KR101823002B1 - Apparatus and method for testing of organic light-emitting display panel - Google Patents

Abstract

In the present invention, when a line defect is detected in a TFT array substrate including two or more pixels including a transistor supplying an electric current to the organic light emitting diode (OLED) and the organic light emitting diode (OLED), a defect position The method comprising the steps of: applying a signal for obtaining thermal image information to the TFT array substrate for the purpose of detecting and repairing the thermal image; obtaining thermal image information of the TFT array substrate using the thermal imaging camera; And acquiring information of the location.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light emitting diode (OLED)

The present invention relates to an inspection method and an inspection apparatus for an organic light emitting diode (OLED) display apparatus, and more particularly, to an inspection method and an inspection apparatus for detecting a defect in a TFT array substrate of an organic light emitting diode display apparatus.

In general, a flat panel display device such as an LCD (Liquid Crystal Display), a PDP (Plasma Display Panel), and an OLED (Organic Light Emitting Diode) is a device that receives electric energy and emits light. Unlike a conventional analog type display device such as a CRT, these display devices input digital image signals to signal lines and are turned on or off for each pixel by a liquid crystal, a plasma, an organic electroluminescent material or the like by a digital image signal, Is displayed.

In particular, an organic light emitting diode (OLED) display device is a display device for electrically exciting a fluorescent organic compound to emit light. The display device includes a plurality of N × M organic light emitting cells arranged in a matrix, consist of.

Such an organic light emitting cell has a diode characteristic and is also called an organic light emitting diode (OLED), and has a structure of an anode (ITO), an organic thin film, and a cathode electrode layer (metal). The organic thin film has a multilayer structure including an emitting layer (EML), an electron transport layer (ETL), and a hole transport layer (HTL) in order to improve the luminous efficiency by improving the balance of electrons and holes. And further includes a separate electron injecting layer (EIL) and a hole injecting layer (HIL). These organic light emitting cells are arranged in the form of N × M matrices to form an organic light emitting diode (OLED) display panel.

Although the passive type and the active type exist in the driving method of the organic light emitting diode (OLED), the active type is suitable in terms of material, lifetime and crosstalk in order to realize a large screen and a high definition display. In the active type, a thin film transistor is connected to each ITO (indium tin oxide) pixel electrode and driven according to a voltage maintained by a capacitance of the capacitor connected to the thin film transistor. Therefore, the active type display panel includes at least one thin film transistor and a capacitor in the pixel.

Such a display panel can be assembled up to a module, and full inspection can be made. However, if the inspection is performed after assembling the module, there arises a problem that the waste cost is increased when defective products are generated. Particularly, in an active type organic light emitting diode (OLED) display device, a plurality of elements are formed in a pixel, and there is a high possibility that a defective product occurs due to a large variation in an internal element caused by a poly-silicon process .

Accordingly, there is a need for a method of inspecting the defects of the TFT array substrate so that defects of the elements of the pixel circuit can be detected before the organic light emitting diode (OLED) display device is assembled to the module.

As a method of inspecting the TFT array substrate of the organic light emitting diode (OLED) display device, there is a method of charging a constant amount of charge to the capacitors of individual pixels on the TFT array substrate, checking the current value output from each pixel, Can be used. However, even in this method, if the data line is short-circuited and a defect occurs, the current values output from the capacitors of the pixels connected to the data line all have the same value, Can not be detected. Therefore, there is a problem in that it is impossible to detect the position where the defect occurs even though the defect is repairable.

Various embodiments of the present invention provide an inspection method and an inspection apparatus capable of detecting a position causing a defect even when a line defect occurs in a TFT array substrate of an organic light emitting diode (OLED) display apparatus .

A method of inspecting an organic light emitting diode (OLED) display device according to an embodiment of the present invention includes a step of forming an organic light emitting diode (OLED) A step of applying a signal for obtaining thermal image information to a TFT array substrate on which a line defect is detected when a line defect is detected on the array substrate, Acquiring thermal image information, and obtaining information of the defective position from the thermal image information.

An inspection apparatus of an organic light emitting diode (OLED) display apparatus according to another embodiment of the present invention includes an organic light emitting diode (OLED) and two or more pixels including a transistor for supplying current to the organic light emitting diode An inspection unit for moving a TFT array substrate on which a line defect is detected to an inspection position and applying an inspection signal when a line defect is detected on the TFT array substrate; A thermal image acquisition unit for acquiring thermal image information of the substrate, and a control unit for detecting information of a defective position that causes a line defect based on the thermal image information acquired from the thermal image acquisition unit.

According to an inspection method and an inspection apparatus for an organic light emitting diode (OLED) display device according to an embodiment of the present invention, a part of a data line of a TFT array substrate of an organic light emitting diode (OLED) ) Or a short occurs, even when a line defect occurs in the entire pixels connected to the data line, the point where the defect occurs can be detected. In addition, since defective points detected as described above can be repaired and used, it is possible to efficiently improve the yield problem caused by the increase in size of the organic light emitting diode (OLED) display device, while minimizing the time and cost.

1 is a circuit diagram of a single pixel of an organic light emitting diode (OLED) according to an embodiment of the present invention.
FIG. 2 is a flowchart showing an inspection step of an organic light emitting diode (OLED) display device according to an embodiment of the present invention.
Fig. 3 is a flowchart showing a signal application step for obtaining the thermal image information of Fig.
4 is a configuration diagram showing the configuration of an inspection apparatus of an organic light emitting diode (OLED) display device according to an embodiment of the present invention.
Figures 5 and 6 illustrate thermal image information obtained in accordance with one embodiment of the present invention.

The above objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. It is to be understood, however, that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities.

The detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, numerals (e.g., first, second, etc.) used in the description of the present invention are merely an identifier for distinguishing one component from another.

In addition, the suffix "module" and " part "for constituent elements used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role.

An organic light emitting diode (OLED) display device is more complicated and more complicated than a TFT LCD in which one pixel is composed of one transistor element and one capacitor element, and the number of electric and electronic elements such as transistors and capacitors constituting pixels. In addition, since the structure and operating method of the pixel circuit are different from each other, in order to smoothly operate these electronic devices, more excellent characteristics are required for the semiconductor thin film. However, in order to realize such characteristics, defects are more likely to occur due to factors in manufacturing technology Even if only one of the devices has an error, the possibility of failure is higher because the pixel itself does not function.

Therefore, in order to reduce the manufacturing cost of the organic light emitting diode (OLED) display device, it is more strongly required to perform a functional test in the step of forming the TFT array substrate and to send only good products to the next process. Particularly, by performing the electrical inspection process on the signal wiring and the pixel electrode, restoration can be performed on the substrate determined to be repairable, and disposal can be performed on defective substrates that can not be repaired.

Various embodiments of the present invention relate to an active matrix organic light emitting diode (OLED) display device, and more particularly to a method of inspecting a TFT array substrate before mounting an OLED of an organic light emitting diode (OLED) display device having an active matrix structure and ≪ / RTI >

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals refer to like elements throughout the specification.

In the exemplary embodiment of the present invention, each component, function block or means may be composed of one or more sub-components, and the electrical, electronic, and mechanical functions performed by the components may be electronic circuits, An integrated circuit, an ASIC (Application Specific Integrated Circuit), or the like, or may be implemented separately or two or more may be integrated into one.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the accompanying drawings.

1 shows a circuit diagram in a single pixel according to an example of an organic light emitting diode (OLED) display device.

1, a circuit for driving an organic light emitting diode (OLED) display device includes a plurality of first thin film transistors 101 and a plurality of second thin film transistors 103, a capacitor 102, For example, a power driver 105, a data driver 107, and a scan driver 106. In this case,

It will be apparent to those skilled in the art that the present invention is not limited to these structures, but may include a plurality of thin film transistors (TFTs), storage capacitors, and various wirings .

In the first thin film transistor 101 corresponding to the switching thin film transistor, a gate electrode is connected to the scan driver 106, and a source electrode is connected to the data driver 107. In the second thin film transistor 103 corresponding to the driving thin film transistor, a drain electrode is connected to the organic light emitting element 104, and a source electrode is connected to the power driver 105. The capacitor 102 is connected between the power source driver 105 and the gate electrode of the second thin film transistor 103.

The first thin film transistor 101 is driven by the scan signal applied to the gate electrode from the scan driver 106 and transmits the data signal applied from the data driver 107 to the second thin film transistor 103.

The second thin film transistor 103 determines the magnitude of the current flowing into the organic light emitting diode 104 due to the voltage difference between the gate electrode and the source electrode in accordance with the data signal transmitted through the first thin film transistor 101.

In addition, the capacitor 102 serves to store a data signal transmitted through the first thin film transistor 101 for one frame.

Here, the thin film transistors (TFT) are formed through a plurality of mask processes. One mask process may include a number of processes such as a thin film deposition (coating) process, a cleaning process, a photolithography process, an etching process, a strip process, an inspection process, and the like.

However, defects due to foreign substances may occur in each mask process. For example, when defects such as thin film transistor elements, pixel electrodes, and other wiring occur, a single pixel defect may occur. Further, in a mask process for forming a common line and an adjacent data line on a substrate, a defective pattern due to a foreign matter remains, resulting in a defect causing shorting of the data line and the common line. open or short occurs, the pixels connected to the defective data line may not operate in the entire line, so that a line defect may occur.

Single-pixel defects or line defects are usually caused by wiring defects, so if an open spot is found, the disconnected area is connected. If a short spot is found, the defective area is disconnected. It can be repaired.

Therefore, it is necessary to detect the position where the defect occurs in order to repair the TFT array substrate. A full contact array tester may be used as a method for checking whether or not the TFT array substrate of the organic light emitting diode (OLED) display device is defective.

A full contact array tester is a device capable of charging a certain amount of charge of a capacitor of an individual pixel on a TFT array substrate and checking whether the pixel is defective by checking the current value outputted from each pixel.

In the case of inspecting a TFT array substrate by a full contact array tester, if a single pixel defect occurs, the current value is not normally output in the capacitor of the pixel where the defect occurs, so that the pixel is determined as defective can do.

In addition, in the case where a line defect occurs, for example, when a line defect occurs due to the open of the data line, no current flows in the capacitor of the pixel after the open point, By detecting the start pixel, the data line point connected to the pixel can be detected as the open defect occurrence position, and this point can be repaired.

However, when the data line is short and a line defect occurs, the currents output from the capacitors of the pixels connected to the data line all have the same value. Therefore, the method using the full contact array tester can not detect the position of the shorted pixel when the data line is short-circuited.

That is, in view of the trend that a larger display area is required, even in the case of a TFT array substrate in which a line defect due to a short of a data line occurs, it is necessary to detect and repair the defective position, With a full contact array tester, it is impossible to detect a TFT array substrate in which a line defect occurs due to such a short circuit.

However, according to various embodiments of the present invention, even when a line defect due to a short of a data line occurs, a defect image is detected by measuring a thermal image of a pixel to which a current is applied through a thermal camera .

2 is a flowchart showing a method of inspecting an organic light emitting diode (OLED) display TFT array substrate, according to an embodiment of the present invention.

Referring to FIG. 2, an inspection method of an organic light emitting diode (OLED) display device TFT array substrate according to an embodiment of the present invention is a method of inspecting TFT array substrate of an organic light emitting diode display device through an electric method, (Step S210). In step S210, At this time, as a method of electrically detecting the TFT array substrate of the organic light emitting diode display device, a full contact array tester may be used.

Next, in step S220, it is possible to determine whether to proceed with the subsequent inspection step from the inspection result of step S210. For example, if a line defect due to a single pixel defect or open in the TFT array substrate is detected in step S210, it can be transferred to a repairing step. In addition, in the case where a single pixel defect or line defect is not detected on the TFT array substrate and it is determined that the product is good, the inspection step can be terminated by transferring the TFT array substrate to the next process step. However, in the case where a failure that can not detect a defect occurrence point is detected through a full contact array tester such as a line defect due to a short, a failure occurrence point of the TFT array substrate is detected Step S230 may be performed.

In step S230, an inspection signal for obtaining thermal image information may be input to the TFT array substrate of the organic light emitting diode display. Various inspection signals can be used to acquire thermal image information. FIG. 3 shows an example of a method of inputting inspection signals to acquire thermal image information.

3 is a flowchart showing an example of a concrete operation of the signal application step S230 for obtaining the thermal image information of Fig.

3, an inspection method according to an exemplary embodiment of the present invention includes moving a TFT array substrate of an organic light emitting diode display device that has failed to detect a defective position of a defect to an inspection position for obtaining thermal image information . ≪ / RTI > (S310) At this time, a robot arm capable of loading the raw TFT array substrate laminated on the cassette to the inspection position can be used.

In order to accurately apply an inspection signal to the terminal pad at the data line point corresponding to the line defective position of the TFT array substrate, the TFT array substrate is aligned at the inspection position (S320), and a probe pin To a test pad position corresponding to a pixel section to be inspected. (S330) At this time, the position of the test pad to which the probe pin is connected may be the position where the drive IC is mounted after the process of mounting the OLED.

Next, an electrical inspection signal may be applied (S340) to a corresponding data line of the TFT array substrate via a probe pin. The inspection signal applied here may be a current, and in particular, the inspection signal is preferably applied with a constant current to prevent damage to the TFT.

The inspection signal must be applied within a range that can heat the pixel to such an extent that the TFT can be accurately measured without damaging it. Therefore, the thermal image information can be obtained in such a manner that the voltage is gradually increased to such an extent that the defective position can be identified (S350) while monitoring the thermal image information after setting the appropriate constant current value and applying the signal. Can be limited within the range of the maximum voltage at which the TFT is not damaged.

For example, the images of FIGS. 5 and 6 corresponding to the thermal image information obtained according to an embodiment of the present invention are acquired by applying an inspection signal with a constant current of 5 mA and a maximum voltage of 30 V. FIG. The current value and the voltage value of the inspection signal can be appropriately adjusted according to the configuration and type of the organic light emitting diode (OLED) display device to be inspected.

On the other hand, after the signal for obtaining the thermal image information is inputted through the step S230, the thermal image information of the TFT array substrate to be inspected to be inspected can be obtained (S240) by using the thermal camera. The infrared camera may be an infrared ray detector that detects infrared rays emitted from an object to be measured and outputs a temperature detection signal corresponding thereto.

In step S240, it may further include a step of horizontally transporting the thermal imager to align the thermal imager with the measurement position of the spot where the thermal imagerial information is to be acquired.

Here, the thermal image information obtained in step S240 may be extracted as image information or a relative temperature value according to each pixel coordinate.

Next, the step of acquiring the information of the defective position through the obtained thermal image information (S250) may be included. FIGS. 5 and 6 illustrate thermal image information obtained according to an embodiment of the present invention. Referring to FIGS. 5 and 6, step S250 of acquiring information of a defective position will be described.

When the inspection signal is applied to the TFT array substrate for obtaining the thermal image information, the resistance is greater at the point where the pixel where the short occurs, so that the heat generation amount may be relatively high. Therefore, when a thermal image of the TFT array substrate is obtained in such a state, points that are displayed darkly or in a red-based color on the obtained image can be identified. If the image is displayed dark or red in the thermal image, it may mean that the point has a higher calorific value than other points.

Thus, by confirming the thermal image information as described above, it is possible to detect a point at which a line defect occurs due to a point having a high calorific value, that is, a short.

The step of acquiring the information of the defective position based on the thermal image information may be a step of acquiring the information of the defective position by observing the thermal image directly by the user according to various embodiments of the present invention, It is possible to acquire, as information of the defective position, a point at which the change of the deterioration image occurs most greatly by extracting and calculating the thermal image information according to the relative temperature value. In particular, the information of the defective position can be obtained in the form of pixel coordinate values.

On the other hand, in the step of acquiring the information of the defective position based on the thermal image information, a method of acquiring the information of the defective position is applied differently according to the degree of resistance difference between the point where the defect occurs due to the short and the point adjacent thereto .

When a large resistance difference occurs between the defective point and the adjacent point due to a short as shown in Fig. 5, the difference in calorific value between the defective point and the adjacent point is distinct, Can be obtained. For example, as shown in FIG. 5, when compared with neighboring pixels, it can be confirmed that a short has occurred at this point since it is reddish only at a point 510, and the coordinates of the pixel corresponding to 510 Can be acquired as information.

However, in the case where the difference in resistance between the defective point and the adjacent point due to the short is not relatively large and the difference in the calorific value is not large when the pixel at the defective point is compared with the adjacent pixels, The defective position can be detected by observing the path through which the current flows. For example, referring to FIG. 6, in contrast to the 510 point in FIG. 5, the 610 point has a relatively large thermal image chromaticity difference as compared with the adjacent pixel points, but the peripheral points and the chromaticity are distinguished from each other along the 620 line We can see that the 620 line is disconnected after showing the biggest difference at 610 point. As a result, a current flows along the path of 620 to generate a pixel, and it is possible to predict that a current is leaked from a point 610 to another point due to a short defect occurring at a point 610. Thus, .

According to an embodiment of the present invention, the obtained defective position information may further be transmitted to equipment of a repair process step to be performed later, and accordingly, a point where a defect occurs in the TFT array substrate where a line defect occurs, can do.

FIG. 4 is a view illustrating a configuration of an inspection apparatus for an organic light emitting diode display TFT array substrate according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 4, an inspection apparatus for a TFT array substrate of an organic light emitting diode display device according to an embodiment of the present invention detects a defect occurrence point using a thermal image of an energized TFT array substrate. A thermal image acquisition unit 20, and a control unit 30.

The inspection section 10 performs inspection for obtaining thermal image information of the TFT array substrate of the organic light emitting diode display device and may include an array supporting section 11 and an inspection signal applying section 12.

The array supporting portion 11 can support the TFT array substrate at the inspection position for applying the inspection signal and obtaining the thermal image information in the process of acquiring the thermal image information of the TFT array substrate of the organic light emitting diode display.

The inspection signal applying unit 12 can apply a driving signal for inspection from the probe pin to the TFT array substrate. According to an embodiment of the present invention, the applied inspection signal may be a current, and the inspection signal is preferably applied as a constant current in order to prevent damage to the thin film transistor (TFT).

The thermal image acquisition section 20 performs processing for acquiring thermal image information of the TFT array substrate of the organic light emitting diode display device, and in one embodiment, a thermal imaging camera can be used. An infrared camera is a device that collects radiation energy emitted from itself even if there is no supply of light from the outside, and changes it into an infrared image that can be seen by the eye. Such an infrared camera may be an infrared ray detector that detects infrared rays emitted from an object to be measured and outputs a temperature detection signal corresponding thereto.

On the other hand, the control unit 30 can control the inspection unit 10 and the thermal image acquisition unit 20 in general to obtain thermal image information.

The controller 30 can adjust the position of the probe pin by moving a probe pin of the inspection signal applying unit 12 while the TFT array substrate is positioned on the array supporting unit 11, It is possible to selectively apply an inspection signal through a probe pin having an arrangement corresponding to the arrangement of the terminal pads of the substrate among the probe pins of the substrate.

When the inspection signal is applied to the TFT array substrate by the inspection signal applying unit 12, the control unit 30 analyzes the thermal image distribution of the TFT array substrate from the thermal image information acquired by the thermal image acquisition unit 20 So that the defective position can be detected. For example, the defective position can be detected based on the result of comparing the chromaticity difference between adjacent pixels from the acquired image.

On the other hand, the information of the defective position obtained by the control unit 30 can be transmitted to the repair processing equipment of the TFT array substrate by the communication unit.

The TFT array substrate to be inspected of the present invention forms a plurality of pixel regions. The inspection apparatus of the present invention is characterized by comprising: a non-contact opening and short inspection of panels for each fabrication step; a non-contact opening and short inspection of TFT panels; ), Non-contact type open and short tests of electric circuits, and non-contact type open and short tests of other general electric circuits.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art that such changes or modifications are within the scope of the appended claims.

10: Inspection section 20:
30:
11: Array supporting part 12: Inspection signal applying part

Claims (9)

A method of inspecting an organic light emitting diode (OLED) display device,
In a TFT array substrate including two or more pixels including an organic light emitting diode (OLED) and a transistor for supplying current to the organic light emitting diode (OLED), when a line defect is detected,
Applying a signal for acquiring thermal image information to the TFT array substrate on which the line defect is detected;
Obtaining thermal image information of the TFT array substrate using an infrared camera; And
And acquiring information of a defective position from the acquired thermal image information. The method according to claim 1,
The step of applying a signal for obtaining thermal image information to the TFT array substrate on which the line defect is detected includes:
A probe pin is connected to a terminal pad corresponding to a data line of the TFT array substrate on which the line defect is detected,
Wherein a signal for inspection is applied to the terminal pad of the TFT array substrate through the probe pin connected thereto. The method according to claim 1,
Wherein the obtained information of the defective position is acquired in the form of pixel coordinate values of the defective position and transmitted to the repair processing equipment. 3. The method of claim 2,
Wherein the inspection signal applied to the terminal pad of the TFT array substrate through the connected probe pin is a constant current. An apparatus for testing an organic light emitting diode (OLED) display device,
When a line defect is detected in a TFT array substrate including two or more pixels including an organic light emitting diode (OLED) and a transistor for supplying a current to the organic light emitting diode (OLED)
An inspection unit for moving the TFT array substrate on which the line defect is detected to an inspection position and applying an inspection signal;
A thermal image acquisition unit for acquiring thermal image information of the TFT array substrate when the inspection signal is applied; And
And a control unit for detecting information of a defective position which causes a line defect based on the thermal image information acquired from the thermal image acquisition unit. 6. The method of claim 5,
Wherein,
Wherein information of a defect point is detected from the obtained thermal image information in the form of a pixel coordinate value of a defective position. 6. The method of claim 5,
Further comprising a communication unit,
Wherein the communication unit transmits information of the detected defective position to the repair process equipment. 6. The method of claim 5,
Wherein the inspection signal applied by the inspection unit is a constant current. ≪ RTI ID = 0.0 > 11. < / RTI > 6. The method of claim 5,
Wherein an inspection signal applied by the inspection unit is adjusted in size by voltage of the inspection signal by the control unit.

Images