SEMI-TRANSMISSIVE LIQUID CRYSTAL DISPLAY DEVICE AND ELECTRONIC APPARATUS

• US 20150355493A1
• Filed: 08/19/2015
• Published: 12/10/2015
• Est. Priority Date: 07/18/2012
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: TAMAKI, Masaya, MAEDA, Kazuyuki
• Granted Patent: US 9,436,047 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02F 1/133357 Planarisation layers
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 1/134336 Matrix
• CPC Class Codes: G02F 1/134345 Subdivided pixels, e.g. for grey scale or redundancy
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/123 pixel
• CPC Class Codes: G02F 2413/02 Number of plates being 2
• CPC Class Codes: G02F 2413/04 Number of plates greater than or equal to 4
• CPC Class Codes: G02F 2413/06 Two plates on one side of the LC cell
• CPC Class Codes: G09G 2300/0456 with a reflective area and a transmissive area combined in one pixel, such as in transflectance pixels

Abstract

According to an aspect, a semi-transmissive liquid crystal display device includes a plurality of pixels arranged in a matrix, a plurality of reflective electrodes, a counter electrode facing the reflective electrode, and a liquid crystal layer. The reflective electrodes are provided for each of the pixels, and each of them includes a plurality of electrodes, with a combination of the areas of which area coverage modulation is performed by using n bits. The electrodes are configured such that a ratio of the sum of the perimeter(s) of electrode(s) corresponding to each bit of the n bits satisfies 1:2: . . . :2ⁿ⁻¹. The liquid crystal layer is provided between the reflective electrode and the counter electrode. The semi-transmissive liquid crystal display device is configured to carry out reflective display using the reflective electrode and carry out transmissive display using at least a space of the reflective electrode between the pixels.

Claims

1. A semi-transmissive liquid crystal display device comprising:

a plurality of pixels arranged in a matrix;

a plurality of reflective electrode groups provided for each of the pixels, each of the reflective electrode groups including one or more reflective electrodes, with a combination of the areas of the reflective electrode groups being used to perform area coverage modulation using n bits, where n is an integer equal to or more than 2, each reflective electrode group corresponding to one of the n bits, the reflective electrode groups being configured such that a ratio of the sum of the perimeters of the reflective electrodes in each reflective electrode group corresponding to each bit of the n bits satisfies 1;

2;

. . . ;

2<sup>n−

1</sup>,

a counter electrode facing the plurality of reflective electrode groups; and

a liquid crystal layer provided between the reflective electrode groups and the counter electrode,

wherein the semi-transmissive liquid crystal display device is configured to

carry out reflective display using the reflective electrodes, and

carry out transmissive display using at least a space of the reflective electrodes between the pixels,

wherein the reflective electrodes are arranged such that luminance and gradation change in proportion to each other, and wherein

a gap between reflective electrodes adjacent to each other in one of the pixels is larger than a gap between reflective electrodes of two pixels adjacent to each other in a column direction.

3. The semi-transmissive liquid crystal display device according to claim 1, wherein

the reflective electrodes corresponding to a bit higher than the least significant bit are arranged symmetrically with respect to one or more of the reflective electrodes corresponding to the least significant bit.

4. The semi-transmissive liquid crystal display device according to claim 1, wherein

the reflective electrodes include a first reflective electrode, a second reflective electrode, and a third reflective electrode,

the reflective electrode groups being configured to perform the area coverage modulation by using 2 bits with an area ratio of 2:

1 with a combination of the areas of the first and second reflective electrodes with the third reflective electrode, and

the first and second reflective electrodes are arranged adjacent to each other and electrically connected on a same plane, and first reflective electrode is adjacent to the third reflective electrode.

5. The semi-transmissive liquid crystal display device according to claim 4, further comprising

a conductor formed of a same material as that of the first and second reflective electrodes, the conductor electrically connecting the two reflective electrodes on the plane, wherein

the first and second reflective electrodes and the conductor are integrally formed.

6. The semi-transmissive liquid crystal display device according claim 1, wherein

the reflective electrodes have a same shape and a same size.

7. The semi-transmissive liquid crystal display device according to 1, wherein

two or more of the reflective electrodes corresponding to the same bit are electrically connected to one another.

8. The semi-transmissive liquid crystal display device according to claim 1, wherein

a gap between a reflective electrode corresponding to a lower bit and an adjacent reflective electrode thereof in one of the pixels is larger than a gap between a reflective electrode corresponding to a higher bit and an adjacent reflective electrode thereof in the pixel.

9. The semi-transmissive liquid crystal display device according to claim 1, wherein

parts of color filters included in the pixels adjacent to each other in a row direction overlap with each other.

10. The semi-transmissive liquid crystal display device according to claim 1, further comprising

a scattering layer for scattering light to a side of a traveling direction of light reflected by the reflective electrode than the liquid crystal layer.

11. The semi-transmissive liquid crystal display device according to claim 1, wherein

the semi-transmissive liquid crystal display device has a display mode of a normally black mode.

12. The semi-transmissive liquid crystal display device according to claim 1, wherein the pixels have a memory function.

13. The semi-transmissive liquid crystal display device according to claim 12, wherein the pixels comprise a memory that stores therein data.

14. The semi-transmissive liquid crystal display device according to claim 13, wherein the pixels are provided with memory liquid crystal.

2. A semi-transmissive liquid crystal display device comprising:

a plurality of pixels arranged in a matrix;

a plurality of reflective electrode groups provided for each of the pixels, each of the reflective electrode groups including one or more reflective electrodes, with a combination of the areas of the reflective electrode groups being used to perform area coverage modulation using n bits, where n is an integer equal to or more than 2, each reflective electrode group corresponding to one of the n bits, the reflective electrode groups being configured such that a ratio of the sum of the perimeters of the reflective electrodes in each reflective electrode group corresponding to each bit of the n bits satisfies 1;

2;

. . . ;

2<sup>n−

1</sup> in an opening of the pixel,

a counter electrode facing the plurality of reflective electrode groups; and

a liquid crystal layer provided between the reflective electrode groups and the counter electrode,

wherein the semi-transmissive liquid crystal display device is configured to

carry out reflective display using the reflective electrodes, and

carry out transmissive display using at least a space of the reflective electrodes between the pixels,

wherein the reflective electrodes are arranged such that luminance and gradation change in proportion to each other, and

wherein a gap between reflective electrodes adjacent to each other in one of the pixels is larger than a gap between reflective electrodes of two pixels adjacent to each other in a column direction.