Abstract: Alphanumeric images are displayed in common view in one color on a background of a different color using a liquid crystal projection device. The two colors are sufficiently similar so they are not distinguished by the unaided eye of the viewer. A color selective material in the form of glasses is provided to a subclass of the viewers in the audience to enable these viewers to distinguish the alphanumeric subtitles from the background. This material extinguishes either the alphanumeric images or the background, thereby either providing darkened letters on a light background or light letters on a darkened background. The projection and viewing apparatus can be utilized as a motion picture closed captioning system for a mixed audience of hearing impaired and non hearing impaired individuals to permit the hearing impaired to view the subtitles while those individuals not wearing such wavelength selective glasses would not see the subtitles.

Abstract: A method and apparatus for the selective display of motion picture subtitles. A liquid crystal display capable of forming alphanumeric images in one color on a background of a different color. The two colors are sufficiently similar so they are not able to be distinguished by the unaided eye of the viewer. A decoder, a microprocessor and a driver, for example, can be utilized to transfer coded information on standard motion picture film into appropriate subtitles which are then formed on a liquid crystal display. A color selective material is provided to a subclass of the viewers in the audience to enable the viewers in such subclass to distinguish the alphanumeric subtitles from the liquid crystal display background. This material could be provided in the form of glasses which extinguish either the alphanumeric images or the background, thereby either providing darkened letters on a light background or light letters on a darkened background.

Abstract: A harmonic amplifier for a laser beam amplifies a harmonic frequency of the beam. The amplifier generates a series of electric fields across the beam, successive fields being directed oppositely. The spacing between the fields is related to the speed of propagation so as to amplify a particular harmonic. Typically this will be the second harmonic so that the amplifier acts as a frequency doubler. The fields can be provided by an array 6 of electrode pairs positioned on opposite sides of the beam 2 with a voltage generator 8 connected across the sets in alternately opposite sequence.