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Patent US4995705A successfully refreshed from Google Patents.
US4995705A
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Device, method and apparatus for optical modulation using ferroelectric polymer liquid crystals
Assignee: Canon Inc
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Filing: 1987-12-16
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Granted: 1991-02-26
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Expires: 2007-12-16
Abstract
Abstract An optical modulation method comprises writing in a ferroelectric having a glass transition point at or above the glass transition point, and holding the resultant written state below the glass transition point. Preferably, the ferroelectric is formed in an optical modulation layer set to have an optical thickness capable of providing a multiple reflection state. The multiple reflection state of the optical modulation layer is locally changed at or above the glass transition point by irradiating the optical modulation layer under an electric field with a laser beam to write in the optical modulation layer.
Inventors
- 👤 Kazuo Yoshinaga
- 👤 Takeshi Miyazaki
- 👤 Toshikazu Ohnishi
- 👤 Yutaka Kurabayashi
- 👤 Yoshio Takasu
- 👤 Tadashi Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:13
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/004; G11B7/0055; G11B7/00557; C; C09; C09K; C09K19/00; C09K19/04; C09K19/38; C09K19/3833; C09K19/3842; C09K19/3852; C09K19/3857; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/133365; G02F1/137; G02F1/139; G02F1/141; G11B7/24; G11B7/241; G11B7/242; G11B7/244; G11B7/25; G11B9/00; G11B9/02
Claims Analysis
Total Claims: 59
Claim 1
Independent Claim
60 words
An optical modulation method, comprising: writing in a ferroelectric having a spontaneous polarization and a glass transition point by applying an electric field to the ferroelectric heated at or above the glass transition point to orient the spontaneous polarization of the ferroelectric to a prescribed direction, and holding the prescribed direction of the spontaneous polarization below the glass transition point.
Claim 2
Dependent Claim
60 words
An optical modulation method, comprising: writing in a ferroelectric having a spontaneous polarization and a glass transition point by applying an electric field to the ferroelectric heated at or above the glass transition point to orient the spontaneous polarization of the ferroelectric to a prescribed direction, and holding the prescribed direction of the spontaneous polarization below the glass transition point.
Claim 3
Dependent Claim
20 words
A method according to claim 1, wherein the written state is given by a change in birefringence of the ferroelectric.
Claim 4
Dependent Claim
22 words
A method according to claim 1, wherein said ferroelectric is heated at or above the glass transition point by a heat-generating electrode.
Claim 5
Dependent Claim
42 words
A method according to claim 1, wherein the ferroelectric is disposed between a pair of electrodes, and the ferroelectric is heated at or above the glass transition point by irradiation with a semiconductor laser beam through one of the pair of electrodes.
Claim 6
Dependent Claim
13 words
A method according to claim 1, wherein said ferroelectric is a ferroelectric polymer.
Claim 7
Dependent Claim
16 words
A method according to claim 5, wherein said ferroelectric polymer is a ferroelectric polymer liquid crystal.
Claim 8
Dependent Claim
77 words
An optical modulation method, comprising writing in a ferroelectric having a spontaneous polarization and a glass transition point by applying an electric field to the ferroelectric heated at or above the glass transition point to orient the spontaneous polarization of the ferroelectric to a prescribed direction, holding the prescribed direction of the spontaneous polarization below the glass transition point, and optically discriminating the prescribed direction of the spontaneous polarization as a difference in birefringence of the ferroelectric.
Claim 9
Dependent Claim
77 words
An optical modulation method, comprising writing in a ferroelectric having a spontaneous polarization and a glass transition point by applying an electric field to the ferroelectric heated at or above the glass transition point to orient the spontaneous polarization of the ferroelectric to a prescribed direction, holding the prescribed direction of the spontaneous polarization below the glass transition point, and optically discriminating the prescribed direction of the spontaneous polarization as a difference in birefringence of the ferroelectric.
Claim 10
Dependent Claim
18 words
A method according to claim 7, wherein the written state is discriminated by means of a beam splitter.
Claim 11
Dependent Claim
80 words
An optical modulation apparatus, comprising: an optical modulation device comprising a pair of electrodes and a ferroelectric having a spontaneous polarization and a glass transition point, said ferroelectric being disposed between the electrodes; and means for writing in the ferroelectric by heating the ferroelectric at or above the glass transition point under application of an electric field to orient the spontaneous polarization to a prescribed direction and holding the prescribed direction of the spontaneous polarization below the glass transition point.
Claim 12
Dependent Claim
80 words
An optical modulation apparatus, comprising: an optical modulation device comprising a pair of electrodes and a ferroelectric having a spontaneous polarization and a glass transition point, said ferroelectric being disposed between the electrodes; and means for writing in the ferroelectric by heating the ferroelectric at or above the glass transition point under application of an electric field to orient the spontaneous polarization to a prescribed direction and holding the prescribed direction of the spontaneous polarization below the glass transition point.
Claim 13
Dependent Claim
26 words
An apparatus according to claim 9, further comprising an alignment control layer in contact with the ferroelectric, said ferroelectric being in the form of a layer.
Claim 14
Dependent Claim
13 words
An apparatus according to claim 9, wherein said ferroelectric is a ferroelectric polymer.
Claim 15
Dependent Claim
16 words
An apparatus according to claim 9, wherein said ferroelectric polymer is a ferroelectric polymer liquid crystal.
Claim 16
Dependent Claim
25 words
An apparatus according to claim 9, wherein said writing means includes a heat-generating electrode for heating the ferroelectric at or above the glass transition point.
Claim 17
Dependent Claim
37 words
An apparatus according to claim 9, wherein said writing means includes a semiconductor laser beam for irradiating the ferroelectric through one of the pair of electrodes to heat the ferroelectric at or above the glass transition point.
Claim 18
Dependent Claim
106 words
An optical modulation apparatus, comprising: an optical modulation device comprising a pair of electrodes and a ferroelectric having a spontaneous polarization and a glass transition point, said ferroelectric being disposed between the electrodes; means for writing in the ferroelectric by heating the ferroelectric at or above the glass transition point under application of an electric field to orient the spontaneous polarization to a prescribed direction and holding the prescribed direction of the spontaneous polarization below the glass transition point; and means for optically discriminating the prescribed direction of the spontaneous polarization as a difference in the birefringence of the ferroelectric held below the glass transition point.
Claim 19
Dependent Claim
106 words
An optical modulation apparatus, comprising: an optical modulation device comprising a pair of electrodes and a ferroelectric having a spontaneous polarization and a glass transition point, said ferroelectric being disposed between the electrodes; means for writing in the ferroelectric by heating the ferroelectric at or above the glass transition point under application of an electric field to orient the spontaneous polarization to a prescribed direction and holding the prescribed direction of the spontaneous polarization below the glass transition point; and means for optically discriminating the prescribed direction of the spontaneous polarization as a difference in the birefringence of the ferroelectric held below the glass transition point.
Claim 20
Dependent Claim
26 words
An apparatus according to claim 15, further comprising an alignment control layer in contact with the ferroelectric, said ferroelectric being in the form of a layer.
Claim 21
Dependent Claim
13 words
An apparatus according to claim 15, wherein said ferroelectric is a ferroelectric polymer.
Claim 22
Dependent Claim
20 words
An apparatus according to claim 17, wherein said ferroelectric polymer is a polymer liquid crystal having a chiral smectic phase.
Claim 23
Dependent Claim
15 words
An apparatus according to claim 15, wherein said optical discrimination means includes a beam splitter.
Claim 24
Dependent Claim
87 words
An optical modulation apparatus, comprising: an optical modulation device including an optical modulation layer comprising an optical modulation compound having a birefringence, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; optical modulation means for changing the optical thickness of the optical modulation layer to change the multiple reflection state of the layer; and means for illuminating the optical modulation layer with readout light to optically discriminate the multiple reflection state as a difference in quantity of reflected light.
Claim 25
Dependent Claim
87 words
An optical modulation apparatus, comprising: an optical modulation device including an optical modulation layer comprising an optical modulation compound having a birefringence, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; optical modulation means for changing the optical thickness of the optical modulation layer to change the multiple reflection state of the layer; and means for illuminating the optical modulation layer with readout light to optically discriminate the multiple reflection state as a difference in quantity of reflected light.
Claim 26
Dependent Claim
34 words
An apparatus according to claim 20, wherein said optical modulation compound is capable of changing its birefringence in response to an electric field applied thereto and said optical modulation means comprises voltage application means.
Claim 27
Dependent Claim
16 words
An apparatus according to claim 20, wherein said optical modulation compound comprises a nematic liquid crystal.
Claim 28
Dependent Claim
17 words
An apparatus according to claim 20, wherein said optical modulation compound comprises a chiral smectic liquid crystal.
Claim 29
Dependent Claim
46 words
An apparatus according to claim 23, wherein said chiral smectic liquid crystal comprises a liquid crystal showing chiral smectic C phase, chiral smectic F phase, chiral smectic I phase, chiral smectic H phase, chiral smectic J phase, chiral smectic G phase or chiral smectic K phase.
Claim 30
Dependent Claim
22 words
An apparatus according to claim 20, wherein said optical modulation layer causes a change in optical thickness of 0.2 μm or less.
Claim 31
Dependent Claim
21 words
An optical modulation apparatus according to claim 20, further comprising an alignment control layer in contact with the optical modulation layer.
Claim 32
Dependent Claim
96 words
An optical modulation method, comprising: providing an optical modulation device including an optical modulation layer comprising an optical modulation compound having a birefringence and capable of changing the birefringence in response to an electric field applied thereto, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; changing the optical thickness of the optical modulation layer to change the multiple reflection state of the layer; and illuminating the optical modulation layer with readout light to optically discriminate the multiple reflection state as a difference in quantity of reflected light.
Claim 33
Dependent Claim
96 words
An optical modulation method, comprising: providing an optical modulation device including an optical modulation layer comprising an optical modulation compound having a birefringence and capable of changing the birefringence in response to an electric field applied thereto, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; changing the optical thickness of the optical modulation layer to change the multiple reflection state of the layer; and illuminating the optical modulation layer with readout light to optically discriminate the multiple reflection state as a difference in quantity of reflected light.
Claim 34
Dependent Claim
45 words
A method according to claim 27, wherein said optical modulation compound is capable of changing its birefringence in response to an electric field applied thereto and the optical thickness of the optical modulation layer is changed by applying a voltage across the optical modulation layer.
Claim 35
Dependent Claim
132 words
An optical modulation apparatus, comprising: an optical modulation device including an optical modulation layer comprising an optical modulation compound having a glass transition point and a refractive index anisotropy, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; recording means for writing in the optical modulation layer at or above the glass transition point of the optical modulation compound and holding the resultant written state below the glass transition point, said recording means including optical modulation means for changing the optical thickness of the optical modulation layer to change the multiple reflection state of the optical modulation layer; and means for illuminating the optical modulation layer with readout light to optically discriminate the multiple reflection state as a difference in quantity of reflected light.
Claim 36
Dependent Claim
132 words
An optical modulation apparatus, comprising: an optical modulation device including an optical modulation layer comprising an optical modulation compound having a glass transition point and a refractive index anisotropy, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; recording means for writing in the optical modulation layer at or above the glass transition point of the optical modulation compound and holding the resultant written state below the glass transition point, said recording means including optical modulation means for changing the optical thickness of the optical modulation layer to change the multiple reflection state of the optical modulation layer; and means for illuminating the optical modulation layer with readout light to optically discriminate the multiple reflection state as a difference in quantity of reflected light.
Claim 37
Dependent Claim
36 words
An apparatus according to claim 29, wherein said optical modulation compound is capable of changing its refractive index anisotropy in response to an electric field applied thereto, and said optical modulation means comprises voltage application means.
Claim 38
Dependent Claim
16 words
An apparatus according to claim 29, wherein said optical modulation compound comprises a polymer liquid crystal.
Claim 39
Dependent Claim
17 words
An apparatus according to claim 29, wherein said optical modulation compound comprises a ferroelectric polymer liquid crystal.
Claim 40
Dependent Claim
22 words
An apparatus according to claim 29, wherein said optical modulation layer causes a change in optical thickness of 0.2 μm or less.
Claim 41
Dependent Claim
21 words
An optical modulation apparatus according to claim 29, further comprising an alignment control layer in contact with the optical modulation layer.
Claim 42
Dependent Claim
131 words
An optical modulation method, comprising: providing an optical modulation device including an optical modulation layer comprising an optical modulation compound having a glass transition point and a refractive index anisotropy, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; a recording step for writing in the optical modulation layer at or above the glass transition point of the optical modulation compound and holding the resultant written state below the glass transition point, said recording step including a step for changing the optical thickness of the optical modulation layer to change the multiple reflection state of the optical modulation layer; and illuminating the optical modulation layer with readout light to optically discriminate the multiple reflection state as a difference in quantity of reflected light.
Claim 43
Dependent Claim
131 words
An optical modulation method, comprising: providing an optical modulation device including an optical modulation layer comprising an optical modulation compound having a glass transition point and a refractive index anisotropy, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; a recording step for writing in the optical modulation layer at or above the glass transition point of the optical modulation compound and holding the resultant written state below the glass transition point, said recording step including a step for changing the optical thickness of the optical modulation layer to change the multiple reflection state of the optical modulation layer; and illuminating the optical modulation layer with readout light to optically discriminate the multiple reflection state as a difference in quantity of reflected light.
Claim 44
Dependent Claim
45 words
A method according to claim 35, wherein said optical modulation compound is capable of changing its birefringence in response to an electric field applied thereto and the optical thickness of the optical modulation layer is changed by applying a voltage across the optical modulation layer.
Claim 45
Dependent Claim
160 words
An optical modulation apparatus, comprising: an optical modulation device including an optical modulation layer comprising an optical modulation compound which has a glass transition point and a refractive index anisotropy and is capable of changing its refractive index anisotropy in response to an electric field applied thereto, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; means for irradiating the optical modulation layer with writing light and applying an electric field of one polarity across the optical modulation layer to change the multiple reflection state of the optical modulation layer, thus writing in the optical modulation layer; and means for irradiating the optical modulation layer with erasure light having a plane of polarization different from that of the writing light and applying an electric field of the opposite polarity across the optical modulation layer to again change the multiple reflection state of the optical modulation layer, thus erasing the optical modulation layer.
Claim 46
Dependent Claim
160 words
An optical modulation apparatus, comprising: an optical modulation device including an optical modulation layer comprising an optical modulation compound which has a glass transition point and a refractive index anisotropy and is capable of changing its refractive index anisotropy in response to an electric field applied thereto, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; means for irradiating the optical modulation layer with writing light and applying an electric field of one polarity across the optical modulation layer to change the multiple reflection state of the optical modulation layer, thus writing in the optical modulation layer; and means for irradiating the optical modulation layer with erasure light having a plane of polarization different from that of the writing light and applying an electric field of the opposite polarity across the optical modulation layer to again change the multiple reflection state of the optical modulation layer, thus erasing the optical modulation layer.
Claim 47
Dependent Claim
16 words
An apparatus according to claim 37, wherein said optical modulation compound comprises a polymer liquid crystal.
Claim 48
Dependent Claim
17 words
An apparatus according to claim 27, wherein said optical modulation compound comprises a ferroelectric polymer liquid crystal.
Claim 49
Dependent Claim
21 words
An optical modulation apparatus according to claim 37, further comprising an alignment control layer in contact with the optical modulation layer.
Claim 50
Dependent Claim
157 words
An optical modulation apparatus, comprising: an optical modulation device including an optical modulation layer comprising an optical modulation compound which has a glass transition point and a refractive index anisotropy and is capable of changing its refractive index anisotropy in response to an electric field applied thereto, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; means for irradiating the optical modulation layer with writing light and applying an electric field of one polarity across the optical modulation layer to change the multiple-reflection state of the optical modulation layer, thus writing in the optical modulation layer; and means for irradiating the optical modulation layer with erasure light having a wavelength different from that of the writing light and applying an electric field of the opposite polarity across the optical modulation layer to again change the multiple reflection state of the optical modulation layer, thus erasing the optical modulation layer.
Claim 51
Dependent Claim
157 words
An optical modulation apparatus, comprising: an optical modulation device including an optical modulation layer comprising an optical modulation compound which has a glass transition point and a refractive index anisotropy and is capable of changing its refractive index anisotropy in response to an electric field applied thereto, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; means for irradiating the optical modulation layer with writing light and applying an electric field of one polarity across the optical modulation layer to change the multiple-reflection state of the optical modulation layer, thus writing in the optical modulation layer; and means for irradiating the optical modulation layer with erasure light having a wavelength different from that of the writing light and applying an electric field of the opposite polarity across the optical modulation layer to again change the multiple reflection state of the optical modulation layer, thus erasing the optical modulation layer.
Claim 52
Dependent Claim
16 words
An apparatus according to claim 41, wherein said optical modulation compound comprises a polymer liquid crystal.
Claim 53
Dependent Claim
17 words
An apparatus according to claim 41, wherein said optical modulation compound comprises a ferroelectric polymer liquid crystal.
Claim 54
Dependent Claim
21 words
An optical modulation apparatus according to claim 41, further comprising an alignment control layer in contact with the optical modulation layer.
Claim 55
Dependent Claim
163 words
An optical modulation apparatus, comprising: an optical modulation device including an optical modulation layer comprising an optical modulation compound which has a glass transition point and a refractive index anisotropy and is capable of changing its refractive index anisotropy in response to an electric field applied thereto, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; means for irradiating the optical modulation layer with writing light and applying an electric field of one polarity across the optical modulation layer to change the multiple reflection state of the optical modulation layer, thus writing in the optical modulation layer; and means for irradiating the optical modulation layer with erasure light having a wavelength and a plane of polarization different from those of the writing light and applying an electric field of the opposite polarity across the optical modulation layer to again change the multiple reflection state of the optical modulation layer, thus erasing the optical modulation layer.
Claim 56
Dependent Claim
163 words
An optical modulation apparatus, comprising: an optical modulation device including an optical modulation layer comprising an optical modulation compound which has a glass transition point and a refractive index anisotropy and is capable of changing its refractive index anisotropy in response to an electric field applied thereto, the optical modulation layer being set to an optical thickness capable of providing a multiple reflection state; means for irradiating the optical modulation layer with writing light and applying an electric field of one polarity across the optical modulation layer to change the multiple reflection state of the optical modulation layer, thus writing in the optical modulation layer; and means for irradiating the optical modulation layer with erasure light having a wavelength and a plane of polarization different from those of the writing light and applying an electric field of the opposite polarity across the optical modulation layer to again change the multiple reflection state of the optical modulation layer, thus erasing the optical modulation layer.
Claim 57
Dependent Claim
16 words
An apparatus according to claim 45, wherein said optical modulation compound comprises a polymer liquid crystal.
Claim 58
Dependent Claim
17 words
An apparatus according to claim 45, wherein said optical modulation compound comprises a ferroelectric polymer liquid crystal.
Claim 59
Dependent Claim
21 words
An optical modulation apparatus according to claim 45, further comprising an alignment control layer in contact with the optical modulation layer.
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