Display device

• US 20030117422A1
• Filed: 08/21/2002
• Published: 06/26/2003
• Est. Priority Date: 12/20/2001
• Status: Active Grant

• Current Assignee: Hitachi Displays Limited (Japan Display Incorporated), Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Yamamoto, Tsunenori, Konno, Akitoyo, Hiyama, Ikuo, Tsumura, Makoto
• Granted Patent: US 6,909,442 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2340/02 Handling of images in compressed format, e.g. JPEG, MPEG
• 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: G09G 3/3659 the addressing of the pixel involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependant on signal of two data electrodes

Abstract

A display device including a plurality of blocks of pixels each of which includes a red subpixel, a green subpixel, and a blue subpixel, each of the blocks including pixels in a form of a matrix having N rows and M columns includes a first active element shared among three subpixels of each pixel and a second active element connected to a second active element formed in each subpixel connected to the first active element. Ma gradation voltage lines (Ma is an integer; M≧Ma≧2) respectively of red, green, and blue subpixels in a direction of the column are commonly connected. The display device directly displays a compressed image signal without developing the image signal into a bit map in which each subpixel has gradation information.

Claims

1. A display device, comprising a plurality of blocks of pixels each of which includes subpixels respectively of three colors, each of said blocks including pixels in a form of a matrix having N rows and M columns, wherein

said device directly displays a compressed image signal without developing the signal into a bit map in which each subpixel has gradation information.

2. A display device according to claim 1, wherein said image signal is compressed in a spatial axis and in a gradation axis.

4. A display device according to claim 1, further comprising:

a first active element shared among three subpixels constituting each said pixel; and

a second active element constructed for each said subpixel connected to said first active element.

5. A display device according to claim 1, further comprising:

Ma gradation voltage lines of said gradation voltage lines commonly connected (Ma is an integer;

M≧

Ma≧

2) for said subpixels respectively of three colors in a direction of the column.

6. A display device according to claim 1, wherein:

said device operates in an image compression and transfer method in which a lookup table of n gradation levels (n is less than N×

M) is defined for said pixel block before said pixel block is transferred and a discriminating signal having gradation thereof is transferred for each pixel in said block, and

said device displays an image signal of the image compression and transfer method without developing the image signal.

7. A display device according to claim 1, wherein:

said device operates in an image compression and transfer method in which a lookup table of n gradation levels (n is less than N×

M) is defined for each pixel block of which gradation frequently changes between a plurality of frames, before said pixel block is transferred, and a discriminating signal having gradation thereof is transferred for each pixel in said block, and

said device displays an image signal of the image compression and transfer method without developing the image signal.

8. A display device according to claim 1, wherein:

said device operates in an image compression and transfer method in which a lookup table of m gradation levels (m is less than N×

M) for a plurality of frames is defined for each pixel block of which gradation changes less frequently between a plurality of frames, before said pixel block is transferred, and a discriminating signal having gradation thereof for a plurality of frames is transferred for each pixel in said block, and in which a lookup table of n gradation levels (n is less than N×

M;

m>

n) in a single frame is defined for each pixel block of which gradation changes frequently between a plurality of frames, before said pixel block is transferred, and a discriminating signal having gradation thereof in the single frame is transferred for each pixel in said block, and

said device displays an image signal of the image compression and transfer method without developing the image signal.

19. A display device according to claim 1, wherein said three colors are red, green, and blue.

3. A display device, comprising a plurality of blocks of pixels each of which includes subpixels respectively of three colors, each of said blocks including pixels in a form of a matrix having N rows and M columns, wherein

each said pixel includes a function of developing a compressed image signal into gradation information of each said subpixel.

9. A display device, comprising:

a plurality of blocks of pixels each of which includes subpixels respectively of three colors, each of said blocks including pixels in a form of a matrix having N rows and M columns;

a subpixel electrode disposed in each said pixel;

a display element disposed in said each subpixel, said element operating according to a voltage on said subpixel electrode;

a scanning line driving circuit for supplying a scanning signal to scanning lines arranged substantially parallel to each other;

a discriminating signal line driving circuit for supplying a discriminating signal to discriminating signal lines arranged substantially vertical to said scanning lines;

holding means for holding in said pixel a discriminating signal from said discriminating line;

a gradation voltage line driving circuit for supplying a gradation voltage to Ma gradation voltage lines of said gradation voltage lines for supplying a gradation voltage to each said subpixel, said Ma gradation voltage lines being commonly connected (Ma is an integer;

M≧

Ma≧

2) for said subpixels respectively of three colors of red, green, and blue in a direction of the column;

a circuit for selecting a gradation voltage according to said discriminating signal; and

a switch for applying the gradation voltage selected by said selecting circuit to said subpixel electrode.

10. A display device according to claim 9, wherein:

said display element is a light modulating element using liquid crystal;

said holding circuit includes a first active element which includes said scanning line as a gate terminal thereof and which is respectively shared among subpixels respectively of the three colors connected to said discriminating line and intra-pixel memory capacity, and two gradation voltage lines are arranged for one subpixel;

said gradation voltage selecting circuit includes an n-type active element and a p-type active element of which respective gate terminals are connected to said intra-pixel memory capacity and which are respectively connected to two gradation voltage lines; and

said switch includes a fourth active element connected to an (n,p)-type active element and said subpixel electrode, said fourth active element including a gradation write line as a gate terminal thereof.

11. A display device according to claim 9, wherein:

said display element is a light modulating element;

said holding circuit includes a first active element which includes said scanning line as a gate terminal thereof and which is respectively shared among subpixels respectively of the three colors connected to said discriminating line and intra-pixel memory capacity, and two gradation voltage lines are arranged for one subpixel;

said gradation voltage selecting circuit includes an n-type active element and a p-type active element of which respective gate terminals are connected to said intra-pixel memory capacity and which are respectively connected to two gradation voltage lines;

said switch includes a fourth active element connected to an (n,p)-type active element and said subpixel electrode, said fourth active element including a gradation write line as a gate terminal thereof; and

said display element is a light emitting diode (LED) element which includes said subpixel electrode as a gate terminal thereof and which is driven by a fifth active element.

12. A display device according to claim 9, wherein:

said display element is a light modulating element using liquid crystal;

said holding circuit includes a first active element which includes said scanning line as a gate terminal thereof and which is shared among subpixels respectively of the three colors connected to said discriminating line and intra-pixel memory capacity, and one said gradation voltage line is arranged for one said subpixel;

said gradation voltage selecting circuit includes an n-type active element and a p-type active element of which respective gate terminals are connected to said intra-pixel memory capacity and which are respectively connected to two gradation voltage lines of an adjacent subpixel and own pixel, respectively; and

said switch includes a fourth active element connected to an (n,p)-type active element and said subpixel electrode, said fourth active element including a gradation write line as a gate terminal thereof.

13. A display device according to claim 9, wherein:

said display element is a light modulating element using liquid crystal;

said holding circuit includes a first active element which includes said scanning line as a gate terminal thereof and which is shared among subpixels respectively of the three colors connected to said discriminating line and intra-pixel memory capacity, and one said gradation voltage line is arranged for one said subpixel;

said circuit to select an output of the gradation voltage includes a second active element of which a gate terminal is connected to said intra-pixel memory capacity and which and which is connected to said gradation voltage line; and

said switch includes a third active element connected to said second active element and said subpixel electrode, said third active element including a gradation write line as a gate terminal thereof.

14. A display device according to claim 9, wherein:

said display element is a light modulating element using liquid crystal;

said holding circuit includes a first active element which includes said scanning line as a gate terminal thereof and which is shared respectively among subpixels respectively of the three colors connected to said discriminating line and intra-pixel memory capacity, and one said gradation voltage line is arranged for one said subpixel;

said circuit to output the gradation voltage to said subpixel electrode includes a second active element of which a gate terminal is connected to said intra-pixel memory capacity and which is connected to said gradation voltage line.

15. A display device according to claim 9, wherein said scanning lines have a low level of Vgl and said discriminating signal lines have a low level of Vdl, where Vgl≧

Vdl.

16. A display device according to claim 9, wherein said scanning lines, said discriminating signal lines, and gradation voltage lines are drawn to both sides of said display device.

17. A display device according to claim 10, wherein:

said first active element has an on current of I1;

said second active element has an on current of I2; and

said first and second active elements are configured to hold I1≧

I2.

18. A display device, comprising:

a plurality of blocks of pixels each of which includes subpixels respectively of three colors, each of said blocks including pixels in a form of a matrix having N rows and M columns;

a subpixel electrode disposed in each said pixel;

a display element disposed in said each subpixel, said element operating according to a voltage on said subpixel electrode;

a scanning line driving circuit for supplying a scanning signal to scanning lines arranged substantially parallel to each other;

a discriminating signal line driving circuit for supplying a discriminating signal to discriminating signal lines arranged substantially vertical to said scanning lines;

holding means for holding in said pixel a discriminating signal from said discriminating line;

a gradation voltage line driving circuit for supplying a gradation voltage to Ma gradation voltage lines for supplying a gradation voltage to each said subpixel, said Ma gradation voltage lines being commonly connected (Ma is an integer;

M≧

Ma≧

2) for said subpixels respectively of three colors of red, green, and blue in a direction of the column;

a circuit for selecting a gradation voltage according to said discriminating signal; and

a switch for applying the gradation voltage selected by said selecting circuit to said subpixel electrode, wherein

said scanning lines, said discriminating signal lines, and gradation voltage lines include three layers of metallic wiring including first, second, and third metallic wiring, and

a coating-type insulation film is formed between said second metallic wiring and said third metallic wiring.