Transflective liquid crystal display unit

• US 8,194,211 B2
• Filed: 03/16/2009
• Issued: 06/05/2012
• Est. Priority Date: 03/18/2008
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd.
• Original Assignee: NLT Technologies, Ltd.
• Inventors: Nagai, Hiroshi, Sakamoto, Michiaki, Naka, Kenichirou, Mori, Kenichi
• Primary Examiner(s): Glick, Edward
• Assistant Examiner(s): Nguyen, Sang
• Application Number:
  US12/404,713
• Publication Number:
  US 20090237600A1
• Time in Patent Office: 1,177 Days
• Field of Search: 349/114, 349/113
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133555 Transflectors

Abstract

A LCD unit includes a reflective area and a transmissive area in each pixel, which are driven by respective drive electrode assemblies. A first substrate and a second substrate that sandwich therebetween a LC layer include respective shied films in the boundary area between the reflective area and the transmissive area.

Claims

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

a liquid crystal (LC) cell including a LC layer and first and second substrates sandwiching therebetween said LC layer, said LC cell defining an array of pixels each including a reflective area and a transmissive area, wherein

said LCD is a semi-transmissive type LCD driven by a signal where said transmissive area that is normally black and said reflective area that is normally white are inverted ON-OFF,

said second substrate includes, in said transmissive area, a first electrode assembly that drives said LC layer in said transmissive area, and includes, in said reflective area, a reflection film and

at least a part of a second electrode assembly that drives said LC layer in said reflective area, and said first and second substrates including first and second light shield members, respectively, wherein;

said first drive electrode assembly and said second drive electrode assembly in-plane switch liquid crystal (LC) molecules of said LC layer in said transmissive area and said reflective area, respectively,

said first drive electrode assembly including a first pixel electrode and a first common electrode, which are both transmissive electrodes, said second drive electrode assembly including a second pixel electrode and a second common electrode, which are both reflective electrodes, wherein a sequence of said LC molecules is changed by applying signals between said first pixel electrode and said first common electrode, and said second pixel electrode and said second common electrode, the signals being inverted ON-OFF,

said first light shield member being disposed at a boundary between said reflective area and said transmissive area in said first substrate and the vicinity thereof, so as to suppress light incident from a visually recognized side of said reflective area from being emitted in a direction of said transmissive area, and

said second light shield member being provided at a boundary between said transmissive area and said reflective area on said second substrate and the vicinity thereof, and being provided on a lower layer of said second substrate than said first drive electrode assembly and said second drive electrode assembly so as to suppress light leakage arising from light reflected by said first light shield member, wherein the light reflected by said first light shield member is incident from a backlight through a boundary portion between said transmissive area and said reflective area which is normally white,

wherein said second substrate includes a gate signal line, a first common-electrode line and a drain line that underlies said first pixel electrode and said first common electrode in the transmissive area, said first pixel electrode and said first common electrode are partially overlapped by said gate signal line, said first common-electrode line and said drain line respectively, and

wherein said second light shield member is configured by any one of a stack of said gate signal line and said reflection film, a stack of said first common-electrode line and said reflection film, and a stack of said drain line and said reflection film.

2. The LCD unit according to claim 1, wherein said first and second light shield members are configured by a metallic film having a surface treated for reduction of reflectance or a resin film that includes therein carbon additives, respectively.

3. The LCD unit according to claim 1, wherein said second substrate includes a gate signal line, a common-electrode line and a data signal line that underlie said reflection film, and said second light shield member of said second substrate is configured by a stack of at least two films selected from the group consisting of said reflection film, gate signal line, common-electrode line and data signal line.

4. The LCD unit according to claim 3, wherein said second light shield member of said second substrate includes a stack of said reflection film and gate signal line, a stack of said reflection film and data signal line, or a stack of said reflection film and common-electrode line.

5. The LCD unit according to claim 1, wherein said reflection film underlies said second drive electrode assembly in said second substrate, and said second light shield member of said second substrate underlies said reflection film.

6. The LCD unit according to claim 1, wherein said second light shield member of said second substrate ranges between an edge of said reflection film and a position of said transmissive area which is 4 μ

m or more apart in a direction opposite to said reflective area from an edge of said transparent film nearest to said reflective area.

7. The LCD unit according to claim 1, wherein said second light shield member of said second substrate ranges between an edge of said reflection film and a position of said transmissive area which is 4 μ

m or more apart in a direction opposite to said reflective area from an edge of said transparent film in said transmissive area nearest to said reflective area.