US5042924A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical phase plate and production process thereof
Assignee: Kureha Corp
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Filing: 1990-03-08
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Granted: 1991-08-27
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Expires: 2010-03-08
Abstract
Abstract An optical phase plate is provided in the form of a drawn and oriented film or sheet, having a composition comprising a vinylidene fluoride resin and a methyl methacrylate resin in a mixing ratio of the former to the latter between about 65/35 and about 85/15 by weight, in which the crystal structure of the vinylidene fluoride resin consists mainly of a β-form and the film or the sheet has dimensional stability and a retardation value R within a range from 500 to 650 nm. The optical phase plate is produced by uniformly kneading and melt-extruding the predetermined PVDF/PMMA mixture into a sheet and subjecting the sheet to drawing and then to heat treatment.
Inventors
- 👤 Shuji Terasaki
- 👤 Mitsuru Ohta
- 👤 Akiyasu Ishii
- 👤 Yuji Kojima
- 👤 Akira Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:00
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/30; C; C08; C08J; C08J5/00; C08J5/18; C08L; C08L27/00; C08L27/02; C08L27/12; C08L27/16; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/16; C08L33/00; C08L33/04; C08L33/06; C08L33/10; C08L33/12
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
84 words
An optical phase plate in the form of an oriented film or sheet having a composition comprising a vinylidene fluoride resin and a methyl methacrylate resin, wherein: a mixing ratio of the vinylidene fluoride resin to the methyl methacrylate resin is between about 65/35 and about 85/15 by weight, the crystal structure of the vinylidene fluoride resin mainly consists of a β-form and the film or the sheet has dimensional stability and a retardation value R within a range from 500 to 650 nm.
Claim 2
Dependent Claim
84 words
An optical phase plate in the form of an oriented film or sheet having a composition comprising a vinylidene fluoride resin and a methyl methacrylate resin, wherein: a mixing ratio of the vinylidene fluoride resin to the methyl methacrylate resin is between about 65/35 and about 85/15 by weight, the crystal structure of the vinylidene fluoride resin mainly consists of a β-form and the film or the sheet has dimensional stability and a retardation value R within a range from 500 to 650 nm.
Claim 3
Dependent Claim
29 words
An optical phase plate as claimed in claim 1, wherein: the volume fraction of a crystal form of said β-form in said vinylidene fluoride resin is more than 60%.
Claim 4
Dependent Claim
29 words
An optical phase plate as claimed in claim 1, wherein: the volume fraction of a crystal form of said β-form in said vinylidene fluoride resin is more than 70%.
Claim 5
Dependent Claim
29 words
An optical phase plate as claimed in claim 1, wherein: the volume fraction of a crystal form of said β-form in said vinylidene fluoride resin is more than 80%.
Claim 6
Dependent Claim
30 words
An optical phase plate as claimed in claim 1, wherein: said mixing ratio of the vinylidene fluoride resin to the methyl methacrylate resin is between about 70/30 and about 80/20.
Claim 7
Dependent Claim
117 words
A process for producing an optical phase plate, comprising the steps of: uniformly kneading a composition comprising a vinylidene fluoride resin and a methyl methacrylate resin in a mixing ratio of the former to the latter between about 65/35 and about 85/15 by weight; molding the kneaded composition into a film or sheet by melt extrusion followed by quenching, so that the crystal structure of the vinylidene fluoride resin in said film or sheet mainly consists of a β-form; drawing said film or sheet at a temperature from 25° C. to 150° C.; and applying heat treatment to the drawn film or sheet at a temperature in the range 50° C. to 160° C. after said drawing.
Claim 8
Dependent Claim
117 words
A process for producing an optical phase plate, comprising the steps of: uniformly kneading a composition comprising a vinylidene fluoride resin and a methyl methacrylate resin in a mixing ratio of the former to the latter between about 65/35 and about 85/15 by weight; molding the kneaded composition into a film or sheet by melt extrusion followed by quenching, so that the crystal structure of the vinylidene fluoride resin in said film or sheet mainly consists of a β-form; drawing said film or sheet at a temperature from 25° C. to 150° C.; and applying heat treatment to the drawn film or sheet at a temperature in the range 50° C. to 160° C. after said drawing.
Claim 9
Dependent Claim
33 words
A process for producing an optical phase plate as claimed in claim 6, wherein: the volume fraction of a crystal form of said β-form in said vinylidene fluoride resin is more than 60%.
Claim 10
Dependent Claim
33 words
A process for producing an optical phase plate as claimed in claim 6, wherein: the volume fraction of a crystal form of said β-form in said vinylidene fluoride resin is more than 70%.
Claim 11
Dependent Claim
34 words
A process for producing an optical phase plate as claimed in claim 6, wherein: said mixing ratio of the vinylidene fluoride resin to the methyl methacrylate resin is between about 70/30 and about 80/20.
Claim 12
Dependent Claim
34 words
A process for producing an optical phase plate as claimed in claim 6, wherein: said drawing is done on the film or sheet while the vinylidene fluoride resin therein is in an unmolten state.
Claim 13
Dependent Claim
87 words
In an optical control device, a phase compensation means comprising: an optical phase plate comprising an oriented film or sheet having a composition comprising a vinylidene fluoride resin and a methyl methacrylate resin, in a mixing ratio of the former to the latter between about 65/35 and about 85/15 by weight, wherein a crystal structure of the vinylidene fluoride resin mainly consists of a β-form thereof and the film or sheet has dimensional stability and a retardation value R within a range from 500 to 650 nm.
Claim 14
Dependent Claim
87 words
In an optical control device, a phase compensation means comprising: an optical phase plate comprising an oriented film or sheet having a composition comprising a vinylidene fluoride resin and a methyl methacrylate resin, in a mixing ratio of the former to the latter between about 65/35 and about 85/15 by weight, wherein a crystal structure of the vinylidene fluoride resin mainly consists of a β-form thereof and the film or sheet has dimensional stability and a retardation value R within a range from 500 to 650 nm.
Claim 15
Dependent Claim
28 words
An optical control device according to claim 11, wherein: the volume fraction of a crystal form of said β-form in said vinylidene fluoride resin is more than 60%.
Claim 16
Dependent Claim
28 words
An optical control device according to claim 11, wherein: the volume fraction of a crystal form of said β-form in said vinylidene fluoride resin is more than 70%.
Claim 17
Dependent Claim
28 words
An optical control device according to claim 11, wherein: the volume fraction of a crystal form of said β-form in said vinylidene fluoride resin is more than 80%.
Claim 18
Dependent Claim
29 words
An optical control device according to claim 11, wherein: said mixing ratio of the vinylidene fluoride resin to the methyl methacrylate resin is between about 70/30 and about 80/20.
Claim 19
Dependent Claim
135 words
An optical phase plate, usable as a λ-plate in an optical control device to prevent coloration of a display screen in a black and white liquid crystal display unit, comprising: an oriented film or sheet having a composition comprising a vinylidene fluoride resin and a methyl methacrylate resin in a mixing ratio of the former to the latter between about 65/35 and about 85/15 by weight, wherein the crystal structure of the vinylidene fluoride resin consists mainly of a β-form thereof and the film or sheet has dimensional stability with a final shrinkage of 3% or less and a retardation value R within a range from 500 to 650 nm, whereby a transmittance of at least 90% with a haze value of 0.3% or less is provided by the optical phase plate to incident light.
Claim 20
Dependent Claim
135 words
An optical phase plate, usable as a λ-plate in an optical control device to prevent coloration of a display screen in a black and white liquid crystal display unit, comprising: an oriented film or sheet having a composition comprising a vinylidene fluoride resin and a methyl methacrylate resin in a mixing ratio of the former to the latter between about 65/35 and about 85/15 by weight, wherein the crystal structure of the vinylidene fluoride resin consists mainly of a β-form thereof and the film or sheet has dimensional stability with a final shrinkage of 3% or less and a retardation value R within a range from 500 to 650 nm, whereby a transmittance of at least 90% with a haze value of 0.3% or less is provided by the optical phase plate to incident light.
Claim 21
Dependent Claim
28 words
An optical phase plate according to claim 16, wherein: the volume fraction of a crystal form of said β-form in said vinylidene fluoride resin is more than 60%.
Claim 22
Dependent Claim
28 words
An optical phase plate according to claim 16, wherein: the volume fraction of a crystal form of said β-form in said vinylidene fluoride resin is more than 70%.
Claim 23
Dependent Claim
28 words
An optical phase plate according to claim 18, wherein: the volume fraction of a crystal form of said β-form in said vinylidene fluoride resin is more than 80%.
Claim 24
Dependent Claim
29 words
An optical phase plate according to claim 18, wherein: said mixing ratio of the vinylidene fluoride resin to the methyl methacrylate resin is between about 70/30 and about 80/20.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-08-26 | 1995-02-25 | 1995-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-26 | 1999-02-25 | 1999-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-26 | 2003-02-25 | 2003-08-27 | $7700.00 | Window Closed / Lapsed |