APPARATUS AND METHOD FOR COLOR SHIFT COMPENSATION IN DISPLAYS

• US 20100013864A1
• Filed: 12/08/2006
• Published: 01/21/2010
• Est. Priority Date: 12/16/2005
• Status: Active Grant

• Current Assignee: Dynamic Data Technologies LLC
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Brunner, Patrick, Oelhafen, Patrick
• Granted Patent: US 8,619,016 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

Active matrix display module (10) comprising a driving circuit with a source driver (20) and a gate driver (12). Furthermore, a display panel (11) with pixels consisting of three sub-pixels is provided. The sub-pixels are arranged in rows and columns and each sub-pixel comprises a sub-pixel selection transistor arranged at an intersection of a row and a column. The gate driver (12) is employed to select and deselect all pixels of a row of the display panel (11) and the source driver (20) is employed for providing the required voltage levels to all sub-pixels of a currently selected row, said voltage levels corresponding to the desired intensity for each color. Demultiplexer switches (21) are integrated onto the display panel (11) for demultiplexing columns of the display panel (11). The active matrix display module (10) further comprises means (18) for color shift compensation. These means (18) implement a selection order for the selection of the sub-pixels to compensate unintentional color shifts. The compensation takes place

Claims

1. Active matrix display module comprising:

a driving circuit with a source driver and a gate driver,

a display panel with pixels consisting of three sub-pixels being arranged in rows and columns, each sub-pixel comprising a sub-pixel selection transistor arranged at an intersection of a row and a column,

said gate driver being employed to select and deselect all pixels of a row of said display panel,

said source driver being employed for providing required voltage levels to all sub-pixels of a currently selected row of said display panel, said voltage levels corresponding to the desired intensity for each color,

demultiplexer switches being integrated onto the display panel for demultiplexing columns of said display panel, and

means for color shift compensation implementing a selection order for the selection of the sub-pixels in order to compensate unintentional color shifts, said compensation taking place within two frames.

2. The display module of claim 1, wherein the during the color shift compensation in a first frame the color shift is partially compensated and in a second frame the color shift is completely compensated.

3. The display module of claim 2, wherein during a third frame the DC value of the first frame is averaged to 0V on each sub-pixel and during a fourth frame the DC value of the second frame is averaged to 0V on each sub-pixel in order to avoid the deterioration of the display panel.

4. The display module of claim 1, wherein said source driver and/or said gate driver is integrated into a display glass forming the display panel.

5. The display module of claim 1, wherein each pixel has a storage capacitor and a pixel capacitance.

6. The display module of claim 4, wherein all sub-pixels of a row become isolated if this row is deselected by said gate driver and wherein the voltage level for each sub-pixel is maintained by the storage capacitor and the pixel capacitance.

7. The display module of claim 1, wherein said display module is a low temperature polysilicon display module or a high temperature polysilicon display module.

8. Method for the color shift compensation implemented in an active matrix display module comprising a driving circuit with a source driver and a gate driver, and a display panel with pixels consisting of three sub-pixels being arranged in demultiplexing columns, each sub-pixel comprising a sub-pixel selection transistor arranged at an intersection of a row and a column and corresponding demultiplexer selection lines implementing a 1:

3 multiplexing scheme where each pixel belongs to a different multiplexing group, the method comprising the following steps;

during a first frame;

(1) selecting a row by the gate driver,

(2) charging all sub-pixels in the middle of a multiplexing group of said row by applying a respective signal pulse on a corresponding demultiplexer selection line,

(3) charging one of the two neighboring sub-pixels of each multiplexing group of said row with a first voltage polarity, and selecting an adjacent sub-pixel of an adjacent multiplexing group at the same time,

(4) charging the other neighbor sub-pixel of the middle sub-pixel of each multiplexing group of said row with a voltage polarity opposite to the first voltage polarity, whereby two sub-pixels of the two adjacent multiplexing groups are selected simultaneously,

(5) repeating the steps (1)-(4) for every row until the whole display panel is addressed,

during a second, subsequent frame;

(6) inverting the polarity of the two adjacent sub-pixels of the middle sub-pixel of each multiplexing group of a row and charging the respective middle sub-pixels with the same polarity as in step (2),

(7) repeating the step (6) for every row until the whole display has been addressed.

9. The method of claim 8 whereby said first and second frames are repeated with inverted polarity in order to average out the DC value on each sub-pixel to 0V.

10. Method for the color shift compensation implemented in an active matrix display module comprising a driving circuit with a source driver and a gate driver, and a display panel with pixels consisting of three sub-pixels being arranged in rows and columns, each sub-pixel comprising a sub-pixel selection transistor arranged at an intersection of a row and a column and corresponding demultiplexer selection lines implementing a 1:

6 multiplexing scheme subdividing said display panel into different multiplexing group where each multiplexing group comprises two adjacent pixels, the method comprising the following steps;

during a first frame;

(1) selecting a row by the gate driver,

(2) sequentially charging three sub-pixels of every multiplexing group such that every second sub-pixel gets selected,

(3) sequentially charging three so far un-selected sub-pixels such that each sub-pixel that was charged during the step (2) now has on the left and right hand side sub-pixels with inverse polarity,

(4) repeating the previous steps (1)-(3) for every row until the whole display panel is addressed,

during a second, subsequent frame;

(5) identically charging in said second frame the same three sub-pixels of every multiplexing group as in step (2),

(6) charging the remaining sub-pixels with the inverse polarity with respect to the steps (1)-(3),

(7) repeating the previous steps (5) and (6) for every row until the whole display panel is addressed.

11. The method of claim 10 whereby in a third frame the DC value of the first frame is averaged out to 0V on each sub-pixel.

12. The method of claim 11 whereby in a fourth frame the DC value of the second frame is averaged out to 0V on each sub-pixel.