JP2009075044A - Film thickness defective inspection device for conductive polymer layer of organic el panel substrate, and method for inspecting film thickness defective using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film thickness defective inspection device for a conductive polymer layer of an organic EL panel substrate capable of efficiently inspecting a conductive polymer layer after the conductive polymer layer is formed, and a method for inspecting a film thickness defect using the same. <P>SOLUTION: This film thickness inspection device 100 for a conductive polymer layer of an organic EL panel substrate comprises a spectral reflection factor measuring means 10 for measuring beforehand a spectral reflection factor at least three levels of film thickness in an estimated range of film thickness of the conductive polymer layer, an image capturing means 20 having a band pass filter 22 capable of transmitting a waveform mostly inducing a difference in a reflection factor in accordance with a result obtained by the spectral reflection factor measuring means 10, an A/D conversion means 30 for converting captured analogue image data to digital image data, an image processing means 40 for processing the digital image data, a film thickness defect judgment processing means 50 for processing judgment of normality or fault of the film thickness, and a control means 60 for controlling each of the above means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a film thickness defect inspection apparatus and a film thickness defect inspection method for a conductive polymer layer of an organic EL panel substrate on which a conductive polymer layer is formed.

In the organic EL panel, variation in the film thickness of the hole transport layer and the light emitting layer is a major factor in uneven light emission. Since the light-emitting layer fluoresces when irradiated with excitation light, cells with abnormal film thickness can be identified by observing the brightness, but such a method cannot be used because the hole transport layer is a non-light-emitting material. . Since each cell must be measured with a film thickness measuring device and takes time, only a part of the panel can be measured. Therefore, there is a problem that the defective film thickness of the conductive polymer layer cannot be known unless the panel is finally completed and light is emitted.
For this reason, a detection apparatus and a film thickness difference detection method for detecting a film thickness difference between color filters with a simple apparatus and configuration have been proposed (see, for example, Patent Document 1).
JP 2006-184125 A

  The present invention has been devised in view of the above problems. In an organic EL panel composed of an anode, a hole transport layer, a light emitting layer / electron transport layer, and a cathode in this order, an ITO film is transported to the anode, and the hole transport is performed. When a conductive polymer layer such as PEDOT is used for the layer, the film thickness defect of the conductive polymer layer of the organic EL panel substrate is made possible to efficiently inspect the film thickness defect of the conductive polymer layer after the formation of the conductive polymer layer. An object of the present invention is to provide an inspection apparatus and a film thickness defect inspection method using the inspection apparatus.

  In order to achieve the above object in the present invention, first, in claim 1, at least three levels from the optical constant of the conductive polymer material to be used and the film thickness range of the conductive polymer layer assumed in the manufacturing process. Spectral reflectance measuring means 10 for measuring spectral reflectance at the film thickness in advance, and bandpass filter 22 that transmits a wavelength that most causes a difference in reflectance from the result obtained by the spectral reflectance measuring / fixing means 10 are provided. Imaging means 20, A / D conversion means 30 for converting the captured analog data image into a digital data image, image processing means 40 for processing the digital data image, and film thickness for determining whether the film thickness is normal or defective An apparatus for inspecting a film thickness defect of a conductive polymer layer of an organic EL panel substrate, comprising: a defect judgment processing means 50; and a control means 60 for controlling each means. It is intended.

  Moreover, in Claim 2, in the organic EL (electroluminescence) display panel comprised in order of the anode, the hole transport layer, the light emitting layer / electron transport layer, and the cathode, an ITO (indium tin oxide) film is formed on the anode. In the case of using a conductive polymer layer for the hole transport layer, a method for inspecting the film thickness defect of the conductive polymer layer performed after the formation of the conductive polymer layer, the optical constant of the conductive polymer material used and the manufacturing process Spectral reflectance at the minimum three levels of film thickness is calculated in advance from the assumed film thickness range of the conductive polymer layer, and the wavelength with the greatest difference in reflectance is selected from the obtained results. A conductive polymer for an organic EL panel substrate, characterized in that a difference in film thickness is imaged with a good contrast by mounting a bandpass filter that transmits light, and a cell having an abnormal film thickness is detected. It is obtained by the film thickness defect inspection method of the layers.

Furthermore, in Claim 3, the said conductive polymer layer is PEDOT, It is set as the film thickness defect inspection method of the conductive polymer layer of Claim 2 characterized by the above-mentioned.

  According to the present invention, in manufacturing an organic EL panel, it is possible to efficiently perform a film thickness defect inspection of a conductive polymer layer after forming a conductive polymer layer, which has been difficult in the past. The film thickness defect of the conductive polymer layer that did not exist can be found at an early stage, and defective organic EL panels can be reduced.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a schematic configuration diagram showing an example of a film thickness defect inspection apparatus for a conductive polymer layer of an organic EL panel substrate of the present invention.
The film thickness defect inspection apparatus 100 for the conductive polymer layer of the organic EL panel substrate of the present invention has a film thickness of at least three levels from the optical constant of the conductive polymer material and the film thickness range of the conductive polymer layer assumed in the manufacturing process. An imaging device including a spectral reflectance measuring unit 10 that measures spectral reflectance in advance in advance, and a bandpass filter 22 that transmits a wavelength that causes the difference in reflectance most from the result obtained by the spectral reflectance measuring / fixing unit 10 Means 20, A / D conversion means 30 for converting the captured analog data image into a digital data image, image processing means 40 for processing the digital data image, and film thickness defect determination for determining whether the film thickness is normal or defective It comprises a processing means 50 and a control means 60 that controls each means.

  In the spectral reflectance measuring means 10, the spectrophotometer preliminarily calculates the spectral reflectance at a film thickness of at least three levels from the optical constant of the conductive polymer material to be used and the film thickness range of the conductive polymer layer assumed in the manufacturing process. It is measured and used to select a bandpass filter when the imaging means 20 images the film thickness difference of the conductive polymer layer.

In the imaging means 20, an organic EL panel substrate 71 that is an object to be inspected is set on the substrate transport stage 61. Illumination light from the line illumination 23 passes through the band-pass filter 22, and transmits light in a wavelength region that allows imaging of the film thickness difference of the conductive polymer layer with good contrast. The light vertically enters the EL panel substrate 71.
The normal incident light is reflected on the surface of the conductive polymer layer and transmitted through the conductive polymer layer, causing interference between the light reflected at the interface with the ITO film surface and returning, and the film thickness of the conductive polymer layer. The intensity of reflection is generated at a wavelength corresponding to. This is imaged by an electro-optical detection means 21 typified by a line camera.

The A / D conversion means 30 converts the analog image obtained by the imaging means 20 into a digital image signal.
The image processing means 40 processes the A / D converted two-dimensional digital image over a two-dimensional scanning area and stores it in the image memory.

  The film thickness defect determination processing means 50 executes a program for extracting film thickness defects from the image stored in the image memory, and determines whether the film thickness of the conductive polymer layer is normal or defective. Of course, defect detection processing can also be performed by a hardware circuit other than the computer program.

  The processing procedure for the captured image is as follows. The image is projected in the X and Y directions to become one-dimensional data. Since the position of the cell can be recognized by scanning the one-dimensional data, each cell is surrounded by a predetermined rectangular size, binarized by a preset threshold value, and then the number of black pixels in the rectangle is totalized. A cell in which this value deviates from a predetermined normal range is determined as a film thickness defect of the conductive polymer layer.

  The control means 60 controls and controls the entire film defect inspection apparatus for the conductive polymer layer of the organic EL panel substrate at the same time as instructing and controlling each means.

Hereinafter, a method for inspecting a film thickness defect of a conductive polymer layer using a film thickness defect inspection apparatus for a conductive polymer layer of an organic EL panel substrate of the present invention will be described.
First, the layer structure of the organic EL panel will be described with reference to FIG. A glass substrate 111 has an ITO (indium tin oxide) film 121, and a hole transport layer 141 made of a conductive polymer layer is formed in a state where the partition wall 131 of each pixel is formed. In the subsequent steps, R, G, B light emitting layers 151, 161, 171 and a cathode layer 181 are formed and sealed to complete an organic EL panel.
Here, the conductive polymer layer is made of PEDOT.
In the present invention, the film thickness abnormality of the conductive polymer layer 141 is inspected in the state of the organic EL panel substrate (see FIG. 3) on which the hole transport layer 141 made of the conductive polymer layer is formed.

The optical constant of the conductive polymer layer made of PEDOT is shown in FIG. 4 (a), and the optical constant of the ITO film is shown in FIG. 4 (b). Even in the case of a multilayer film, the spectral reflectance can be calculated if the optical constant and the film thickness are given.
Using this numerical value, the normal incidence spectral reflectance is calculated when the film thickness of the ITO polymer film is 150 nm on the glass substrate and the film thickness of the conductive polymer layer made of PEDOT is changed to 40 nm, 50 nm, and 60 nm. 5 shows.
As can be seen from the graph, the reflectance difference due to the film thickness difference is large on the short wavelength side. Therefore, if the panel is imaged using a bandpass filter that transmits this wavelength range and cuts other wavelength ranges, the image is brighter if it is thinner than the standard film thickness of 50 nm, and darker if it is thicker. . Images can be captured with better contrast than when no bandpass filter is used.

  The three levels of film thickness that determine the wavelength range of the bandpass filter can be set from the ideal film thickness and the upper and lower limits of the film thickness in the actual manufacturing process. In this range, it is possible to efficiently inspect the change in film thickness of the conductive polymer layer by selecting a wavelength region having the largest reflectance difference.

  FIG. 6 shows a plot of the results measured with a stylus profilometer after the conductive polymer layer 141 made of PEDOT is formed between the partition walls 131 and 131. Here, the flat portion near the center between the partition walls contributes to the light emission, and the portion where the film thickness near the partition wall 131 is thick does not contribute to the light emission. Therefore, when determining the film thickness abnormality, the area of the flat portion at the center is important. An example in which the area of the flat portion at the center is different is shown in FIG. 7 as a cross-sectional view and a top view. Compared with the cell 51, the cell 52 has a larger flat portion at the center. Therefore, the captured image is binarized, the area of each cell is calculated, and compared with the area of the normal part, a result highly correlated with the light emission unevenness due to the film thickness abnormality can be obtained.

  According to the present invention, in manufacturing an organic EL panel, it is possible to efficiently perform a film thickness defect inspection of a conductive polymer layer after forming a conductive polymer layer, which has been difficult in the past. The film thickness defect of the conductive polymer layer that did not exist can be found at an early stage, and defective organic EL panels can be reduced.

It is a schematic block diagram which shows one Example of the film thickness defect inspection apparatus of the conductive polymer layer of the organic electroluminescent panel board | substrate of this invention. It is a schematic structure sectional view showing an example of an organic EL panel. It is a schematic cross section showing an example of an organic EL panel substrate. (A) is explanatory drawing which shows an example of the optical constant of a conductive polymer layer. (B) is explanatory drawing which shows an example of the optical constant of an ITO (indium tin oxide) film | membrane. An example of a normal incidence spectral reflectance curve when the film thickness of the conductive polymer layer is changed to 40 nm, 50 nm, and 60 nm is shown. An example of a result obtained by forming a conductive polymer layer made of PEDOT between the partition wall 131 and the partition wall 131 and then measuring with a stylus profilometer is shown. (A) is a schematic cross-sectional view and a schematic top view of the cell 51 in which the conductive polymer layer made of PEDOT formed between the partition walls 131 is determined to be defective. (B) is a schematic cross-sectional view and a schematic top view of the cell 52 in which the conductive polymer layer made of PEDOT formed between the partition walls 131 is determined to be normal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Spectral reflectance measuring means 20 ... Imaging means 21 ... Electro-optical detection means 22 ... Band pass filter 23 ... Line illumination 24 ... Beam splitter 30 ... A / D conversion means 40 ... Image Processing means 50 ... Film thickness defect judgment processing means 51, 52 ... Cell 60 ... Control means 61 ... Stage 71 ... Organic EL panel substrate 100 ... Film thickness defect inspection device 111 ... Glass substrate 121 ... ITO (Indium tin oxide) film 131 ... partition wall 141 ... conductive polymer layer 151 ... R light emitting layer 161 ... G light emitting layer 171 ... B light emitting layer 181 ... cathode layer

Claims (3)

  Spectral reflectance measurement means (10) for measuring in advance at least three levels of spectral reflectance from the optical constant of the conductive polymer material to be used and the film thickness range of the conductive polymer layer assumed in the manufacturing process; An imaging means (20) having a band-pass filter (22) that transmits a wavelength at which the difference in reflectance is the most from the result obtained by the spectral reflectance measurement and determination means (10), and an analog data image taken A / D conversion means (30) for converting into a digital data image, image processing means (40) for processing the digital data image, and film thickness defect judgment processing means (50) for judging whether the film thickness is normal or defective And a control means (60) for controlling each means, and a film thickness defect inspection apparatus for a conductive polymer layer of an organic EL panel substrate.   In an organic EL (electroluminescence) display panel composed of an anode, hole transport layer, light emitting layer / electron transport layer, and cathode in this order, an ITO (indium tin oxide) film is used as the anode, and a conductive polymer is used as the hole transport layer. When a layer is used, this is a method for inspecting defective film thickness of a conductive polymer layer performed after the formation of the conductive polymer layer, and includes an optical constant of a conductive polymer material to be used and a conductive polymer layer assumed in a manufacturing process. Spectral reflectance at the minimum three levels of film thickness is calculated in advance from the film thickness range, and the wavelength with the greatest difference in reflectance is selected from the obtained results, and a bandpass filter that transmits that wavelength is installed. A method for inspecting a film thickness defect of a conductive polymer layer of an organic EL panel substrate, wherein a difference in film thickness is imaged with good contrast to detect a cell having an abnormal film thickness.   The method for inspecting film thickness defects of a conductive polymer layer according to claim 2, wherein the conductive polymer layer is PEDOT.

Images