| 摘要 |
PURPOSE:To obtain a voice bobbin which has all properties required as a bobbin and is fitted to a diaphragm to produce a good acoustic transformer, by constituting the bobbin with carbon. CONSTITUTION:Outside and inside faces of a carbon including material which is substance 1 formed into a bobbin form and has carbon as main components are coated with boracic acid or silicon powder of diffusion materials 2 and 2'. This substance 1 is heated by a proper means, and diffusion materials 2 and 2' are permeated and diffused into substance 1 to form diffusion region 3 in substance 1. Thickness of coating layer 2 is controlled to achieve diffusion of coating layer 2 while considering a desired thickness of diffusion region 3 for thickness of substance 1. A bobbin obtained in this manner has properties such as a light weight, a large hardness, a heatproof property, a stability for humidity, a suitability for adhesive, etc. |
