Projection lens for mask pattern printing

Claim 2

A projection lens for mask pattern printing comprising a photographic lens arrangement which is interposed between an image plane and an object plane and used for both the alignment and the printing, and including at least one group of fixedly spaced lenses corrected for chromatic aberrations with respect to at least four wavelengths, and a pair of interchangeable lens elements which are interchangeably inserted into said arrangement at identical axial positions therein, one of said interchangeable lens elements being corrected for chromatic aberrations for at least two of said wavelengths and being designed for the alignment and inserted during alignment; the other of said interchangeable lens elements being corrected for chromatic aberrations for at least the other two wavelengths and being designed for the printing and inserted during printing; the axial spacing between said photographic lens arrangement and the image plane remaining the same during both alignment and printing, and the axial spacing between the object plane and the image plane remaining the same during both alignment and printing.

Claim 3

The projection lens according to claim 1, which is constructed of a lens arrangement of the substantially symmetric type.

Claim 4

A projection lens according to claim 2, in which the interchangeable lens elements, which are interchanged between the alignment operation and the printing operation, are inserted substantially at the center of the projection lens.

Claim 5

The projection lens according to claim 3, in which each interchangeable lens element inserted substantially at the center of the projection lens is a concave lens element.

Claim 6

A projection lens according to claim 1, wherein said fixedly spaced lenses include a pair of meniscus lenses having their concave surfaces facing toward each other, and convergent lens elements disposed axially outwardly of said meniscus lenses; each interchangeable lens element being a concave lens insertable between the two meniscus lenses.

Claim 7

A projection lens according to claim 5, wherein said interchangeable concave lenses are double concave cemented lenses.

Claim 8

A mask pattern printing projection lens, corrected for chromatic aberration with respect to at least three wavelengths, comprising a photographic lens arrangement which is interposed between an image plane and an object plane and used for both the alignment and the printing, and including at least one group of fixedly spaced lenses and a pair of interchangeable lens elements which are interchangeable inserted into said photographic lens arrangement at identical axial positions therein, one of said interchangeable lens elements being inserted into said photographic lens arrangement during alignment, and the other lens element being inserted into said photographic lens arrangement during printing; the photographic lens arrangement, with said one lens element inserted therein, being corrected for chromatic aberration with respect to two of said wavelengths and being designed for the alignment; the photographic lens arrangement, with said other lens element inserted therein, being corrected for chromatic aberration with respect to another two of said wavelengths and designed for printing; the axial spacing between said photographic lens arrangement and the image plane remaining the same during both alignment and printing, and the axial spacing between the object plane and the image plane remaining the same during both alignment and printing.

Claim 9

A mask pattern printing projection lens, corrected for chromatic aberration with respect to at least three wavelengths, comprising a photographic lens arrangement which is interposed between an image plane and an object plane and used for both the alignment and the printing, and including at least one group of fixedly spaced lenses and a pair of interchangeable lens elements which are interchangeable inserted into said photographic lens arrangement at identical axial positions therein, one of said interchangeable lens elements being inserted into said photographic lens arrangement during alignment, and the other lens element being inserted into said photographic lens arrangement during printing; the photographic lens arrangement, with said one lens element inserted therein, being corrected for chromatic aberration with respect to two of said wavelengths and being designed for the alignment; the photographic lens arrangement, with said other lens element inserted therein, being corrected for chromatic aberration with respect to another two of said wavelengths and designed for printing; the axial spacing between said photographic lens arrangement and the image plane remaining the same during both alignment and printing, and the axial spacing between the object plane and the image plane remaining the same during both alignment and printing.