KR-20260062916-A - PIXEL AND DISPLAY DEVICE HAVING THE SAME

KR20260062916AKR 20260062916 AKR20260062916 AKR 20260062916AKR-20260062916-A

Abstract

A pixel comprises: a light-emitting element; a first node connected to a first driving power source; a second node connected to the anode electrode of the light-emitting element; a first transistor connected between the first node and the second node and having a gate electrode connected to a third node; a second transistor connected between a data line and the first node and turned on by a first scan signal applied through a first scan line; a third transistor connected between the second node and the third node and turned on by a second scan signal applied through a second scan line; a fourth transistor connected between the third node and the first initialization power source and turned on by a third scan signal applied through a third scan line; a first capacitor connected between the first driving power source and the third node; and a second capacitor having an input electrode and an output electrode, connected to the third node through the output electrode to boost the voltage of the gate electrode of the first transistor in response to a voltage change of the input electrode.

Inventors

박준현
정민재
강장미

Assignees

삼성디스플레이 주식회사

Dates

Publication Date: 20260507
Application Date: 20260422

Claims (12)

Light-emitting element; A first node connected to a first driving power source; A second node connected to the anode electrode of the light-emitting element; A first transistor having a gate electrode connected between the first node and the second node and connected to a third node; A second transistor connected between the data line and the first node, and turned on by a first scan signal applied through the first scan line; A third transistor connected between the second node and the third node, and turned on by a second scan signal applied through a second scan line; A fourth transistor connected between the third node and the first initialization power supply and turned on by a third scan signal applied through a third scan line; A first capacitor connected between the first driving power source and the third node; and A pixel having an input electrode and an output electrode, and including a second capacitor connected to the third node through the output electrode to boost the voltage of the gate electrode of the first transistor in response to a voltage change of the input electrode.
In claim 1, the pixel comprises the first transistor and the second transistor, each comprising different types of thin-film transistors.
A pixel according to claim 1, wherein the first transistor comprises a P-type thin-film transistor and the third transistor comprises an N-type thin-film transistor.
In claim 1, each of the third and fourth transistors comprises a pixel including an oxide semiconductor thin film transistor.
In claim 1, the second capacitor is connected to the first scan line through the input electrode and boosts the voltage of the gate electrode of the first transistor in response to the first scan signal.
A pixel according to claim 1, further comprising a fifth transistor connected between a second initialization power source and the anode electrode of the light-emitting element and turned on by a fourth scan signal applied through a fourth scan line.
In claim 6, the second capacitor is connected to the fourth scan line through the input electrode and boosts the voltage of the gate electrode of the first transistor in response to the fourth scan signal.
In claim 6, the pixel is configured to receive the first scan signal multiple times during one frame period, and A pixel comprising an active period in which the second and third scan signals are supplied, and a blank period in which the second and third scan signals are not supplied.
In claim 8, the first scan signal is a pixel supplied during the blank period.
In claim 9, the fourth scan signal is additionally supplied during the blank period, and the fourth scan signal is a pixel that overlaps with the first scan signal.
In Article 6, A sixth transistor connected between the first driving power source and the first node; and It further includes a seventh transistor connected between the second node and the anode electrode of the light-emitting element, The pixel configured such that the 6th and 7th transistors are controlled by at least one light emission control signal.
In claim 11, the pixel is such that each of the first, second, fifth, sixth, and seventh transistors is a P-type low-temperature polysilicon thin-film transistor, and each of the third and fourth transistors is an N-type oxide semiconductor thin-film transistor.

Description

Pixel and display device having the same The present invention relates to a pixel and a display device including the same. The display device includes a display panel comprising a plurality of pixels and a driving unit for driving the display panel. The driving unit displays an image on the display panel using an image signal received from an external graphics processor. The graphics processor generates an image signal by rendering raw data, and the rendering time for generating an image signal corresponding to one frame may vary depending on the type or characteristics of the image. The driving unit may vary the driving frequency (or frame frequency) in response to the rendering time. A pixel may include a pixel circuit comprising a plurality of transistors and capacitors and a light-emitting element. When a scan signal is supplied from a scan line, the pixel circuit receives a data voltage from a data line and can supply a current of a driving transistor corresponding to the data voltage to the light-emitting element. The light-emitting element can emit light with an intensity corresponding to the current of the driving transistor. When the display device is driven at a low driving frequency, a frame may include an active period during which a data signal is written and a blank period during which no data signal is written. During the blank period, a difference in brightness may occur between the active period and the blank period due to leakage current and/or hysteresis characteristics of the driving transistor. To improve this, the display device may supply multiple on-bias voltages to the driving transistor during the active period and the blank period, respectively. A display device for realizing high resolution may supply data voltage and bias voltage through a single data line to reduce wiring. In this case, among multiple pixels connected to the same data line during the active period, the time at which bias voltage is applied to pixels positioned above the middle of the display panel and the time at which data is written to pixels positioned below may overlap. As a result, a ghosting phenomenon may occur in which a pattern displayed on the lower part of the display panel is displayed as an afterimage on the upper part. FIG. 1 is a block diagram showing a display device according to embodiments of the present invention. FIG. 2 is a drawing showing an example of a scan driving unit included in the display device of FIG. 1. Figure 3 is a circuit diagram showing an example of a pixel included in the display device of Figure 1. FIG. 4 is a drawing showing an example of variable frequency driving of the display device of FIG. 1. FIG. 5a is a waveform diagram showing an example of operation during the active period of the display device of FIG. 1. FIGS. 5B and FIGS. 5C are waveform diagrams showing an example of operation during the blank period of the display device of FIG. 1. FIG. 6 is a waveform diagram showing an example of operation during the active period of the display device of FIG. 1. Figure 7 is a diagram illustrating the ghosting phenomenon that occurs on the display panel due to the operation of Figure 6. FIG. 8 is a circuit diagram showing an example of a pixel included in the display device of FIG. 1. In this case, the pixel (PX2) is a pixel placed in the i-th row and j-th column (where i and j are natural numbers). Figure 9 is a diagram illustrating the ghosting prevention effect of the pixel shown in Figure 8. The present invention is capable of various modifications and may take various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the invention to the specific disclosed forms, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention. In describing each drawing, similar reference numerals have been used for similar components. In the attached drawings, the dimensions of the structures are depicted enlarged from their actual size for clarity of the invention. Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the invention, the first component may be named the second component, and similarly, the second component may be named the first component. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, a