Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Light-valve technologies for high-definition television projection displays

: Gerhard-Multhaupt, R.


Displays. Technology and applications 12 (1991), No.3-4, pp.115-28
ISSN: 0141-9382
Journal Article
Fraunhofer HHI ()
high definition television; insulated gate field effect transistors; liquid crystal displays; electrooptic layers; CMOS; deformable light valve control layers; thin film transistors; active-matrix-addressed liquid-crystal light-valve projectors; electron-beam-addressed light-valve projectors; active-matrix addressing; oil-film control layers; metallized viscoelastic layers; deformable micromechanical mirrors; polymer-encapsulated liquid crystals; deformable viscoelastic light-valve control layers; schlieren optical systems; Si-MOSFET active matrices; thin metallized elastomer layers; Si

Light-valve projection offers high resolution with large image areas and high brightness, and it thus appears to be most suitable for HDTV displays. The increasing availability of active-matrix-addressed liquid-crystal light-valve projectors for standard television, and the continuing dominance of 'classical' electron-beam-addressed light-valve projectors for the most demanding professional applications, are the starting points of a survey on the state of the art. After the two groups of light-valve projectors have been briefly reviewed, the major light-valve technologies are explained in some detail. Transmissive and reflective liquid-crystal light valves with various types of addressing are described first; the trend toward active-matrix addressing and high resolution is demonstrated. Commercial light-valve projectors with electrooptic and oil-film control layers are briefly introduced, and alternative technologies, such as metallized viscoelastic layers, deformable micromechanical mirrors, and polymer-encapsulated liquid crystals, are discussed. The author's research on deformable viscoelastic light-valve control layers for use in schlieren optical systems and on Si-MOSFET active matrices for addressing these is reported in some detail. The deformation behaviour of thin metallized elastomer layers has been analysed. Sample MOSFET active matrices with picture-element densities suitable for HDTV have been designed and fabricated. A full-colour schlieren optical projection system is briefly described.