TRANSFLECTIVE LIQUID-CRYSTAL-DISPLAY DEVICE

• US 20100328592A1
• Filed: 08/31/2010
• Published: 12/30/2010
• Est. Priority Date: 03/07/2006
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd.
• Original Assignee: NLT Technologies, Ltd.
• Inventors: Ikeno, Hidenori, Naka, Kenichirou, Mori, Kenichi, Nagai, Hiroshi, Sakamoto, Michiaki
• Granted Patent: US 8,502,941 B2
• Time in Patent Office: Days
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133565 inside the LC elements, i.e. between the cell substrates
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133631 with a spatial distribution of the retardation value
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 2413/03 Number of plates being 3
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127

Abstract

A LCD device has a LC layer sandwiched between a TFT substrate and a counter substrate, first and second polarizing films, a first λ/2 film between the first polarizing film and the counter substrate, and a second λ/2 film between the second polarizing film and the TFT substrate. Angle θ1 between the direction of the optical axis of the LC layer and the polarized direction of the light entering the LC layer satisfies the relationship: 0 degree<θ1<45 degrees. The resultant LCD device has lower leakage light and coloring.

Claims

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

a liquid crystal (LC) layer defining a plurality of pixels each having a transmissive area and a reflective area, at least said transmissive area operating in a lateral-electric-field mode;

first and second polarizing films sandwiching therebetween said LC layer, said first polarizing film being effective common to said transmissive area and said reflective area, said second polarizing film being effective only to said transmissive area; and

a retardation film sandwiched between said first polarizing film and said LC layer.

2. The transflective LCD device according to claim 1, wherein each of said pixels includes a pixel electrode driven by a pixel data signal supplied in common to said transmissive area and said reflective area, a first common electrode driven by a first common signal supplied in common to said reflective areas of said plurality of pixels, and a second common electrode driven by a second common signal supplied in common to said transmissive areas of said plurality of pixels.

3-39. -39. (canceled)

40. A transflective liquid-crystal-display (LCD) device comprising:

a liquid crystal (LC) layer defining a plurality of pixels each having a transmissive area and a reflective area, at least said transmissive area operating in a lateral-electric-field mode;

first and second polarizing films sandwiching therebetween said LC layer, said first polarizing film being effective common to said transmissive area and said reflective area, said second polarizing film being effective only to said transmissive area; and

a retardation film sandwiched between said first polarizing film and said LC layer,

wherein said retardation film acts as a ½

-wavelength film at a wavelength of 550 nm.

42. A transflective liquid-crystal-display (LCD) device comprising:

a liquid crystal (LC) layer defining a plurality of pixels each having a transmissive area and a reflective area, at least said transmissive area operating in a lateral-electric-field mode;

first and second polarizing films sandwiching therebetween said LC layer, said first polarizing film being effective common to said transmissive area and said reflective area, said second polarizing film being effective only to said transmissive area; and

a retardation film sandwiched between said first polarizing film and said LC layer,

wherein each of said pixels includes a pixel electrode driven by a pixel data signal supplied in common to said transmissive area and said reflective area, a first common electrode drive by a first common signal supplied in common to said reflective areas of said plurality of pixels, and a second common electrode driven by a second common signal supplied in common to said transmissive areas of said plurality of pixels,

wherein an angle θ

1 between an optical axis of said LC layer in said transmissive area upon display of a dark image and a polarized direction of light incident onto said LC layer satisfies the following relationship;

zero degree<

θ

1<

45 degrees.

43. The transflective LCD device according to claim 42, wherein said angle θ

1 satisfies the following relationship;

zero degree<

θ

1≦

22.5 degrees.

44. A transflective liquid-crystal-display (LCD) device comprising:

a liquid crystal (LC) layer defining a plurality of pixels each having a transmissive area and a reflective area, at least said transmissive area operating in a lateral-electric-field mode;

first and second polarizing films sandwiching therebetween said LC layer, said first polarizing film being effective common to said transmissive area and said reflective area, said second polarizing film being effective only to said transmissive area; and

a retardation film sandwiched between said first polarizing film and said LC layer,

wherein each of said pixels includes a pixel electrode driven by a pixel data signal supplied in common to said transmissive area and said reflective area, a first common electrode driven by a first common signal supplied in common to said reflective areas of said plurality of pixels, and a second common electrode driven by a second common signal supplied in common to said transmissive areas of said plurality of pixels,

wherein an angle θ

2 between an optical axis of said LC layer in said reflective area upon display of a dark image and a polarized direction of light incident onto said LC layer satisfies the following relationship;

θ

2=45 degrees.

45. A transflective liquid-crystal-display (LCD) device comprising:

a liquid crystal (LC) layer defining a plurality of pixels each having a transmissive area and a reflective area, at least said transmissive area operating in a lateral-electric-field mode;

first and second polarizing films sandwiching therebetween said LC layer, said first polarizing film being effective common to said transmissive area and said reflective area, said second polarizing film being effective only to said transmissive area; and

a retardation film sandwiched between said first polarizing film and said LC layer,

wherein each of said pixels includes a pixel electrode driven by a pixel data signal supplied in common to said transmissive area and said reflective area, a first common electrode driven by a first common signal supplied in common to said reflective areas of said plurality of pixels, and a second common electrode driven by a second common signal supplied in common to said transmissive areas of said plurality of pixels,

wherein a polarized direction of light incident onto said second polarizing film and an optical absorption axis of said second polarizing film are aligned with each other upon display of a dark image.

46. A transflective liquid-crystal-display (LCD) device comprising:

a liquid crystal (LC) layer defining a plurality of pixels each having a transmissive area and a reflective area, at least said transmissive area operating in a lateral-electric-field mode;

first and second polarizing films sandwiching therebetween said LC layer, said first polarizing film being effective common to said transmissive area and said reflective area, said second polarizing film being effective only to said transmissive area;

a retardation film sandwiched between said first polarizing film and said LC layer; and

another ½

wavelength film between said second polarizing film and said LC layer,

wherein each of said pixels includes a pixel electrode driven by a pixel data signal supplied in common to said transmissive area and said reflective area, a first common electrode driven by a first common signal supplied in common to said reflective areas of said plurality of pixels, and a second common electrode driven by a second common signal supplied in common to said transmissive areas of said plurality of pixels.

47. The transflective LCD device according to claim 46, wherein an angle θ

1 between an optical axis of said LC layer in said transmissive area upon display of a dark image and a polarized direction of light incident onto said LC layer is zero degree, further comprising a retardation film sandwiched between said another ½

wavelength film and said LC layer.

48. A transflective liquid-crystal-display (LCD) device comprising:

a liquid crystal (LC) layer defining a plurality of pixels each having a transmissive area and a reflective area, at least said transmissive area operating in a lateral-electric-field mode;

first and second polarizing films sandwiching therebetween said LC layer, said first polarizing film being effective common to said transmissive area and said reflective area, said second polarizing film being effective only to said transmissive area; and

a retardation film sandwiched between said first polarizing film and said LC layer,

wherein each of said pixels includes a pixel electrode driven by a pixel data signal supplied in common to said transmissive area and said reflective area, a first common electrode driven by a first common signal supplied in common to said reflective areas of said plurality of pixels, and a second common electrode driven by a second common signal supplied in common to said transmissive areas of said plurality of pixels,

wherein said LC layer includes homogeneously-oriented liquid crystal.

49. A transflective liquid-crystal-display (LCD) device comprising:

a liquid crystal (LC) layer defining a plurality of pixels each having a transmissive area and a reflective area, at least said transmissive area operating in a lateral-electric-field mode;

first and second polarizing films sandwiching therebetween said LC layer, said first polarizing film being effective common to said transmissive area and said reflective area, said second polarizing film being effective to said transmissive area; and

a retardation film sandwiched between said first polarizing film and said LC layer,

wherein each of said pixels includes a pixel electrode driven by a pixel data signal supplied in common to said transmissive area and said reflective area, a first common electrode driven by a first common signal supplied in common to said reflective areas of said plurality of pixels, and a second common electrode driven by a second common signal supplied in common to said transmissive areas of said plurality of pixels.