Video signal converting apparatus with display mode conversion and a display device having the same

• US 6,219,023 B1
• Filed: 07/07/1997
• Issued: 04/17/2001
• Est. Priority Date: 07/05/1996
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Byoung-Han
• Primary Examiner(s): Hjerpe, Richard A.
• Assistant Examiner(s): Blackman, Anthony J.
• Application Number:
  US08/889,131
• Time in Patent Office: 1,380 Days
• Field of Search: 345/127, 345/130, 345/132, 345/150, 345/302
• US Class Current: 345/698
• CPC Class Codes: G06T 3/40 Scaling of whole images or parts thereof, e.g. expanding or contracting
• CPC Class Codes: G09G 2340/0414 Vertical resolution change
• CPC Class Codes: G09G 2340/0421 Horizontal resolution change
• CPC Class Codes: G09G 2360/02 Graphics controller able to handle multiple formats, e.g. input or output formats
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 5/18 Timing circuits for raster scan displays specially adapted for television H04N ; synchronisation between the display unit and other display units, videodisc player G09G5/12
• CPC Class Codes: H04N 7/0105 using a storage device with different write and read speed

Abstract

A video signal converting apparatus converts a low-resolution video signal from a host into a different-resolution video signal capable of being displayed on the entire screen of a high-resolution supporting display device. The apparatus has a memory for storing the digital video signals and a horizontal output generator. The horizontal output generator receives first and second data signals and a horizontal synchronization signal and generates a horizontal output signal for enabling the digital video signals corresponding to each horizontal line of the second display to be stored or read from the memory. A number of pixels per cycle of the horizontal output signal is equal to a value of the first data signal, and a number of pixels per pulse width of the horizontal output signal is equal to a value of the second data signal. The apparatus has a memory controller for controlling reading and storing operations of the memory in accordance with the horizontal and vertical synchronization signals, the horizontal output signal, the first data signal, a third data signal determined according to frequencies of the horizontal and vertical synchronization signals, a first pixel clock signal for a write operation of the memory and a second pixel clock signal for a read operation of the memory.

Claims

1. A liquid crystal display (LCD) device for receiving horizontal and vertical synchronization signals and at least one analog video signal synchronized with said horizontal video signal from a host and displaying an image on a screen thereof, said LCD device comprising:

a display mode discriminating means for discriminating a display mode supported by said host in response to said horizontal and vertical synchronization signals to generate first and second mode signals and first, second, third, fourth and fifth data signals related to said discriminated display mode;

a clock generator for generating first and second pixel clock signals in synchronization with said horizontal synchronization signal, said first and second pixel clock signals respectively having frequencies corresponding to said first and second data signals, a number of pulses of said first pixel clock signal corresponding to one horizontal line being equal to a value of said first data signal, and a number of pulses of said second pixel clock signal corresponding to one horizontal line being equal to a value of said second data signal;

an analog-to-digital converter (ADC) for converting said at least one analog video signal into a digital video signal in synchronism with said first pixel clock signal;

a memory for storing said digital video signal;

a horizontal output generator for receiving said third and fourth data signals in response to said vertical synchronization signal and generating a horizontal output signal, said digital video signal being read from said memory in synchronism with said horizontal output signal, a number of pixels per cycle of said horizontal output signal being equal to a value of said third data signal, and a number of pixels per pulse width of said horizontal output signal being equal to a value of said fourth data signal; and

a memory controller for controlling reading and storing operations of said memory in accordance with said horizontal synchronization signal, said horizontal output signal, said third and fifth data signals, and said first and second pixel clock signals, said reading operation being delayed from a rising edge of said horizontal synchronization signal to a period corresponding to a value of said fifth data signal and then activated, whereby said reading and storing operations are not simultaneously activated.

2. The LCD device of claim 1, said clock generator comprising two PLL (phase locked loop) circuits which are respectively initialized in accordance with said first and second data signals.

3. The LCD device of claim 1, said memory comprising:

at least three line memories for storing said digital video signal from the ADC and corresponding to one horizontal line, and a means for selectively outputting data from said line memories in response to a data selection signal from said memory controller.

4. The LCD device of claim 1, said ADC converting analog R (red), G (green) and B (blue) signals into digital R, G and B signals, respectively, and said memory comprising three memory blocks corresponding to said digital R, G and B signal and three multiplexers;

each of said three memory blocks having at least three line memories, each of which stores said digital video signal from said ADC and corresponding to one horizontal line, and each of said three multiplexers selectively outputting data from said line memories in response to a data selection signal from said memory controller.

5. The LCD device of claim 4, said memory controller comprising:

a memory operation control circuit for receiving said third and fifth data signals and said first and second pixel clock signals, and for providing a first enable signal for said reading operation to one of said line memories and a second enable signal for said storing operation to another of said line memories;

an address generator for generating read and write address signals in response to said first and second pixel clock signals, said horizontal synchronization signal and said horizontal output signal;

an address selection circuit for selecting said read and write address signals by means of said memory operation control circuit to provide a selected address signal to each of said line memories; and

a clock selection circuit for selecting said first and second pixel clock signals by means of said memory operation control circuit to provide said selected pixel clock signal to each of said line memories.

6. The LCD device of claim 5, said memory operation control circuit comprising:

means for generating a write starting control signal in response to said third and fifth data signals, said write starting control signals being indicative of the write operation;

a means for generating write enable signals corresponding to said line memories and first and second memory index signals in response to said first pixel clock signal and said write starting control signal, said first and second index signals being indicative of enabled states of said line memories; and

a means for generating read enable signals corresponding to said line memories in response to said second pixel clock signal and said first and second memory index signals.

7. The LCD device of claim 1, said horizontal output generator comprising:

a counter for loading a value of said third data signal in response to said vertical synchronization signal and down-counting said value every rising edge of said second pixel clock signal;

a first comparator for comparing said third data signal with an output signal of said counter to generate a first comparison signal;

a second comparator for comparing a value of least significant n-bits of said second data signal with said fourth data signal to generate a second comparison signal, n being a positive integer; and

a JK-flip-flop for receiving said first and second comparison signals through J and K input terminals thereof.

8. The LCD device of claim 1, said memory, said horizontal output generator and said memory controller together comprising a single chip.

9. An apparatus for converting analog video signals of a first display into digital video signals of a second display, comprising:

a memory for storing said digital video signals,

a horizontal output generator for receiving first and second data signals and a horizontal synchronization signal and for generating a horizontal output signal for enabling said digital video signals corresponding to each horizontal line of said second display to be stored or read from said memory, a number of pixels per cycle of said horizontal output signal being equal to a value of said first data signal, and a number of pixelse per pulse width of said horizontal output signal being equal to a value of said second data signal; and

a memory controller for controlling reading and storing operations of said memory in accordance with said horizontal synchronization signal and a vertical synchronization signal, said horizontal output signal, said first data signal, a third data signal determined according to frequencies of said horizontal and vertical synchronization signals, a first pixel clock signal for a write operation of said memory and a second pixel clock signal for a read operation of said memory.

10. The apparatus of claim 9, said video signal converting apparatus comprising a single chip.