Abstract: A multi-cylinder hydraulic shock absorber (D) expands and contracts in accordance with expansion and contraction of a working chamber (R1, R2) provided in a cylinder (1) and having a working fluid sealed therein. An outer periphery of the cylinder (1) is covered by an outer tube (4), and a gas chamber housing (10) projects upward from an upper end of the outer tube (4). A space between the outer tube (4) and the cylinder (1) and an inner side of the gas chamber housing (10) are used as a working fluid reservoir (5). A gas chamber (6) opposing a liquid level (S) of the working fluid is formed inside the gas chamber housing (10). With this constitution, a volume of the gas chamber (6) is secured when the multi-cylinder hydraulic shock absorber (D) is disposed horizontally while suppressing an increase in a diameter of the outer tube (4).

Abstract: A vehicle height adjusting device includes a cylinder (1), a rod (3) inserted in the cylinder (1), a piston (4) connected to the rod (3) and movable within the cylinder (1), and defining a rod side chamber (2a) and an non-rod side chamber (2b) in the cylinder (1), damping parts (4a, 4b) for generating a damping force by the movement of the rod (3), a high pressure chamber (18) and a low pressure chamber (16) charged with gas, a pump chamber (25) for adjusting the vehicle height by supplying the working fluid in the low pressure chamber (16) into the non-rod side chamber (2b), a communicating path (5a) for communicating the non-rod side chamber (2b) and the high pressure chamber (18), and a valve body (20) for increasing and reducing a channel area of the communicating path (5a) depending on the fluid pressure of the high pressure chamber (18).

Abstract: An optical unit includes a first lens, a second lens, a diaphragm, a third lens, a fourth lens, and a fifth lens, which are arranged in the stated order from an object side to an image plane side. The second lens has a convex shape. The third lens has a meniscus shape. The fourth lens has a convex shape. The fifth lens has a negative power.

Abstract: An optical unit includes a first lens, a diaphragm, a second lens, a third lens, a fourth lens, and a fifth lens. The first lens is a positive meniscus lens which is convex toward an object side. The second lens has a positive power. The third lens has a negative power. The fourth lens has a positive power. The fifth lens has a negative power. Those are arranged in the stated order from the object side to an image plane side.

Abstract: An optical unit includes: a first lens group; and a second lens group, which are arranged in order from an object side toward an image surface side, wherein the first lens group includes a first lens element, a first transparent body, and a second lens element, which are arranged in order from the object side toward the image surface side, and the second lens group includes a third lens element, a second transparent body and a fourth lens element, which are arranged in order from the object side toward the image surface side.

Abstract: An optical unit which includes (a) a first lens group; and (b) a second lens group, which are arranged in order from an object side toward an image surface side, the first lens group including (i) a first lens element, (ii) a first transparent body, and (iii) a second lens element, which are arranged in order from the object side toward the image surface side, and the second lens group including (i) a third lens element, (ii) a second transparent body and (iii) a fourth lens element, which are arranged in order from the object side toward the image surface side.

Abstract: A lens unit includes a front group, a stop, and a rear group, in order from the object side toward the image side. The front group includes at least: a first lens having a negative meniscus shape; a negative second lens formed from a plastic and having an aspherical surface; and a positive third lens, in order from the object side toward the image side. The rear group includes at least: a positive first lens; and a negative second lens, in order from the object side toward the image side.

Abstract: A gas chamber (G) and a liquid chamber (R) are separated by a free piston (2) in a cylinder (1) of a hydraulic damper. The free piston (2) comprises a hollow main body (3), a metal bellows (4) which elongates and contracts according to a pressure balance between the gas chamber (G) and liquid chamber (R), and a stopper (8) fixed to the main body (3) for preventing the metal bellows (4) from elongating beyond a predetermined length. By compensating for variation in the capacity of the liquid chamber (R) caused by a displacement of the piston (10) in the cylinder (1) by elongation or contraction of the metal bellows (4), the damping characteristic of the damper is prevented from becoming unstable due to a frictional force acting on the free piston (2). The stopper (8) prevents excessive stress from being exerted on the metal bellows (4).

Abstract: A vehicle height adjusting device includes a cylinder (1), a rod (3) inserted in the cylinder (1), a piston (4) connected to the rod (3) and movable within the cylinder (1), and defining a rod side chamber (2a) and an non-rod side chamber (2b) in the cylinder (1), damping parts (4a, 4b) for generating a damping force by the movement of the rod (3), a high pressure chamber (18) and a low pressure chamber (16) charged with gas, a pump chamber (25) for adjusting the vehicle height by supplying the working fluid in the low pressure chamber (16) into the non-rod side chamber (2b), a communicating path (5a) for communicating the non-rod side chamber (2b) and the high pressure chamber (18), and a valve body (20) for increasing and reducing a channel area of the communicating path (5a) depending on the fluid pressure of the high pressure chamber (18).

Abstract: A lens unit includes a front group, a stop, and a rear group, in order from the object side toward the image side. The front group includes at least: a first lens having a negative meniscus shape; a negative second lens formed from a plastic and having an aspherical surface; and a positive third lens, in order from the object side toward the image side. The rear group includes at least: a positive first lens; and a negative second lens, in order from the object side toward the image side.

Abstract: A gas chamber (G) and a liquid chamber (R) are separated by a free piston (2) in a cylinder (1) of a hydraulic damper. The free piston (2) comprises a hollow main body (3), a metal bellows (4) which elongates and contracts according to a pressure balance between the gas chamber (G) and liquid chamber (R), and a stopper (8) fixed to the main body (3) for preventing the metal bellows (4) from elongating beyond a predetermined length. By compensating for variation in the capacity of the liquid chamber (R) caused by a displacement of the piston (10) in the cylinder (1) by elongation or contraction of the metal bellows (4), the damping characteristic of the damper is prevented from becoming unstable due to a frictional force acting on the free piston (2). The stopper (8) prevents excessive stress from being exerted on the metal bellows (4).

Abstract: An optical disc drive compatible with optical discs of different types, for example, is provided. For focusing, through an optical system used in common with the different types of optical discs, a laser beam emitted from a selected one of a plurality of light sources disposed apart from each other radially of the optical disc, the optical system is moved radially of the optical disc correspondingly to the selection of the light source for emitting the laser light. Namely, it is possible to prevent the optical property from being deteriorated when a single optical pickup is used in common with such optical discs of different types.

Abstract: A hydraulic shock absorber with a self leveling function for a vehicle height is provided to prevent drop of a relief valve even if an excessive impulsive pressure is applied thereto. The relief valve is provided with a tubular valve case which is press-fitted into a press-fit bore of a partition wall member to divide an oil storage and a reservoir, and a valve body opening/closing a valve seat of an end portion of a flow passage formed in the partition wall member is urged toward the direction of the valve seat by a spring and is seated at the valve seat. This prevents an oil pressure in an oil chamber of the reservoir from acting directly on an end face of the valve case.

Abstract: A hydraulic shock absorber with a self leveling function for a vehicle height is provided to prevent drop of a relief valve even if an excessive impulsive pressure is applied thereto. The relief valve 100 is provided with a tubular valve case 101 which is press-fitted into a press-fit bore 112 of a partition wall member 111 to divide an oil storage 82 and a reservoir 81, and a valve body 104 opening/closing a valve seat 103 of an end portion of a flow passage 113 formed in the partition wall member 111 is urged toward the direction of the valve seat 103 by a spring 106 and is seated at the valve seat 103. This prevents an oil pressure in an oil chamber 86 of the reservoir 81 from acting directly on an end face of the valve case 101.

Abstract: The disclosed invention relates to an optical integrated device, an optical pickup, and an optical disk apparatus, and is applicable to an optical disk apparatus for playing back a compact disk (CD) and a DVD (Digital Video Disk), thereby to access a plurality of types of optical disks with a simple arrangement. For dividing feedback light with a hologram 19A and detecting the divided feedback light with a light-detecting element 20, laser sources 15A, 15B having different wavelengths are spaced a predetermined distance D from each other in order to compensate for the difference between the diffraction angles &thgr;A1, &thgr;B of the hologram 19A.

Abstract: An optical disc drive compatible with optical discs of different types, for example, is provided. For focusing, through an optical system used in common with the different types of optical discs, a laser beam emitted from a selected one of a plurality of light sources disposed apart from each other radially of the optical disc, the optical system is moved radially of the optical disc correspondingly to the selection of the light source for emitting the laser light. Namely, it is possible to prevent the optical property from being deteriorated when a single optical pickup is used in common with such optical discs of different types.

Abstract: An optical disc drive compatible with optical discs of different types, for example, is provided. For focusing, through an optical system used in common with the different types of optical discs, a laser beam emitted from a selected one of a plurality of light sources disposed apart from each other radially of the optical disc, the optical system is moved radially of the optical disc corresponding to the selection of the light source for emitting the laser light. Namely, it is possible to prevent the optical property from being deteriorated when a single optical pickup is used in common with such optical discs of different types.