Reflection type liquid crystal display

• US 6,686,981 B2
• Filed: 09/16/1999
• Issued: 02/03/2004
• Est. Priority Date: 09/16/1998
• Status: Expired due to Term

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Ogawa, Shinji, Noritake, Kazuto
• Primary Examiner(s): Parker, Kenneth
• Application Number:
  US09/397,976
• Publication Number:
  US 20010046013A1
• Time in Patent Office: 1,601 Days
• Field of Search: 349/113, 349/129, 349/112
• US Class Current: 349/113
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133541 Circular polarisers
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/133562 on the viewer side
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/13712 the liquid crystal having negative dielectric anisotropy
• CPC Class Codes: G02F 2413/01 Number of plates being 1

Abstract

A reflection type liquid crystal display comprises first and second substrates disposed facing each other and holding a liquid crystal exhibiting a negative dielectric constant anisotropy between them, the first substrate (10) has on the side of its surface facing the second substrate a TFT as a switching element, a reflective display electrode (50) formed of a conductive reflective material and connected to the TFT and a vertical alignment film for vertically aligning the liquid crystal molecules. The second substrate (30) has on the side facing the first substrate a counter electrode (33) including an alignment control window (36) for controlling the alignment of the liquid crystal molecules and an alignment film. The second substrate (30) has on the viewing side of the display, the side of its surface not facing the first substrate, a phase plate (44) and a polarizer (45) forms. A light diffusing layer is formed on the side of the second substrate facing or not facing the first substrate. With this configuration, the display device when viewed from the viewing side is free of the occurrence of parallax and provides a wide viewing angle.

Claims

1. A reflection type liquid crystal display comprising:

first and second substrates disposed facing each other and holding therebetween liquid crystal molecules exhibiting a negative dielectric constant anisotropy;

a switching element, a reflective display electrode formed of a conductive reflective material and connected to said switching element, and a first alignment film to align said liquid crystal molecules, disposed on a side of said first substrate facing said second substrate;

a counter electrode having an alignment control window for controlling said alignment of said liquid crystal molecules and a second alignment film, disposed on a side of said second substrate facing said first substrate;

a phase plate and a polarizer on a side of said second substrate not facing said first substrate; and

a light diffusing layer provided on a side of said second substrate facing said first substrate.

2. A reflection type liquid crystal display according to claim 1, wherein said light diffusing layer is provided between said counter electrode and said second substrate.

3. A reflection type liquid crystal display according to claim 2, wherein color filters are provided at the side of said second substrate facing said first substrate, corresponding to said reflective display electrode, and said light diffusing layer is provided between said color filters and said counter electrode.

4. A reflection type liquid crystal display according to claim 3, further comprising a protective film disposed between said light diffusing layer and said color filters.

5. A reflection type liquid crystal display according to claim 1, wherein said alignment control window is formed at a position corresponding to said reflective display electrode.

6. A reflection type liquid crystal display according to claim 1, wherein said second alignment film is formed over a whole surface of said counter electrode.

7. A reflection type liquid crystal display according to claim 1, wherein the light diffusing layer is formed on a protective film formed on the side of said second substrate facing said first substrate and below the counter electrode.

8. A reflection type liquid crystal display comprising:

first and second substrates disposed facing each other and holding liquid crystal molecules exhibiting a negative dielectric constant anisotropy therebetween;

a switching element, a reflective display electrode formed of a conductive reflective material and connected to said switching element, and a first alignment film to align said liquid crystal molecules, disposed on a side of said first substrate facing said second substrate;

a counter electrode having an alignment control window for controlling said alignment of said liquid crystal molecules and a second alignment film, disposed on a side of said second substrate facing said first substrate;

a light diffusing layer provided on a side of said second substrate facing said first substrate; and

a phase plate and a polarizer on a side of said second substrate not facing said first substrate, wherein the side of said second substrate not facing said first substrate is a viewing side of said display.

9. A reflection type liquid crystal display according to claim 8, wherein a light diffusing layer is formed on the side of said second substrate which faces or does not face said first substrate.

10. A reflection type liquid crystal display according to claim 9, wherein color filters are provided at the side of said second substrate facing said first substrate, corresponding to said reflective display electrode, and said light diffusing layer is provided between said color filters and said counter electrode.

11. A reflection type liquid crystal display according to claim 10, further comprising a protective film disposed between said light diffusing layer and said color filters.

12. A reflection type liquid crystal display according to claim 8, wherein said alignment control window is formed at a position corresponding to said reflective display electrode.

13. A reflection type liquid crystal display according to claim 8, wherein said second alignment film is formed over a whole surface of said counter electrode.