Abstract: A color corner of a projection system includes a dichroic filter having a flat plate type structure, thereby achieving an improvement in color separation characteristics while allowing easy manufacture of the dichroic filter. The projection system includes an illumination unit for separating an S-polarized light from a non-polarized white light, a polarized beam splitter for transmitting a selected one of the R, G, and B components of the light received from the illumination unit while reflecting the remaining two components of the incident light, and a flat plate type dichroic filter for defining different transmission and reflection optical paths for the separated two light components, respectively, thereby separating the two light components reflected by the polarized beam splitter.

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: Disclosed is a projection lens of a projection display apparatus including a first lens group arranged upstream from a screen, the first lens group having a negative power and including at least one aspherical lens element and at least three spherical lens elements, the lens element of the first lens group spaced away from the screen by a maximum distance having a positive power, a second lens group arranged upstream from the first lens group, the second lens group having a positive power and including a triple cemented lens composed of three lens elements cemented together, and at least one lens element arranged at one side of the triple cemented lens opposite to the screen, and an aperture stop arranged between the first and second lens groups.

Abstract: Disclosed is a color corner of a projection system including a dichroic filter having a flat plate type structure, other than a cube prism type structure, thereby being capable of achieving an improvement in color separation characteristics while allowing an easy manufacture of the dichroic filter, and thus, achieving an improvement in productivity.

Abstract: A lens unit, for a projector, includes a scrambler which converts light input from a lamp into a uniform light. An image lens unit is arranged on an optical path between the scrambler and a liquid crystal display (LCD) panel for generating an image. The image lens unit allows the light passing through the scrambler to be emitted to the entire surface of the LCD panel. A collimating lens is arranged on the optical path between the image lens and the LCD panel and is provided for converting the light passing through the image lens into a parallel beam. The image lens unit consists of a first image lens of a positive power and a second image lens of a positive power.

Abstract: A rear projector employing an image display uses a polymer dispersion liquid crystal (PDLC) panel which suppresses a turbulent reflection due to a high light refractive index. Accordingly, a slim appearance is attained since a light separating/synthesizing system is eliminated, and the resolution and brightness of the image is improved by precisely and easily controlling the change of the light pathway.

Abstract: A wide-projection angle liquid crystal projection lens system including a condensing lens, installed opposite to a light-emitting surface of an image-forming element for emitting image rays to be magnified and projected onto a screen of a projection display system, for converging the image rays incident thereto, a first lens group, installed opposite to a light-emitting surface of the condensing lens, for compensating for chromatic aberration of the image rays converged and emitted from the condensing lens, a second lens group for changing a direction of the image rays emitted from the first lens group, and a third lens group for magnifying the image rays emitted from the second lens group and projecting the magnified image rays to a reflecting mirror. According to the system, the optical axis of the system can be changed over about 90.degree. utilizing the prism provided in the projection lenses, and thus the height and depth of the projection display system is reduced to a minimum.

Abstract: A method for detecting color burst signal amplitude of a composite color image signal for use in an automatic color control circuit includes the steps of separating the burst signal loaded on the chrominance signal into first and second chrominance reference signals having a predetermined phase difference with respect to each other using a carrier signal having an arbitrary burst signal, detecting the squared components of the separated first and second chrominance reference signals respectively, and outputting the amplitude value of the burst signal using a composite signal of the squared components of the detected first and second chrominance reference signals. An apparatus using this method can detect the level of the burst signal regardless of the phase difference between the burst signal and the demodulated carrier.

Abstract: A light source apparatus for generating parallel light is equipped with dual mirrors to compensate for a shadow cast by the lamp itself. The apparatus includes an elliptical reflector and a light source located at the near focal point of the elliptical reflector. A first mirror having an aperture in the center thereof, for reflecting rays emitted directly from the light source back toward the light source, and a second mirror positioned directly in front of the light source, for reflecting the rays reflected from the first mirror and passing the rays through the aperture of the first mirror are provided. A collimating lens is provided for forming parallel light by focusing the rays passed through the aperture of the first mirror, thereby being used as the light source or other element of an optical instrument which requires a highly uniform parallel light source.

Abstract: A parallel light generating apparatus uses two arrayed mirrors. The apparatus includes a parabolic mirror, a lamp located at the focal point of the parabolic mirror, and first and second arrayed mirrors disposed in parallel, each of which is divided into plural portions, with each portion being divided again into parts. A panel is situated between the arrayed mirrors and has a plurality of holes corresponding to each portion of both mirrors, for blocking non-parallel light.

Abstract: A metal halide lamp includes a luminous tube which is sealed and filled with predetermined rare gases and metal halide, a pair of electrodes provided in the inner portion near both ends of the luminous tube, an outer tube which encloses the luminous tube, and a pair of socket connectors electrically connected with the electrodes, wherein the luminous tube cross-section forms an uneven pattern and is pleated along outer and inner surfaces of the luminous tube. The atmospheric pressure in the luminous tube is stabilized to prevent the bending of the arc. Accordingly, the lifetime of the luminous tube is prolonged and high vapor density is obtained, thereby improving luminous efficiency and color rendering by far.

Abstract: A projection lens system for use in a rear type projection television. The system includes a first lens of which at least one surface is aspherical, the center portion of which has little optical power, and the peripheral portion of which has a weak positive optical power. A second lens of the system has a strong positive optical power and a bi-convex shape, wherein at least one of its surfaces is aspherical. A third lens in the system has a strong negative optical power and a bi-concave shape, and has at least one surface that is aspherical. A fourth lens has a strong positive optical power and a bi-convex shape, and at least one aspherical surface. A fifth lens has a weak negative optical power and a meniscus shape, wherein at least one surface is aspherical. The projection lens system reduces the number of lenses required, as compared with the prior art, provides a brighter picture and a greater field angle, and facilitates the correction of chromatic aberrations.

Abstract: The present invention relates to a projection lens system for use in a rear type projection television. The projection lens system includes a plurality of lenses which are sequentially arranged along an optical axis perpendicular to a CRT screen. The system includes: a first lens unit including at least one lens of meniscus form and having a weak positive or weak negative optical power; a second lens unit including one lens with a strong positive optical power and a bi-convex form; a third lens unit including at least one lens having a weak positive or negative optical power, and a further lens having a strong positive optical power; a fourth lens unit having a strong negative optical power and including a meniscus lens that is convex toward the CRT screen and that has a strong negative optical power, the fourth lens unit further including a coolant for cooling a fluorescent surface of the CRT. The optical power of the whole system is largely divided between the second and third lens units.