A projection beam supplied by a projector is incident on a beam splitter in the form of a cholesteric filter. The cholesteric filter reflects circularly polarized radiation having a wavelength which corresponds to the pitch of the molecular helix and having a direction of rotation which corresponds to the direction of the molecular helix to a reflector. The circular direction of polarization reflected by the cholesteric filter is inverted on the reflector so that the beam is subsequently passed to the screen by the cholesteric filter.
A projector employing multiple organic electroluminescence (OEL) image panels, in which each image panel is made with multiple light-emitting OEL components. Each light-emitting OEL component represents one image element. The OEL component is capable of emitting individual prime colors, red (R), green (G) or blue (B), or producing white light which is then made to passes through color filters to produce RGB colors. The new structure for the projector provides the features of downsized dimensions, luminous efficiency and light-focusing capability.
A rear projection system provides for reduced cabinet depth by folding the optical path with polarization sensitive mirrors. In one aspect, the projector outputs linearly polarized light to a quarter-wave polarizing sheet, which circularly polarizes the projector output. A mirror directs the projected light back through the quarter-wave material to a polarization-dependent reflector. The light has a reflective polarization state. The polarization-dependent reflector reflects the light back to the quarter-wave material and mirror. Upon traversing the path a second time, the light is in a transmissive polarization state.
A retractable screen system suitable for portable, hand held computing and communication units joins a number of optical sheets to form a rollable, extendible and retractable projection sheet. The resulting folded optical system provides a lightweight, portable unit. Telescoping arms allow the screen to be extended and stowed quickly and easily. High screen resolution is afforded by multiple mechanisms that scan concurrently. Beam indexing of the screen permits the precise alignment via feedback, and an embodiment fit for military, command and control applications.