阅读说明：本技术 测试方法 (Test method ) 是由 张舰 于 2021-09-06 设计创作，主要内容包括：本公开提供了一种测试方法,其中,根据本公开提供的测试方法,在对像素驱动单元中的第一薄膜晶体管的电学特性进行测试之前,切断所述第一薄膜晶体管的漏极与数据信号端之间的连接,能够消除第二薄膜晶体管、第三薄膜晶体管、数据信号端对第一薄膜晶体管的电学特性的测试的影响,以获取第一薄膜晶体管更加真实的电学特性。(According to the testing method provided by the disclosure, before the electrical characteristics of the first thin film transistor in the pixel driving unit are tested, the connection between the drain electrode of the first thin film transistor and the data signal terminal is cut off, so that the influence of the second thin film transistor, the third thin film transistor and the data signal terminal on the test of the electrical characteristics of the first thin film transistor can be eliminated, and the more real electrical characteristics of the first thin film transistor can be obtained.)

1. A test method for measuring an electrical characteristic of a first thin film transistor in a pixel driving unit, the test method comprising:

cutting off a physical electric connection path between the drain electrode of the first thin film transistor and a data signal end;

electrically connecting a first signal transmitting probe with a gate electrode of the first thin film transistor, electrically connecting a second signal transmitting probe with a source electrode of the first thin film transistor, and electrically connecting a signal receiving probe with a drain electrode of the first thin film transistor;

and respectively applying preset voltage to the first signal transmitting probe and the second signal transmitting probe to control the conduction of the source electrode and the drain electrode of the first thin film transistor, and measuring the electrical characteristics of the first thin film transistor according to the signal received by the signal receiving probe.

2. The method according to claim 1, wherein the pixel driving unit further comprises a second thin film transistor, a third thin film transistor, a main pixel electrode, an auxiliary pixel electrode, and a common electrode;

the source electrode of the second thin film transistor is electrically connected with the data signal end, and the drain electrode of the second thin film transistor is electrically connected with the main pixel electrode;

the source electrode of the third thin film transistor is electrically connected with the data signal end, and the drain electrode of the third thin film transistor is electrically connected with the auxiliary pixel electrode;

a source electrode of the first thin film transistor is electrically connected to the common electrode, a drain electrode of the first thin film transistor is electrically connected to the auxiliary pixel electrode, and when the source electrode and the drain electrode of the third thin film transistor are turned on, the drain electrode of the first thin film transistor is electrically connected to the data signal terminal.

3. The method according to claim 2, wherein when the second thin film transistor and the third thin film transistor are in an on state, the main pixel electrode and the auxiliary pixel electrode respectively obtain data driving signals through the second thin film transistor and the third thin film transistor to drive the corresponding pixel unit to display.

4. The method of claim 3, wherein the common electrode pulls down the potential of the auxiliary pixel electrode through the first thin film transistor to reduce the display brightness of the corresponding pixel unit when the first thin film transistor is in an on state.

5. The method according to claim 2, wherein the disconnecting the drain of the first thin film transistor from the data signal terminal comprises:

and cutting off the electrical connection between the drain electrode of the third thin film transistor and the auxiliary pixel electrode, so that the physical electrical connection path between the drain electrode of the first thin film transistor and the data signal terminal is cut off.

6. The method of claim 5, wherein a plurality of the pixel driving unit arrays are disposed on a substrate of an array substrate;

the array substrate comprises a first conducting layer, a first insulating layer, an active layer, a second conducting layer, a second insulating layer and a third conducting layer which are arranged on one side of the substrate in a laminated mode in a region corresponding to each pixel driving unit;

the first conducting layer is used for forming the grid electrodes of the first thin film transistor, the second thin film transistor and the third thin film transistor respectively;

the active layer is used for forming channels of the first thin film transistor, the second thin film transistor and the third thin film transistor with the first insulating layer and the first conducting layer respectively;

the third conductive layer is used for forming the main pixel electrode, the auxiliary pixel electrode and the common electrode respectively.

7. The method according to claim 6, wherein the second conductive layer is used to connect the source electrode of the second thin film transistor and the source electrode of the third thin film transistor to a data signal terminal, and connect the drain electrode of the second thin film transistor to the main pixel electrode through a first via hole and connect the drain electrode of the third thin film transistor to the auxiliary pixel electrode through a second via hole, respectively;

the second conductive layer is further configured to connect the source of the first thin film transistor to the common electrode through a third via hole, and connect the drain of the first thin film transistor to the auxiliary pixel electrode through a fourth via hole.

8. The method according to claim 7, wherein an electrical connection is formed between the auxiliary pixel electrode and the drain electrode of the third thin film transistor through the second conductive layer.

9. The method of claim 8, wherein the step of cutting off a physical electrical connection path between the drain electrode of the first thin film transistor and the data signal terminal comprises: and cutting off the second conductive layer for forming electric connection between the auxiliary pixel electrode and the drain electrode of the third thin film transistor in a laser cutting mode.

10. The method of any of claims 1 to 9, wherein the electrical characteristic comprises a leakage current of the first thin film transistor at the predetermined voltage.

Technical Field

The disclosure relates to the technical field of display, in particular to a test method.

Background

With the rapid development of internet technology and mobile communication technology, the world enters a brand new information age, the information content is increasingly rich and colorful, and as an important constituent part of the information industry, the display technology plays an important role in the development process of the information technology all the time. Nowadays, various Display devices are present in various fields of daily life and work, and as a second generation Display technology, which is already mature, in the process of the development of a new generation Display technology, Liquid Crystal Display (LCD) devices with better image quality and more stable and reliable performance are provided for users.

In the design process of a pixel driving circuit of an LCD product, the number and size of TFTs (Thin-Film transistors) are determined according to the performance requirements of the product, and for an LCD product with a wide viewing angle requirement, a main pixel (main-pixel) and a sub-pixel (sub-pixel) are usually designed and are respectively driven by the main-TFT and the sub-TFT in a corresponding pixel driving circuit unit, and meanwhile, a third TFT is also designed in the pixel driving circuit unit to pull down the voltage of the sub-pixel so as to enhance the luminance of the main-pixel.

The electrical characteristics of TFT are an important measure of the performance of TFT-LCD products. The electrical characteristics of the TFT can be understood by measuring the current-voltage curve (I-V curve) of the TFT. However, in the process of testing the electrical characteristics of the third tft, the drain of the third tft is connected to the data-line terminal (data-line) through the sub-pixel in the on state, and the measured current-voltage curve of the third tft cannot truly reflect the electrical characteristics of the third tft because the data-line terminal is in the floating state.

Disclosure of Invention

The present disclosure provides a testing method, which can eliminate the influence of other thin film transistors or signal terminals on the electrical characteristics of a thin film transistor to be tested when the testing method is used for testing the thin film transistor to be tested in a pixel driving unit.

In one aspect, the present disclosure provides a testing method for measuring an electrical characteristic of a first thin film transistor in a pixel driving unit, the testing method comprising:

cutting off a physical electric connection path between the drain electrode of the first thin film transistor and a data signal end;

electrically connecting a first signal transmitting probe with a gate electrode of the first thin film transistor, electrically connecting a second signal transmitting probe with a source electrode of the first thin film transistor, and electrically connecting a signal receiving probe with a drain electrode of the first thin film transistor;

and respectively applying preset voltage to the first signal transmitting probe and the second signal transmitting probe to control the conduction of the source electrode and the drain electrode of the first thin film transistor, and measuring the electrical characteristics of the first thin film transistor according to the signal received by the signal receiving probe.

In some embodiments of the present disclosure, the pixel driving unit further includes a second thin film transistor, a third thin film transistor, a main pixel electrode, an auxiliary pixel electrode, and a common electrode;

the source electrode of the second thin film transistor is electrically connected with the data signal end, and the drain electrode of the second thin film transistor is electrically connected with the main pixel electrode;

the source electrode of the third thin film transistor is electrically connected with the data signal end, and the drain electrode of the third thin film transistor is electrically connected with the auxiliary pixel electrode;

a source electrode of the first thin film transistor is electrically connected to the common electrode, a drain electrode of the first thin film transistor is electrically connected to the auxiliary pixel electrode, and when the source electrode and the drain electrode of the third thin film transistor are turned on, the drain electrode of the first thin film transistor is electrically connected to the data signal terminal.

In some embodiments of the present disclosure, when the second thin film transistor and the third thin film transistor are in a conducting state, the main pixel electrode and the auxiliary pixel electrode respectively obtain data driving signals through the second thin film transistor and the third thin film transistor to drive the corresponding pixel unit to display.

In some embodiments of the present disclosure, when the first thin film transistor is in an on state, the common electrode pulls down the potential of the auxiliary pixel electrode through the first thin film transistor to reduce the display brightness of the corresponding pixel unit.

In some embodiments of the present disclosure, the disconnecting the drain electrode of the first thin film transistor from the data signal terminal includes:

and cutting off the electrical connection between the drain electrode of the third thin film transistor and the auxiliary pixel electrode, so that the physical electrical connection path between the drain electrode of the first thin film transistor and the data signal terminal is cut off.

In some embodiments of the present disclosure, a plurality of the pixel driving unit arrays are disposed on a substrate of an array substrate;

the array substrate comprises a first conducting layer, a first insulating layer, an active layer, a second conducting layer, a second insulating layer and a third conducting layer which are arranged on one side of the substrate in a laminated mode in a region corresponding to each pixel driving unit;

the first conducting layer is used for forming the grid electrodes of the first thin film transistor, the second thin film transistor and the third thin film transistor respectively;

the active layer is used for forming channels of the first thin film transistor, the second thin film transistor and the third thin film transistor with the first insulating layer and the first conducting layer respectively;

the third conductive layer is used for forming the main pixel electrode, the auxiliary pixel electrode and the common electrode respectively.

In some embodiments of the present disclosure, the second conductive layer is configured to connect a source electrode of the second thin film transistor and a source electrode of the third thin film transistor to a data signal terminal, respectively, and connect a drain electrode of the second thin film transistor to the main pixel electrode through a first via hole, and connect a drain electrode of the third thin film transistor to the auxiliary pixel electrode through a second via hole;

the second conductive layer is further configured to connect the source of the first thin film transistor to the common electrode through a third via hole, and connect the drain of the first thin film transistor to the auxiliary pixel electrode through a fourth via hole.

In some embodiments of the present disclosure, an electrical connection is formed between the auxiliary pixel electrode and the drain electrode of the third thin film transistor through the second conductive layer.

In some embodiments of the present disclosure, the step of cutting off a physical electrical connection path between the drain electrode of the first thin film transistor and the data signal terminal includes: and cutting off the second conductive layer for forming electric connection between the auxiliary pixel electrode and the drain electrode of the third thin film transistor in a laser cutting mode.

In the method of any of the above embodiments, the electrical characteristic includes a leakage current of the first thin film transistor at the predetermined voltage.

Compared with the prior art, the testing method provided by the disclosure can eliminate the influence of other thin film transistors or signal terminals on the electrical characteristics of the thin film transistor to be tested in the pixel driving unit. Specifically, before testing the electrical characteristics of the first thin film transistor in the pixel driving unit provided by the present disclosure, the connection between the drain of the first thin film transistor and the data signal terminal is cut off, so that the influence of the second thin film transistor, the third thin film transistor and the data signal terminal on the test of the electrical characteristics of the first thin film transistor can be eliminated, and the more real electrical characteristics of the first thin film transistor can be obtained.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic plan structure diagram of a pixel driving unit according to an embodiment of the present disclosure.

Fig. 2 is a schematic diagram of another planar structure of a pixel driving unit according to an embodiment of the disclosure.

Fig. 3 is an equivalent circuit diagram corresponding to the pixel driving circuit in fig. 1 and 2.

Fig. 4 is a schematic diagram of a test result of a thin film transistor to be tested obtained by using the testing method of the present disclosure.

Fig. 5 is a schematic view of a partial film structure of an array substrate according to an embodiment of the present disclosure.

Detailed Description

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure. Furthermore, it should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, and are not intended to limit the present disclosure. In the present disclosure, unless otherwise specified, use of the directional terms "upper" and "lower" generally refer to upper and lower, and specifically to the orientation of the drawing figures in the drawings, in the actual use or operating condition of the device; while "inner" and "outer" are with respect to the outline of the device.

In one aspect, the present disclosure provides a testing method that is applicable at least to the pixel driving unit as shown in fig. 1 to 3.

In order to clearly describe the features of the test method provided by the present disclosure, the pixel driving structure shown in fig. 1 to 3 will be explained first. Fig. 1 and 2 are schematic plan views of the pixel driving unit, and fig. 3 is an equivalent circuit diagram corresponding to fig. 1 and 2.

As shown in fig. 1 to 3, a pixel driving unit according to an embodiment of the present disclosure includes: a first thin film transistor 101, a second thin film transistor 102, a third thin film transistor 103, a main pixel electrode, an auxiliary pixel electrode, a common electrode (share-bar), and the like. Here, the second thin film transistor 102 and the third thin film transistor 103 correspond to a main pixel electrode and an auxiliary pixel electrode, respectively.

Specifically, the gates of the first thin film transistor 101, the second thin film transistor 102, and the third thin film transistor 103 are connected to the same gate control terminal to receive the same gate control signal through a gate line (gate-line), wherein the gate control signal is used to control whether the thin film transistors are turned on, i.e., whether the sources and the drains of the thin film transistors are turned on.

Further, the source of the second thin film transistor 102 is connected to the data signal terminal to obtain a data driving signal through a data line (data-line), and the drain of the second thin film transistor 102 is connected to the main pixel electrode. The source of the third thin film transistor 103 is connected to the data signal terminal to obtain a data driving signal through a data line (data-line), and the drain of the third thin film transistor 103 is connected to the auxiliary pixel electrode.

Under the action of the gate control signal, when the second thin film transistor 102 and the third thin film transistor 103 are in an on state, the main pixel electrode and the auxiliary pixel electrode respectively obtain a data driving signal through the second thin film transistor 102 and the third thin film transistor 103, and then the pixel unit corresponding to the pixel driving unit is driven to display a picture corresponding to the received data driving signal.

Further, the source of the first thin film transistor 101 is connected to the common electrode, the drain of the first thin film transistor 101 is connected to the auxiliary pixel electrode, and under the action of the gate control signal, when the first thin film transistor 101 is in an on state, the common electrode can pull down the potential of the auxiliary pixel electrode to enhance the display brightness of the main pixel unit corresponding to the main pixel electrode.

It can be seen that the electrical characteristics of the thin film transistors in the pixel driving units affect the display quality of the display device. Therefore, it is necessary to test the electrical characteristics of the thin film transistors in the pixel driving unit, wherein the current-voltage curves (I-V curves) of the thin film transistors can reflect the electrical characteristics thereof. However, when measuring the I-V curve of the first tft 101, the second tft 102, and the third tft 103 are controlled by the same gate control signal and turned on simultaneously, the drain of the first tft 101 is substantially connected to the data signal terminal through the auxiliary pixel electrode and the source of the third tft 103, the sources of the second tft and the third tft 103 are connected to each other, and the data signal terminal is floating during the test process, so that the measured I-V curve cannot truly reflect the electrical characteristics of the first tft 101 under the influence of the second tft 102, the third tft 103, and the data signal terminal.

To solve this problem, the present disclosure provides a test method of disconnecting the drain of the first thin film transistor 101 from the data signal terminal before testing the electrical characteristics of the first thin film transistor 101.

Referring to fig. 2, according to the structure of the pixel driving unit provided by the embodiment of the present disclosure, a cut-off position is selected as a position along a straight line AB in fig. 1 to cut off the connection between the drain of the third thin film transistor 103 and the auxiliary pixel electrode.

In some embodiments of the present disclosure, the connection between the drain electrode of the third thin film transistor 103 and the auxiliary pixel electrode may be cut off in a laser (laser) manner.

Further, when measuring the I-V curve of the first thin film transistor 101, the first signal transmitting probe is connected to the gate electrode of the first thin film transistor 101, the second signal transmitting probe is connected to the common electrode, and the first signal receiving probe is connected to the auxiliary pixel electrode. Subsequently, preset voltages are applied to the first signal transmitting probe and the second signal transmitting probe respectively to control the conduction of the source and the drain of the first thin film transistor 101, and an I-V curve is generated according to the signal received by the first signal receiving probe, so as to obtain the electrical characteristics of the first thin film transistor 101.

In this way, in the process of testing the electrical characteristics of the first thin film transistor 101, since the first thin film transistor 101 is disconnected from the second thin film transistor 102, the third thin film transistor 103, or the data signal terminal, the obtained test result can truly reflect the electrical characteristics of the first thin film transistor 101.

Referring to fig. 4, fig. 4 is a voltage-current curve of the first thin film transistor 101 measured by the method provided by the present disclosure, and it can be seen that after the connection between the drain of the first thin film transistor 101 and the data signal terminal is cut OFF, the I _ OFF (leakage current) of the first thin film transistor 101 is significantly reduced.

The structure of the film layer of the pixel driving unit to which the testing method of the present disclosure is applied will now be described.

In some embodiments of the present disclosure, a plurality of the aforementioned pixel driving units are disposed on a substrate of an array substrate of a display device.

Referring to fig. 5, the array substrate includes a first conductive layer 502, a first insulating layer 503, an active layer 504, a second conductive layer 505, a second insulating layer 506, a third conductive layer 507, and the like stacked on one side of a substrate 501 at a position corresponding to each pixel driving unit.

In some embodiments of the present disclosure, the first conductive layer 502 is used to form a gate of a thin film transistor, the active layer 504 is used to form a channel of the thin film transistor with the first insulating layer 503 and the first conductive layer 502, respectively, and the third conductive layer 507 is used for the plurality of electrodes.

Referring to fig. 2, the second conductive layer 505 is further used for connecting the source of the second thin film transistor 102 and the source of the third thin film transistor 103 to the data signal terminal, respectively, so as to obtain the data driving signal through the data line. The second conductive layer 505 also serves to connect the drain electrode of the second thin film transistor 102 to the main pixel electrode through the first via hole, and to connect the drain electrode of the third thin film transistor 103 to the sub pixel electrode through the second via hole.

Further, the second conductive layer 505 is further configured to connect the source of the first thin film transistor 101 to the common electrode through a third via, and connect the drain of the first thin film transistor 101 to the auxiliary pixel electrode through a fourth via.

The first via hole, the second via hole, the third via hole, and the fourth via hole are all through holes and formed in the second insulating layer 506, so that when the third conductive layer 507 is prepared, the material of the third conductive layer 507 can directly contact the second conductive layer 505 through each via hole.

Therefore, before the electrical characteristics of the first thin film transistor 101 are tested using the test method provided by the present disclosure, the second conductive layer 505 for connecting the auxiliary pixel electrode and the drain electrode of the third thin film transistor 103 is cut off.

The test method, the array substrate and the display device provided by the embodiment of the disclosure are described in detail above, and specific examples are applied herein to explain the principle and the implementation of the disclosure, and the description of the embodiments is only used to help understand the method and the core idea of the disclosure; meanwhile, for those skilled in the art, according to the idea of the present disclosure, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present description should not be construed as a limitation to the present disclosure.