Optical disc having substrates with a specified thickness/diameter ratio and an adhesive layer with a specified Young's modulus range and mechanical dissipation factor range

摘要

An optical disc is constructed by joining a pair of resin substrates through an adhesive layer so that information carrying means is disposed inside. The resin substrate has a diameter-to-thickness ratio d/t≧ 180. The adhesive layer has a Young's modulus of 0.1-1 kgf/mm.sup. 2 at 20. degree. C. and a mechanical dissipation factor (tan. delta.) of 0.6-5.0 at 20° C. The adhesive layer is formed of a hot melt adhesive, pressure-sensitive adhesive, room temperature curable adhesive or ultraviolet curable adhesive. The disc is resistant to both heat and vibration.