Hitachi, Ltd.

Hitachi Media Electronics Co., Ltd.

Hitachi-lg Data Storage, Inc.

Fumio Haruna

Kouji Kitou

Tomoki Kobori

Tetsunosuke Nakamura

Tsuneyuki Nozawa

Masaru Shimizu

Yuya Ogi

Yoshiho Seo

Toshio Ueda

Nobuaki Kabuto

Yoshihisa Ooishi

Toshimitsu Watanabe

Fumio Inoue

Ryuuichi Someya

Tomoyuki Nonaka

Takeshi Maruyama

Junichi Satoh

Masayuki Hatori

Yasunori Ishii

Tsutomu Kuroiwa

Atsushi Shigeta

A laser projection display device includes: a laser light source drive unit; an attribute amount detection unit for detecting the attribute amount of a picture signal; a light sensor for measuring the light amounts of the laser light sources; and a temperature sensor for measuring the temperatures of the laser light sources. The laser projection display device is configured so that the current vs. light amount output characteristics of the laser light sources with a threshold current and current gain as a parameter are corrected in accordance with the load amount of the picture signal per frame if the change of the attribute amount exceeds a predefined amount; the light sources are driven at a predefined timing of the vertical blanking interval; controls the threshold currents and current gains in accordance with the light amounts; and the threshold currents and current gains are corrected on the basis of the measured temperatures.

Laser projection display device and laser drive control method

A laser beam display device includes: a dimming setting input unit into which any one of the dimming values of plural dimming steps are input; a first dimming processing unit having plural dimming LUTs that store dimming amounts regarding the respective dimming steps with the corresponding gradation levels as indexes; a second dimming processing unit having one gain LUT that holds gains regarding the respective dimming steps and a multiplier that creates the indexes for the respective dimming LUTs by multiplying a video signal by the gains; and a light source drive unit that drives a laser diode on the basis of reference results obtained by referring to the dimming LUTs of the first dimming processing unit. The luminance of the emission beam of the laser diode, which corresponds to the video signal, is dimmed in accordance with a dimming setting input from the dimming setting input unit.

System and methods for laser beam display

The white balance for a high brightness region and a low brightness region is improved in an image display device using MEMS and a laser light source. An image processing unit of the device superposes a signal based on a first measured value of a light quantity at a first temperature on a picture signal, during its blanking period, which is supplied to the laser light source, and superposes a high frequency signal on the picture signal during its effective scanning period. An amplification factor of the light source drive unit is changed so that a second measured value at a second temperature comes close to the first measured value at the first temperature as a target value based on the second measured value at which the light quantity of light generated at the laser light source is measured at the second temperature different from the first temperature on the signal based on the first measured value. By superposition of the high frequency signal, white balance control in a low brightness region for which control is especially difficult is performed with adequate accuracy.

Image display device

A change in the white balance caused due to the temperature is reduced in an image display device using MEMS and a laser light source. An image processing unit of the device superposes a signal based on a first measured value of a light quantity at a first temperature on a image signal to be supplied to the laser light source. An amplification factor of the light source drive unit is changed so that a second measured value at a second temperature comes close to the first measured value at the first temperature as a target value based on the second measured value at which the light quantity of light generated at the laser light source is measured at the second temperature different from the first temperature on the signal based on the first measured value.

Disclosed herein is a discharge lamp lighting device which realizes the minute control of the lighting sequence and electric power of a high-pressure discharge lamp and the control of various anti-error protecting functions by mounting a microcomputer. However, since microcomputer processing typically progresses in accordance with the programs previously recorded on a ROM, various actions of the discharge lamp are controlled in accordance with ROM-recorded data settings. To modify these settings, the contents of the ROM need to be updated. Therefore, a function for communicating with an external device is assigned to the microcomputer so that various data settings can be modified.

Discharge lamp lighting device

There is provided a safe image display apparatus for projecting an image on a screen that can minimize a stimulus to eyes, retinae and optic nerves from projected light entering into the eyes directly. By comparing a displayed image captured by a camera with an input image signal, a changed area is detected as a difference area and, then, a projected image signal is generated wherein a picture area image signal in the input image signal that corresponds to this difference area is masked by a black signal. The obtained projected image signal is projected onto the screen.

Projector type display apparatus

A computing circuit computes a target value of a current to be supplied to a discharge lamp and generates a pulse control signal for superpose a pulse current. Furthermore, the computing circuit controls a current control circuit so that a pulse current is superposed on a lamp current at a predetermined cycle and power supplied to the discharge lamp is kept constant. For that purpose, the computing circuit lowers a DC current level of the lamp current when a pulse current is superposed on the lamp current, and exercises control so that an integrated amount of power at a predetermined cycle is equalized to a predetermined integrated amount of power.

Discharge lamp lighting device and projection type image display apparatus having the same

An image display apparatus includes scanning line control circuits for supplying a scanning voltage Vfor selecting a plurality of electron sources in a unit of line to scan them in the vertical direction to the selected electron sources, a signal line control circuit for supplying a drive voltage Vbased on an image signal to the electron sources of one line, and a signal processing circuit having a correction circuit, and the correction circuit corrects the image signal to add to the drive voltage Van offset for compensating a voltage drop caused by an internal resistance R of a switch circuit in the scanning line control circuit, so that the voltage drop caused by the internal resistance of the switch circuit is compensated to lower or suppress reduction of brightness.

Image display apparatus

A discharge lamp lighting apparatus has a problem that a microcomputer within the apparatus falls down into malfunction due to noises generated in an inside thereof. With such the structure of the discharge lamp lighting apparatus that an operation of a calculation processing circuit, which is built up with the microcomputer, etc., is stopped through stopping the supply of electric power to the calculation processing circuit or bringing it into a sleep mode, it is possible to protecting it from the malfunction, during a time period when high voltage is generated just after starting of lighting of the discharge lamp. Also, with applying a protection processing by means of the calculation processing circuit and also applying an analog protection circuit, in common with, thereby it is possible to ensure reliability thereof further.

Discharge lamp lighting apparatus

In measuring the angle of inclination of a liquid crystal projector with respect to the screen for automatically adjusting a trapezoidal distortion, the calculation of the angle of inclination by determining the distance from the screen using a distance sensor conventionally requires a high distance measurement accuracy and hence an expensive distance sensor. According to the invention, a distance sensor is rotated and the level of the wave reflected from it is observed. The angle of inclination with respect to the screen is detected from the rotational angle associated with the maximum value of the level of the reflected wave thereby to correct the trapezoidal distortion. In this way, the trapezoidal distortion can be adjusted automatically using an inexpensive distance sensor.

Projection-type display apparatus

Disclosed herein is a discharge lamp lighting device which realizes the minute control of the lighting sequence and electric power of a high-pressure discharge lamp and the control of various anti-error protecting functions by mounting a microcomputer. However, since microcomputer processing-typically progresses in accordance with the programs previously recorded on a ROM, various actions of the discharge lamp are controlled in accordance with ROM-recorded data settings. To modify these settings, the contents of the ROM need to be updated. Therefore, a function for communicating with an external device is assigned to the microcomputer so that various data settings can be modified.

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Yokohama, Japan

Fumio Haruna