Novel exposure system using light-emitting diodes and an optical fiber array for printing code marks

Abstract

The feasibility of a novel economical and environmentally friendly exposure system using a light-emitting diode (LED) array as a light source was demonstrated. Such an exposure system is especially useful for printing two-dimensional code marks for the production management of semiconductor devices and liquid crystal display panels. The new system also uses an optical fiber matrix array connected to the LED array. The tips of the plastic optical fibers of 1 mm diameter are heated and deformed into a square shape, and the square fiber ends are projected by a 1/10 reduction lens. Using LEDs with a central wavelength of 405 nm and an output power of 40 mW/cm 2 , quasi-square code mark patterns are printed with good size repeatability in a practically feasible short time of less than 2 s.

Investigations of Matrix-Exposure Lithography Using Stacked Linear Arrays of Squared Optical Fibers

“…Matrix-exposure lithography using a plastic optical fiber matrix with squared ends was proposed in our past research earlier than 2010 [1][2][3][4]. Each fiber in the matrix was led individually to a light emitting diode (LED) for supplying exposure light.…”

Readability dependence on lithography conditions for printing code marks using a squared optical fiber matrix and light-emitting diodes

“…For this reason, a new exposure method using an LED matrix as an exposure source was proposed in past research. [12][13][14] In addition, optical fibers with squared ends were developed for improving the shapes of mark cells, 15) and the optical fibers were bound in a matrix. 16) Because bright and dark codemark cells with a square shape are directly assigned by simply lighting and extinguishing LEDs, this combination of LED and fiber matrices is very effective for printing arbitrary code marks easily but precisely.…”