Abstract: A compact rear projection image display apparatus in which the projection distance in a projection optical system is substantially reduced and no reflection mirror is used, thereby eliminating a major cause of image trapezoidal distortion. The rear projection image display apparatus has a projection lens system which includes a first lens group with positive refractive power and a second lens group which further enlarges an image enlarged by the first lens group. The projection lens system enlarges and projects an image displayed on an image display device, on a transmission screen. No reflection mirror is provided between the second lens group and the transmission screen and the image enlarged by the second lens group is directly projected on the transmission screen.

Abstract: The present invention relates to a rear projection type image display device comprising projection lenses (2, 3) for projecting an image displayed on an image display element onto a transmission type screen (6) on a larger scale, an optical path turn-back mirror (7) for turning back halfway a light beam projected from the projection lenses, and a drive circuit for displaying an image on the image display element, that are fixedly housed within a housing (5). When a diagonal size of the transmission type screen (6), the depth of the housing (5), and the length from a lower end of the screen (6) to a lower end of the housing (5), are assumed to be SS (inch), D (inch), and L (inch), respectively, the following conditions are satisfied: SS>40, D?SS/3.0, L?SS/10.

Abstract: An inexpensive projection lens unit in a rear projection type image display system, having a short focal distance (wide angle of viewing field), high focus and high contrast, and as well, including a power lens made of a glass material having a high refractive index in a range from 1.63 to 1.70 and an Abbe's number of not less than 50 with an optimized incident and emergent configuration in order to satisfactorily correct aberration with a enhanced focusing performance even with a shortened focal distance. Further, the power lens having a high refractive index can exhibit a high power, and accordingly, can carry out satisfactory aberration correction by optimizing the aspheric degree of a plastic lens even though the length of back focus is increased for enhancing the contrast.

Abstract: In a projection type image display apparatus, a projector optical unit for projecting an image onto a screen while magnifying a size of the image to be projected with respect to an original size of the image displayed by an image forming element, has a group of lenses for magnifying the size of the image with respect to the original size thereof, and an optical path extending from the image forming element to the screen to transmit the image along the optical path.

Abstract: In a projection lens, there are arranged in order from a screen side, a first lens group including a meniscus lens having a convex lens surface in a central portion toward a screen with refracting power, a second lens group including a lens having a convex lens surface in a central portion toward a video generating source, a third lens group including a lens having convex lens surfaces in both sides with positive refracting power, a fourth lens group including a lens having a convex lens surface in a central portion toward the video generating source with positive refracting power, and a fifth lens group including a lens having a concave lens surface toward the screen with negative refracting power. An entrance pupil is arranged between incident and emitting surfaces of a power lens.

Abstract: In a projection lens, there are arranged in order from a screen side, a first lens group including a meniscus lens having a convex lens surface in a central portion toward a screen with refracting power, a second lens group including a lens having a convex lens surface in a central portion toward a video generating source, a third lens group including a lens having convex lens surfaces in both sides with positive refracting power, a fourth lens group including a lens having a convex lens surface in a central portion toward the video generating source with positive refracting power, and a fifth lens group including a lens having a concave lens surface toward the screen with negative refracting power. An entrance pupil is arranged between incident and emitting surfaces of a power lens.

Abstract: To avoid that IGBTs are destroyed by receiving overvoltages while an overcurrent flows through series-connected IGBTs of a semiconductor power converting apparatus, a gate driver for controlling a gate voltage of the MOS control semiconductor owns a power supply line having a higher potential than such a gate potential when the MOS control semiconductor is brought into a steady ON state, and when a potential difference between the power supply line and an emitter of the MOS control semiconductor is constant, and also a collector voltage of the MOS control semiconductor exceeds a predetermined value under ON state of the MOS control semiconductor, the power source line of the gate driver supplies a current from the power source line to the gate of the MOS control semiconductor so as to increase the gate voltage of the MOS control semiconductor.

Abstract: A compact receptacle for mating connection with a complementary coaxial plug connector. The receptacle is in use to be mounted on a mobile phone for switching a signal line from an internal antenna to a vehicle's external antenna when placed on a cradle in a vehicle in mating connection with the plug connector on the cradle. The receptacle has a dielectric mold carrying an outer conductor shield fitted on top of the mold, a single spring member, and a single fixed contact member. The conductor shield includes an electrode socket for connection with an outer conductor tube of the plug. The spring member integrally carries a center electrode for connection with a center conductor post of the plug, and a movable contact which forms a normally-closed switch with a fixed contact on the fixed contact member for the above signal switching.

Abstract: A compact receptacle for mating connection with a complementary coaxial plug connector. The receptacle is in use to be mounted on a mobile phone for switching a signal line from an internal antenna to a vehicle's external antenna when placed on a cradle in a vehicle in mating connection with the plug connector on the cradle. The receptacle has a dielectric mold carrying an outer conductor shield fitted on top of the mold, a single spring member, and a single fixed contact member. The conductor shield includes an electrode socket for connection with an outer conductor tube of the plug. The spring member integrally carries a center electrode for connection with a center conductor post of the plug, and a movable contact which forms a normally-closed switch with a fixed contact on the fixed contact member for the above signal switching.