This application claims priority to Korean Patent Application No. 10-2023-0009407, filed in the Republic of Korea on Jan. 25, 2023, the entire contents of which are hereby expressly incorporated by reference into the present application.
The present disclosure relates to a display device and a method of driving the same.
As information technology develops, the market for display devices, which are communication media between users and information, is growing. Accordingly, display devices such as a light emitting display (LED) device, a quantum dot display (QDD) device, and a liquid crystal display (LCD) device are increasingly used.
The display devices described above include a display panel including sub-pixels, a driver that outputs driving signals for driving the display panel, and a power supply that generates power to be supplied to the display panel or the driver.
In the above-described display devices, when driving signals, for example, a scan signal and a data signal, are supplied to the sub-pixels formed in the display panel, selected sub-pixels transmit light or directly emit light, thereby displaying an image.
Accordingly, the present disclosure is directed to a display device and a method of driving the same that substantially obviate one or more problems due to limitations and disadvantages of the related art.
The present disclosure enhances display quality by compensating for or improving current deviations that can be caused by physical separation of voltage lines through which a voltage is transmitted to a display panel by a plurality of circuit boards or a plurality of cables.
Additional advantages, objects, and features of the disclosure will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or can be learned from practice of the disclosure. The objectives and other advantages of the disclosure can be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these objects and other advantages and in accordance with the purpose of the disclosure, as embodied and broadly described herein, a display device includes a display panel configured to display images, a plurality of circuit boards connected to one side of the display panel, a cable electrically connecting at least two of the plurality of circuit boards, voltage lines disposed on the cable, the plurality of circuit boards, and the display panel, a deviation compensation circuit configured to sense voltages transmitted through a circuit board on one side and a circuit board on the other side connected by the cable among the plurality of circuit boards and to output a signal based on the sensed voltages, and a variable circuit configured to compensate for a current difference between the circuit board on one side and the circuit board on the other side based on the signal output from the deviation compensation circuit.
The variable circuit can include at least one variable resistor configured to vary resistance values of the voltage lines based on the signal output from the deviation compensation circuit.
The variable circuit can include at least one transistor configured to vary an amount of current flowing through the voltage lines based on the signal output from the deviation compensation circuit.
The deviation compensation circuit can output a signal for controlling an on/off duty ratio of the at least one transistor.
The variable circuit can be disposed between voltage lines formed in a display area of the display panel.
The variable circuit can include at least one transistor configured to block a current flowing through the voltage lines formed in the display area of the display panel.
The deviation compensation circuit can output a signal for controlling on/off of the transistor.
The variable circuit can be disposed on at least one of the circuit board on one side and the circuit board on the other side.
The deviation compensation circuit can be disposed on one selected from the circuit board on one side, the circuit board on the other side, and the cable.
In another aspect of the present disclosure, a method of driving a display device including a display panel configured to display images, a plurality of circuit boards connected to one side of the display panel, a cable electrically connecting at least two of the plurality of circuit boards, voltage lines disposed on the cable, the plurality of circuit boards, and the display panel, a deviation compensation circuit configured to sense voltages transmitted through a circuit board on one side and a circuit board on the other side connected by the cable among the plurality of circuit boards and to output a signal based on the sensed voltage, and a variable circuit electrically connected to the deviation compensation circuit includes sensing voltages transmitted through the circuit board on one side and the circuit board on the other side, outputting a signal for controlling the variable circuit based on the voltages sensed from the circuit board on one side and the circuit board on the other side, and compensating for a current difference between the circuit board on one side and the circuit board on the other side based on the signal.
It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed.
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the disclosure and together with the description serve to explain the principle of the disclosure. In the drawings:
Reference will now be made in detail to the preferred embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
A display device according to the embodiments of the present disclosure can be implemented as a television system, an image player, a personal computer (PC), a navigation device, a wearable electronic device, a home theater, an automobile electric device, a smartphone, or the like, but is not limited thereto. The display device according to the embodiments of the present disclosure can be implemented as a light emitting display (LED) device, a quantum dot display (QDD) device, a liquid crystal display (LCD) device, or the like. However, as an example, a light emitting display device that directly emits light based on inorganic light emitting diodes or organic light emitting diodes will be described below for convenience of description. Further, all components of each display device according to all embodiments of the present disclosure are operatively coupled and configured.
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The image provider (set system or host system) 110 can output various driving signals along with an externally supplied image data signal or an image data signal stored in an internal memory. The image provider 110 can supply data signals and various driving signals to the timing controller 120.
The timing controller 120 can output a gate timing control signal GDC for controlling operation timing of the gate driver 130, a data timing control signal DDC for controlling operation timing of the data driver 140, and various synchronization signals (a vertical synchronization signal VSYNC and a horizontal synchronization signal HSYNC). The timing controller 120 can supply a data signal DATA supplied from the image provider 110 to the data driver 140 along with the data timing control signal DDC. The timing controller 120 can be implemented in the form of an integrated circuit (IC) and mounted on a printed circuit board, but is not limited thereto.
The gate driver 130 can output a gate signal (or a gate voltage) in response to the gate timing control signal GDC supplied from the timing controller 120. The gate driver 130 can supply the gate signal to sub-pixels included in the display panel 150 through gate lines GL1 to GLm where m can be a positive number such as a positive integer. The gate driver 130 can be implemented in the form of an IC or directly formed on the display panel 150 in a gate-in-panel structure, but is not limited thereto.
The data driver 140 can sample and latch the data signal DATA in response to the data timing control signal DDC supplied from the timing controller 120, convert the digital data signal into an analog data voltage on the basis of a gamma reference voltage, and output the analog data voltage. The data driver 140 can supply data voltages to the sub-pixels included in the display panel 150 through data lines DL1 to DLn where n can be a positive number such as a positive integer. The data driver 140 can be implemented in the form of an IC and mounted on the display panel 150 or mounted on a printed circuit board, but is not limited thereto.
The power supply 180 can generate a high-potential voltage and a low-potential voltage on the basis of an external input voltage supplied from the outside, and output the same through a first voltage line EVDD and a second voltage line EVSS. The power supply 180 can generate and output a voltage required to drive the gate driver 130 or a voltage required to drive the data driver 140 as well as the high-potential voltage and the low-potential voltage.
The display panel 150 can display an image in response to driving signals including gate signals and data voltages and driving voltages including the high-potential voltage and the low-potential voltage. Sub-pixels of the display panel 150 directly emit light. The display panel 150 can be manufactured based on a rigid or flexible substrate such as glass, silicon, or polyimide. Further, the sub-pixels emitting light can include red, green, and blue pixels or red, green, blue, and white pixels.
For example, one sub-pixel SP can be connected to the first data line DL1, the first gate line GL1, the first voltage line EVDD, and the second voltage line EVSS, and can include a pixel circuit composed of a switching transistor, a driving transistor, a capacitor, an organic light emitting diode, and the like. Since sub-pixels SP used in a light emitting display device directly emit light, the circuit configuration thereof is complicated. Further, there are various organic light emitting diodes emitting light and various compensation circuits for compensating for deterioration of driving transistors that supply driving current necessary to drive the organic light emitting diodes. Accordingly, it is noted that the sub-pixel SP is simply illustrated in the form of a block.
Meanwhile, in the above description, the timing controller 120, the gate driver 130, and the data driver 140 are individual components. However, one or more of the timing controller 120, the gate driver 130, and the data driver 140 can be integrated into one IC depending on a light emitting display device implementation method.
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The timing controller 120 can be mounted on the first circuit board 125, and the data drivers 140a to 140h can be mounted on the third circuit boards 145a to 145h, respectively. It is noted that a scan driver is not shown since it can be formed in a non-display area of the display panel 150 in a gate-in-panel structure, and a power supply is not shown since it can be mounted at different positions depending on light emitting display device implementation methods.
The first cables 121a to 121d can serve to electrically connect the first circuit board 125 and the second circuit boards 141a to 144d, and the second cables 142a and 142b can serve to electrically connect the second circuit boards 141a to 144d.
The (1-1)-th cable 121a and the (1-2)-th cable 121b can serve to electrically connect the first circuit board 125 and the (2-2)-th circuit board 141b, and the (1-3)-th cable 121c and the (1-4)-th cable 121d can serve to electrically connect the first circuit board 125 and the (2-3)-th circuit boards 141c. The (2-1)-th cable 142a can serve to electrically connect the (2-1)-th circuit board 141a and the (2-2)-th circuit board 141b, and the (2-2)-th cable 142b can serve to electrically connect the (2-3)-th circuit board 141c and the (2-4)-th circuit board 141d.
The first circuit board 125 and the second circuit boards 141a to 144d can be printed circuit boards (PCBs) or the like. The third circuit boards 145a to 145h can be flexible printed circuit boards (FPCBs) or the like. The first cables 121a to 121d and the second cables 142a and 142b can be flexible flat cables (FFCs) or the like. The first cables 121a to 121d and the second cables 142a and 142b can provide communication interfaces (data transmission lines) through which the timing controller 120 and the data drivers 140a to 140h can perform data communication and provide lines (wirings) for transmitting various signals or power.
According to the first embodiment, the light emitting display device can include a first deviation compensation circuit 160a and a second deviation compensation circuit 160b. The first deviation compensation circuit 160a and the second deviation compensation circuit 160b can serve to compensate for current deviations that can be caused by physical separation of voltage lines for transmitting voltages to the display panel 150 by a plurality of circuit boards or a plurality of cables.
Accordingly, the positions where the first deviation compensation circuit 160a and the second deviation compensation circuit 160b are disposed are not limited to those shown in
As shown in
Hereinafter, in order to aid in understanding related to the first deviation compensation circuit 160a, an example in which the second voltage line among the voltage lines PWRL disposed in the area shown in
If the second voltage line EVSS disposed on the display panel 150, the (3-1)-th circuit board 145a to the (3-4)-th circuit board 145d, the (2-1)-th circuit board 141a, the (2-2)-th circuit board 141b, and the (2-1)-th cable 142a shown in
As shown in
The first deviation compensation circuit 160a can use a first variable circuit 165a disposed on the (2-2)-th circuit board 141b in order to compensate for a difference between the second voltage transmitted through the (2-1)-th circuit board 141a and the second voltage transmitted through the (2-2)-th circuit board 141b, which will be described as follows.
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The first variable circuit 165a can include variable resistors VR1 to VR8. The first variable resistor VR1 to the eighth variable resistor VR8 can have variable resistance values corresponding to first to eighth variable signals VRC1 to VRC8 output through the output terminal of the first deviation compensation circuit 160a. Although
The first variable resistor VR1 to the eighth variable resistor VR8 disposed on the (2-2)-th circuit board 141b can be regarded as variable forms of resistors RR9 and RR10 (wiring resistance of the second voltage line) disposed on the (2-1)-th circuit board 141a. For example, the first variable resistor VR1 to the eighth variable resistor VR8 are compensation resistors capable of varying the resistance value for each position of the second voltage line.
The first deviation compensation circuit 160a can sense the second voltage transmitted through the second voltage line EVSS_141a disposed on the (2-1)-th circuit board 141a, which is one side L1 of the (2-1)-th cable 142a, and the second voltage line EVSS_141b disposed on the (2-2)-th circuit board 141b, which is the other side L2 of the (2-1)-th cable 142. The first deviation compensation circuit 160a can determine a difference between the second voltages sensed through the two input terminals based on a differential amplifier and the like, but the present disclosure is not limited thereto.
The first deviation compensation circuit 160a can output variable signals VRC1 to VRC8 for varying the resistance value of the first variable circuit 165a disposed on the (2-2)-th circuit board 141b in order to compensate for a difference between the second voltage transmitted through the (2-1)-th circuit board 141a and the second voltage transmitted through the (2-2)-th circuit board 141b based on the sensed voltage. The first deviation compensation circuit 160a can vary the levels of the voltages of the variable signals VRC1 to VRC8 as shown in Table 1 below in order to vary the resistance value of the first variable circuit 165a, but the present disclosure is not limited thereto.
The first deviation compensation circuit 160a can output a signal for varying at least one of the first variable resistors VR1 to the eighth variable resistors VR8 without outputting a signal for varying all thereof. For example, the first deviation compensation circuit 160a can vary the resistance value of at least one of the first variable resistor VR1 to the eighth variable resistor VR8 in response to the difference between the second voltages sensed through the two input terminals.
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The first variable circuit is disposed only on the (2-2)-th circuit board in the first example (2), and the first variable circuit is disposed on both the (2-1)-th circuit board and the (2-2)-th circuit board in the second example (3). As can be ascertained with reference to the comparative example (1), the first example (2), and the second example (3), it is possible to compensate for (improve) current deviations that can be caused by physical separation of the second voltage lines for transmitting the second voltage to the display panel by a plurality of circuit boards or a plurality of cables by using the deviation compensation circuit and the first variable circuit.
As shown in
Hereinafter, in order to aid in understanding related to the first deviation compensation circuit 160a, an example in which the second voltage line among the voltage lines PWRL disposed in the area shown in
If the second voltage line EVSS disposed on the display panel 150, the (3-1)-th circuit board 145a to the (3-4)-th circuit board 145d, the (2-1)-th circuit board 141a, the (2-2)-th circuit board 141b, and the (2-1)-th cable 142a shown in
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The second variable circuit 166a can include transistors T1 to T8. The first transistor T1 to the eighth transistor T8 can be turned on or off in response to first to eighth control signals TC1 to TC8 output through the output terminal of the first deviation compensation circuit 160a. The first to eighth transistors T1 to T8 disposed on the (2-2)-th circuit board 141b are compensation transistors capable of controlling the current flowing through the second voltage line. Although
The first deviation compensation circuit 160a can sense the second voltage transmitted through the second voltage line EVSS_141a disposed on the (2-1)-th circuit board 141a, which is one side L1 of the (2-1)-th cable 142a, and the second voltage line EVSS_141b disposed on the (2-2)-th circuit board 141b, which is the other side L2 of the (2-1)-th cable 142a. The first deviation compensation circuit 160a can determine a difference between the second voltages sensed through the two input terminals based on a differential amplifier and the like, but the present disclosure not limited thereto.
The first deviation compensation circuit 160a can output control signals TC1 to TC8 for controlling an on/off duty ratio (varying a pulse width) of the second variable circuit 166a disposed on the (2-2)-th circuit board 141b in order to compensate for a difference between the current transmitted through the (2-1)-th circuit board 141a and the current transmitted through the (2-2)-th circuit board 141b based on the sensed voltage.
The first deviation compensation circuit 160a can output a signal for individually controlling (independently controlling for each channel) at least one of the first to eighth transistors T1 to T8 instead of outputting a signal for turning on/off all of the first to eighth transistors T1 to T8. For example, the first deviation compensation circuit 160a can sense voltages through the two input terminals, determine a current difference based on the sensed voltages, and independently control the amount of current flowing through at least one of the first to eighth transistors T1 to T8 based on the current difference.
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The third variable circuit 167a can include transistors T1 to T5. The transistors T1 to T5 can be disposed at a branch point between the second voltage line EVSS_150 disposed on one side L1 of the display panel 150 and the second voltage line EVSS_150 disposed on the other side L2 of the display panel 150. The first transistor T1 to the fifth transistor T5 disposed at the branch points between one side L1 and the other side L2 of the display panel 150 are compensation transistors capable of blocking a voltage or a current flowing through a branch point of the second voltage lines disposed in the horizontal direction of the display area. Although
The first transistor T1 to the fifth transistor T5 can be turned on or off in response to first to fifth control signals TC1 to TC5 output through the output terminal of the first deviation compensation circuit 160a.
The first deviation compensation circuit 160a can sense the second voltage transmitted through the second voltage line EVSS_141a disposed on the (2-1)-th circuit board 141a, which is one side L1 of the (2-1)-th cable 142a, and the second voltage line EVSS_141b disposed on the (2-2)-th circuit board 141b, which is the other side L2 of the (2-1)-th cable 142a. The first deviation compensation circuit 160a can determine a difference between the second voltages sensed through the two input terminals based on a differential amplifier and the like, but the present disclosure is not limited thereto.
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The first deviation compensation circuit 160a can output a signal for individually (independently) controlling at least one of the first transistor T1 to the fifth transistor T5 instead of outputting a signal for turning on/off all of the transistors T1 to T5. For example, the first deviation compensation circuit 160a can sense voltages through two input terminals and control (independently control for each channel) on/off of at least one of the first to fifth transistors T1 to T5 based on the sensed voltages. Hereinafter, a case where there is no difference between the sensed voltages and a case where there is a difference therebetween will be described.
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As can be ascertained with reference to
Meanwhile, the first to third embodiments have been separately described in the present disclosure. However, one or more of the first to third embodiments can be combined in order to improve compensation accuracy at the time of compensating for (improving) current deviations.
As described above, the present disclosure has an effect of compensating for or improving current deviations that can be caused by physical separation of voltage lines through which a voltage is transmitted to a display panel by a plurality of circuit boards or a plurality of cables. In addition, the present disclosure has an effect of improving display quality by compensating for or improving current deviations that can occur in the display panel.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the spirit or scope of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of the disclosure provided they come within the scope of the appended claims and their equivalents.
Number | Date | Country | Kind |
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10-2023-0009407 | Jan 2023 | KR | national |