1988-03-25
1989-09-19
Arnold, Bruce Y.
350356, 350386, 350403, G02F 1055, G02F 101
Patent
active
048675431
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention concerns improvements in or relating to spatial light modulators. Such modulators comprise an array of individual modulating elements each of which modifies incident light to provide overall spatial modulation in amplitude, polarization, or phase. These devices have application, for example, to image processing, optical signal processing, page composition for optical data storage, and electrical chip-to-chip interconnection.
BACKGROUND ART
Of spatial light modulators considered to date, those of the liquid crystal light valve type appear to have been the most promising. In devices of this type, a layer of liquid crystal material is retained between two electrode coated substrates. One of the electrode coatings is patterned to provide an array of individually addressable electrode elements each corresponding to a cell of the liquid crystal medium. In one common construction, the liquid crystal material is of the nematic type and the molecules are aligned in a twisted formation--each cell thus behaves as a twisted nematic (Schadt-Helfrich) light valve when combined with a sheet polarizer. Useful application of these devices is however limited by the relatively slow response of the liquid crystal media to applied voltage. Modulation bandwidths up to a maximum of a few MHz only have been reported.
DISCLOSURE OF THE INVENTION
The present invention is intended to provide an alternative construction for spatial light modulators, in particular a construction capable of faster response and thus offering wider modulation bandwidth.
In accordance with the invention thus there is provided a spatial light modulator comprising: a sheet layer of solid electro-optic material having at one surface thereof an array of parallel paired electrode elements, and, having at the other surface thereof first light reflecting means: an integrated circuit array of individual driver circuits, each circuit aligned with, and connected to, a corresponding pair of the element electrodes aforesaid; and, optical interface means arranged relative to the sheet layer to direct polarized light onto each array element.
It is convenient to employ, as solid materials, an electro-optic ceramic material. Lead-doped lanthanum zirconate titanate (PLZT) ceramic material, in particular, are preferred, these being readily available, relatively inexpensive and easy to prepare. These materials exhibit exceptionally high electro-optic coefficients (quadratic effect) and thus promise to provide efficient modulating media.
The paired electrodes aforementioned, at one surface of the sheet layer, may be deposited thereon Alternatively, and to provide improved efficiency, these electrodes may be embedded in this one surface, providing thus a more effective localization and concentration of electric field when voltage is applied.
Preferably, the sheet layer and integrated circuit array are both rigid and thus self-supporting, the array circuits and array elements then being aligned and interconnected by matching arrays of solder bumps.
Conveniently, the optical interface means may comprise a micro-lens array. This likewise may be aligned with the array elements by means of further matching arrays of solder bumps. Alternatively, the optical interface means may be provided by an array of optical fibers.
The principal advantage of the invention, that of faster response, is inherent in the use of electro-optic solids materials. This and other advantages of the invention and preferred embodiments will be apparent from the description that follows hereinafter.
BRIEF INTRODUCTION OF THE DRAWINGS
In the drawings accompanying this specification:
FIG. 1 is an exploded perspective view of a spatial light modulator constructed in accordance with this invention;
FIG. 2 is a cross-section of an electro-optic modulating element taken along section I--I of FIG. 1 preceding;
FIG. 3 is a cross-section also of an electro-optic modulating element, a variant of that shown in the previous figure; and,
FIG. 4 is a schematic illustration of
REFERENCES:
patent: 3744878 (1973-07-01), Kiemle et al.
patent: 3806228 (1974-04-01), Imagawa
patent: 4367925 (1983-01-01), Sprague et al.
patent: 4371892 (1983-02-01), Mir
patent: 4377753 (1983-03-01), Mir
patent: 4569573 (1986-02-01), Agostinelli
patent: 4618819 (1986-10-01), Mourou et al.
S. H. Lee et al., "Two Dimensional Silicon/PLZT Spatial Light Modulators: Design Considerations and Technology" Opt. Eng 25, pp. 250-260 (Feb. 1986).
S. C. Esener et al. "One Dimensional Silicon/PLZT Spatial Light Modulators" Opt. Eng. 26 pp. 406-413 (May 1987).
Optical Engineering, vol. 25 No. 2 (Feb. 1986) Soc. of Photo-Optical Instrumentation Engineers, S. H. Lee et al., "Two-Dimensional Silicon PLZT Spatial Light Modulators: Design Considerations and Technlogy", pp. 250-260.
Xerox Disclosure Journal, vol. 3, No. 1, Jan./Feb. 1978 (New York, U.S.) D. L. Camphausen, "Electron Beam Display Target Using Edge Mode Effect" pp. 59-60.
Patent Abstracts of Japan, vol. 9, No. 148 (P-366)(1871) Jun. 22, 1985.
Patent Abstracts of Japan, vol. 8, No. 48 (p. 258)(1485) Mar. 3, 1984.
Bennion Ian
Stewart William J.
Whatmore Roger W.
Arnold Bruce Y.
Plessey Overseas Limited
Shafer R. D.
LandOfFree
Spatial light modulator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Spatial light modulator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spatial light modulator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-364683