Prism, method of producing a prism, and optical head apparatus using a prism

1. A method of producing a prism comprising a first prism component and a second prism component that are joined together along a partial reflection plane that is inclined with respect to the optical axis wherein said method has steps comprising:

measuring the refractive index of three or more multiple base materials which are used as said first prism component and said second prism component to obtain respective values of the refractive index of three or more base materials; and

joining the three or more of said base materials together along partial reflection planes to construct a laminated body with said three or more base materials according to the values of said refractive index so that the values of said refractive index are arranged in an incremental or decremental manner; and then

cutting said laminated body to obtain the prism comprising the first prism component and the second prism component, thereby producing a plurality of prisms.

2. The method of producing a prism according to claim 1 , further comprising:

cutting a large starting base material capable of producing a first prism component and a second prism component to obtain the three or more base materials.

3. The method of producing a prism according to claim 1 , wherein when three or more of said base materials are joined together along the partial reflection planes, the three or more of said base materials are joined in which a difference between the values of said refractive index of two adjacent base materials satisfies the following inequality:

−0.001<Δn<0.001

Where Δn is the difference between the values of said refractive index.