摘要 |
<p>An injection compression molding method for compact discs or the like, comprising the step of changing the clamping pressure or compression pressure, after the internal cavity pressure in the mold after injection has reached its peak, stepwise or continuously as the cooling proceeds, thereby making the applied pressure per unit area with respect to the effective pressure range constant. In a compact disc formed by this method, the residual stress after cooling is uniform, so that its optical properties are improved substantially.</p> |