A liquid crystal type video projector is disclosed which has a reflection type optical modulator for effective use of beams from a radiation source such as a lamp or the like. The projector further comprises means for modulating the plane of polarization of a polarized beam entering the radiation source and for reflecting the polarized beam, thereby causing a reflection beam and an optical arrangement. The optical arrangement includes a first polarizing beam splitter for separating the beam from the radiation source into P and S polarized components and for directing the S polarized component to the modulator and a converter for rotating the plane of polarization of the P polarized component and converting into another S polarized component for enhanced efficiency of beam utilization. It further includes a second polarizing beam splitter for reflecting the other S polarized component and directing the other S polarized component and directing to the modulator. The polarizing beam splitters are caused to act as an analyzer for colored reflected beams via a dichroic mirror system.
The invention provides an illumination system that can include a first reflecting mirror arranged on a rear side of a light-emitting portion of the illumination system including an arc tube, and a second reflecting mirror arranged on the front side of the light-emitting portion of an optical system. The system is arranged so that the diameter on a reflecting surface of the first reflecting mirror corresponding to the available marginal light emitted from the light-emitting portion to the rear side of the illumination system is larger than the diameter of the outer surface of the second reflecting mirror and the diameter of the outer surface of the second reflecting mirror is set to a size within the light as the available marginal light reflected by the first reflecting mirror, a reflecting surface of the second reflecting mirror surrounds about half of the front side of the light-emitting portion, and the light emitted from the center of the light-emitting portion and incident on the second reflecting mirror agrees with the normal of the second reflecting mirror.
The present invention provides a projecting device for displaying electrical images. The projecting device comprises an illumination device for emitting a polarized trichrome light of various polarizations, three modulating devices for modulating three polarized monochrome lights to display the same electrical image, a light separating device having two dichroic mirrors perpendicular to two polarization beam splitting mirrors. One dichroic mirror and the two polarization beam splitting mirrors are used for separating the polarized trichrome light into three monochrome lights and passing each monochrome light to a correspondent modulating device for optical modulation. The three modulated lights reflected from the three modulating devices are transmitted to another dichroic mirror and synthesized into an output light beam for displaying the electrical image.
An optical system of an LCD projector includes a light beam splitter for passing only a specific wavelength of light emitted from a light source and reflecting another wavelength. Two reflection type LCDs for a black-and-white signal and a color signal, respectively, are placed in correspondence with the light of the respective wavelengths, split by the light beam splitter. The LCDs either transmit or scatter the light of the respective wavelengths according to whether the particular LCD is turned on or off, so that the resolution can be improved by projecting the LCD for the black-and-white signal together with the LCD for the color signal.
A polarizing beamsplitter (PBS) that can be used with reflective light valve displays includes two polarizing surfaces. A light source projects opposing readout beams onto the polarizing surfaces, which reflect linearly polarized (S or P) components of the readout beams. The polarized readout beams illuminate respective portions of a reflective light valve cell that bears an image intensity pattern. The cell spatially modulates the readout beams' polarization in accordance with the image intensity pattern and reflects the polarization modulated beam back towards the polarizing beamsplitter. The PBS spatially analyzes the readout beams' intensities in accordance with their polarization modulations.
An LCD projector for projecting an image displayed on an LCD of the electrooptic-effect type on a projection screen is disclosed. The LCD projector has a polarization beam-splitting optical system which is disposed in the optical path of a projection beam between a light source and the LCD. The optical system has a plurality of optical subsystems and at least one optical rotator. Each optical subsystem has a reflecting device and a polarization beam splitter arrangement provided with a polarization beam-splitting plane arrangement. The polarization beam splitter arrangement and the beam-splitting plane arrangement are arrangements of one or more polarization beam splitters and of one or more polarization beam-splitting planes, respectively. The beam-splitting plane arrangements provided in the plurality of the optical subsystems are disposed in the optical path of the projection beam and oriented with respect to the projection beam so as to define planes of incidence parallel to each other. The reflecting device is made up of one or more reflectors oriented so that the s-polarized component reflected on the polarization beam-splitting plane arrangement is deflected toward a prescribed region of the incidence surface of the LCD. The optical rotator makes parallel the directions of the s- and p-polarized components delivered from the optical system.
