JP2004198886A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device excellent in convenience, commercially produced, capable of being constituted more thinly and lightly and inexpensively manufactured. <P>SOLUTION: A liquid crystal panel 23 is formed as a semitransmission type or a transmission type and a front light is disposed on at least one surface of the semitransmission type liquid crystal display panel 23 and front lights 27 and 27' are disposed on both surfaces of the transmission type liquid crystal panel 23. Thereby, a conventional defect is solved, that the whole thickness and weight of liquid crystal display of a double sided image display type such as a terminal of a cellular phone are increased and the display is inconvenient as a product since a pair of liquid crystal displays are combined back to back. The whole thickness of the liquid crystal display device can be made thin and the weight thereof can be made light, used material can be reduced to attain cost reduction and the liquid crystal display device excellent in convenience can be obtained. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal display device having a front light disposed on at least one side, and more particularly to a liquid crystal display device capable of observing a screen from any side of the liquid crystal display device.
[0002]
[Prior art]
A liquid crystal display device can be configured to be lightweight and thin, and has characteristics such as low power consumption, so that it is used as a display monitor of an information terminal, a clock, a television receiver, and the like. In particular, in the case of a foldable mobile phone terminal, clock information is displayed on an external liquid crystal display device that is disposed on both sides of the open / close lid and is exposed to the outside with the lid closed, for example, and the lid is opened. The liquid crystal display device on the inner surface, which is exposed in a folded state, is configured to display various information such as incoming mail information, outgoing mail information, and telephone number.
[0003]
As described above, the liquid crystal display device that displays different necessary information according to the opening and closing of the lid is extremely convenient for the user, but the liquid crystal display device of the double-sided display has a pair of independent parts on the lid portion. It adopts a configuration incorporating a liquid crystal display device.
[0004]
Therefore, the thickness and weight of the entire pair of liquid crystal display devices to be incorporated are simply required to be twice that of a single liquid crystal display device, which not only results in increasing the thickness and weight of the device. However, an increase in cost could not be avoided.
[0005]
[Problems to be solved by the invention]
As described above, in order to configure the screen of the liquid crystal display device so that it can be viewed from both sides, a pair of independent liquid crystal display devices are combined back to back, and the liquid crystal display device is configured as if it were one liquid crystal display device. Therefore, the thickness of the liquid crystal display device built in the device becomes thicker and heavier, so that there is still room for improvement, especially when adopted in a portable device. Therefore, development of more convenient equipment is desired.
[0006]
The present invention has been made in view of such a problem, and a single liquid crystal panel is configured as a transflective type or a transmissive type, and a front light is arranged on at least one side of the liquid crystal panel, so that a liquid crystal display device is provided. It is an object of the present invention to provide a liquid crystal display device capable of observing a display image from any surface side of the liquid crystal display device and capable of being formed thin and lightweight.
[0007]
[Means for Solving the Problems]
The present invention provides an array substrate provided with one electrode, a counter substrate provided with the other electrode on a surface facing the array substrate, a plurality of spacers defining a gap between the counter substrate and the array substrate, A liquid crystal member sandwiched between the opposing array substrate and the opposing substrate, a transflective reflective layer disposed on one of the array substrate and the opposing substrate, and a substrate on the opposite side of the substrate provided with the reflective layer. And a front light disposed on the outer surface, so that a screen can be selectively displayed from either side of the pair of substrates.
[0008]
With this configuration, the front light can function as a front light or a backlight, images can be observed from both sides, and the overall thickness of the device can be reduced. Since the weight can be reduced, it is possible to obtain a liquid crystal display device which is particularly suitable for use in a portable product or a product which is used by overlapping a plurality of products.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0010]
As shown in FIG. 1, the color liquid crystal display device according to the present invention forms a film on a main surface of an array substrate 11 made of a transparent glass material having a thickness of about 0.5 to 1 mm. The electrode wiring and the TFT 12 are arranged by making full use of microtechnology. The TFT 12 and the electrode wiring are configured as follows, for example.
[0011]
That is, amorphous silicon is formed on the main surface of the array substrate 11 by plasma CVD (Chemical Vapor Deposition), and then the amorphous silicon is polycrystallized by excimer laser annealing to form polysilicon. This polysilicon is patterned to form a semiconductor layer of the TFT 12.
[0012]
Next, a silicon oxide film is formed by plasma CVD using tetraethoxysilane as a material to form a gate insulating film.
[0013]
A gate electrode and a scanning line are formed by forming a film of molybdenum / tungsten on the gate insulating film by a sputtering method and patterning the film.
[0014]
Then, a silicon oxide film is formed by a plasma CVD method so as to cover the gate electrode, thereby forming an interlayer insulating film.
[0015]
Next, a contact hole is formed in a part of the interlayer insulating film and the gate insulating film by using a photolithography method.
[0016]
Further, a source electrode, a drain electrode and a signal line of the TFT 12 are formed by forming a metal film containing aluminum as a main component on the interlayer insulating film by a sputtering method and patterning the metal film. At this time, the drain electrode and the signal line are integrated, and the drain electrode is connected to the drain region of the semiconductor layer via the contact hole. The source electrode is connected to the source region of the semiconductor layer via another contact hole.
[0017]
The color filter 14 is formed on the array substrate 11 including the TFT 12 formed as described above. The color filter 14 is color-coded into red (R), blue (B), and green (G), and each color is formed in a stripe shape.
[0018]
Further, a transparent pixel electrode 13 is formed on the color filter 14 by forming a film of ITO (Indium Tin Oxide) using a sputtering method and patterning the film. The pixel electrode 13 is connected to a source electrode of the TFT 12 via a contact hole provided in the color filter 14.
[0019]
Further, the frame layer 16 and the spacer 15 are formed by depositing and patterning a black resin. The spacers 15 are provided at a ratio of one to one pixel or a plurality of pixels, and are preferably arranged in a light shielding portion such as on the TFT 12 or on various wirings from the viewpoint of an aperture ratio.
[0020]
Then, a film made of polyimide is applied to the entire surface of the array substrate 11, and the film is subjected to an alignment process to form an alignment film 17.
[0021]
A drive circuit is built in the peripheral portion of the array substrate 11 at the same time when the TFT 12 is manufactured.
[0022]
On the other hand, a counter substrate 18 is arranged to face the array substrate 11. The opposing substrate 18 is also made of a transparent glass material having a thickness of about 0.5 to 1 mm, and has a transparent opposing surface which constitutes the other electrode made of ITO or the like on the opposing surface opposing the array substrate 11. An electrode 19 and an alignment film 20 made of polyimide or the like are sequentially laminated on the counter electrode 19.
[0023]
The opposing substrate 18 and the array substrate 11 are fixed while maintaining a predetermined gap by the spacer 15 and heat-adhering the periphery except for the injection port by a sealing material 21 made of, for example, a thermosetting epoxy adhesive. In addition, an electrode transfer material for applying a voltage from the array substrate 11 to the counter substrate 18 is formed on an electrode transfer electrode (not shown) around the seal material 21. A liquid crystal member 22 made of, for example, a fluorine-based liquid crystal compound is injected into the gap, and then the injection port is sealed with an ultraviolet curable resin to form a liquid crystal panel 23. Further, polarizing plates 24 and 25 are adhered and fixed to the outer surfaces of the array substrate 11 and the counter substrate 18 of the liquid crystal panel 23, respectively. A layer 26 is arranged, and a front light 27 is arranged on the outer surface of the polarizing plate 25 of the counter substrate 18. The front light 27 includes a light source unit 28 and a light guide plate 29 made of a transparent material having a sawtooth-shaped step and connected to the light source unit 28 and disposed so as to cover the surface of the liquid crystal panel 23. An apparatus 30 is configured.
[0024]
When the color liquid crystal display device is configured in this manner, the liquid crystal panel 23 can be driven by, for example, supplying a predetermined driving voltage to the TFT 12 and the counter electrode 19 of the liquid crystal panel 23 from a driving circuit (not shown). It becomes. Then, as shown in FIG. 2, external light indicated by an arrow A incident from the counter substrate 18 side of the liquid crystal panel 23 is reflected by the semi-transmissive reflective layer 26 in accordance with the optical shutter operation of the liquid crystal member 22 and used. Is recognized by a person as a color image.
[0025]
When the front light 27 is turned on, the light emitted from the light source unit 28 is reflected in the light guide plate 29 and enters the liquid crystal panel 23 as shown by the arrow B, and the light shutter operation of the liquid crystal member 22 is performed. Is reflected by the semi-transmissive reflective layer 26 and reaches the user side. Therefore, an image is displayed by both lights A and B in combination with the external light A, so that a bright screen can be displayed. Of course, if sufficient brightness can be obtained with only the external light A, it is not necessary to turn on the front light 27.
[0026]
On the other hand, when the liquid crystal display device 30 is viewed from the opposite surface side where the front light 27 is located, the front light 27 is turned on, so that the front light 27 functions as a backlight, and the light of the front light 27 As shown by an arrow C in the figure, an image is displayed through the liquid crystal panel 23 and the transflective reflective layer 26, and the liquid crystal display device 30 can function as a double-sided display type.
[0027]
As described above, a color liquid crystal display device 30 capable of displaying images on both sides by arranging the front light 27 on one surface of the liquid crystal panel 23 having the transflective reflective layer 26 is, for example, shown in FIG. Thus, it can be used as a display panel of a mobile phone terminal. The telephone terminal includes a terminal body 32 provided with an operation input button 31 and the like, and a lid body rotatably held at one end so as to be openable and closable on the terminal body 32 so as to selectively cover the operation input button 31. It is composed of a part 33. The color liquid crystal display device 30 is attached to the lid 33 so that the display portion is exposed on both the front and back sides, for example, so that the front light 27 is located on the outer surface side of the lid 33. A switch 34 for switching and selecting the driving start position of the liquid crystal panel 23 is arranged in the terminal main body 32. The switch 34 drives the surface on the front light 27 side when the lid 33 is closed, and switches so that a normal image is displayed on the surface on the opposite side to the front light 27 when opened. The switching configuration is as follows.
[0028]
That is, as shown in FIG. 3B, one side of the liquid crystal panel 23, for example, on the left side in the figure, has a pair of input terminals 35, 36 at the upper and lower ends. The other input terminal 36 is connected to a second fixed terminal 38, and the first and second fixed terminals 37 and 38 are connected to a video signal and drive voltage supply circuit 39. The switching terminal 40 is switched and connected.
[0029]
Accordingly, when the lid 33 is opened, the switch 34 is switched to the first fixed terminal 37 side, and the video signal and the drive voltage from the video signal and drive voltage supply circuit 39 are switched from the switch terminal 40 to the first The liquid crystal panel 23 is supplied to the input terminal 35 through one fixed terminal 37 and drives the liquid crystal panel 23 to display a predetermined image.
[0030]
On the other hand, when the lid 33 is closed, the switch 34 is switched to the second fixed terminal 38 side, and the video signal and the drive voltage are supplied to the input terminal 36 through the switching terminal 40 and the second fixed terminal 38. Is done. The drive start position for scanning the liquid crystal panel 23 when the lid 33 is closed, since the display surface of the liquid crystal panel 23 is inverted by 180 ° compared to when the lid 33 is open. Also needs to be inverted, so that the switch 34 is required. By switching the switch 34 in this manner, it is possible to display a normal image when viewed from any side of the liquid crystal panel 23.
[0031]
In order to selectively turn on the front light 27, for example, a second switch 41 is disposed on a side surface of the terminal main body 32, and the switch 41 is interposed between the front light power supply circuit 42 and the front light 27. Thus, the front light 27 can be turned on by selectively operating the switch 41. When the front light 27 is always turned on, the switch 41 can be omitted, and the liquid crystal display device 30 is driven with the lid 33 opened to mainly display main information. In the case where the front light 27 is turned on only when the operation is performed and the front light 27 functions as a backlight, the switches 34 and 41 are configured to operate in conjunction with each other, It is also possible to configure with the switch of.
[0032]
As described above, in a case where the color liquid crystal display device 30 is used by opening and closing it back and forth according to opening and closing of the lid as in a mobile phone terminal, it is only necessary to change the driving start point of the liquid crystal panel 23. Since it is possible to respond, it is possible to simplify the manufacturing process of the product.
[0033]
Further, as shown in FIG. 4, the front lights 27 can be arranged on both sides of the liquid crystal panel 23, respectively. By arranging the front lights 27, 27 'on both sides of the liquid crystal panel 23 in this manner, when the liquid crystal display device 30 is observed from one side, for example, when observed from the left side in the drawing, the front lights 27, 27' are When both are turned off, only the external light A is reflected by the liquid crystal panel 23 as shown by the arrow A to function as a reflective color liquid crystal display device that displays an image. When only the front light 27 is turned on, an image can be displayed by both the reflected light B from the front light 27 and the external light A as indicated by an arrow B in the drawing. Further, even when the external light A cannot be used in a dark place or at night, an image can be displayed only with the reflected light B from the front light 27.
[0034]
When the front light 27 ′ is turned on, the front light 27 ′ functions as a backlight as shown by an arrow C ′ in the figure, and the light C ′ of the front light 27 ′ And functions as a transmissive color liquid crystal display device 30. Similarly, even when observed from the right side in the figure on the opposite side, each external light A ′, the reflected light B ′ of the front light 27 ′, and the transmitted light C of the front light 27 can be used, respectively. Can also function as a reflective or transmissive color liquid crystal display device 30.
[0035]
Also, instead of providing the transflective reflective layer 26, instead of the reflective layer 26, front lights 27 and 27 'are provided on both sides of the liquid crystal panel 23 as shown in FIG. 23 can be configured as a transmission type. In this case, the front lights 27 and 27 'function as backlights, respectively, so that the light from the front lights 27 and 27' indicated by arrows C and C 'in the figure is transmitted through the liquid crystal panel 23. The transmissive color liquid crystal display device 30 can be configured.
[0036]
In the color liquid crystal display device 30 having any of the above-described configurations, the case where the color liquid crystal display device 30 is formed in a non-flexible solid state that is used by opening and closing in the front-rear direction has been described. When the color liquid crystal display device 30 is used, it is assumed that the color liquid crystal display device 30 itself is curved due to its usage. In such a case, the array substrate 11, the opposing substrate 18, and the light guide plates 29, 29 'of the front lights 27, 27' themselves are formed to have flexibility, and the color liquid crystal display device 30 is curved. In some cases, it is more convenient to provide flexibility so as to allow for convenience.
[0037]
When the color liquid crystal display device 30 is made flexible in this way, the outer surfaces of the substrates 11, 18 are mechanically polished or chemically polished at the stage of forming the sealing material 21 before injecting the liquid crystal member 22. The respective substrates 11 and 18 are polished to a thickness of about 0.1 mm by polishing, or a combination of both of these polishing, so as to have flexibility. Liquid crystal is reinforced by attaching a flexible reinforcing plate (not shown) made of a transparent resin plate or the like for prevention of breakage to the polished outer surfaces of the substrates 11 and 18. The entire panel 23 can be made flexible. The reinforcing plate may be replaced by the polarizing plates 24 and 25.
[0038]
Also, the light guide plates 29, 29 'of the front lights 27, 27' are also flexible so as to follow the bending direction of the liquid crystal panel 23 so that the entire color liquid crystal display device 30 is bent. It is possible to do.
[0039]
By making the color liquid crystal display device 30 itself flexible in this way, it is suitable for use in an electronic book, an electronic organizer, or the like, and can display two pages of the product. In this case, when the present invention is applied to a product that opens and closes left and right, it is difficult to form the front and back of the liquid crystal panel 23 completely symmetrically. The input terminals 35 and 36 are arranged in the directions, respectively, and a video drive signal adjustment circuit (FIG. 1) for matching the image display state on the other side between one of the input terminals 35 and 36 and the fixed terminals 37 and 38 of the switch 34. (Not shown). Of course, this is not necessary in the case of a monochrome liquid crystal display device configured to display only a monochrome image display.
[0040]
Note that the present invention is not limited to those described in the embodiments, and various applications and modifications are possible. For example, when patterning the material of the color filter 14, a colored layer constituting the color filter 14 may be used. If the laminated spacers 15 are formed by sequentially laminating the materials and simultaneously forming the colored layers, the manufacturing process of the spacers 15 can be simplified. Further, the spacer 15 can be constituted by a spherical spacer 15.
[0041]
Further, the color filter 14 can be configured to be provided on the counter substrate 18, or the frame layer 16 can be formed on the counter substrate 18 side. Further, the spacer 15 is not limited to one having one end fixed to the array substrate 11 side, but can be fixed to the counter substrate 18 side, and furthermore, can be arranged so as to protrude from both substrates 11 and 18 respectively. . Needless to say, the present invention can be applied not only to a color liquid crystal display device but also to a black and white liquid crystal display device.
[0042]
【The invention's effect】
As described above, according to the present invention, by arranging front lights on at least one side surface of the transflective liquid crystal panel or on both sides of the transmissive liquid crystal panel, a liquid crystal display device capable of double-sided display is configured. Therefore, the overall thickness of the liquid crystal display device can be reduced and the weight can be reduced. Further, since the material used can be reduced, the cost can be reduced and the convenience is improved. A liquid crystal display device can be obtained.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a liquid crystal display device according to the present invention.
FIG. 2 is an explanatory diagram for explaining a screen display state of the liquid crystal display device.
FIG. 3 is an explanatory diagram showing a state in which the liquid crystal display device is similarly incorporated in a mobile phone terminal.
FIG. 4 is an explanatory diagram for explaining a screen display state of another configuration of the liquid crystal display device.
FIG. 5 is an explanatory diagram for explaining a screen display state of another configuration of the liquid crystal display device.
[Explanation of symbols]
11: Array substrate 13: Pixel electrode (one electrode)
15: Spacer 18: Counter substrate 19: Counter electrode (the other electrode)
22: Liquid crystal member 26: Transflective reflective layers 27, 27 ': Front lights 34, 41: Switch

Claims (8)

An array substrate having one electrode,
An opposing substrate having the other electrode on the opposing surface opposing the array substrate;
A plurality of spacers defining a gap between the counter substrate and the array substrate;
A liquid crystal member sandwiched between the opposed array substrate and the opposed substrate,
A transflective reflective layer disposed on either side of the substrate,
A front light disposed on the outer surface of the substrate opposite to the substrate provided with the reflective layer,
A liquid crystal display device wherein a screen can be selectively displayed from either side of the pair of substrates. 2. The liquid crystal display device according to claim 1, wherein a front light is arranged on an outer surface of the substrate on which the transflective reflection layer is provided. 2. The liquid crystal display device according to claim 1, wherein a front light is arranged in place of the transflective reflection layer to constitute a transmissive type. 2. The liquid crystal display device according to claim 1, wherein the two substrates and the front light have flexibility. 2. The liquid crystal display device according to claim 1, further comprising a switch for controlling an input position to at least one side of the electrode corresponding to a viewing direction of the two substrates. 2. The liquid crystal display device according to claim 1, further comprising a switch for controlling lighting of the front light. The liquid crystal display device according to claim 1, wherein the front light is turned on to function as a light on the front light side. The liquid crystal display device according to claim 1, wherein the front light is turned on to function as a backlight.

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