Photopolymerized media This type of plate is usually made of aluminum, photosensitive layer and surface layer. The photopolymerizable layer is mainly composed of a polymerized monomer (+ oligomer), an initiator, a spectral sensitizer and a film-forming resin. The initiator is widely used as a multi-initiator system with high quantum efficiency. The effect of the spectral sensitizer is to effectively extend the range of the initiator to the luminescence wavelength region of the laser. It can now extend to 488nm (ion laser) and 532nm ( Multiplied YAG laser). The role of the surface layer is mainly the atmosphere of oxygen molecules separated, to avoid its into the photosensitive layer, in order to improve the photosensitive layer of the chain growth efficiency, resulting in high sensitivity. As a result of these effective measures, the photopolymerization of the direct plate of the sensitivity has been greatly improved, the minimum imaging exposure has dropped to about 10μJ / cm2, second only to the silver salt type of direct plate, and this plate structure Simple, resolution, printing rate and post-processing and conventional PS version similar or even better. Since the range of intrinsic photoreactivity of most efficient initiator systems is in the ultraviolet region and the photometric range extends to the range of the emission wavelength of the UV-LD laser, the photopolymerized direct plate will become the next generation of UV direct Preferred system, has a very good development prospects.
