Patent Application
20220172669
This Non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 109142080 filed in Taiwan, Republic of China on Nov. 30, 2020, the entire contents of which are hereby incorporated by reference.
The present disclosure relates to a display device and, in particular, to a micro light-emitting diode (LED) display device.
When the world is paying attention to future display technologies, the micro LED is one of the most promising technologies. In brief, the micro LED is a technology combining miniaturizing and matrix of LEDs, thereby placing millions or even tens of millions of dies, which are smaller than 100 microns and thinner than a hair, on a substrate. Compared with the current OLED (organic light-emitting diode) display technology, the micro LED is also self-luminous, but it does not have the most deadly “screen burn-in” problem of OLED due to the different materials used. In addition, the micro LED further has the advantages of low power consumption, high contrast, wide color gamut, high brightness, small size, thin, light weight, energy saving, etc. Therefore, major manufacturers around the world are scrambling to invest in the research and development of micro LED technology.
However, although micro LED has many advantages, there are still some technical obstacles to be overcome. For example, in a large-size, high-resolution, and high-frequency micro LED display device, the driving voltages inputted to pixels may generate voltage drops due to the different positions of pixels in the panel, and the generated voltage drops can cause uneven brightness. This is still a non-ignorable issue in the micro LED display devices.
Therefore, it is desired to provide a micro LED display device that can solve the uneven brightness problem caused by the voltage drops of driving voltages, thereby improving the display quality.
In view of the foregoing, the present disclosure is to provide a micro LED display device that can improve the uneven brightness phenomenon caused by the voltage drops of driving voltages, thereby improving the display quality.
To achieve the above, a micro LED display device of this disclosure comprises a display panel and a driving circuit unit. The display panel comprises a plurality of pixel group units arranged side by side along a first direction. Each of the pixel group units comprises a plurality of pixels extending in a second direction, and the first direction is different from the second direction. The driving circuit unit is electrically connected to the display panel. The driving circuit unit outputs a first voltage and a second voltage different from the first voltage to the pixels of each pixel group unit of the display panel. The display panel has a first side and a second side disposed in the second direction and opposite to each other. The first voltage is introduced into the display panel from the first side, and the second voltage is introduced into the display panel from the second side. The voltage bias between the first voltage and the second voltage is in positive correlation to a brightness of one of the connected pixels.
In one embodiment, the first voltage is greater than the second voltage.
In one embodiment, the first voltage is a driving voltage of the pixel group units, and the second voltage is a common voltage of the pixel group units.
In one embodiment, the first voltage is applied along the second direction to the pixels of each of the pixel group units.
In one embodiment, the second voltage is applied along a direction opposite to the second direction to the pixels of each of the pixel group units.
In one embodiment, the display panel further comprises a plurality of first connecting lines extending along the second direction, and the first voltage is applied to the pixel group units through the first connecting lines.
In one embodiment, one of the first connecting lines is disposed corresponding to one of the pixel group units.
In one embodiment, the display panel further comprises a plurality of second connecting lines extending along the second direction, and the second voltage is applied to the pixel group units through the second connecting lines along a direction opposite to the second direction.
In one embodiment, one of the second connecting lines is disposed corresponding to one of the pixel group units.
In one embodiment, the micro LED display device further comprises at least one main trace arranged between the driving circuit unit and the second connecting lines, and the second voltage is introduced into the display panel from the second side through the at least one main trace.
In one embodiment, the at least one main trace is connected to each of the second connecting lines.
In one embodiment, the micro LED display device comprises a plurality of main traces, the pixel group units are divided into a plurality of zones in the first direction, and the main traces are disposed corresponding to the zones.
In one embodiment, each of the zones includes a plurality of the second connecting lines and electrically connects to one of the main traces.
In one embodiment, the micro LED display device comprises a plurality of main traces, and the main traces are disposed corresponding to the second connecting lines.
In one embodiment, the micro LED display device further comprises a plurality of data lines, the driving circuit unit comprises a data driving circuit and a power supply circuit, the data driving circuit outputs a data signal to the pixel group units through the data lines, and the power supply circuit outputs the first voltage and the second voltage.
In one embodiment, the micro LED display device further comprises a plurality of scan lines, and the driving circuit unit comprises a scan driving circuit electrically connected to the display panel and outputs a scan signal to the pixel group units through the scan lines.
As mentioned above, in the micro LED display device of this disclosure, the display panel comprises a plurality of pixel group units arranged side by side along a first direction, and each of the pixel group units comprises a plurality of pixels extending in a second direction, which is different from the first direction; and the driving circuit unit outputs a first voltage and a second voltage to the pixels of each pixel group unit of the display panel, wherein the first voltage is introduced into the display panel from the first side of the display panel, the second voltage is introduced into the display panel from the second side of the display panel, and the voltage bias between the first voltage and the second voltage is in positive correlation to a brightness of one of the connected pixels. Accordingly, the voltage bias for driving the micro LEDs, which are added in different pixels of each pixel group unit along the second direction, can have a small deviation, thereby minimizing the deviation of the brightness of the micro LEDs of each pixel group unit. Therefore, the micro LED display device of this disclosure can improve the uneven brightness phenomenon caused by the voltage drops of driving voltages, thereby improving the display quality.
The disclosure will become more fully understood from the detailed description and accompanying drawings, which are given for illustration only, and thus are not limitative of the present disclosure, and wherein:
The present disclosure will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
Referring to
The display panel 11 is a micro LED display panel, which comprises a plurality of micro LEDs. When the micro LEDs are driven individually by the driving circuit unit 12 to emit light, the display panel 11 can display an image. In this embodiment, the display panel 11 comprises a plurality of pixel group units P1˜Pn arranged side by side along a first direction D1, wherein n is a positive integer greater than 1. Each of the pixel group units P1˜Pn comprises a plurality of pixels extending in a second direction D2, and the first direction D1 is different from the second direction D2. In this embodiment, the first direction D1 is perpendicular to the second direction D2, but this disclosure is not limited thereto. In another embodiment, the first direction D1 is not perpendicular to the second direction D2, and the included angle between the first direction D1 and the second direction D2 is, for example, an acute angle.
Specifically, the pixel group units P1˜Pn are arranged side by side along the first direction D1 (e.g. a horizontal direction herein) and disposed in the display area of the display panel 11, and each of the pixel group units P1˜Pn comprises a plurality of pixels extending in arranged along the second direction D2 (e.g. a vertical direction herein). Each pixel comprises at least one micro LED. In this embodiment, each pixel is correspondingly configured with one monochromatic micro LED (a single color), so that three adjacent pixels with different colors (e.g. red, green and blue). In other words, three adjacent RGB pixels can construct a single full-color pixel point. To be noted, each pixel group unit indicates the pixels arranged along one data line and connected to the same data line.
The pixel group unit P1 comprises the pixels P11˜P1m extending in and arranged along the second direction D2, wherein m is a positive integer greater than 1. Similarly, the pixel group unit Pn-2 comprises the pixels P(n-2)1˜P(n-2)m extending in and arranged along the second direction D2. Since the pixel group units P1˜Pn are arranged side by side along the first direction D1, and each of the pixel group units P1˜Pn comprises m pixels extending in and arranged along the second direction D2, the display panel 11 comprises totally n×m pixels P11˜Pnm. In this embodiment, the pixels P11˜Pnm of the display panel 11 are arranged in an array including n columns (the second direction D2) and m rows (the first direction D1). In addition, the display panel 11 further comprises a first side A1, a second side A2, a third side A3, and a fourth side A4. The first side A1 and the second side A2 are disposed opposite to each other in the second direction D2, and the third side A3 and the fourth side A4 are disposed opposite to each other in the first direction D1. The third side A3 is connected to the first side A1 and the second side A2, and the fourth side A4 is also connected to the first side A1 and the second side A2.
The driving circuit unit 12 is disposed next to the first side A1 of the display panel 11 and is electrically connected to the display panel 11. In this embodiment, the driving circuit unit 12 outputs a first voltage VDD and a second voltage VSS to the pixels of each of the pixel group units P1˜Pn of the display panel 11. The first voltage VDD is introduced into the display panel 11 from the first side A1 of the display panel 11, and the second voltage VSS is introduced into the display panel 11 from the second side A2 of the display panel 11. The voltage bias between the first voltage VDD and the second voltage VSS is in positive correlation to a brightness of one of the connected pixels. Herein, the term “the voltage bias between the first voltage VDD and the second voltage VSS is in positive correlation to a brightness of one of the connected pixels” means that the brightness of the corresponding pixel is relatively higher while the voltage bias between the first voltage VDD and the second voltage VSS is larger, and the brightness of the corresponding pixel is relatively lower while the voltage bias between the first voltage VDD and the second voltage VSS is smaller.
Specifically, the driving circuit unit 12 of this embodiment comprises a data driving circuit 121 and a power supply circuit 122. The power supply circuit 122 provides the first voltage VDD and the second voltage VSS. The first voltage VDD is a DC driving voltage applied to drive the light-emitting elements (i.e. micro LEDs) of the pixels P11˜Pnm of the pixel group units P1˜Pn to emit light, and the second voltage VSS is the common voltage of the pixels P11˜Pnm of the pixel group units P1˜Pn. The first voltage VDD and the second voltage VSS are introduced into the display panel 11 from two opposite sides (sides A1 and A2) of the display panel 11. In addition, the first voltage VDD is greater than the second voltage VSS. In this embodiment, for example, the first voltage VDD is 4.6V, and the second voltage VSS is −2V. To be noted, this disclosure is not limited thereto. In different embodiments, the values of the first voltage VDD and the second voltage VSS can be adjusted based on the characteristics of the micro LEDs to be driven.
The power supply circuit 122 of this embodiment outputs the first voltage VDD, which is introduced into the display panel 11 from the first side A1 of the display panel 11 through one main trace C1, and then transmitted to the pixels P11˜Pnm of the pixel group units P1˜Pn through a plurality of first connecting lines in the display area (e.g. the first connecting lines Cq and Cq+1 as shown in
In addition, the micro LED display device 1 of this embodiment further comprises a plurality of data lines D1˜Dn, and the data driving circuit 121 is electrically connected to the display panel 11 through the data lines D1˜Dn. Accordingly, the data driving circuit 121 can output a data signal along the second direction D2 and through the data lines D1˜Dn to the pixels P11˜Pnm of each of the pixel group units P1˜Pn of the display panel 11. In addition, the micro LED display device 1 of this embodiment can further comprise a plurality of scan lines S1˜Sm, and the scan driving circuit 13 is disposed next to the third side A3 of the display panel 11 and electrically connected to the display panel 11 through the scan lines S1˜Sm. Accordingly, the scan driving circuit 13 can output a scan signal along the first direction D1 and through the scan lines S1˜Sm to the pixels P11˜Pnm of each of the pixel group units P1˜Pn. In different embodiments, the scan driving circuit 13 can be disposed next to the fourth side A4 of the display panel 11 and electrically connected to the display panel 11 through the scan lines S1˜Sm. Alternatively, the scan driving circuit 13 can comprise two driving sub-circuits, which are disposed next to the third side A3 and the fourth side A4 of the display panel 11, respectively. This disclosure is not limited thereto. In some embodiments, the data driving circuit 121 and the power supply circuit 122 can be two individual driving chips, or they can be integrated as a single driving chip (i.e. the driving circuit unit 12 is a single chip), or the driving circuit unit 12 (including the data driving circuit 121 and the power supply circuit 122) and the scan driving circuit 13 can be integrated as a single driving chip. This disclosure is not limited thereto.
When the scan driving circuit 13 outputs the scan signals through the scan lines S1˜Sm to conduct (turn on) the pixels P11˜Pnm, the data driving circuit 121 can output the data signals to the corresponding pixels of each of the pixel group units P1˜Pn through the data lines D1˜Dn, respectively. Then, the power supply circuit 122 can output the first voltage VDD and the second voltage VSS to the pixels of each of the pixel group units P1˜Pn of the display panel 11 for driving or turning on the micro LEDs of the pixels P11˜Pnm of the pixel group units P1˜Pn, thereby enabling the display device to display images. Herein, the first voltage VDD is introduced into the pixels of each of the pixel group units P1˜Pn from the first side A1 of the display panel 11 through the main trace C1 and the corresponding first connecting lines in the display panel 11, and the second voltage VSS is introduced into the pixels of each of the pixel group units P1˜Pn from the second side A2 of the display panel 11 through the main trace C2 and the corresponding second connecting lines in the display panel 11.
The details of four continuous pixels Pqr, Pq(r+1), P(q+1)r and P(q+1)(r+1) in two adjacent pixel group units in the micro LED display device 1 of this embodiment will be described hereinafter with reference to
In this embodiment, the display panel 11 comprises a plurality of connecting lines extending along the second direction D2 (e.g. the first connecting lines Cq and Cq+1 as shown in
To be noted, the terms “main trace”, “first connecting line” or “second connecting line” cam be a physical conductive wire, or any circuit composed of a circuit layer or a conductive layer that can transmit electrical signals (e.g. a thin-film circuit), and this disclosure is not limited.
For example, the pixel Pqr comprises a micro LED 21, a driving transistor 22, a switch transistor 23, and a capacitor 24. The driving transistor 22 drives the micro LED 21 to illuminate. The source of the driving transistor 22 is connected to the first connecting line Cq and receives the first voltage VDD, the drain of the driving transistor 22 is connected to one terminal of the micro LED 21, and the other terminal of the micro LED 21 is connected to the second connecting line Eq for connecting the second voltage VSS. In addition, the gate of the switch transistor 23 is connected to a scan line Sr for receiving a scan signal, the drain of the switch transistor 23 is connected to a data line Dq for receiving a data signal, the source of the switch transistor 23 is connected to one terminal of the capacitor 24 and the gate of the driving transistor 22, and the other terminal of the capacitor 24 is connected to the first connecting line Cq. Accordingly, the scan signal of the scan line Sr can control to conduct (turn on) the switch transistor 23, so that the data signal of the data line Dq can be inputted to the gate of the driving transistor 22 through the switch transistor 23 for conducting the driving transistor 22. After conducting the driving transistor 22, the first voltage VDD can be transmitted to one terminal of the micro LED 21 through the first connecting line Cq and the driving transistor 22, thereby forming a voltage bias between two terminals of the micro LED 21. Accordingly, the micro LED 21 of the pixel Pqr can be turned on to emit light, and the voltage bias between the first voltage VDD and the second voltage VSS is in positive correlation to the brightness of the connected pixel Pqr.
To be noted, the common voltage (the second voltage VSS) of this embodiment is transmitted through each corresponding second connecting line of each pixel group unit to electrically connect to each micro LED.
With reference to
As shown in
After calculation, it is found that the voltage bias between two sides of the driving transistors 22 and the micro LEDs 21 in different pixels of each pixel group unit of
In an actual application embodiment, for example, when the power supply circuit 122 provides a first voltage VDD of 4.6V and a second voltage VSS of −2V, m is 100, and IR is 0.0001V, in one of the pixel group units extending in the second direction D2, the voltage bias (ΔV) between the voltages applied to the first connection line Cq and the second connection line Eq of the first pixel (x=1) of the display panel 11 is 6.085V, the voltage bias (ΔV) between the voltages applied to the first connection line Cq and the second connection line Eq of the pixel located at the ¼ position of the pixel group unit (i.e. the 25th pixel) is 5.905V, the voltage bias (ΔV) between the voltages applied to the first connection line Cq and the second connection line Eq of the pixel located at the ½ position of the pixel group unit (i.e. the 50th pixel) is 5.84V, and the voltage bias (ΔV) between the voltages applied to the first connection line Cq and the second connection line Eq of the last pixel of the pixel group unit (i.e. the mth pixel) is 6.085V. The results prove that the design of this disclosure can indeed keep the voltage differences between the voltages bias for driving the driving transistors 22 and the micro LEDs 21 (i.e. the voltages applied to the first connection line Cq and the second connection line Eq) of different pixels almost the same regardless the distances between the signal input terminal and the pixels. In addition, the voltage bias between the first voltage VDD and the second voltage VSS of pixels at different locations are approximating to each other.
Referring to
As shown in
Specifically, in this embodiment, the second voltage VSS applied from the main trace C21 is transmitted to the pixel group units in the zone Z1 through the corresponding second connecting lines, the second voltage VSS applied from the main trace C22 is transmitted to the pixel group units in the zone Z2 through the corresponding second connecting lines, and the second voltage VSS applied from the main trace C23 is transmitted to the pixel group units in the zone Z3 through the corresponding second connecting lines. Although the pixel group units of the display panel 11 are corresponding to the second connecting lines, the second connecting lines corresponding to the three zones Z1, Z2 and Z3 in the display area are not connected to each other. This design can improve the uneven brightness phenomenon of the pixels in three zones Z1, Z2 and Z3 along the first direction D1. Of course, in different embodiments, the second connecting lines corresponding to the three zones Z1, Z2 and Z3 in the display area can be connected to each other, and this disclosure is not limited.
In some embodiments, the amount of the main traces for transmitting the second voltage VSS can be equal to the amount of the second connecting lines or the pixel group units, and they are correspondingly connected to each other in the one-by-one manner for transmitting the second voltage to the pixel group unit through the corresponding main trace and the corresponding second connecting line. That is, one main trace is corresponding to and connected to one second connecting line and one pixel group unit. To be noted, this disclosure is not limited thereto.
In summary, in the micro LED display device of this disclosure, the display panel comprises a plurality of pixel group units arranged side by side along a first direction, and each of the pixel group units comprises a plurality of pixels extending in a second direction, which is different from the first direction; and the driving circuit unit outputs a first voltage and a second voltage to the pixels of each pixel group unit of the display panel, wherein the first voltage is introduced into the display panel from the first side of the display panel, the second voltage is introduced into the display panel from the second side of the display panel, and the voltage bias between the first voltage and the second voltage is in positive correlation to a brightness of one of the connected pixels. Accordingly, the voltage bias for driving the micro LEDs, which are added in different pixels of each pixel group unit along the second direction, can have a small deviation, thereby minimizing the deviation of the brightness of the micro LEDs of each pixel group unit. Therefore, the micro LED display device of this disclosure can improve the uneven brightness phenomenon caused by the voltage drops of driving voltages, thereby improving the display quality.
Although the disclosure has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 109142080 | Nov 2020 | TW | national |
