| 摘要 |
The present invention relates to a high resolution exposure apparatus for a plate printing machine using near-infrared ray, which comprises a plurality of laser diodes which emits lights with wavelengths of 800-860 nm; optical fibers which wave guide the lights emitted from each laser diode; and a lens unit which focuses the lights emitted through the optical fibers into a target printing image surface. The lens unit includes first through eighth lenses in order from the optical fiber to the image surface. The first lens has convex spherical surfaces on both sides and has a positive refractive power. The second lens has concave spherical surfaces on both sides and has a negative refractive power. The third lens has a meniscus type positive refractive power which has a convex image surface. The fourth lens has a meniscus type negative refractive power which has a concave image surface. The fifth lens has the positive refractive power in which both sides are convex. The sixth lens has the positive refractive power in which both sides are concave. The seventh lens has the negative refractive power in which both sides are concave. The eighth lens has a convex surface which faces with the seventh lens and has the positive refractive power. The fourth and fifth lenses are mutually welded, and the sixth and seventh lenses are mutually welded. According to the high resolution exposure apparatus for lithography printer using near-infrared ray, numerical aperture can be greater, a light focusing rate can be enhanced, and high resolution can be provided. |
