Patent ID: 6104365
Filing Date: 2000-08-15
Classification: G09G

Abstract:
A light modulating device comprising an addressable matrix of modulating elements, and addressing means for selectively addressing each element in order to vary the transmission level of the element relative to the transmission levels of other elements, the addressing means including spatial and/or temporal dither means for addressing separately addressable spatial bits of each element with different combinations of spatial dither signals and/or for addressing at least part of each element with different combinations of temporal dither signals applied to separately addressable temporal bits corresponding to subframes of different periods to produce a plurality of different transmission levels, and state selection means for switching at least a part of each element between different states corresponding to different transmission levels by means of on and off switching signals, whereby a plurality of different overall transmission levels are obtainable by selection of different combinations of spatial and/or temporal dither signals and switching signals, wherein the state selection means is arranged to additionally apply at least one intermediate switching signal for producing at least one intermediate state in at least one bit of at least one element, including at least one error-producing analogue state, in order to obtain intermediate overall transmission levels and to control such switching such that, for each intermediate overall transmission level requiring at least one error-producing state, periods in which at least part of the element is in the error-producing analogue state alternate with periods in which said part is in a substantially error free state during production of the transmission level.