Two layer liquid crystal display apparatus

• US 6,833,885 B2
• Filed: 03/25/2002
• Issued: 12/21/2004
• Est. Priority Date: 03/28/2001
• Status: Expired due to Fees

• Current Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Original Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Inventors: Hisamitsu, Akihito, Kobayashi, Nobuyuki, Ueda, Noboru, Ueda, Hideaki
• Primary Examiner(s): Chowdhury, Tarifur R.
• Assistant Examiner(s): Akkapeddi, Prasad R
• Application Number:
  US10/105,182
• Publication Number:
  US 20020176041A1
• Time in Patent Office: 1,002 Days
• Field of Search: 349/74, 349/115, 349/185, 349/186, 349/78, 349/184
• US Class Current: 349/74
• CPC Class Codes: G02F 1/13471 in which all the liquid crystal cells or layers remain transparent, e.g. FLC, ECB, DAP, HAN, TN, STN, SBE-LC cells G02F1/13475 takes precedence
• CPC Class Codes: G02F 1/13718 based on a change of the texture state of a cholesteric liquid crystal

Abstract

A liquid crystal display apparatus includes a first liquid crystal layer having first liquid crystal exhibiting a cholesteric phase at a room temperature, and being tuned to selectively reflect light of a wavelength λ1 within a visible wavelength range; and a second liquid crystal layer disposed on the first liquid crystal layer, having second liquid crystal exhibiting a cholesteric phase at the room temperature, and being tuned to selectively reflect light of a wavelength λ2 within the visible wavelength range, wherein a difference between the selective reflection wavelengths λ1 and λ2 is in a range from 100 nm to 150 nm.

Claims

1. A liquid crystal display apparatus having a front surface and a rear surface, the liquid crystal display apparatus comprising:

first and second substrates;

an intermediate transparent substrate;

a first liquid crystal layer disposed adjacent to said front surface, including first liquid crystal exhibiting a cholesteric phase at a room temperature, and being tuned to selectively reflect light of a wavelength λ

1 within a visible wavelength range; and

a second liquid crystal layer disposed adjacent to said rear surface, including second liquid crystal exhibiting a cholesteric phase at the room temperature, and being tuned to selectively reflect light of a wavelength λ

2 within the visible wavelength range,

wherein a difference between said selective reflection wavelengths λ

1 and λ

2 is in a range from 100 nm to 150 nm, and said first liquid crystal layer is disposed between said first substrate and said intermediate substrate, said second liquid crystal layer is disposed between said intermediate substrate and said second substrate, and at least one of said first and second substrates is transparent and is provided with a transparent electrode, and the other of said first and second substrates is provided with an electrode.

2. The liquid crystal display apparatus according to claim 1, wherein

said intermediate transparent substrate is an intermediate transparent substrate provided on its opposite surfaces with transparent electrodes, respectively.

3. The liquid crystal display apparatus according to claim 1, wherein

said intermediate transparent substrate is an intermediate transparent substrate formed of layered transparent substrate portions, each being provided on one of its surfaces with a transparent electrode, and having the other surface attached to the other substrate portion.

4. The liquid crystal display apparatus according to claim 1, wherein

said intermediate transparent substrate is an intermediate transparent substrate not provided with an electrode.

5. The liquid crystal display apparatus according to claim 1, wherein

at least one of said first and second substrates is a resin substrate.

6. The liquid crystal display apparatus according to claim 1, wherein

said intermediate transparent substrate is a resin substrate.

7. The liquid crystal display apparatus according to claim 1, wherein

at least one of said first and second substrates has an orientation stabilizing film in contact with one of the liquid crystal layers, and at least one surface of said intermediate substrate has an orientation stabilizing film in contact with one of the liquid crystal layers.

8. The liquid crystal display apparatus according to claim 1, wherein

said transparent intermediate substrate comprises a pair of transparent substrates joined together.

9. The liquid crystal display apparatus according to claim 8, further comprising:

transparent electrodes disposed on the unjoined sides of said pair of transparent substrates.

10. A liquid crystal display apparatus comprising:

a first substrate disposed adjacent to a viewing surface of said liquid crystal display apparatus;

a first liquid crystal material disposed adjacent to said first substrate, said first liquid crystal material having a peak reflectance at a first wavelength;

a second substrate disposed adjacent to a rear surface of said liquid crystal display apparatus;

a second liquid crystal material disposed adjacent to said second substrate, said second liquid crystal material having a peak reflectance at a second wavelength; and

a third substrate disposed between the first and second liquid crystal materials,

wherein each of said first and second liquid crystal materials have a refractive index anisotropy of not less than about 0.15, and

wherein a difference between said first and second wavelengths is not less than about 100 nm and not more than about 150 nm.

11. The liquid crystal display apparatus according to claim 10, further comprising:

a first electrode disposed on the first substrate; and

a second electrode disposed on the second substrate so that, the first and second liquid crystal materials are between said first and second electrodes.

12. The liquid crystal display apparatus according to claim 11, further comprising:

driver circuitry coupled to the first and second electrodes, the driver circuitry providing a voltage across the first and second liquid crystal materials.

13. The liquid crystal display apparatus according to claim 10, further comprising:

a first pair of electrodes disposed on said first and third substrates so that the first liquid crystal material is between the first pair of electrodes; and

a second pair of electrodes disposed on said second and third substrates so that said second liquid crystal material is between the second pair of electrodes.

14. The liquid crystal display apparatus according to claim 13, further comprising:

driver circuitry coupled to the first and second pairs of electrodes, the driver circuitry selectively providing first and second predetermined voltages across the first and second liquid crystal materials, respectively.

15. The liquid crystal display apparatus according to claim 14, wherein:

said driver circuitry is coupled to said first and second pairs of electrodes so that said first and second pairs of electrodes are electrically parallel.

16. The liquid crystal display apparatus according to claim 14, wherein:

said first and second predetermined voltages are selected so that a ratio between the magnitudes of the peak reflectance of the first and second liquid crystal materials has a predetermined value.

17. The liquid crystal display apparatus according to claim 16, wherein said ratio has a value of about 1.

18. A liquid crystal display apparatus comprising:

a front substrate;

a rear substrate;

a separator disposed between said front and rear substrates;

two liquid crystals, including a first liquid crystal disposed between said front substrate and said separator, and a second liquid crystal disposed between said separator and said rear substrate, wherein

both of the liquid crystals exhibit a cholesteric phase at room temperature,

both of the liquid crystals have a refractive index anisotropy (Δ

n) not less than about 0.15; and

the peak reflectance wavelengths of the first and second liquid crystals are separated by between 100 nm and 150 nm.

19. A liquid crystal display apparatus having a front surface and a rear surface, the liquid crystal display apparatus comprising:

first and second substrates;

an intermediate substrate;

a first liquid crystal layer disposed adjacent to said front surface, including first liquid crystal exhibiting a cholesteric phase at a room temperature, and being tuned to selectively reflect light of a wavelength λ

1 within a visible wavelength range; and

a second liquid crystal layer disposed adjacent to said rear surface, including second liquid crystal exhibiting a cholesteric phase at the room temperature, and being tuned to selectively reflect light of a wavelength λ

2 within the visible wavelength range,

wherein;

a difference between said selective reflection wavelengths λ

1 and λ

2 is in a range from 100 nm to 150 nm,

said first liquid crystal layer is disposed between said first substrate and said intermediate substrate, and said second liquid crystal layer is disposed between said intermediate substrate and said second substrate, and

at least one of said first and second substrates is transparent and is provided with a transparent electrode, and the other of said first and second substrates is provided with an electrode.

20. A liquid crystal display apparatus having a front surface and a rear surface, the liquid crystal display apparatus comprising:

a first liquid crystal material disposed adjacent to said front surface, exhibiting a cholesteric phase at a room temperature, and being tuned to selectively reflect light of a wavelength λ

1 within a visible wavelength range;

a second liquid crystal material disposed adjacent to said rear surface, exhibiting a cholesteric phase at a room temperature, and being tuned to selectively reflect light of a wavelength λ

2 within a visible wavelength range;

first and second substrates; and

an intermediate layer;

wherein

a difference between said selective reflection wavelength λ

1 and λ

2 is in a range from 100 nm and 150 nm, and

said first liquid crystal material is disposed between said first substrate and said intermediate layer, said second liquid crystal material is disposed between said intermediate layer and said second substrate, and at least one of said first and second substrates is transparent and is provided with a transparent electrode, and the other of said first and second substrates is provided with an electrode.