| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a laser marking method which facilitates quantitative estimation of visibility, maintains original enhancement of the image quality of a photosensitive material and to enhances the visibility of a dot pattern. <P>SOLUTION: A region where fine bubbles 16B are formed can be enlarged by making a dot pattern 16A convex, and since a plurality of fine bubbles 16B are formed, irregular reflection of light is promoted at a boundary film between the bubbles 16B, and the inside and outside of the dot pattern 16A can be made markedly different from each other in reflectance. The visibility of the dot pattern 16A is therefore enhanced independently of the density distribution of an X-ray film 12. In order to dispose a plurality of fine bubbles 16B in the convex dot pattern 16A, laser beam irradiation time is adjusted to 6 to 15 μs when the oscillation wavelength of a laser oscillator 44 is in a 9 μm band. When a post-development state is taken into consideration, the laser beam irradiation time is preferably 6 to 10 μs. <P>COPYRIGHT: (C)2004,JPO |
