TWI406239B - Display apparatus, controller and driving method thereof - Google Patents

Abstract

A controller and the driving method for color sequential liquid crystal display (LCD) panel are provided. The driving method includes the steps listed below. Firstly, the LCD panel is driven at a first frame rate when a backlight is turned on. Then the LCD panel is driven at a second frame rate when a backlight is turned off, wherein the first frame rate is greater than the second frame rate. The power consumption of the LCD panel may be reduced by tuning the frame rate and backlight, so as to the usage time of a portable device with the LCD panel is extended.

Description

Display device, display device controller and driving method thereof

The present invention relates to a driving method, and more particularly to a driving method suitable for a color sequence liquid crystal display device.

At present, the color change of a general liquid crystal display is to use a white backlight to pass through a color filter to display a desired color. The color-sequential method of color rendering technology uses the light source of three primary colors of red, green and blue to quickly switch the chromaticity and mix the chromaticity to obtain the desired color. . Conventionally, a liquid crystal display using a color filter requires three sub-pixels to respectively display red, green, and blue to form a basic pixel, and a liquid crystal display using a color sequence method, each pixel can independently display red. Light, green and blue light, that is, the liquid crystal display of the color sequential method has a resolution of three times that of the conventional liquid crystal display, so the color sequence method has the advantage of high resolution. However, the color sequence technology needs to switch the R, G, and B color lights (sub-pictures) by three times the screen switching frequency, so that the human eye produces a color mixing effect. In general, the color sequence display has a frame rate of about 180 Hertz (Hz), which is about the same as a general liquid crystal display with a frame rate of 60 Hz, which is just in line with the sensing speed of the human eye's optic nerve. Since the frame rate of the color sequence display has a higher frame rate, the power consumption of the driving circuit (gate driver and source driver) is higher than that of a general liquid crystal display. For the power management of general mobile devices (such as mobile phones or notebook computers), the power consumption of the LCD panel is a big burden if the LCD panel can be lowered. Power consumption can effectively improve the use time and convenience of the mobile device.

The invention provides a driving method of a liquid crystal display, which utilizes the switching frame rate to achieve the advantages of saving power consumption and prolonging the use time of the mobile device.

The present invention provides a controller for a display device that can drive a panel by switching the frame rate according to whether the backlight is turned on or off, so that the panel can display a normal picture (such as a color picture) or a grayscale picture (such as a black and white picture). This has the advantage of reducing the power consumption of the drive circuit.

The invention provides a display device, which enters a power saving mode (the backlight is turned off), and the panel is presented in a gray scale picture, which can simultaneously reduce the power consumption of the backlight and the driving circuit, thereby prolonging the use time of the mobile device.

In view of the above, the present invention provides a driving method suitable for driving a liquid crystal panel. The driving method comprises the steps of: driving the liquid crystal panel at a first frame rate when the backlight is turned on, and driving the liquid crystal panel at a second frame rate when the backlight is turned off, and the first frame rate is greater than the first frame rate Two frame rate.

In an embodiment of the invention, the first frame rate is, for example, 180 Hz or higher, and the second frame rate is, for example, 60 Hz or lower.

In an embodiment of the present invention, in the driving method, when the backlight is turned off, the step of driving the liquid crystal panel at the second frame rate further comprises converting the color image displayed by the liquid crystal panel into a grayscale image, and the color image is The conversion formula with the grayscale picture is as follows: Y=0.299*R+0.587*G+0.114*B Where Y is the grayscale value of the grayscale picture, R is the red grayscale value of the color picture, G is the green grayscale value of the color picture, and the blue grayscale value of the B color picture. When the liquid crystal display enters the power saving mode, the screen of the liquid crystal display is converted into a grayscale picture.

To achieve the above and other objects, the present invention provides a controller for a display device including an input buffer, a switching unit, an image processing unit, a gray scale conversion unit, and a timing controller. The input buffer is used to receive color picture data. The switching unit is coupled to the input buffer for switching the transmission path of the color picture data. The image processing unit is coupled to the switching unit for processing color picture data. The grayscale conversion unit is coupled to the switching unit for converting color picture data into grayscale picture data. The timing controller is coupled to the image processing unit and the grayscale conversion unit, and drives the gate driver and the source driver according to the output of the image processing unit and the grayscale conversion unit.

Wherein, when the backlight of the display device is turned on, the timing controller drives the liquid crystal panel at a first frame rate according to the output of the image processing unit; when the backlight is turned off, the timing controller according to the grayscale image data, the second image The frame rate drives the liquid crystal panel, and the first frame rate is greater than the second frame rate.

To achieve the above and other objects, the present invention provides a display device including a backlight module, a liquid crystal panel, and a driving device. The driving device is used to drive the liquid crystal panel. When the backlight is turned on, the driving device drives the liquid crystal panel at a first frame rate; when the backlight is turned off, the driving device drives the liquid crystal panel at a second frame rate and converts one color picture displayed by the liquid crystal panel into a gray scale Picture, where the first frame rate is greater than the second frame rate.

In an embodiment of the invention, the driving device of the display device further includes a controller, a gate driver and a source driver. The controller is configured to convert the color picture and the grayscale picture and switch the first frame rate and the second frame rate. The gate driver is coupled to the controller and drives the liquid crystal panel according to the output of the controller. The source driver is coupled to the controller and drives the liquid crystal panel according to the output of the controller.

In an embodiment of the invention, the controller further includes an input buffer, a switching unit, an image processing unit, a gray scale conversion unit, and a timing controller. The input buffer is for receiving a color picture material. The switching unit is coupled to the input buffer for switching the transmission path of the color picture data. The image processing unit is coupled to the switching unit for processing color picture data. The grayscale conversion unit is coupled to the switching unit for converting color picture data into a grayscale picture material. The timing controller is coupled to the output of the image processing unit and the grayscale conversion unit, and drives the gate driver and the source driver according to the output of the image processing unit and the grayscale conversion unit.

In an embodiment of the invention, the grayscale picture comprises a black and white grayscale picture.

The invention maintains the original frame rate when the backlight is started, and reduces the frame rate after the backlight is turned off and turns the color picture into a black-and-white gray-scale picture, which not only inherits the power saving benefit of the original backlight, but also Reduce the number of times the pixels are charged, and save unnecessary power consumption on the panel side to achieve the best power saving effect. Compared with the prior art, the present invention drives the liquid crystal panel at a lower frame rate when the backlight is turned off, thereby reducing the power consumption of the driving circuit to prolong the use time of the electronic device, which is extremely heavy on the display device. The advantages.

The above and other objects, features, and advantages of the present invention will become more apparent from the description of the appended claims.

First embodiment

1 is a block diagram of a display device in accordance with a first embodiment of the present invention. Referring to FIG. 1 , the display device 100 includes a backlight module 110 , a liquid crystal panel 120 , and a driving device 130 . The driving device 130 includes a controller 131, a gate driver 132, and a source driver 133. The gate driver 132 is coupled to the controller 131 , and the source driver 133 is coupled to the controller 131 .

In detail, please continue to refer to FIG. 1 , the driving device 130 is used to drive the liquid crystal panel 120 . When the backlight of the backlight module 110 is turned on, the controller 131 of the driving device 130 causes the gate driver 132 and the source driver 133 to drive the liquid crystal panel 120 at a first frame rate; When the backlight of the group 110 is turned off, the controller 131 of the drive device 130 converts the color picture into a grayscale picture and causes the gate driver 132 and the source driver 133 to drive the liquid crystal panel 120 at the second frame rate. The first frame rate is greater than the second frame rate.

As can be seen from the above, in the display device 100 of the present embodiment, the backlight of the backlight module 110 is turned on and off, and the driving device 130 drives the liquid crystal panel 120 at two frame rates. When the backlight is turned on, the panel is driven at a normal frame rate; when the backlight is turned off, the panel is driven at a lower frame rate, and the power consumption is reduced by reducing the frame rate. Consumption. In general, when the user stops using the display device 100, the power saving mode is entered, and the backlight is turned off to save power consumption. At this time, in this embodiment, the backlight is turned off, and the frame rate is lowered and converted into gray scale. The picture has further reduced the power consumption of the drive circuit.

Further, the circuit architecture of the controller will be described. FIG. 2 is a block diagram of a controller of the display device according to the first embodiment of the present invention. Referring to FIG. 2, an input buffer 210, a switching unit 220, an image processing unit 230, a grayscale conversion unit 240, and a timing controller 250 are included. The switching unit 220 is coupled to the input buffer 210, the image processing unit 230 is coupled to the switching unit 220, the grayscale conversion unit 240 is coupled to the switching unit 220, and the timing controller 250 is coupled to the image processing unit 230 and the grayscale Conversion unit 240.

Referring to FIG. 2, when the color picture data enters the controller 131, the data is first received by the input buffer 210, and then transmitted to the switching unit 220 to switch the transmission path of the color picture data. The switching mechanism is if the backlight is When it is turned on, the color picture data is transmitted to the image processing unit 230 to process the color picture data; otherwise, if the backlight is turned off, the color picture data is transmitted to the gray level conversion unit 240, and the color picture data is converted into grayscale picture data. . Finally, the timing controller 250 transmits the output of the image processing unit 230 at the first frame rate or the output of the grayscale conversion unit 240 to the gate driver 132 and the source driver 133 at the second frame rate, and the gate driver The 132 and source drivers 133 can drive the liquid crystal panel 120 according to the output of the timing controller 250. The first frame rate (e.g., 180 Hz) is greater than the second frame rate (e.g., 60 Hz).

The gray scale conversion unit 240 described above converts color picture data and gray scale painting The conversion formula of the surface data is as follows: Y=0.299*R+0.587*G+0.114*B where Y is the grayscale value of the grayscale picture data, R is the red grayscale value of the color picture data, and G is the color picture data. The green grayscale value, B is the blue grayscale value of the color picture data. It should be noted that the conversion formula of the above-mentioned color picture and gray scale picture is only an example of the embodiment, and the present invention is not limited to the above conversion formula.

It can be seen from the above that the controller 131 of the display device 100 of the present invention can drive the panel at different frame rates according to the opening or closing of the backlight, so that the panel can be used at a first frame rate (for example, 180 Hz) in general use. To display a normal picture (eg, a color picture); to display a grayscale picture (eg, a black and white grayscale picture) at a second frame rate (eg, 60 Hz) in the power saving mode, to achieve the advantage of reducing the power consumption of the display device 100 .

Second embodiment

3 is a flow chart showing a driving method of a liquid crystal display according to a second embodiment of the present invention. Referring to FIG. 3, the driving method is as follows. In step S101, it is detected whether the backlight of the display is turned on. If the backlight is turned on, the process goes to step S102; otherwise, the process goes to step S104. If the backlight is turned on, the received color picture material is processed in step S102, and the liquid crystal panel is driven at the first frame rate in step S103. If the backlight is turned off, in step S104, the received color picture data is converted into grayscale picture material, and in step S105, the liquid crystal panel is driven at the second frame rate. Next, proceeding to step S106, the screen is displayed in accordance with the corresponding frame rate.

It should be noted that in the above step S104, the conversion formula of the color picture and the gray scale picture can be as shown in the formula of the first embodiment. For the rest of the driving method, please refer to the description of the above embodiment. Add a few words.

It can be seen from the above that the driving method of the invention can detect the opening or not of the display backlight to further switch the frame rate, thereby achieving the effect of saving power consumption, thereby prolonging the use time of the mobile device.

In combination with the first embodiment of FIG. 1 and FIG. 2 and the second embodiment of FIG. 3, the driving method of the embodiment can be summarized as follows: when the backlight of the backlight module 110 is turned on, the normal frame rate is A normal picture (for example, a color picture) is used to display the picture; when the backlight of the backlight module 110 is turned off, the picture is displayed at a lower frame rate, and the picture is converted into a black and white grayscale picture. Thereby, the power consumption of the backlight and the driving circuit (for example, the source driver and the gate driver) is simultaneously reduced.

In view of the above, the driving method of the present invention is applicable to a color sequence liquid crystal display, and can drive the liquid crystal panel in a manner of reducing the frame rate when the liquid crystal display enters the power saving mode, that is, when the backlight is turned off. Reducing the frame rate can reduce the amount of power used, thereby extending the use time, which is an extremely important advantage for the display device.

Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100‧‧‧ display device

110‧‧‧Backlight module

120‧‧‧LCD panel

130‧‧‧ drive

131‧‧‧ Controller

132‧‧‧gate driver

133‧‧‧Source Driver

210‧‧‧Input buffer

220‧‧‧Switch unit

230‧‧‧Image Processing Unit

240‧‧‧ Grayscale conversion unit

250‧‧‧ timing controller

S101~S106‧‧‧Steps

1 is a block diagram of a display device in accordance with a first embodiment of the present invention.

2 is a block diagram of a controller of a display device according to a first embodiment of the present invention.

3 is a flow chart showing a driving method of a liquid crystal display according to a second embodiment of the present invention.

S101~S106‧‧‧Steps

Claims (17)

A driving method for driving a liquid crystal panel, the driving method comprising: driving the liquid crystal panel at a first frame rate when a backlight is turned on; and at a second frame rate when the backlight is turned off Driving the liquid crystal panel and converting one of the color images displayed by the liquid crystal panel into a grayscale image; wherein the first frame rate is greater than the second frame rate. The driving method of claim 1, wherein the first frame rate is 180 Hz. The driving method of claim 1, wherein the second frame rate is 60 Hz. The driving method of claim 1, wherein the color picture and the grayscale picture are converted as follows: Y=0.299*R+0.587*G+0.114*B, where Y is the gray of the grayscale picture The order value, R is the red grayscale value of the color picture, G is the green grayscale value of the color picture, and B is the blue grayscale value of the color picture. The driving method of claim 1, wherein the grayscale picture comprises a black and white grayscale picture. A controller for a display device is adapted to drive a liquid crystal panel, the controller comprising: an input buffer for receiving a color picture material; a switching unit coupled to the input buffer for switching a transmission path of the color picture data; an image processing unit coupled to the switching unit for processing the color picture data; a gray scale conversion unit, coupled And the switching unit is configured to convert the color picture data into a grayscale image data; and a timing controller coupled to the output of the image processing unit and the grayscale conversion unit, and according to the image processing unit An output of the gray scale conversion unit drives a gate driver and a source driver; wherein when a backlight of the display device is turned on, the timing controller uses a first frame rate according to an output of the image processing unit Driving the liquid crystal panel; when the backlight is turned off, the timing controller drives the liquid crystal panel at a second frame rate according to the grayscale image data, wherein the first frame rate is greater than the second frame rate. The controller of claim 6, wherein the first frame rate is 180 Hz. The controller of claim 6, wherein the second frame rate is 60 Hz. The controller of claim 6, wherein the grayscale conversion unit converts the color picture data and the grayscale picture data into a conversion formula as follows: Y=0.299*R+0.587*G+0.114*B Y is the grayscale value of the grayscale picture data, R is the red grayscale value of the color picture data, and G is the green grayscale of the color picture data. Value, B is the blue grayscale value of the color picture material. The controller of claim 6, wherein the grayscale picture material comprises a black and white grayscale picture material. A display device includes: a backlight module having a backlight; a liquid crystal panel; and a driving device for driving the liquid crystal panel; wherein, when the backlight is turned on, the driving device is in a first frame Driving the liquid crystal panel at a rate; when the backlight is turned off, the driving device drives the liquid crystal panel at a second frame rate, and converts a color image displayed by the liquid crystal panel into a grayscale image, wherein the first frame The rate is greater than the second frame rate. The display device of claim 11, wherein the driving device comprises: a controller for converting the color picture and the grayscale picture and switching the first frame rate and the second frame rate; a gate driver coupled to the controller, driving the liquid crystal panel according to an output of the controller; and a source driver coupled to the controller to drive the liquid crystal panel according to an output of the controller. The display device of claim 12, wherein the controller comprises: an input buffer for receiving a color picture data; and a switching unit coupled to the input buffer for switching the color picture Data transmission path; An image processing unit is coupled to the switching unit for processing the color picture data; a gray level conversion unit coupled to the switching unit for converting the color picture data into a grayscale image data; The sequence controller is coupled to the image processing unit and the gray scale conversion unit, and drives the gate driver and the source driver according to the output of the image processing unit and the gray scale conversion unit. The display device of claim 13, wherein the grayscale conversion unit converts the color picture data and the grayscale picture data into a conversion formula as follows: Y=0.299*R+0.587*G+0.114*B Y is the grayscale value of the grayscale picture data, R is the red grayscale value of the color picture data, G is the green grayscale value of the color picture data, and B is the blue grayscale value of the color picture data. The display device of claim 11, wherein the first frame rate is 180 Hz. The display device of claim 11, wherein the second frame rate is 60 Hz. The display device of claim 11, wherein the grayscale picture comprises a black and white grayscale picture.