| 摘要 |
<p>PROBLEM TO BE SOLVED: To make the pitch of a projection pattern on an exposed surface the wavelength of a light source or below. SOLUTION: A laser beam 2 (wavelengthλ) emitted from the light source 1 is reflected by mirrors 3a and 3b, to be guided to a beam expander optical system 4. Further, the laser beam 2 is converged by a focusing lens 4a and passes through a pinhole 4c located in the focal plane of the focusing lens 4a, to be converted into a parallel luminous flux 5 whose beam diameter is expanded by a collimator lens 4b. Then, the parallel luminous flux 5 is made vertical incident on a phase shifter 6 constituted in such a manner that projecting and recessing parts are repeatedly formed on the light-emitting surface side of a parallel plate made of a transparent material having a refractive index of (n), to pass through the phase shifter 6. Consequently, +1st order diffracted light and -1st order diffracted light are obtained and interfere with each other on a photosensitive film facing the phase shifter 6 with a spacer 7, so that fine interference fringes are formed to expose the photosensitive film.</p> |
