JP2003215548A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission type liquid crystal display device of a structure simpler than a conventional one. <P>SOLUTION: Signal electrodes 4 extending in parallel to each other in a 1st direction are formed on a liquid crystal layer 5 side of a 1st substrate 1, and moreover, an optical conductive layer 7 brought into conduction by being irradiated with ultraviolet thereon is formed on the liquid crystal layer 5 side of a 2nd substrate 8. Further, the optical conductive layer 7 is irradiated with ultraviolet from a light emitting part 15, and pseudo electrodes extending in parallel to each other in a 2nd direction orthogonal to the 1st direction are formed. Then, a driving voltage is applied to the liquid crystal layer 5 held between the pseudo electrodes and the signal electrodes 4. Therefore, since the optical conductive layer 7 is directly utilized as the electrodes for applying the driving voltage to the liquid crystal layer 5, the structure of the electrodes is simplified, the transmission type liquid crystal display device 13 of a structure simpler than a conventional one can be realized, and it becomes possible to decrease material costs and the number of manufacturing processes, and to prevent yield from decreasing. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a transmissive liquid crystal display device using an optical address system.

[0002]

2. Description of the Related Art Conventionally, liquid crystal display devices can be roughly classified into an electric addressing system, a thermal addressing system and an optical addressing system according to their driving systems.

Of these, the most widely used at present is the electrical addressing method. The electrical address system has a high resolution (VGA or XGA level resolution)
Since it can display moving images, it is used in direct-view liquid crystal display devices such as personal computer monitors and liquid crystal TVs. A direct-view liquid crystal display device is a thin film transistor (TFT).
Stor) is used as a switching element, and a TFT liquid crystal display device can be mentioned.

The optical address system is adopted in a projection type liquid crystal display device. The projection type liquid crystal display device includes a photoconductive layer, and a drive voltage is applied to the liquid crystal layer by irradiating the photoconductive layer with light to make it conductive. Therefore, the projection type liquid crystal display device has a simple structure and is easy to manufacture as compared with a direct view type liquid crystal display device using a semiconductor switching element such as a TFT, and thus is easy to increase in size,
And it becomes cheaper.

However, unlike a transmissive display device which can be widely used for a monitor for a personal computer, a liquid crystal TV, etc., the projection type liquid crystal display device is limited in application to a projector as a product.

Therefore, it has been attempted to manufacture a transmissive liquid crystal display device of an optical addressing system using a photoconductive layer.

According to the attempt, since a visible light source (backlight) is indispensable for a transmissive liquid crystal display device, an address light source for irradiating light other than visible light (for example, ultraviolet light) and an incident light. It is necessary to provide a photoconductive layer that causes a change in electric resistance value.

In Japanese Laid-Open Patent Publication No. 11-282004 (publication date: October 15, 1999), FIG.
Discloses a transmissive liquid crystal display device.

The transmissive liquid crystal display device has a front substrate 80.
And a rear substrate 86, and a liquid crystal layer 82 is sandwiched between the pair of substrates. Also,
A common electrode 81 is solidly formed on the liquid crystal layer 82 side of the front substrate 80, and a pixel electrode 83, a photoconductive layer 84, and a signal electrode 85 are formed on the liquid crystal layer 82 side of the rear substrate 86. ing.

An address light source (not shown) is provided on the side of the rear substrate 86 opposite to the liquid crystal layer 82.

Then, the photoconductive layer 84 is irradiated with the address light from the address light source to bring the photoconductive layer 84 into conduction, thereby switching ON / OFF by switching between the signal electrode 85 and the pixel electrode 83. Then, the liquid crystal is driven by the voltage difference between the common electrode 81 facing the pixel electrode 83 with the liquid crystal layer 82 interposed therebetween.

[0012] Further, JP-A-9-185332 (publication date: July 15, 1997) and JP-A-10-82994 (publication date: 1998 (199)
8) March 31) discloses an example in which an organic EL is used as an addressing light source and ZnO, TiO ₂ or the like is used as a material for a photoconductive layer.

[0013]

However, since the structure of the above-mentioned conventional transmissive liquid crystal display device is complicated, the material cost is high, the number of manufacturing steps is large, and the decrease in yield cannot be prevented. .

The present invention has been made to solve the above problems, and an object thereof is to provide a transmissive liquid crystal display device having a simple structure.

[0015]

In order to solve the above-mentioned problems, a liquid crystal display device of the present invention has a first substrate, a second substrate and a first substrate and a second substrate sandwiched between them. And a signal electrode formed on the liquid crystal layer side of the first substrate and parallel to each other extending in the first direction, and formed on the liquid crystal layer side of the second substrate, and conducting by irradiation with ultraviolet light. A photoconductive layer; and a light emitting section for irradiating the photoconductive layer with ultraviolet light so as to form mutually parallel pseudo electrodes extending in a second direction orthogonal to the first direction. .

According to the above structure, first, the signal electrode is an electrode for applying a signal voltage to each pixel of the display screen, and is an electrode made of a transparent conductive material such as ITO. A plurality of signal electrodes are formed on the first substrate in parallel with each other.

The photoconductive layer is made of a photoconductive material which is almost transparent to visible light, and its electric resistance value is changed by ultraviolet light, that is, it is conducted (energized) by irradiating with ultraviolet light to generate ultraviolet light. It is a layer that does not conduct when light is no longer applied. The photoconductive layer is formed in a solid arrangement on the second substrate, and the signal electrode and the photoconductive layer are provided with the liquid crystal layer interposed therebetween.

Utilizing the characteristics of the photoconductive layer, the region irradiated with ultraviolet light is used as an electrode for driving the liquid crystal. Since the electrode is a pseudo electrode portion while the photoconductive layer is being irradiated with ultraviolet light, it is referred to as a pseudo electrode here.

Therefore, when the photoconductive layer is irradiated with ultraviolet light so as to be orthogonal to the first direction of the signal electrode, the pseudo electrode is also formed so as to be orthogonal to the signal electrode. An intersection is formed at the intersection, and a voltage is applied to the liquid crystal at the intersection.

As described above, since the photoconductive layer can be directly used as the electrode for applying the driving voltage to the liquid crystal, the structure of the electrode can be simplified.

Therefore, it is possible to realize a transmissive liquid crystal display device having a simpler structure than the conventional one, and it is possible to prevent a reduction in material cost, a reduction in the number of manufacturing steps, and a reduction in yield.

Furthermore, the liquid crystal display device of the present invention is characterized in that the light emitting portion sequentially emits light so that the pseudo electrodes are sequentially formed.

With the above structure, the photoconductive layer is successively irradiated with ultraviolet light from the light emitting portion, and pseudo electrodes are sequentially formed on the photoconductive layer. Thereby, the liquid crystal at the intersection of the pseudo electrode and the signal electrode orthogonal to the pseudo electrode can be sequentially driven, and an image can be displayed.

Further, the liquid crystal display device of the present invention is characterized in that a common electrode for supplying a common voltage to the pseudo electrode is formed outside the display region.

With the above structure, since the common electrode is formed outside the display area, there is no great limitation on the material and shape of the common voltage. For example, a metal paste or a conductive polymer material is screen-printed or dispensed. It is an extremely low-cost method because it can be applied only by.

Further, the liquid crystal display device of the present invention is characterized in that the common electrode is formed in the display region.

With the above structure, since the common electrode is further formed in the display area, there is some limitation (for example, the aperture ratio is reduced, and if it is not formed in a uniform shape, the display image becomes uneven). Although generated, the electric resistance value of the photoconductive layer (pseudo electrode) (as one line) at the time of irradiation with ultraviolet light can be lowered, so that the method is suitable for larger size.

Further, the liquid crystal display device of the present invention is characterized in that the common electrode formed in the display region is formed in parallel with the pseudo electrode.

With the above structure, the distance between each part of the pseudo electrode and the common electrode is further shortened, and the electric resistance value of the photoconductive layer (pseudo electrode) is reduced. The applied voltage can be reduced. In other words, it is possible to apply a voltage to a larger pseudo electrode with the same drive voltage. Therefore, the size of the liquid crystal display device can be increased.

Further, the liquid crystal display device of the present invention is characterized in that the common electrode is formed on the photoconductive layer so as to overlap with the pseudo electrode.

With the above structure, further, each part of the pseudo electrode and the common electrode are electrically connected directly, that is, the distance between each part of the pseudo electrode and the common electrode is shortened. The effect of is obtained.

Further, the liquid crystal display device of the present invention is characterized in that a pixel electrode defining a pixel region is formed on the photoconductive layer.

The intersection area between the pseudo electrode formed by irradiating the photoconductive layer with ultraviolet light and the signal electrode orthogonal to each other is a pixel area, and the pseudo electrode and the signal electrode are provided with the liquid crystal layer interposed therebetween. Therefore, they are not in contact with each other, and their pixel regions (pixel shapes) are not defined.

Therefore, an electrode portion is formed on the photoconductive layer in the intersecting region using a transparent conductive material such as ITO. Therefore, the shape of the formed electrode portion becomes the pixel shape (pixel area), that is, by providing the pixel electrode,
A pixel area is defined.

Therefore, with the above structure, the photoconductive layer (as one line) (pseudo electrode) is further irradiated with ultraviolet light.
The electric resistance of the display device can be reduced, and the display device has low power consumption.

Further, the liquid crystal display device of the present invention is characterized in that the pixel electrode has a width in the second direction larger than that of the pseudo electrode.

With the above structure, the voltage can be applied to a region other than the ultraviolet light irradiation region (pseudo electrode) in the photoconductive layer, so that the region that cannot normally be used as a pixel region (for example, on a rib partition wall). Area) can also be used as a pixel area. Therefore, it is possible to display with higher brightness.

Further, the liquid crystal display device of the present invention is characterized in that the light emitting portion is provided for each of the pseudo electrodes at a position facing the pseudo electrode.

With the above structure, further, the ultraviolet light from the light emitting portion becomes a stripe shape, and stripe-like pseudo electrodes extending in the direction orthogonal to the signal electrode are provided in the photoconductive layer at a position facing the light emitting portion. Can be formed.

Further, the liquid crystal display device of the present invention is characterized in that the light emitting portion has a discharge space in which an ionizable gas is sealed, and a discharge electrode is provided in the discharge space. .

With the above structure, when a voltage is further applied to the discharge electrodes arranged in the discharge space to cause discharge, the gas in the discharge space is ionized (plasmaized) to emit ultraviolet light (ultraviolet light). Radiate. The ultraviolet light can be used to form a pseudo electrode in the photoconductive layer.

Further, the liquid crystal display device of the present invention is characterized in that a phosphor is provided on the inner wall of the discharge space.

With the above structure, of the ultraviolet light generated from the ionized gas, the ultraviolet light emitted to the front surface is used for forming the pseudo electrode in the photoconductive layer.
The remaining ultraviolet light enters the phosphor and becomes white light (visible light).

Therefore, since the light emitting section can serve as both the ultraviolet light emitting device and the visible light emitting device (backlight), a thinner and lower cost liquid crystal display device can be realized.

Further, the liquid crystal display device of the present invention is characterized in that a polarizing layer is provided between the photoconductive layer and the liquid crystal layer.

According to the above arrangement, the ultraviolet light from the light emitting portion is further incident on the photoconductive layer before it is incident on the polarizing layer. That is, the ultraviolet light can be incident on the photoconductive layer to form a pseudo electrode on the photoconductive layer before it is incident on the polarizing layer and is almost absorbed.

Therefore, the ultraviolet light can be used efficiently,
The drive voltage can be sufficiently applied to the liquid crystal layer.

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION [Embodiment 1] An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a sectional view of a transmissive liquid crystal display device 13 according to this embodiment of the present invention. However, the transmissive liquid crystal display device 13 sees the display screen from the first substrate side.

The transmissive liquid crystal display device 13 has a first substrate 1, a black matrix 2, a color filter 3, a signal electrode 4, a liquid crystal layer 5, a common electrode 6, a photoconductive layer 7, a second substrate 8, and rib ribs 9. , The discharge space 10, the discharge electrode 11, and the third substrate 12.

The black matrix 2 is formed on the first substrate 1.
And a striped color filter 3 of RGB primary colors parallel to each other, a striped signal electrode 4 made of a transparent conductive material such as ITO (indium tin oxide), and a solid alignment film (not shown). Has been formed. In addition,
The material used for the first substrate 1 and the manufacturing method thereof are the same as those in the related art.

The second substrate 8 is a substrate made of glass, and on the front surface (liquid crystal side), a photoconductive layer 7 in which a thin film of a photoconductor made of ZnO is solidly arranged, and a frame-shaped body made of Ag paste. Common electrode 6 and a solidly arranged alignment film (not shown) are formed.

The first substrate 1 and the second substrate 8 are bonded to each other with a liquid crystal layer 5 made of a liquid crystal material sandwiched therebetween, and are spaced at a constant interval by spacer beads or polymer spacers not shown. It is kept.

As the photoconductor for forming the photoconductive layer 7,
There is no particular limitation as long as it is a material that is substantially transparent under visible light and has an electric resistance value that changes with ultraviolet light, particularly near-ultraviolet light with a wavelength of around 300 to 400 nm. For example, metal oxides of ZnO, TiO ₂ and BaTiO ₃ and their composites, or metal nitrides of GaN and their composites, or OPC (organic photoc
An organic polymer known as an onductor or an inorganic polymer such as polysilane can be used.

The method for forming the thin film is not particularly limited, either.
Sputtering method, EB (electron beam) evaporation method and CV
A method using vacuum such as D (chemical vapor deposition) method or a method such as sol-gel method, solution electrolysis method and hydrothermal synthesis method may be used.

Further, the third substrate 12 is a transparent substrate made of glass, and on the third substrate 12, a rib partition wall 9 made of glass extending in a direction orthogonal to the signal electrodes 4 on the first substrate 1 is formed. And a striped discharge electrode 11 made of Ni paste.

The discharge electrodes 11, 11 are provided with a pair of cathode and anode.

A discharge space 10 is formed around the discharge electrode 11, and the second substrate 8 and the third substrate 12 are arranged so that the discharge space 10 and the discharge electrode 11 are parallel to each other.
It is pasted with a glass frit. The discharge space 10 is filled with a gas that can be ionized (converted into plasma) (for example, a He—Xe mixed gas having a pressure of 39996.7 Pa (300 Torr)), and the light emitting unit 15 is included.
(Plasma channel) is formed.

The discharge electrodes 11 and 11 are connected to the discharge space 1
It suffices to be able to discharge at 0, and its arrangement can be appropriately selected.

Specifically, as shown in FIGS. 1 and 2A, both electrodes of the pair of discharge electrodes 11 are formed on either the second substrate 8 or the third substrate 12, You may discharge between two adjacent poles.

Further, as shown in FIG. 2 (b), one pole is provided on the third substrate 12 substantially in the center of the discharge space 10,
The other pole may be arranged between the rib partition wall 9 and the third substrate 12. With such an arrangement, one of the electrodes can be shared by the adjacent discharge spaces 10.

Further, as shown in FIG. 2 (c), a pair of discharge electrodes 11 may be formed on the second substrate 8 and the third substrate 12 one by one for the face-to-face discharge.

Next, the common electrode 6 of the transmissive liquid crystal display device 13 in the above embodiment will be described with reference to FIGS. 3 (a) and 3 (b). The common electrode 6 is the light emitting unit 1.
5 is an electrode for supplying a common voltage to the pseudo electrode 31 (described in detail later) formed on the photoconductive layer 7 by irradiation with ultraviolet light. The arrangement of the common electrode 6 can be appropriately selected depending on the purpose.
For example, as shown in FIG. 3A, a stripe-shaped ultraviolet light irradiation region 30 of the photoconductive layer 7 outside the display region 20 of the liquid crystal display device and irradiated with ultraviolet light from the light emitting unit 15 (detailed later). Can be formed), or as shown in FIG.
As shown in FIG.
May be formed in stripes parallel to each other and extending in the direction.

In the case of FIG. 3 (a), since the common electrode 6 is formed outside the display region 20, there is no great limitation on the material and shape. For example, metal paste or conductive polymer material is screen-printed or dispenser. Since it only needs to be applied by, the arrangement is extremely low in cost.

In the case of FIG. 3B, since the common electrode 6 is formed in the display region 20, there is some restriction (for example, the aperture ratio is reduced, and the display image has unevenness unless it is formed in a uniform shape). However, since the electric resistance value (as one line) of the photoconductive layer 7 at the time of irradiation with ultraviolet light can be lowered, the arrangement is suitable for larger size.

The common electrode 6 formed in the display area 20 is formed in parallel with the pseudo electrode 31.
According to this configuration, the distance between each part of the pseudo electrode 31 and the common electrode 6 is shortened, and the electric resistance value of the photoconductive layer 7 (pseudo electrode 31) is reduced. The applied voltage to each part can be reduced. In other words, with a drive voltage of the same magnitude, a larger pseudo electrode 31
A voltage can be applied to the liquid crystal display device, and the liquid crystal display device can be upsized.

The common electrode 6 formed in the display region 20 is provided on the photoconductive layer 7 and is formed so as to overlap the pseudo electrode 31. According to this configuration, each part of the pseudo electrode 31 and the common electrode 6 are directly and electrically connected, that is, the distance between each part of the pseudo electrode 31 and the common electrode 6 is shortened, and the same as above. The effect is obtained.

Further, it is preferable that a pixel electrode 62 (FIG. 6B) that defines a pixel region is formed on the region of the photoconductive layer 7 where the pseudo electrode 31 is formed.

Here, the intersection area of the stripe-shaped pseudo electrode 31 formed by irradiating the photoconductive layer 7 with ultraviolet light from the discharge space 10 of the light emitting portion 15 and the signal electrode 4 orthogonal to the pseudo electrode 31 is the pixel area. Become. However, since the pseudo electrode 31 and the signal electrode 4 are provided so as to sandwich the liquid crystal layer 5, the pseudo electrode 31 and the signal electrode 4 are not in contact with each other and the pixel region (shape of the pixel) thereof is not defined.

Therefore, using a transparent conductive material such as ITO, the pixel electrode 6 is formed as an electrode portion in the intersection region on the photoconductive layer 7.
Form 2. As a result, the shape of the pixel electrode 62 becomes a pixel shape (pixel area), and the pixel area can be defined. Further, by forming the pixel electrode 62, it is possible to
Since the electric resistance value of the pseudo electrode 31 as a line can be reduced, power consumption can be reduced.

Further, it is preferable that the width of the pixel electrode 62 in the second direction is wider than that of the pseudo electrode 31. According to this, the voltage can be applied to a region other than the ultraviolet light irradiation region 30 (pseudo electrode 31) in the photoconductive layer 7, so that a region that cannot normally be used as a pixel region (for example, a region on the rib partition 9). ) Can also be used as a pixel area. As a result, higher brightness display can be performed.

The pseudo electrode 3 formed on the photoconductive layer 7
The width of 1 (corresponding to the opening width of the discharge space 10 in FIG. 1) may be sufficiently smaller (may be thinner) than one side of the pixel electrode 62. That is, when the pixel electrode 62 is formed on the photoconductive layer 7, the pseudo electrode 31 serves not as an electrode but as a wiring, and thus the pixel electrode 62 is not always required.
It does not have to be formed with the same width as.

As shown in FIG. 4, the transmissive liquid crystal display device 13 has discharge electrodes 11 formed on the second substrate 8 and is excited by ultraviolet light on the third substrate 12 to emit white light (visible light). A phosphor 71 that emits light) may be provided. Thereby, the ultraviolet light source for switching and the backlight (white light source) can be shared, and the cost and thickness of the transmissive liquid crystal display device can be reduced.

However, such an ultraviolet light emitting section 15
Is not limited to the above method using the plasma channel, but E
Any method can be selected, such as a method of utilizing a fluorescent display tube that emits light by accelerating thermoelectrons from the L element (organic EL) and the filament and applying them to the phosphor.

Next, the driving principle of the transmissive liquid crystal display device 13 will be described with reference to FIGS. 5 (a) and 5 (b). FIG. 5A shows the ultraviolet light irradiation region 30 at a certain point in time, and FIG. 5B shows a state in which the ultraviolet light irradiation region 30 has moved to the adjacent one.

The discharge space 10 selected at a certain time point
When a pulse voltage is applied to the pair of discharge electrodes 11 in FIG. 1 (FIG. 1), the enclosed gas is ionized (plasmaized), and ultraviolet light extending in stripes is emitted from the light emitting unit 15. When this ultraviolet light passes through the second substrate 8 and enters the photoconductive layer 7, a stripe-shaped ultraviolet light irradiation region 30 is formed on the photoconductive layer 7. At this time, the electric resistance value of the photoconductor in the ultraviolet light irradiation region 30 is lowered and the photoconductor becomes conductive, so that a stripe-shaped conductor (pseudo electrode 31) is formed.

As described above, the photoconductive layer 7 on the second substrate 8 is formed.
Since the pseudo electrode 31 formed in 1 is in electrical contact with the common electrode 6 in the connection portion 32 where the common electrode 6 is laminated, the pseudo electrode 31 has the same potential as the common electrode 6. Therefore, a potential difference is generated between the pseudo electrode 31 and the signal electrode 4 on the first substrate 1. Therefore, the potential difference drives the liquid crystal layer 5 in the liquid crystal drive region 33, which is the intersection of one pseudo electrode 31 and one signal electrode 4.

Next, when the discharge from the discharge electrodes 11 and 11 is stopped, the ultraviolet light irradiation area 30 is changed to the non-ultraviolet light irradiation area 3.
It becomes 4. That is, the electric resistance value of the photoconductive layer 7 in the region where the pseudo electrode 31 was formed rises and returns to the non-conductive state. As a result, however, the region that was the liquid crystal drive region 33 (FIG. 5A) serves as the drive state holding region 35 and holds the applied voltage, so that the state of the liquid crystal is maintained.

From the above, according to the liquid crystal display device 13, as an electrode for applying a drive voltage to the liquid crystal,
Since the photoconductive layer 7 can be used directly, the structure of the electrode can be simplified.

Therefore, it is possible to realize a transmissive liquid crystal display device having a simpler structure than the conventional one, and it is possible to prevent the material cost, the number of manufacturing steps, and the yield from decreasing.

[Second Embodiment] The following will describe another embodiment of the present invention in reference to FIG. The transmissive liquid crystal display device according to the present embodiment is
Since it is applied to the transmissive liquid crystal display device 13 described in Embodiment 1 with reference to FIGS. 1 to 5,
About this component, the same reference numerals are added and quoted,
The description is omitted. Further, the terms defined in the first embodiment will be used in accordance with the definitions also in the present embodiment unless otherwise specified.

As shown in FIGS. 6A and 6B, the transmissive liquid crystal display device has a front surface of the first substrate 1 and a third substrate 12.
A polarizing plate 60 and a polarizing plate 61 are attached to the back surface of the. A backlight 63 (mainly a cold cathode tube is used) is provided on the back surface of the polarizing plate 61. Note that FIG. 6B is a cross-sectional view of a portion where the second substrate 8 and the third substrate 12 are bonded to each other along the line A.

As shown in FIG. 6A, dot-shaped pixel electrodes 62 made of a transparent conductive material are formed on the photoconductive layer 7. That is, one pixel electrode 62 is
One pixel electrode 62 is formed at each intersection (liquid crystal drive region 33 in FIG. 5) of the ultraviolet light irradiation region 30 (pseudo electrode 31) of the book and one signal electrode 4. The area of the intersection may be referred to as a dot.

Further, each discharge space 10 is provided such that its longitudinal direction is orthogonal to the longitudinal direction of each RGB pixel of the color filter 3, and is arranged so as to form a pair with each pixel electrode 62.

A stripe-shaped discharge space 10 is formed on the back surface of the third substrate 12 (the surface opposite to the liquid crystal layer 5), and a pair of discharge electrodes 11 and 11 are arranged therein. ing. That is, as shown in FIG. 6B, in the present embodiment, the second substrate 8 and the rib partition wall 9 of the first embodiment are arranged.
And (FIG. 1) are integrally formed as the second substrate 8. Then, a voltage (pulse voltage) of about 350 V is applied to the discharge electrodes 11 arranged in one discharge space 10.
When the voltage is applied, the discharge electrodes 11 and 11 are discharged, the gas in the discharge space 10 is ionized (plasmaized), and ultraviolet light (ultraviolet light) is emitted. This ultraviolet light enters the photoconductive layer 7 to form the stripe-shaped pseudo electrode 31.

The pseudo electrode 31 has a pixel electrode 62.
Since the (dot-shaped transparent electrode) is connected, the common voltage supplied from the common electrode 6 is applied to the pixel electrode 62, and this pixel electrode 62 becomes the display area. The pseudo electrode 31 has the same potential as the common electrode 6. At this time, when a voltage is applied to the signal electrode 4 on the first substrate, a region sandwiched between the pixel electrode 62 and the signal electrode 4 facing the pixel electrode 62 (intersection of the signal electrode 4 and the pseudo electrode 31; The liquid crystal in the liquid crystal drive area 33 in FIG. 5) is driven.

Next, when the voltage application to the discharge electrodes 11 and 11 during discharge is stopped and a pulse voltage is applied to the discharge electrodes 11 and 11 arranged in the adjacent discharge space 10, a new pseudo electrode 31 and a signal are generated. The liquid crystal in the area sandwiched between the electrodes 4 is driven. At this time, the discharge space 1 in which the voltage application is stopped
The pseudo electrode 31 on the front surface of 0 disappears when the irradiation of the ultraviolet light is stopped, but the liquid crystal in the drive state holding region 35 holds the drive state regardless of the potential change of the signal electrode 4.

As described above, according to the above-mentioned transmission type liquid crystal display device, by repeating the scanning of the discharge electrode 11 and the voltage application to the signal electrode 4, the application and the retention of the signal voltage to the liquid crystal are repeated for each pixel. , The image is displayed.

[Third Embodiment] The following will describe still another embodiment of the present invention in reference to FIG. Since the transmissive liquid crystal display device according to the present embodiment is applied to the transmissive liquid crystal display device described in Embodiment 2 with reference to FIG. 6, the same reference numerals are used for these components. It is attached and quoted, and its description is omitted. Further, the terms defined in the first and second embodiments are used according to the definitions in the present embodiment unless otherwise specified.

As shown in FIG. 7A, the transmissive liquid crystal display device is the same as the transmissive liquid crystal display device described in the second embodiment, except that the pixel electrode 62 and the common electrode 6 are formed on the photoconductive layer 7.
The polarizing layer 70 is formed so as to sandwich it.

FIG. 7 (b) is a sectional view of a portion where the second substrate 8 and the third substrate 12 are bonded together in the line B.

As shown in FIG. 7B, the discharge space 10 is formed on the front surface (the liquid crystal layer 5 side) of the third substrate 12, and the stripe-shaped discharge electrodes 11 are formed on the back surface of the second substrate 8.
11 is arranged so as to enter the discharge space 10. That is, the second substrate 8 and the rib partition wall 9 (FIG. 1) of the first embodiment are integrally formed as the second substrate 8.

Then, the phosphor 71 is applied to the inner wall of the discharge space 10, for example, the rear surface side. This phosphor 71
The material is not particularly limited as long as it is a material that emits white light by exciting ultraviolet light generated by the discharge of the discharge electrodes 11.

Further, the second substrate 8 and the third substrate 12 are attached by glass frit so that the discharge space 10 and the discharge electrode 11 are parallel to each other, and the formed discharge space 10 is ionized ( A gas capable of being turned into plasma is enclosed and the light emitting unit 15 (light emitting device) is formed.

Here, in the above-mentioned transmission type liquid crystal display device, the polarizing layer (polarizing element) of the light emitting section 15 and its arrangement have a preferable structure to be used as the light emitting section 15 (ultraviolet light emitting section) and the backlight. There is.

On the other hand, in the conventional liquid crystal display device, a polarizing element (polarizing plate) in which a dichroic dye (iodine, azo dye, etc.) is adsorbed on a polymer film and oriented in a uniaxial direction is often used as a polarizing element. It was being done. Then, the polarizing plates are arranged so as to sandwich the substrate in a pair. Of course, in a normal liquid crystal display device, there is no problem in disposing such a polarizing plate.

However, in the transmissive liquid crystal display device, since the light emitting section 15 is used as an ultraviolet light emitting section and a backlight, the arrangement of this polarizing plate is not realistic. That is, when the photoconductive layer / polarizing plate / ultraviolet light emitting portion are arranged in this order when viewed from the liquid crystal layer 5 side, most of the ultraviolet light is absorbed by the polarizing plate, and good driving characteristics cannot be obtained. Also,
When the polarizing plate / photoconductive layer / ultraviolet light emitting part are arranged in this order,
Due to the thickness of the polarizing plate, the voltage of the driving electrode is not sufficiently applied to the liquid crystal layer, and good driving characteristics cannot be obtained.

Therefore, in the above-mentioned transmission type liquid crystal display device, at least one of the polarizing elements should be a thin film (polarizing plate) which is composed of a polymer thin film orientated in a certain direction or a polymer material mixed with a coloring agent. A colorant is mixed with a polymer material to form a thin film (polarizing plate) oriented in a certain direction, and the thin film is arranged in the order of a polarizing element / photoconductive layer / ultraviolet light emitting part.

Specifically, the polarizing layer 70 is formed on the front surface of the second substrate 8 with the pixel electrode 62 and the common electrode 6 interposed therebetween. The material of the polarizing layer 70 is, for example, polarizing ink manufactured by Nakan Co., Ltd., but the material is not limited to this as long as it has a similar function. An alignment film material is applied on the polarizing layer 70, and an alignment treatment is applied.

Similarly, the first substrate 1 subjected to the alignment treatment,
The second substrate 8 is bonded via the spacer beads so that the stripe direction of the signal electrode 4 and the stripe direction of the discharge electrode 11 are orthogonal to each other. Then, finally, a liquid crystal material is injected into the gap between the first substrate 1 and the second substrate 8, and the polarizing plate 60 is attached only to the front surface of the first substrate 1.

In the transmissive liquid crystal display device, of the ultraviolet rays (ultraviolet rays) generated from the ionized (plasmaized) gas, those emitted to the front form the pseudo electrode 31, and the remaining ultraviolet rays are fluorescent. It is incident on the body 71 to generate white light.

As described above, according to the transmissive liquid crystal display device, the single light emitting section 15 has both the functions of the striped ultraviolet light emitting device and the visible light emitting device (backlight).
The liquid crystal display device can be provided in (same element). Therefore, it is possible to provide a liquid crystal display device which is low in cost and thin due to its simple structure. Of course, also in the transmissive liquid crystal display device, by repeatedly scanning the discharge electrode 11 and applying a voltage to the signal electrode 4, application and holding of a signal voltage to the liquid crystal is repeated for each pixel to display an image.

Further, the present embodiment does not limit the scope of the present invention, and various modifications can be made within the scope of the present invention. For example, the following configurations can be made.

The liquid crystal display device according to the present invention comprises a pair of substrates arranged in parallel with each other, an ionizable gas is sealed between the pair of substrates, and the phosphor is provided on one side of the pair of substrates. And a stripe-shaped discharge electrode parallel to each other is formed on one side or both sides of the substrate, and a stripe-shaped discharge region is formed by applying a discharge voltage to the discharge electrode in sequence. The ultraviolet light emitting device and the visible light emitting device may be combined.

Further, in the liquid crystal display device according to the present invention, by providing a phosphor in the discharge space of the light emitting portion (light emitting device), the light emitting portion can also serve as a backlight (white light source). In this respect, depending on the selection of the phosphor, the light emission does not stop immediately when the discharge is stopped, but the light is emitted for a while even after the discharge is stopped, that is, the afterglow can be used, so that the discharge space after the discharge can be used. It is also possible to recognize the display screen at the position.

Further, since the rib partition wall of the light emitting portion is made of glass, the ultraviolet light generated by the discharge of the discharge electrode can pass through the rib partition wall. Therefore, when a certain discharge line is discharged, the ultraviolet light generated in that discharge line passes through the rib partition, and the phosphors in the front and rear lines are also made to emit light. As a result, the white light emitting line becomes wider than the width of one discharge line (width in the longitudinal direction of the discharge space). Therefore, as a certain discharge line moves in sequence, the wide white light emitting line moves in sequence.

Further, the liquid crystal display device according to the present invention is a liquid crystal display device in which at least a liquid crystal layer is sandwiched by a pair of polarizing elements, and at least one of the pair of polarizing elements is oriented in a fixed direction. A polymer thin film or a thin film obtained by mixing a polymeric material with a coloring agent, or a thin film obtained by mixing a polymeric material with a coloring agent and orienting the same in a fixed direction; and the first substrate and the second substrate. It may be configured so as to be arranged at a position sandwiched between and.

In each of the above embodiments, the discharge space 10 has a rectangular shape with a constant cross section in the longitudinal direction,
The case where the photoconductive layer 7 is provided in the shape of a groove having a rectangular opening for irradiating ultraviolet light has been described, but the present invention is not limited to this. For example, in the cross section of the discharge space 10 in the longitudinal direction, the wall surface facing the opening for irradiating the ultraviolet light may be formed in an arc shape or a parabola shape. Further, the shape of the opening for irradiating the ultraviolet light may be a constricted shape for each pixel, that is, a shape in which only the wiring that connects the pixel areas is formed between the pixel areas as the pseudo electrode 31.

Here, the opening shape of the discharge space 10, that is, the planar shape of the pseudo electrode 31, the shape of the common electrode 6, the presence / absence of the pixel electrode 62, and the shape can be appropriately selected in accordance with these combinations. is there.

3 (a) and 3 (b) show the case where the same voltage is applied to all the pseudo electrodes 31 via the common electrode 6, the electrodes supplying the voltage are the pseudo electrodes 3
It is also possible to provide each one and control each pseudo electrode 31.

[0111]

As described above, the liquid crystal display device of the present invention includes the first substrate, the second substrate, the liquid crystal layer sandwiched between the first substrate and the second substrate, and the first substrate. Signal electrodes formed on the liquid crystal layer side of one substrate and parallel to each other extending in a first direction; a photoconductive layer formed on the liquid crystal layer side of the second substrate and conducting by irradiation of ultraviolet light; The layer is provided with a light emitting unit that irradiates ultraviolet rays so as to form mutually parallel pseudo electrodes extending in a second direction orthogonal to the first direction.

Therefore, when the photoconductive layer is irradiated with ultraviolet light so as to be orthogonal to the first direction of the signal electrode, the pseudo electrode is also formed to be orthogonal to the signal electrode, so that the signal electrode and its pseudo electrode are formed. An intersection is formed at and, and a voltage is applied to the liquid crystal at the intersection.

Therefore, since the photoconductive layer can be directly used as an electrode for applying a drive voltage to the liquid crystal, the structure of the electrode can be simplified.

Therefore, it is possible to realize a transmissive liquid crystal display device having a simpler structure than the conventional one, and it is possible to prevent the material cost, the number of manufacturing steps, and the yield from being reduced.

Further, in the liquid crystal display device of the present invention, the light emitting section sequentially emits light so that the pseudo electrodes are sequentially formed.

Therefore, the liquid crystal at the intersection of the pseudo electrode and the signal electrode orthogonal thereto can be driven sequentially,
An effect that an image can be displayed is produced.

Further, the liquid crystal display device of the present invention has a structure in which the common electrode for supplying a common voltage to the pseudo electrode is formed outside the display region.

Therefore, there is no great limitation on the material and shape of the common voltage, and for example, a metal paste or a conductive polymer material may be applied by screen printing or a dispenser, which is an extremely low cost method. There is an effect that becomes.

Furthermore, the liquid crystal display device of the present invention has a structure in which the common electrode is formed in the display region.

Therefore, the electric resistance of the photoconductive layer (pseudo-electrode) (as one line) at the time of irradiation with ultraviolet light can be further lowered, so that there is an effect that it becomes a method suitable for larger size. .

Further, the liquid crystal display device of the present invention has a structure in which the common electrode formed in the display region is formed in parallel with the pseudo electrode.

Therefore, the applied voltage from the common electrode to each part of the pseudo electrode can be further reduced. In other words, it is possible to apply a voltage to a larger pseudo electrode with the same drive voltage. Therefore, it is possible to increase the size of the liquid crystal display device.

Further, the liquid crystal display device of the present invention has a structure in which the common electrode is formed on the photoconductive layer so as to overlap the pseudo electrode.

Therefore, further, each part of the pseudo electrode and the common electrode are directly and electrically connected, that is, the distance between each part of the pseudo electrode and the common electrode is shortened, and the same effect as above is obtained. Is obtained.

Further, the liquid crystal display device of the present invention has a structure in which a pixel electrode defining a pixel region is formed on the photoconductive layer.

Therefore, it is possible to further reduce the electric resistance value of the photoconductive layer (pseudo electrode) (as one line) at the time of ultraviolet light irradiation, and it is possible to obtain a display device with low power consumption.

Further, in the liquid crystal display device of the present invention, the width of the pixel electrode in the second direction is wider than that of the pseudo electrode.

Therefore, a region that cannot normally be used as a pixel region (for example, a region on a rib partition wall) can also be used as a pixel region. Therefore, there is an effect that a display with higher brightness can be performed.

Further, in the liquid crystal display device of the present invention, the light emitting portion is provided for each of the pseudo electrodes at a position facing the pseudo electrode.

Therefore, further, the ultraviolet light from the light emitting portion is in the form of stripes, and the photoconductive layer at the position facing the discharge space of the light emitting portion has stripe-shaped pseudo electrodes parallel to each other and extending in the direction orthogonal to the signal electrodes. There is an effect that can be formed.

Further, in the liquid crystal display device of the present invention, the light emitting section is provided with a discharge space in which an ionizable gas is sealed, and a discharge electrode is provided in the discharge space.

Therefore, further, by emitting ultraviolet light,
There is an effect that it can be used to form a pseudo electrode on the photoconductive layer.

Further, the liquid crystal display device of the present invention has a structure in which a phosphor is provided on the inner wall of the discharge space.

With the above structure, the light emitting section can also serve as an ultraviolet light emitting device and a visible light emitting device (backlight), and a thinner and lower cost liquid crystal display device can be realized. Has the effect.

Further, the liquid crystal display device of the present invention has a structure in which a polarizing layer is provided between the photoconductive layer and the liquid crystal layer.

Therefore, there is an effect that the ultraviolet light can be efficiently used and the driving voltage can be sufficiently applied to the liquid crystal layer.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a transmissive liquid crystal display device according to an embodiment of the present invention.

2 (a), (b) and (c) are cross-sectional views showing an arrangement example of discharge electrodes of the transmission type liquid crystal display device shown in FIG.

3A and 3B are plan views showing an arrangement example of common electrodes of the transmissive liquid crystal display device shown in FIG.

4 is a cross-sectional view showing a light emitting portion of the transmissive liquid crystal display device shown in FIG.

5A and 5B are explanatory diagrams showing driving of the transmissive liquid crystal display device shown in FIG.

FIG. 6A is an explanatory diagram showing a schematic configuration of a transmissive liquid crystal display device according to another embodiment of the present invention, and FIG.
[Fig. 4] is a cross-sectional view of a portion where the second substrate and the third substrate are bonded together in line A of (a).

FIG. 7A is an explanatory diagram showing a schematic configuration of a transmissive liquid crystal display device according to still another embodiment of the present invention,
(B) is a cross-sectional view of a bonded portion of the second substrate and the third substrate along line B of (a).

FIG. 8 is a cross-sectional view of a transmissive liquid crystal display device according to a conventional technique.

[Explanation of symbols]

1st substrate 4 signal electrodes 5 Liquid crystal layer 6 common electrode 7 Photoconductive layer 8 Second substrate 10 discharge space 11 discharge electrode 15 Light emitting part 20 display area 31 Pseudo electrode 62 pixel electrodes 70 Polarizing layer 71 phosphor

Continued front page    F-term (reference) 2H089 HA14 HA38 JA07 JA10 JA11                       QA11 QA12 QA16                 2H091 FA07Y FA43Z FB02 FB06                       FB11 FC23 GA14 LA11 LA12                       LA16 LA30                 2H092 KA08 KA19 KB05 LA03 LA05                       LA12 NA26 NA27 NA28 NA29

Claims (12)

[Claims] 1. A first substrate, a second substrate, a liquid crystal layer sandwiched between the first substrate and the second substrate, and a first liquid crystal layer formed on the liquid crystal layer side of the first substrate. Parallel to each other in the direction, a photoconductive layer formed on the liquid crystal layer side of the second substrate and conductive by irradiation with ultraviolet light, and a second photoconductive layer that is orthogonal to the first direction. And a light emitting section for irradiating ultraviolet light so as to form mutually parallel pseudo electrodes extending in the direction of the liquid crystal display device. 2. The liquid crystal display device according to claim 1, wherein the light emitting portion sequentially emits light so as to sequentially form the pseudo electrodes. 3. The liquid crystal display device according to claim 1, wherein a common electrode for supplying a common voltage to the pseudo electrode is formed outside the display area. 4. The liquid crystal display device according to claim 1, wherein a common electrode for supplying a common voltage to the pseudo electrode is formed in a display region. 5. The liquid crystal display device according to claim 4, wherein the common electrode is formed in parallel with the pseudo electrode. 6. The liquid crystal display device according to claim 3, wherein the common electrode is formed on the photoconductive layer so as to overlap the pseudo electrode. 7. A liquid crystal display device according to claim 1, wherein a pixel electrode defining a pixel region is formed on the photoconductive layer. 8. The liquid crystal display device according to claim 7, wherein the pixel electrode has a width in the second direction wider than that of the pseudo electrode. 9. The liquid crystal display device according to claim 1, wherein the light emitting portion is provided for each of the pseudo electrodes at a position facing the pseudo electrode. 10. The light-emitting portion has a discharge space in which an ionizable gas is sealed, and a discharge electrode is provided in the discharge space. The liquid crystal display device according to item. 11. The liquid crystal display device according to claim 1, wherein a phosphor is provided on an inner wall of the discharge space. 12. A polarizing layer is provided between the photoconductive layer and the liquid crystal layer.
2. The liquid crystal display device according to any one of 1.