Uflitfid SIIQIQS Pfitfllt [19] [11] Patent Number: 4 466 702
9 9
Wiener-Avnear et al. [45] Date of Patent: Aug. 21, 1984
[54] LIQUID CRYSTAL LIGHT VALVE WITH [56] References Cited
BIREFRINGENCE COMPENSATION U.S. PATENT DOCUMENTS
3,88l,808 S/l975 G l l. .................... .. 350/335
[75] Inventors: Eliezer Wiener-Avnear, Carlsbad; un er at a
Jan Grinberg, Los Angeles, both of OTHER PUBLICATIONS
Cam‘ Grinberg et al., Optical Engineering, vol. l4, No. 3,
May-Jun. 1975, pp. 217-225.
[731 Assignee: Hugh“ Aircrjm 0°m|m‘y' E1 Primary Exam|'ner—F. L. Evans
Segundo’ Cam‘ Attorney, Agent, or Firm—John Holtrichter, Jr.; A. W.
Karambelas
[21] Appl. No.: 249,753 [57] ABSTRACT
_ This invention is a light valve using birefringent ne-
[22] Flledj Aw‘ 1’ 1981 matic liquid crystals in which compensation for residual
birefringence is achieved by passing light through two
[51] Int. Cl.’ ............................................ .. G02F 1/133 Separate liquid crystal layers having their major optical
[52] U,$, Cl, _ _ , , , _ _ _ _ __ 350/347 R; 350/335; axes aligned perpendicular to one another at the inter-
350/342 face between the two liquid crystal layers. _
Field of Search ................. .. 350/335, 342, 347 R,
