TWI771105B - Detection method and circuit of OLED display panel - Google Patents

Abstract

The invention mainly discloses a detection method, which is used for defect detection of an OLED display panel. When applying the detection method of the present invention, a capacitor is first coupled to a driving voltage input terminal and a ground terminal of the OLED sub-pixel respectively, and then a detection unit is coupled between the first terminal and the driving voltage input terminal . Then, the pixel circuit unit is controlled to drive the OLED sub-pixel to emit light, and a detection unit is used to receive a detection signal. Finally, the detection signal is analyzed to determine whether the pixel circuit unit and/or the OLED sub-pixel is defective, so that the researcher can clarify the improvement direction of the defective pixel.

Description

Detection method and circuit of OLED display panel

The present invention relates to the technical field of OLED display panels, in particular to a detection method for OLED display panels.

It is known that a flat panel display includes a non-self-emissive flat panel display and a self-emissive flat panel display, wherein a liquid crystal display is a non-self-emissive flat panel display that has been used for a long time, and an organic light-emitting diode (OLED) Displays and light-emitting diode (LED) displays are known as self-luminous flat panel displays. FIG. 1 shows a block diagram of a conventional OLED display. As shown in FIG. 1, the structure of the OLED display 1a mainly includes: an OLED display panel 11a, a gate (column) driving unit 12a, a source (row) driving unit 13a, a display controller 14a, and a voltage Conversion unit 15a. The OLED display panel 11a includes M×N OLED sub-pixels 111a, M×N pixel circuit units 112a, M scan driving lines (gate lines) 11Ga, and N data driving lines (source lines) 11Sa . In more detail, each pixel circuit unit 112a is coupled to an electrical terminal of an OLED sub-pixel 111a, and is also coupled to a first driving voltage V _DD provided by the voltage conversion unit 15a. Moreover, the other electrical terminal of each OLED sub-pixel 111a is coupled to a second driving voltage V _SS provided by the voltage converting unit 15a, and the second driving voltage V _SS is usually a ground voltage.

Engineers who are familiar with the design and manufacture of OLED displays should know that the manufacture of the OLED display panel 11a can only be completed by cooperation between a circuit IC manufacturer (eg SMIC or TSMC) and a panel manufacturer (eg BOE or AUO). The circuit IC manufacturer is responsible for completing the manufacture of M×N pixel circuit units 112a of the OLED display panel 11a, and the panel manufacturer is responsible for completing the manufacture of M×N OLED sub-pixels 111a. It should be noted that, due to mass production, the mass-produced OLED display panel 11a inevitably includes defective pixels, and these defective pixels become bright spots or dark spots of the OLED display panel 11a. Of course, the existing testing method can detect defective pixels included in each OLED display panel 11a. However, the existing test methods cannot be judged based on the test results, resulting in defects. The main source of the trapped pixel is the pixel circuit unit 112a or the OLED sub-pixel 111a itself. That is, the existing testing method cannot determine whether the cause of the defective pixel comes from the process error of the circuit IC manufacturer or the process error of the panel manufacturer, so the R&D personnel cannot clarify the improvement direction of the defective pixel.

It can be seen from the above description that there is an urgent need in the art for a detection method for an OLED display panel.

The main purpose of the present invention is to provide an OLED display panel detection method, which is used for defect detection of an OLED display panel including M×N OLED sub-pixels and M×N pixel circuit units, so as to detect the OLED sub-pixels. The pixel and/or the pixel circuit unit has defects, so that developers can clarify the direction of improvement for defective pixels.

In order to achieve the above object, the present invention proposes an embodiment of the detection method for performing defect detection on an OLED display panel including M×N OLED sub-pixels and M×N pixel circuit units, and includes the following steps: A first terminal and a second terminal of a capacitor are respectively coupled to a driving voltage input terminal and a ground terminal of the OLED sub-pixel, and a detection terminal of a detection unit is coupled to the first terminal and the ground terminal. between the driving voltage input terminals; controlling the pixel circuit unit to drive the OLED sub-pixel connected to it to emit light; setting the detection terminal of the detection unit to a high impedance state, and using the detection terminal to receive a detection signal; and analyzing the detection signal to determine whether the pixel circuit unit and/or the OLED sub-pixel is defective.

In one embodiment, when the OLED sub-pixel and the pixel circuit unit work normally at the same time, the level of the detection signal detected by the detection unit is raised to a reference level after a reference time.

In one embodiment, when the pixel circuit unit works normally and the OLED sub-pixel has defects, the level of the detection signal detected by the detection unit is raised to the reference level after a first time. level, or a first voltage difference between it and the reference level.

In one embodiment, when the OLED sub-pixel works normally and the pixel circuit unit has defects, the level of the detection signal detected by the detection unit is raised to the reference level after a second period of time. level, or a second voltage difference between the level and the reference level.

In a feasible embodiment, the detection unit includes a comparator having a first input terminal coupled to the detection signal, a second input terminal coupled to a reference signal, and an output terminal, and the comparator is based on the detection signal and outputting a comparison signal with the reference signal, so as to determine that the pixel circuit unit and/or the OLED sub-pixel have defects according to the comparison signal.

In addition, the present invention also proposes an embodiment of the detection method for the OLED display panel, which is used to perform defect detection on an OLED display panel including M×N OLED sub-pixels and M×N pixel circuit units, and includes The steps are as follows: a first end and a second end of a capacitor are respectively coupled to a driving voltage input end and a ground end of the pixel circuit unit, and a detection end of a detection unit is coupled to the first between one end and the driving voltage input end; control the pixel circuit unit to drive the OLED sub-pixel connected to it to emit light; set the detection end of the detection unit to a high impedance state, and use the detection end to receive a detecting a signal; and analyzing the detection signal to determine whether the pixel circuit unit and/or the OLED sub-pixel is defective.

In one embodiment, when the OLED sub-pixel and the pixel circuit unit work normally at the same time, the level of the detection signal detected by the detection unit is raised to a reference level after a reference time.

In one embodiment, when the pixel circuit unit works normally and the OLED sub-pixel has defects, the level of the detection signal detected by the detection unit is raised to the reference level after a first time. level.

In one embodiment, when the OLED sub-pixel works normally and the pixel circuit unit has defects, the level of the detection signal detected by the detection unit is raised to the reference level after a second period of time. level.

In a feasible embodiment, the detection unit includes a comparator having a first input terminal coupled to the detection signal, a second input terminal coupled to a reference signal, and an output terminal, and the comparator is based on the detection signal and outputting a comparison signal with the reference signal, so as to determine that the pixel circuit unit and/or the OLED sub-pixel have defects according to the comparison signal.

Further, the present invention also provides a detection circuit, which has a capacitor and a detection unit for implementing the detection method of the present invention as described above, thereby completing the defect detection of an OLED display panel.

1a: OLED display

11a: OLED display panel

111a: OLED subpixel

112a: pixel circuit unit

11Ga: scan drive line

11Sa: Data Drive Line

12a: Gate drive unit

13a: source driver unit

14a: Display Controller

15a: Voltage conversion unit

11: OLED display panel

111: OLED sub-pixel

111p: The second drive voltage input terminal

112: Pixel circuit unit

112p: The first drive voltage input terminal

11G: scan drive line

11S: Data Drive Line

2: Detection circuit

20: Detection unit

201: Comparator

21: Capacitor

Step S1: make a first end and a second end of the capacitor be respectively coupled to the second driving voltage input end and a ground end of the OLED sub-pixel, and make a detection end of the detection unit coupled to the between the first terminal and the second driving voltage input terminal

Step S2: controlling the pixel circuit unit to drive the OLED sub-pixel connected to it to emit light

Step S3: Set the detection end of the detection unit to a high impedance state, and use the detection end to receive a detection signal

Step S4: Analyze the detection signal to determine that the pixel circuit unit and/or the OLED sub-pixel are defective

Step S1a: make a first end and a second end of the capacitor be respectively coupled to the first driving voltage input end and a ground end of the pixel circuit unit, and make a detection end of the detection unit coupled to the between the first terminal and the first driving voltage input terminal

Step S2a: controlling the pixel circuit unit to drive the OLED sub-pixel connected to it to emit light

Step S3a: Set the detection terminal of the detection unit to a high impedance state, and use the detection terminal to receive a detection signal

Step S4a: analyze the detection signal to determine that the pixel circuit unit and/or the OLED sub-pixel have defects

1 is a block diagram of a conventional OLED display; FIG. 2 is a block diagram of a detection circuit of the present invention and an OLED panel; FIG. 3 is a connection of a detection circuit, an OLED sub-pixel and a pixel circuit unit of the present invention Layout diagram; Figure 4 is a flow chart of a detection method of the present invention; Figure 5A is a connection layout diagram of a detection circuit, an OLED sub-pixel and a pixel circuit unit of the present invention; Figure 5B is a detection circuit of the present invention, an OLED The connection layout diagram of the sub-pixel and one pixel circuit unit; FIG. 6 is the internal circuit diagram of the detection circuit of the present invention; FIG. 7 is M×N OLED sub-pixels, M×N pixel circuit units and M detection circuits of the present invention. 8 is a connection layout diagram of a detection circuit, an OLED sub-pixel and a pixel circuit unit of the present invention; and FIG. 9 is a flowchart of a detection method of the present invention.

In order to enable your examiners to further understand the structure, features, objectives, and advantages of the present invention, drawings and detailed descriptions of preferred embodiments are attached as follows.

Please refer to FIG. 2 , which is a block diagram of a detection circuit and an OLED panel of the present invention. The present invention mainly discloses a detection circuit and method for performing defect detection on an OLED display panel 11, so as to detect that the OLED sub-pixel and/or the pixel circuit unit has defects, so that developers can clarify the defective pixels (defective pixels) direction of improvement. As shown in FIG. 2 , the OLED display panel 11 includes M×N OLED sub-pixels 111 , M×N pixel circuit units 112 , M scan driving lines (gate lines) 11G, and N data driving lines (source lines). polar line) 11S. To describe in more detail, each pixel circuit unit 112 is coupled to one OLED sub-pixel 111, and at the same time a first driving voltage input terminal thereof is coupled to a first driving voltage V _DD . In addition, each OLED sub-pixel 111 is coupled to a pixel circuit unit 112, and also has a second driving voltage input terminal coupled to a second driving voltage V _SS . The second driving voltage V _SS is usually a ground voltage.

FIG. 3 shows the connection layout diagram of the detection circuit, one OLED sub-pixel and one pixel circuit unit of the present invention, and FIG. 4 shows a flowchart of a detection method of the present invention. As shown in FIG. 3 , the detection circuit 2 of the present invention includes: a capacitor 21 and a detection unit 20 . And, as shown in FIG. 3 and FIG. 4 , the detection circuit method of the present invention first executes step S1 : a first end and a second end of the capacitor 21 are respectively coupled to the second end of the OLED sub-pixel 111 . The driving voltage input terminal 111p and a ground terminal, and a detection terminal of the detection unit 20 is coupled between the first terminal and the second driving voltage input terminal 111p.

As shown in FIG. 3 and FIG. 4 , the detection circuit method of the present invention then executes step S2 : controlling the pixel circuit unit 112 to drive the OLED sub-pixel 111 connected thereto to emit light. It should be understood that, in order to drive an OLED sub-pixel 111 to emit light, a scan voltage (or a selection voltage) V _SCAN , a display data voltage V _DATA , and a first driving voltage V _DD must be provided to the pixel circuit connected to the OLED sub-pixel 111 unit 112. At the same time, the second driving voltage V _SS must also be supplied to the OLED sub-pixel 111 . In order to detect whether the OLED sub-pixel 111 and/or the pixel circuit unit 112 has defects, as shown in FIG. 3 and FIG. 4 , the detection circuit method of the present invention then executes step S3 : setting the detection terminal of the detection unit 20 to It is in a high impedance state (ie, Hi-Z state), and the detection terminal is used to receive a detection signal. Finally, the detection circuit method of the present invention executes step S4 : analyzing the detection signal to determine whether the pixel circuit unit 112 and/or the OLED sub-pixel 111 is defective.

FIG. 5A shows the connection layout diagram of the detection circuit, one OLED sub-pixel and one pixel circuit unit of the present invention. It must be noted that in the case where the OLED sub-pixel 111 and the pixel circuit unit 112 work normally at the same time (ie, neither of them is defective), the pixel circuit unit 112 approximates a low-impedance line, and the OLED sub-pixel 112 The equivalent impedance of the pixel 111 (ie, the OLED element) is about 0.1 GΩ˜1 GΩ. In this case, as shown in FIG. 5A , the capacitor 21 is charged by the OLED current output by the second driving voltage input terminal 111p, so that the equivalent impedance of the OLED element and the capacitor 21 form an RC circuit. It should be understood that, as the charging time increases, the terminal voltage of the first terminal of the capacitor 21 will gradually increase and approach the DC level of the first driving voltage V _DD . Finally, when the charging time is equal to the RC time constant, the terminal voltage of the capacitor 21 will approach the first driving voltage V _DD , or be different from the first driving voltage V _DD by a specific voltage value. In other words, since a detection terminal of the detection unit 20 is coupled between the first terminal of the capacitor 21 and the second driving voltage input terminal 111p, the detection signal detected by the detection unit 20 is accurate The bit is raised to a reference level after a reference time (ie, the RC time constant). It can be seen from FIG. 5A that the reference level may be close to the DC level of the first driving voltage V _DD , or may differ from the DC level of the first driving voltage V _DD by a specific value, depending on the actual amount. The measured value is the final basis.

As shown in FIG. 5A , when the pixel circuit unit 112 works normally and the OLED sub-pixel 111 has defects, the equivalent impedance of the defective OLED sub-pixel 111 will be much smaller than that of the normal OLED sub-pixel 111 , etc. effective impedance. In this case, the level of the detection signal detected by the detection unit 20 is raised to the reference level after a first time, or has a first voltage difference with the reference level. It should be understood that the first time is the RC time constant between the equivalent impedance of the defective OLED sub-pixel 111 and the capacitor 21 .

5B and 5C both show the connection layout diagrams of the detection circuit, one OLED sub-pixel and one pixel circuit unit of the present invention. As shown in FIG. 5B , when the OLED sub-pixel 111 works normally and the pixel circuit unit 112 has defects, the level of the detection signal detected by the detection unit 20 is raised to the level after a second time. the reference level. In more detail, after the scan voltage V _SCAN , the display data voltage V _DATA , and the first driving voltage V _DD are provided to the pixel circuit unit 112 with defects, the pixel circuit unit 112 will form a short circuit or an open circuit. At this time, the OLED The equivalent impedance of the sub-pixel 111 will increase due to the circuit series effect with the pixel circuit unit 112 , resulting in an increase in the RC time constant between the equivalent impedance and the capacitor 21 . Therefore, in the case that the OLED sub-pixel 111 works normally and the pixel circuit unit 112 has defects, the level of the detection signal detected by the detection unit 20 must pass the second time (ie, the equivalent impedance and The RC time constant between the capacitors 21) is raised to the reference level, or there is a second voltage difference between the capacitors 21 and the reference level.

FIG. 6 shows an internal circuit diagram showing the detection circuit of the present invention. Engineers who are familiar with the design and manufacture of OLED displays should know that the manufacture of the OLED display panel 11 (as shown in FIG. 2 ) can only be achieved by cooperation between a circuit IC manufacturer (such as SMIC or TSMC) and a panel manufacturer (such as BOE or AUO). Finish. However, as shown in FIG. 6 , such a manufacturing process may cause interface misalignment between the pixel circuit unit 112 (manufactured by a circuit IC manufacturer) and the OLED sub-pixels 111 (manufactured by a panel manufacturer). In this case, the level of the detection signal detected by the detection unit 20 cannot be raised to the reference level until a third time has elapsed, or there is a third voltage difference between the detection signal and the reference level .

As shown in FIG. 6 , the detection unit 20 includes a comparator 201 having a first input terminal coupled to the detection signal, a second input terminal coupled to a reference signal, and an output terminal. In the case where there is an interface dislocation defect between the OLED sub-pixel 111 and the pixel circuit unit 112, the detection signal detected by the detection unit 20 will be due to the RC time constant between the equivalent impedance of the OLED sub-pixel 111 and the capacitor 21. There is a specific voltage difference between the reference level and the reference level, or the time required for raising to the reference level is different. According to this feature, the comparator 201 can be used to perform a comparison process on the detection signal and a reference signal having the reference level, so as to determine the pixel circuit unit 112 and/or the pixel circuit unit 112 and/or according to the comparison signal output by the comparator 201 The OLED sub-pixels 111 have defects. In other words, as long as the reference signal has a specified reference level by setting, the comparator 201 can be used to detect whether the OLED sub-pixel and/or the pixel circuit unit is defective.

FIG. 7 shows a connection layout diagram of M×N OLED sub-pixels, M×N pixel circuit units and M detection circuits of the present invention. In order to facilitate the acceleration of defect detection on an OLED display panel 11 including M×N OLED sub-pixels 111 and M×N pixel circuit units 112 , as shown in FIG. 7 , one of the N OLED sub-pixels 111 in the same column may be The second driving voltage input terminal 111p is simultaneously coupled to the capacitor 21 and the detection end of the detection unit is coupled to a common contact between the first end of the capacitor 21 and the N second driving voltage input ends 111p.

FIG. 8 shows the connection layout diagram of the detection circuit, one OLED sub-pixel and one pixel circuit unit of the present invention. In another possible embodiment, FIG. 8 shows that the detection circuit 2 of the present invention includes: a capacitor 21 and a detection unit 20 . On the other hand, FIG. 9 shows a flow chart of a detection method of the present invention. As shown in FIG. 8 and FIG. 9 , in another possible embodiment, the detection circuit method of the present invention first executes step S1a: a first end and a second end of the capacitor 21 are respectively coupled to the pixel circuit The first driving voltage input terminal 112p of the unit 112 and a ground terminal, and a detection terminal of the detection unit 20 is coupled between the first terminal and the first driving voltage input terminal 112p.

As shown in FIG. 8 and FIG. 9 , the detection circuit method of the present invention then executes step S2a: controlling the pixel circuit unit 112 to drive the OLED sub-pixel 111 connected thereto to emit light. In order to detect whether the OLED sub-pixel 111 and/or the pixel circuit unit 112 has defects, the detection circuit method of the present invention then executes step S3a: setting the detection terminal of the detection unit 20 to a high impedance state (ie, Hi-Z state), and use the detection terminal to receive a detection signal. Finally, the detection circuit method of the present invention executes step S4a: analyzing the detection signal to determine whether the pixel circuit unit 112 and/or the OLED sub-pixel 111 is defective.

In other words, when the pixel circuit unit 112 is controlled to drive the OLED sub-pixel 111 connected to it to emit light, the first driving voltage input terminal 112p (ie, the V _DD input terminal 112p) of the pixel circuit unit 112 can also be A detection signal is detected at the first terminal of the capacitor 21 coupled to the terminal), and then the detection signal is analyzed to determine whether the pixel circuit unit 112 and/or the OLED sub-pixel 111 is defective.

In this way, the above has completely and clearly described the detection method and circuit of an OLED display panel of the present invention; and, from the above, it can be known that the present invention has the following advantages:

(1) The present invention discloses a detection method and circuit for an OLED display panel, which are used for defect detection of an OLED display panel including M×N OLED sub-pixels and M×N pixel circuit units, so as to detect the OLED The sub-pixels and/or the pixel circuit unit have defects, so that developers can clarify the direction of improvement for defective pixels.

It must be emphasized that the above-mentioned one disclosed in this case is a preferred embodiment, and any partial changes or modifications that originate from the technical ideas of this case and are easily inferred by those who are familiar with the art are within the scope of the patent of this case. category of rights.

To sum up, regardless of the purpose, means and effect of this case, it shows that it is completely different from the conventional technology, and its first invention is suitable for practical use, and it does meet the patent requirements of the invention. Society is to pray for the best.

111: OLED sub-pixel

111p: The second drive voltage input terminal

112: Pixel circuit unit

112p: The first drive voltage input terminal

11G: scan drive line

11S: Data Drive Line

2: Detection circuit

20: Detection unit

21: Capacitor

Claims (10)

A detection method is used for defect detection of an OLED display panel including M×N OLED sub-pixels and M×N pixel circuit units, and includes the following steps: A first terminal and a second terminal of a capacitor are respectively coupled to a driving voltage input terminal and a ground terminal of the OLED sub-pixel, and a detection terminal of a detection unit is coupled to the first terminal and the ground terminal. between the driving voltage input terminals; controlling the pixel circuit unit to drive the OLED sub-pixel connected thereto to emit light; setting the detection terminal of the detection unit to a high impedance state, and using the detection terminal to receive a detection signal; and The detection signal is analyzed to determine whether the pixel circuit unit and/or the OLED sub-pixel is defective. The detection method according to claim 1, wherein when the OLED sub-pixel and the pixel circuit unit work normally at the same time, the level of the detection signal detected by the detection unit increases after a reference time. to a reference level. The detection method according to claim 2, wherein when the pixel circuit unit works normally and the OLED sub-pixel is defective, the level of the detection signal detected by the detection unit passes a first time Then, it is raised to the reference level, or there is a first voltage difference between the reference level and the reference level; wherein, in the case that the OLED sub-pixel works normally and the pixel circuit unit is defective, the detection unit The detected level of the detection signal is raised to the reference level after a second time, or has a second voltage difference with the reference level. The detection method according to claim 1, wherein the detection unit comprises a comparator having a first input terminal coupled to the detection signal, a second input terminal coupled to a reference signal, and an output terminal, the comparison The controller outputs a comparison signal according to the detection signal and the reference signal, so as to determine that the pixel circuit unit and/or the OLED sub-pixel has a defect according to the comparison signal. A detection circuit, which has a capacitor and a detection unit, is used to implement the detection method according to any one of claim 1 to claim 4, so as to complete defect detection of an OLED display panel. A detection method is used for defect detection of an OLED display panel including M×N OLED sub-pixels and M×N pixel circuit units, and includes the following steps: A first terminal and a second terminal of a capacitor are respectively coupled to a driving voltage input terminal and a ground terminal of the pixel circuit unit, and a detection terminal of a detection unit is coupled to the first terminal and the ground terminal. between the driving voltage input terminals; controlling the pixel circuit unit to drive the OLED sub-pixel connected thereto to emit light; setting the detection terminal of the detection unit to a high impedance state, and using the detection terminal to receive a detection signal; and The detection signal is analyzed to determine whether the pixel circuit unit and/or the OLED sub-pixel is defective. The detection method according to claim 6, wherein, when the OLED sub-pixel and the pixel circuit unit work normally at the same time, the level of the detection signal detected by the detection unit increases after a reference time. to a reference level. The detection method according to claim 7, wherein, when the pixel circuit unit works normally and the OLED sub-pixel is defective, the level of the detection signal detected by the detection unit passes a first time Then, it is raised to the reference level, or there is a first voltage difference between the reference level and the reference level; wherein, in the case that the OLED sub-pixel works normally and the pixel circuit unit is defective, the detection unit The detected level of the detection signal is raised to the reference level after a second time, or has a second voltage difference with the reference level. The detection method of claim 7, wherein the detection unit comprises a comparator having a first input terminal coupled to the detection signal, a second input terminal coupled to a reference signal, and an output terminal, the comparison The controller outputs a comparison signal according to the detection signal and the reference signal, so as to determine that the pixel circuit unit and/or the OLED sub-pixel has a defect according to the comparison signal. A detection circuit, which has a capacitor and a detection unit, is used to implement the detection method according to any one of claim 6 to claim 9, so as to complete defect detection of an OLED display panel.

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