Pioneer Electronic Corporation

Kunihiko Shimada

Yukio Tsuchiya

Satoru Tanaka

Shuichi Yanagisawa

Isao Yamamuro

A recordable optical disk is provided with: a disk substrate having a recording surface; a track portion, which is coaxially or spirally arranged on the recording surface, and to which the information is recorded by irradiating a light beam modulated in correspondence with the information, thereonto; and an interval portion disposed on the recording surface between adjacent turns of the track portion on the recording surface. The reflection coefficient of the interval portion is higher than the reflection coefficient of the track portion.

Optical disk, method of manufacturing the same and method of recording

A plurality of delay circuits each having a different delay time are inserted between an audio signal source and each speaker in a multiple-speaker system so that the frequency dependence of speaker system directivity is reduced. If desired, the audio signal can be divided into different frequency band signals with each frequency band signal subjected to a different delay or set of delays.

Loudspeaker system

A coaxial type planar diaphragm loudspeaker system in which a plurality of coaxially arranged polygonal diaphragms are provided with separate magnetic circuits. Each magnetic circuit includes two parallel plate along each side of the diaphragm with a voice coil bobbin having the same shape as the corresponding polygonal diaphragm coupled thereto with a voice coil attached to the opposite end and disposed in the gap formed in the magnetic circuit. The area of the diaphragm falling within the juncture line between the voice coil bobbin and diaphragm is made equal to the area of the diaphragm outside the juncture line so as to eliminate split vibration.

Coaxial type multi-way planar diaphragm loudspeaker system

A magnetic circuit for a planar diaphragm type loudspeaker having a square planar diaphragm and square voice coil in which four magnetic circuits are arranged in a square corresponding to the edges of the planar diaphragm. Pairs of plates are disposed opposite to one another upon which are attached a number of magnets with the opposed poles opposite one another along the inner walls of the oppositely disposed plates. Each of the magnets is rectangular in shape. A yoke connects the pairs of plates. Holes for permitting air flow are formed either in the yoke or in the pairs of oppositely disposed plates in patterns such as to not disturb the magnetic field. The magnetic circuit units made up by the magnets, pairs of plates, and yokes are joined at their ends by magnetic couplings. An electrical conductive member may be disposed over portions of the magnets to prevent the occurrence of third harmonic distortion due to current distribution.

Magnetic circuit for planar diaphragm type loudspeaker

A coaxial multi-way planar diaphragm loudspeaker system having inner and outer frames rigidly coupled to each other. An inner peripheral edge portion of a planar diaphragm for the bass-range and an outer peripheral edge portion of a planar diaphragm for the mid-range are commonly supported by a common edge supporting member which is rigidly coupled to the front surface of the inner frame. A single backchamber is provided for the mid-range and higher-range speaker units to separate them from the rear chamber of the bass-range loudspeaker unit. The backchamber has an inclined surface portion extending toward the the rear-side of the bass-range loudspeaker unit. The driver units for the treble-ranges are attached to the frame through a mounting bracket having an oblong screw hole so that they can first be assembled then accurately positioned.

Coaxial multi-way planar diaphragm type loudspeaker system

A driver unit for a square planar diaphragm type loudspeaker system in which a voice coil bobbin attached to the square planar diaphragm is supported by a corrugated damper the other end of which is attached to a heat conducting support whereby heat generated within the voice coil of the speaker can be readily dissipated. A square magnetic circuit is provided including a plurality of straight magnetic circuit sections positioned along corresponding sides of the square planar diaphragms. Each of these straight magnetic circuit sections includes a pair of parallel plate members along inner walls of which opposite plurality magnets are disposed and with a yoke connecting the opposite ends of the plate members. The voice coil which is attached to the voice coil bobbin is disposed in the air gap between oppositely disposed magnets. The damper support is mounted on the outer plate member with a flange portion extending over the upper edge of the outer plate member and having an upper flange portion to the upper surface of which the damper is attached. The damper is formed of a corrugated section of treated cloth which has no elasticity in its longitudinal direction but which is free to move in a direction perpendicular to the plane of the diaphragm.

Driver unit for planar diaphragm type loudspeaker

A voice coil bobbin construction for a planar diaphragm loudspeaker including plural bobbin frames joined together to form the composite voice coil bobbin. In one embodiment, the bobbin frames each have a coupling member at each end thereof which are bonded together in a planar contact. Reinforcing ribs may be provided extending parallel to the planar diaphragm. In another embodiment, a mounting flange intimately bonded to the planar diaphragm and a voice coil flange upon which the voice coil is mounted are provided. A damper fastening portion can also be formed by leaving a portion free of through-holes in the bobbin frames. The feeder wires to the voice coil can be run through the through-holes in the bobbin frames.

Growing community of inventors

Tokorozawa, Japan

Kunihiko Shimada