Moulding tool for moulding a ceramic green body and use of said moulding tool

1) Moulding tool for moulding a ceramic green body in the production of at least one rotationally symmetrical lens consisting of an opto-ceramic, wherein at least one surface to be moulded can be described by the following equation

• y
• =
• c
• 
• 
• x
• 2
• 1
• +
• 1
• -
• (
• k
• +
• 1
• )
• 
• c
• 2
• 
• x
• 2
• +
• a
• 1
• 
• x
• 2
• +
• a
• 2
• 
• x
• 4
• +
• a
• 3
• 
• x
• 6
• +
• a
• 4
• 
• x
• 8
• +
• …
• (
• Equation
• 
• 
• A
• )
• wherein the constants have the following values:
• k is in the range of from −200 to +200, preferably between about −50 to +50, particularly preferably between about −10 to +10, more particularly preferred between about −2 to +2,
• c=1/R and is about <1*10−2 mm−1, preferably about <1*10−3 mm−1, particularly preferred about <4*10−6 mm−1, more particularly preferred about <1*10−6 mm−1, wherein R is the radius of the curve,
• the coefficients a1,2,3,4 . . . are about <10−1, preferably about <10−2, particularly preferred about <10−3,
• wherein the moulding tool comprises a near-net-shape negative mould of the functional area of the at least one area to be moulded of the at least one lens, that can be described as follows
• y
• 
• 
• 1
• =
• c
• 
• (
• 
• x
• 
• +
• b
• )
• 2
• 1
• +
• 1
• -
• (
• k
• +
• 1
• )
• 
• c
• 2
• 
• (
• 
• x
• 
• +
• b
• )
• 2
• +
• a
• 1
• 
• (
• 
• x
• 
• +
• b
• )
• 2
• +
• a
• 2
• 
• (
• 
• x
• 
• +
• b
• )
• 4
• +
• a
• 3
• 
• (
• 
• x
• 
• +
• b
• )
• 6
• +
• a
• 4
• 
• (
• 
• x
• 
• +
• b
• )
• 8
• +
• …
• (
• Equation
• 
• 
• B
• )
• wherein b is a constant above zero with preferred values being smaller than 0.3 mm, smaller than 0.1 mm, and most preferred smaller than 0.05 mm;
• b and describes the deviation of the negative mould of the moulding tool from the at least one area to be moulded of the at least one lens.