Semi-transmissive display apparatus, method for driving semi-transmissive display apparatus, and electronic system

1. A semi-transmissive display apparatus comprising:

a plurality of signal lines and a plurality of scan lines formed on a first substrate;

a plurality of pixels arranged in rows and columns at intersections of the plurality of signal lines and the plurality of scan lines;

a respective reflective electrode arranged in each of the plurality of pixels;

a transparent electrode formed on a second substrate facing the first substrate;

and a liquid crystal layer between the reflective electrodes and the transparent electrode;

wherein:

the reflective electrodes include openings,

each of the pixels has a memory;

the reflective electrode in each of the pixels is divided into a plurality of sub-electrodes that are weighted in terms of area,

and the display apparatus is configured to perform an area-based grayscale operation to express gray scales based on a combination of the areas of sub-electrodes,

wherein the reflective electrodes are formed on a planarization film with a portion of the planarizing film between reflective electrodes being removed in a transmissive region.

2. The semi-transmissive display apparatus according to claim 1 , wherein a frame inversion driving operation is performed whenever a frame is changed to invert the polarities of signals for driving the pixels in such a way that the polarities are changed to the same polarity for all the pixels.

3. The semi-transmissive display apparatus according to claim 2 , wherein each of the pixels has a memory that stores data.

4. The semi-transmissive display apparatus according to claim 1 , wherein a display mode is a normally black mode.

5. The semi-transmissive display apparatus according to claim 4 , wherein:

the reflective electrode in each of the pixels is divided into three electrodes,

and 2:1 area-based grayscale operation is performed based on a combination of the areas of two of the three electrodes and the area of the remaining one electrode of the three electrodes.

6. The semi-transmissive display apparatus according to claim 5 , wherein the two electrodes and the one electrode have the same size.

7. The semi-transmissive display apparatus according to claim 5 , wherein the two electrodes sandwich the one electrode.

8. The semi-transmissive display apparatus according to claim 5 , wherein the two electrodes are electrically connected to each other.

9. The semi-transmissive display apparatus according to claim 1 , wherein each of the pixels uses a memory liquid crystal material.

10. The semi-transmissive display apparatus according to claim 1 , wherein the signal lines are serpentine wiring lines having bent portions, and the bent portions are positioned at the intersections.

11. The semi-transmissive display apparatus according to claim 1 , wherein the scan lines are serpentine wiring lines having bent portions, and the bent portions are positioned at the intersections.

12. The semi-transmissive display apparatus according to claim 1 , wherein:

during reflective display operation, external light is reflected by the reflective electrodes, and

during transmissive display operation, light passes through the transparent electrode through the opening.

13. The semi-transmissive display apparatus according to claim 1 , wherein:

each reflective electrode has N sub-electrodes,

the grayscale operation expresses 2 N grayscales,

the sub-electrodes have area ratios of 2 0 to 2 N-1 , both inclusive, and

N is a natural number greater than one.

14. A method for driving a semi-transmissive display apparatus including

(a) a plurality of signal lines and a plurality of scan lines formed on a first substrate,

(b) a plurality of pixels arranged in rows and columns at intersections of the plurality of signal lines and the plurality of scan lines, each pixel having a memory,

(c) a respective reflective electrode arranged in each of the plurality of pixels, each reflective electrode comprised of sub-electrodes that are weighted in terms of area,

(d) a transparent electrode formed on a second substrate faced to the first substrate, and

(e) a liquid crystal layer between the reflective electrode and the transparent electrode,

the method comprising:

performing reflective display operation by using the reflective electrodes, performing transmissive display operation by using spaces between the reflective electrodes of the pixels,

and performing an area-based grayscale operation to express display gray scales based on a combination of the areas of the plurality of electrodes

wherein the reflective electrodes are formed on a planarization film with a portion of the planarizing film between reflective electrodes being removed in a transmissive region.

15. An electronic system including a semi-transmissive display apparatus that comprises:

a plurality of signal lines and a plurality of scan lines formed on a first substrate;

a plurality of pixels arranged in rows and columns at intersections of the plurality of signal lines and the plurality of scan lines;

a respective reflective electrode arranged in each of the plurality of pixels;

a transparent electrode formed on a second substrate faced to the first substrate;

and a liquid crystal layer between the reflective electrode and the transparent electrode;

wherein:

the reflective electrode includes openings,

each of the pixels has a memory;

the reflective electrode in each of the pixels is divided into a plurality of sub-electrodes that are weighted in terms of area,

and the display apparatus is configured to perform an area-based grayscale operation to express gray scales based on a combination of the areas of the sub-electrodes,

wherein the reflective electrodes are formed on a planarization film with a portion of the planarizing film between reflective electrodes being removed in a transmissive region.