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1. (WO1997019385) ILLUMINATION SYSTEM, LINEAR POLARIZER FOR SUCH AN ILLUMINATION SYSTEM AND DISPLAY DEVICE COMPRISING SUCH AN ILLUMINATION SYSTEM
Latest bibliographic data on file with the International Bureau

Pub. No.: WO/1997/019385 International Application No.: PCT/IB1996/001215
Publication Date: 29.05.1997 International Filing Date: 13.11.1996
IPC:
G02B 5/30 (2006.01) ,G02F 1/1335 (2006.01) ,G02F 1/13357 (2006.01)
G PHYSICS
02
OPTICS
B
OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
5
Optical elements other than lenses
30
Polarising elements
G PHYSICS
02
OPTICS
F
DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH IS MODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THE DEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY, COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g. SWITCHING, GATING, MODULATING OR DEMODULATING; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
1
Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
01
for the control of the intensity, phase, polarisation or colour
13
based on liquid crystals, e.g. single liquid crystal display cells
133
Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
1333
Constructional arrangements
1335
Structural association of optical devices, e.g. polarisers, reflectors, with the cell
[IPC code unknown for ERROR IPC Code incorrect: invalid subgroup (0=>999999)!]
Applicants:
PHILIPS ELECTRONICS N.V. [NL/NL]; Groenewoudseweg 1 NL-5621 BA Eindhoven, NL
PHILIPS NORDEN AB [SE/SE]; Kottbygatan 7 Kista S-164 85 Stockholm, SE (SE)
Inventors:
BROER, Dirk, Jan; NL
VAN HAAREN, Johannes, Albertus, Matthijs, Maria; NL
MOL, Grietje, Neeltje; NL
LEENHOUTS, Frans; NL
Agent:
VAN DER VEER, Johannis, L.; Internationaal Octrooibureau B.V. P.O. Box 220 NL-5600 AE Eindhoven, NL
Priority Data:
95203209.222.11.1995EP
Title (EN) ILLUMINATION SYSTEM, LINEAR POLARIZER FOR SUCH AN ILLUMINATION SYSTEM AND DISPLAY DEVICE COMPRISING SUCH AN ILLUMINATION SYSTEM
(FR) SYSTEME D'ECLAIRAGE, POLARISEUR LINEAIRE DESTINE A UN TEL SYSTEME ET DISPOSITIF D'AFFICHAGE COMPRENANT CE SYSTEME
Abstract:
(EN) The application relates to an illumination system comprising a fluorescent lamp and a broadband, cholesteric polarizer. Such a polarizer contains a layer of a polymeric material having a cholesteric order, which material is ordered in such a way that the axis of the molecular helix extends at right angles to the layer. The broadband character of the polarizer is obtained by causing the pitch of the molecular helix to increase from a minimum value at a first surface of the cholesteric layer to a maximum value at a second surface of the layer. In accordance with the invention, the polarizer should be positioned in the illumination system in such a manner that the cholesteric layer is directed towards the fluorescent lamp with its first surface. In addition, the value of the product pmax.ne of the maximum value of the pitch in the cholesteric layer pmax and of the extraordinary refractive index ne must range between 0.61 micron and 0.76 micron. By virtue of these measures, the illumination system has a surprisingly low viewing-angle dependence of the lightness and the color. The application further relates to a linear polarizer for use in this illumination system as well as to a display device which comprises such a linear polarizer.
(FR) La demande se rapporte à un système d'éclairage comprenant une lampe fluorescente ainsi qu'un polariseur cholestérique à large bande. Un tel polariseur contient une couche d'un matériau polymère présentant un ordre cholestérique de manière à ce que l'axe de l'hélice moléculaire s'étende à angle droit par rapport à la couche. Le caractère à large bande du polariseur s'obtient en provoquant l'augmentation du pas de l'hélice moléculaire, d'une valeur minimum au niveau d'une première surface de la couche cholestérique, à une valeur maximum au niveau d'une seconde surface de la couche. Selon l'invention, on doit positionner le polariseur dans le système d'éclairage de telle manière que la couche cholestérique soit dirigée vers la lampe fluorescente en présentant sa première surface. En outre, la valeur du produit pmax.ne de la valeur maximum du pas dans la couche cholestérique pmax et de celle de l'indice ne extraordinaire de réfraction doit se situer entre 0,61 et 0,76 micron. Grâce à ces mesures, dans ce système d'éclairage la luminosité et la couleur dépendent pour une part étonnamment faible de l'angle de vision. L'application se rapporte en outre à un polariseur linéaire utile dans ce système d'éclairage ainsi qu'à un dispositif d'affichage comprenant un tel polariseur.
Designated States: CN, JP
European Patent Office (AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE)
Publication Language: English (EN)
Filing Language: English (EN)
Also published as:
EP0804749JPH10513578 CN1169188