| 摘要 |
PURPOSE:To ease a design of a pattern applying an exposure method by an illuminating light, in which a light phase is periodically reversed, by making a number of light transmitting parts of a pattern group an odd number. CONSTITUTION:A pattern (grating) 2 is formed between electrode patterns 1 having a tandem type cross-finger state. In this case, (n) is decided with an integer of an even number selected out of a range of (n) in a formula I from a relation between a distance (1) and a line width (p), because the distance (1) and the line width (p) are decided by the characteristic of a piezoelectric substrate of an element, where p: both the pattern line widths of a pattern and a space of the pattern 2, n: a number of patterns, 1: a distance between two patterns 1, and d: a distance between the patterns 1 and 2. Then the distance (d) is determined by a formula II (provided p < d < 3p) to decide a pattern structure. |
