Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Taketoshi Hibi

Ken Onishi

Tomohiro Ueda

Masako Asamura

Junko Ishimoto

Tohru Inoue

Sadayuki Inoue

Tatsuo Yamasaki

Satoshi Kurahashi

Nobuyoshi Okumura

Shinji Okamori

Yuzo Nakano

Hiroshi Sasaki

Kihei Ido

Junichi Nose

Akihisa Miyata

Keiji Hatanaka

Hideki Kaneko

Masako Yamada

Shinobu Ueda

Kenji Maeno

Akiyoshi Hirano

Takashi Shiroshita

A display apparatus displaying an image includes a light source, a light valve, a light cross-section converter and a light scanning mechanism. The light valve has a screen formed of a plurality of pixels. The light cross-section converter converts light emitted from the light source into illumination light having a cross section enough to illuminate at least one pixel at a time. The light scanning mechanism controls a direction of travel of the illumination light in such a way that the illumination light scans the plurality of pixels. The light scanning mechanism controls at least one of sequence, speed, and number of times of scanning where the illumination light scans the plurality of pixels, so that a desired profile of distribution of illuminance is obtained over an entire surface of the screen for a time period not longer than one frame time of an image.

Method of illumination and display apparatus

A projection-type display apparatus that has enhanced the sense of being present by adaptively adjusting, with a simple constitution, projection illumination, depending on an image signal, without causing color changes and by increasing apparent contrast. The projection-type display apparatus includes a light source, a liquid crystal light valve that modulates light emitted from the light source by turning its light polarization plane, and a projection lens that projects the light modulated by the liquid crystal light valve onto a projection surface, wherein a pivotable light polarizer is arranged between the light source and the liquid crystal light valve. The black level of an image is adjusted by adaptively pivoting the light polarizer in response to the image signal.

Projection-type display apparatus

Data separating means extracts intra-frame or intra-field encoded blocks from an intra-frame or intra-field encoded, and inter-frame or inter-field encoded digital video signal, and a digital audio signal contained in an input bit stream. Error correction code appending means appends error correction codes to the extracted intra-encoded blocks. Recording means records the data having the error correction code appended, in special replay data recording areas predefined on the magnetic recording tape. During fast replay or slow replay, error correction is achieved even for the replay signal with a low output level and a poor symbol rate.

Device for recording digital video and audio signals in designated areas of a recording medium in a predetermined track format

The presented invention relates to a light deflector. The light deflector defining a light-incident side and a light-exiting side, the deflector comprising a plurality of reflector() arranged side-by-side in a predetermined orientation, each reflector having, a first reflection face(A), provided on the deflector light-incident side, for reflecting incident light so as to focus the light, and a second reflection face (B), provided on the deflector light-exiting side, for reflecting light reflected by the first reflection face of an adjacent reflection means(). In accordance with the present invention, light utilization efficiency can be raised.

Light deflector and rear-projection screen

A projection-type display apparatus for projecting an image onto a screen includes a light source, a signal processing unit for processing an input image signal to output a first image signal representing first primary-color information R, G, and Brepresenting values of red, green, and blue components of an image to be projected, a signal conversion unit for converting the first image signal into a second image signal representing a coefficient M which depends on luminance of the image to be projected defined by the first primary-color information R, G, and B, and into a third image signal representing second primary-color information R=R/M, G=G/M, and B=B/M. The projection-type display apparatus also includes a first light valve for modulating light received from the light source in accordance with the coefficient M, the light changing in color among red, green, and blue, a second light valve for further modulating the light received from the first light valve in accordance with the second primary-color information R, G, and Bin sequence, and a projection unit for throwing the light received from the second light valve onto the screen.

Projection display apparatus and method for projecting image onto a screen

In a digital VTR having a certain recording bit rate, within a range not higher than a remaining data rate after recording the bit stream, first HP data Dis recorded in first specific regions, and second HP data Dis recorded in second specific regions in specific tracks. In middle-speed and high-speed fast replay, the magnetic tape is transported continuously at a middle-speed or high-speed higher than the standard speed for normal replay, and the first HP data Dis used in common, and at a low-speed fast replay of about twice the normal speed, the speed of the magnetic tape is alternated between a speed near the standard speed for normal replay, and a speed near the low-speed fast, and at the speed near the standard speed, the second HP data disposed in the second specific regions in the specific tracks and the first HP data disposed in the first specific regions in the specific tracks are both replayed.

Digital VTR

A plurality of reflecting mirrors () extending in the vertical direction of a screen are provided in parallel as appropriate between a light incident surface and a light exiting surface. The reflecting mirrors () each have a shape of parabolic cylinder, for condensing light on substantially one line. Light rays (L) are reflected from a concave mirror part on the inner surface of one of the reflecting mirrors (), and are reflected again from a convex mirror part of an adjacent one of the reflecting mirrors (), to be emitted to the outside. Being reflected from the inner surface of one of the reflecting mirrors (), the light rays (L) are condensed on a predetermined focal point (FP), and are then emitted while diffusing. Thus obtained is a diffuser panel for a rear projection screen capable of contributing to improved clarity of images.

Diffuser panel for rear projection screen and such rear projection screen

The illumination optical system for guiding a light emitted from a light source to an object to be illuminated along an optical path includes a first reflecting mirror reflecting a part of a light which is moving in a forward direction along the optical path to move away from the light source and a second reflecting mirror reflecting a part of a light which is reflected from the first reflecting mirror and moving in a reverse direction along the optical path to approach the light source. The first reflecting mirror has an opening facing a light-entering surface of the object to be illuminated, and the second reflecting mirror has a window that allows the light emitted from the light source to pass therethrough, whereby an optical cavity is constituted by the first and second reflecting mirrors.

Illumination optical system and projection-type display apparatus

A digital VTR for magnetically recording and replaying a bit stream, includes a detector, an extractor, a mode designator, and an output unit. The detector detects intra-picture data in the bit stream being replayed from tracks in a magnetic medium. The extractor extracts the intra-picture data from the bit stream based on output from the detector. The mode designator designates one of a normal replay and a slow replay as a replay mode. The slow replay is replay performed at a speed slower than normal replay. The output unit stores the extracted intra-picture data, and outputs only the extracted intra-picture data as replay picture data when the slow replay mode is designated.

Digital VTR for recording and replaying data depending on replay modes

In a beam current limiting circuit for a video projector, an average current is limited under closed loop control containing an anode current detection circuit. On the other hand, a cathode current detection circuitcomprises a first resistor and a second resistor in series to a cathode current circuit and detects a cutoff current at the voltage across the first resistor and an average current at the voltage across the second resistor. An offset addition circuitis provided for correcting the detection value of the average current based on the maximum value of detected cathode current, and beam current is limited. Further, meansfor detecting time change of anode current is provided and if the current value does not change for a long time, the beam current is limited to a smaller value.

Beam current limiting circuit for use in a video projector

A projection television has a unit for reflecting OFF light not advancing toward a screen of light emitted by a reflection type light modulating element and a unit for controlling the amount of the reflecting OFF light and returns the OFF light which has not been used in a conventional device to the light source to reuse the OFF light. This configuration increases the utilization efficiency of the light and, as a result, can realize a powerful projection television having a bright projection image.

Light source device and projection television

A screen-noise eliminating apparatus including beam-spot-length control means for increasing or decreasing the vertical length of a beam spot on a display screen generated by an electron of a cathode-ray tube for displaying a TV signal; vertical enhancement means for enhancing a given vertical-direction spatial frequency characteristic of said TV signal; and noised elimination control means for controlling said beam-spot-length control means and said vertical enhancement means so as to compensate according to the increase of decrease of said beam spot length.

Screen-noise eliminating apparatus and cathode-ray tube display apparatus

In a color image projection apparatus using a color wheel to illuminate a spatial optical modulator with light in color sequence, light reflected from the color wheel is added to light having passed through the color wheel, and the combined light is spatially modulated by the spatial optical modulator to form an image. If the light reflected a the incident surface of the color wheel is guided to the exit surface of the color wheel, and combined with the light having passed through the color wheel, the light utilization efficiency is improved. Any type of images can be projected with improved brightness.

Image projection apparatus

Data seperating means extracts intra-frame or intra-field encoded blocks from an intra-frame or inter-field encoded digital encoded, and inter-frame or inter-field encoded digital video signal, and a digital audio signal contained in an input bit stream. Error correction code appending means appends error correction codes to the extracted intra-encoded blocks. Recording means records the data having the error correction code appended, in special replay data recording areas predefined on the magnetic recording tape. During fast replay or slow replay, error correction is achieved even for tile replay signal with a low output level and a poor symbol rate.

Growing community of inventors

Tokyo, Japan

Taketoshi Hibi