Mini-zoom projection lenses for use with pixelized panels
First Claim
1. A variable focus, mini-zoom projection lens for forming a magnified image of an object, said object having a height hO and said magnified image having a height hI, where |hI |>
- |hO |,said projection lens comprising;
(A) a first lens unit at the image end of the projection lens, said first lens unit comprising at least one lens element, the image end of said first lens unit being separated from the object by an axial distance D; and
(B) a second lens unit for zooming located between the first lens unit and the object, said second lens unit comprising at least one lens element, the image end of said second lens unit being separated from the object end of said first lens unit by an axial distance D12 ;
wherein;
(i) the object comprises a panel composed of pixels;
(ii) focusing of the projection lens comprises varying the axial distance D;
(iii) zooming of the projection lens comprises varying the axial distance D12 ;
(iv) the projection lens has a focus range F of at least 0.05, where F is defined by the formula;
space="preserve" listing-type="equation">F=max|h.sub.O /h.sub.I |-min|h.sub.O /h.sub.I |,where max |hO /hI | and min |hO /hI | are the maximum and minimum magnitudes, respectively, of the image-to-object magnification of the projection lens; and
(v) the projection lens has a zoom range Z whose maximum value ZMAX over the focus range is less than 0.15, where the zoom range Z is defined by the formula;
space="preserve" listing-type="equation">Z=2*(max|h.sub.I |-min|h.sub.I |)/(max|h.sub.I |+min|h.sub.I |),where max |hI | and min |hI | are the maximum and minimum magnitudes, respectively, of the image height as a result of zooming about a |hO /hI | ratio in the focus range.
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Abstract
Projection lenses for use with pixelized panels, e.g., LCD panels, are provided. The lenses have a large focus range, e.g., a focus range of greater than 0.05 and in many cases greater than 0.1, and a limited (mini) zoom range, e.g., a zoom range of less than 15% (±7.5% from the center of the range). By limiting the zoom range, complex lens structures involving large numbers of lens elements are avoided. In particular, the lenses employ at most one additional lens element and in many cases no additional lens elements compared to non-zooming lenses having a similar focus range.
77 Citations
16 Claims
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1. A variable focus, mini-zoom projection lens for forming a magnified image of an object, said object having a height hO and said magnified image having a height hI, where |hI |>
- |hO |,
said projection lens comprising; (A) a first lens unit at the image end of the projection lens, said first lens unit comprising at least one lens element, the image end of said first lens unit being separated from the object by an axial distance D; and (B) a second lens unit for zooming located between the first lens unit and the object, said second lens unit comprising at least one lens element, the image end of said second lens unit being separated from the object end of said first lens unit by an axial distance D12 ; wherein; (i) the object comprises a panel composed of pixels; (ii) focusing of the projection lens comprises varying the axial distance D; (iii) zooming of the projection lens comprises varying the axial distance D12 ; (iv) the projection lens has a focus range F of at least 0.05, where F is defined by the formula;
space="preserve" listing-type="equation">F=max|h.sub.O /h.sub.I |-min|h.sub.O /h.sub.I |,where max |hO /hI | and min |hO /hI | are the maximum and minimum magnitudes, respectively, of the image-to-object magnification of the projection lens; and (v) the projection lens has a zoom range Z whose maximum value ZMAX over the focus range is less than 0.15, where the zoom range Z is defined by the formula;
space="preserve" listing-type="equation">Z=2*(max|h.sub.I |-min|h.sub.I |)/(max|h.sub.I |+min|h.sub.I |),where max |hI | and min |hI | are the maximum and minimum magnitudes, respectively, of the image height as a result of zooming about a |hO /hI | ratio in the focus range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
- |hO |,
Specification