| 摘要 |
PURPOSE:To attain the accurate control for the position of a writing spot by using a control signal only when the laser output light is not recorded after converting said output light into the record light and non-record light. CONSTITUTION:A position controller controls the position of a writing spot 6 in response to the output characteristics C of a laser 1. The input to be supplied to the position controller is selectively switched. The laser output light B is converted into the record light B1 having high light intensity when a record signal A delivered from a record signal generator is set under a state A1. Then the record element is formed at an information medium 5. This reflected light 7 is made incident to a photodetecting element 9 in an unstable state, and the control signal given from the element 9 is not supplied to the position controller. When a record signal A is set at A2, the light B is turned into the non-record light B2. The reflected light 7 of the light B2 is stable and therefore a stable control signal is obtained and supplied to the position controller. Thus the position of the spot 6 is controlled with high accuracy. |
