JPH0737510A - Plasma display panel - Google Patents

Abstract

PURPOSE:To lower discharge start voltage to facilitate driving by providing many level-different parts on the surface layer of a magnetium oxide film provided on a dielectric layer coating a display electrode. CONSTITUTION:In a PDP(pasma display panel) 1, an MgO film 18 is composed of a lower layer part 18A uniformly coating a dielectric layer 17 and stripe-state upper layer parts 18B having a width of a 40mum degree and mutually parallel in a line in a line direction. The surface layer surface of the MgO film 18 is made into a corrugated uneven surface wherein the upper layer part 18B is protruded from the upper surface of the lower layer part 18A, and has many level-different parts (s) having a high-low difference of a several mum degree. Consequently in the PDP 1, the surf ace area of the MgO film 18 is increased by the part of the level-different part (s) compared with a case where the surface layer is flat to increase the emission quantity of an secondary electron when given voltage is applied to between display electrodes X and Y to lower discharge start voltage.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a plasma display panel (PDP). The PDP is a self-luminous display device that is advantageous in terms of display brightness, and is used for OA equipment, publication display devices, and the like because it can have a large screen and high-speed display. In particular, the surface discharge type PDP suitable for color display is expanding its application to the field of high-definition video.

[0002]

2. Description of the Related Art In a PDP, a pair of glass substrates are arranged so as to face each other and the peripheral portions of the facing regions of these glass substrates are sealed to form a discharge space having a gap of about several tens to 100 μm inside. It is a display device.

For example, in a matrix display type PDP,
A large number of electrodes are arranged in a grid pattern, and a discharge cell defined at the intersection of the electrodes is selectively caused to emit light, whereby arbitrary figures and characters are displayed.

Now, in an AC drive type PDP in which a voltage pulse having a predetermined crest value is alternately applied to a pair of electrodes defining a discharge cell, the electrodes are covered with a dielectric layer such as low melting point glass, and further, A heat-resistant protective film for protecting the dielectric layer from ion bombardment during discharge is provided on the surface.

Generally, magnesium oxide (MgO) is used as a material for the protective film. Among heat-resistant substances, MgO has a large secondary electron emission coefficient, and has the action of lowering the discharge start voltage and facilitating the driving of the PDP.

In a conventional PDP, a thin film forming method such as a vapor deposition method is used to provide an MgO film having a thickness of about several thousand Å to uniformly cover the dielectric layer.

[0007]

In a surface discharge type PDP in which a pair of electrodes are arranged in parallel with each other on the inner surface of one glass substrate, the discharge space is divided into unit light emitting regions in the extension direction of the electrodes by partition walls. To be done.

Therefore, as the display becomes finer, the discharge space in the unit light emitting region becomes narrower, so that the movement of ions is suppressed and the discharge starting voltage rises, which makes driving difficult.

In view of the above problems, it is an object of the present invention to lower the discharge starting voltage as much as possible to facilitate driving.

[0010]

[Means for Solving the Problems] P according to the invention of claim 1
In order to solve the above problems, the DP has a magnesium oxide film 18 for protecting the dielectric layer 17 covering the display electrodes X and Y and lowering the discharge start voltage, as shown in FIGS. In the plasma display panel 1 described above, the surface layer surface of the magnesium oxide film 18 is configured to have a large number of step portions s.

The PDP according to the invention of claim 2 has a step portion s.
Are provided so as to avoid a boundary portion between the unit light emitting regions EU in the extension direction of the display electrodes X and Y.

[0012]

The surface area of the magnesium oxide film 18 increases by the amount of the step portion s, the amount of secondary electrons emitted when a predetermined voltage is applied between the pair of electrodes X and Y increases, and the discharge start voltage decreases. .

[0013]

1 is an exploded perspective view showing the basic structure of a portion corresponding to one pixel of a PDP 1 according to the present invention, and FIG.
FIG. 3 is an enlarged cross-sectional view showing the main part of PDP1 of FIG.

In FIG. 1, PDP 1 is a surface discharge type PDP having a three-electrode structure, and includes a glass substrate 11 on the display surface H side,
An electrode pair 12 consisting of a pair of display electrodes X and Y extending in the display line direction, a dielectric layer 17 for AC driving, and a MgO film 18 as a protective film for covering the dielectric layer 17 with respect to the discharge space 30. , Glass substrate 21 on the back side, discharge space 30
A plurality of stripe-shaped partition walls 29 that define the gap size of
Address electrodes A and R provided between each partition 29
(Red), G (green), B (blue) three primary color phosphor 28R,
It is composed of 28G, 28B and the like.

The internal discharge space 30 is partitioned by the partition wall 29 in the line direction for each unit light-emission region EU, and the discharge space 30 is neon as a discharge gas that emits ultraviolet rays for exciting the phosphors 28R, 28G, 28B. Xenon (1
(About 15 mol%) mixed with Penning gas is 500
It is enclosed so that the gas pressure is about [Torr]. The dielectric layer 17 and the partition 29 are each formed by printing a low melting point glass paste by a screen printing method and then firing it.

The display electrodes X and Y are composed of phosphors 28R and 28R.
Since it is arranged on the display surface H side with respect to G and 28B,
A band-shaped transparent conductor 41 having a width of about 150 μm for widening the surface discharge and minimizing the shielding of the display light.
And a metal layer 42 having a width of about 60 μm to supplement the conductivity. The transparent conductor 41 is made of a Nesa film (tin oxide film), and the metal layer 42 is made of, for example, a thin film of a three-layer structure of chromium-copper-chrome. The transparent conductor 41 and the metal layer 42 are each formed by the photolithography method.

A selective discharge cell (not shown) for selecting display or non-display of the unit light emitting area EU is defined at each intersection of one of the pair of display electrodes X and Y and the address electrode A. A main discharge cell (not shown) for surface discharge is defined near the discharge cell. As a result, of the phosphors 28R, 28G, and 28B that are continuous in the vertical direction in the figure, a portion corresponding to each unit light-emission region EU can be selectively caused to emit light, and full-color display by combining R, G, and B is possible. Is possible.

Each pixel (dot) EG constituting the display screen
Are three unit light emitting regions E having the same area and arranged in the line direction.
Composed of U. The planar shape of the pixel EG is a square advantageous for image quality, and the planar shape of the unit light emitting region EU is a rectangle long in the vertical direction (for example, a size of about 660 μm × 220 μm).

In displaying, for example, first, a voltage exceeding the discharge start voltage is applied between the display electrode X and the display electrode Y to generate a surface discharge in line units (discharge in the surface direction of the dielectric layer 17). Let When the surface discharge occurs, wall charges having a polarity opposite to the applied voltage are accumulated in the dielectric layer 17 on the display electrodes X and Y, and the wall charges cause a relative discharge between the display electrodes X and Y in each unit light emitting region EU. The cell voltage, which is a potential difference, decreases and the discharge is stopped. Then, for each line
A discharge erasing pulse is applied to the address electrode A selected according to the display pattern to eliminate unnecessary wall charges.

After that, the discharge sustaining voltage is alternately applied to the display electrodes X and Y of each line. As a result, the fluorescent substance 28 is excited by the ultraviolet rays generated by the surface discharge to emit light only in the unit light emitting region EU in which the wall charges have not disappeared. At this time, the brightness of the display is adjusted by appropriately selecting the cycle of applying the sustaining voltage.

As shown in FIG. 2, in the PDP 1, M
The gO film 18 is a lower layer portion 1 that uniformly covers the dielectric layer 17.
8A and a striped upper layer portion 18B having a width of about 40 μm which are parallel to each other arranged in the line direction. Lower part 1
8A is formed by a vapor deposition method, and its thickness is about 5000 Å, which is sufficient to ensure the durability of the dielectric layer 17 as a protective film. The upper layer portion 18B is formed by a thick film method in which MgO paste is pattern-printed and baked, and its thickness is about several μm.

That is, on the surface layer surface of the MgO film 18, the upper layer portion 18B is a wavy uneven surface protruding from the upper surface of the lower layer portion 18A, and a large number of step portions (upper layer portion 18B of the upper layer portion 18B) having a height difference of about several μm. The side surface) s.

As a result, in the PDP 1, the surface area of the MgO film 18 is increased by the step portion s as compared with the case where the surface layer is flat, and a predetermined voltage is applied between the display electrodes X and Y. At this time, the amount of secondary electrons emitted is large and the discharge start voltage becomes low.

However, the stepped portion s for facilitating the discharge is provided so as to avoid the boundary portion between the unit light emitting regions EU in the line direction (the extending direction of the display electrodes X and Y), that is, the vicinity of the partition wall 29. Has been. This is the partition 29
This is a consideration for preventing discharge interference between the unit light emitting regions EU in the line direction when a gap is generated between the partition 29 and the dielectric layer 17 due to variations in height.

FIG. 3 is an enlarged perspective view showing a main part of a PDP 1b according to another embodiment. In FIG. 3, the components corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals regardless of the difference in shape.

In the PDP 1b, the MgO film 18 is composed of a lower layer portion 18A which uniformly covers the dielectric layer 17 and an upper layer portion 18C which is arranged at equal intervals vertically and horizontally and has a plane dimension of about 1 μm square. .

The upper layer portion 18C has a thickness of 5000Å
The thickness is about 1 μm, and is formed by, for example, a lift-off type photolithography method. That is, the lower layer 1
After forming 8A by a vapor deposition method or the like, a photosensitive resin is uniformly applied and patterned to form a partially exposed lower layer portion 1
It is formed by uniformly depositing MgO on the glass substrate 11 including 8 A and removing unnecessary MgO together with the photosensitive resin.

Thus, according to the lift-off, the lower layer portion 1
The upper layer portion 18C can be formed without reducing the thickness of 8A. In addition, by vapor-depositing MgO on the dielectric layer 17 so as to have a thickness of 1.5 μm and partially removing the surface layer portion by strictly controlling the etching conditions, the lower layer portion 18A and the upper layer portion 18C are removed. It is also possible to form them all at once.

Also in the PDP 1b, the surface layer surface of the MgO film 18 is an uneven surface having a large number of step portions (side surface portions of the upper layer portion 18C) s, and the amount of secondary electrons emitted is increased. .

In the above-mentioned embodiments, the surface discharge type PDPs 1 and 1b of the matrix display system are exemplified, but other types of PDs having the MgO film 18 exposed in the discharge space 30 are used.
The present invention can be applied to P, for example, a segment display type surface discharge PDP and a matrix display type opposed discharge PDP.

[0031]

According to the present invention, the discharge start voltage can be lowered as much as possible to facilitate driving.

According to the second aspect of the present invention, it is possible to suppress discharge interference between the unit light emitting regions and stabilize the display.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a basic structure of a portion corresponding to one pixel of a PDP according to the present invention.

2 is a cross-sectional view showing an enlarged main part of the PDP of FIG.

FIG. 3 is an enlarged perspective view showing a main part of a PDP according to another embodiment of the present invention.

[Explanation of symbols]

 1,1b PDP (plasma display panel) 17 Dielectric layer 18 MgO film (magnesium oxide film) s Step portion X, Y Display electrode EU Unit light emitting region

Claims (2)

[Claims] 1. A plasma display panel (1) having a magnesium oxide film (18) for protecting a dielectric layer (17) covering a display electrode (X) (Y) and lowering a discharge firing voltage, A plasma display panel, wherein the surface of the magnesium oxide film (18) has a large number of steps (s). 2. The step portion (s) is the display electrode (X).
The device is provided so as to avoid a boundary portion between the unit light emitting regions (EU) in the extension direction of (Y).
The plasma display panel described.