Pioneer Corporation

Other

Tohoku Pioneer Corporation

Tohoku Corporation

Hiroyuki Tomiyama

Satoshi Hachiya

Masatoshi Sato

Koji Takayama

Yasuhisa Abe

Koji Matsumoto

Yoshimi Kudo

Yuichi Kasahara

Kouichi Honma

A substrate () made by a thin magnesium plate having a thickness of at most 60 &#x3bc;m and bent in a predetermined shape is subjected to anodic oxidation using an alkali-mixture aqueous solution containing metallic salt with a pH 12 or more so that porous anodic oxide coatings () are formed on the surfaces thereof. A first treated substrate () having the anodic oxide coatings () is immersed in a bath of a dye (B), which fills the pores (A) of the anodic oxide coatings () and dyes the substrate, providing a second treated substrate (). The second treated substrate () is subjected to electrodeposition using electrodeposition paint made mainly of acrylic resin, forming electrodeposition coatings () on the anodic oxide coatings (). A magnesium diaphragm is thereby produced, which is thin and has sufficient sensitivity and desired characteristics. The diaphragm thus dyed has metallic gloss and hence acquires a high decorative value.

Magnesium diaphragm, method of manufacturing the same, and speaker apparatus

In a rolling process, the level of rolling performed by a rolling mill for one operation is set to 1 &#x3bc;m to 20 &#x3bc;m. A magnesium substrate is rolled by rollers while being heated by a thermostatic chamber. As a result, there is manufactured a high-quality magnesium sheet which is less susceptible to influence of oxidation, which realizes a high internal loss, prevention of a drop in sensitivity, and low distortion, and which has a thickness of 30 &#x3bc;m to 100 &#x3bc;m. Further, as a result of the magnesium sheet being formed into a semi-dome shape or a dome shape, the sheet can be inexpensively manufactured as a speaker for high-tone playback. In particular, in the case of a magnesium diaphragm into which a dome section and an edge section are integrally formed, high-quality sound can be played back in a high frequency range without involvement of a drop in sensitivity.

Method of manufacturing a magnesium diaphragm

A butterfly damper for supporting a voice coil bobbin of a speaker on a frame in a state that the damper is vibrative. The butterfly damper is made of olefinic resin material having an internal loss of 0.045 or greater, a tensile elongation of 200% or greater, and a flexural modulus of 300 MPa or greater.

Speaker damper

There is provided an electrically conductive damper device for a speaker in which local bending is reduced and break-downs of material of the damper and metallic wires incorporated in the damper are prevented, by additionally providing one or more sheets of damper fabric as a reinforcing damper and by bonding it to a main damper by way of various kinds of resin, in order to reinforce a neck portion of the electrically conductive damper. Further, properties of the damper can be adjusted by varying an outer diameter of the reinforcing damper , or by selecting the resin to be employed as an adhesive.

Electrically conductive damper device for speaker

A damper for a speaker includes an auxiliary damper impregnated with a thermosetting resin, a laminate film laminated on the auxiliary damper , and a primary damper formed on the auxiliary damper or the laminate film . Alternatively, the damper may include the auxiliary damper impregnated with the thermosetting resin (phenol) and coated with a coating agent, and the primary damper formed on the auxiliary damper and the coating agent . Thus, the dual damper which has enhanced reliability in resisting a high power and can be produced at a low cost without variation in the production can be obtained.

Growing community of inventors

Yamagata, Japan

Hiroyuki Tomiyama