| 摘要 |
PROBLEM TO BE SOLVED: To provide a gap measuring apparatus that can receive, without using any mask, light from a specific point in an extending gap.SOLUTION: A gap measuring apparatus 1 has a light source 5 that irradiates a gap 3 to be measured, a lens optical system 6 that causes a gap image 3A of light transmitted by the gap 3 to be formed on an image formation face 7, and a light receiving element 9 that receives the gap image 3A formed on the image formation face 7 of the lens optical system 6. Over the image formation face 7, a holed mask 8 having a hole 8a of a prescribed bore for letting light pass is disposed, and the light receiving element 9 receives the gap image 3A via the hole 8a. An image of an extending gap is caused to be formed by the lens optical system 6 and the hole 8a of the holed mask 8 is placed over the point to be measured on the image formation face 7 of the lens optical system 6, so that the gap dimensions of the point to be measured in the gap 3 can be measured. |
