Aligning method of liquid crystal, production process of liquid crystal device, and liquid crystal device

• US 5,798,056 A
• Filed: 01/31/1996
• Issued: 08/25/1998
• Est. Priority Date: 02/01/1995
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Nakamura, Katsutoshi
• Primary Examiner(s): WU, SHEAN CHIU
• Application Number:
  US08/594,796
• Time in Patent Office: 937 Days
• Field of Search: 252/299.01, 349/86, 349/89, 349/123, 349/133, 428/1
• US Class Current: 252/299.01
• CPC Class Codes: C09K 19/0266 Antiferroelectrics
• CPC Class Codes: C09K 2323/02 Alignment layer characterised by chemical composition
• CPC Class Codes: G02F 1/133784 by rubbing
• CPC Class Codes: G02F 1/141 using ferroelectric liquid crystals

Abstract

An aligning method of a chiral smectic liquid crystal showing a phase transition series of isotropic phase, smectic phase, and chiral smectic phase in this order on temperature decrease is provided. In the aligning method, the chiral smectic liquid crystal is disposed between a pair of electrode plates at least one of which is provided with an alignment control layer, preferably one having been subjected to a uniaxial aligning treatment (e.g., rubbing), and then is subjected to a treatment including a cycle of heating and cooling in temperatures ranging between a lower limit temperature showing chiral smectic phase and an upper limit temperature showing isotropic phase and smectic phase in mixture. The upper limit temperature may preferably be below an isotropic-smectic phase transition temperature by at most 3° C., particularly at most 1° C. The aligning method is effective in improving an alignment characteristic of liquid crystal molecules to provide a uniform alignment state free from an aligning defect.

Claims

1. An aligning method of a chiral smectic liquid crystal, comprising:

disposing a chiral smectic liquid crystal between a pair of electrode plates at least one of which is provided with an alignment control layer, said chiral smectic liquid crystal showing a phase transition series of isotropic phase, smectic A phase and chiral smectic phase in this order on temperature decrease; and

subjecting said chiral smectic liquid crystal to a treatment including a cycle of the steps of heating up to a first temperature at which said liquid crystal shows isotropic phase and smectic A phase in mixture and cooling down to a second temperature at which said liquid crystal shows chiral smectic phase.

2. A method according to claim 1, wherein said first temperature ranges from at most 3°

C. below an isotropic-smectic A phase transition initiation temperature to the phase transition initiation temperature.

3. A method according to claim 1, wherein said first temperature ranges from at most 1°

C. below an isotropic-smectic A phase transition initiation temperature to the phase transition initiation temperature.

4. A method according to claim 1, wherein said pair of electrode plates are each provided with an alignment control layer, either one or both of the alignment control layers having been subjected to a uniaxial aligning treatment.

5. A method according to claim 1, wherein said pair of electrode plates at least one of which is provided with an alignment control layer includes one electrode plate provided with an alignment control layer having been subjected to a uniaxial aligning treatment.

6. A method according to claim 4, wherein said uniaxial aligning treatment comprises rubbing.

7. A method according to claim 5, wherein said uniaxial aligning treatment comprises rubbing.

8. A method according to claim 1, wherein said chiral smectic liquid crystal comprises at least one species of a compound selected from compounds represented by the formula (I-1) and (I-2) shown below:

Formula (I-1) ##STR6## a, b and c independently denote an integer of 0-3 with the proviso that a+b+c is at least 2;

M₁ and N₁ independently denote --COO--, --OCO--, --COS--, --SCO--, --COSe--, --SeCO--, --COTe--, --TeCO--, --CH₂ CH₂ --, --CH═

CH--, --C.tbd.C--,--CH═

N--, --N═

CH--, --CH₂ O--, --OCH₂ --, --CO--, --O-- or a single bond;

X, Y and Z independently denote --H, --Cl, --F, --Br, --I, --OH, --OCH₃, --CN or --NO₂ and l, m and n independently denote an integer of 0-4;

G₁ is --COO--C_e H_2e --, --O--C_e H_2e --, --C_e H_2e --, --OSOO--, --OOSO--, --SOO--, --SOOC_e H_2e --, --OC_e H_2e --OC_e'"'"' H_2e'"'"' --, --C_e H_2e --N(C_p H_2p+1)--SO₂ --, --C_e H_2e --N(C_p H_2p+1)--CO--wherein e and e'"'"' independently denote an integer of 1-20, and p is an integer of 1-4;

A₁ is a linear or branched group represented by --O--C_f H_2f --O--C_g H_2g+1, --C_f H_2f --O--C_g H_2g+1, --C_f H_2f --R'"'"', --O--C_f H_2f --R'"'"', --COO--C_f H_2f --R'"'"', --OCO--C_f H_2f --R'"'"' wherein R'"'"' is --Cl, --F, --CF₃, --NO₂, --CN, --H, --COO--C_f'"'"' H_2f'"'"'+1 or --OCO--C_f'"'"' H_2f'"'"'+1 in which f, f'"'"' and g independently denote an integer of 1-20; and

R₁ is --C_w F_2w+1 wherein w is an integer of 1-20; and

Formula (I-2) ##STR7## a, b and c independently denote an integer of 0-3 with the proviso that a+b+c is at least 2;

M₂ and N₂ independently denote --COO--, --OCO--, --COS--, --SCO--, --COSe--, --SeCO--, --COTe--, --TeCO--, .paren open-st.CH₂ CH₂ .paren close-st._d wherein d is an integer of 1-4, --CH═

CH--, --C.tbd.C--, --CH═

N--, --N═

CH--, --CH₂ O--, --OCH₂ --, --CO--, --O--or a single bond;

X'"'"', Y'"'"' and Z'"'"' independently denote --H, --Cl, --F, --Br, --I, --OH, --OCH₃, --CH₃, --CF₃, --OCF₃ --, --CN or --NO₂ and l, m and n independently denote an integer of 0-4;

G₂ is --COO--C_e H_2e --, --O--C_e H_2e --, --O.paren open-st.C_e" H_2e" O.paren close-st._t C_e '"'"'H_2e'"'"' --, --C_e H_2e --, --OSOO--, --SOO--, --SOOC_e H_2e --, --C_e H_2e --N(C_p H_2p+1)--SO₂ -- or --C_e H_2e --N(C_p H_2p+1)--CO-- wherein e and e'"'"' independently denote an integer of 1-20, e" is an integer of 1-10 for each C_e" H_2e" O group, t is an integer of 1-6 and p is an integer of 0-4;

A₂ is a linear or branched group represented by --O.paren open-st.C_f H_2f O.paren close-st._u --C_h H_2h+1, .paren open-st.C_f H_2f O .paren close-st._u C_h H_2h+1, --C_f H_2f --W, --O--C_f H_2f --W, --COO--C_f H_2f --W, or --OCO--C_f H_2f --W wherein W is --Cl, --F, --CF₃, --NO₂, --CN, --H, --COO--C_h H_2h+1 or --OCO--C_h H_2h+1 in which f and h independently denote an integer of 1-20 and u is an integer of 1-10; and

R₂ is .paren open-st.C_x'"'"' F_2x'"'"' O.paren close-st._z'"'"' C_y'"'"' F_2y'"'"'+1 wherein x'"'"' is an integer of 1-10 for each C_x'"'"' F_2x'"'"' O group, y'"'"' is an integer of 1-10, and z'"'"' is an integer of 1-10.

9. A process for producing a liquid crystal device, comprising:

providing a cell structure comprising a pair of oppositely disposed electrode plates at least one of which is provided with an alignment control layer and a chiral smectic liquid crystal disposed between the electrode plates;

heating and injecting said chiral smectic liquid crystal into the cell structure; and

subjecting said chiral smectic liquid crystal to a treatment including a cycle of the steps of heating up to a first temperature at which said liquid crystal shows isotropic phase and smectic A phase in mixture and cooling down to a second temperature at which said liquid crystal shows chiral smectic phase.

10. A process according to claim 9, wherein said chiral smectic liquid crystal is heated to a temperature at which said liquid crystal shows isotropic phase and is injected into the cell structure at the temperature.

11. A process according to claim 9, wherein said first temperature ranges from at most 3°

C. below an isotropic-smectic A phase transition initiation temperature to the phase transition initiation temperature.

12. A process according to claim 9, wherein said first temperature ranges from at most 1°

C. below an isotropic-smectic A phase transition initiation temperature to the phase transition initiation temperature.

13. A process according to claim 9, wherein said pair of electrode plates are each provided with an alignment control layer, either one or both of the alignment control layers having been subjected to a uniaxial aligning treatment.

14. A process according to claim 9, wherein said pair of electrode plates at least one of which is provided with an alignment control layer includes one electrode plate provided with an alignment control layer having been subjected to a uniaxial aligning treatment.

15. A process according to claim 13, wherein said uniaxial aligning treatment comprises rubbing.

16. A process according to claim 14, wherein said uniaxial aligning treatment comprises rubbing.

17. A process according to claim 9, wherein said chiral smectic liquid crystal comprises at least one species of a compound selected from compounds represented by the formula (I-1) and (I-2) shown below:

Formula (I-1) ##STR8## a, b and c independently denote an integer of 0-3 with the proviso that a+b+c is at least 2;

M₁ and N₁ independently denote --COO--, --OCO--, --COS--, --SCO--, --COSe--, --SeCO--, --COTe--, --TeCO--, --CH₂ CH₂ --, --CH═

CH--, --C.tbd.C--, --CH═

N--, --N═

CH--, --CH₂ O--, --OCH₂ --, --CO--, --O-- or a single bond;

X, Y and Z independently denote --H, --Cl, --F, --Br, --I, --OH, --OCH₃, --CN or --NO₂ and l, m and n independently denote an integer of 0-4;

G₁ is --COO--C_e H_2e --, --O--C_e H_2e --, --C_e H_2e --, --OSOO--, --OOSO--, --SOO--, --SOOC_e H_2e --, --OC_e H_2e --OC_e'"'"' H_2e'"'"' --, --C_e H_2e --N(C_p H_2p+1)--SO₂ --, --C_e H_2e --N(C_p H_2p+1)--CO-- wherein e and e'"'"' independently denote an integer of 1-20, and p is an integer of 1-4;

A₁ is a linear or branched group represented by --O--C_f H_2f --O--C_g H_2g+1, --C_f H_2f --O--C_g H_2g+1, --C_f H_2f --R'"'"', --O--C_f H_2f --R'"'"', --COO--C_f H_2f --R'"'"', --OCO--C_f H_2f --R'"'"' wherein R'"'"' is --Cl, --F, --CF₃, --NO₂, --CN, --H, --COO--C_f'"'"' H_2f'"'"'+l or --OCO--C_f'"'"' H_2f'"'"'+1 in which f, f'"'"' and g independently denote an integer of 1-20; and

R₁ is --C_w F_2w+1 wherein w is an integer of 1-20; and

Formula (I-2) ##STR9## a, b and c independently denote an integer of 0-3 with the proviso that a+b+c is at least 2;

M₂ and N₂ independently denote --COO--, --OCO--, --COS--, --SCO--, --COSe--, --SeCO--, --COTe--, --TeCO--, .paren open-st.CH₂ CH₂)_d wherein d is an integer of 1-4, --CH═

CH--, --C.tbd.C--, --CH═

N--, --N═

CH--, --CH₂ O--, --OCH₂ --, --CO--, --O-- or a single bond;

X'"'"', Y'"'"' and Z'"'"' independently denote --H, --Cl, --F, --Br, --I, --OH, --OCH₃, --CH₃, --CF₃, --OCF₃ --, --CN or --NO₂ and l, m and n independently denote an integer of 0-4;

G₂ is --COO--C_e H_2e --, --O--C_e H_2e --, --O(C_e" H_2e" O)_t C_e'"'"' H_2e'"'"' --, --C_e H_2e --, --OSOO--, --SOO--, --SOOC_e H_2e --, --C_e H_2e --N(C_p H_2p+1)--SO₂ -- or --C_e H_2e --N(C_p H_2p+1)--CO--wherein e and e'"'"' independently denote an integer of 1-20, e" is an integer of 1-10 for each C_e" H_2e" O group, t is an integer of 1-6 and p is an integer of 0-4;

A₂ is a linear or branched group represented by --O.paren open-st.C_f H_2f O.paren close-st._u --C_h H_2h+1, .paren open-st.C_f H_2f O.paren close-st._u C_h H_2h+1, --C_f H_2f --W, --O--C_f H_2f --W, --COO--C_f H_2f --W, or --OCO--C_f H_2f --W wherein W is --Cl, --F, --CF₃, --NO₂, --CN, --H, --COO--C_h H_2h+1 or --OCO--C_h H_2h+1 in which f and h independently denote an integer of 1-20 and u is an integer of 1-10; and

R₂ is .paren open-st.C_x'"'"' F_2x'"'"' O.paren close-st._z'"'"' F_2y'"'"'+1 wherein x'"'"' is an integer of 1-10 for each C_x'"'"' F_2x'"'"' O group, y'"'"' is an integer of 1-10, and z'"'"' is an integer of 1-10.

18. A liquid crystal device, comprising:

a pair of electrode plates at least one of which is provided with an alignment control layer and a chiral smectic liquid crystal disposed between the electrode plates, wherein

said chiral smectic liquid crystal is subjected to a treatment including a cycle of the steps of heating up to a first temperature at which said liquid crystal shows isotropic phase and smectic A phase in mixture and cooling down to a second temperature at which said liquid crystal shows chiral smectic phase.

19. A device according to claim 18, wherein said pair of electrode plates are each provided with an alignment control layer, either one or both of the alignment control layers having been subjected to a uniaxial aligning treatment.

20. A device according to claim 18, wherein said pair of electrode plates at least one of which is provided with an alignment control layer includes one electrode plate provided with an alignment control layers having been subjected to a uniaxial aligning treatment.

21. A device according to claim 19, wherein said uniaxial aligning treatment comprises rubbing.

22. A device according to claim 20, wherein said uniaxial aligning treatment comprises rubbing.