Liquid crystal display

• US 6,297,864 B1
• Filed: 02/09/2000
• Issued: 10/02/2001
• Est. Priority Date: 03/03/1998
• Status: Expired due to Fees

• Current Assignee: Citizen Holdings Co., Ltd. (Citizen Electronics Company Limited)
• Original Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Inventors: Kaneko, Yasushi, Akiyama, Takashi, Ide, Masafumi
• Primary Examiner(s): Parker, Kenneth
• Assistant Examiner(s): VU, QUYNH-NHU HOANG
• Application Number:
  US09/485,393
• Time in Patent Office: 601 Days
• Field of Search: 349/117, 349/119, 349/96, 349/176
• US Class Current: 349/117
• CPC Class Codes: G02F 1/133533 Colour selective polarisers G02F1/1347 takes precedence
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133543 Cholesteric polarisers
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 2201/08 light absorbing layer
• CPC Class Codes: G02F 2203/03 scattering
• CPC Class Codes: G04G 9/0035 constructional

Abstract

A single color liquid crystal display device is made up of a TN liquid crystal cell 7 with about 90° twisted nematic liquid crystals sealed in-between a pair of transparent substrates 1, 2 having respective transparent electrodes 3, 4, a first polarizing film 17 disposed on the visible side of the TN liquid crystal cell 7, and a second polarizing film 18, a retardation film 6 for circularly polarized light, a cholestric liquid crystal polymer sheet 10, a translucent light absorbing member 15 and a backlight 16 disposed successively on a side of the TN liquid crystal cell 7, opposite from the visible side thereof. With such a constitution, display is rendered visible even at night by lighting up the backlight 16, and colored display in a metallic tone can be indicated.

Claims

1. A liquid crystal display device comprising:

a TN liquid crystal cell with about 90°

twisted nematic liquid crystals sealed in-between a pair of transparent substrates having respective transparent electrodes;

a first polarizing film disposed on a visible side of the TN liquid crystal cell; and

a second polarizing film, a retardation film for circularly polarized light, a cholestric liquid crystal polymer sheet, a translucent light absorbing member and a backlight disposed successively on a side of the TN liquid crystal cell, opposite from the visible side thereof.

13. A liquid crystal display device according to claim 1, wherein a luminescence center wavelength of the backlight is deviated by not less than 50 nm from a selected scattering center wavelength of the cholestric liquid crystal polymer sheet.

17. A liquid crystal display device according to claim 1, wherein the backlight has not less than two luminescence center wavelengths, and at least one of the luminescence center wavelengths is deviated by not less than 50 nm from a selected scattering center wavelength of the cholestric liquid crystal polymer sheet.

21. A liquid crystal display device according to claim 1, wherein the second polarizing film is a reflection-type polarizing film.

2. A liquid crystal display device comprising:

an STN liquid crystal cell with 180°

to 270°

twisted nematic liquid crystals sandwiched between a pair of transparent substrates having respective transparent electrodes;

a retardation film disposed on a visible side of the STN liquid crystal cell;

a first polarizing film disposed on an outer side of the retardation film; and

a second polarizing film, a retardation film for circularly polarized light, a cholestric liquid crystal polymer sheet, a translucent light absorbing member and a backlight disposed successively on a side of the STN liquid crystal cell, opposite from the visible side thereof.

3. A liquid crystal display device according to claim 2, wherein the retardation film is a twisted retardation film.

4. A liquid cell display device comprising:

a TN liquid crystal cell with about 90°

twisted nematic liquid crystals sealed in-between a pair of transparent substrates having respective electrodes;

a first polarizing film disposed on a visible side of the TN liquid crystal cell; and

a second polarizing film, a retardation film for circularly polarized light, a cholestric liquid crystal polymer sheet and a backlight disposed successively on a side of the TN liquid crystal cell, opposite from the visible side thereof,

wherein a face of said backlight, opposite to said cholestric liquid crystal polymer sheet, has a function of scattering polarized light.

14. A liquid crystal display device according to claim 4, wherein a luminescence center wavelength of the backlight is deviated by not less than 50 nm from a selected scattering center wavelength of the cholestric liquid crystal polymer sheet.

18. A liquid crystal display device according to claim 4, wherein the backlight has not less than two luminescence center wavelengths, and at least one of the luminescence center wavelengths is deviated by not less than 50 nm from a selected scattering center wavelength of the cholestric liquid crystal polymer sheet.

22. A liquid crystal display device according to claim 4, wherein the second polarizing film is a reflection-type polarizing film.

5. A liquid crystal display device comprising:

an STN liquid crystal cell with 180°

to 270°

twisted nematic liquid crystals sandwiched between a pair of transparent substrates having respective transparent electrodes;

a retardation film disposed on a visible side of the STN liquid crystal cell;

a first polarizing film disposed on an outer side of the retardation film; and

a second polarizing film, a retardation film for circularly polarized light, a cholestric liquid crystal polymer sheet and a backlight disposed successively on a side of the STN liquid crystal cell, opposite from the visible side thereof,

wherein a face of said backlight, opposite to said cholestric liquid crystal polymer sheet, has a function of scattering polarized light.

6. A liquid crystal display device according to claim 5, wherein the retardation film is a twisted retardation film.

7. A liquid crystal display device comprising:

a TN liquid crystal cell with about 90°

twisted nematic liquid crystals sealed in-between a pair of transparent substrates having respective transparent electrodes;

a first polarizing film disposed on a visible side of the TN liquid crystal cell; and

a first retardation film for circularly polarized light, a cholestric liquid crystal polymer sheet, a second retardation film for circularly polarized light, a second polarizing film, a translucent light absorbing member and a backlight disposed successively on a side of the TN liquid crystal cell, opposite from the visible side thereof.

15. A liquid crystal display device according to claim 7, wherein a luminescence center wavelength of the backlight is deviated by not less than 50 nm from a selected scattering center wavelength of the cholestric liquid crystal polymer sheet.

19. A liquid crystal display device according to claim 7, wherein the backlight has not less than two luminescence center wavelengths, and at least one of the luminescence center wavelengths is deviated by not less than 50 nm from a selected scattering center wavelength of the cholestric liquid crystal polymer sheet.

23. A liquid crystal display device according to claim 7, wherein the second polarizing film is a reflection-type polarizing film.

8. A liquid crystal display device comprising:

an STN liquid crystal cell with 180°

to 270°

twisted nematic liquid crystals sandwiched between a pair of transparent substrates having respective transparent electrodes;

a retardation film disposed on a visible side of the STN liquid crystal cell;

a first polarizing film disposed on an outer side of the retardation film; and

a first retardation film for circularly polarized light, a cholestric liquid crystal polymer sheet, a second retardation film for circularly polarized light, a second polarizing film, a translucent light absorbing member and a backlight disposed successively on a side of the STN liquid crystal cell, opposite from the visible side thereof.

9. A liquid crystal display device according to claim 8, wherein the retardation film is a twisted retardation film.

10. A liquid crystal display comprising:

a TN liquid crystal cell with about 90°

twisted nematic liquid crystals sealed in-between a pair of transparent substrates having respective transparent electrodes;

a first polarizing film disposed on a visible side of the TN liquid crystal cell; and

a first retardation film for circularly polarized light, a cholestric liquid crystal polymer sheet, a second retardation film for circularly polarized light, a second polarizing film and a backlight disposed successively on a side of the TN liquid crystal cell, opposite from the visible side thereof,

wherein a face of said backlight, opposite to said second polarizing film, has a function of scattering polarized light.

16. A liquid crystal display device according to claim 10, wherein a luminescence center wavelength of the backlight is deviated by not less than 50 nm from a selected scattering center wavelength of the cholestric liquid crystal polymer sheet.

20. A liquid crystal display device according to claim 10, wherein the backlight has not less than two luminescence center wavelengths, and at least one of the luminescence center wavelengths is deviated by not less than 50 nm from a selected scattering center wavelength of the cholestric liquid crystal polymer sheet.

24. A liquid crystal display device according to claim 10, wherein the second polarizing film is a reflection-type polarizing film.

11. A liquid crystal display device comprising:

an STN liquid crystal cell with 180° and

270°

twisted nematic liquid crystals sandwiched between a pair of transparent substrates having respective transparent electrodes;

a retardation film disposed on a visible side of the STN liquid crystal cell;

a first polarizing film disposed on an outer side of the retardation film; and

a first retardation film for circularly polarized light, a cholestric liquid crystal polymer sheet, a second retardation film for circularly polarized light, a second polarizing film and a backlight disposed successively on a side of the STN liquid crystal cell, opposite from the visible side thereof,

wherein a face of said backlight, opposite to said second polarizing film, has a function of scattering polarized light.

12. A liquid crystal display device according to claim 11, wherein the retardation film is a twisted retardation film.