Color liquid crystal display apparatus with improved display color mixing

• US 4,642,628 A
• Filed: 06/17/1985
• Issued: 02/10/1987
• Est. Priority Date: 06/22/1984
• Status: Expired due to Term

• Current Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Original Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Inventors: Murata, Mitsuhiro
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Kovalick, Vincent P.
• Application Number:
  US06/745,774
• Time in Patent Office: 603 Days
• Field of Search: 340/784, 340/703, 340/805, 340/800, 340/799, 340/802, 358/17, 358/88, 358/3, 358/152, 350/332
• US Class Current: 345/88
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: H04N 3/127 using liquid crystals

Abstract

A color liquid crystal display device such as a television receiver employing an array of R, G and B color filters and corresponding liquid crystal display elements, having the color filters arranged in different sequences in mutually adjacent scanning lines, and having a line memory in which display data for the R, G and B display elements of each display line are successively stored and applied to a drive circuit, is provided with color signal processing circuits for controlling R, G and B digital color signals which act to set these color signals into the line memory at the start of each horizontal scanning interval in a correct array sequence for the line of display elements which will be driven during that horizontal scanning interval.

Claims

1. A color liquid crystal display apparatus, comprising :

a color liquid crystal display unit having a matrix array of liquid crystal display elements with scanning electrodes and data electrodes, and a matrix array of red, green and blue color filters positioned in correspondence with said liquid crystal display elements, said red, green and blue color filters being arrayed along each row of said matrix such as to be arranged in respectively different sequences in mutually adjacent rows;

a data electrode drive circuit for applying drive signals to said data electrodes and a scanning electrode drive circuit for sequentially selecting rows of said display element matrix by applying drive signals to said scanning electrodes;

a line memory for storing display data for successive ones of said rows of display elements and for applying said data to said data electrode drive circuit;

a control section for producing a plurality of control and timing signals including signals for controlling sequential driving of said scanning electrodes whereby each of said liquid crystal display element rows is driven in accordance with said display data during a corresponding horizontal scanning interval of fixed duration during each of successive frame intervals;

a source of successively produced sets of parallel R (red), G (green) and B (blue) digital color signals each comprising at least one bit and constituting said display data for a mutually adjacent set of liquid crystal display elements in a row of said matrix;

selection switch control means having a plurality of output terminals and having a plurality of input terminals coupled to receive said R, G and B digital color signals from said source thereof, and responsive to control signals produced by said control section for transferring respective ones of said R, G and B digital color signals from said input terminals to specific ones of said output terminals in accordance with the status of display matrix row selection, and;

signal shifting circuit means coupled to receive said R, G and B digital color signals from said output terminals of said selection switch control means, and acting to arrange said R, G and B digital color signals, successively output in parallel from said output terminals during each of said horizontal scanning intervals, in a fixed array sequence during said each horizontal scanning interval;

said line memory being responsive to one of said timing signals from said control section for storing said sequentially arrayed contents of said signal shifting circuit means therein at the termination of said each horizontal scanning interval.

2. A color liquid crystal display apparatus according to claim 1, in which said selection switch control means comprise a parallel/parallel converter circuit including logic gate circuits controlled by said control signals from said control section for selectively transferring said R, G and B digital color signals to said output terminals of said parallel/parallel converter circuit.

3. A color liquid crystal display apparatus according to claim 2, in which said control section comprises circuit means for generating a horizontal sync pulse in synchronism with each of said horizontal scanning intervals and a vertical sync pulse in synchronism with each of said frame intervals, line counter circuit means for counting said horizontal sync pulses under the control of said vertical sync pulses, and decoder circuit means for decoding the count contents of said line counter circuit means to produce said control signals varying in accordance with said matrix row selection status.

4. A color liquid crystal display apparatus according to claim 2, in which said color liquid crystal display apparatus comprises a television receiver including a television signal receiving section for receiving a television signal and circuit means for deriving R, G and B analog color signals from said television signal, and further comprising first, second and third analog/digital converter circuits for converting said R, G and B analog color signals respectively into said R, G and B digital color signals in response to said timing signals from said control section, and moreover comprising sync separator circuit means for deriving said horizontal and vertical sync pulses from said television signal.

5. A color liquid crystal display apparatus according to claim 1, in which said signal shifting circuit means comprise first, second and third serial/parallel converter circuits controlled by said timing signals from said control section, each having a serial data input terminal coupled to a corresponding one of said output terminals of said selection switch control means and having a plurality of parallel data output terminals coupled to corresponding input terminals of said line memory.

6. A color liquid crystal display apparatus according to claim 1, in which said signal shifting circuit means comprise:

a parallel/serial converter circuit controlled by said timing signals from said control section, having a set of parallel data input terminals respectively coupled to said output terminals of said selection switch control means, and having a serial data output terminal, and;

a serial/parallel converter circuit having a serial data input terminal coupled to said serial data output terminal of said parallel/serial converter circuit and a plurality of parallel data output terminals coupled respectively to corresponding input terminals of said line memory;

with said timing signals applied from said control section to said parallel/serial converter circuit acting to shift said successive sets of R, G and B color signal data output from said selection switch control means into said parallel/serial converter circuit in parallel form and to thereupon shift said data in serial form from said parallel/serial converter circuit into said serial/parallel converter circuit.