Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
2000-10-06
2003-05-20
Kim, Robert H. (Department: 2882)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S585000, C313S495000
Reexamination Certificate
active
06566812
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a plane discharge scheme AC type plasma display panel, and more particularly, to a cell structure of a plasma display panel for adjusting white balance.
2. Described of the Related Art
Recent years, a plasma display panel (referred to “PDP” hereinafter) of a plane discharge scheme AC type as an oversize and slim display for color screen has been received attention, which is becoming widely available.
FIG. 18
is a perspective view illustrating a configuration of a conventional AC type PDP when a front glass substrate
1
is separated from a back glass substrate
4
.
In
FIG. 18
, a plurality of row electrode pairs (X′, Y′) is arranged on the backside of the front glass substrate
1
and covered with a transparent dielectric layer
2
on a backside of which a transparent protective layer
3
made of MgO is formed.
The row electrodes X′ and Y′ are respectively comprised of wider transparent electrodes Xa′ and Ya′ each of which is formed of a transparent conductive film made of ITO (Indium Tin Oxide) or the like, and narrower bus electrodes Xb′ and Yb′ each of which is formed of a metal film, complementary to conductivity of the transparent electrode. The row electrodes X′ and Y′ are provided with respective projections Xa″ and Ya″ which are formed opposite to each other spaced at regular intervals, and alternating in the column direction such that the projections Xa″ and Ya″ oppose each other with a discharge gap g′ in between.
Each row electrode pair (X′, Y′) forms a display line (row) of matrix display.
A plurality of column electrodes D′ is arranged on the display surface side of the back glass substrate
4
to extend in a direction perpendicular to the row electrode pair (X′, Y′). A band-shaped partition wall
5
is interposed each between the column electrodes D′ to extend in parallel to other partition walls
5
. And also, phosphor layers
6
R,
6
G and
6
B in red (R), green (G) and blue (B), respectively, which comprise the three primary colors, are formed in order in the column direction to overlay side faces of the partition walls
5
and the column electrode D′.
The front glass substrate
1
and the back glass substrate
4
having the above configuration are disposed in parallel and opposite to each other with an interposition of a discharge space. A discharge gas of a mixture of neon and xenon or the like is filled hermetically between the front glass substrate
1
and the back glass substrate
4
.
In this manner, in each display line L, the discharge space is defined by the partition walls
5
at intersections of the column electrodes D′ and the row electrode pair (X′, Y′). This results in defining each discharge cell which serves as a unit light emitting area as described below.
An image is formed in the above AC type PDP as follows.
First, through address operation, the discharge is produced selectively between the row electrode pair (X′, Y′) and the column electrodes D′ in the discharge cells respectively formed with the phosphor layers
6
R,
6
G and
6
B, to scatter lighted cells (the discharge cells are formed with wall charge on the dielectric layer
2
) and nonlighted cells (the discharge cells are not formed with wall charge on the dielectric layer
2
), over the panel in response to an image to be displayed.
After the address operation, in all the display lines L, the discharge sustain pulse is applied alternately to the row electrode pairs (X′, Y′) in unison, and thus the plane discharge is produced in the lighted cells on every application of the discharge sustain pulse.
In this manner, the plane discharge in each lighted cell generates ultraviolet light, to excite the phosphor layers
6
R and/or
6
G and/or
6
B formed in the lighted cell to emit light, resulting in displaying the image.
The aforementioned AC type PDP has outstanding properties to reduce thickness of a display and provide a color screen display with a high quality image.
In the conventional AC type PDP as explained above, the phosphor layers
6
R,
6
G and
6
B formed in the respective discharge cells for displaying the three primary colors of red (R), green (G) and blue (B), differs in brightness of emission from one another. Therefore, if the discharge is produced in the discharge cells of respective colors having an equal emission area at the same number of times of the discharge, the display of a white color is difficult.
Therefore, conventionally, white balance (chromaticity of a white color) is adjusted by balancing the luminance of the three primary colors while the number of times of the discharge in each discharge cell is adjusted for each color on the phosphor layer.
However, the conventional method of adjusting the white balance as explained above has disadvantages in which a display gradation varies in each color, and also the number of display gradation levels itself is impaired. In addition, adjusting a display gradation of green having the largest influence over the luminance on screen, causes a disadvantage of reduction in the peak luminance on screen.
For example, if the number of times of the discharge in the discharge cells respectively formed with the phosphor layers
6
R and
6
G is reduced with respect to the number of times of the discharge in the discharge cell formed with the phosphor layer
6
B, the discharge cell of the phosphor layer
6
B can display up to 256 gradation level of the maximum luminance, but the emission luminance in the discharge cells of the phosphor layers
6
R and
6
G is achieved only by gradations lower than 256 gradation level.
As described above, if the adjustment of white balance is performed by adjusting the number of times of the discharge in each discharge cell for each color of the phosphor layer, the display gradations caused by light emission in the discharge cell vary for each color of red, green and blue, resulting in impairment of quality of gradation display.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above problems associated with adjustment of white balance in the conventional AC type PDP as described above.
It is therefore an object of the present invention to provide a Plasma display panel which is capable of appropriately adjusting white balance without reducing each gradation level of the three primary colors of red, green and blue.
To attain the above object, a plasma display panel according to a first invention comprises a plurality of row electrode Pairs extending on a backside of a front substrate in a row direction and arranged thereon in a column direction to form display lines; a plurality of column electrodes extending in the column direction and arranged in the row direction on a face of a back substrate which opposites to the front substrate with interposing a space and constituting a discharge cell at each intersecting position with the row electrode pair in the space formed by the back substrate and the front substrate; and phosphor layers of the three primary colors of red, green and blue, respectively, which are respectively formed in a plurality of the resulting discharge cells in order, which is characterized in that the discharge cell formed with the red phosphor layer, the discharge cell formed with the green phosphor layer and the discharge cell formed with the blue phosphor layer, have a different opening area, opened toward the front substrate, from one another in accordance with each luminance of red, green and blue colors.
The plasma display panel according to the first invention is set such that an area ratio among the opening areas of the respective discharge cells relates with a predetermined relative ratio of luminance of blue, green and red.
According to the first invention, it is possible to adjust a relative emission luminance among the discharge cells during light emission by the plane discharge required
Amemiya Kimio
Torisaki Yasuhiro
Arent Fox Kintner Plotkin & Kahn
Kim Robert H.
Pioneer Corporation
Yun Jurie
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