US 7,321,377 B2
Device and method for laser marking
Keisuke Endo, Shizuoka-ken (Japan); and Hiroyuki Nishida, Shizuoka-ken (Japan)
Assigned to FUJIFILM Corporation, Tokyo (Japan)
Filed on Apr. 26, 2004, as Appl. No. 10/831,349.
Claims priority of application No. 2003-123546 (JP), filed on Apr. 28, 2003; and application No. 2003-160366 (JP), filed on Jun. 05, 2003.
Prior Publication US 2004/0263604 A1, Dec. 30, 2004
Int. Cl. B41J 2/435 (2006.01)
U.S. Cl. 347—224 13 Claims
OG exemplary drawing
 
1. A method for laser marking in which a predetermined array of dots for forming a marking pattern are formed by irradiating a photosensitive material with a laser beam oscillated through a laser oscillation device, wherein
when a wavelength λ of the laser beam is within a range of equal to or larger than 9 μm and smaller than 10 μm, and a pulse width t for driving the laser oscillation device in order to form one dot is within a range of equal to or larger than 3 μsec and smaller than 30 μsec,
an energy density E (kw/cm2) of the laser beam on the photosensitive material and the pulse width t are set in an area defined by the following relations:
E=−10t+330, and
E=−15t+1000;
wherein said irradiating a photosensitive material deforms said photosensitive material to form dots having a convex surface; and
said dots comprise a plurality of small bubbles beneath the surface of the photosensitive material.