Zoom projection lens systems
First Claim
1. A zoom projection lens system for use with a predetermined illumination means, said system forming a well-corrected, real image of an object and having an optical axis, an entrance pupil, a physical aperture stop which defines the system'"'"'s numerical aperture, and an operative aperture stop whose location is defined by the intersection with the optical axis of a ray from the illumination means aimed at the center of the entrance pupil, said system comprising:
- (a) at least two lens units each comprising at least one lens element, said at least two lens units being separated by at least one axial space; and
(b) zoom means for varying the system'"'"'s magnification between a maximum and a minimum magnification by changing the at least one axial space;
wherein as the zoom means varies the system'"'"'s magnification between the maximum and minimum magnifications;
(i) the entrance pupil remains at a substantially fixed position relative to the illumination means over the zoom range;
(ii) the operative aperture stop moves through at least one lens element surface; and
(iii) the physical aperture stop and the operative aperture stop are at different locations for at least one magnification between said maximum and minimum magnifications.
4 Assignments
0 Petitions
Accused Products
Abstract
Zoom projection lens systems are provided which have 1) an entrance pupil which remains at a substantially fixed position as zooming takes place, and 2) a operative aperture stop, distinct from the system'"'"'s physical aperture stop, which moves through lens surfaces as zooming takes place. The fixed entrance pupil allows for efficient coupling to a light source throughout the magnification range of the system. Methods which can be used to design and produce zoom lens systems of this type and which employ a pseudo-aperture stop are also disclosed.
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Citations
36 Claims
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1. A zoom projection lens system for use with a predetermined illumination means, said system forming a well-corrected, real image of an object and having an optical axis, an entrance pupil, a physical aperture stop which defines the system'"'"'s numerical aperture, and an operative aperture stop whose location is defined by the intersection with the optical axis of a ray from the illumination means aimed at the center of the entrance pupil, said system comprising:
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(a) at least two lens units each comprising at least one lens element, said at least two lens units being separated by at least one axial space; and (b) zoom means for varying the system'"'"'s magnification between a maximum and a minimum magnification by changing the at least one axial space; wherein as the zoom means varies the system'"'"'s magnification between the maximum and minimum magnifications; (i) the entrance pupil remains at a substantially fixed position relative to the illumination means over the zoom range; (ii) the operative aperture stop moves through at least one lens element surface; and (iii) the physical aperture stop and the operative aperture stop are at different locations for at least one magnification between said maximum and minimum magnifications. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 35, 36)
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2. A zoom projection lens system for use with a predetermined illumination means, said system forming a well-corrected, real image of an object and having an entrance pupil, said system comprising:
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(a) at least two lens units each comprising at least one lens element, said at least two lens units being separated by at least one axial space and including a lens unit nearest the image which has a lens element nearest the image; and (b) zoom means for varying the system'"'"'s effective focal length between a maximum and a minimum value by changing the at least one axial space; wherein the system has a Q-value greater than about 1.0, where the Q-value is defined by;
space="preserve" listing-type="equation">Q=(EFL.sub.max *θ
)/(CA*f/no*L)and where EFLmax is the maximum value of the system'"'"'s effective focal length, θ
is the semi-angular coverage in degrees at the system'"'"'s minimum effective focal length, CA is the clear aperture of the lens element nearest the image, f/no is the distance from the object to the system'"'"'s entrance pupil divided by the diameter of the entrance pupil for entrance pupils located a finite distance from the object and f/no is one over two times the numerical aperture determined by the illumination means for entrance pupils located an infinite distance from the object, and L is the number of lens elements in the system which have optical power or correct aberrations. - View Dependent Claims (3)
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17. A method for producing a zoom projection lens system for use with illumination means which produces an output at a predetermined location, said system producing a well-corrected, real image of an object and having an optical axis and an entrance pupil, said method comprising:
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(a) designing the zoom projection lens system by; (1) specifying at least two lens units which are separated by at least one axial space and which each comprise at least one lens element, said at least one axial space being variable so as to change the system'"'"'s magnification between a maximum and a minimum magnification; (2) specifying the location of the system'"'"'s entrance pupil to be substantially the same as the location of the output of the illumination means over the system'"'"'s zoom range; and (3) not specifying the location of the system'"'"'s physical aperture stop which defines the system'"'"'s numerical aperture; whereby the system has an operative aperture stop whose location is defined by the intersection with the optical axis of a ray from the illumination means aimed at the center of the entrance pupil, said location moving through at least one lens surface as the system'"'"'s magnification varies between the maximum and minimum magnifications; and (b) producing the zoom projection lens system designed in step (a). - View Dependent Claims (18, 19, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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20. A method for producing a zoom projection lens system for use with illumination means which produces an output at a predetermined location, said system producing a well-corrected, real image of an object and having an optical axis and a entrance pupil, said method comprising:
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(a) designing the zoom projection lens system by; (1) specifying at least two lens units which are separated by at least one axial space and which each comprise at least one lens element, said at least one axial space being variable so as to change the system'"'"'s magnification between a maximum and a minimum magnification; and (2) specifying the location of the system'"'"'s entrance pupil to be substantially the same as the location of the output of the illumination means over the system'"'"'s zoom range by specifying the location of a pseudo-aperture stop which is in the system'"'"'s object or image space and has the same location as the output of the illumination means; whereby the system has an operative aperture stop whose location is defined by the intersection with the optical axis of a ray from the illumination means aimed at the center of the entrance pupil, said location moving through at least one lens surface as the system'"'"'s magnification varies between the maximum and minimum magnifications; and (b) producing the zoom projection lens system designed in step (a). - View Dependent Claims (21)
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Specification