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Compact projection lenses for use with large format pixelized panels

  • US 7,009,777 B2
  • Filed: 06/02/2004
  • Issued: 03/07/2006
  • Est. Priority Date: 06/02/2004
  • Status: Expired due to Fees
First Claim
Patent Images

1. A projection lens for forming an enlarged image of a pixelized panel on a screen, said projection 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 consisting in order from the long conjugate side to the short conjugate side of;

    (A) a first lens sub-unit having a negative power and comprising a negative lens element which (i) has a short conjugate surface which is concave towards the short conjugate side and (ii) comprises at least one aspheric surface; and

    (B) a second lens sub-unit;

    (II) an aperture stop; and

    (III) a second lens unit having a positive power, an effective focal length fU2, and consisting in order from the long conjugate side to the short conjugate side of;

    (A) a first lens sub-unit having a positive power, an effective focal length fU2S1 and comprising a positive lens element and a negative lens element, the positive lens element having a lower dispersion than the negative lens element; and

    (B) a second lens sub-unit which, in order from the long conjugate side to the short conjugate side, comprises;

    a negative lens element having a focal length fneg and a lens element which comprises an aspherical surface which has a positive on-axis power;

    ora lens element having first and second optical surfaces,—

    where the first surface has a negative power θ

    neg, the second surface is an aspherical surface which has a positive on-axis power, and the first and second surfaces are separated by an axial distance t which satisfies the relationship;


    t/f0

    0.05;

    wherein;

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

    (b) fU2/f0

    1.5;

    (c) fU2S1/f0

    2.0; and

    (d) |fneg|≦

    2.0·

    f0 or 1/|θ

    neg|≦

    1.5·

    f0.

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