| 摘要 |
PROBLEM TO BE SOLVED: To illuminate an object to be inspected with uniform brightness by a method wherein a permeating light quantity control means is operated by means of a light quantity uniformizing means to uniformize an illumination quantity distribution from a light source for the object to be inspected. SOLUTION: A liquid crystal filter 5 in STN mode is provided between a light source 4 and a semiconductor package 1 which is an object to be inspected and an amount of permeating light forwarding toward the semiconductor package 1 is controlled corresponding to a permeating position. A filter controller 6 is electrically connected to the liquid crystal filter 5 and a dot control section 6a individually controls torsion angles of the liquid crystal, then the dot control section 6a operates in accordance with a dot density edited in a dot density editing section 6b which is a personal computer so that a prescribed gray level is applied to the liquid crystal filter 5. As a result, a permeating quantity of the light from the light source 4 at the liquid filter 5 is controlled by means of the filter controller 6. |
