MANUFACTURE OF SPATIAL OPTICAL MODULATING ELEMENT

PROBLEM TO BE SOLVED: To prevent irregularity in the thickness of an optical modulating layer by forming fine projections on the depression surface of a depression surface plate so that the peak parts of the fine projections are in a same level. SOLUTION: The depression surface plate 6 is rectangular and has the fine projections 6a formed on one rectangular surface so that the peak parts of the fine projections 6a are in the same plane M. Namely, the side of the fine projections 6a is mounted on thin plate glass and this depression surface plate 6 presses the thin plate glass across the fine projections 6a. Then the thin plate glass is adhered to a glass substrate where a hologram color filter is formed. Further, a transparent electrode and an alignment film are formed by a vacuum vapor-depositing method on the opposite side of the thin plate glass from the glass substrate side. Further, the thin plate glass is pressed with a uniform load by the depression surface plate 6 having the peak parts in the same plane M, so none of recessed parts corresponding to an air bubble and dust is formed.