US5157529A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Display device having wavelength-dependent birefringence compensation
Assignee: US Philips Corp
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Filing: 1991-04-18
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Granted: 1992-10-20
•
Expires: 2011-04-18
Abstract
Abstract By a suitable choice of a retardation foil with a specific value of Δn (λ) it is possible to make the transmission/voltage characteristic curves for, for example, red, green and blue light extend parallel in an ECB display. The same type of display can then be used for modulating three colors, with modulation voltages shifted for each color.
Inventors
- 👤 Henricus G. Koopman
- 👤 Hendrik A. Van Sprang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:30
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G02F1/1393; G02F1/133; G02F1/1333; G02F1/1335; G02F1/13363; H; H04; H04N; H04N9/00; H04N9/12; H04N9/31; H04N9/3102; H04N9/312; G02F1/133637
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
184 words
A display device provided with a layer of liquid crystalline material having a positive dielectric anisotropy between a first transparent supporting plate provided with at least a first transparent drive electrode and a second supporting plate provided with at least a second drive electrode, the layer of liquid crystalline material being switchable via electric voltages on the drive electrodes between a first state, in which the molecules of the liquid crystalline material have a first direction of orientation substantially parallel to the supporting plates or extend at a small angle to a plane parallel to the supporting plates, and a second state, in which the molecules of the liquid crystalline material have a second direction of orientation substantially perpendicular to the plane of the supporting plates, the device being further provided with an extra layer of birefringent material compensating a given quantity of birefringence in the layer of liquid crystalline material, the phase shift δ of incident polarised light due to birefringence in the extra layer of birefringent material decreasing as a function of the increasing wavelength, characterized in that 20°<δr<40°, 25°<δg<40° and 30°<δb<50°.
Claim 2
Dependent Claim
184 words
A display device provided with a layer of liquid crystalline material having a positive dielectric anisotropy between a first transparent supporting plate provided with at least a first transparent drive electrode and a second supporting plate provided with at least a second drive electrode, the layer of liquid crystalline material being switchable via electric voltages on the drive electrodes between a first state, in which the molecules of the liquid crystalline material have a first direction of orientation substantially parallel to the supporting plates or extend at a small angle to a plane parallel to the supporting plates, and a second state, in which the molecules of the liquid crystalline material have a second direction of orientation substantially perpendicular to the plane of the supporting plates, the device being further provided with an extra layer of birefringent material compensating a given quantity of birefringence in the layer of liquid crystalline material, the phase shift δ of incident polarised light due to birefringence in the extra layer of birefringent material decreasing as a function of the increasing wavelength, characterized in that 20°<δr<40°, 25°<δg<40° and 30°<δb<50°.
Claim 3
Dependent Claim
46 words
A display device as claimed in claim 1, characterized in that it holds for the values δr, δg, δb of the phase shift due to the birefringence of the extra layer at wavelengths in the red (λr), green (λg) and blue (λb) that: δg/δr>λr/λg and δb/δg>λg/λb.
Claim 4
Dependent Claim
17 words
A display device as claimed in claim 2, characterized in that it holds that: δg/δr>658/546 and δb/δg>546/480.
Claim 5
Dependent Claim
39 words
A display device as claimed in claim 3, characterized in that the transmission/voltage characteristic curves for red, green and blue or at least two other composite colours extend substantially parallel through at least a part of the voltage range.
Claim 6
Dependent Claim
23 words
A display device as claimed in claim 3, characterized in that the extra layer of birefringent material comprises polymethyl methacrylate and polyvinylidene fluoride.
Claim 7
Dependent Claim
23 words
A display device as claimed in claim 3, characterized in that the second supporting plate is provided with a layer of reflecting material.
Claim 8
Dependent Claim
48 words
A display device as claimed in claim 3, characterized in that the device comprises a polariser and an analyser, the angle between the direction of polarisation of the polariser and the direction of orientation of the molecules at the area of the first supporting plate being substantially 45°.
Claim 9
Dependent Claim
52 words
A display device as claimed in claim 3, characterized in that it comprises at least a light source whose light is incident on the liquid crystalline material and is reflected dependent on the optical state of the liquid crystalline material, and in that the light thus reflected is imaged via projection means.
Claim 10
Dependent Claim
39 words
A display device as claimed in claim 2, characterized in that the transmission/voltage characteristic curves for red, green and blue or at least two other composite colours extend substantially parallel through at least a part of the voltage range.
Claim 11
Dependent Claim
23 words
A display device as claimed in claim 2, characterized in that the extra layer of birefringent material comprises polymethyl methacrylate and polyvinylidene fluoride.
Claim 12
Dependent Claim
23 words
A display device as claimed in claim 2, characterized in that the second supporting plate is provided with a layer of reflecting material.
Claim 13
Dependent Claim
48 words
A display device as claimed in claim 2, characterized in that the device comprises a polariser and an analyser, the angle between the direction of polarisation of the polariser and the direction of orientation of the molecules at the area of the first supporting plate being substantially 45°.
Claim 14
Dependent Claim
52 words
A display device as claimed in claim 2, characterized in that it comprises at least a light source whose light is incident on the liquid crystalline material and is reflected dependent on the optical state of the liquid crystalline material, and in that the light thus reflected is imaged via projection means.
Claim 15
Dependent Claim
39 words
A display device as claimed in claim 1, characterized in that the transmission/voltage characteristic curves for red, green and blue or at least two other composite colours extend substantially parallel through at least a part of the voltage range.
Claim 16
Dependent Claim
26 words
A display device as claimed in claim 14, characterized in that the drive section is provided with a voltage compensation circuit for at least one colour.
Claim 17
Dependent Claim
23 words
A display device as claimed in claim 15, characterized in that the extra layer of birefringent material comprises polymethyl methacrylate and polyvinylidene fluoride.
Claim 18
Dependent Claim
23 words
A display device as claimed in claim 15, characterized in that the second supporting plate is provided with a layer of reflecting material.
Claim 19
Dependent Claim
48 words
A display device as claimed in claim 15, characterized in that the device comprises a polariser and an analyser, the angle between the direction of polarisation of the polariser and the direction of orientation of the molecules at the area of the first supporting plate being substantially 45°.
Claim 20
Dependent Claim
52 words
A display device as claimed in claim 15, characterized in that it comprises at least a light source whose light is incident on the liquid crystalline material and is reflected dependent on the optical state of the liquid crystalline material, and in that the light thus reflected is imaged via projection means.
Claim 21
Dependent Claim
23 words
A display device as claimed in claim 14, characterized in that the extra layer of birefringent material comprises polymethyl methacrylate and polyvinylidene fluoride.
Claim 22
Dependent Claim
23 words
A display device as claimed in claim 14, characterized in that the second supporting plate is provided with a layer of reflecting material.
Claim 23
Dependent Claim
48 words
A display device as claimed in claim 14, characterized in that the device comprises a polariser and an analyser, the angle between the direction of polarisation of the polariser and the direction of orientation of the molecules at the area of the first supporting plate being substantially 45°.
Claim 24
Dependent Claim
52 words
A display device as claimed in claim 14, characterized in that it comprises at least a light source whose light is incident on the liquid crystalline material and is reflected dependent on the optical state of the liquid crystalline material, and in that the light thus reflected is imaged via projection means.
Claim 25
Dependent Claim
23 words
A display device as claimed in claim 1, characterized in that the extra layer of birefringent material comprises polymethyl methacrylate and polyvinylidene fluoride.
Claim 26
Dependent Claim
23 words
A display device as claimed in claim 24, characterized in that the second supporting plate is provided with a layer of reflecting material.
Claim 27
Dependent Claim
48 words
A display device as claimed in claim 24, characterized in that the device comprises a polariser and an analyser, the angle between the direction of polarisation of the polariser and the direction of orientation of the molecules at the area of the first supporting plate being substantially 45°.
Claim 28
Dependent Claim
52 words
A display device as claimed in claim 24, characterized in that it comprises at least a light source whose light is incident on the liquid crystalline material and is reflected dependent on the optical state of the liquid crystalline material, and in that the light thus reflected is imaged via projection means.
Claim 29
Dependent Claim
23 words
A display device as claimed in claim 1, characterized in that the second supporting plate is provided with a layer of reflecting material.
Claim 30
Dependent Claim
48 words
A display device as claimed in claim 28, characterized in that the device comprises a polariser and an analyser, the angle between the direction of polarisation of the polariser and the direction of orientation of the molecules at the area of the first supporting plate being substantially 45°.
Claim 31
Dependent Claim
52 words
A display device as claimed in claim 28, characterized in that it comprises at least a light source whose light is incident on the liquid crystalline material and is reflected dependent on the optical state of the liquid crystalline material, and in that the light thus reflected is imaged via projection means.
Claim 32
Dependent Claim
48 words
A display device as claimed in claim 1, characterized in that the device comprises a polariser and an analyser, the angle between the direction of polarisation of the polariser and the direction of orientation of the molecules at the area of the first supporting plate being substantially 45°.
Claim 33
Dependent Claim
52 words
A display device as claimed in claim 31, characterized in that it comprises at least a light source whose light is incident on the liquid crystalline material and is reflected dependent on the optical state of the liquid crystalline material, and in that the light thus reflected is imaged via projection means.
Claim 34
Dependent Claim
52 words
A display device as claimed in claim 1, characterized in that it comprises at least a light source whose light is incident on the liquid crystalline material and is reflected dependent on the optical state of the liquid crystalline material, and in that the light thus reflected is imaged via projection means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-10-20 | 1996-04-20 | 1996-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-20 | 2000-04-20 | 2000-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-20 | 2004-04-20 | 2004-10-20 | $7700.00 | Window Closed / Lapsed |