Abstract: A display apparatus for use in a projection system includes a light source, a beam splitter for splitting light from the source into different color component beams and a deformable mirror device spatial light modulators for each different color beam. The light paths to the beam splitter and modulators are provided within a single prism assembly on which the modulators are mounted.

Abstract: A spatial light modulator in the form of a deformable mirror device receives from a frame store data which has been formatted by a data formatter subsequent to gamma correction in a ROM look-up table. The DMD displays different light levels by being ON for selected periods of a series of durations 4, 8, 16, - - - , 1024 varying in proportion to a basic period multiplied by powers of two. The shortest duration 4 for which the DMD can be turned on is a multiple of the basic period, and the series includes additional durations 5, 6, and 7 in the series between the shortest displayable duration 4 and the next power of two 8. Durations 1, 2, and 3 of less than the shortest displayable duration can be displayed by adjusting the turn-on time of a proportion of the adjacent mirrors. The longest duration for which the mirror can be turned on can be employed twice.

Abstract: A deformable mirror device having a two-dimensional array of mirror elements is driven in such a way to reduce the data rate and remove the need for buffer stores. The mirror elements are loaded row-by-row in response to an n bit video signal in 2.sup.n loading operations. Only n rows are loaded in each loading operation, the other rows remaining in their previous conditions, and the loading continues sequentially down the array. The timing of the loading is such that the duration from loading a given row with a first data bit to loading the same row with the next data bit is proportional to the significance of the first data bit.

Abstract: A spatial light modulator system includes a multi-wavelength light source and three spatial light modulators, two dichroic mirrors are arranged in the light path between the light source and the spatial light modulators so as to direct light within a different wavelength band onto all but one of the spatial light modulators, light to the third spatial light modulator passing through the dichroic mirror onto the third spatial light modulator. Spatially modulated light reflected from the spatial light modulators is combined by the two dichroic mirrors to produce a multi-wavelength spatially modulated output beam. In order to equalize the number of reflections uundergone by spatially modulated light from all the spatial light modulators a reflector is provided in the optical path between the third spatial light modulator and the output beam.

Abstract: A CRT deflection circuit for use in a flying spot telecine scanner comprises a linear amplifier with a resonant flyback circuit and a flyback shift circuit comprising an inductive DC path carrying a DC offset current and a capacitor carrying the raster scan AC current to the flyback circuit. Since the DC offset current is not applied to the flyback circuit, the circuit can fly-back to non symmetrical beam positions, so that the entire scan can be displaced by a shift applied to the input of the amplifier.

Abstract: A spatial light modulator of the so-called deformable mirror device (DMD) type has an array of individual mirror ments (20) arranged in lines. The elements are individually driven to change their orientations. Portions (30) of the mirror ments are non-reflecting such as to divide the mirror elements into substantially equal portions forming a greater number of lines of narrower width, with a view to reducing the subjectively visible line structuring.

Abstract: Color optical output apparatus comprising a color dependent mirror and a pair of optical spacial modulator arrays arranged to deflect light incident thereon, the arrangement being such that an incident polychromatic beam is split by said mirror means into two spectral components, one directed to each array, and said mirror means is arranged also to receive and combine deflected beams from each array to produce a combined optical beam, the spectral response of the mirror means being the same during splitting and combining.

Abstract: A projection system of the kind in which beams of light are projected by a projector onto a screen and the beams are modulated by electronic video information is characterized in that means are provided to vary the intensity of the light falling on different parts of the screen so that to an observer viewing the screen the said light intensity will be perceived as being substantially uniform over substantially the whole are of the screen.

Abstract: A plurality of mountings for locating a shadow mask carrying frame in a color cathode ray tube each comprise one mounting element bonded to the tube wall and another mounting element connected to the frame, which together provide a spring-loaded spigot-and-socket connection. One feature is that the element has a portion bonded to the wall of a compatible material and a second portion of a hard material for low-wear. Another feature is that the element which provides the spigot has a recess therearound within the thickness of the wall into which the other element extends in order to save space.