Patent Application
20100039362
1. Field of Invention
The present invention relates to a control integrated circuit (IC), especially to a control IC for color sequential liquid crystal displays.
2. Description of Related Art
Nowadays due to advanced technology, various new information products are developed and promoted to meet people's requirements. The conventional display device has shortages of large volume, high power consumption and high radiation dose while the liquid crystal display (LCD) features on compact volume, light weight, low radiation dose and low power consumption. Thus the conventional display device is replaced with the LCD which has become a main stream of a current display market. However, the conventional LCD uses color filters for converting light beams into three color light beams-red, green and blue since there are three primary colors required for each pixel. To create a color image, there are three subpixels in each pixel-red, green and blue, respectively corresponding to red, green and blue color filters. Due to persistence of vision, the human eye receives red, green and blue light through the color filters and perceives pixel color. The light transmission of the LCD and single pixel (dot) size are limited by the color filter. Thus display quality of the LCD is affected by the color filter.
In order to solve the above mentioned problem, a color sequential LCD has been developed. In the color sequential display, three primary colors of each pixel are displayed sequentially. A frame is decomposed into red, green, and blue fields displayed in successively. The three fields are illuminated by the red, green, and blue backlight accordingly. Relying on the human vision system, the successive images are fused into a color image. Thus the sequential display includes no color filter. Moreover, in contrast to pixel size of the LCD with color filter, the pixel size of the sequential display is smaller. Therefore, the color sequential display has higher resolution with lower cost.
Refer to
The microprocessor 16 generates corresponding time signals according to the frames intended to be displayed and the time signals are sent to the light-source driving circuit 10 and the scan driving circuit 14 for timing control of the generated scan signals and driving signals. And the display data is sent to the data driving circuit 12. Generally, the microprocessor 16 needs to control timing of the scan data from the scan driving circuit 14 matching timing of the drive signal from the light-source driving circuit 10 so as to make timing of the scan signal matches timing of the backlight module generating the color backlights. Yet the microprocessor 16 is not only for control of the color sequential display, it also used for control of electronics disposed with itself such as handhold game consoles, and digital photo frames. This means the microprocessor 16 needs to execute commands and launch applications of the electronics. Due to heavy of the microprocessor 16, the electronics are unable to run smoothly. Moreover, the microprocessor 16 generates clock signals through program operation or calculation of an internal counter so that timing of the light-source driving circuit 10 and timing of the scan driving circuit 14 are unable to be precisely controlled and matched with each other. Thus the scan signals generated by the scan driving circuit 14 are also unable to match the color backlights generated by the backlight module 22 precisely. Therefore, quality of the frame displayed on the display panel 20 is under the influence.
Furthermore, the microprocessor 16 requires additional several pins such as GPIO pins for timing control of the light-source driving circuit 10 and the scan driving circuit 14 so as to make them match each other. Thus the number of pins of the microprocessor 16 is increased and the occupied are also increased so that the cost is raised. The volume of the electronic is highly related to the area of the whole control circuit occupied. Thus the compact volume and light weighted requirements of the device are unable to be achieved. In addition, an external Power IC 18 is used as a high-voltage power supply to provide power to the light-source driving circuit 10, the data driving circuit 12, and the scan driving circuit 14. This also leads to increasing of the cost.
Thus there is a need to provide a control IC for the color sequential LCD that overcomes shortcomings of conventional color sequential LCD such as overloading of the microprocessor and large occupied area and enables the scan driving circuit to match the light-source driving circuit precisely for solving the problems mentioned above.
Therefore it is a primary object of the present invention to provide a control IC for color sequential liquid crystal displays that includes a timing generator for precise control of timing of the scan driver circuit, timing of the data driving circuit and timing of the light-source driving circuit and matching with one another so as to improve display quality of the color sequential LCD.
It is another object of the present invention to provide a control IC for color sequential liquid crystal displays that reduces loading on the microprocessor so as to make the microprocessor run and launch applications of the electronics with the color sequential LCD smoothly.
It is a further object of the present invention to provide a control IC for color sequential liquid crystal displays that reduces number of pins of the microprocessor for reducing cost and occupied area.
It is a further object of the present invention to provide a control IC for color sequential liquid crystal displays that integrates a power supply circuit for reducing cost.
In order to achieve above objects, a control IC for color sequential liquid crystal displays of the present invention includes an interface, a timing generator, a data driving circuit and a scan driver circuit. The interface is coupled to a microprocessor, and the interface receives a command and at least one display data of the microprocessor therefore. The timing generator generates a driving timing signal, a data timing signal and a scan timing signal, respectively corresponding to the light-source driver circuit, the data driving circuit and the scan driving circuit according to the received command. Then the light-source driving circuit generates a plurality of driving signals according to the driving timing signal, the data driving circuit receives the display data for generating a data signal according to the data timing signal, and the scan driving circuit generates a scan signal according to the scan timing signal. Those driving signals are used to control the color sequential LCD for generating a plurality of color backlights. In accordance with the data signal, the scan signal, and the color backlights, the color sequential LCD shows a frame. Moreover, besides the light-source driver circuit, a power supply circuit is further integrated into the control IC so that there is no need to use an external IC for reducing cost.
The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed descriptions of the preferred embodiments and the accompanying drawings, wherein
Refer to
The interface 32 is coupled to a microprocessor 60 for receiving a command and at least one display data. According to frames intended to be displayed on the color sequential LCD, the microprocessor 60 sends corresponding commands and display data. The interface 32 is further coupled to a data storage unit 322 as well as a command register 324. The data storage unit 322 is for storing displayed data received by the interface 32 and the command register 324 is to temporarily store the command received by the interface 32 and send the command to the timing generator 34. The data storage unit 322 can be a memory, a random access memory such as static random access memory or dynamic random access memory. In accordance with the command from the command register 324, the timing generator 34 generates a driving timing signal, a data timing signal and a scan timing signal, respectively sent to the light-source driving circuit 41, the data storage unit 322 and the scan driving circuit 40. The light-source driving circuit 41 generates a plurality of driving signals according to the driving timing signal and sends these driving signals to the backlight module 52 of the display panel 50 so as to make the backlight module 52 generates a plurality of color backlights sequentially. The color backlights includes a red backlight, a green backlight, and a blue backlight or some other backlight of other colors.
According to the data timing signal, data storage unit 322 sends the stored display data to the data driving circuit 38 for generating a data signal. That means the data driving circuit 38 generates a data signal according to the received display data. The data driving circuit 38 also sends the data signal to the display module 54 of the display panel 50. As to the scan driving circuit 40, it generates a scan signal according to the scan timing signal and sends the scan signal to the display module 54 of the display panel 50. Thus the display module 54 displays a frame according to the scan signal, the data signal and these color backlights. The display panel 50 of the color sequential LCD displays frames according to the scan signal, the data signal and the color backlights sequentially generated by the backlight module 52. As to the display module 54, it controls rotation angle of liquid crystal therein according to scan signal level and data signal level so as to determine light transmittance of the color backlights and further display the frames. Furthermore, the timing generator 34 adjusts pulse width of the driving timing signal and the scan timing signal in accordance with colors of different frames so as to adjust time of the scan driving circuit 40 to generate scan signals. The timing generator 34 also controls the light-source driving circuit 41 to adjust pulse width of driving signals for further adjustment of time of the backlight module 52 to generate color backlights.
Refer back to
As to the power supply circuit 46, it includes a charge pump 462 and a follower circuit 464. According to the oscillation signal, the charge pump 462 generates a first high-voltage power supply for providing the follower circuit 464 and the light-source driving circuit 41 electrical power. According to the first power supply from the charge pump 462, the follower circuit 464 generates a second high-current power supply for providing electrical power to the data driving circuit 38 and the scan driving circuit 40. In this embodiment, the light-source driving circuit 41 is disposed outside the control IC 30 so that the light-source driving circuit 41 can also be powered by an external power supply. Due to integration of the interface 32, the timing generator 34, the data driving circuit 38, the scan driving circuit 40, the oscillator 42, the clock generator 44 and the power supply circuit 46 into the control IC 30, the occupied area is decreased so that the cost is also reduced.
The microprocessor 60 only needs to send commands to the control IC 30. The matching of timing of the scan driving circuit 40 with timing of the light-source driving circuit 41 is controlled by the scan timing signal and the driving timing signal generated by the timing generator 34. Thus the microprocessor 60 will not calculate to generate timing signals for control of the scan driving circuit 40 and the light-source driving circuit 41. Therefore, the load of the microprocessor 60 is reduced and it can control the electronic device with the color sequential LCD precisely and the electronic device can run smoothly. Moreover, there is no need to add control pins on the microprocessor 60 so that the cost will not be raised. Furthermore, by the timing generator 34 that controls the light-source driving circuit 41 to generate timing of the driving signals and controls the scan driving circuit 40 to generate timing of the scan signals, the scan signals can precisely match color backlights generated from the backlight module 52 so that quality of frames displayed on the display panel 50 is further improved. In addition, due to the simple power supply circuit 46 integrated in the control IC 30, it can provide electrical power to the data driving circuit 38, the scan driving circuit 40 and the light-source driving circuit 41. There is no need to dispose an external power IC that costs much higher. Thus the cost is reduced.
Refer to
In summary, a control IC for color sequential LCD according to the present invention integrates a timing generator therein for precise timing control of the scan driver circuit, the data driving circuit and the light-source driving circuit and reduction of loading of the microprocessor. Moreover, the light-source driver circuit, the scan driver circuit, and the data driving circuit of the control IC is powered by the power supply circuit so that the total cost of the whole circuit is reduced.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 097130867 | Aug 2008 | TW | national |
