TWI726602B - Display device driving method - Google Patents

Abstract

The present disclosure relates to a display device driving method including the following steps: A controller performs the data writing of a pixel matrix circuit during a data charging period. Providing an enable signal to a backlight unit.. At intervals of a setting time, if the controller does not receive a data signal, the controller provide the enable signal again to drives the backlight unit. At a next data charging period, the controller provide the data signal to perform data writing.

Description

Display device driving method

The present disclosure relates to a method for driving a display device, particularly a technology for driving a pixel matrix and a backlight unit in the display device.

Flat display devices have become the mainstream of various display devices. For example, household televisions, personal computers and laptop computer monitors, mobile phones and digital cameras, etc., are all products that use a large number of flat display devices. The conventional display device mainly includes a backlight unit that generates a backlight and a display panel that receives the backlight and generates an image. When the pixel matrix in the display panel is driven, the backlight unit must provide corresponding light so that the display panel can present a corresponding image. Therefore, the control of the pixel matrix and the backlight unit will affect the quality of the picture presented by the display panel.

One aspect of the present disclosure is a method for driving a display device, which includes the following steps: the controller writes data into the pixel matrix during the data charging period. The controller provides an enabling signal to drive the backlight unit. Whenever the interval time elapses and the controller does not receive the data signal, the controller again provides an enabling signal to drive the backlight unit. During the charging period of the next frame of data, the controller provides a data signal to write data into the pixel matrix.

According to this, after the controller finishes writing data to the pixel matrix, the backlight unit will periodically generate light. Therefore, even if the update frequency of the pixel matrix dynamically corresponds to the time for the processing unit to calculate and draw the data signal, The picture presented by the display device can still maintain a smooth and stable quality.

Hereinafter, a plurality of embodiments of the present invention will be disclosed in drawings. For clear description, many practical details will be described in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is to say, in some embodiments of the present invention, these practical details are unnecessary. In addition, in order to simplify the drawings, some conventionally used structures and elements will be shown in a simple schematic manner in the drawings.

In this text, when an element is referred to as “connected” or “coupled”, it can be referred to as “electrically connected” or “electrically coupled”. "Connected" or "coupled" can also be used to mean that two or more components cooperate or interact with each other. In addition, although terms such as “first”, “second”, etc. are used herein to describe different elements, the terms are only used to distinguish elements or operations described in the same technical terms. Unless the context clearly indicates, the terms do not specifically refer to or imply order or sequence, nor are they used to limit the present invention.

The present disclosure relates to a method for driving a display device, which is applied to the display device 100. Please refer to FIG. 1, the display device 100 includes a display panel 110, a processing unit 120 (for example, a system board, a motherboard, or a graphics processor), and a backlight unit 130. The display panel 110 includes a controller TCON, a scan driver 112, a data driver 113, and a pixel matrix 111. The controller TCON is used to receive the image signal Vdata from the processing unit 120, and control the scan driver 112 and the data driver 113 according to the image signal Vdata to drive a plurality of pixel units A in the pixel matrix 111. The controller TCON also controls the backlight unit 130 through the control signal Sb. When the control signal Sb is at the enable level, the control signal Sb is the enable signal to drive the backlight unit. When the control signal Sb is the disable level, the control signal Sb is the disable signal to turn off the backlight unit. In some embodiments, the display panel 110 may be a liquid crystal display, but the disclosure is not limited to this.

In this embodiment, the display device 100 adopts the synchronization technology of "V-sync" or "G-sync" or "Free-sync". That is, the processing unit 120 will provide the data signal Vdata to the display panel 110 only after the complete picture is drawn. The “complete picture” refers to the voltage value corresponding to each pixel unit A on the pixel matrix 111 calculated by the processing unit 120. Through the synchronization technology, the display panel 110 dynamically adjusts the refresh rate of the pixel matrix 111 according to the drawing speed of the processing unit 120. For example, if the processing unit 120 calculates the data signal Vdata in 30 milliseconds, the period during which the display panel 110 displays the corresponding screen is 30 milliseconds. Similarly, if the processing unit 120 spends 11 milliseconds when computing the next frame, the cycle will become 11 milliseconds. Since those in the field can understand the synchronization details of "V-sync" and "G-sync" and "Free-sync", I will not repeat them here.

The content of the present disclosure is to adjust the driving mode of the backlight unit 130 in the display device 100 for the synchronization processing of the data signal Vdata to ensure the display quality. In some embodiments, the backlight unit 130 is provided with a plurality of backlight elements (such as light emitting diodes). Please refer to FIGS. 2 and 3A. FIG. 2 is a schematic diagram of the driving method of some embodiments of the disclosure. FIG. 3A is a schematic diagram of signal waveforms in the display device 100. For the convenience of description, the time during which the display device 100 displays one screen is called the "frame period", such as F1, F2, F3, F4, and F5 as indicated by the 3A icon.

As shown in Figure 2, the driving method includes steps S201 to S207. In step S201, the controller TCON provides the data signal Vdata to the pixel matrix 111 of the display panel 110 to write data to the pixel matrix 111 (ie, charge to a specific voltage value). This time is the "data charging period F11". In some embodiments, the display panel 110 charges the pixel matrix 111 through the scan driver 112 and the data driver 113. As shown in FIG. 1, the scan driver 112 is used to sequentially turn on a plurality of pixel units in each row of the pixel matrix 111. For example, through the scan line SL, the scan signal Vg1 is transmitted to the gates of the first transistor switches T11 to T1n of the first pixel unit in the first row. After the transistor switch of the pixel unit A is turned on, the data driver 113 is used to transmit the voltage value corresponding to the data signal Vdata through the data line DL to charge the pixel unit (ie, write data). For example, the data voltages Vd1~Vdn are transmitted to the first pixel unit of the first row through the data line DL. Similarly, after the first pixel unit in the first row is charged, the scan driver 112 turns on the second transistor switch of the second pixel unit in the second row in the pixel matrix 111. The data driver 113 charges the second pixel units (ie, writes data) through the data line DL. By analogy, the charging of all pixel units A is completed in sequence.

In some embodiments, before the controller TCON receives the data signal Vdata, the controller TCON pre-charges the pixel unit A to a predetermined voltage value (for example, a voltage corresponding to a gray scale value of 100). According to this, when the subsequent display panel 110 receives the data signal Vdata, the pixel matrix 111 can be charged to the corresponding voltage quickly without the need to start recharging from zero voltage. The value of the preset voltage value can be adjusted arbitrarily.

In addition, as shown in Figure 3A, in some embodiments, the controller TCON will set the control signal Sb to be disabled during the data charging period F11 The level (disable signal) is used to control the backlight unit 130 to remain in the disabled state. In other embodiments, during the charging period F11, the controller TCON does not transmit the control signal Sb (the voltage is zero, which is equivalent to not transmitting) to the backlight unit 130, so the backlight unit 130 does not generate light.

In step S202, after the data charging period F11 (that is, after the display panel 110 charges the pixel matrix 111 to the preset voltage value or the data voltage value), the sustain period F12 will be entered. During the maintenance period F12, the controller TCON will transmit an enable signal (ie, set the control signal Sb to the enable level) to the backlight unit 130 to drive the backlight unit 130 so that the backlight unit 130 generates light for a predetermined period of time ta( That is, it emits light for the first time).

Next, in step S203, the controller TCON determines whether the data signal Vdata has been received. In step S204, if the controller TCON does not receive the data signal Vdata, the controller TCON starts timing and records the elapsed time of the backlight unit 130 after the previous light emission. In step S205, the controller TCON determines whether a preset interval time tb has elapsed since the previous light emission of the backlight unit 130. If the interval time tb has not been exceeded, the controller TCON will keep timing.

The length of the interval time tb does not exceed the update time of the display panel 110 (pixel matrix 111). For example, if the update frequency of the pixel matrix 111 is 240 Hz and the update time is 4.17 milliseconds, the longest interval tb can be set to 4.16 milliseconds. In some embodiments, the length of the interval tb is close to half of the highest update frequency.

If the controller TCON does not receive the data signal Vdata, and The elapsed time (ie, the time after the previous drive) of the light unit 130 has reached the interval time tb after the previous light emission of the light unit 130, then in step S206, the controller TCON will provide the enable signal again (the enable signal of the control signal Sb) Level) to drive the backlight unit 130 to make the backlight unit 130 generate light, and the duration is also the predetermined time ta (that is, the second light emission). In addition, the controller S206 will clear the timing record and re-determine whether the data signal Vdata is received.

According to this, the controller TCON will drive the backlight unit 130 again every time the interval time tb has elapsed and the data signal Vdata is not received, so that the backlight unit 130 generates light again. In some embodiments, the length of the interval tb is equal to the length of the charging period F11.

In step S207, if the controller TCON receives the data signal Vdata from the processing unit 120, the controller TCON will drive the pixel matrix 111 through the scan driver 112 and the data driver 113 according to the data signal Vdata, so that the pixel matrix 111 Each pixel unit is charged to the corresponding voltage. In step S208, when entering the next frame of data charging period, the controller TCON will perform the same steps as the aforementioned steps S201 to S206, and again provide the data signal Vdata received from the processing unit 120 to the pixel matrix 111 To write data.

Through the aforementioned driving method, even if the update frequency of the display panel 110 (pixel matrix 111) is dynamically changed, the controller TCON will periodically drive the backlight unit 130 during the maintenance period F12 to ensure uniform brightness of the display screen. The flicker may be caused by the inconsistent length of the sustain period F12 of each frame period F1.

In addition, in some embodiments, in step S204, the controller TCON is also used to record the length of time elapsed after the data charging period F11 ends. If the controller TCON determines that a preset update time (such as the duration of the maintenance period F12 shown in Figure 1) has passed after the end of the data charging period F11, even if the processing unit 120 has not yet provided the data signal Vdata, the controller TCON The data signal Vdata will still be actively obtained from the processing unit 120. Accordingly, it is possible to avoid the problem that the sustain period F12 is too long and causes the picture to be discontinuous.

In some embodiments, the time length of the data charging period F11 corresponds to the upper limit of the update frequency of the display panel 110. That is, the time length of the charging period F11 can be equal to (or close to) the shortest time for the display panel 110 to complete charging. For example, if the maximum update frequency of the display panel 110 (pixel matrix 111) is 240 Hz, the charging period F11 is 4.16 milliseconds.

In some embodiments, the length of the update time (equivalent to F12 shown in Figure 3A) corresponds to the lower limit of the update frequency of the display panel 110 (pixel matrix 111). That is, the total time of the charging period F11 and the update time may be equal to (or close to) the lower limit preset by the display panel 110. For example, if the maximum update frequency of the display panel 110 (pixel matrix 111) is 30 Hz (ie, 33.33 milliseconds per cycle), and the charging period F11 is 4.16 milliseconds, the update time (ie, the upper limit of the maintenance period F12) is 29.17 milliseconds.

As shown in Figure 3A, in the frame period F2, since the data charging period F21 ends and the backlight unit 130 is driven for the first time, the controller TCON receives the data signal Vdata, so the frame period F2 ends without The backlight unit 130 will be driven a second time. Similarly, in the frame period F3, after the data charging period F31 ends, the backlight unit 130 is first driven twice in the sustain period F32. Then, after the backlight unit 130 is driven for the second time, the controller TCON receives the data signal Vdata after the maintenance time tc has elapsed. Since the sustain time tc has not reached the length of the interval time tb, the frame period F3 ends, and there will be no third light emission. Similarly, the frame period F4 has a data charging period F41 and a sustain period F42, and the frame period F5 has a data charging period F51.

In the foregoing embodiment, when the backlight unit 130 is driven, the backlight light sources corresponding to all the pixel units A are generated at the same time, but the present disclosure is not limited to this. Please refer to FIG. 3B, which is a schematic diagram of signal waveforms according to another embodiment of the present disclosure. When the controller TCON drives the backlight unit 130, not all the backlight elements on the backlight unit 130 are driven at the same time. Please refer to FIG. 4 together. In some embodiments, multiple backlight elements (such as light-emitting diodes, positions corresponding to each pixel unit A) on the backlight unit 130 correspond to the pixel unit A is arranged in rows so as to be divided into multiple rows of backlight areas 130a to 130n.

In the process of the controller TCON driving the backlight unit 130 (ie, time ta), the controller TCON first drives the first backlight element corresponding to the first pixel unit in the first row of the backlight unit 130 (ie, Figure 4). The shown first backlight area 130a). Then, the second backlight element of the backlight unit 130 corresponding to the second pixel unit located in the second row of the pixel matrix 111 (ie, the second backlight area 130b shown in FIG. 4) is driven. By analogy, the controller TCON only drives a single row of backlight areas at a time until all the backlight areas have completed lighting (as shown in Figures 3B and 4, the enabling period of the control signal Sb in Figure 3B can be subdivided into the fourth The sequential enabling process of 130a～130n in the figure).

In addition, as shown in FIG. 3B, since the backlight unit 130 is driven in separate rows, during the charging period F11, the controller TCON can control the scan driver 112 and the data driver 113 to charge the pixel matrix 111 while simultaneously transmitting and enabling accurate The bit control signal Sb is sent to the backlight unit 130 to sequentially drive all the backlight elements in the same row in the backlight unit 130 to generate the corresponding backlight light row by row.

The various elements, method steps, or technical features in the foregoing embodiments can be combined with each other, and are not limited to the order of description or presentation of the figures in the present disclosure.

Although the content of the present invention has been disclosed in the above embodiments, it is not intended to limit the content of the present invention. Anyone who is familiar with the art can make various changes and modifications without departing from the spirit and scope of the content of the present invention. Therefore, the present invention The scope of protection of the content shall be subject to the scope of the attached patent application.

100: display device 110: display panel 111: Pixel Matrix

112: Scan drive

113: Data Drive

120: processing unit

130: Backlight unit

SL: scan line

DL: Data line

Vdata: data signal

Sb: control signal

Vg1: Scan signal

Vd1~Vdn: data voltage

A: Pixel unit

F1: frame period

F2: frame period

F3: frame period

F4: frame period

F5: frame period

F11: During charging

F12: Maintenance period

F21: During charging

F31: During charging

F32: Maintenance period

F41: During charging

F42: Maintenance period

F51: During charging

130a~130n: Backlight area TCON: Controller S201~S208: steps

FIG. 1 is a schematic diagram of a display device according to some embodiments of the present disclosure. FIG. 2 is a flowchart of steps of a driving method of a display device according to some embodiments of the present disclosure. FIG. 3A is a signal waveform diagram of a driving method of a display device according to some embodiments of the present disclosure. FIG. 3B is a signal waveform diagram of a display device driving method according to some embodiments of the present disclosure. FIG. 4 is a schematic diagram of a backlight unit and a driving method according to some embodiments of the present disclosure.

Domestic deposit information (please note in the order of deposit institution, date and number) no Foreign hosting information (please note in the order of hosting country, institution, date, and number) no

S201~S208: steps

Claims (10)

A method for driving a display device includes: during a data charging period, a controller to write data to a pixel matrix; during a maintenance period, the controller provides a consistent energy signal to drive a backlight unit; In the interval time and the controller does not receive a data signal, the controller again provides the enable signal to drive the backlight unit; and during the next frame of data charging period, the controller provides the data signal to the pixel matrix Write data. The driving method of the display device according to claim 1, further comprising: recording the elapsed time after the backlight unit was previously driven. The display device driving method according to claim 1, further comprising: providing a disable signal to turn off the backlight unit during the charging period of the data. The display device driving method according to claim 1, further comprising: after the data charging period ends, if the controller does not receive the data signal during an update period, the controller actively obtains the data signal from a display unit Data signal. The display device driving method according to claim 4, wherein the time length of the update period corresponds to a lower limit of the update frequency of the pixel matrix. The display device driving method according to claim 1, wherein the length of the interval time is equal to the length of the data charging period. The display device driving method according to claim 6, wherein the length of the data charging period corresponds to an upper limit value of an update frequency of the pixel matrix. The display device driving method according to claim 1, wherein the method of driving the backlight unit includes: a controller driving a plurality of first pixel units in the backlight unit corresponding to the plurality of first pixel units located in the first row of the pixel matrix A first backlight element; and the controller drives a plurality of second backlight elements in the backlight unit corresponding to the plurality of second pixel units located in the second row of the pixel matrix. The display device driving method according to claim 1, wherein the method for the controller to provide the data signal to write data to the pixel matrix includes: turning on the first row of the pixel matrix through a scan driver complex A plurality of first transistor switches of a plurality of first pixel units; through a data driver, the first pixel units are charged; through the scan driver, a plurality of first pixel units in the second row of the pixel matrix are turned on A plurality of second transistor switches of the second pixel unit; and charging the second pixel units through the data driver. The display device driving method according to claim 1, further comprising: sequentially driving a plurality of backlight elements in the same row in the backlight unit during the data charging period.

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