JP2005092046A - Electric optical device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrooptical device which attains a double-sided display using one display panel. <P>SOLUTION: The electrooptical device can be made into a transflective liquid crystal display device using a liquid crystal display panel having liquid crystal charged between, for example, a couple of substrates. Polarizing plates are fitted to external surfaces of the electrooptical panel respectively and front light units as light sources are provided on the external surfaces respectively. Consequently, when the electrooptical panel is viewed from one surface side, the front light unit on the same side is turned on to perform reflection display and the front light unit on the opposite side is turned on to perform transmission display. Further, even when the electrooptical panel is viewed from the other surface side, the front light unit on the opposite side is turned on to obtain transmission display. Both-sided display, therefore, becomes possible by a combination of the couple of front units provided on both the surface sides. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electro-optical device such as a liquid crystal display device, and more particularly to an electro-optical device capable of double-sided display.

  In portable information terminals such as mobile phones and PDAs (Personal Digital Assistants), lightweight and small liquid crystal display devices are often used as display devices. In recent years, a foldable mobile phone or the like that can display on both sides is known. That is, the display unit can be opened and closed by a movable mechanism such as a hinge type with respect to a main body provided with various operation buttons. The display unit is provided with a liquid crystal display section on the inner surface facing the operation button surface of the main body and on the outer surface opposite to the inner surface. In a normal use state (that is, a state where the display unit is opened), the liquid crystal display section on the inner surface side is exposed together with various operation buttons. On the other hand, when the cellular phone is folded (that is, the display panel unit is closed), only the liquid crystal display unit on the outer surface side is exposed.

  In such a double-sided display type mobile phone, a pair of display panels are housed back-to-back in the display panel unit, so that the mobile phone itself becomes thicker. In addition, since a drive circuit for performing display control, a display data processing circuit, and the like are separately required, the configuration is complicated, and it is difficult to reduce the size and thickness of the apparatus.

  SUMMARY An advantage of some aspects of the invention is that it provides an electro-optical device capable of double-sided display with a single display panel.

  In one aspect of the present invention, an electro-optical device includes an electro-optical panel in which an electro-optical material is sandwiched between a pair of substrates, a pair of polarizing plates attached to the outer surface of each substrate, and the pair of polarizations. A pair of front light units attached to the outer surface of the plate.

  The electro-optical device can be a liquid crystal display device using a liquid crystal display panel in which liquid crystal is sealed between a pair of substrates, for example. A polarizing plate is attached to each outer surface of the electro-optical panel, and a front light unit as a light source is provided on each outer surface. As a result, bright display is possible when viewed from any surface side of the electro-optical panel. Therefore, double-sided display is possible by combining one electro-optical panel and a pair of front light units provided on both sides thereof.

  In the electro-optical panel, a reflective film having a plurality of openings can be provided on one of the substrates. Accordingly, when viewed from one surface side of the electro-optical panel, the front light unit on the same side can be turned on to perform bright reflective display, and the front light unit on the opposite side can be turned on to perform transmissive display. be able to. Also, when viewed from the other surface side of the electro-optical panel, transmissive display can be performed by turning on the front light unit on the opposite side. Further, even when both front light units are turned off, reflection display using natural light is possible.

  In one aspect of the electro-optical device, the front light unit on the substrate side opposite to the substrate on which the reflective film is provided has a smaller illumination area than the front light unit on the substrate side on which the reflective film is provided. be able to. Accordingly, it is possible to provide an electro-optical device having display areas with different sizes on both sides.

  In another aspect of the electro-optical device, the front light unit on the substrate side opposite to the substrate on which the reflective film is provided has an illumination area that is larger than that on the substrate side on which the reflective film is provided. It can be constituted by a plurality of small front light units.

  In this aspect, the front light unit on one surface side is configured by a combination of a plurality of front light units, so that all front light units can be turned on to display the entire surface, and some front lights can be displayed. Only the unit can be turned on to display a small display area without wasting power consumption.

  In another aspect of the present invention, an electronic apparatus includes a main body, a display unit attached to the main body so as to be openable and closable, and an electro-optical device provided in the display unit. Includes an electro-optic panel having an electro-optic material sandwiched between a pair of substrates, a pair of polarizing plates affixed to the outer surface of each substrate, and a pair of fronts attached to the outer surfaces of the pair of polarizing plates. A light unit, wherein one of the front light units is located on an outer surface exposed to the outside with the display unit closed, and the other of the front light units is an inner surface exposed with the display unit open The electro-optical device is accommodated in the display unit so as to be positioned at the position.

  The electronic device can be, for example, a foldable mobile phone capable of double-sided display, and generally includes a main body provided with operation buttons and a display unit provided openable and closable with respect to the main body. And an electro-optical device such as a liquid crystal display device is accommodated in the display unit. The electro-optical device is provided with a pair of polarizing plates on the outer surface of an electro-optical panel such as a liquid crystal display panel, and a pair of front light units on the outer surface. The desired surface side image is displayed by the lighting control of the front light unit. Specifically, only the outer surface of the display unit is exposed when the display unit is closed (that is, folded), and the inner surface of the display unit is also exposed when the display unit is opened (that is, the normal use state). . Therefore, the user can see the display screen in any state.

  In one aspect of the electronic apparatus, the control unit turns off both the pair of front light units when the display unit is closed and turns on the front light unit located on the outer surface side when the display unit is opened. A part can be further provided. Thereby, in the folded state, only the reflective display by natural light can be performed by the display unit on the outer surface side, and the power consumption can be reduced. On the other hand, in the normal use state, the display unit on the inner surface side can be displayed brightly by turning on the front light unit.

  In one aspect of the electronic apparatus, the control unit can turn on the front light unit located on the inner surface side within a predetermined time after the display unit is closed. In the folded state, in principle, only reflective display using natural light is performed to reduce the number of electrodes consumed. However, for example, immediately after the folding operation, the front light unit can be turned on for a limited time to perform bright display.

  In one aspect of the electronic device, the display image data is supplied to the electro-optical panel as it is in one of the opened state and the closed state, and the display image data is inverted in the other state. And a data processing unit that supplies the electro-optical panel. Accordingly, the display image can be viewed in the correct direction when viewed from either the inner surface side or the outer surface side of the display unit.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, an embodiment of a liquid crystal display device will be described as an example of an electro-optical device.

[First Embodiment]
First, a first embodiment of a liquid crystal display device to which the present invention is applied will be described. FIG. 1 is an exploded perspective view showing a schematic configuration of the liquid crystal display device 1 according to the present embodiment. As shown in the figure, the liquid crystal display device 1 is configured by providing a pair of front light units 30 a and 30 b above and below a single liquid crystal display panel 10. Although FIG. 1 shows a disassembled state, the front light units 30a and 30b are actually attached to and integrated with the liquid crystal display panel 10.

  FIG. 2 is a cross-sectional view of the liquid crystal display device 1 taken along the line X-X ′ of FIG. 1. As shown in the figure, the liquid crystal display device 1 includes a liquid crystal display panel 10 and a pair of front light units 30a and 30b attached to the top and bottom thereof.

  The liquid crystal display panel 10 is formed by bonding a pair of transparent substrates 11 and 12 such as a glass substrate through a sealing material 16 and enclosing a liquid crystal 19 therein. The liquid crystal display panel 10 is a so-called transflective type, and a reflective film 14 for reflecting external light such as sunlight and indoor illumination light is provided on a lower substrate 12. 14 is provided with a plurality of openings 15 for allowing transmitted light to pass therethrough. Further, RGB color filters 12 are provided on the reflective film 14 to enable color display. Further, polarizing plates 17 and 18 are attached to the outer surfaces of the transparent substrates 11 and 12, respectively. The upper and lower transparent substrates 11 and 12 are formed with electrodes according to the driving method of the liquid crystal display panel 12, alignment films for controlling the alignment of liquid crystal molecules, and the like. Omitted.

  The front light units 30 a and 30 b are flat transparent light source units, and each supply illumination light to the liquid crystal display panel 10. That is, the front light unit 30a on the upper side in the figure emits illumination light downward, and the front light unit 30b on the lower side in the figure emits illumination light upward.

  Next, a display method by the liquid crystal display device 1 will be described.

  In FIG. 2, an observer 40 shown in the upper part of the figure can see a display image by transmissive display and reflective display. When the front light unit 30a is turned off and the front light unit 30b is turned on, the illumination light emitted from the front light unit 30b passes through the opening 15 of the liquid crystal display panel 10 as shown in the path L1, and the color It passes through the filter 13, the liquid crystal layer 19, etc., and reaches the observer 40. Thereby, the observer 40 can see a bright transmissive display by the illumination light of the front light unit 30b.

  When the front light unit 30a is turned on and the front light unit 30b is turned off, there is no transmitted light as shown in the path L1. However, as indicated by the path L2, the illumination light emitted from the front light unit 30a passes through the liquid crystal layer 19 and is reflected by the reflective film 14, and passes through the liquid crystal layer 19 again to reach the viewer 40. Therefore, the observer 40 can see a bright reflective display by the illumination light of the front light unit 30a.

  Even when both the front light units 30a and 30b are turned off, if there is sunlight, room illumination light, or other external light on the viewer 40 side, the external light enters the liquid crystal panel 10 along the path L3, and Since the light is reflected by the reflective film 14 and reaches the observer 40, the observer 40 can see a normal reflection display by external light.

  On the other hand, an observer 41 shown in the lower part of the figure can see the transmissive display by the front light unit 30a. That is, when the front light unit 30a is turned on, illumination light from the front light unit 30a passes through the liquid crystal display panel 10 through the opening portion 15 of the reflective film along the path L4 and reaches the observer 41. In this way, the observer 41 can see a bright transmissive display. However, when the front light unit 30a is turned off, basically, there is no illumination light that passes through the liquid crystal layer 19 of the liquid crystal display panel 10 and reaches the viewer 41, so that the viewer 41 cannot see the liquid crystal display.

  Next, an example of an electronic apparatus to which the liquid crystal display device 1 of the first embodiment is applied will be described. FIG. 3 shows an appearance of a double-sided display type mobile phone 60 to which the liquid crystal display device 1 of the present embodiment is applied. 3A shows a state in which the mobile phone 60 is folded, and FIG. 3B shows an open state (normal use state). The cellular phone 60 includes a main body 61 provided with a plurality of operation buttons 63 and a display unit 62 provided to the main body 61 so as to be opened and closed by a hinge mechanism 64 or the like.

  The liquid crystal display device 1 described above is accommodated in the display unit 62. The front light unit 30a of the liquid crystal display device 1 is disposed on the outer surface side of the display unit 62 as shown in FIG. 3A, and the front light unit 30b is disposed on the inner surface side of the display unit 62 as shown in FIG. Be placed. As shown in FIG. 3A, in the folded state, that is, in the state where the display unit 62 is closed, only the front light unit 30a side is exposed. On the other hand, as shown in FIG. 3B, in the normal use state in which the display unit 62 is opened, both the front light units 30a and 30b are exposed. In this state, the user usually has the front light unit on the inner surface side. The display image is viewed from the 30b side.

  Next, a lighting control example of the two front light units 30a and 30b in the mobile phone 60 shown in FIG. 3 will be described. FIG. 4 is a diagram illustrating an example of lighting control of the front light units 30a and 30b. When the display unit 62 is closed as shown in FIG. 3A, both the front light units 30a and 30b are basically turned off. Therefore, as described with reference to FIG. 2, the observer 40 can view the display image of the liquid crystal display device 1 by reflection display using external light.

  However, for example, in a predetermined state such as within a predetermined time after the display unit 62 is closed, bright display can be performed by lighting the front light unit 30a or 30b. That is, as described above, when the front light unit 30a is turned on, bright transmissive display can be performed, and when the front light unit 30b is turned on, bright reflective display can be performed. The reason for turning off both of the front light units 30a and 30b in principle with the display unit 62 closed is generally that the mobile phone is not in use. This is because it is preferable to prevent power consumption due to lighting. Therefore, it is only necessary to light up one of the front light units 30a or 30b within a predetermined time after the display unit 62 is closed or only when the user performs a specific button operation or the like to perform a bright display.

  On the other hand, as shown in FIG. 3B, in the normal use state in which the display unit 62 is opened, the front light unit 30a is turned on to perform bright transparent display. As a result, the user can perform necessary operations while viewing a bright display image in the normal use state.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 5 shows an appearance of the liquid crystal display device 2 according to the second embodiment, and FIG. 6 shows a cross-sectional view taken along the YY ′ cross section. The liquid crystal display device 2 according to the second embodiment is different from the first embodiment in that one front light unit 31a is smaller than the other front light unit 31b, but other points are basically the first embodiment. It is the same as the form. That is, the liquid crystal display device 2 is configured by sandwiching the liquid crystal display panel 10 between a small front light unit 31a and a normal size front light unit 31b. The size of the small front light unit 31a and the position on the outer surface of the liquid crystal display device 10 can be arbitrarily determined according to the electronic device on which the liquid crystal display device 10 is mounted.

  The display principle of the liquid crystal display device 2 is basically the same as that of the first embodiment. That is, in FIG. 6, the observer 40 displays a bright transmissive display when the front light unit 31b is turned on (see path L1), a bright reflected display when the front light unit 31a is turned on (see path L2), and the front The display image can be viewed by any of the normal transmissive displays (see path L3) when both the light units 31a and 31b are turned off. However, since the front light unit 31a has a smaller illumination area than the entire display area of the liquid crystal display panel 10, basically the front light unit 31a can perform bright reflective display when the front light unit 31a is turned on. Limited to the illumination area 31a.

  On the other hand, by turning on the front light unit 31a, the observer 41 can see a bright transmissive display. Also in this case, since the front light unit 31a has a smaller illumination area than the entire display area of the liquid crystal display panel 10, basically the front light unit 31a can perform bright transmissive display when the front light unit 31a is turned on. It is limited to the illumination area of the light unit 31a.

  FIG. 7 shows an example of a double-sided display type mobile phone to which the liquid crystal display device 2 of the second embodiment is applied. FIG. 7A shows a folded state, and FIG. 7B shows a normal use state. The structure of the casing of the mobile phone 70 is basically the same as that of the mobile phone 60 in the first embodiment, and a display unit 72 is attached to the main body 71. The liquid crystal display device 2 is accommodated in the display unit 72 such that the small front light unit 31 a is located on the outer surface side of the display unit 72 and the normal size front light unit 31 b is located on the inner surface side of the display unit 72. .

  However, in this case, when the liquid crystal display device 2 shown in FIG. 5 is used, in the normal use state shown in FIG. 7B, since the illumination area by the front light unit 31a is small, the brightness of the peripheral area of the display image is insufficient. Will be. Therefore, as shown in FIG. 8, an auxiliary front light unit 32 can be provided so as to surround the small front light unit 31a. Thus, in the normal display state shown in FIG. 7B, the front light units 31a and 32 can be turned on to perform bright transmissive display in the entire display area.

  On the other hand, when a bright display is desired in the folded state shown in FIG. 7A, only the small front light unit 31a can be turned on to perform a bright reflective display. In this case, it is not necessary to turn on the auxiliary front light unit 32. Therefore, in order to perform bright display with the display unit 72 closed, a display method that consumes less power and is less wasteful than performing bright transmissive display by turning on the normal-sized front light unit 31b. That is, if the auxiliary front light unit 32 as shown in FIG. 8 is used, the front light units 31a and 32 are controlled to be turned on independently, so that a bright display can be performed with low power consumption in any state. It becomes.

[Display image control]
Next, display image control in the liquid crystal display devices 1, 2, and 2a will be described. FIG. 9 is a schematic block diagram illustrating a circuit configuration of an electronic apparatus to which the liquid crystal display device is applied. The electronic apparatus shown here includes the liquid crystal display panel 10 that constitutes the liquid crystal display device 1, 2, or 2a, and a control unit 410 that controls the liquid crystal display panel 10. Here, the liquid crystal display panel 10 is conceptually divided into a panel structure 400A and a drive circuit 400B formed of a semiconductor IC or the like. The control unit 410 includes a display information output source 411, a display information processing circuit 412, a power supply circuit 413, and a timing generator 414.

  The display information output source 411 includes a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), a storage unit such as a magnetic recording disk or an optical recording disk, and a tuning circuit that tunes and outputs a digital image signal. The display image data is supplied to the display information processing circuit 412 in the form of an image signal of a predetermined format based on various clock signals generated by the timing generator 414.

  The display information processing circuit 412 includes various known circuits such as a serial-parallel conversion circuit, an amplification / inversion circuit, a rotation circuit, a gamma correction circuit, and a clamp circuit, and executes processing of input display information to display the display image. Data DAT is supplied to drive circuit 400B together with clock signal CLK. The driving circuit 400B includes a scanning line driving circuit, a data line driving circuit, and an inspection circuit. The power supply circuit 413 supplies a predetermined voltage to each of the above-described components.

  In the above liquid crystal display device, the display image can be viewed from both sides as described above. Therefore, for example, when the display image data DAT is supplied to the drive circuit 400B so that the display image can be normally viewed from the front light unit 30b side in the normal display state shown in FIG. 3B, the folded state shown in FIG. Thus, when the same display image data DAT is viewed from the front light unit 30a side, the display image is inverted. Therefore, a state detection unit 510 that detects the state of the display unit 62 is provided, and the detection result is supplied to the display information processing circuit 412 as a control signal S. In response to the control signal S, the display information processing circuit 412 supplies the display image data DAT as it is or after being inverted to the drive circuit 400B. The state detection unit 510 can be configured by, for example, an electrical detection switch that contacts when the display unit 62 is in a closed state and is non-contact when the display unit 62 is in an open state.

  Specifically, when the state detection unit 510 detects that the display unit 62 is in the normal use state shown in FIG. 3B, the display information processing circuit displays the display image (in the center) shown in FIG. A display image including a triangle) is supplied to the drive circuit 400B as it is. On the other hand, when the state detection unit 51 detects that the display unit 62 is in the folded state shown in FIG. 3A, the display information processing circuit 412 displays the display image data as a center line as shown in FIG. Inverted with C as an axis, supplied to the drive circuit 400B. As a result, the user can view a display image in the correct orientation in any state.

1 is an exploded perspective view of a liquid crystal display device according to a first embodiment of the present invention. 1 is a cross-sectional view of a liquid crystal display device according to a first embodiment. 2 shows an example of an electronic apparatus to which the liquid crystal display device according to the first embodiment is applied. An example of lighting control of the front light unit of the electronic device shown in FIG. 3 is shown. It is a disassembled perspective view of the liquid crystal display device which concerns on 2nd Embodiment of this invention. It is sectional drawing of the liquid crystal display device which concerns on 2nd Embodiment. The example of the electronic device to which the liquid crystal display device which concerns on 2nd Embodiment is applied is shown. It is sectional drawing of the modification of the liquid crystal display device which concerns on 2nd Embodiment. It is a circuit block diagram of the electronic device to which this invention is applied. 4 shows inversion processing of display image data in an electronic apparatus to which the present invention is applied.

Explanation of symbols

1, 2, 2a Liquid crystal display device, 10 Liquid crystal display panel, 11, 12 Transparent substrate,
14 reflective film, 15 aperture, 17, 18 polarizing plate, 19 liquid crystal,
30, 31, 32 Front light unit, 60, 70 Mobile phone,
61, 71 body, 62, 72 display unit

Claims (8)

An electro-optic panel comprising an electro-optic material sandwiched between a pair of substrates;
A pair of polarizing plates affixed to the outer surface of each substrate;
An electro-optical device comprising: a pair of front light units attached to outer surfaces of the pair of polarizing plates.   The electro-optical device according to claim 1, wherein the electro-optical panel is provided with a reflective film having a plurality of openings on one of the substrates.   The front light unit on the substrate side opposite to the substrate on which the reflective film is provided has a smaller illumination area than the front light unit on the substrate side on which the reflective film is provided. Electro-optic device.   The front light unit on the substrate side opposite to the substrate on which the reflective film is provided is configured by a plurality of front light units having an illumination area smaller than that of the front light unit on the substrate side on which the reflective film is provided. The electro-optical device according to claim 2. A main body, a display unit attached to the main body so as to be openable and closable, and an electro-optical device provided in the display unit,
The electro-optical device includes:
An electro-optic panel having an electro-optic material sandwiched between a pair of substrates;
A pair of polarizing plates affixed to the outer surface of each substrate;
A pair of front light units attached to the outer surfaces of the pair of polarizing plates;
With
One of the front light units is located on the outer surface side exposed to the outside with the display unit closed, and the other of the front light units is located on the inner surface side exposed with the display unit opened. An electronic apparatus, wherein the electro-optical device is accommodated in the display unit.   The display unit further includes a control unit that turns off both the pair of front light units when the display unit is closed, and turns on the front light unit located on the outer surface side when the display unit is opened. The electronic device according to claim 5.   The electronic device according to claim 6, wherein the control unit lights one of the front light units located on the inner surface side or the outer surface side within a predetermined time after the display unit is closed. . Data in which the display image data is supplied to the electro-optical panel as it is in one of the open state and the closed state, and the display image data is inverted and supplied to the electro-optical panel in the other state. The electronic device according to claim 6, further comprising a processing unit.

Images