| 摘要 |
PURPOSE:To prevent information from being easily forged and falsified by recording the information by forming a mirror part and a non-mirror part on the surface of a metallic layer without lowering practically the total reflec tion factor of the whole surface of this metallic layer. CONSTITUTION:The information is recorded by forming the mirror part 3 to reflect normally reading light 5 and the non-mirror part 4 to reflect abnormally the reading light 5 on the surface of a metal vapor deposited layer 2 formed on one side of an optional base member 1 without lowering practically the total reflection factor of this layer 2. When the reading light 5 from a projector 7 irradiates the irregular reflection part 4 and the mirror part 3 formed on a mirror surface in this way, the quantity of reflected light 6 incident to a light receiving device 8 is very small at the mirror part 3, and the quantity of the reflected light 6 is considerably large at the irregular reflection surface 4. The recorded information can be read out by making the difference of these reflected lights 6, 6' a signal. Through this method, since a metallic master disk is very difficult to produce, forgery is impossible. |
