Color liquid crystal apparatus

• US 5,724,112 A
• Filed: 06/16/1995
• Issued: 03/03/1998
• Est. Priority Date: 03/28/1994
• Status: Expired due to Term

• Current Assignee: Ortus Technology Co., Ltd. (TOPPAN Holdings, Inc.)
• Original Assignee: Casio Computer Company Limited
• Inventors: Yoshida, Tetsushi, Aoki, Hisashi, Kikuchi, Zenta
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): TON, MINH TOAN T
• Application Number:
  US08/491,088
• Time in Patent Office: 991 Days
• Field of Search: 359/63, 359/73, 359/93, 359/71, 359/59, 359/68, 349/99, 349/117, 349/119, 349/42, 349/113, 349/114, 349/121
• US Class Current: 349/117
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence
• CPC Class Codes: G02F 1/1396 the liquid crystal being selectively controlled between a twisted state and a non-twisted state, e.g. TN-LC cell G02F1/141 takes precedence
• CPC Class Codes: G02F 2203/34 Colour display without the use of colour mosaic filters

Abstract

A color liquid crystal display device including a transparent first substrate having an inner surface and at least one transparent electrode formed thereon, and an insulating second substrate having an inner surface arranged to oppose the inner surface of the first substrate and at least one electrode formed on the inner surface of the second substrate. A liquid crystal layer is sandwiched between the inner surfaces of the first and second substrates and has a predetermined initial aligned state. A polarizing member is arranged on a first substrate side of the liquid crystal layer, and at least one retardation plate is provided for coloring light which emerges from the liquid crystal display. The retardation plate is arranged between the liquid crystal layer and the polarizing member such that an optical axis of the retardation plate with respect to a transmission axis of the polarizing member is not parallel to or perpendicular to the transmission axis. A reflecting member is arranged on a liquid crystal layer side of the second substrate.

Claims

1. A color liquid crystal display device comprising:

a transparent first substrate having an inner surface and at least one transparent electrode formed thereon;

an insulating second substrate having an inner surface arranged to oppose the inner surface of said first substrate and at least one electrode formed on the inner surface of said second substrate;

a liquid crystal layer sandwiched between the inner surfaces of said first and second substrates and having a predetermined initial aligned state;

a polarizing member arranged on a first substrate side of said liquid crystal layer;

at least one retardation plate for coloring light which emerges from the liquid crystal display, said retardation plate being arranged between said liquid crystal layer and said polarizing member such that an optical axis of said retardation plate with respect to a transmission axis of said polarizing member is not parallel to or perpendicular to the transmission axis; and

a reflecting member arranged on a liquid crystal layer side of said second substrate;

wherein the inner surface of one of said first and second substrates includes a plurality of pixel electrodes and a plurality of active elements respectively corresponding to said plurality of pixel electrodes, said pixel electrodes and said active elements being arranged in a matrix on the inner surface of said one of said first and second substrates, and the inner surface of the other substrate includes at least one counter electrode formed thereon; and

wherein molecules of said liquid crystal layer are twisted and aligned at an angle of 90°

, the transmission axis of said polarizing member is about 45°

with respect to an aligning direction of liquid crystal molecules of said liquid crystal layer adjacent to said second substrate, and a phase delay axis of said retardation plate is about 140°

with respect to the aligning direction of the liquid crystal molecules of said liquid crystal layer adjacent to said second substrate.

2. An apparatus according to claim 1, wherein said plurality of pixel electrodes and said plurality of active elements respectively corresponding to said plurality of pixel electrodes are formed on the inner surface of said second substrate, and said pixel electrodes also serve as said reflecting member.

3. An apparatus according to claim 1, wherein said plurality of pixel electrodes and said active elements respectively corresponding to said plurality of pixel electrodes are formed on the inner surface of said first substrate, and said at least one counter electrode also serves as said reflecting member.

4. An apparatus according to claim 1, wherein a product Δ

n·

d of a refractive index anisotropy Δ

n and a film thickness d of a liquid crystal of said liquid crystal layer is about 1,000 nm, and a retardation value of said retardation plate is about 600 nm.

5. An apparatus according to claim 1, wherein said plurality of active elements arranged on the inner surface of said second substrate are covered with an insulating film having a substantially even surface, and said pixel electrodes are arranged on said insulating film so that at least one part of said pixel electrodes overlap said active elements and are respectively connected to corresponding ones of said active elements.

6. An apparatus according to claim 5, wherein said reflecting member is arranged on said insulating film covering said active elements, and said pixel electrodes are arranged on a liquid crystal layer side of said reflecting member.

7. An apparatus according to claim 5, further comprising a second polarizing member arranged between said reflecting member and said pixel electrodes.

8. An apparatus according to claim 1, further comprising capacitor electrodes arranged on a second substrate side of said pixel electrodes to oppose said pixel electrodes via an insulating film.

9. An apparatus according to claim 1, wherein a light-scattering surface is formed on a front surface of said reflecting member.

10. An apparatus according to claim 1, wherein a light-scattering surface is formed on a front surface of said polarizing member.

11. An apparatus according to claim 10, wherein the light-scattering surface on the front surface of said polarizing member has a haze value which falls within a range of 9 to 14%.

12. An apparatus according to claim 1, wherein a polarizing film is arranged on a front surface side of said reflecting member arranged on said second substrate of said liquid crystal cell, and a transparent electrode is arranged on said polarizing film.

13. An apparatus according to claim 1, wherein at least one light-scattering member is arranged on an optical path through which light incident on said display device emerges.

14. An apparatus according to claim 1, wherein said liquid crystal layer includes liquid crystal molecules which are twisted and aligned homogeneously in said predetermined initial aligned state.

15. A color liquid crystal display device comprising:

a transparent first substrate having an inner surface and at least one transparent electrode formed thereon;

an insulating second substrate having an inner surface arranged to oppose said first substrate and having at least one electrode formed on the inner surface of said second substrate opposing said at least one transparent electrode formed on the inner surface of said first substrate;

a liquid crystal layer sandwiched between said first and second substrates and having a predetermined initial aligned state;

a first polarizing member arranged on a first substrate side of said liquid crystal layer such that a transmission axis of said polarizing member is shifted at a predetermined angle with respect to a liquid crystal molecule aligning direction on the first substrate side of said liquid crystal layer so as not to be parallel to or perpendicular to the liquid crystal molecule aligning direction;

at least one retardation plate for coloring light which emerges from the liquid crystal display, said retardation plate being arranged between said liquid crystal layer and said polarizing member such that a retardation axis of said retardation plate is shifted by a predetermined angle with respect to a transmission axis of said polarizing member so as not to be parallel to or perpendicular to the transmission axis of said first polarizing member;

a semitransparent reflecting member arranged on a liquid crystal layer side of said second substrate; and

a second polarizing member arranged on a second substrate side of said semitransparent reflecting member; and

wherein said semitransparent reflecting member includes a mirror surface having a large number of small holes.

16. An apparatus according to claim 15, wherein said at least one transparent electrode formed on the inner surface of said first substrate comprises a plurality of pixel electrodes, a plurality of active elements respectively corresponding to said plurality of pixel electrodes are provided on the inner surface of said first substrate, said pixel electrodes and said active elements being arranged in a matrix, and said at least one electrode formed on the inner surface of said second substrate comprises at least one counter electrode.

17. An apparatus according to claim 16, wherein said plurality of active elements arranged on the inner surface of said second substrate are covered with an insulating film having a substantially even surface, and said pixel electrodes are arranged on said insulating film so that at least one part of said pixel electrodes overlap, said active elements and are respectively connected to corresponding ones of said active elements.

18. An apparatus according to claim 15, wherein said at least one transparent electrode formed on the inner surface of said first substrate comprises a plurality of pixel electrodes, a plurality of active elements respectively corresponding to said plurality of pixel electrodes are provided on the inner surface of said first substrate, said pixel electrodes and said active elements being formed in a matrix, and said at least one electrode formed on the inner surface of said second substrate comprises at least one pixel electrode which also serves as said semitransparent reflecting member.

19. An apparatus according to claim 15, wherein said at least one transparent electrode formed on the inner surface of said first substrate comprises a plurality of pixel electrodes, a plurality of active elements respectively corresponding to said plurality of pixel electrodes are provided on the inner surface of said first substrate, said pixel electrodes and said active elements being formed in a matrix, and said at least one electrode formed on the inner surface of said second substrate comprises at least one counter electrode which also serves as said semitransparent reflecting member.

20. An apparatus according to claim 15, wherein molecules of said liquid crystal layer are twisted and aligned at an angle of about 90°

, the transmission axis of said polarizing member is about 170°

with respect to an aligning direction of liquid crystal molecules of said liquid crystal layer adjacent to said second substrate, and the retardation axis of said retardation plate is about 150°

with respect to the aligning direction of the liquid crystal molecules of said liquid crystal layer adjacent to said second substrate.

21. An apparatus according to claim 20, wherein a product Δ

n·

d of a refractive index anisotropy Δ

n and a film thickness d of a liquid crystal of said liquid crystal layer is about 980 nm, and a retardation value of said retardation plate is about 370 nm.

22. A color liquid crystal display device comprising:

a transparent first substrate having an inner surface and at least one transparent electrode formed thereon;

an insulating second substrate having an inner surface arranged to oppose said first substrate and having at least one electrode formed on the inner surface of said second substrate opposing said at least one transparent electrode formed on the inner surface of said first substrate;

a liquid crystal layer sandwiched between said first and second substrates and having a predetermined initial aligned state;

a first polarizing member arranged on a first substrate side of said liquid crystal layer such that a transmission axis of said polarizing member is shifted at a predetermined angle with respect to a liquid crystal molecule aligning direction on the first substrate side of said liquid crystal layer so as not to be parallel to or perpendicular to the liquid crystal molecule aligning direction;

at least one retardation plate for coloring light which emerges from the liquid crystal display, said retardation plate being arranged between said liquid crystal layer and said polarizing member such that a retardation axis of said retardation plate is shifted by a predetermined angle with respect to a transmission axis of said polarizing member so as not to be parallel to or perpendicular to the transmission axis of said first polarizing member;

a semitransparent reflecting member arranged on a liquid crystal layer side of said second substrate; and

a second polarizing member arranged on a second substrate side of said semitransparent reflecting member; and

wherein molecules of said liquid crystal layer are twisted and aligned at an angle of about 90°

, the transmission axis of said polarizing member is about 170°

with respect to an aligning direction of liquid crystal molecules of said liquid crystal layer adjacent to said second substrate, and the retardation axis of said retardation plate is about 150°

with respect to the aligning direction of the liquid crystal molecules of said liquid crystal layer adjacent to said second substrate.

23. An apparatus according to claim 22, wherein a product Δ

n·

d of a refractive index anisotrophy Δ

n and a film thickness d of a liquid crystal of said liquid crystal layer is about 980 nm, and a retardation value of said retardation plate is about 370 nm.