Other

Mitsubishi Electric Corporation

Nkk Corporation

Hiroyoshi Takeuchi

Hiroyoshi Suenaga

Kuninori Minakawa

Hideaki Fukai

Takeshi Ito

Akira Tanabe

Yoji Tsutsumishita

Toshio Sakiyama

Masakuni Takagi

A voltage supply apparatus includes: a primary cell; and a constant voltage supply unit. The constant voltage supply unit has set therein a voltage drop determination value, which is a threshold that is higher than a positional-data loss level and is lower than a second output voltage, which is a constant voltage at a steady voltage level that the constant voltage supply unit outputs when in a steady state. The constant voltage supply unit converts a first output voltage of the primary cell to the second output voltage and supplies it to the absolute-position detection apparatus until the first output voltage falls below the threshold. When the first output voltage falls below the threshold, the constant voltage supply unit converts the first output voltage to a third output voltage which is a voltage at the same level as the threshold, and supplies it to the absolute-position detection apparatus.

Voltage supply apparatus

A method for lapping two surfaces of a titanium disk comprises inserting loosely a titanium disk to be lapped into an opening in a disk-type carrier, the carrier rotating and revolving between an upper surface plate and a lower surface plate which are held in parallel with each other and which applies lapping pressure to the titanium disk, feeding abrasives between the surface plates and the titanium disk and satisfying the following relationship between thickness t (mm) of the titanium disk and thickness T (mm) of the carrier:

Method for lapping two surfaces of a titanium disk

According to a mirror surface polishing process of the present invention, it is possible to produce Ti-made magnetic disc substrate which have the excellent flatness degree and surface roughness in that the average roughness is not more than 0.05 .mu.m and the flatness degree of the outer periphery is not more than 0.15 .mu.m.

Method for mirror polishing of ti-made magnetic disk substrate

Growing community of inventors

Tokyo, Japan

Hiroyoshi Takeuchi