Patent ID: 6754419
Filing Date: 2004-06-22
Classification: G02B

Abstract:
A discrete pattern, formed by dots discretely arranged in two dimensions, wherein said dots included in a rectangular area having a longitudinal length of Lx and a transverse length of Ly satisfy expression,D&lE;0.13Nâˆ’1.15â€ƒâ€ƒ(1) such that, N denotes the number of dots included in a predetermined area, and D is obtained by expression (2), wherein A(x,y) defines the number of dots, of a total of N dots, included in a rectangular area for which a line segment extended from reference coordinates (0,0) to an arbitrary coordinate point (x,y) is a diagonal line, D&af;(Lx,Ly;N)=&Integral;&Integral;Lx&it;xLyâ€ƒ&it;[A&af;(x,y)N-xyLx&it;Ly]2&it;&dd;x&it;&dd;yLx&it;Ly(2)and wherein S1 that is obtained by expression S1&af;(r1,r2)=&Integral;r1r2&it;&dd;r&it;&LeftBracketingBar;g1&af;(r;r1,r2)-gav&RightBracketingBar;(3)is equal to or smaller than 0.7, such that g1 is obtained by dividing the average radial distribution function g(r) of each dot in the area by an integration value of g(r) over a range of from r1 to r2, and gav is the average value of g1 within the range of from r1 to r2; such that, when the dots are arranged in a square lattice to satisfy a given filling rate, r1 and r2 are chosen as one and four times the value of the lattice constant &Dgr;r respectively; and the dot filling rate is a value obtained by multiplying the square of the maximum diameter of a dot by the number of dots, and dividing the product by the size of the area.