Abstract: A projection image display device 1 includes a housing 100, a projection lens 110, a front convex portion 50A and a rear convex portion 50B. The housing 100 accommodates an illumination optical system and a modulation optical system in an interior thereof. The projection lens 110 is configured to project an image modulated by the modulation optical system in a scaled-up size, and is disposed on a first lateral face 100b of the housing 100. The front convex portion 50A and the rear convex portion 50B are disposed on an intersection line between a plane containing an optical axis of the projection lens 110 and a top face 110a of the housing 100.

Abstract: An image projection device includes a replaceable air filter placed near an opening of a housing, a switcher for switching step by step a working area of the air filter, an air-speed meter for detecting a pollution level of the air filter, and a controller for controlling the switcher. When the air-speed meter detects that the pollution level of the air filter reaches a given threshold, the controller prompts the switcher to switch the working area of the air filter, and then detects a pollution level of the air filter after the switchover for determining whether or not the working area before the switchover needs to be switched.

Abstract: The present invention provides a shutter apparatus and a drive method for the same, the shutter apparatus having functions of both a shutter apparatus for an image interception and a shutter apparatus for an aperture adjustment and being space-saving and low in costs. Within an illumination casing are provided first and second shading plates 212 and 215, first and second cammed gear 224 and 227 having a cam groove 225 and 228 respectively for driving the first shading plate 212 and the second shading plate 215 respectively. A cam shape is structured such that the rotation of a DC motor 235 (one drive source) enables the first and second shading plates 212 and 215 to drive independently. Thus, arbitrarily operating the functions of both the shutter apparatus for the image interception and the shutter apparatus for the aperture adjustment by the DC motor 235 (one shared drive source) is possible.

Abstract: An image projection device includes a replaceable air filter placed near an opening of a housing, a switcher for switching step by step a working area of the air filter, an air-speed meter for detecting a pollution level of the air filter, and a controller for controlling the switcher. When the air-speed meter detects that the pollution level of the air filter reaches a given threshold, the controller prompts the switcher to switch the working area of the air filter, and then detects a pollution level of the air filter after the switchover for determining whether or not the working area before the switchover needs to be switched.

Abstract: The present invention provides a shutter apparatus and a drive method for the same, the shutter apparatus having functions of both a shutter apparatus for an image interception and a shutter apparatus for an aperture adjustment and being space-saving and low in costs. Within an illumination casing are provided first and second shading plates 212 and 215, first and second cammed gear 224 and 227 having a cam groove 225 and 228 respectively for driving the first shading plate 212 and the second shading plate 215 respectively. A cam shape is structured such that the rotation of a DC motor 235 (one drive source) enables the first and second shading plates 212 and 215 to drive independently. Thus, arbitrarily operating the functions of both the shutter apparatus for the image interception and the shutter apparatus for the aperture adjustment by the DC motor 235 (one shared drive source) is possible.

Abstract: A multibeam antenna for simultaneously receiving waves from one or more communication satellites and a broadcast satellite, which are apart in their stationary orbit positions over the equator, is disclosed. The antenna employs an offset parabolic face, used as a reflector for receiving satellite broadcast waves, a converter having a primary radiator for receiving communication satellite Waves set at the focus point of the offset parabolic face, and a converter having a primary radiator for receiving broadcast satellite waves set near the envelope of the broadcast waves reflected from the offset parabolic face. The offset parabolic face is pointed in the direction of the communication satellite such that the plane of symmetry of the offset parabolic face is coincident with a plane specified by the communication satellite, the broadcast satellite, and the receiving point of the antenna.