Liquid crystal display device and electronic apparatus

Abstract

A liquid crystal display device includes a first substrate and a second substrate, a liquid crystal layer between the first and second substrates, and an alignment layer between the liquid crystal layer and at least one of the substrates. The liquid crystal layer contains liquid crystal molecules having a negative anisotropy of dielectric constant. The alignment layer aligns the liquid crystal molecules perpendicular to the substrate. The liquid crystal display device further includes pixels. Each pixel includes a plurality of subpixels expressing different colors. Each subpixel includes a stepped layer therein such that the stepped layer is disposed between the liquid crystal layer and at least one of the substrates. The stepped layer defines a first region and a second region in the subpixel. The thickness of the liquid crystal layer is relatively thick in the first region and relatively thin in the second region. The area ratio of the first region depends on a color expressed by the subpixel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.

FIGS. 1A and 1B are diagrams showing the entire structure of a liquid crystal display device according to a first embodiment of the invention.

FIG. 2 is a circuit diagram of the liquid crystal display device.

FIG. 3A is a plan view of one pixel of the liquid crystal display device.

FIG. 3B is a cross-sectional view at the line IIIB-IIIB of FIG. 3A.

FIGS. 4A to 4C are schematic plan views showing other stepped structures.

FIG. 5A is a plan view of one pixel of a liquid crystal display device in accordance with a second embodiment of the invention.

FIG. 5B is a cross-sectional view at the line VB-VB of FIG. 5A.

FIG. 6 is a perspective view illustrating an electronic apparatus.

Claims

1. A liquid crystal display device comprising: a first substrate and a second substrate;a liquid crystal layer between the first and second substrates, the liquid crystal layer containing liquid crystal molecules having a negative anisotropy of dielectric constant; andan alignment layer between the liquid crystal layer and at least one of the substrates, the alignment layer controlling the liquid crystal molecules to be aligned perpendicular to the substrate,the liquid crystal display device further including pixels, each pixel including a plurality of subpixels expressing different colors,each subpixel including a stepped layer therein such that the stepped layer is disposed between the liquid crystal layer and at least one of the substrates,the stepped layer defining a first region and a second region in the subpixel, the thickness of the liquid crystal layer being relatively thick in the first region and relatively thin in the second region, the area ratio of the first region depending on a color expressed by the subpixel.

2. The device according to claim 1, wherein the area ratio of the first region in the subpixel is larger as the wavelength of the color expressed by the subpixel is longer.

3. The device according to claim 1, further comprising: a plurality of electrodes on respective surfaces of the first and second substrates close to the liquid crystal layer, the electrodes driving the liquid crystal molecules, whereineach subpixel includes the electrode on at least one of the substrates,the electrode includes a plurality of island portions and a linking portion electrically connecting the adjacent island portions, andthe linking portion is two-dimensionally superimposed on a boundary region of the stepped layer.

4. The device according to claim 3, further comprising: a light-shielding layer on at least one of the first and second substrates, whereinthe light-shielding layer is two-dimensionally superimposed on the boundary region of the stepped layer in the subpixel.

5. A liquid crystal display device comprising: a first substrate and a second substrate;a liquid crystal layer between the first and second substrates, the liquid crystal layer containing liquid crystal molecules having a negative anisotropy of dielectric constant; andan alignment layer between the liquid crystal layer and at least one of the substrates, the alignment layer controlling the liquid crystal molecules to be aligned perpendicular to the substrate,the liquid crystal display device further including pixels, each pixel including a plurality of subpixels, each subpixel having a transmissive display area for transmissive display and a reflective display area for reflective display,the subpixel including a stepped layer therein such that the stepped layer is disposed between the liquid crystal layer and at least one of the substrates,the stepped layer defining a first region and a second region in the transmissive display area of the subpixel, the thickness of the liquid crystal layer being relatively thick in the first region and relatively thin in the second region, the area ratio of the first region depending on a color expressed by the subpixel.

6. The device according to claim 5, wherein the subpixel includes a thickness adjusting layer therein such that the thickness adjusting layer is disposed between the liquid crystal layer and at least one of the substrates, the thickness adjusting layer making the thickness of the liquid crystal layer in the reflective display area less than that in the transmissive display area,the stepped layer is disposed in the transmissive display area, andthe stepped layer and the thickness adjusting layer are made of the same material.

7. The device according to claim 5, wherein the area ratio of the first region in the transmissive display area of the subpixel is larger as the wavelength of the color expressed by the subpixel is longer.

8. The device according to claim 5, further comprising: a plurality of electrodes on respective surfaces of the first and second substrates close to the liquid crystal layer, the electrodes driving the liquid crystal molecules, whereineach subpixel includes the electrode on at least one of the substrates,the electrode includes a plurality of island portions and linking portions each electrically connecting the adjacent island portions, andthe linking portion is two-dimensionally superimposed on a boundary region of the stepped layer.

9. The device according to claim 5, further comprising: a light-shielding layer on at least one of the first and second substrates, whereinthe light-shielding layer is two-dimensionally superimposed on the boundary region of the stepped layer in the subpixel.

10. The device according to claim 5, wherein the thickness of the liquid crystal layer in the second region is approximately equal to that in the reflective display area.

11. An electronic apparatus comprising the liquid crystal display device according to claim 1.