KR102142475B1 - Display Device And Driving Method Of The Same - Google Patents

Abstract

The present invention includes a pixel region defined by first and second gate lines and a first data line; A first thin film transistor formed in the pixel area and connected to the first gate line and the first data line; A second thin film transistor formed in the pixel area and connected to the second gate line and the first data line; It provides a display device including at least one gate driver that is connected to the first and second gate lines and transmits a gate signal at a different refresh rate for each pixel area.

Description

Display device and driving method of the same

The present invention relates to a display device and a method of driving the low refresh rate driving and the normal refresh rate driving.

A display device is a device that displays a video by driving a thin film transistor according to input of image data by forming a plurality of thin film transistors on a substrate.

Typical display devices include liquid crystal display devices that control the amount of light passing through a substrate by changing the arrangement of liquid crystals, and the amount of voltage applied by placing an organic material to recombine electrons and holes. There is an organic light emitting diode display device that controls the amount of light by adjusting.

A conventional display device uses a method of displaying image by transmitting image data according to a constant driving scan rate. This is to compensate for the voltage retention ability using a thin film transistor including amorphous silicon (a-Si), which is a conventional display device having a low ability to maintain voltage, thereby increasing power consumption. have.

However, in the recently proposed oxide thin film transistor (Oxide Thin Film Transistor), since the ability to maintain the applied voltage has a characteristic of having a low off current (Off Current) compared to amorphous silicon, so that unnecessary power consumption is reduced. A low refresh rate display device that increases the transmission period of image data for a still image has been proposed. This will be described with reference to FIG. 1 below.

1 is an algorithm for driving a conventional display device displaying first image data.

As shown in FIG. 1, a conventional display device displaying first image data selects low scan rate driving and general scan rate driving in the step of applying the second image data.

At this time, it will be described as an example that the conventional display device is driven at 60Hz.

The low scan rate driving is for transmitting image data for one frame (16.7msec) and blocking the image data for 59 frames, and the general scan rate driving is described as an example of continuously transmitting image data for 60 frames.

In a first step (S01 ), the first image data is displayed on the display device.

Thereafter, in the second step S02, the second image data to be displayed after the displayed first image data is received.

Thereafter, in the third step S03, the first image data and the second image data are compared. According to the result of the comparison, when the first image data and the second image data completely match, the display device displays the second image data at a low scanning rate.

On the other hand, when the first image data and the second image data do not completely match, the display device displays the second image data at a normal refresh rate.

The conventional display device repeats the algorithm shown in FIG. 1 to perform low scan rate driving on a still image and general scan rate driving on a changing image such as a moving image to reduce power consumed during a time to display a still image and Here it is.

However, in the conventional display device, even if there is a difference between the first image data and the second image data even in a part of the received image data, since the normal refresh rate driving is performed immediately, the substantially reduced power consumption was not high and the entire screen was low. When the image data is updated while performing the scan rate driving, the quality of the displayed image is lowered due to the inability to respond immediately, resulting in a decrease in efficiency compared to the reduced power consumption.

In the present invention, even when displaying a still image, the low scan rate driving display device proposed to compensate for the problem of increasing the power consumption by performing a high scan rate driving is performed even when a part of the image changes. It is intended to solve the problem that the efficiency of reduction of power consumption is greatly reduced and the image quality is deteriorated due to the conversion from the low scan rate driving to the normal scan rate driving.

In order to solve the above problems, the present invention provides a pixel region defined by first and second gate lines and a first data line; A first thin film transistor formed in the pixel area and connected to the first gate line and the first data line; A second thin film transistor formed in the pixel area and connected to the second gate line and the first data line; It provides a display device including at least one gate driver that is connected to the first and second gate lines and transmits a gate signal at a different refresh rate for each pixel area.

In addition, the gate driver includes a level shift formed with a channel output unit and first and second input units.

In addition, the gate driver further includes a scan change circuit that is connected between the first and second input units and controls the output signal of the channel output unit according to the level of the input signal.

Moreover, the scan change circuit is connected between the first and second input units, and is characterized in that it includes an inverting unit that receives the input signal.

On the other hand, the present invention, displaying the first image data on the panel; Receiving second image data; Comparing the first image data and the second image data; Separating a first display area in which the first image data and the second image data are identical, and a second display area in which the first image data and the second image data are different; Displaying the first image data or the second image data at a first scanning rate in the first display area; And displaying the second image data at a second scan rate higher than the first scan rate in the second display area.

In addition, the first and second display areas include one or more pixels defined by intersections of gate lines and data lines.

In addition, the first scan rate outputs data for a gate signal or data signal for one frame and then blocks the output of the gate signal or the data signal for the remaining 59 frames, and 60 when displaying an image at the second scan rate. It is characterized by outputting the gate signal or the data signal during a frame.

In the display device and driving method according to the present invention, the screen is divided into a predetermined area to perform a general refresh rate driving only in an area where a change occurs in an image, and other areas not only reduce power consumption by performing a low refresh rate driving, but also change There is an advantage that it is possible to minimize the image quality degradation due to the change in the scan rate by driving at a normal scan rate only in the region where the occurs.

1 is an algorithm for driving a conventional display device displaying first image data.
2 is a circuit diagram showing a part of a substrate of a display device according to an exemplary embodiment of the present invention, and FIG. 3 is a waveform diagram showing a signal output from a gate driver when driving a low refresh rate of the display device according to an exemplary embodiment of the present invention.
4A and 4B are circuit diagrams showing scan change circuits added to data and gate drivers to drive the circuits generated according to the first to third embodiments of the present invention.
5 is a view showing driving of a display device having a circuit according to an embodiment of the present invention.

Hereinafter, a display device and a driving method thereof according to an embodiment of the present invention will be described with reference to the drawings.

2 is a circuit diagram showing a part of a substrate of a display device according to an exemplary embodiment of the present invention, and FIG. 3 is a waveform diagram showing a signal output from a gate driver when driving a low refresh rate of the display device according to an exemplary embodiment of the present invention.

2, the display device according to the first embodiment of the present invention includes first to second PN pixels defined by first to second N gate lines G1 to 2N and first data line D1. The first and second thin film transistors TR1 and TR2 are formed in each of the regions P1 to PN, and the structure of the liquid crystal display device is illustrated in the drawing, but the embodiment of the present invention is applied to the organic light emitting diode display device. If you do, you can change it to show the same effect by adding a common voltage circuit and switching and driving transistors.

At this time, the capacitor (C _LC ) shown in the drawing means a capacitor formed of a liquid crystal, and additionally, a storage capacitor region may be formed to increase the capacitor capacity.

The odd-numbered gate lines (G1, G3, ..., G(2N-1)) are for performing low scan rate driving for each lateral area of the display device, and the even-numbered gate lines (G2, G4, ..., G( 2N)) is for performing general refresh rate driving for each lateral region of the display device, and includes two gate lines and two thin film transistors TR1 and TR2 in one pixel.

The first thin film transistor TR1 is connected to the first gate line G1 and performs driving of a pixel by receiving an image data signal for one frame and blocking the image data signal for 59 frames when performing low scan rate driving. The second thin film transistor TR2 is connected to the second gate line G2, and continuously performs image driving by receiving an image data signal for 60 frames during normal scan rate driving.

The data lines D1 and D2 and the gate lines G1 to G(2N) are respectively connected to the data driver and the gate driver. The gate driver transmits a gate signal at different refresh rates for each gate line (G1 to G(2N)) and applies them to each transistor. Accordingly, the panel is divided into a plurality of horizontal regions and driven at different refresh rates for each horizontal region. Can be.

For example, as shown in FIG. 3, when an image is changed in the second horizontal region B2 among the image data output from the first to third gate drivers DIC1 to DIC3, the first and third horizontal regions ( B1 and B3) supply a gate signal for one frame to apply a data signal to the pixel, and block the gate signal for the remaining 59 frames to apply a data signal to the pixel and continuously supply a gate signal for 60 frames to transmit the data signal Can be applied to a pixel.

That is, it is possible to drive a low scan rate by dividing regions for each gate line.

Although this driving may be performed in various forms, in the embodiment of the present invention, a structure in which a level shift and a scan change circuit are connected thereto is taken as an example, which will be described with reference to FIGS. 4A and 4B below.

4A is a circuit diagram showing a scan change circuit added to a gate driver to drive a circuit generated according to a first embodiment of the present invention for each gate driver, and FIG. 4B is generated according to a second embodiment of the present invention It is a circuit diagram showing the scan change circuit added to the data and gate drivers to drive the circuits for each channel.

As shown in FIG. 4A, the scan change circuit 105 includes first and second inputs of a level shifter (106) that controls V _P (Positive Voltage Output) output and V _N (Negative Voltage Output) output ( It is connected between In1 and In2) and includes an inverting part 111 to determine the output of the channels formed in the level shifter 106.

That is, for the circuit as shown in FIG. 4A, when the signal Vin input to the scan change circuit 105 is low, the outputs of the first to sixth channels (ch1 to ch6) of the level shifter 106 are cut off and high. In this case, the outputs of the first to sixth channels ch1 to ch6 are driven to be normally output.

For example, when the level shifter 106 connected to the scan change circuit 105 performs low scan rate driving, the scan change circuit 105 transmits a high signal to output a signal for one frame so that the level shifter 106 Signals are output from the first to sixth channels (ch1 to ch6) formed in, and the low signal is transmitted so that the signal is blocked for the remaining 59 frames.

On the other hand, as shown in FIG. 4B in which circuits capable of driving low scan rates and normal scan rates are formed in all pixel lines connected to the data driver as well as the gate driver, the first and second scan change circuits 105a and 105b It is connected to the level shifter 106.

In this figure, the first scan change circuit 105a controls the outputs of the first to third channels ch1 to 3 of the level shifter 106, and the first and second inputs of the level shifter 106 (In1 , In2) to perform or block the output of the first to third channels (ch1 to ch3), and the second scan change circuit 105b is the fourth to sixth channels (ch4 to ch6) of the level shifter 106 ), which is connected to the third and fourth inputs In3 and In4 of the level shifter 106 to perform or block the output of the fourth to sixth channels ch4 to ch6.

The first and second scan change circuits 105a and 105b have the same structure as the scan change circuit (105 in FIG. 5A) and are provided with inverting parts 111 and 112, respectively.

For example, when the signal Vin1 input to the first scan change circuit 105a is low, and the signal Vin2 input to the second scan change circuit 105b is high, the level shifter 106 eliminates the signal. The output of the 1 to 3 channels (ch1 to ch3) is cut off, and the 4 to 6 channels (ch4 to ch6) are driven to be output normally.

The level shifter 106 configured as described above can drive the fourth to sixth channels (ch4 to ch6) even when the first to third channels (ch1 to ch3) are blocked. The effect can be further increased.

In addition, it will be appreciated that, when further adding such a structure, it is possible to perform low scan rate driving and general scan rate driving for each channel.

In particular, the scan change circuit 105 and the level shifter 106 according to FIGS. 4A and 4B are examples of structures for driving according to the first and second embodiments of the present invention. The output of the gate signal and data signal is cut off in the remaining frames except for the time frame, and the gate signal and data signal are output from all frames when driving the normal refresh rate. It includes a method of dividing one panel region by region and driving each with a different refresh rate.

The display device including the scan change circuit 105 may divide the panel area and receive a low scan rate driving signal and a general scan rate driving signal output from a data driver or a gate driver. Explain.

5 is a view showing driving of a display device having a circuit according to an embodiment of the present invention.

As shown in FIG. 5, in a display device having a circuit according to an embodiment of the present invention, a panel 100 displaying an image includes first to third gate drivers GIC1 to GIC3 and first and second data It consists of drivers DIC1 and DIC2, and the regions B1 to B12 are divided by a circuit according to an embodiment of the present invention.

In this case, the scan rates of the first to fourth regions B1 to B4 are changed by the first gate driver GLC1, and the scan rates of the fifth to eight regions B5 to B8 are changed by the second gate driver GLC2. The scan rates of the ninth to twelfth regions B9 to B12 are changed by the third gate driver GLC3.

In addition, the scan rates of the first, fifth, and ninth regions B1, B5, and B9 are changed by the first channel DCH1 of the first data driver DIC1, and the second, sixth, and tenth regions B2, B6, B10) is the scan rate is changed by the second channel (DCH2) of the first data driver (DIC1), the third, 7, 11 areas (B3, B7, B11) is the first channel of the second data driver (DIC2) The scan rate is changed by (DCH1), and the fourth, 8, and 12 regions (B4, B8, and B12) are changed by the second channel (DCH2) of the second data driver (DIC2).

For example, in the panel 100 displaying an image at a frequency of 60 Hz, when the arrow Arr displayed in the eleventh region B11 does not move, data changes in the first to twelve regions B11. Therefore, the first to third gate drivers GLC1 to GLC3 and the first and second data drivers DIC1 and DIC2 can perform a low scan rate driving of one frame, thereby transmitting data signals and gate signals during one frame. By transmitting, the amount of power consumed during the remaining 59 frames can be reduced.

When the arrow Arr of the eleventh area B11 moves through the seventh area B7 to the sixth area B6, the third gate driver GIC3 and the second data driver DIC2 along the initial movement path ) Is switched to perform normal scan rate driving.

At this time, before the arrow Arr leaves the eleventh area B11, the general refresh rate driving is performed only in the third channel DCH3 of the third gate driver GIC3 and the second data driver DIC2. The fourth channel DCH4 of the first data driver DIC1, the second data driver DIC2, and the first gate driver GIC1 may reduce power consumption by performing low scan rate driving.

Thereafter, when the arrow Arr passes through the seventh region B7, the third channel DCH3 of the second gate driver GIC2 and the second data driver DIC2 before entering and leaving the seventh region B7 ) To perform the general scan rate driving, and the fourth channel DCH4 and the first gate driver GIC1 of the first data driver DIC1 and the second data driver DIC2 perform low scan rate driving. It can reduce consumption.

At this time, the third gate driver GIC3 is in the middle of performing the normal refresh rate driving. If the gate signal transmitted for one period after the arrow Arr enters the seventh region B7 is constant, the third gate driver GIC3 is The driver GIC3 may reduce power consumption by performing low scan rate driving again.

Thereafter, when the arrow Arr enters the sixth region B6, the general refresh rate driving is performed only in the second channel DCH2 of the second gate driver GIC2 and the first data driver DIC1. , The first channel DCH1 of the first data driver DIC1, the fourth channel DCH4 of the second data driver DIC2, and the first gate driver GIC1 perform low scan rate driving to reduce power consumption. Can.

At this time, the third channel DCH3 of the second gate driver GIC2 and the second data driver DIC2 is in the middle of performing the normal refresh rate driving, after the arrow Arr enters the sixth region B6. If the gate signal transmitted for a period from is constant, the third channel DCH3 of the second gate driver GIC2 and the second data driver DIC2 may reduce power consumption by performing low scan rate driving again.

That is, the display device according to the exemplary embodiment of the present invention detects data change of the entire panel and selects a low scan rate drive and a normal scan rate drive by data, or a region of a panel divided by a gate driver and a circuit connected thereto. By detecting the change in the image, low scan rate driving and general scan rate driving are performed.

When driving as described above, the display device is limited by performing a general refresh rate driving limited to a gate driver and a data driver connected to a driving region in which a change in the gate and data signals is detected in the panel 100 in which the driving region is divided. The effect of minimizing image quality degradation and reducing power consumption to a minimum is achieved by performing low scan rate driving outside the region.

Although described above with reference to preferred embodiments of the present invention, those skilled in the art variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You can understand that you can.

D: Data line G: Gate line
DIC: Data driver GIC: Gate driver
100: panel 111, 112: inversion
105: scan change circuit 106: level shifter

Claims (9)

A pixel area defined by first and second gate lines and a first data line;
A first thin film transistor formed in the pixel area and connected to the first gate line and the first data line;
A second thin film transistor formed in the pixel area and connected to the second gate line and the first data line;
At least one gate driver that is connected to the first and second gate lines and transmits a gate signal at a different refresh rate for each pixel area.
Including,
The first gate line is driven at a first refresh rate when there is no change in the display image,
The second gate line is driven at a second scan rate higher than the first scan rate when there is a change in the display image.
Display device.
The method of claim 1,
The gate driver is a display device including a channel output and a level shift formed with first and second inputs.
According to claim 2,
The gate driver is connected between the first and second input units, and further includes a scan change circuit that controls an output signal of the channel output unit according to the level of the input signal.
According to claim 3,
The scan change circuit is connected between the first and second input units, and a display device comprising an inversion unit for receiving the input signal.
Displaying first image data on a panel including pixel regions defined by first and second gate lines and data lines;
Receiving second image data;
Comparing the first image data and the second image data;
Separating a first display area in which the first image data and the second image data are identical, and a second display area in which the first image data and the second image data are different;
Displaying the first image data or the second image data at a first scanning rate in the first display area;
Displaying the second image data at a second scan rate higher than the first scan rate in the second display area
Including,
In the first display area, the first gate line connected to the pixel area positioned thereon is driven at the first refresh rate,
In the second display area, the second gate line connected to the pixel area positioned thereon is driven at the second refresh rate.
How to drive the display device.
delete The method of claim 5,
When the image is displayed at the first scan rate, a gate signal or a data signal is output for one frame, and then the output of the gate signal or the data signal is blocked for the remaining 59 frames, and when the image is displayed at the second scan rate, The method of driving a display device, characterized in that for outputting the gate signal or the data signal for 60 frames.
According to claim 1,
When driving at the first scan rate, the gate signal is output for one frame to the first gate line and then the output of the gate signal is blocked for the remaining 59 frames, and when driving at the second scan rate, the second gate line is 60 During the frame, the gate signal is output
Display device. The method of claim 5,
The pixel region includes a first thin film transistor connected to the first gate line and the data line, and a second thin film transistor connected to the second gate line and the data line.
How to drive the display device.

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