EP0229287A2
Expired / Lapsed
EP
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Optical change-over switch
Assignee: Hitachi Ltd
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Filing: 1986-12-01
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Granted: —
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Expires: 2006-12-01
Abstract
Abstract The liquid crystal cell (30) for the optical change-over switch comprises a pair of transparent substrates (l), a pair of transparent flat electrodes (2) provided on the respective opposing surfaces of the substrates, orientation control films (3) provided on the flat electrodes (2), two pair of comb shaped electrodes (33) respectively provided on the orientation control films (3), and a ferroelectric liquid crystal layer (4) confined between the substrates (l). The optical incidence plane (3l) to the cell (30) is so selected that the plane (3l) is away from the helical axes (9) of the ferroelectric liquid crystal in the cell (30) in the order of somewhat greater than the tilt angle ( ϑ t ) of the ferroelectric liquid crystal. The pair of flat electrodes (2) generate a first electric field (37a) perpendicular to the layer (32) and orient the long axes of the ferroelectric liquid crystal molecules into a first orientation (35a′) parallel to the layer (32) to induce a first refractive index which causes simultaneous reflection of unpolarized light beam (7 + 8) with a predetermined incidence angle ( ϑ ). The two pair of comb shaped electrodes (33) generate a second electric field (37b′) parallel to the layer and perpendicular to the helical axes (9) and orient the long axes of the molecules into a second orientation (35b′) not in parallel to the layer (32) to induce a second refractive index which causes simultaneous transmission of the unpolarized light beam (7 + 8) with the predetermined incidence angle ( ϑ ).
Inventors
- 👤 Yasuhiro Gunji
- 👤 Sadayuki Okada
- 👤 Masato Isogai
- 👤 Katsumi Kondo
- 👤 Masahiko Ibamoto
- 👤 Kazuhiro Hitachi Ibaraki Kogyo Kuwabara
- 👤 Atsushi Kanke
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 20:31
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/1326; G02F1/137; G02F1/139; G02F1/141
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
318 words
An optical change-over switch comprising, an input port (l2a, l2c, l3a, l3c 73a, 73c, 74a, 74c) and an output port (l2b, l2d, l3b, l3d, 73b, 73d, 74b, 74d) of a light beam having at least one of S and P polarization components (7, 8); a liquid crystal cell (l0, 30) for reflection and transmission of the light beam, said liquid crystal cell (l0, 30) including a pair of space-apart first and second transparent substrates (l) having respective opposed first and second parallel surfaces, a ferroelectric liquid crystal layer (4) confined between said first and second transparent substrates (l), and means for controlling orientation (2, 3, 33) of molecules (5) in the ferroelectric liquid crystal layer into a first molecule orientation (El, 37a, 37a′) inducing a first refractive index of the ferroelectric liquid crystal layer (4) to the respective polarization components of the incidence light beam so as to transmit at least one of S and P polarization components of the incidence light beam and into a second molecule orientation (E2, 37b, 37b′) inducing a second refractive index of the ferroelectric liquid crystal layer (4) to the respective polarization components of the incidence light beam so as to reflect at least one of S and P polarization components of the incidence light beam; and means for propagating (ll, l0l) the light beam from said input port (l2a, l2c, l3a, l3c, 73a, 73c, 74a, 74c) to said liquid crystal cell (l0, 30) and therefrom to said output port (l2b, l2d, l3b, l3d, 73b, 73d, 74b, 74d), the angle of the optical incidence plane (3l) defined by said light beam propagating means with respect to helical axes (9) of the ferroelectric liquid crystal in said liquid crystal cell (l0, 30) is so selected that the difference between the first and second refractive index ensures the change-over of at least one of S and P polarization components of the incidence light beam.
Claim 2
Dependent Claim
318 words
An optical change-over switch comprising, an input port (l2a, l2c, l3a, l3c 73a, 73c, 74a, 74c) and an output port (l2b, l2d, l3b, l3d, 73b, 73d, 74b, 74d) of a light beam having at least one of S and P polarization components (7, 8); a liquid crystal cell (l0, 30) for reflection and transmission of the light beam, said liquid crystal cell (l0, 30) including a pair of space-apart first and second transparent substrates (l) having respective opposed first and second parallel surfaces, a ferroelectric liquid crystal layer (4) confined between said first and second transparent substrates (l), and means for controlling orientation (2, 3, 33) of molecules (5) in the ferroelectric liquid crystal layer into a first molecule orientation (El, 37a, 37a′) inducing a first refractive index of the ferroelectric liquid crystal layer (4) to the respective polarization components of the incidence light beam so as to transmit at least one of S and P polarization components of the incidence light beam and into a second molecule orientation (E2, 37b, 37b′) inducing a second refractive index of the ferroelectric liquid crystal layer (4) to the respective polarization components of the incidence light beam so as to reflect at least one of S and P polarization components of the incidence light beam; and means for propagating (ll, l0l) the light beam from said input port (l2a, l2c, l3a, l3c, 73a, 73c, 74a, 74c) to said liquid crystal cell (l0, 30) and therefrom to said output port (l2b, l2d, l3b, l3d, 73b, 73d, 74b, 74d), the angle of the optical incidence plane (3l) defined by said light beam propagating means with respect to helical axes (9) of the ferroelectric liquid crystal in said liquid crystal cell (l0, 30) is so selected that the difference between the first and second refractive index ensures the change-over of at least one of S and P polarization components of the incidence light beam.
Claim 3
Dependent Claim
59 words
The optical change-over switch according to claim l, wherein the angle selected of the optical incidence plane (3l) with respect to the helical axes (9) of the ferroelectric liquid crystal is substantially the same as the tilt angle ( ϑ t ) of the long axes of molecules to the respective helical axes (9) of the ferroelectric liquid crystal.
Claim 4
Dependent Claim
60 words
The optical change-over switch according to claim 2, wherein said molecule orientation controlling means includes a first pair of transparent electrodes (2) generating a first electric field (El) having a first direction perpendicular to said ferroelectric liquid crystal layer (32) which causes the first molecule orientation in which long axes of the molecules are in parallel to said layer (32).
Claim 5
Dependent Claim
62 words
The optical change-over switch according to claim 3, wherein said first pair of transparent electrodes (2) further generate a second electric field (E2) having a second direction opposite to the first electric field (El) which causes the second molecule orientation substantially perpendicular to the first molecule orientation in which long axes of the molecules are still in parallel to said layer (32).
Claim 6
Dependent Claim
69 words
The optical change-over switch according to claim 3, wherein said molecule orientation controlling means further includes a second pair of transparent electrodes (33) generating a second electric field having a second direction parallel to said layer (32) and perpendicular to the helical axes (9) of the ferroelectric liquid crystal which causes the second molecule orientation in which long axes of molecules are not in parallel to said layer (32).
Claim 7
Dependent Claim
44 words
The optical change-over switch according to claim 5, wherein said first pair of electrodes are a pair of flat electrodes (l) provided respectively on the first surface of said first transparent substrate (l) and on the second surface of said second transparent substrate (l).
Claim 8
Dependent Claim
23 words
The optical change-over switch according to claim 6, wherein orientation control films (3) are respectively provided on said pair of flat electrodes (2).
Claim 9
Dependent Claim
33 words
The optical change-over switch according to claim 7, wherein said second pair of electrodes are a pair of comb shaped electrodes (33) provided on at least one of said orientation control films (3).
Claim 10
Dependent Claim
33 words
The optical change-over switch according to claim l, wherein the angle selected of the optical incidence plane (3l) with respect to the helical axes (9) of the ferroelectric liquid crystal is substantially zero.
Claim 11
Dependent Claim
182 words
l0. The optical change-over switch according to claim 9, wherein said molecule orientation controlling means includes a pair of flat transparent electrodes (2) provided respectively on the first surface of said first transparent substrate (l) and on the second surface of said second transparent substrate (l), orientation control films (3) respectively provided on said pair of flat transparent electrodes (2) and a pair of comb shaped transparent electrodes (33) provided on at least one of said orientation control films (3), said pair of transparent flat electrodes (2) generate a first electric field (37a) having a first direction perpendicular to said ferroelectric liquid crystal layer (32) which causes the first molecule orientation (35a) in which long axes of the molecules are in parallel to said layer (32), said pair of comb shaped transparent electrodes (33) generates a second electric field (37b) having a second direction parallel to said layer (32) and perpendicular to the helical axes (9) of the ferroelectric liquid crystal which causes the second molecule orientation (35b) in which long axes of molecules are not in parallel to said layer (32).
References Cited (Backward Citations)
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