Abstract: The present invention relates to a piezoelectric device of a multi-layered structure on which first electrodes and second electrodes are sequentially stacked on a piezoelectric polymer and single surfaces or both surfaces of piezoelectric polymer. In accordance with the present invention, the vibration response characteristics of the piezoelectric polymer can be improved by using the graphene or the composite thereof as a surface electrode material to the piezoelectric polymer; and, there are effects that the response characteristics of the piezoelectric device are excellent and the reliability thereof is excellent by forming a second electrode having an excellent conductivity and a protection electrode thereof.

Abstract: A projection engine having an illuminating system comprising: a light source for illuminating light; a reflecting mirror for reflecting only light which does not pass through a hole among light emitted from the light, wherein said reflecting mirror has a hole in the center portion thereof; a parabolic mirror for returning and irradiating the light emitted from the light source and the light returned from the reflecting mirror; a flyeye lens for making light emitted from the light source and the reflecting mirror uniform so as to let light irradiated with uniform brightness; and a relay lens for transmitting light passed through the flyeye lens; a color separation/combination system for separating light from the illuminating system into R, G and B components and then combining them; an imager for affording images corresponding to the R, G and B components of light separated by the color separation/combination system; and a projection lens system for projecting light from the imager to a screen to form an image

Abstract: Disclosed is an apparatus for projection display using reflection type LCDs. The apparatus for projection display using reflection type LCDs according to the invention comprises an illuminating device including a lamp and a polarizing element for illuminating S wave or P wave, a color splitter/synthesizer, including the reflection type LCDs for providing an image corresponding to an inputted image and converting a polarizing state of incident light when reflecting the light, a retarder stack for differentiating the polarized state of a predetermined color from the incident light, and polarizing beam splitters composed of a material having a photoelastic constant less than 0.03×10−6 mm2/N at a wavelength of 589.3 nm and a minimum transmittance higher than 90% in transmitting the thickness of 25 mm at a wavelength ranged 0.42 &mgr;m-0.

Abstract: A projection system in which the structure of a polarizing beam splitter is improved to eliminate the deterioration of a polarizing plate occurring in incidence of polarized light using the polarizing plate so that the degradation of the projection system can be prevented and life time thereof can be prolonged.