Method for adjusting of a measuring device by an adjustment body, adjustment body and method for adjusting an adjustment body

A method for adjusting a measuring device (20) comprising an interferometer (22) having a first interferometer defining an optical axis (A) and having an object lens (25), a optical distance measuring device (30) having a measuring axis (M) and a support slide (32) arranged between the interferometer (22) and the optical distance measuring device (30) that is movable along a slide axis (S), the method comprising:

• aligning the measuring axis (M) parallel to the slide axis (S),
• positioning a workpiece (21) in a position in which the focus of the object lens (25) is located on a surface of the workpiece (21),
• emitting a spherical wavefront (Ws) by the interferometer (22) on the workpiece (21),
• receiving a spherical return wavefront (Wr) reflected by the workpiece (21),
• creating an interference pattern by using the spherical return wavefront (Wr) in the interferometer (22),
• inclining the object lens (25) relative to the optical axis (A) until the interference pattern indicates that the object lens (25) is oriented at a right angle to the optical axis (A),
• removing the workpiece (21) and providing an adjustment body (40) arranged at the support slide (32) having a front side (43) and a back side (44) opposite to the front side (43), wherein the front side (43) is facing the interferometer (22) and the back side (44) is facing the optical distance measuring device (30), wherein at least one spherical reflection and/or a diffraction surface (54, 55) is present at the front side (43) and a retro reflector (42) defining a vertex (47) is present at the back side (44), wherein a center point line (G) extends through a center point (P1, P2) of the at least one spherical reflection and/or diffraction surface (54, 55) and the vertex (47),
• emitting another spherical wavefront (Ws) by the interferometer (22) onto the at least one spherical reflection and/or diffraction surface (54, 55),
• receiving a spherical return wavefront (Wr) reflected by the at least one spherical reflection and/or diffraction surface (54, 55),
• creating an interference pattern in the interferometer (22) by using the spherical return wavefront (Wr),
• creating a relative movement between the adjustment body (40) and the object lens (25) of the interferometer (22) in a confocal position (K1, K2) in which the interference pattern indicates that a normal of the spherical reflection and/or diffraction surface (54, 55) and a normal of the spherical wavefront (Ws) impinging at this location are parallel,
• wherein the adjustment body (40) comprises a first spherical reflection and/or diffraction surface (54) and a second spherical reflection and/or diffraction surface (55) with different radii (r1, r2) at the front side, the center points (P1, P2) of which are located on the common center point line (G).