KR-20260064001-A - PIXEL CIRCUIT, AND DISPLAY PANEL AND DISPLAY DEVICE INCLUDING THE PIXEL CIRCUIT

Abstract

A pixel circuit, a display panel including the same, and a display device are disclosed. The pixel circuit is disposed in a non-display area and includes a plurality of driving transistors with different channel ratios and a plurality of selection transistors that select one or more of the driving transistors in response to different selection signals.

Inventors

• 백호선
• 민경율

Assignees

• 엘지디스플레이 주식회사

Dates

Publication Date

20260507

Application Date

20241031

Claims (20)

1. A plurality of driving transistors with different channel ratios, disposed in a non-display area; and A pixel circuit comprising a plurality of selection transistors that select one or more of the driving transistors in response to different selection signals.
2. In Article 1, A plurality of driving transistors with different channel ratios are connected to a repair line crossing the non-display area and the display area, and The above repair line is a pixel circuit connected to a light-emitting element of a repaired subpixel within the above display area.
3. In Article 2, A pixel circuit in which current generated from a selected driving transistor flows through the repair line and the driving voltage of the light-emitting element is applied to the light-emitting element.
4. In Article 2, During the slew time of the driving voltage charged to the light-emitting element, the driving voltage of the light-emitting element is output from two or more driving transistors, and A pixel circuit in which the driving voltage of the light-emitting element is output from a number of driving transistors smaller than the number of driving transistors during the settled time after the slew time.
5. In Article 2, A pixel circuit in which the number of driving transistors driving the light-emitting element increases as the distance between the driving transistors and the light-emitting element increases.
6. In Article 2, A pixel circuit in which a larger current is generated from the driving transistors driving the light-emitting element as the distance between the driving transistors and the light-emitting element increases.
7. In Article 2, A pixel circuit in which the channel ratio of the driving transistors driving the light-emitting element increases as the distance between the driving transistors and the light-emitting element increases.
8. In Article 2, The above selection transistors are, It includes a first selection transistor, a second selection transistor, and a third selection transistor, The above driving transistors are, It includes a first driving transistor, a second driving transistor, and a third driving transistor, The gate electrode of the first driving transistor, the gate electrode of the second driving transistor, and the gate electrode of the third driving transistor are connected to the first node, and The first selection transistor comprises a gate electrode to which a first selection signal is applied, a first electrode connected to a second node, and a second electrode connected to the first electrode of the first driving transistor. The second selection transistor comprises a gate electrode to which a second selection signal is applied, a first electrode connected to the second node, and a second electrode connected to the first electrode of the second driving transistor. The third selection transistor comprises a gate electrode to which a third selection signal is applied, a first electrode connected to the second node, and a second electrode connected to the first electrode of the third driving transistor. A pixel circuit in which the second electrode of the first driving transistor, the second electrode of the second driving transistor, and the second electrode of the third driving transistor are connected to a third node.
9. In Article 8, A pixel circuit further comprising a switch transistor that electrically connects the third node to the repair line in response to a gate signal.
10. In Article 8, A first switch transistor that electrically connects the first node to the third node in response to a first gate signal; and A pixel circuit further comprising a second switch transistor that electrically connects a dummy data line placed in the non-display area to the second node in response to a second gate signal.
11. In Article 10, A third switch transistor that supplies a pixel driving voltage to the second node in response to a fifth gate signal; A fourth switch transistor that electrically connects the third node to the repair line in response to the fifth gate signal; A fifth switch transistor that applies an initialization voltage to the first node in response to a fourth gate signal; A sixth switch transistor that applies an anode reset voltage to the repair line in response to a third gate signal; A seventh switch transistor that applies an on-bias voltage to the second node in response to the third gate signal; and It further includes a first constant voltage node to which the pixel driving voltage is applied, and a capacitor connected between the first node. A pixel circuit in which the anode electrode of the light-emitting element is connected to the repair line, and a pixel ground voltage lower than the pixel driving voltage is applied to the cathode electrode of the light-emitting element.
12. A display area where multiple subpixels are arranged; A non-display area where multiple dummy subpixels are placed; and It includes a plurality of repair lines connected to corresponding dummy subpixels across the above-mentioned display area and the above-mentioned non-display area, and The above display area includes at least one repaired subpixel, and The above-mentioned repaired subpixel is, It includes a light-emitting element and a driving transistor electrically isolated from the light-emitting element, At least one of the above dummy subpixels is connected to the light-emitting element of the repaired subpixel through the repair line, and The dummy subpixel connected to the above light-emitting element is, Multiple driving transistors with different channel ratios; and A display panel comprising a plurality of selection transistors that select one or more of the driving transistors in response to different selection signals.
13. In Article 12, A plurality of driving transistors with different channel ratios are connected to a repair line crossing the non-display area and the display area, and A display panel in which the above repair line is connected to a light-emitting element of a repaired subpixel within the above display area.
14. In Article 13, A display panel in which the channel ratio of the driving transistors driving the light-emitting element increases as the distance between the driving transistors and the light-emitting element increases.
15. In Article 13, The above selection transistors are, It includes a first selection transistor, a second selection transistor, and a third selection transistor, The above driving transistors are, It includes a first driving transistor, a second driving transistor, and a third driving transistor, The gate electrode of the first driving transistor, the gate electrode of the second driving transistor, and the gate electrode of the third driving transistor are connected to the first node, and The first selection transistor comprises a gate electrode to which a first selection signal is applied, a first electrode connected to a second node, and a second electrode connected to the first electrode of the first driving transistor. The second selection transistor comprises a gate electrode to which a second selection signal is applied, a first electrode connected to the second node, and a second electrode connected to the first electrode of the second driving transistor. The third selection transistor comprises a gate electrode to which a third selection signal is applied, a first electrode connected to the second node, and a second electrode connected to the first electrode of the third driving transistor. A display panel in which the second electrode of the first driving transistor, the second electrode of the second driving transistor, and the second electrode of the third driving transistor are connected to a third node.
16. In Article 15, A display panel further comprising a switch transistor that electrically connects the third node to the repair line in response to a gate signal.
17. In Article 15, A first switch transistor that electrically connects the first node to the third node in response to a first gate signal; and A display panel further comprising a second switch transistor that electrically connects a dummy data line placed in the non-display area to the second node in response to a second gate signal.
18. In Article 17, A third switch transistor that supplies a pixel driving voltage to the second node in response to a fifth gate signal; A fourth switch transistor that electrically connects the third node to the repair line in response to the fifth gate signal; A fifth switch transistor that applies an initialization voltage to the first node in response to a fourth gate signal; A sixth switch transistor that applies an anode reset voltage to the repair line in response to a third gate signal; A seventh switch transistor that applies an on-bias voltage to the second node in response to the third gate signal; and It further includes a first constant voltage node to which the pixel driving voltage is applied, and a capacitor connected between the first node. A display panel in which the anode electrode of the light-emitting element is connected to the repair line, and a pixel ground voltage lower than the pixel driving voltage is applied to the cathode electrode of the light-emitting element.
19. A display panel comprising a display area in which a plurality of subpixels are arranged, a non-display area in which a plurality of dummy subpixels are arranged, a plurality of data lines arranged in the display area, one or more dummy data lines arranged in the non-display area, a plurality of gate lines intersecting the data lines of the display area and the dummy data lines of the non-display area, and a plurality of repair lines connected to corresponding dummy subpixels across the display area and the non-display area; A data driving unit electrically connected to the data lines of the display area and the dummy data lines of the non-display area; A gate driving unit disposed in a non-display area of the above display panel and connected to the gate lines; The above display area includes at least one repaired subpixel, and The above-mentioned repaired subpixel is, It includes a light-emitting element and a driving transistor electrically isolated from the light-emitting element, At least one of the above dummy subpixels is connected to the light-emitting element of the repaired subpixel through the repair line, and The dummy subpixel connected to the above light-emitting element is, Multiple driving transistors with different channel ratios; and A display device comprising a plurality of selection transistors that select one or more of the driving transistors in response to different selection signals.
20. In Article 19 The above non-display area is, Selection signal wirings to which the above selection signal is applied; A multiplexer that outputs the above selection signal to the above selection signal wires; and A display device further comprising a level shifter connected to the selection signal wirings and level-shifting the voltage of the selection signals output from the multiplexer.

Description

Pixel circuit, display panel and display device including the same The present invention relates to a pixel circuit, a display panel including the same, and a display device. Electroluminescent display devices utilize self-emissive light-emitting elements, such as Organic Light Emitting Diodes (OLEDs), placed in each subpixel, offering the advantages of fast response speed, high luminous efficiency, brightness, and high viewing angles. In addition to fast response speed and excellent luminous efficiency, brightness, and viewing angles, electroluminescent display devices also exhibit superior contrast ratio and color reproduction because they can express black gradations as perfect black. Such electroluminescent display devices do not require a backlight unit and can be implemented on flexible materials such as plastic substrates, thin glass substrates, or metal substrates. An electroluminescent display device includes a display panel in which an image is visually reproduced. During the manufacturing process of the display panel, defective subpixels appearing as dark spots or bright spots may occur due to varying process volumes. Among these defective subpixels, repairs or defect removals can be performed through a repair process. The repair process can improve the quality and yield of the display panel. FIG. 1 is a block diagram showing a display device according to one embodiment of the present specification. FIG. 2 is a plan view showing the planar arrangement of a display panel according to one embodiment of the present specification. FIG. 3 is a cross-sectional view showing the cross-sectional structure of a display panel according to one embodiment of the present specification. FIG. 4 is a plan view showing the planar arrangement of a gate driving unit according to one embodiment of the present specification. Figures 5 and 6 are drawings showing an example in which a dummy pixel is electrically connected to a defective subpixel through a repair line. Figure 7 is a diagram showing an example of voltage drop occurring in a repaired subpixel due to parasitic resistance and parasitic capacitance. Figure 8 is a circuit diagram showing an example of a variable driving element of a dummy subpixel. Figure 9 is a diagram schematically showing the channel width and channel length of a transistor. Figure 10 is a diagram showing an example of the voltage of a light-emitting element that varies according to the channel ratio of a variable driving element. Figure 11 is a diagram showing parasitic resistance and parasitic capacitance that increase with the distance between a dummy subpixel and a repaired subpixel. Figure 12 is a diagram showing the channel ratio of a variable driving element that is varied to compensate for RC delay caused by parasitic resistance and parasitic capacitance. FIG. 13 is a waveform diagram showing an example of the slew time and settled time of the driving voltage waveform of a light-emitting element that is controlled according to a selection signal. Figure 14 is a circuit diagram showing the current flowing through the variable driving element during the slew time. Figure 15 is a circuit diagram showing the current flowing through the variable driving element during the settled time. Figure 16 is a drawing showing a normal subpixel, a repaired subpixel, and a dummy subpixel. FIG. 17 is a circuit diagram showing a pixel circuit of a subpixel placed within a display area according to one embodiment of the present invention. FIG. 18 is a circuit diagram showing a pixel circuit of a dummy subpixel according to one embodiment of the present invention. FIG. 19 is a waveform diagram showing an example of a gate signal and a select signal illustrated in FIG. 17 and FIG. 18. FIG. 20 is a circuit diagram showing a pixel circuit of a dummy subpixel according to another embodiment of the present invention. FIG. 21 is a waveform diagram showing an example of a gate signal and a select signal illustrated in FIG. 17 and FIG. 20. The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. The present invention is not limited to the embodiments disclosed below but may be implemented in various different forms; the embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are exemplary, and therefore the present invention is not limited to the matters shown in the drawings. Throughout the specification, the same reference numerals refer to substantially the same components. Furthermore, in describing the present invention, detailed descriptions of relat