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Color-corrected projection lenses for use with pixelized panels

  • US 7,002,753 B2
  • Filed: 06/02/2004
  • Issued: 02/21/2006
  • Est. Priority Date: 06/02/2004
  • Status: Expired due to Fees
First Claim
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1. A retrofocus lens having a long conjugate side, a short conjugate side, and an effective focal length f0, said lens, in order from the long conjugate side to the short conjugate side, comprising:

  • (I) a first lens unit having a negative power, said lens unit, in order from the long conjugate side to the short conjugate side, comprising;

    (A) a first lens element L1 composed of an optical material having an Abbe number vL1, said element having at least one aspherical surface and an on-axis optical power φ

    L1; and

    (B) a second lens element L2 composed of an optical material having an Abbe number vL2, said element having at least one aspherical surface and an on-axis optical power φ

    L2; and

    (II) a second lens unit having a positive power;

    wherein;

    (a) the first and second lens units are the only lens units of the retrofocus lens;

    (b) the first lens element L1 has a generally meniscus shape which is convex towards the long conjugate;

    (c) the second lens element L2 has a biconcave shape when its surface configurations are described by best fit spherical curves;

    (d) φ

    L1, vL1, φ

    L2, and vL2 satisfy the relationships;

    (i) φ

    L1<

    0;

    (ii) |φ

    L1|>



    L2|;

    (iii) vL2<

    vL1; and

    (iv) vL2

    55; and

    (e) the at least one aspherical surface of the second lens element L2 is configured so that the element has an optical power φ

    L2/0.7CA at 0.7 of the clear aperture of its short conjugate surface which satisfies the relationships;

    φ

    L2/0.7CA<

    0, and|φ

    L2/0.7CA|>



    L2|.

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