CN100392478C - Resolution-changing circuit device for liquid crystal display panel - Google Patents

Abstract

A resolution changing circuit device for a liquid crystal display panel includes a pixel circuit, a gate driving circuit and a source driving circuit. The gate driving circuit and the pixel circuit are electrically connected by a plurality of gate lines, and a gate control signal is used to determine whether an original gate driving signal or a target gate driving signal is applied to the gate line as a gate driving signal. Among them, a switch circuit is used to control which of the original gate driving signal and the target gate driving signal can be output to the pixel circuit.

Description

Circuit device for changing resolution of liquid crystal display panel

technical field

The invention relates to a technology for changing resolution of a display panel, in particular to a circuit device for changing resolution of a liquid crystal display panel.

Background technique

A still image can basically be regarded as a complex combination of many bright and dark cells. In the photo printing process, the use of fine grains of silver nitrate can provide the difference between light and dark needed to reproduce the image. When a picture is printed using photoengraving, it can be clearly seen that it is composed of many small printing dots. Each bright or dark small area can simply be called a pixel (Pixel). When all the pixels are organized together, they constitute the visual information of the scene picture. If all these pixels can be re-emitted and recombined, with appropriate brightness Attached to the appropriate position of the screen, the original image screen can be reproduced. The quality of pixels can be expressed by the resolution of the image (Resolution), also known as the definition (Definition), its size depends on the number of pixels that can be displayed, usually in dots per inch to calculate. If there are many small pixels in a frame (Frame), then the image will have better picture details. Therefore, the more pixels contained in a picture of the same size, the finer the details of the reproduced picture information can be provided.

Flat Panel Displays (Flat Panel Displays), such as Liquid Crystal Displays and Plasma Displays, because they have more detailed display capabilities and lower energy consumption, so it is considered a replacement for cathode ray tube displays. Now, most of the laptop and notebook products use liquid crystal displays as display screens. Although the price is relatively expensive, there are not a few desktop computers that use liquid crystal displays. Current LCD panels (LCD Panels) adopt Active Matrix Design (ActiveMatrix Design), usually using thin film transistor technology (Thin Film Transistor Technology, TFT Technology). This technology is designed in a one-to-one manner, with one thin film transistor corresponding to one pixel. The advantage of using an active matrix design is that the pixels can be turned on or off quickly because only a small current is required to pass through the horizontal and vertical grids. A thin film liquid crystal display (TFT-LCD) contains a liquid crystal layer with optical anisotropy. The liquid crystal layer controls and adjusts the infiltration amount of the light source through the difference of the provided electric field intensity, and thus obtains pixels corresponding to the picture information.

The LCD screen contains an interface circuit (Interface Circuit), which can convert the analog video signal input obtained by the host system (Host System) into a corresponding digital video signal, thereby driving each pixel on the LCD panel. Because the resolution of the liquid crystal display screen is determined according to the number of pixels that can be displayed in the active display area (Active Display Area) composed of the active matrix. Therefore, the liquid crystal display screen is forced to be operated in a single display mode. For example, when displaying an image with a resolution of Video Graphics Array (VGA), it is necessary to have 640*480 pixels in the active display area. One of the video graphics arrays (Quarter Video Graphics Array, QVGA) just needs 1/4 times of VGA, which means 320*240 pixels. If it is a super video graphics array (Super Video Graphics Array, SVGA), it needs to have 800*600 pixels, and if it is an extended graphics array (Extended Graphics Array, XGA), it is 1024*768 pixels. There are so many types of resolutions, so in actual use, a single display panel can have the function of displaying different resolutions is what consumers need, and it is especially hoped that this liquid crystal display panel can switch the video graphics array that is often used (VGA) and Quarter Video Graphics Array (QVGA) resolutions.

Contents of the invention

The driving circuits used in the liquid crystal display panel respectively include a source driver circuit (Source Driver Circuit) and a gate driver circuit (Gate Driver Circuit). Among them, the source driver circuit is responsible for sampling and outputting image data, so it is also called a data driver circuit (Data Driver Circuit) or a row driver circuit (Column Driver Circuit). The gate drive circuit uses each horizontal line (Horizontal Line) to scan the liquid crystal display. That is, the source driving circuit applies an image data signal to the source line (Source Line) of the thin film transistor, and the gate driving circuit applies a gate driving signal to the gate line (Gate Line).

The object of the present invention is to provide a resolution changing circuit device of a liquid crystal display panel, which is suitable for changing an original resolution to a target resolution according to a grid control signal. The device includes: a pixel circuit for A gate drive signal and a source drive signal generate an image; a gate drive circuit is coupled to the pixel circuit with a plurality of gate lines for determining an original gate drive according to the gate control signal One of the gate driving signal and a target gate driving signal is the gate driving signal, and the gate driving circuit includes: a plurality of shift registers for outputting the gate driving signal; and a plurality of register switches for outputting the gate driving signal according to The gate control signal switches between the following two conditions, and selects to output the original gate drive signal or the target gate drive signal; A. Turn on the electrical property between the shift register and the subsequent shift register channel; B. turn on the electrical channel between the shift register and the second-stage shift register; wherein, when the register switch is switched to B, the gate control signal needs to be input to the first shift register at the same time The input terminals of the bit register and the second shift register, and a source driving circuit are coupled to the pixel circuit through a plurality of source lines, so as to output the source driving signal according to a source control signal.

The main purpose of the present invention is to provide a circuit device in which the resolution of a liquid crystal display panel can be changed. This circuit device makes the gate drive circuit output a target gate drive signal according to a gate control signal and a switch circuit, so as to realize the The resolution of the liquid crystal display panel is changed from the original resolution to the target resolution, and an image whose resolution is the target resolution is displayed. In addition, since the circuit device is arranged inside the liquid crystal display panel, it does not increase the space required by the liquid crystal display, and the components used are simple and small in size, so the required cost is low and power consumption can be reduced.

Another circuit device for changing the resolution of a liquid crystal display panel according to the present invention is suitable for changing an original resolution to a target resolution according to a grid control signal. A gate drive signal and a source drive signal generate an image; a gate drive circuit is coupled to the pixel circuit with a plurality of gate lines for determining an original gate drive signal according to the gate control signal One of the gate drive signal and a target gate drive signal is the gate drive signal, and the gate drive circuit includes: a plurality of shift registers for outputting the gate drive signal; a plurality of register switches for outputting the gate drive signal according to the gate Pole control signal, switch between the following two conditions, select to output the original gate drive signal or the target gate drive signal; A. Turn on the electrical channel between the shift register and the next stage shift register; B. Turn on the electrical channel between the first shift register and the second shift register and the electrical channel between the second shift register and the rear secondary shift register in the subsequent shift register; and a plurality of gate line switches, which are used to turn on the shift register, the subsequent shift register and the electrical channel of the pixel circuit when the register switch is switched to A, and when the register switch is switched to When reaching B, turn on the electrical channel between the first shift register, the second shift register and the pixel circuit, and the second shift register and the second shift register in the subsequent shift register The electrical channel between the register and the pixel circuit; wherein, when the register switch is switched to B, the gate lines need to be connected in pairs in sequence, and a source driving circuit, coupled with multiple source lines to the pixel circuit to output the source driving signal according to a source control signal.

In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is specifically cited below and described in detail with reference to the accompanying drawings.

Description of drawings

FIG. 1 shows a block diagram of a resolution changing circuit device according to a preferred embodiment of the present invention.

FIG. 2A shows a schematic circuit diagram of a gate drive circuit according to a first preferred embodiment of the present invention at an original resolution;

FIG. 2B shows a schematic circuit diagram of a gate drive circuit according to a first preferred embodiment of the present invention at a target resolution;

FIG. 3A shows a schematic circuit diagram of a gate drive circuit according to a second preferred embodiment of the present invention at an original resolution;

3B shows a schematic circuit diagram of a gate drive circuit according to a second preferred embodiment of the present invention at a target resolution;

FIG. 4A shows a schematic circuit diagram of a gate drive circuit according to a third preferred embodiment of the present invention at an original resolution; and

FIG. 4B shows a schematic circuit diagram of a gate driving circuit according to a third preferred embodiment of the present invention at a target resolution.

Explanation of reference numbers

103: Liquid crystal display panel

106: Gate drive circuit

109: Source drive circuit

112: Source control signal

114: Gate drive signal

116: Control logic circuit

206～218: shift register

221～230: gate line

233～251: register switch

306～318: shift register

321～330: gate line

333～351: register switch

354～363: Gate line switch

406~421: shift register

424～436: gate lines

439~448: register switch

451～463: Gate line switch

Detailed ways

Please refer to FIG. 1 , which shows a block diagram of a resolution changing circuit device according to a preferred embodiment of the present invention. This circuit device includes a pixel circuit 103, a gate driving circuit 106, and a source driving circuit 109. with a control logic circuit 116 . Wherein, the pixel circuit 103 generates an image according to the received gate driving signal and source driving signal. The gate drive circuit 106 uses a plurality of gate lines to connect to the pixel circuit 103, and decides whether to output the original gate drive signal or the target gate drive signal according to a gate control signal 114 as the gate of the input pixel circuit 103. pole drive signal. The source driving circuit 109 is connected to the pixel circuit 103 by a plurality of source lines, and outputs a source driving signal according to a source control signal 112 . The control logic circuit 116 is used to provide the gate control signal 114 and the source control signal 112. Although the control logic circuit 116 is not included in the present invention, those skilled in the art will know that this circuit can use an application-specific integrated circuit (Application Specific Integrated Circuit), this kind of integrated circuit can be designed and manufactured according to different needs and functions of customers and meet customer requirements.

Wherein, the gate driving circuit 106 uses switching of the switch circuit to output the original gate driving signal and the target gate driving signal. Originally, one gate line corresponds to one pixel. Therefore, when two gate lines transmit the same gate driving signal, the corresponding two pixels can be ignored and regarded as one pixel in image reproduction. And when two gate lines transmit the same gate driving signal, the resolution presented by the entire liquid crystal display panel will be 1/2 of the original resolution.

Next, please refer to FIG. 2A and FIG. 2B , which show a schematic circuit diagram of the gate driving circuit according to the first preferred embodiment of the present invention under the original resolution and the target resolution. The driving circuit of this embodiment includes a plurality of shift registers 206 - 218 , a plurality of gate lines 221 - 230 and a plurality of register switches 233 - 251 . Wherein, the plurality of shift registers 206 - 218 output gate driving signals through the plurality of gate lines 221 - 230 . The plurality of register switches 233 - 251 can switch between the two states of FIG. 2B and FIG. 2A according to the gate control signal, and select to output either the original gate driving signal or the target gate driving signal. In FIG. 2B , the register switches 233 - 235 will turn on the electrical channels between the shift registers 206 - 218 and the shift registers of the next stage. In FIG. 2A , the channels between the shift registers 206 - 218 and the last two stages of shift registers are turned on. In FIG. 2A , the gate control signal 114 is also input to the input terminals of the shift register 206 and the shift register 209 at the same time.

Use the register switch to conduct the electrical channel between the output terminal of a certain shift register and the input terminal of the subsequent stage shift register, or connect the output terminal of this shift register to the shift register of the subsequent stage The electrical path between the input terminals of the register is turned on. For example, if the shift register is the shift register 206, then the register switch 223 will determine whether to conduct the electrical channel between the shift register 206 and the shift register 209 according to the gate control signal 114. Alternatively, the electrical channel between the shift register 206 and the shift register 212 is to be turned on, and the operations of the switches of each register can be deduced by analogy.

In the above example, when the electrical channel between the shift register 206 and the shift register 209 is turned on, the electrical channel between the shift register 209 and the shift register 212 is turned on, and so on, that is, in the figure In the case of 2B, the number of identifiable pixels that can be displayed by each gate line respectively outputting the gate driving signal to the liquid crystal display panel is assumed to be a target number. On the other hand, when the electrical channel between the shift register 206 and the shift register 212 is turned on, the electrical channel between the shift register 209 and the shift register 215 is turned on, and so on, that is, in FIG. 2A In the case of , the number of identifiable pixels that can be displayed by each gate line respectively outputting the gate driving signal to the liquid crystal display panel is half of the above-mentioned target number, assuming an original number, Under this assumption, since the original number of gate lines is 1/2 times the target number, it can be seen that the original resolution is 1/2 times the target resolution, thus the purpose of changing the resolution can be achieved.

Next, please refer to FIG. 3A and FIG. 3B , which show a schematic circuit diagram of a gate driving circuit according to a second preferred embodiment of the present invention under the original resolution and the target resolution. The driving circuit of this embodiment includes a plurality of shift registers 306-318, a plurality of gate lines 321-330, a plurality of register switches 333-351 and a plurality of gate line switches 354-363. The preferred embodiment uses a plurality of gate line switches 354-363 arranged on a plurality of gate lines 321-330, and uses practical examples to illustrate the operation modes of these gate line switches 354-363. When the register switch 333 When ~351 is switched to the position of FIG. 3B, the electrical channel between the shift register 306 and the shift register 309 is turned on, and the gate line switch 354 will switch the shift register 306, the shift register 309 and the pixel circuit The electrical channels between 103 are turned on. In simple terms, when the register switches 333-351 are switched to the positions shown in FIG. Conduction of the electrical channel between. In addition, when the register switch is switched to the position shown in FIG. 3A , for example, when the electrical channel between the shift register 306 and the shift register 312 is turned on, the gate line switch 354 will switch the shift register 306, the shift register The electrical channel between 312 and the pixel circuit 103 is also conducted through the gate line 321, that is to say, in the situation of FIG. The electrical channels between the circuits 103 are conducted.

Finally, please refer to FIG. 4A and FIG. 4B , which show a schematic circuit diagram of a gate driving circuit according to a third preferred embodiment of the present invention at the original resolution and the target resolution. The driving circuit of this embodiment includes a plurality of shift registers 406 - 421 , a plurality of gate lines 424 - 436 , a plurality of register switches 439 - 448 and a plurality of gate line switches 451 - 463 . The biggest difference between this embodiment and the second preferred embodiment lies in the operation mode of the gate line switch. When the register switch is switched to the position shown in FIG. 4B , its operation mode is the same as that of the second preferred embodiment, and the circuits between the shift registers 406 - 421 , the subsequent shift registers and the pixel circuit 103 are turned on. For example, when the electrical channel between the shift register 415 and the shift register 418 is turned on, the gate line switch 460 will turn on the electrical channel between the shift register 415 , the shift register 418 and the pixel circuit 103 . However, when the register switch is switched to the position shown in FIG. 4A , in this embodiment, the gate line switch 451 needs to turn on the first and second shift registers 406, 409 and the pixel circuit 103 in the shift registers 406-421. The channel between them, and the electrical channel between the shift register after the second shift register 409 , the second-stage shift register and the pixel circuit 103 needs to be turned on.

For example, when the electrical channel between the shift register 415 and the shift register 421 is turned on, the gate line switch 463 will switch the electrical channel between the shift register 415, the shift register 421 and the pixel circuit 103 conduction. It should be noted here that when the register switch is switched to the state shown in FIG. 4A , the gate line switch needs to connect the gate lines two by two in sequence. Those skilled in the art will understand that the device of this embodiment does not need to operate except the first shift register 406 when the device of this embodiment has an odd number of shift registers at the target resolution, and thus has the advantage of reducing power consumption.

Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore The protection scope of the present invention depends on the appended claims.

Claims (3)

1. A circuit device for changing resolution of a liquid crystal display panel, adapted to change an original resolution to a target resolution according to a gate control signal, the device comprising: A pixel circuit for generating an image according to a gate driving signal and a source driving signal; A gate driving circuit, coupled to the pixel circuit with a plurality of gate lines, for determining one of an original gate driving signal and a target gate driving signal as the gate according to the gate control signal drive signal, the gate drive circuit includes: a plurality of shift registers for outputting the gate driving signal; and A plurality of register switches are used to switch between the following two states according to the gate control signal, and select to output the original gate drive signal or the target gate drive signal: A. Turning on the electrical channels between the plurality of shift registers and the subsequent shift register; B. Turning on the electrical channels between the plurality of shift registers and the second-stage shift register; Wherein, when the register switch is switched to B, the gate control signal needs to be input to the input terminals of the first shift register and the second shift register at the same time, and A source driving circuit is coupled to the pixel circuit with a plurality of source lines to output the source driving signal according to a source control signal. 2. The circuit device for changing the resolution of a liquid crystal display panel as claimed in claim 1, wherein the gate drive circuit further comprises: A plurality of gate line switches are used to turn on the plurality of shift registers, the subsequent shift register and the electrical channel of the pixel circuit when the register switch is switched to A, and when the register switch When switching to B, the electrical channel between the plurality of shift registers, the second-stage shift register and the pixel circuit is turned on. 3. A circuit device for changing the resolution of a liquid crystal display panel, which is suitable for changing an original resolution to a target resolution according to a gate control signal, the device comprising: A pixel circuit for generating an image according to a gate driving signal and a source driving signal; A gate driving circuit, coupled to the pixel circuit with a plurality of gate lines, for determining one of an original gate driving signal and a target gate driving signal as the gate according to the gate control signal drive signal, the gate drive circuit includes: a plurality of shift registers for outputting the gate driving signal; A plurality of register switches are used to switch between the following two states according to the gate control signal, and select to output the original gate drive signal or the target gate drive signal: A. Turning on the electrical channels between the plurality of shift registers and the subsequent shift register; B. Turn on the electrical channel between the first shift register and the second shift register and the electrical properties between the second shift register and the rear secondary shift register among the plurality of shift registers described later channel; and A plurality of gate line switches are used to turn on the plurality of shift registers, the subsequent shift register and the electrical channel of the pixel circuit when the register switch is switched to A, and when the register switch When switching to B, turn on the first shift register, the electrical channel between the second shift register and the pixel circuit, and the second shift register and the last two shift registers in the subsequent shift registers. stage shift registers and electrical channels between the pixel circuits; Wherein, when the register switch is switched to B, the gate lines need to be sequentially connected in pairs, and A source driving circuit is coupled to the pixel circuit with a plurality of source lines to output the source driving signal according to a source control signal.

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