PURPOSE: To obtain a light-weight and high-rigidity diaphragm which is suited to the flat plate type speaker, by forming the core component of the pulp material featuring a small mass and with projections arranged regularly and then forming the core material by adhering such core components to each other along with the skin material adhered to both sides of the core material.
CONSTITUTION: Core component 1 contains quadrangular pyramid type projections 1a arrranged regularly, and the area is flat valley 1b between projections 1a. Such components 1 and 1 are made to oppose to each other to be adhered together at valley part 1b, thus forming core material 2 possessing hollow space 1c. Then skin material 3 made of the metals like aluminum, berylium and the like or the thin plate of the mica, carbon plate or the like is adhered to both sides of material 2. Thus diaphragm 10 is obtained. In such constitution, the diaphragm features a small mass to secure the light weight, and furthermore a high rigidity and proper internal loss can be obtained according to the structure.
KAWAHARA FUMIO
SANBE TOSHIAKI
MOGAMI DENKI