polarizing plates 16a and 16b. An optical filter (not shown) may be arranged.
[0026]
FIG. 2 is a diagram illustrating 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 23c of the third polarizing plate 23a are bent by 90 °. The axial direction 16d of the polarizing plate 16b, the axial direction 18d of the second polarizing plate 18b, and the axial direction 23d of the third polarizing plate 23b are 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 side and the back side are not the same.
[0027]
Next, another liquid crystal display device in which constituent members are added to the liquid crystal display device 10 to make a practical configuration 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 is disposed symmetrically on both sides of the backlight unit 33 and a sidelight type backlight unit 33 that irradiates in both directions of the light guide plate 32. Liquid crystal panels 34a and 34b. Further, the liquid crystal panels 34a and 34b are arranged in the order close to the light guide plate 32, and liquid crystal shutter plates 35a and 35b that transmit / reflect light from the light guide plate 32 by ON / OFF control, and a liquid crystal display panel 36a for displaying characters and symbols. , 36b. Hereinafter, for convenience of explanation, the liquid crystal panel 34a side of the backlight unit 33 is referred to as a front side, and the liquid crystal panel 34b side of the backlight unit 33 is referred to as a back side.
[0028]
The liquid crystal shutter plates 35a and 35b are arranged in order of the light guide plate 32 in order of the first transparent substrates 37a and 37b, the first polarizing plates 38a and 38b, the first liquid crystal materials 39a and 39b, and the first polarizing plates 38a and 38b. It comprises second polarizing plates 40a and 40b bent in the axial direction by 90 ° and second transparent substrates 41a and 41b.
[0029]
The liquid crystal display panels 36a and 36b are arranged in the order close to the liquid crystal shutter plates 35a and 35b, the third polarizing plates 42a and 42b coaxial with the second polarizing plates 40a and 40b, the third transparent substrates 43a and 43b, and the color filters 44a. 44b, the fourth polarizing plates 45a and 45b coaxial with the third polarizing plates 42a and 42b, the second liquid crystal materials 46a and 46b, and the fourth polarizing plates 45a and 45b are bent by 90 °. The fifth polarizing plates 47a and 47b, the fourth transparent substrates 48a and 48b, the fifth polarizing plates 47a and 47b, and the sixth polarizing plates 49a and 49b in the coaxial direction are overlapped. Here, it is assumed that the axial directions of the first polarizing plate 38a and the first polarizing plate 38b are bent by 90 °.
[0030]
In addition, it is not always necessary to use members having the same name and thickness as described above, and the members having the same name and thickness may be selected in consideration of the cost and the material and thickness suitable for the application. Moreover, the thickness and area of the liquid crystal panel 34b may be different from those of the liquid crystal panel 34a.
[0031]
For at least one of the liquid crystal panels 34a or 34b, the first polarizing plate 38a or 38b may be disposed on the light guide plate 32 side of the first transparent substrate 37a or 37b.
[0032]
Further, for at least one of the liquid crystal panels 34a or 34b, the second polarizing plate 40a or 40b may be disposed between the second transparent substrate 41a or 41b and the third polarizing plate 42a or 42b. Good.
[0033]
Further, for at least one of the liquid crystal panels 34a or 34b, the third polarizing plate 42a or 42b is provided between the third transparent substrate 43a or 43b and the color filter 44a or 44b, and the color filter 44a or 44b and the fourth liquid crystal panel 34a or 34b. You may make it arrange | position between either of the polarizing plates 45a or 45b.
[0034]
Further, for at least one of the liquid crystal panels 34a or 34b, the color filter 44a or 44b may be disposed between the fourth polarizing plate 45a or 45b and the fourth transparent substrate 48a or 48b.
[0035]
Further, the light is reflected by changing the polarization direction of light between the light guide plate 32 and the first transparent substrates 37a and 37b or between the first transparent substrates 37a and 37b and the first polarizing plates 38a and 38b. An optical filter (not shown) may be arranged.
[0036]
FIG. 4 is a diagram illustrating 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 49c of the sixth polarizing plate 49a are the same. The axial direction 40c of the plate 40a, the axial direction 42c of the third polarizing plate 42a, and the axial direction 45c of the fourth polarizing plate 45a are bent by 90 °. Similarly, on the back side, the axial direction 38d of the first polarizing plate 38b, the axial direction 47d of the fifth polarizing plate 47b, and the axial direction 49d of the sixth polarizing plate 49b are the same. The axial direction 40d of the polarizing plate 40b, the axial direction 42d of the third polarizing plate 42b, and the axial direction 45d of the fourth polarizing plate 45b are bent by 90 °. Furthermore, the axial direction 38c and the axial direction 38d are bent by 90 ° so that the polarization directions used on the front side and the back side are not the same.
[0037]
In the liquid crystal display device 10 or 30, the structure of the portion functioning as the liquid crystal shutter adopts a simple electrode structure of one electrode pair that does not take a plurality of dot matrix structures. In addition, since strength is not so required, it can be thinned, and glass or resin as thin as possible can be used for the transparent substrate on which the electrode is deposited. Moreover, the polarizing plate of this invention can use a sheet-like thing for thickness reduction.
[0038]
Hereinafter, the operation of the liquid crystal display device of the present invention will be described using the liquid crystal display device 30 as an example. For the sake of simplicity, 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. The other axial light 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 is omitted. FIG. 5 is a diagram illustrating an example of a backlight light transmission state 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).
[0039]
The light 50 in the axial direction 38c emitted from the light source 31 is divided into light 50a irradiated on the front side and light 50b irradiated on the back side by the light guide plate 32. Then, the light 50a is transmitted through the liquid crystal shutter plate 35a in the ON state, and is subsequently colored by the color filter 44a when being transmitted through the liquid crystal display panel 36a in the ON state. The light 50b is totally reflected by the liquid crystal shutter plate 35b having different axial directions, passes through the light guide plate 32, passes through the liquid crystal shutter plate 35a and the liquid crystal display panel 36a, and is displayed in color. As described above, the liquid crystal shutter plate 35b serves as a reflection plate for reflecting the light 50b to the surface side.
[0040]
On the other hand, the light 51 in the axial direction 38d emitted from the light source 31 is divided into light 51a irradiated on the front side and light 51b irradiated on the back side by the light guide plate 32. The light 51b is totally reflected by the liquid crystal shutter plate 35b in the OFF state. The light 51a is totally reflected by the liquid crystal shutter plate 35a having different axial directions, passes through the light guide plate 32, and is totally reflected by the liquid crystal shutter plate 35b in the same manner as the light 51b. Thus, the liquid crystal shutter plate 35b serves as a liquid crystal shutter that blocks the light 51a and 51b.
[0041]
Further, the liquid crystal display panel 36b in the ON state transmits the external light 52 from the back side. This external light 52 is totally reflected by the liquid crystal shutter plate 35b in the OFF state, and passes through the liquid crystal display panel 36b again. On the other hand, the liquid crystal display panel 36b in the OFF state totally reflects the external light 53 from the back surface. As described above, the liquid crystal panel 34b on the back side can visually recognize the display of the liquid crystal display panel 36b by using external light due to the reflective liquid crystal structure.
[0042]
FIG. 6 is a diagram illustrating an example of a backlight transmission state in the liquid crystal display device 30. In FIG. 6, 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 on (light transmission state), and the liquid crystal display panel 36b is turned on (display state). .
[0043]
The light 60 in the axial direction 38c emitted from the light source 31 is divided into light 60a irradiated on the front side and light 60b irradiated on the back side by the light guide plate 32. Then, the light 60a is transmitted through the liquid crystal shutter plate 35a in the ON state, and is subsequently colored by the color filter 44a when being transmitted through the liquid crystal display panel 36a in the ON state. The light 60b is totally reflected by the liquid crystal shutter plate 35b having different axial directions, passes through the light guide plate 32, passes through the liquid crystal shutter plate 35a and the liquid crystal display panel 36a, and is displayed in color. As described above, the liquid crystal shutter plate 35b serves as a reflection plate for reflecting the light 60b to the surface side.
[0044]
On the other hand, the light 61 in the axial direction 38d emitted from the light source 31 is divided by the light guide plate 32 into light 61a irradiated on the front side and light 61b irradiated on the back side. The light 61b is transmitted through the liquid crystal shutter plate 35b in the ON state, and is subsequently colored by the color filter 44b when transmitted through the liquid crystal display panel 36b in the ON state. Further, the light 61a is totally reflected by the liquid crystal shutter plate 35a having different axial directions, passes through the light guide plate 32, passes through the liquid crystal shutter plate 35a and the liquid crystal display panel 36a in the same manner as the light 61b, and is displayed in color. In this way, the liquid crystal shutter plate 35a serves as a reflection plate for reflecting the light 61a to the surface side.
[0045]
Although an example of the backlight transmission state has been described with reference to FIGS. 5 and 6, the same applies to other combinations of ON / OFF states of the liquid crystal shutter plates 35a and 35b and the liquid crystal display panels 36a and 36b. FIG. 7 shows a combination of ON / OFF control of the liquid crystal shutter plates 35a and 35b and the liquid crystal display panels 36a and 36b. There are nine combinations. When this liquid crystal display device 30 is mounted on a terminal device such as a mobile phone, PHS, or PDA, the display state can be changed in response to a user operation.
[0046]
FIG. 8 is an external perspective view of a state in which the foldable mobile phone 70 on which the liquid crystal display device 30 is mounted is opened. The cellular phone 70 includes a first casing 71 and a second casing 73 that is pivotally connected to a lower end portion of the first casing 71 by a hinge 72. The first casing 71 can be opened and closed, and the mobile phone 70 can be folded in two. FIG. 9 shows a plan view of the cellular phone 70 in a folded state.
[0047]
  As shown in FIGS. 8 and 9, the first housing71Includes a liquid crystal panel (front liquid crystal screen) 34a that displays information on the inner surface when folded, a liquid crystal panel (rear liquid crystal screen) 34b that displays information on the outer surface when folded, and a liquid crystal A protrusion 75 for pressing an open / close detection switch 74 described later is provided at the lower part of the panel 34a, and an antenna 76 is provided at the upper end. In addition, the second casing 73 is provided with an open / close detection switch 74 that is pressed by the protrusion 75 in a folded state, and an operation unit 77 that includes various keys for performing dial operations and the like.
[0048]
In the cellular phone 70, when the cellular phone 70 is folded (the state shown in FIG. 9), the projection 75 is in a state of pressing 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 (the state shown in FIG. 8), the protrusion 75 is separated from the open / close detection switch 74, and the open state of the casing is detected.
[0049]
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 operation of the entire mobile phone 70, a surface liquid crystal panel driver 81 that drives the liquid crystal display panel 36a and the liquid crystal shutter plate 35a, a liquid crystal display panel 36b, The rear liquid crystal panel driver 82 for driving the liquid crystal shutter plate 35b, the liquid crystal controller 83 for controlling the front surface liquid crystal panel driver 81 and the rear liquid crystal panel driver 82, and the control patterns set for the liquid crystal panels 34a, 34b and the light source 31. And the like, a light source drive circuit 85 for driving the light source 31, and an open / close detection switch 74.
[0050]
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. The liquid crystal controller 83 controls the front liquid crystal panel driver 81 and the rear liquid crystal panel driver 82 based on a command from the CPU 80.
[0051]
In FIG. 10, the front surface liquid crystal panel driver 81 drives both the liquid crystal display panel 36a and the liquid crystal shutter plate 35a. However, the driver (not shown) that drives the liquid crystal display panel 36a and the liquid crystal shutter plate 35a are driven. You may provide the driver to perform separately. The same applies to the rear liquid crystal panel driver 82.
[0052]
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 by an incoming call or key operation in step S90, the process proceeds to step S91, and the open / close state of the mobile phone 70 is determined based on the detection result of the open / close detection switch 74. Judging. If the mobile phone 70 is in the closed state in step S91, the process proceeds to step S92 to determine the ON / OFF state of the liquid crystal display panel 36b on the back side.
[0053]
If the liquid crystal display panel 36b is in the OFF state in step S92, the process proceeds to step S93 to turn on the liquid crystal display panel 36b and then proceeds to step S95. On the other hand, if the liquid crystal display panel 36b is already in the ON state in step S92, the process proceeds to step S95.
[0054]
In step S95, a setting state of turning on / off the backlight, that is, the light source 31 is determined. If the backlight is set to light in step S95, the process proceeds to step S96 to turn on the liquid crystal shutter plate 35b on the back side, and then proceeds to step S97. On the other hand, if the backlight is set to be turned off in step S95, the process proceeds to step S97.
[0055]
On the other hand, if the mobile phone 70 is in the open state in step S91, the process proceeds to step S98 to determine whether or not the display setting of the liquid crystal screen is set to the front side. If the display setting is not on the front side in step S98, that is, if it is on the back side, the process proceeds to step S92 and the above processing is performed. 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.
[0056]
If the liquid crystal display panel 36a is in the OFF state in step S99, the process proceeds to step S100, the liquid crystal display panel 36a is turned on, and then the process proceeds to step S101. On the other hand, if the liquid crystal display panel 36a is already in the ON state in step S99, the process proceeds to step S101.
[0057]
In step S101, a setting state of turning on / off the backlight, that is, the light source 31, is determined. If the backlight is set to light in step S101, the process proceeds to step S102 to turn on the liquid crystal shutter plate 35a on the back side, and then proceeds to step S97. On the other hand, if the backlight is set to be turned off in step S101, the process proceeds to step S97.
[0058]
In step S97, whether or not the display on the front side and the back side has been switched, that is, the cellular phone 70 in the folded state is opened (switching from the ON state of the liquid crystal panel 34b to the ON state of the liquid crystal display panel 36a). On the contrary, it is determined whether or not the cellular phone 70 in the open state has been folded (switched from the ON state of the liquid crystal panel 34a to the ON state of the liquid crystal display panel 36b).
[0059]
If the display is switched in step S97, the process returns to step S98. On the other hand, when the display is not switched in step S97, the process proceeds to step S103, and it is determined whether or not the backlight is lit. 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.
[0060]
If the predetermined time has not elapsed in step S104, the process returns to step S97. On the other hand, when a predetermined time has elapsed in step S104, the process proceeds to step S105, the liquid crystal shutter plates 35a, 35b are turned off, the process proceeds to step S106, the backlight is turned off, and the process ends.
[0061]
Note that the liquid crystal display device of the present invention is not limited to the above-described embodiment, and a liquid crystal panel for display includes duty-driven simple matrix liquid crystal such as segment liquid crystal, STN liquid crystal, and TN liquid crystal. An active matrix type liquid crystal such as a TFT liquid crystal or a TFD liquid crystal can be used.
[0062]
The liquid crystal display device of the present invention can be used for terminal devices such as PHS and PDA in addition to mobile phones.
[0063]
【The invention's effect】
According to the present invention, since the polarization directions of the light transmitted through the liquid crystal panels on both sides of the light guide plate are different, the light that has conventionally been lost light can be used effectively. Also, the backlights of both liquid crystal panels can be turned on simultaneously, 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. A liquid crystal display device that can be reduced in size and thickness by using one light source and a light guide plate, can efficiently use light from the light source, and can be displayed on both sides without being affected by the display of the opposite liquid crystal panel. Can be provided.
[Brief description of the 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 illustrating an example of a backlight transmission state in another liquid crystal display device of the present invention.
FIG. 6 is a diagram illustrating an example of a state of transmission of backlight 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 state in which a foldable mobile phone equipped with another liquid crystal display device of the present invention is opened.
9 is a plan view of the cellular phone of FIG. 8 in a folded state.
FIG. 10 is a block diagram showing a configuration of a part related to control of the liquid crystal display device of the mobile phone of the present invention.
FIG. 11 is a flowchart showing the 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 of the first polarizing plate
17a, 17b, 39a, 39b First liquid crystal material
18a, 18b, 40a, 40b Second polarizing plate
18c, 18d, 40c, 40d Axial direction of second polarizing plate
19a, 19b, 41a, 41b Second transparent substrate
20a, 20b, 44a, 44b Color filter
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 of third polarizing plate
45a, 45b Fourth polarizing plate
47a, 47b fifth polarizing plate
48a, 48b Fourth transparent substrate
49a, 49b Sixth polarizing plate
70 Terminal equipment (mobile phone)
81 Front LCD panel driver (Driver driver)
82 Rear LCD panel driver (Driver driver)

Claims (9)

A backlight unit comprising a light source and a light guide plate, and irradiating light in both directions of the light guide plate;
A second arrangement in which the first transparent substrate, the first polarizing plate, the first liquid crystal material, and the first polarizing plate are bent in the axial direction in the order close to the light guide plate. A liquid crystal display device comprising: a polarizing plate, a second transparent substrate, a second liquid crystal material, a third transparent substrate, and a liquid crystal panel on which a third polarizing plate bent in the axial direction of the second polarizing plate is stacked. Because
First polarizing plate and the first axial direction between the polarizing plate of the other hand the liquid crystal panel of one of the liquid crystal panel,
The axial direction of the second polarizing plate of one liquid crystal panel and the second polarizing plate of the other liquid crystal panel, and the third polarizing plate of one liquid crystal panel and the third polarizing plate of the other liquid crystal panel A liquid crystal display device characterized in that both axial directions are bent by 90 ° .   The liquid crystal display device according to claim 1, wherein the first polarizing plate is disposed on the light guide plate side of the first transparent substrate for at least one of the liquid crystal panels.   3. The liquid crystal display device according to claim 1, wherein the second polarizing plate is disposed between the second transparent substrate and the second liquid crystal material for at least one of the liquid crystal panels.   4. The liquid crystal display device according to claim 1, wherein a third polarizing plate is disposed between the second liquid crystal material and the third transparent substrate for at least one of the liquid crystal panels. 5. .   5. The liquid crystal display device according to claim 1, wherein a color filter is disposed on any surface of the second liquid crystal material for at least one of the liquid crystal panels. A backlight unit comprising a light source and a light guide plate, and irradiating light in both directions of the light guide plate;
Secondly arranged in plane symmetry on both surfaces of the light guide plate and bent in the axial direction of the first transparent substrate, the first polarizing plate, the first liquid crystal material, and the first polarizing plate in the order close to the light guide plate. Polarizing plate, second transparent substrate, third polarizing plate coaxial with the second polarizing plate, third transparent substrate, color filter, fourth polarizing plate coaxial with the third polarizing plate, second A second liquid crystal material, a fifth polarizing plate in which the axial direction of the fourth polarizing plate is bent, a fourth transparent substrate, and a liquid crystal panel in which a fifth polarizing plate and a sixth polarizing plate in the coaxial direction are stacked. A liquid crystal display device comprising:
First polarizing plate and the first axial direction between the polarizing plate of the other hand the liquid crystal panel of one of the liquid crystal panel,
The axial direction of the second polarizing plate of one liquid crystal panel and the second polarizing plate of the other liquid crystal panel, the axis of the third polarizing plate of one liquid crystal panel and the third polarizing plate of the other liquid crystal panel Direction, the axial direction of the fourth polarizing plate of one liquid crystal panel and the fourth polarizing plate of the other liquid crystal panel, the fifth polarizing plate of one liquid crystal panel, and the fifth polarizing plate of the other liquid crystal panel And the sixth polarizing plate of one liquid crystal panel and the sixth polarizing plate of the other liquid crystal panel are both bent by 90 ° . The backlight unit, a liquid crystal display device according to any one of claims 1 to 6, characterized in that said light source is a unit of a side light type and a light emitting diode array. The liquid crystal panel disposed symmetrically on both sides of the light guide plate, a liquid crystal display device according to any one of claims 1 to 7, characterized in that it is controlled by the respective one of the driver. The terminal device carrying the liquid crystal display device in any one of Claims 1-8 .

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