Patent ID: 7233383
Filing Date: 2007-06-19
Classification: G03F

Abstract:
1. A maintenance method for a pattern generator that includes a pattern generating unit that includes plural pixels, and generates a predetermined pattern by driving the plural pixels, said maintenance method comprising the steps of: obtaining one or more of an optical performance of said pattern generating unit and a driving state of the plural pixels; and determining, based on information obtained by said obtaining step, whether the plural pixels deteriorate; and maintaining the pattern generating unit based on a determination by said determining step, wherein said determining step determines that the plural pixels deteriorate when a changing amount of the optical performance of the pixels is outside a permissible range, and further determines whether the cumulative deterioration times is equal to or greater than a predetermined value, and wherein said maintaining step exchanges the pattern generating unit when the cumulative deterioration time is equal to or greater than the predetermined value, and recovers the optical performance of the pixels when the cumulative driving time of the pixels is below the predetermined value.