PURPOSE: To reduce processes in number and to increase the mechanical strength of a line part by patterning a light-absorptive projection dark part lines on the external surface of a transparent substrate and passing only a light beam within a specific angle.

CONSTITUTION: Some or all of processes of a photoetching and a photoforming method are used to fix projection parts made of light absorbing materials on one or both surfaces of the transparent substrate 2, thereby patterning the dark part lines required to limit a visual field. The effective thickness of a filter part 1 for light beam control is so determined under relative conditions among the thickness of the substrate 2, the width of a space part, the width of the line parts, and the found visual field angle that an incident light beam which is larger than the visual field angle is absorbed and cut off. Further, remaining resist 4 is used as an individual layer or a laminate where a metallic layer 3 is fixed as it is to constitute the line parts, thereby improving the operation efficiency.