Transflective LCD unit

• US 8,508,699 B2
• Filed: 11/10/2008
• Issued: 08/13/2013
• Est. Priority Date: 11/08/2007
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd.
• Original Assignee: NLT Technologies, Ltd.
• Inventors: Mori, Kenichi, Sakamoto, Michiaki, Nagai, Hiroshi
• Primary Examiner(s): Merlin, Jessica M
• Application Number:
  US12/268,303
• Publication Number:
  US 20090122211A1
• Time in Patent Office: 1,737 Days
• Field of Search: 349/113, 349/114, 349/129, 349/141
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133555 Transflectors
• 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 1/134318 having a patterned common electrode
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]

Abstract

A transflective LCD unit includes a liquid crystal (LC) layer: first and second substrates sandwiching therebetween the LC layer to define an array of pixels each including a reflective area and a transmissive area; an electrode assembly for driving the LC layer such that the LC layer in the reflective area is driven in a longitudinal-electric-field mode and the LC layer in the transmissive area is driven in a lateral-electric-field mode; and a reverse-tilt control member for controlling a reverse tilt area in which a reverse tilt of LC molecules occurs near the boundary between the reflective area and the transmissive area.

Claims

1. A transflective liquid crystal display (LCD) unit comprising:

a liquid crystal (LC) layer;

first and second substrates sandwiching therebetween said LC layer to define an array of pixels in said LC layer, said pixels each including a reflective area and a transmissive area;

an electrode assembly for driving said LC layer such that said LC layer in said reflective area is driven in a longitudinal-electric-field mode and said LC layer in said transmissive area is driven in a lateral-electric-field mode; and

a reverse-tilt control member disposed in a vicinity of a boundary area formed between said reflective area and said transmissive area for controlling a reverse tilt area in which a reverse tilt of LC molecules occurs in said LC layer,

wherein said electrode assembly comprises;

a reflective-area pixel electrode,

a transmissive area pixel electrode and a transmissive-area common electrode formed on said first substrate,

a reflective-area common electrode formed on said second substrate, and

a retardation film disposed at a light-incident side in the reflective area which converts linearly-polarized light incident onto the liquid crystal display unit into circularly-polarized light, and converts counter-circularly-polarized light converted by being reflected by a reflection film disposed at a light-reflection side in the reflective area from the circularly-polarized light, into linearly-polarized light having an optical axis perpendicular to an optical axis of the linearly-polarized light incident onto the liquid crystal display unit,

wherein said reflective area is formed by an area on the reflective-area pixel electrode where the reflective-area pixel electrode and the reflective-area common electrode are facing each other,

said transmissive area is formed by an area defined by an outer edge of the transmissive-area common electrode,

said reflective-area common electrode has an extension protruding toward said transmissive area across said boundary area, and said reverse-tilt control member is configured by the protruding portion of said reflective-area common electrode, thereby rendering said reverse tilt generated within said boundary area being close to the transmissive area, and

said reflective-area common electrode which has the protruding portion as said reverse-tilt control member is configured to be in parallel to the retardation film and attached to the retardation film.

2. The transflective LCD unit according to claim 1, wherein said reverse-tilt control member restricts said reverse tilt area within an area of said LC layer that is driven in a lateral-electric-field mode.

3. The transflective LCD unit according to claim 1, wherein said reflective-area common electrode and said transmissive-area common electrode are applied with different signals.

4. A terminal device including the transflective LCD unit according to claim 1.