JPH09273913A - Method for evaluating coated state of object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and efficiently evaluate the coated state of a second object on the surface of a first object by scanning the surface of the first object before and after coating of the second object by a displacement meter, measuring the distances to the surface before and after coating, and comparing them. SOLUTION: A board 21 before coating with fluorescent material is fixed to the predetermined position of a mounting base 51 so that a rib becomes parallel to the directions of arrows Y, Y'. The measuring position and length are set by a keyboard, and a start command is input. A displacement meter 54 is regulated at the distance from the board 21, moved to the measuring position, moved at a predetermined speed across a rib by the set length, and scanned on the board 21. The output signal is stored in the RAM of a microcomputer. Then, the board 21 is delivered from the base 51, the steps of coating and baking the material are executed, and the board 21 is again fixed to the base 51. The measured data is processed by the microcomputer, and the surface profiles before and after the coating are compared.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating the coating state of an object, and more particularly to a plasma display panel (P
DP) phosphor evaluation method.

[0002]

2. Description of the Related Art Conventionally, in a matrix display type PDP which displays characters and figures by a combination of dots (pixels) arranged vertically and horizontally, a surface suitable for displaying a color other than the emission color of discharge gas by a phosphor. A discharge type PDP is known.

FIG. 2 is an exploded perspective view showing an example of a sectional structure of a portion corresponding to one pixel EG of the PDP. The PDP illustrated in FIG. 2 is an AC drive type PDP having a three-electrode structure.
The glass substrate 11 on the display surface side, the pair of display electrodes X and Y extending parallel to each other in the lateral direction, the dielectric layer 17 for AC driving and its protective film 18, and the glass substrate on the back surface side. 21, address electrodes 2 orthogonal to the display electrodes X and Y
2, ribs 29 that are parallel to the address electrodes 22, a phosphor layer 28 for color display, and the like.

A discharge gas for exciting the phosphor layer 28 with ultraviolet rays is enclosed in the internal discharge space 30.
Such a discharge space 30 is defined by the rib 29 in the unit light emitting area EU in the direction in which the display electrodes X and Y extend, and the gap size is defined. The rib 29 is formed of a low melting point glass layer having a thickness (height) h of about 100 to 130 μm.

In the PDP, as shown in the figure, in each of the three unit light emitting regions EU associated with one pixel EG,
A selection discharge cell for selecting display or non-display at the intersection of one display electrode Y and the address electrode 22 is defined,
A main discharge cell (image discharge cell) is defined between the display electrodes near the selective discharge cell.

The phosphor layer 28 is provided between the ribs 29 on the glass substrate 21 on the side opposite to the display electrodes X and Y in order to avoid ion bombardment due to surface discharge, and is generated by surface discharge of the main discharge cells. It emits light when excited by ultraviolet rays. Light emitted on the surface of the phosphor layer 28 (the surface in contact with the discharge space) passes through the dielectric layer 17 and the glass substrate 11 and exits from the display surface.

In the PDP, the emission colors of the phosphor layers 28 corresponding to the three unit emission regions EU are red (R), green (G), and blue (B) in that order (in the figure). The alphabets R, G, and B indicate the emission color). Further, since the display electrodes X and Y are arranged on the display surface H side with respect to such a phosphor layer 28, the transparent conductive film 41 formed of a nest film or the like and the conductive film thereof are formed in order to enhance the display brightness. And a metal film 42 for supplementing the above.

In the PDP 1 having the above-mentioned structure, the glass substrate 11 and 21 are provided with predetermined constituent elements separately, and then the glass substrates 11 and 21 are arranged to face each other to seal the periphery of the gap. It is manufactured by a series of steps of exhausting and filling with discharge gas.

At this time, in the manufacture on the glass substrate 21 side, the screen printing method is usually used to form the phosphor layer 28. The phosphor layer 28 is printed by sequentially printing the phosphor paste for each color in a predetermined pattern using a screen mask (also referred to as a screen type) and then firing it.
Had formed.

[0010]

In order to increase the brightness of display, it is desirable that the surface area of the phosphor layer 28 is as large as possible. That is, the ideal shape of the phosphor layer 28 is
As shown in FIG. 3, the ribs 29 are formed together with the surfaces of the glass substrate 21 (including the surfaces of the address electrodes 22) between the ribs 29.
The shape is such that the side surface of the is thinly covered.

Therefore, the phosphor layer 28 must be formed after the ribs 29 are provided. Usually, the address electrode 2
2 is formed on the glass substrate 21 before the rib 29 is provided.

However, since the rib 29 has a height of about 140 μm, the phosphor paste is printed by dropping the phosphor paste from a screen mask that is lifted by about 140 μm from the surface of the glass substrate 21. The formed area and thickness of 28 may vary, the brightness and color tone of the display become nonuniform, the display quality may be impaired, and the discharge characteristics may become unstable due to the variation of the covering state of the address electrode 22.

However, a display defect caused by such a variation in the coating state of the phosphor is first found in the stage of the display test after the completion of the PDP. Therefore, in order to investigate the cause during the manufacturing process, a method of visually observing the coating state of the phosphor with a microscope is adopted, but with the increase in panel size, the evaluation work is often performed. However, there is a problem that it takes time to reduce the production efficiency of PDP. The present invention has been made in view of such circumstances, and provides a method capable of efficiently evaluating the coating state of a phosphor during the PDP manufacturing process immediately after the formation of the phosphor layer. Is.

[0014]

A method of evaluating a coating state of a second object coated on a part of the surface of a first object, the surface of the first object before and after coating of the second object. To measure the distance to the surface of the first object before and after coating by scanning the displacement gauge, and to evaluate the coating state of the second object based on the comparison result of the measurement data obtained before and after the coating of the second object. The present invention provides a method for evaluating the coating state of an object.

Furthermore, a method for evaluating the coating state of the phosphor coated on the substrate, wherein the substrate surface after coating the phosphor is illuminated with ultraviolet rays, the substrate surface is scanned by a photodetector to detect light. It is intended to provide a coating state evaluation method for an object, which is characterized in that the coating state of a phosphor is evaluated based on an electric signal obtained from a container.

The first object in the first invention may be any solid object, and a specific example thereof is a substrate for PDP having a plurality of parallel ribs on the surface. The second object is a liquid or paste-like object that can be applied to the first object, and as an example thereof, a paste-like object that is applied to form a phosphor layer between ribs provided on the PDP substrate. A phosphor can be used. Also,
The second invention is applied to, for example, a PDP substrate in which the substrate has a plurality of parallel ribs on the surface and a phosphor is applied between the ribs, but the invention is not limited to this. .

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION As an embodiment of the present invention, P
The method of evaluating the phosphor coating state of DP will be described in detail below. First, a process of forming a plurality of parallel ribs on the surface of a substrate and applying a phosphor between the ribs will be described with reference to FIGS. 1 and 2. An address electrode 22 made of, for example, silver and having a thickness of about 20 μm, and a rib 29 made of low-melting glass and having a height h of about 130 μm are provided on the glass substrate 21 by a printing method.

At this time, the address electrode 22 and the rib 29
For printing the silver paste and the glass paste corresponding to, a screen mask (not shown) in which band-shaped openings having a width of, for example, 60 μm are arranged at a constant pitch p (for example, 220 μm) is used. In this case, the width of the address electrode 22 is 60 to 70 μm, and the widths w1 and w2 of the bottom portion and the vicinity of the top of the rib 29 are about 80 μm and 40 μm, respectively.

Next, the step of forming the phosphor layer 28 is started, and the phosphor paste 28a is printed for each emission color in the following procedure. That is, as shown in FIG. 1A, a screen mask 60 provided with openings 61 having a predetermined width at a pitch three times the pitch p is appropriately aligned with the glass substrate 21 to form the ribs 29. Arrange so that they abut.

Then, a phosphor paste 28a in which a phosphor of a predetermined emission color (for example, R) and a vehicle are mixed is dropped between the ribs 29 through the openings 61. At this time,
As the phosphor paste 28a, as described above, the phosphor layer 2
In order to make the film thickness of No. 8 equal to or less than 50 μm, a phosphor having a phosphor content of 10 to 50% by weight is used. The vehicle is composed of a cellulose-based or acrylic-based thickener resin and an alcohol-based or ester-based organic solvent.

In addition, here, the phosphor paste 28a is extruded from the opening 61 toward the glass substrate 21 side so as to almost completely fill the gaps between the ribs 29. For this purpose, the square squeegee 71 is moved in the direction of the arrow M1.

Next, for the other emission colors (G and B), phosphor paste 28a having a phosphor content of 10 to 50% by weight is sequentially filled so as to almost completely fill the gaps between the ribs 29. Printing is performed [Fig. 1 (b)].

Then, the phosphor paste 28a is dried and fired at a temperature of 500 to 600.degree. [Figure 1
(C)]. Note that, for example, (Y, Gd) BO ₃ : Eu ³⁺ is used as the phosphor of which the emission color is R, and Zn ₂ SiO ₄ : Mn is used as the phosphor of which the emission color is G, and the emission color of B is Examples of the phosphor include BaMgAl ₁₄ O ₂₃ : Eu ²⁺
Can be used.

Next, in the first invention, the displacement gauge includes:
For example, a known optical displacement meter that measures the distance to the target by comparing the phase of the reflected modulated wave with the reference wave and radiating the light of the laser diode to the target by high-frequency modulation can be used.

The data processing means for comparing and evaluating the measurement data is composed of, for example, a CPU, a ROM, a RAM and an I / O port.

The means for outputting the processing result is CR
A T, a printer or the like can be used. The data processing means and the output means may be integrally configured by a personal computer.

The ultraviolet light source according to the second invention is, for example, a combination of a laser diode or a monochromatic light emitting diode that emits laser light having a wavelength in the ultraviolet region and a lens that converges the light on a substrate. It can be used.

As the photodetector, if the phosphor to be applied has three colors of R, G, and B, for example, a photodiode or a fort transistor capable of individually detecting light of R, G, and B colors is used. All phosphors have the same color (single color)
If so, a photodiode or a phototransistor that can detect the monochromatic light can be used.

Since the electric signal obtained from the photodetector has a pulse-like waveform representing the coating width of the phosphor, it is possible to determine the overlap and the positional deviation of the adjacent phosphors from the interval of the waveform.

Example (1) FIGS. 4 and 5 are a side view and a front view of an evaluation apparatus used in Example (1). In these figures the substrate 21
The mounting table 51 for mounting the motor is mounted on a Y-axis sliding device 52 that moves in the direction of arrow Y-Y 'by a motor 52a.
It is mounted on an X-axis sliding device 53 that moves in the X ′ direction. Further, the displacement gauge 54 is moved by the motor 55a to the arrow Z-.
The support arm 56 is attached to the Z-axis sliding device 55 that moves in the Z'direction.
Has been fixed through.

FIG. 6 is a block diagram of a control device used in the embodiment (1). A microcomputer 61 having a CPU, a ROM, a RAM and an I / O port incorporated therein has a keyboard 62 for setting various measurement conditions. And the output from the displacement meter 54, data processing is performed, and the motors 52a, 53
a and 55a are driven, and an image and a numerical value are output to the CRT 63.

A method of evaluating the phosphor coating state using this apparatus will be described with reference to the flowchart of FIG. The operator fixes the substrate 21 before applying the phosphor at a predetermined position on the mounting table 51 so that the ribs are parallel to the arrow Y-Y 'direction (step S1), and uses the keyboard 62 to measure the measuring position and the measuring length. (Step S2), then the keyboard 6
A start command is input from 2 (step S3).

As a result, the distance of the displacement gauge 54 from the substrate 21 is adjusted and the displacement gauge 54 moves to the set measurement position (step S4). And displacement meter 5
4 scans the substrate while moving at a constant speed across the rib in the direction of arrow X or X'for a set length.

At this time, the output signal of the displacement meter 54 is stored in the RAM of the microcomputer 61 (step S
5). The steps S4 and S5 are executed for all the positions set in step S2 (step S6).

Next, the worker carries out the substrate 21 from the mounting table 51 (step S7), executes the phosphor coating and baking process (step S9), and then again places the substrate 21 on the mounting table 51 in a predetermined manner. The position is fixed (step S10).
Then, when the steps S4 to S7 are executed, each measurement data is processed by the microcomputer 61, and C
Displayed on RT64.

FIG. 8 shows an example of the display. FIG. 8A
Is a profile obtained from the measurement data of a predetermined portion of the substrate 21 before phosphor coating, where the high peaks represent the cross-sectional shape of the rib 29 and the low peaks represent the cross-sectional shape of the electrode 22.

FIG. 8B shows the substrate 21 after the phosphor is applied.
It is the profile obtained from the measurement data about the same site of. FIG. 8C shows the profiles of FIGS. 8A and 8B superimposed on each other. As a result, the cross section of the phosphor layer is obtained as the hatched portion in FIG. 8C, so that the thickness of the phosphor, the coating region, the coating accuracy, and the like can be evaluated from the shape.

Example (2) FIGS. 9 and 10 are a side view and a front view of an evaluation apparatus used in Example (2). Substrate 2 in these figures
The mounting table 151 for mounting 1 is a Y-axis sliding device 152 that is moved in the direction of arrow YY 'by a motor 152a.
The Y-axis sliding device 152 is mounted on the X-axis sliding device 153 that is moved by the motor 153a in the arrow XX 'direction. In addition, the photodetector 154 and the light source 157
Are fixed via a support arm 56 to a Z-axis sliding device 55 that moves in the direction of arrow ZZ 'by a motor 155a.

The light source 157 has a built-in laser diode for irradiating an ultraviolet light beam and a lens for converging the light beam on the substrate. The photodetector 154 includes an R photodiode 154r and a G photodiode 15
4g, and a B photodiode 154b (see FIG. 11), each of which detects the excitation light from the R phosphor, G phosphor, and B phosphor excited by the light beam of the light source 157.

FIG. 11 is a block diagram of a control device used in the embodiment (2), which includes a CPU, a ROM, a RAM and an I / O.
The microcomputer 161 having a built-in port receives the outputs from the keyboard 162 for setting various measurement conditions and the photodetector 154, processes the data, and outputs the data to the motor 1
52a, 153a, 155a are driven, and CRT
Images and numerical values are output to 163.

A method of evaluating the phosphor coating state using this apparatus will be described with reference to the flowchart of FIG. The operator attaches the ribs 29 to the substrate 21 before applying the phosphor by the arrow YY '.
It is fixed to a predetermined position of the mounting table 151 so as to be parallel to the direction (step S21), the measurement position and the measurement length are set by the keyboard 162 (step S22), and a start command is input from the keyboard 162 (step). S2
3).

Thereby, the substrate 21 of the photodetector 154 is
While the distance from is adjusted, the photodetector 154 moves to the set measurement position (step S24). Then, the photodetector 154 scans the substrate by moving at a constant speed across the rib in the direction of the arrow X or X ′ by the set length.

At this time, the output signal of the photodetector 154 is stored in the RAM of the microcomputer 161 (step S25). The steps S4 and S5 are executed for all the positions set in step S22 (step S26). Each measurement data is displayed on the CRT 164 based on a command from the keyboard 162.

13 and 14 show examples of the display. In these figures, Sr, Sg and Sb are R
Photodiode 154r, G photodiode 1
54g and the output of the B photodiode 154b are shown with time.

When the waveform of FIG. 13 is obtained, since the pulses are regularly arranged, the R, G, and B phosphor layers for R, G, and B are applied with a regular width and a regular pitch between the ribs. It is evaluated as being. When the waveform of FIG. 14 is obtained,
Since the pulse of (b) is overlapped with the pulse of (a) and the width of the pulse of (c) is shortened, G is added to the R phosphor.
The phosphors for B are applied in an overlapping manner, and it is evaluated that the width of the phosphor for B is narrower than the regular width.

[0046]

According to the first invention, the profiles of the surface of the first object before and after the application of the second object are compared, and the cross-sectional shape of the applied second object can be inspected nondestructively. It becomes possible to easily and efficiently evaluate the coating state of the second object on the surface of the first object. According to the second aspect of the present invention, it becomes possible to easily evaluate the overlap and deviation of the phosphors applied to the substrate immediately after the formation of the phosphor layer.

[Brief description of drawings]

FIG. 1 is a process drawing showing a method for manufacturing a PDP according to the present invention.

FIG. 2 is an exploded perspective view showing an example of a cross-sectional structure of a portion corresponding to one pixel of the PDP according to the present invention.

FIG. 3 is a sectional view of an essential part showing an ideal shape of a phosphor layer according to the present invention.

FIG. 4 is a side view of the evaluation device of Example (1).

FIG. 5 is a front view of the evaluation device of Example (1).

FIG. 6 is a block diagram of a control device according to an embodiment (1).

FIG. 7 is a flowchart showing the operation of the embodiment (1).

FIG. 8 is an explanatory diagram showing a display example of the embodiment (1).

FIG. 9 is a side view of the evaluation device of Example (2).

FIG. 10 is a front view of the evaluation device of Example (2).

FIG. 11 is a block diagram of a control device according to an embodiment (2).

FIG. 12 is a flowchart showing the operation of the embodiment (2).

FIG. 13 is a waveform diagram showing a display example of the embodiment (2).

FIG. 14 is a waveform chart showing a display example of the embodiment (2).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Glass substrate (substrate) 22 Address electrode 29 Rib 28 Phosphor layer 28a Phosphor paste 71 Square squeegee

Front page continued (72) Inventor Hiromichi Sasao 5950 Soeda Iriki-cho, Satsuma-gun, Kagoshima Prefecture Kyushu Fujitsu Electronics Limited (72) Inventor Hiroyuki Nakahara 4-1-1, Uedachu, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited (72) Inventor Seiji Ishida 5950 Soeda, Iriki-cho, Satsuma-gun, Kagoshima Prefecture Kyushu Fujitsu Electronics Limited

Claims (4)

[Claims] 1. A second coating applied to a part of the surface of the first object.
A method for evaluating the coating state of an object, comprising measuring the distance to the surface of the first object before and after coating by scanning the surface of the first object before and after coating the second object with a displacement meter,
An application state evaluation method for an object, characterized in that the application state of the second object is evaluated based on a comparison result of measurement data obtained before and after application of the second object. 2. The object according to claim 1, wherein the first object is made of a substrate having a plurality of parallel ribs on the surface, and the second object is made of a phosphor and applied between the ribs. Coating state evaluation method. 3. A method for evaluating the coating state of a phosphor coated on a substrate, the method comprising: scanning the substrate surface with a photodetector while illuminating the substrate surface with the ultraviolet light after the phosphor coating, and performing photodetection. A coating state evaluation method for an object, comprising: evaluating the coating state of a phosphor based on an electric signal obtained from a container. 4. The substrate has a plurality of parallel ribs on its surface,
The method for evaluating the coating state of an object according to claim 3, wherein the phosphor is coated between the ribs.