News Column

Patent Issued for Scan-Type Display Device Control Circuit

July 8, 2014



By a News Reporter-Staff News Editor at Information Technology Newsweekly -- A patent by the inventors Wu, Ken-Tang (Hsinchu, TW); Shih, Fu-Yang (Hsinchu, TW), filed on February 17, 2010, was published online on June 24, 2014, according to news reporting originating from Alexandria, Virginia, by VerticalNews correspondents.

Patent number 8760458 is assigned to Macroblock, Inc. (Hsinchu, TW).

The following quote was obtained by the news editors from the background information supplied by the inventors: "The present invention relates to a circuit, and more particularly to a scan-type display device control circuit.

"In recent years, the cost of manufacturing light-emitting diodes (LEDs) is greatly reduced. Therefore, LED displays have been widely applied in various occasions, such as gymnasiums and billboards.

"Usually, an LED display device uses thousands of LEDs as displaying pixels. A frame may be constituted by pixels having different brightness, and multiple frames may be displayed in sequence to constitute a dynamic image.

"The pixels are controlled by a controller respectively. According to input data, the controller transmits an ON signal or an OFF signal to an LED driver, thereby controlling the brightness of the pixels.

"Generally speaking, the dynamic image will switch about 60 frames every second. That is to say, a frame rate of the input frames is 60 Hz. Since the period of switching the frames is very short, when watching the progressive image, people will feel that the progressive image is continuous due to the visual staying phenomenon.

"Furthermore, the time for displaying a whole frame is referred to as a refresh time. The inverse number of the refresh time is a refresh rate. The higher the refresh rate is, the more difficulty the LED display device flickers (for example, when taking a photo by using a high-speed shutter of a photography appliance).

"In another aspect, quite a number of LED drivers are required in a common LED display device. In order to reduce the number of the LED drivers, the LED display device can adopt a scan-type controller. In the scan-type controller, multiple LEDs may be driven in different time by a switching device. Therefore, the same one LED driver may drive multiple LEDs.

"Although the scan-type controller can save the number of LED drivers, for the same LED driver, the data quantity to be processed is multiplicative. That is to say, the LED driver needs a larger transmission band width. Furthermore, since more time will be spent for displaying a whole frame, the refresh rate will descend accordingly."

In addition to the background information obtained for this patent, VerticalNews journalists also obtained the inventors' summary information for this patent: "Accordingly, the present invention is a scan-type display device control circuit, which is capable of enhancing a refresh rate of a scan-type display device and reducing a transmission band width of an LED driver.

"The present invention provides a scan-type display device control circuit, which is suitable for receiving a plurality of successive frame data and driving a light-emitting diode (LED) display device accordingly. The scan-type display device control circuit comprises a ping-pong buffer, a data storage controller, a line scan controller, a display buffer, and a scrambled pulse width modulation (PWM) signal generating device.

"The ping-pong buffer comprises a first storage area and a second storage area. The data storage controller receives the frame data in sequence and stores the frame data in the first storage area or the second storage area alternately. The line scan controller, logically connected to the ping-pong buffer, is used to capture line data in the frame data from the first storage area or the second storage area alternately. The display buffer, logically connected to the line scan controller, is used to temporarily store the line data.

"The scrambled PWM signal generating device is logically connected to the display buffer and the line scan controller. The scrambled PWM signal generating device captures the line data and generates a scrambled PWM signal according to the line data, so as to drive the LED display device.

"In an embodiment of the present invention, the line data is M bits. After elapsing of a scan line changing period, the scrambled PWM signal generating device captures another line data and generates another scrambled PWM signal according to the other line data. The scan line changing period is 2.sup.N operation periods, and N is smaller than M.

"In another embodiment of the present invention, the line data is M bits. After elapsing of a scan line changing period, the scrambled PWM signal generating device captures another line data and generates another scrambled PWM signal according to the other line data. The scan line changing period is 2.sup.N operation periods plus a deadtime period, and N is smaller than M.

"The present invention provides another scan-type display device control circuit, which is suitable for receiving a plurality of successive frame data and driving an LED display device accordingly. The scan-type display device control circuit comprises a ping-pong buffer, a data storage controller, a line scan controller, and a pulse width modulation (PWM) signal generating device. The line scan controller, after elapsing of a scan line changing period, captures another line data of the frame data, and transmits the other line data to the PWM signal generating device. The scan line changing period is 2.sup.N operation periods plus a deadtime period.

"The scan-type display device control circuit can utilize frame data circularly and repeatedly, so as to prevent a great mass of data from being transmitted repeatedly. Therefore, a band width for inputting data can be reduced significantly. Furthermore, the scrambled PWM signal generating device can scramble a PWM signal with a long period into a plurality of scrambled PWM signals with a short period. Therefore, the refresh rate can be efficiently enhanced without changing the band width for inputting data."

URL and more information on this patent, see: Wu, Ken-Tang; Shih, Fu-Yang. Scan-Type Display Device Control Circuit. U.S. Patent Number 8760458, filed February 17, 2010, and published online on June 24, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8760458.PN.&OS=PN/8760458RS=PN/8760458

Keywords for this news article include: Macroblock Inc, Information Technology, Information and Data Storage.

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Source: Information Technology Newsweekly


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