Abstract: The invention relates to a handheld projection system (10) comprising a projection device (14, 18, 20) for projecting an image onto a projection surface (24). The projection device has at least two drive power modes associated with different qualities of the projected image. The handheld projection system further comprises a selection device (17) for selecting one of said at least two drive power modes on the basis of the currently selected power source of the system, so that the quality of the projected image is adjusted on the basis of the power source of the handheld projection system. The handheld projection system according to the invention may easily be adapted to different situations of usage involving different requirements when it comes to projected image quality and device properties.

Abstract: The invention relates to a liquid crystal display device (10), comprising a spectral trim filter (18) arranged in the light path between the backlight system (14) and the LCD filter panel (12). The trim filter is adapted to reduce the amount of illumination light within selected wavelength ranges in order to enhance the color gamut of the display. The trim filter is also adjustable between a filtering state for wide gamut and a transmitting state for high brightness.

Abstract: Power is saved in a color display system (200) by sacrificing color rendering capability in favor of brightness capability. The system (200) comprises a plurality of light emitters (202,204,206). The emitters are fed with a respective initial electric power input which adds up to a first total electric power input, whereby each light emitter provides an initial first color intensity, a second color intensity and a third color intensity, respectively, which, in combination, are perceivable to the human eye as an initial total brightness. Power input is then reduced to a second total power input by feeding each light emitter with a respective second electric power input, whereby the second total power input that is less than said first total power input is obtained.

Abstract: An illumination system includes a light guide having an entrance face, an exit face and an aperture in which a light source can be arranged Various elements are arranged in the light guide to increase the angle of light beams incident in the light guide with respect to the optical axis of the system and to create a homogeneous illumination at the exit face of the light guide. With this arrangement, the length of a given light guide is reduced, making the illumination system smaller, lighter and more compact with even illumination and a high optical efficiency. The illumination system can be included in a display system.

Abstract: The invention relates to a projection device for projecting an image, comprising an illumination means (1) having an entrance (13) for entering light from a light source, a polarization-selective mirror (3) for transmitting a first polarization component (42) of the light to a display panel (4) and reflecting a second component (43) back to the illumination means (1), and a display panel (4) for selecting colour components of the first polarization component for projection at a projection means (7). The display panel comprises a dichroic filter means (5) for filtering colour components of the first polarization component (42) and a controllable reflective means (6) for changing the state of polarization of the filtered colour components depending on a control signal and for reflecting the filtered colour components back to the polarization-selective mirror (3).

Abstract: A scrolling colour projection system comprising a lamp (4) with a pulsed drive current (20) and a colour scanner (6, 8a, 8b, 8c, 9) for generating a light beam (5b) with a plurality of scrolling colour fields, which is arranged to illuminate a display device (3) to produce a projection of an image generated by the display device. The system further includes a filtering element (31) arranged in the light path between the lamp and the projected image, and the transmission of the filtering element (31) is synchronized with the lamp current so as to cancel an intensity peak in the lamp flux. The filtering element thus effectively removes the impact of the current pulse on the light intensity, resulting in a constant intensity in the projected image, and avoiding any interference patterns.

Abstract: In an image projection device, interferences between the light source and the light modulator leading to visible interferences in the projected image are suppressed by an interference cancellation circuit that pre-corrects the control signal that includes the image data that is to be projected.

Abstract: An optical device for processing radiation that includes a beam splitter and a plurality of radiation processing parts arranged to process the characteristics of different radiation components separately, The polarizing beam splitter includes a wire grid polarizer, a first transparent plate arranged adjacent one side of the polarizer and a second transparent plate arranged adjacent the other side. Each of the first and second plates have substantially equal optical thickness profile.

Abstract: The invention relates to a projection display device comprising an illumination system having a light source and an optical guiding means for providing an illumination beam, and an image display system for modulating the illumination beam with image information and projecting the image on a screen, and means for selectively transmitting a portion of the illumination beam having a desired characteristic to the image display system, and means for feeding back an unused portion of the illumination beam to the illumination system for re-illumination of the image display system. In order to improve the efficiency of the projection display device, a reflection means is provided at a portion of an entrance surface of the light-guiding means and the unused portion of the illumination beam is fed back into the light-guiding means.

Abstract: The invention relates to a projection display device comprising an illumination system having a light source and an optical guiding means for providing an illumination beam, an image display system comprising a display panel for modulating the illumination beam with image information and projecting the image on a screen, and color filter means provided on a wheel, rotatably mounted at its hub, for transmitting colored portions of the illumination beam for illuminating the display panel. In order to simplify the manufacture of the projection display device, the color filter wheel is provided with one or more cholesteric layers for reflecting a portion of the illumination beam not having a predetermined color and having a circular polarization corresponding to a first direction.

Abstract: A projection device comprises a projector (1) for providing a light beam (3, 13) to be projected in polarized light. A adjustable liquid crystal element (4) for changing the direction of polarization is arranged between the projector (1) and the transmissive projection screen (2). The transmissive projection screen (2) comprises a polarizing diffusion layer (9). The extent of changing the direction of polarization by the adjustable liquid crystal element (4) for changing the direction of polarization is adjustable. The extent of changing the direction of polarization and hence the extent of diffusion in the transmissive projection screen (2) is adjustable by way of adjusting the voltage from a voltage source which is coupled to the adjustable liquid crystal element (4) for changing the direction of polarization.

Abstract: The invention relates to a projection display device comprising a illumination system having a light source and an optical bar for providing an illumination beam, an image display system comprising a display panel for modulating the illumination beam with image information and projecting the image on a screen, and a color filter provided on a wheel, rotatably mounted at its hub, for transmitting colored portions of the illumination beam for illuminating the display panel. In order to improve the efficiency of the projection display device, the color filter comprises adjacent spiral-shaped filter portions for simultaneously illuminating portions of the display panel by the colored portions of the illumination beam so that the portions of the display panel are consecutively illuminated by the colored portions of the illumination beam.

Abstract: A projection screen providing an improved contrast between projected light and ambient light, which projection screen includes a light-absorbing layer and an active layer located in front of said light-absorbing layer. The active layer is transparent to light having a first direction of polarization and reflective to light having a second direction of polarization. The reflecting polarizing layer may be provided between the active layer and the light-absorbing layer.

Abstract: An image projection system includes an illumination system and an image display system with at least one reflective image display panel for modulating. An illumination beam is supplied by the illumination system with image information and a projection lens system. The illumination system has an extra optical system that at least partly re-illuminates the image display system with light reflected by the reflective image display panel to the illumination system. The extra optical system redistributes light coming from a pixel of the image display system across a plurality of pixels of the image display system.

Abstract: An optical device for processing radiation, said device comprising a polarising beam splitter (4, 6,10,16) and a plurality of radiation processing parts (8,18, 20) arranged to process the characteristics of different radiation components separately, wherein the polarising beam splitter comprises a wire grid polariser having first and second sides, a first transparent plate arranged adjacent one side of the polariser and a second transparent plate arranged adjacent the other side. Each of said first and second plates have an optical thickness profile which is substantially equal.

Abstract: A projection device adjusts the color balance for a white portion of an image. A light source drives one or more electro-optical light modulation panels. A light control device comprising an LCD provided with a single electrode is associated with and cooperates with the light modulation panel(s) and is adjustable to increase output of one or more of the light modulation panels in order to adjust the color balance of the white portion of the image.

Abstract: A projection device comprises a projector (1) for providing a light beam (3, 13) to be projected in polarized light. A means (4) for changing the direction of polarization is arranged between the projector (1) and the transmissive projection screen (2). The transmissive projection screen (2) comprises a polarizing diffusion layer (9). The extent of changing the direction of polarization by the means (4) for changing the direction of polarization is adjustable. The extent of changing the direction of polarization and hence the extent of diffusion in the transmissive projection screen (2) is adjustable by way of adjusting means (10, 11, 12) which are coupled to the means (4) for changing the direction of polarization. The means for changing the direction of polarization preferably comprises an adjustable liquid crystal element (4).

Abstract: The invention relates to a projection display device comprising an illumination system having a light source and an optical guiding means for providing an illumination beam, and an image display system for modulating the illumination beam with image information and projecting the image on a screen, and means for selectively transmitting a portion of the illumination beam having a desired characteristic to the image display system, and means for feeding back an unused portion of the illumination beam to the illumination system for re-illumination of the image display system. In order to improve the efficiency of the projection display device, a reflection means is provided at a portion of an entrance surface of the light-guiding means and the unused portion of the illumination beam is fed back into the light-guiding means.

Abstract: The invention relates to a projection display device comprising an illumination system having a light source and an optical guiding means for providing an illumination beam, an image display system comprising a display panel for modulating the illumination beam with image information and projecting the image on a screen, and color filter means provided on a wheel, rotatable mounted at its hub, for transmitting colored portions of the illumination beam for illuminating the display panel. In order to improve the efficiency of the projection display device, the color filter means comprises adjacent spiral-shaped filter portions for simultaneously illuminating portions of the display panel by the colored portions of the illumination beam so that the portions of the display panel are consecutively illuminated by the colored portions of the illumination beam.

Abstract: The invention relates to a projection display device comprising an illumination system having a light source and an optical guiding means for providing an illumination beam, an image display system comprising a display panel for modulating the illumination beam with image information and projecting the image on a screen, and color filter means provided on a wheel, rotatably mounted at its hub, for transmitting colored portions of the illumination beam for illuminating the display panel. In order to simplify the manufacture of the projection display device, the color filter wheel is provided with one or more cholesteric layers for reflecting a portion of the illumination beam not having a predetermined color and having a circular polarization corresponding to a first direction.