JPH05303088A - Plasma address display device - Google Patents

Abstract

PURPOSE:To execute a uniform back illumination of the plasma address display device. CONSTITUTION:The device has a structure formed by allowing a flat panel unit 1 and a backlight unit 2 to adhered closely to each other and superposing them. The flat panel unit 1 is provided with a liquid crystal cell substrate 6 having plural signal electrodes 7 arrayed in parallel to each other along the prescribed main surface, a plasma cell substrate 10 which has plasma electrodes 11 orthogonally intersected to the signal electrodes, and arrayed in parallel to each other, and also, in which these plasma electrodes are arranged so as to be opposed to the signal electrodes 7, a liquid crystal layer 9 existing between both these substrates, and a plasma chamber 15 for sealing ionizeable gas, formed between this liquid crystal layer 9 and the plasma cell substrate 10. On the back side of the plasma cell substrate 10, a projecting part 18 for closing guiding way 17 for sealing gas into the plasma chamber 15 is provided. The projecting part 18 is arranged on the outside of an effective light emitting area 21 of the backlight unit 2, and there is no chance to disturn uniformity of a back illuminating light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma addressed display device having a two-layer flat panel structure including a display cell such as a liquid crystal cell and a switching plasma cell. More specifically, the present invention relates to a back lighting structure of a plasma addressed display device.

[0002]

2. Description of the Related Art Conventionally, a switching device such as a thin film transistor is provided for each pixel and is used as a line for increasing the resolution and contrast of a matrix type flat panel display device using a liquid crystal cell or the like. An active matrix addressing method of sequentially driving is generally known. However, in this case, it is necessary to provide a large number of semiconductor elements such as thin film transistors on the substrate, and there is a disadvantage that the manufacturing yield deteriorates especially when the area is increased.

As a means for solving this disadvantage, Buzaku et al. Propose in Japanese Unexamined Patent Publication No. 1-217396 a method of using a plasma switch instead of a switching element such as a thin film transistor. Hereinafter, the configuration of the plasma addressed display device that drives the liquid crystal cell using the switch based on the plasma discharge will be briefly described.
As shown in FIG. 4, this device has a laminated flat panel structure composed of a liquid crystal cell 101, a plasma cell 102, and a common intermediate plate 103 interposed therebetween. Constitute. The plasma cell 102 is formed using a glass substrate 104, and a plurality of parallel grooves 105 are provided on the surface thereof. This groove 105
Extend in the row direction of the matrix, for example. Each groove 1
Reference numeral 05 constitutes a plasma chamber 106 which is sealed by the intermediate plate 103 and is separated into individual parts. An ionizable gas is enclosed in the closed plasma chamber 106. The ridges 107 that separate the adjacent grooves 105 serve as partition walls that partition the individual plasma chambers 106, and also serve as gap spacers for the plasma chambers 106. At the bottom of each groove 105, a pair of parallel plasma electrodes 108 and 109 are provided. The pair of electrodes function as an anode and a cathode, and ionize the gas in the plasma chamber 106 to generate discharge plasma. The discharge area is a row scanning unit.

On the other hand, the liquid crystal cell 101 is composed of a glass substrate 110. The substrate 110 is arranged opposite to the transparent intermediate plate 103 with a predetermined gap, and a liquid crystal layer 111 is filled in the gap. The signal electrode 1 made of a transparent conductive material is formed on the inner surface of the transparent substrate 110.
12 are formed. The signal electrode 112 is orthogonal to the plasma chamber 106 and serves as a column drive unit. Matrix-like pixels are defined at the intersections of the column driving units and the row scanning units, and become the effective display area.

In the display device having such a structure,
Display driving is performed by line-sequentially switching and scanning the plasma chamber 106 in which plasma discharge is performed, and applying an image signal to the signal electrode 112 on the liquid crystal cell side in synchronization with this scanning. When a plasma discharge is generated in the plasma chamber 106, the inside becomes substantially uniformly at the anode potential, and pixel selection is performed for each row. That is, the plasma chamber 106 functions as a sampling switch. When an image signal is applied to each pixel while the plasma sampling switch is in a conductive state, sampling hold is performed, and lighting or extinguishing of the pixel can be controlled. The image signal is held in the pixel as it is even after the plasma sampling switch is turned off.

[0006]

Unlike self-luminous display devices such as CRTs, liquid crystal cells are light-receiving display devices. Therefore, a normal light transmission type is used to obtain sufficient display brightness by performing back lighting. Also in the above-mentioned plasma address display device, although the liquid crystal cell basically constitutes a display screen and the plasma cell is a light emitting device, it is used as an address switching device. Therefore, the amount of emitted light is weak, and in order to obtain a sufficient display brightness, it is desirable that the device is also of a transmissive type and is back-illuminated. In this case, unlike a normal display panel composed of a single liquid crystal cell, the plasma addressed display device is a laminated flat panel in which a liquid crystal cell and a plasma cell are stacked, and it is a problem to perform uniform and compact back lighting. In particular, the plasma cell may be provided with an irregularly shaped sealing portion for sealing the gas, which may impede the uniformity of illumination and compact mounting.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to enable uniform illumination and compact mounting of a plasma addressed display device. In order to achieve such an object, a plasma addressed display device having a direct type back lighting having the following structure was devised. That is, the plasma addressed display device according to the present invention comprises a first substrate or a liquid crystal cell substrate having a plurality of first electrodes or signal electrodes arranged in parallel with each other along a predetermined main surface,
A second electrode having a plurality of second electrodes or plasma electrodes arranged orthogonal to the signal electrodes and parallel to each other and arranged so that the plasma electrodes face the signal electrodes.
The substrate or the plasma cell substrate, the electro-optical material layer such as the liquid crystal layer interposed between the liquid crystal cell substrate and the plasma cell substrate, and the ionizable gas formed between the liquid crystal layer and the plasma cell substrate. It has a flat panel structure consisting of a plasma chamber for This plasma chamber has a so-called open cell structure, and is provided with a gas introduction path for introducing an ionizable gas so as to penetrate the plasma cell substrate. A sealing protrusion is provided at the gas inlet opening on the back side of the plasma cell substrate.
A back light for back-illuminating the display surface is incorporated on the back surface side of the plasma cell substrate. The backlight has an effective light emitting area, and the sealing projection of the gas inlet is arranged outside the effective light emitting area.

The effective light emitting area of the backlight is arranged so as to include the effective display area formed at the intersection of the signal electrode and the plasma electrode, and the light source stored in the backlight is more effective than the sealing protrusion. It is arranged on the light emitting region side.

[0009]

According to the present invention, the effective light emitting region of the backlight is arranged so as to avoid the sealing protrusion of the plasma cell substrate. Therefore, the backlight can be compactly installed in the state of being close to the back surface of the plasma cell substrate, and uniform and uniform illumination can be applied to the display surface without any interruption. If the sealing projection is present in the effective light emitting area, the illumination light is reflected, refracted or blocked, and the effective display area cannot be illuminated uniformly, resulting in a significant deterioration in image quality.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic sectional view showing the configuration of a plasma addressed display device according to the present invention. As shown in the figure, this device has a structure in which a laminated flat panel unit 1 and a backlight unit 2 are stacked, and the flat panel unit 1 is illuminated by a backlight unit 2 from immediately below the back surface.

The flat panel unit 1 has a structure in which a liquid crystal cell 3 and a plasma cell 4 are superposed with a common partition plate 5 interposed therebetween. The partition plate 5 is made of an extremely thin dielectric sheet. The liquid crystal cell 3 is configured by using an upper glass substrate 6, and a plurality of signal electrodes 7 made of a transparent conductive film are formed in parallel with each other on the inner main surface thereof. The glass substrate 6 is adhered to the partition plate 5 using a spacer 8 with a predetermined gap. A liquid crystal layer 9 which is an electro-optical material layer is filled in the gap.

On the other hand, the plasma cell 4 is the lower glass substrate 1
It is configured using 0. A plasma electrode 11 orthogonal to the signal electrode 7 is formed on the inner main surface of the substrate 10. Further, partition walls 12 are formed in the row direction along the upper surface of the plasma electrode 11. The partition plate 5 is at the upper end of the partition wall 12.
It also abuts against and also acts as a spacer. The plasma electrodes 11 are formed in a plurality of stripes at a predetermined interval, and alternately function as the anode A and the cathode K. The plasma electrode 11 is orthogonal to the signal electrode 7 and forms an effective display area 13 at the intersection.

The lower substrate 10 is bonded to the partition plate 5 via a frit seal 14. An airtightly sealed plasma chamber 15 is formed between the two. This plasma chamber 1
Reference numeral 5 is a stripe-shaped partition wall 1 aligned with the plasma electrode 11.
The discharge region 16 is divided by two and individually constitutes a row scanning unit. In the peripheral portion of the glass substrate 10 outside the effective display area 13, each partition wall 12 is partially missing, and the individual discharge areas 16 communicate with each other. Therefore, the plasma cell 4 has a so-called open cell structure. However, an ionizable gas is enclosed inside the plasma chamber 15 which is hermetically sealed as a whole. The gas species can be selected from, for example, argon, helium, neon, xenon or a mixed gas thereof. Encapsulation of gas is performed through an introduction path 17 that penetrates the glass substrate 10. After the gas is filled, the opening of the introduction path 17 provided on the back surface of the glass substrate 10 is glass-sealed, and the protrusion 18 is left. The protrusion 18 is provided outside the effective display area 13.

In the flat panel unit 1 having such a structure, the voltage applied to the plasma electrode 11 is sequentially switched, the discharge region 16 generated between the pair of anodes A and cathodes K is line-sequentially scanned, and synchronized with this scanning. Display driving is performed by applying an image signal to the signal electrode 7 on the liquid crystal cell 3 side. When plasma discharge is generated, the discharge region 16 becomes almost uniformly at the anode potential.
Pixel selection for each row is performed. This pixel is defined at the intersection of a row scanning unit composed of each discharge region and a column scanning unit composed of each signal electrode. The discharge area 16 functions as a sampling switch. When an image signal is applied to each pixel while the plasma sampling switch is on, sampling hold is performed and the molecular arrangement of the liquid crystal layer 9 changes. Even after the plasma sampling switch is turned off, this molecular arrangement change is retained in the pixel as it is. A polarizing plate 1 is provided on both sides of the flat panel unit 1.
9 and 20 are attached, and a change in the molecular arrangement of the liquid crystal layer is taken out as a change in the amount of transmitted light. As described above, the plasma addressed display device according to the present invention is a light transmissive type and requires back lighting in order to obtain good image brightness.

A flat plate type backlight unit 2 is mounted immediately below the flat panel unit 1. The backlight unit 2 includes an effective light emitting area 21 that covers the effective display area 13 and an invalid light emitting area other than the effective light emitting area 21. The effective light emitting area 21 is arranged close to the back surface of the glass substrate 10 in order to uniformly illuminate the effective display area 13 of the flat panel unit 1. At this time, the protruding portion 18 for sealing provided on the back surface of the glass substrate 10 is located in a portion avoiding the effective light emitting region 21. If the protrusions 18 are provided in the effective light emitting area 21, the illumination light is reflected, refracted or blocked, and the effective display area 13 cannot be illuminated uniformly.

FIG. 2 shows a specific configuration example of the backlight unit 2. To facilitate understanding of the present invention, the layout relationship with the effective display area is also shown. The backlight unit 2 is assembled using a housing 22 having a flat rectangular shape. A plurality of cathode tubes 23, which serve as a light source of the backlight, are arranged on the bottom of the housing 22. A light diffusion plate 24 is attached to the upper opening of the housing 22. Further, a light guiding material 25 is filled in the internal space surrounded by the light diffusion plate 24 and the bottom of the housing 22. Note that the light guide material 25 is not always necessary and may be left as a space. The white light emitted from the cathode tube 23 passes through the light guide member 25 and is diffused by the light diffusion plate 24 to obtain surface illumination light having a uniform light intensity distribution. This surface illumination light irradiates the flat panel unit 1 arranged above the effective light emitting area 21. The effective light emitting area 21 covers the effective display area 13 of the flat panel unit 1.

The sealing projection 18 is provided outside the effective display area 13 so as not to disturb the light transmission state in the flat panel unit 1. Protrusions 18 protruding from the glass substrate 10 below the flat panel unit 1
Is inserted into an escape hole 26 provided outside the effective light emitting area 21 of the light guide plate 24 and is housed in the housing 22. Therefore, the flat panel unit 1 is installed in close contact with the backlight unit 2. This protrusion 18 is a housing 22
It is separated from the cathode tube 23, the light guide material 25 and the like by a partition plate 27 provided inside.

Another configuration example of the backlight unit will be described with reference to FIG. Basically, it has a structure similar to that of the backlight unit shown in FIG. 2, and corresponding parts are given corresponding reference numerals to facilitate understanding. A plurality of lamps, for example, cathode tubes 23, which serve as a light source, are arranged at a predetermined interval on the bottom of a housing 22 that constitutes the backlight unit 2. A light diffuser plate 24 is attached to the upper opening surface of the housing 22 so as to cover the cathode tube 23. An escape hole 26 is provided in a part of the light guide plate 24, and the sealing projection 18 is formed.
I am trying to insert. Therefore, the flat panel unit 1 and the backlight unit 2 can be combined with each other in a close contact type. The cathode tube 23 is disposed closer to the effective display area 13 than the projection 18 to prevent the shadow of the projection 18 from appearing in the effective display area 13.

[0019]

As described above, according to the present invention, the sealing projection of the gas introduction passage for enclosing the gas in the plasma chamber provided on the back surface side of the plasma cell substrate is provided with the effective light emitting area of the backlight. It is arranged to be placed outside. With this structure, it is possible to illuminate the effective display area of the liquid crystal cell with uniform surface illumination light without projecting the shadow of the protrusion. In addition, the effective light emitting area of the backlight unit and the effective display area of the flat panel unit can be closely assembled to each other in an aligned state, and the plasma address display device can be compactly assembled.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a basic configuration of a plasma addressed display device according to the present invention.

FIG. 2 is a schematic diagram showing a specific configuration example of a backlight unit used in the present invention.

FIG. 3 is a schematic diagram showing another configuration example of a backlight unit.

FIG. 4 is a schematic perspective view showing an example of a conventional plasma addressed display device.

[Explanation of symbols]

 1 Flat Panel Unit 2 Backlight Unit 3 Liquid Crystal Cell 4 Plasma Cell 5 Partition Plate 6 Glass Substrate 7 Signal Electrode 9 Liquid Crystal Layer 10 Glass Substrate 11 Plasma Electrode 12 Partition Wall 13 Effective Display Area 15 Plasma Chamber 16 Discharge Area 17 Inlet Path 18 Protrusion 19 Polarizing Plate 20 Polarizing Plate 21 Effective Light Emitting Area 22 Housing 23 Light Source (Cathode Tube) 24 Light Guide Plate 26 Escape Hole

Claims (2)

[Claims] 1. A first substrate having a plurality of first electrodes arranged parallel to each other along a predetermined main surface, and a plurality of second electrodes orthogonal to the first electrodes and arranged parallel to each other. And a second substrate having the second electrode arranged so as to face the first electrode, an electro-optical material layer interposed between the first and second substrates, and the electro-optical material. A plasma chamber for enclosing an ionizable gas formed between a layer and the second substrate, and a backlight arranged on the back surface side of the second substrate for back-illuminating the display surface. 2. A plasma address display device characterized in that a sealing projection portion of a gas introduction port for introducing gas into the plasma chamber provided on the back surface side of the second substrate is arranged outside an effective light emitting region of the backlight. 2. The backlight is arranged such that the effective light emitting area includes an effective display area formed at an intersection of the first electrode and the second electrode, and the light source of the backlight is sealed by the light source. 2. The plasma address display device according to claim 1, wherein the plasma address display device is arranged closer to the effective light emitting area than the stop projection portion.