Abstract: A projection type display device comprises a polarization splitting/color separating optical system for polarization-splitting and color-separating beam from an illumination optical system, reflection type light valves, each taking a rectangular shape, for modulating the beam from the polarization splitting color separating optical system in accordance with an image signal and letting the modulated beams exit, a color synthesizing optical system for color-synthesizing the beams from the reflection type light valves, a light analyzing optical system for analyzing the beam from the color synthesizing optical system, and a projection optical system for projecting on a predetermined surface an image based on the image signal generated in the reflection type light valves.

Abstract: A color synthesizing optical apparatus comprises a plurality of reflection type light valves, a color synthesizing/analyzing optical system, and quarter wave plates disposed corresponding to the plurality of light valves. In a state to effect image-displaying, in one of first and second light valve groups, phase advance axes of the quarter wave plates are disposed substantially in parallel to predetermined axes within surfaces of the light valves which axes correspond to the respective predetermined axes within the projection image field plane of the light valves. In the other group in the same state, phase advance axes of the quarter wave plates are disposed substantially perpendicularly to the predetermined axes within the surfaces of the light valves which axes correspond to the respective predetermined axes within the projection image field plane of the light valves.

Abstract: A color synthesizing optical apparatus comprises a plurality of reflection type light valves modulating incident light beams on the basis of image signals and letting the modulated light beams exit, a color synthesizing/analyzing optical system including polarization beam splitters corresponding to the plurality of reflection type light valves, and color-synthesizing and analyzing the light beams having exited the plurality of light valves, and quarter wave plates disposed corresponding to the plurality of light valves in light paths extending from exit surfaces of the light valves to incident surfaces of the polarization beam splitters.

Abstract: A projection type display device comprises a polarization splitting/color separating optical system for polarization-splitting and color-separating beam from an illumination optical system, reflection type light valves, each taking a rectangular shape, for modulating the beam from the polarization splitting/color separating optical system in accordance with an image signal and letting the modulated beams exit, a color synthesizing optical system for color-synthesizing the beams from the reflection type light valves, a light analyzing optical system for analyzing the beam from the color synthesizing optical system, and a projection optical system for projecting on a predetermined surface an image based on the image signal generated in the reflection type light valves.

Abstract: A method and apparatus for recording data on a magnetooptical recording medium finds an optimum laser beam intensities for recording. The method and apparatus do not cause a low level P.sub.L setting to become excessively low and poor overwriting of data during overwrite recording. Recording can be accomplished changing low level and high level laser beam intensities, while holding the ratio of the low level and high level laser beam intensities constant. Data can be reproduced and evaluated. When the optimum laser beam intensities have not been determined, the intensity ratio of the low level and high level intensities can be altered. After data has been is reproduced and evaluated, the process can be repeated, until the optimum laser beam intensities are obtained. Further, recording can be based on temperature of the recording medium and surroundings to obtain optimum laser beam intensities.

Abstract: The current invention is directed to an optical storage medium system and a method for adjusting an electrically converted optical signal representing the stored data based upon the environmental or optical disk temperature and/or a heat characteristics of the optical disk.

Abstract: A stabilized overwriteable optical recording method, wherein overwriting is performed sufficiently because erasure does not become poor with the low level laser beam intensity P.sub.L being set too low. In a method of setting the recording laser beam intensity by performing test recording on an overwriteable optical recording medium, the setting of the low level recording laser beam intensity and the setting of the high level recording laser beam intensity are respectively independently performed. According to a different embodiment of the invention, another stabilized overwriteable optical recording method is disclosed. After the signal of a predetermined pattern has been recorded on an overwriteable optical recording medium, the recorded predetermined pattern is played back, and by a comparison of the pattern recovered from its playback signal with the predetermined pattern, an appropriate recording laser beam intensity is found.

Abstract: A method of performing stabilized overwriteable optical recording, wherein overwriting is performed sufficiently even when erasure becomes poor when the low level laser beam intensity P.sub.L is set too low. The low level of recording laser beam intensity is set by playing back a test recording region by illuminating magnetization reversal areas after magnetization reversal areas have been formed in test regions of an overwriteable optical recording medium. Further, an erasure factor is found from the playback signal. In a second embodiment of a method of setting the recording laser beam intensity in order to perform recording on an overwriteable optical recording medium, before a test recording is performed, magnetization reversal areas are formed in a test recording region. These magnetization reversal areas are not erased, and a test recording is performed in this region by overwriting.

Abstract: A stabilized overwriteable optical recording method, wherein overwriting is performed sufficiently because erasure does not become poor with a low level laser beam intensity P.sub.L set too low. The method includes setting the recording laser beam intensity in order to perform recording on an overwriteable optical recording medium, finding the lower limit value of laser beam intensity at which a high temperature process occurs, and, based on this lower limit value of laser beam intensity, provisionally setting a high level laser beam intensity. After magnetization reversal marks have been formed in a test recording region by this lower limit value, the test recording region is played back. Then, after the test recording region has been illuminated with a laser beam, performing erasure of the magnetization reversal marks. Then the test recording region is played back, and by making a comparison of the playback signals before and after erasure was performed, the optimum low level laser beam intensity is set.

Abstract: A method and apparatus for recording data on a magnetooptical recording medium finds an optimum laser beam intensities for recording. The method and apparatus do not cause a low level P.sub.L setting to become excessively low and poor overwriting of data during overwrite recording. Recording can be accomplished changing low level and high level laser beam intensities, while holding the ratio of the low level and high level laser beam intensities constant. Data can be reproduced and evaluated. When the optimum laser beam intensities have not been determined, the intensity ratio of the low level and high level intensities can be altered. After data has been is reproduced and evaluated, the process can be repeated, until the optimum laser beam intensities are obtained. Further, recording can be based on temperature of the recording medium and surroundings to obtain optimum laser beam intensities.

Abstract: A data erasure device for an optical recording medium which controls the effects of a temperature rise of an optical recording medium during an erasure operation. The data erasure device irradiates a light beam on a recording medium, and erases data recorded on the medium by increasing the temperature of a portion of the recording medium irradiated by the light beam. The light beam is caused to blink between two states during the erasure operation to produce a uniform erasure mark.

Abstract: A control and method of overwrite optical recording with a first recording data transmission speed. In accordance with the method data which has been written, is verified for errors. When the number of errors exceeds a predetermined level, the data is re-recorded at the same location. The re-recording is either: 1) conducted with the same conditions; 2) conducted with a higher low level laser beam intensity; 3) conducted with the low level and high level laser beam intensities reversed; or 4) conducted after conducting a test recording and resetting the laser beam modulation intensity.

Abstract: A drive for an optical information recording medium comprises a medium holder for holding the optical information recording medium, a drive mechanism for driving the medium, a movable optical head for radiating a light beam to the medium, a body having the drive mechanism and the optical head built therein, a cooling air inlet port formed in the body, and a fan provided in the body for venting the interior of the body. A sealed box having a medium insertion port with a door is provided in the body. The box accommodates no heat generating component and accommodates at least the medium holder and the optical head.

Abstract: A drive for an optical information recording medium comprises a medium holder for holding the optical information recording medium, a drive mechanism for driving the medium, a movable optical head for radiating a light beam to the medium, a body having the drive mechanism and the optical head built therein, a cooling air inlet port formed in the body, and a fan provided in the body for venting the interior of the body. A sealed box having a medium insertion port with a door is provided in the body. The box accommodates no heat generating component and accommodates at least the medium holder and the optical head.