KR100925275B1 - A phosphor inspector of Plasma Display Panel and the same method - Google Patents

Abstract

An apparatus and method for inspecting a phosphor of a plasma display panel according to the present invention includes an ultraviolet lamp for irradiating ultraviolet rays to a plasma display panel to which a plurality of phosphors are applied to emit respective phosphors, and light emitted from the phosphors emitted by the light emitting means. An apparatus for inspecting a phosphor of a plasma display panel comprising a camera converting a video signal and a microcomputer to read out the video signal converted by the camera and determine whether the phosphor is defective.

Between the phosphor and the camera is disposed a filter that transmits each light differentially according to the wavelength so that the contrast difference of the light emitted from each phosphor is increased, so that the mixture is generated in the phosphor having a brightness difference compared to the peripheral system By inspecting the light emitted from each phosphor, defects such as color mixing and blind spots of the phosphor can be inspected quickly and accurately, and commercial UV lamps can be used to reduce production and maintenance costs. The processing data is reduced, so that high-speed inspection is possible.

PDP bottom plate, address electrode, dielectric layer, barrier rib, phosphor, camera, lens, ultraviolet ray, filter, microcomputer

Description

{A phosphor inspector of Plasma Display Panel and the same method}             

1A to 1C are schematic diagrams illustrating a phosphor forming apparatus by a general phosphor screen printing method;

2 is an image in which the mixed color of a general phosphor is photographed;

3 is a block diagram showing a fluorescent substance inspection apparatus of the plasma display panel according to the prior art,

4 is a configuration diagram showing a phosphor inspection apparatus of a plasma display panel according to the present invention;

5 is a graph showing an emission wavelength band of a general phosphor;

6 is a graph showing the transmittance of the phosphor for each emission wavelength band of the filter according to the present invention;

7 is a graph showing the transmittance of the phosphor for each emission wavelength band of another filter according to the present invention;

8 is an image captured by applying the filter according to the present invention.

<Explanation of symbols for the main parts of the drawings>

120: PDP lower plate 122: address electrode

124: dielectric layer 126: partition wall

128: phosphor 130: camera

132 lens 135 filter

140: UV lamp 150: Micom

The present invention relates to an apparatus and a method for inspecting a phosphor coated on a lower plate of PDP, and more particularly, the light and light difference emitted from each phosphor is provided with filtering means for differential transmission according to the wavelength. The present invention relates to an apparatus and method for inspecting a phosphor of a plasma display panel, which facilitates identification and increases inspection reliability and rapidity.

In general, a plasma display panel (PDP) is widely used as a large-area display device, and as the demands of consumers change to a display device that can provide a large screen while occupying less installation space, Organic EL (Electro luminescent), LCD (Liquid Crystal Display), and other products that can meet the requirements are being developed and commercialized. Among them, PDP has high brightness and large area, and the expectations of users are increasing. There is room for improvement such as high price range and quality deviations between products.

Due to this tendency, quality control for each thought process of the PDP is urgently required. Among them, when the phosphor is not applied correctly on the lower surface of the PDP, mixed color is generated and the image quality is degraded. Is done.

As a method of coating the phosphor on the lower plate of the PDP, there are a screen printing method, a photosensitive paste method, a dry film method and the like.

1A to 1C are schematic diagrams illustrating a phosphor forming apparatus by a general phosphor screen printing method.

In the process of forming the phosphor by the screen printing method, as shown in FIGS. 1A to 1C, the PDP lower plate 20 in which the address electrode 22, the lower dielectric layer 24, and the partition wall 26 are sequentially formed is disposed on the upper side of the stage. A screen mask 35 positioned on the PDP lower plate 20 and selectively opened in a space between the partition walls 26, and using a squeeze rubber 30, red (R) in a paste state, The phosphor 28 of any one of green (R) and blue (R) is inserted.

Subsequently, the screen mask 35 and the phosphor 28 are replaced, and as shown in FIG. 1B, the phosphor 28 is repeatedly inserted to remove the screen mask 35.

When the PDP lower plate 20 is dried, as shown in FIG. 1C, the organic solvent included in the phosphor 28 material evaporates and the volume thereof decreases, thereby decreasing the volume of the phosphor 28 coated only on the surfaces of the lower dielectric layer 24 and the partition wall 26. ) Is completed.

In the embodiment of the prior art, the green phosphor 28G is applied to the lower plate of the PDP to which the red phosphor 28R is applied, and the screen mask 35 is formed when the phosphor 28 is formed by using the screen printing method as described above. When the hole of the screen mask 35 is generated due to scratches or the like on the surface of the surface), the phosphor 28 formed on the lower plate 20 of the PDP has a phosphor 28 as shown in FIG. 2. Mixed color defects are caused by the overlap of, which has a fatal effect on the quality of PDP.

Conventionally, the following technique has been used to inspect the phosphor 28 of the PDP.

First, the PDP lower plate 20 coated with the phosphor 28 is irradiated with ultraviolet rays to capture the emission state of the phosphor 28 through a color camera, and the captured image is displayed on a monitor for visual inspection or microcomputer. Automatic inspection was carried out.

However, when the visual inspection is performed, it takes a lot of time to inspect the PDP lower plate 20 as a whole, resulting in a production bottleneck, and depending on the skill or physical condition of the inspector, the distribution of the quality inspection may occur.

On the other hand, when performing an automatic inspection using a microcomputer that reads the image signal to the color camera to determine whether the phosphor 28 is defective, there is a problem that it is difficult to implement a high-speed automatic inspection due to a large data throughput.

In order to solve the above problems, the PDP phosphor 28 inspection apparatus shown in FIG. 3 (Japanese Patent Laid-Open No. 2000-149781) includes a filter for passing only light of a specific wavelength to the camera in accordance with the light emission characteristics of the phosphor 28. One equipment was developed.

That is, the PDP lower plate 60 is positioned above the stage 50, and an ultraviolet lamp 80 is installed on one side to irradiate ultraviolet rays.

Then, three cameras 70R, 70B, 70G for photographing the same area are provided on one side of the PDP lower plate 60 to which red, green, and blue phosphors 78R, 78G, 78B are coated. Each camera lens is provided with a filter 75 for selectively transmitting only the light of the wavelengths emitted from the red, blue, and green phosphors 78R, 78G, and 78B to the camera 70 selectively.

In addition, a microcomputer 90 is connected to the camera 70 to automatically read an image signal captured by the camera.

Due to the respective filters 75R, 75G and 75B installed as described above, the fluorescent light of the color corresponding to each of the filters 75R, 75G and 75B is transmitted but the fluorescent light of the other colors remains blind. Therefore, if the above blind spots are found during the automatic inspection by the microcomputer 90, it is determined that the defect.

However, since the apparatus for inspecting the PDP phosphor requires a number of cameras and filters corresponding to each phosphor, the structure of the apparatus is complicated, difficulty in maintenance and repair occurs, and inspection of the same region several times according to each phosphor color. There was a problem that the test time is increased because it should be.

Thus, another inspection apparatus proposes a PDP phosphor inspection apparatus (Japanese Patent Laid-Open No. 2000-337998) which recommends the use of a color line sensor camera. However, when the emission intensity of each phosphor obtained by the camera is different, the output signal of the camera is changed. There is a need for an amplifying device or an ultraviolet irradiating device for irradiating a specific wavelength, and a method of obtaining an image signal of each phosphor by a complicated method must be used. Especially, when using a monochrome camera, defects such as blind spots are required. Although there is a problem that detection of the mixed color is impossible.

The present invention has been made in order to solve the above problems of the prior art, and irradiates an ultraviolet lamp that can be easily purchased to emit each phosphor, so that the light and light difference from each phosphor is increased according to the wavelength Accordingly, an object of the present invention is to provide an apparatus and method for inspecting a phosphor of a plasma display panel, which can quickly and accurately inspect whether a phosphor on a PDP lower plate is defective.

A phosphor inspection apparatus of a plasma display panel according to the present invention for realizing the above object is an ultraviolet lamp for irradiating ultraviolet rays to a plasma display panel to which a plurality of phosphors are applied to emit light of each phosphor, and the light emitted by the light emitting means In the phosphor inspection apparatus of the plasma display panel comprising a camera for converting the light emitted from the phosphor into an image signal, and a microcomputer to determine whether the phosphor is defective by reading the image signal converted by the camera,

Between the phosphor and the camera is characterized in that a filter for differentially transmitting each light according to the wavelength is arranged so that the contrast difference of the light emitted from each phosphor is increased.

In addition, the phosphor inspection method of the plasma display panel according to the present invention comprises a light emitting step of emitting each phosphor by irradiating the panel with a plurality of phosphors applied to the ultraviolet rays, the light emitted from each phosphor in the light emitting step A filtering step of differentially transmitting light according to a wavelength, a receiving step of receiving the light transmitted in the filtering step and converting the light into an image signal, and reading the image signal converted in the receiving step so that the brightness difference is higher than that of a peripheral system. If so, it is determined that the coating state of the phosphor is determined to be defective.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a block diagram showing a phosphor inspection apparatus of the plasma display panel according to the present invention.

In the apparatus for inspecting a phosphor of a plasma display panel according to the present invention, as shown in FIG. 4, an address electrode 122, a lower dielectric layer 124, and a partition wall 126 are formed on a lower surface of the PDP 120, and the partition wall 126 is formed. ), Red, green, and blue phosphors 128R, 128G, and 128B are respectively applied, and UV lamps 140 are disposed on the upper side of the lower surface of the PDP 120 at predetermined intervals. Ultraviolet rays are irradiated so as to emit 128R (128G) 128B.

In addition, a camera 130 for capturing and converting the light emitted by the ultraviolet lamp 140 and converted into an image signal on the upper side of the lower surface of the PDP 120 is installed to be connected to the camera 130. The microcomputer 150 reads the video signal converted at 130 to determine whether the phosphor 128 is defective.

Here, the ultraviolet lamp 140 is a germicidal ultraviolet lamp 140 having a central wavelength of about 254 nm is generally used.

In addition, since a color camera includes color information together with contrast information, it is preferable to use a monochrome camera having a small amount of processing information for quickness of inspection.

Since the monochrome camera is configured to read the color of the object according to the light and dark degree, each of the phosphors 128R, 128G, and 128B generates a light and dark difference according to the color.

Therefore, each of the phosphors 128R includes a lens 132 of the camera 130 such that the difference in light contrast between the light emitted from the phosphors 128R, 128G, and 128B is converted into an image signal. A filter 135 in which the transmittance is differentially applied to the emission wavelength band for the (128G) 128B is mounted.                     

The phosphor 128 is applied in the order of the phosphor of dark color to the phosphor of light color, that is, in order of red, green, and blue phosphors 128R, 128G, 128B, and the filter 135. Corresponds to each of the phosphors 128R, 128G and 128B so that the transmittance is increased.

As described above, the brightness of the phosphor 128 applied in a lower order than the brightness of the phosphor 128 applied in a higher priority is increased, and the contrast between the light transmitted by the filter 135 is greater and the mixed color is increased. The bright color phosphor 128 is mixed with the dark color phosphor 128 at the time of generation, so that it is easy to distinguish when detecting.

5 is a graph showing the emission wavelength band of a general phosphor, Figure 6 is a graph showing the transmittance of the phosphor by the emission wavelength band of the filter according to the present invention, Figure 7 is an emission wavelength band of another filter according to the present invention 8 is a graph showing the transmittance of the respective phosphors. FIG. 8 is an image photographed by applying the filter according to the present invention. The blue phosphor 128 emits light in an area of approximately 400 to 500 nm, and the green phosphor 128 is approximately 480. The light emits in the region of ˜590 nm, and the red phosphor 128 emits light in the region of approximately 580 to 710 nm.

On the other hand, the light emitted from the green phosphor 128 and the light emitted from the blue phosphor 128 is almost no difference in contrast occurs when visual or automatic inspection is mistaken or the accuracy of the test is reduced, the green phosphor 128 ) To reduce the brightness so that it is clearly distinguishable from the surroundings.

That is, the filter 135 has a high transmittance for light in the 400-500 nm band, which is the emission band of the blue phosphor 128, and a transmittance for the light in the 480-590 nm band, which is the emission band of the green phosphor 128, It is configured to be lower than the light of the blue phosphor 128 band, the light and light difference is deepened in the image transmitted to the filter 135 and captured by the camera 130.

For example, as shown in FIG. 6, when the light of the blue phosphor 128 transmitted through the filter 135 is 100% transmitted, the light of the green phosphor 128 transmitted through the filter 135 is When only about 70% of the green phosphor 128 is mixed with the blue phosphor 128, the brightness of the green phosphor 128 is darker than that of the blue phosphor 128. .

Likewise, if any three phosphors 128 are used, as shown in FIG. 7, the filter is adapted to adjust the contrast for any two phosphors. That is, the filter has transmittances of T1, T2, and T3 for wavelengths having a center wavelength of W1, W2, and W3, respectively, where T3 transmittance is 100%, T1 transmittance is less than 100% transmittance. The T2 transmittance is less than the T1 transmittance, and the difference in transmittance is preferably such that the ratio difference is large so that the contrast difference can be clearly distinguished.

For example, by using a filter in which the transmittance of T1 is set to 70% and the transmittance of T2 is set to about 40%, the difference in brightness for each wavelength becomes clear, and it is easy to make a defect such as mixing or blind spots for three phosphors. Can be determined or detected.

Looking at the operation of the present invention configured as described above are as follows.                     

First, when ultraviolet rays are irradiated using an ultraviolet lamp 140 on a PDP lower plate sequentially coated with red, green, and blue phosphors 128R, 128G, and 128B, each phosphor 128 reacts with ultraviolet rays. It is excited and emits light of different wavelengths.

As described above, the light emitted from each phosphor 128 is passed through the filter 135, and the transmittance is differentially applied according to each wavelength.

In addition, light passing through the filter 135 and having a difference in contrast due to a difference in contrast is captured by the monochrome camera 130 and converted into an image signal.

The light converted into the image signal as described above is read by the microcomputer 150. At this time, when the brightness difference is generated compared to the peripheral system, it can be seen that the fluorescent substance 128 has mixed color.

As described above, the apparatus and method for inspecting a phosphor of a plasma display panel according to the present invention have been described with reference to the illustrated drawings. However, the present invention is not limited by the embodiments and drawings disclosed herein and is within the technical scope of the present invention. Of course, various modifications, including materials, can be made by those skilled in the art.

Therefore, the fluorescent substance inspection apparatus and method of the plasma display panel according to the present invention configured as described above is to transmit each light differentially according to the wavelength so that the contrast difference of the light emitted from each phosphor between the phosphor and the camera increases. The filter is arranged to inspect the light emitted from each phosphor, so that defects such as color mixing and blind spots of the phosphor can be inspected quickly and accurately, and commercial UV lamps can be used to reduce production and maintenance costs. This reduces the processing data and enables high speed inspection.

Claims (8)

An ultraviolet lamp for irradiating light for emitting the plurality of phosphors to a lower plate of the plasma display panel to which the plurality of phosphors are applied in order of increasing brightness; A filter for increasing the lightness difference of the plurality of phosphors by increasing the transmittance in order of light from the phosphors having low brightness among the light generated from the plurality of phosphors; A single black and white camera for converting the color of the light transmitted through the one filter into a black and white video signal; And A microcomputer for reading the video signal converted by the single black and white camera, And the microcomputer reads the phosphor having a difference in brightness compared to the surroundings due to the black and white contrast of the image signal as a poor color mixture. delete Irradiating ultraviolet rays to the lower plate of the plasma display panel to which the plurality of phosphors are applied in order of increasing brightness; The light emitted from each of the plurality of phosphors by the irradiation of ultraviolet rays is transmitted to one filter whose transmittance increases from the light of the low-brightness phosphor to the light of the high-brightness phosphor, and according to the wavelength Filtering to increase the brightness difference between the phosphors; Converting a color of light generated by the plurality of phosphors passing through the one filter into a black and white video signal by a single black and white camera; And Determining that the phosphor having a difference in brightness due to black and white contrast of the black and white image signal is mixed color defect; Phosphor inspection method of the plasma display panel comprising a. delete delete delete delete delete

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