U.S. patent application number 10/658212 was filed with the patent office on 2005-03-10 for dual-band lens.
Invention is credited to Lawson, John, Ter Louw, Jan David.
Application Number | 20050052755 10/658212 |
Document ID | / |
Family ID | 34226738 |
Filed Date | 2005-03-10 |
United States Patent
Application |
20050052755 |
Kind Code |
A1 |
Lawson, John ; et
al. |
March 10, 2005 |
DUAL-BAND LENS
Abstract
A single lens or optical system is used to image two different
optical bands, for example visible and infrared, with the same
possible adjustments in zoom and/or focus. A dual band singlet is
formed of a first, larger, optical element, suitable for operating
on light of a first optical band, with an aperture cut out of it. A
smaller element, suitable for operating on light of a second
optical band, is secured in, or on either side of, the aperture cut
through the larger optical element, thus forming a dual band
singlet that can operate on two different wavelength bands.
Combinations of dual band lenses, lens elements, and lenses with
cut-out apertures are used to form dual-band optical systems,
including systems with dual-band focus and zoom.
Inventors: |
Lawson, John; (Sahaurita,
AZ) ; Ter Louw, Jan David; (Franklin Lakes,
NJ) |
Correspondence
Address: |
Mark A Lundgren
pmb #218
2621 Green River Rd.
Ste. #105
Corona
CA
92880
US
|
Family ID: |
34226738 |
Appl. No.: |
10/658212 |
Filed: |
September 9, 2003 |
Current U.S.
Class: |
359/722 |
Current CPC
Class: |
G02B 13/146 20130101;
G02B 3/10 20130101; G02B 15/00 20130101 |
Class at
Publication: |
359/722 |
International
Class: |
G02B 003/00; G02B
013/00 |
Claims
1-8. (Cancelled)
9. A dual optical system, comprising: a first optical subsystem,
comprising a first plurality of lenses, wherein, a portion of the
first plurality of lenses comprise cut-out sub-apertures and
remaining apertures; and a second optical subsystem, comprising a
second plurality of lenses; wherein, a portion of the second set of
lenses are positioned within the cut-out sub-apertures of the first
set of lenses, wherein, the first optical subsystem transmits a
first band of optical wavelengths through the remaining apertures,
and the second optical subsystem transmits a second band of optical
wavelengths not transmitted by the first optical subsystem.
10. The dual optical system of claim 9, wherein the first optical
subsystem and the second optical subsystem are refractive.
11. The dual optical system of claim 10, wherein the first set of
lenses, the second set of lenses, and the sub-apertures are
circular.
12. The dual optical system of claim 11, wherein a portion of the
first set of lenses and a portion of the second set of lenses are
disposed along a common optical axis.
13. The dual optical system of claim 12, wherein the first optical
subsystem is capable of producing a first image and the second
optical subsystem is capable of producing a second image.
14. The dual optical system of claim 13, wherein the first optical
subsystem comprises a first subsystem focus group, the second
optical subsystem comprises a second subsystem focus group, and
wherein the dual optical system further comprises a first focus
mechanism, attached to and capable of moving the first and second
sub-system focus groups.
15. The dual optical system of claim 14, wherein the first band of
optical wavelengths is an infrared band, and the second band of
optical wavelengths is a visible band.
16. The dual optical system of claim 10, wherein the first optical
system comprises a first subsystem focus group, the second optical
subsystem comprises a second subsystem focus group, and the dual
optical system further comprises a first focus mechanism, attached
to and capable of moving the first and second sub-system focus
groups.
17. The dual optical system of claim 16, wherein the first band of
optical wavelengths is an infrared band, and the second band of
optical wavelengths is a visible band.
18. The dual optical system of claim 9, further comprising: a focus
element, the focus element comprising: a first lens, capable of
refracting light of a first band of optical wavelengths, and having
an aperture cut through it; and a second lens, capable of
refracting light of a second band of optical wavelengths, fixed in
the aperture of the first lens; and a focus mechanism, attached to
the focus element, capable of moving the focus element.
19. The dual optical system of claim 18, wherein the first optical
subsystem is capable of producing a first image formed of light
from the first optical wavelength band, and the second optical
subsystem is capable of producing a second image from light of the
second optical wavelength band, and wherein motion of the focus
element adjusts the focus of both the first image and second
image.
20. The dual optical system of claim 19, wherein the optical system
is receptive of light along a common light path, and further
comprising: a first output light path; a second output light path;
and a fold element, capable of directing a portion of light of the
first optical band along a first output light path, and wherein
light of the second optical band exits along a second output light
path.
21. The dual optical system of claim 20, wherein the first band of
optical wavelengths is an infrared band, and the second band of
optical wavelengths is a visible band.
22. The dual optical system of claim 20, further comprising: a
first recording means, for recording the first image positioned in
the first output path; and a second recording means, for recording
the second image positioned in the second output path.
23. The dual optical system of claim 22, further comprising display
means, for displaying the first image and/or the second image to an
operator.
24. (Currently amended) The dual optical system of claim 23,
wherein the first band of optical wavelengths is an infrared band,
and the second band of optical wavelengths is a visible band.
25. A dual optical system, comprising: a first optical subsystem,
comprising a first set of lenses, wherein, a portion of the first
set of lenses comprise cut-out sub-apertures; and a second optical
subsystem, comprising a second set of lenses; wherein, a portion of
the second set of lenses are positioned within the sub-apertures of
the first set of lenses, wherein the first optical subsystem
further comprises a first variator group and a first compensator
group, and wherein the second optical subsystem further comprises a
second variator group in contact with the first variator group and
a second compensator group in contact with the first compensator
group, and wherein the dual optical system further comprises a zoom
mechanism, capable of moving the first and second variator groups
and the first and second compensator groups.
26-27. (Cancelled)
28. A dual band optical system, comprising: a first imaging means,
receptive of light of a first wavelength band, for forming a first
image, and having a first annular aperture; a second imaging means,
receptive of light of a second wavelength band, for forming a
second image, and having a second aperture, wherein the second
aperture is contained within the first aperture; and a focusing
means, for adjusting focus of the first image and the second image,
simultaneously.
29. A dual band lens, having a visible optical path and an infrared
optical path, comprising: a dual-band focus group, comprising an
annular first infrared lens element having an inner radius, and a
circular first visible lens element, located within the inner
radius of the annular infrared lens element; a fixed infrared
imaging group, comprising a plurality of fixed infrared lens
elements; and a fixed visible imaging group, comprising a plurality
of fixed visible lens elements; wherein, the dual band focus group
and the fixed infrared imaging group are placed along the infrared
optical path, and wherein the dual and focus group and the fixed
visible imaging group are placed along the visible optical
path.
30. The dual band lens of claim 29, wherein a portion of the
plurality of fixed infrared lens elements comprise cut-out
sub-apertures, and wherein a portion of the visible optical path
passes through the cut out sub-apertures.
31. A dual band lens, having a visible optical path and an infrared
optical path, comprising: a dual-band focus group, comprising an
annular first infrared lens element having an inner radius, and a
circular first visible lens element, located within the inner
radius of the annular infrared lens element: a fixed infrared
imaging group, comprising a plurality of fixed infrared lens
elements: and a fixed visible imaging group, comprising a plurality
of fixed visible lens elements: wherein, the dual band focus group
and the fixed infrared imaging group are placed along the infrared
optical path, and wherein the dual and focus group and the fixed
visible imaging group are placed alone the visible optical path,
wherein a portion of the plurality of fixed infrared lens elements
comprise cut-out sub-apertures, and wherein a portion of the
visible optical path passes through the cut out sub-apertures,
further comprising: a dual-band variator group, comprising an
infrared variator element positioned along the infrared optical
path and a visible variator element positioned along the visible
optical path, in contact with the infrared variator element; a
dual-band compensator group, comprising an infrared compenstator
element positioned along the infrared optical path and a visible
compensator element positioned along the visible optical path, in
contact with the infrared compensator element; and a zoom
mechanism, in contact with the dual band variator group and the
dual band compensator group, capable of zooming the dual band
lens.
32. The dual lens of claim 31, wherein, the dual-band focus group
first infrared lens element has a first radius of curvature of
approximately 73 mm, a second radius of curvature of approximately
2847 mm, a thickness of approximately 6 mm, a diameter of
approximately 52 mm, and is formed of AMTIR4; the dual-band focus
group first visible lens element is a cemented doublet, having a
first radius of curvature of approximately 0.95 inches, a second
radius of approximately 0.49 inches a first thickness of
approximately 10.04 inches of F2, a second thickness of
approximately 0.2 inches of BK7, and a diameter of approximately
0.63 inches; the infrared variator element has a first radius of
curvature of approximately -46 mm, a second radius of approximately
53 mm, a thickness of approximately 2.4 mm, a diameter of
approximately 30 mm and is formed of AMTIR4; the visible variator
element is a cemented doublet, having a first radius of curvature
of approximately -0.73 inches, a second radius of approximately
0.04 inches a first thickness of approximately 0.06 inches of SF6,
a second thickness of approximately 0.04 inches of LAKN12, and a
diameter of approximately 0.47 inches; the infrared compensator
element has a first radius of curvature of approximately 46 mm, a
second radius of approximately 214 mm, a thickness of approximately
4 mm, a diameter of approximately 42 mm, and is formed of AMTIR4;
the visible compensator element is a cemented doublet, having a
first radius of curvature of approximately 0.98 inches, a second
radius of approximately 0.34 inches a first thickness of
approximately 0.04 inches of LAF2, a second thickness of
approximately 0.06 inches of SK4, and a diameter of approximately
0.39 inches; the plurality of fixed infrared lens elements
comprises: a first lens, having a first radius of curvature of
approximately 51 mm, a second radius of approximately 669 mm, a
thickness of approximately 4 mm, a diameter of approximately 37 mm,
formed of AMTIR4; and a second lens, having a first radius of
curvature of approximately infinity, a second radius of
approximately infinity, a thickness of approximately 1 mm, a
diameter of approximately 12 mm, formed of GE_LONG; and, the
plurality of fixed visible lens elements comprises: a first lens,
having a first radius of curvature of approximately 1.68 inches, a
second radius of approximately 0.59 inches, a thickness of
approximately 0.08 inches, a diameter of approximately 0.47 inches,
formed of SF57; and a second lens, having a first radius of
curvature of approximately 0.72 inches, a second radius of
approximately -0.7 inches, a thickness of approximately 0.16
inches, a diameter of approximately 0.47 inches, formed of
LAKN12.
33. The dual lens of claim 25, wherein, the dual-band focus group
first infrared lens element has a first radius of curvature of
approximately 73 mm, a second radius of curvature of approximately
2847 mm, a thickness of approximately 6 mm, a diameter of
approximately 52 mm, and is formed of AMTIR4; the dual-band focus
group first visible lens element is a cemented doublet, having a
first radius of curvature of approximately 0.95 inches, a second
radius of approximately 0.49 inches a first thickness of
approximately 10.04 inches of F2, a second thickness of
approximately 0.2 inches of BK7, and a diameter of approximately
0.63 inches; the infrared variator element has a first radius of
curvature of approximately -46 mm, a second radius of approximately
53 mm, a thickness of approximately 2.4 mm, a diameter of
approximately 30 mm and is formed of AMTIR4; the visible variator
element is a cemented doublet, having a first radius of curvature
of approximately -0.73 inches, a second radius of approximately
0.04 inches a first thickness of approximately 0.06 inches of SF6,
a second thickness of approximately 0.04 inches of LAKN12, and a
diameter of approximately 0.47 inches; the infrared compensator
element has a first radius of curvature of approximately 46 mm, a
second radius of approximately 214 mm, a thickness of approximately
4 mm, a diameter of approximately 42 mm, and is formed of AMTIR4;
the visible compensator element is a cemented doublet, having a
first radius of curvature of approximately 0.98 inches, a second
radius of approximately 0.34 inches a first thickness of
approximately 0.04 inches of LAF2, a second thickness of
approximately 0.16 inches of SK4, and a diameter of approximately
0.39 inches; the plurality of fixed infrared lens elements
comprises: a first lens, having a first radius of curvature of
approximately 51 mm, a second radius of approximately 669 mm, a
thickness of approximately 4 mm, a diameter of approximately 37 mm
formed of AMTIR4; and a second lens, having a first radius of
curvature of approximately infinity, a second radius of
approximately infinity, a thickness of approximately 1 mm, a
diameter of approximately 12 mm, formed of GE_LONG; the plurality
of fixed visible lens elements comprises: a first lens, having a
first radius of curvature of approximately 1.68 inches, a second
radius of approximately 0.59 inches, a thickness of approximately
0.08 inches, a diameter of approximately 0.47 inches, formed of
SF57; and a second lens, having a first radius of curvature of
approximately 0.72 inches, a second radius of approximately -0.7
inches, a thickness of approximately 0.16 inches, a diameter of
approximately 0.47 inches, formed of LAKN12.
34. The dual optical system of claim 21, wherein, the first lens of
the focus element has a first radius of curvature of approximately
63 mm, a second radius of curvature of approximately 750 mm, a
thickness of approximately 6 mm, a diameter of approximately 51 mm,
and is formed of AMTIR4; the second lens of the focus group, has a
first radius of curvature of approximately 37 mm, a second radius
of approximately 389 mm a thickness of approximately 1.4, a
diameter of approximately 12mm, and is formed of F2; the first set
of lenses comprises: a first infrared imaging lens, having a first
radius of curvature of approximately -49 mm, a second radius of
approximately -86 mm, a thickness of approximately 4.5 mm, a
diameter of approximately 42 mm, formed of AMTIR4; and a second
infrared imaging lens, having a first radius of curvature of
approximately 22 mm, a second radius of approximately 23 mm, a
thickness of approximately 5 mm, a diameter of approximately 22 mm,
formed of AMTIR4; and, a third infrared imaging lens, having a
first radius of curvature of approximately infinity, a second
radius of approximately infinity, a thickness of approximately 1
mm, a diameter of approximately 12mm, formed of GE_LONG; the second
set of lenses comprises: a first visible imaging lens, having a
first radius of curvature of approximately 37 mm, a second radius
of approximately 389 mm inches, a thickness of approximately 0.7
mm, a diameter of approximately 9 mm, formed of FK5; a second
visible imaging lens, having a first radius of curvature of
approximately 0.72 inches, a second radius of approximately -0.7
inches, a thickness of approximately 0.16 inches, a diameter of
approximately 0.47 inches, formed of LAKN12; a third visible
imaging lens, being a cemented doublet, having a first radius of
curvature of approximately -933 mm, a second radius of
approximately -8.6 mm, a first thickness of approximately 3.4 m of
SK5, a second thickness of approximately 3.4 mm of SF11, and a
diameter of approximately 12mm; and, a fourth visible imaging lens,
having a first radius of curvature of approximately 47 mm, a second
radius of approximately -22 mm, a thickness of approximately 3 mm,
a diameter of approximately 12mm, formed of BK7.
Description
FIELD OF THE INVENTION
[0001] 1. Field
[0002] Embodiments relate to the field of optics and in particular
to imaging lenses.
[0003] 2. Related Art
[0004] Different cameras, sensitive to different optical wavelength
bands, are commercially available for a variety of applications.
For example, visible cameras and infrared cameras are used in
industrial, security, and rescue applications. Infrared and
Ultraviolet cameras are used in fire detection. It can be
advantageous to have two different cameras, sensitive to two
different wavelength bands, observe the same scene. For example, a
visible camera could be combined with an infrared camera. The
visible camera would show a typical image of a scene, so that an
operator could see normally. Meanwhile, the infrared camera would
show the operator where there were hot-spots.
[0005] One approach to providing dual waveband viewing is to mount
two separate cameras on a common base. Another approach is to use a
shared reflective optical system, because reflective systems can
typically process light of many different wavelengths. After
passing through the reflective system, the light from each band is
separated and directed to its own imaging device. However, there
are problems with both approaches.
[0006] When two separate cameras are mounted on a common base, they
do not view objects along the same optical axis. Therefore, there
is parallax between the two cameras; objects don't line up
identically in the two cameras at all field distances. An exception
is the case where there is a common aperture, and a beam-splitter
is used to direct light of each wavelength band to each camera.
However, as aperture increases, a larger and larger beam-splitter
is required. As beam-splitter size increases, so does cost and
difficulty of manufacture.
[0007] Further, if the two cameras have adjustable focus or zoom,
matching focus or zoom changes between the two separate systems can
be difficult. Typical zoom or focus settings on cameras are not
precisely metered or calibrated. Therefore, it is likely that the
two cameras might focus at different object distances or have
different magnification (different image size for the same object).
This could make it difficult to recombine the images on a single
display, or perform data fusion or other image processing. Two
separate systems also have more mass and take up more space than a
single camera.
[0008] When a reflective lens is used, multiple wavelengths can be
imaged simultaneously through the same reflective optics. However,
reflective systems are difficult to focus by element motion,
typically take up more space than refractive systems, and are
difficult to design with zoom features.
[0009] Therefore, what is needed is a refractive lens system which
can image scenes in two differing wavelength bands, through the
same aperture, and which can provide focus and zoom capability for
both wavelength bands with the same adjustments.
SUMMARY OF THE INVENTION
[0010] Embodiments include a lens formed of two lens elements: a
smaller lens element fixed within an aperture cut through a larger
lens element. In some embodiments, a lens is formed of an infrared
lens element and a visible lens element. Embodiments include
optical systems that contain dual wavelength lenses, so that a
single optical system can image the same scene in two different
optical wavelength bands through the same aperture. Embodiments
include systems with common zoom and focus groups, capable of
imaging in dual wavelength bands (for example visible and infrared,
visible and UV, UV and infrared, two infrared bands)
simultaneously.
BRIEF DESCRIPTION OF THE ILLUSTRATIONS
[0011] FIG. 1A and FIG. 1B are plan and axial views of a single
dual-band lens, according to the present invention.
[0012] FIG. 2 is a plan view of a complex dual-band lens, according
to the present invention.
[0013] FIG. 3 is a plan view of a dual band lens with a focus
group, according to the present invention.
[0014] FIG. 4A is a plan view of a dual band zoom lens, according
to the present invention.
[0015] FIG. 4B-FIG. 4I are diagrams that illustrate the motions of
infrared and visible subsystems in a dual band lens, according to
the present invention.
[0016] FIG. 5 is a plan view of a dual wavelength camera, according
to the present invention.
DESCRIPTION
[0017] FIG. 1A and FIG. 1B are plan and axial views of a single
dual-band lens, according to the present invention. The dual bands
may be any optical bands (e.g., near-infrared, mid-infrared,
long-infrared, very-long-infrared, visible, ultraviolet). Dual-band
lens 110 is formed of first lens element 120, which is constructed
of a refractive optical material. In some embodiments, for example,
where infrared light is to be imaged, lens element 120 is formed of
a suitable infrared lens material (e.g., Ge, Si, ZnSe, CaF2) that
transmits and refracts infrared light. In some embodiments, lens
element 120 is formed of a suitable visible lens material (e.g.,
BK7, F2) that transmits and refracts visible light, or another
wavelength-appropriate material, depending on the wavelength band
for which imaging is to be performed.
[0018] Lens element 120 is formed with sub-aperture 122 cut out.
Sub-aperture 122 may be formed during casting of the lens, drilled
out of the substrate, or any other process. In some embodiments,
sub-aperture 122 is circular and concentric with lens element 120.
In some embodiments, undesired light is excluded by coating 123 on
lens element 120, by the spectral transmittance properties of the
material of which lens element 120 is formed, or other means, such
as a filter placed in front of lens element 120.
[0019] Wavelengths of light for which lens element 120 is designed,
travel along paths represented by ray path 124, through
aperture-portion 125. The light is refracted (focused) by lens
element 120 and proceeds along ray path 126 to focus point 128,
which may be an image.
[0020] Lens element 130 is shown fixed in sub-aperture 122.
However, lens element 130 could also be disposed on either side of
sub-aperture 122. Lens element 130 is formed of a refractive
optical material, appropriate for a second optical wavelength band.
Undesired wavelengths of light can be excluded by appropriate
wavelength-selective coating 133, the material of lens element 130,
a filter earlier in the optical path, or any other method.
[0021] Light suitable to refraction by lens element 130 travels
along ray path 134 and is focused along ray path 136 towards focus
138. In some embodiments, lens element 130 and lens element 120
have the same focal length so that focus 138 is at the same point
as focus 128 on optical axis 140. Thus, portion 125 of the aperture
of dual lens 110 is occupied by lens element 120 and another
aperture-portion, defined by sub-aperture 122, is occupied by lens
element 130.
[0022] In some embodiments, dual lens 110 may be attached to focus
mechanism 150, which can move lens 110 along direction 152, in
order to move positions 128 and 138 along optical axis 140,
adjusting the focus.
[0023] FIG. 1B is an axial view of lens 110, including lens element
120, sub-aperture 122, lens element 130, and optical axis 140. In
some embodiments, lens elements 120 and 130 are circular and
concentric. In some embodiments, sub-apertures such as sub-aperture
122 are not circular (e.g., rectangular, oval), and are not
necessarily concentric with lens elements such as lens element
120.
[0024] FIG. 2 is a plan view of complex dual-band lens 200. Dual
band lens 200 includes optical subsystem 210 and optical subsystem
220. Optical subsystem 210 is a doublet, formed of lens element 211
and lens element 212. Sub-aperture 213 is cut-through optical
system 210. Incoming light travels along ray path 214, is refracted
by optical subsystem 210, and converges along paths represented by
ray path 216, to focus 218. Of course, optical sub-systems 210 and
220 could be of any optical system forms, including systems with
several lenses. Optical subsystems 210 and 220 could have finite
objects, be afocal, or have any desired optical functions.
[0025] Optical subsystem 220 includes lens elements 221, 222, and
223. Optical subsystem 220 fits substantially within sub-aperture
213. Light travels along ray path 224, and converges along ray path
226 to focus 228. If optical systems 210 and 220 have the same
focal length, then focus 218 and focus 228 are at the same point
along optical axis 240. However, in some embodiments, optical
subsystems have different focal lengths, are shapes other than
circular (e.g. square, oval), or may be eccentric (rather than
concentric).
[0026] Optical subsystem 210 and optical subsystem 220 are designed
to accept and operate on light of different wavelengths, so that
images 218 and 228 are formed of light from different wavelength
bands.
[0027] FIG. 3 is a plan view of a dual band lens, according to the
present invention. In lens 300, lens elements 310, 312, 314, and
316, form optical subsystem 317, suitable for imaging light of one
wavelength band, for example an infrared band. Light enters along
ray path 320 and converges to image 322 on optical axis 360. Image
recording device 318, for example a focal plane or film, receives
image 318. Lens elements 310 and 312 have cut-out sub-apertures 311
and 313.
[0028] Lens elements 330, 332, 334, and 336 form optical subsystem
337, suitable for imaging light a second wavelength band, for
example a visible band. Lens element 330 is fixed inside the
sub-aperture of lens element 310 and lens elements 334 and 336 are
fixed in the sub-aperture of lens element 312. Light travels along
ray path 342, is brought out from optical axis 360 by fold element
338 (e.g., mirror, prism), and focuses at image 344. Image
recording device 340 is placed to receive image 344.
[0029] In some embodiments, other configurations are used to reach
image 344. In some embodiments, image 344 is formed on optical axis
360, and imaging device 340 is placed on optical axis 360, similar
to the elements of optical system 337. In some embodiments, one
imaging device records both optical bands. Many different fold
configurations can be used to direct image 344 or image 322 to
different paths or locations.
[0030] It can be seen that lens elements 314 and 316 are not
cut-out. Also, it can be seen that element 332 is not secured
within a sub-aperture. Thus, many different element types or
elements placed in different locations can be used to form a dual
band system, according to the present invention.
[0031] Lens elements 310 and 330 form focusing element 346.
Focusing mechanism 348, which can be any of a number of electronic
or mechanical devices (e.g., motor, cam, screw), moves element 346
along path 350 to adjust the focus of both images 322 and 344 at
the same time. Because one motion focuses light along both paths
320 and 342 at the same time and by the same amount, changes in
object distance can be corrected for both optical subsystems 317
and 337. Because subsystems 317 and 337 are coaxial, there is no
parallax.
[0032] TABLE 1A through TABLE 1B contain a prescription (performed
on the ZEMAX lens design software of Focus Software of Tucson,
Ariz.) for an embodiment of a dual infrared and visible optical
system, according to the present invention. Optical subsystem 317,
having the larger aperture, is the infrared subsystem, described in
TABLE 1A and TABLE 1B. Making the infrared optical subsystem 317
with the larger portion of the aperture can help with diffraction
blur, which is worse in the longer wavelengths of the infrared. Of
course, this effect also depends on the diameter of subsystem 337.
The visible elements are described in TABLE 1C. TABLE 1D describes
possible focus positions from infinity to near-focus.
1TABLE 1A IR SURFACE DATA Surf Type Radius (mm) Thick (mm) Glass
Dia (mm) Conic OBJ STD Infinity Infinity 0 0 1 STD Infinity 50
61.16146 0 2 STD 63.42498 6 AMTIR4 50.90581 -0.7739041 3 STD
750.2383 10 50.1996 0 4 STD -49.07076 4.5 AMTIR4 41.75451 0 STO
BIN_2 -86.2833 27.60546 42.75661 6.517522 6 STD 21.78942 5 AMTIR4
21.75929 0 7 STD 23.31248 11.76972 18.13065 1.586647 8 STD Infinity
1 GE_LONG 11.01212 0 9 STD Infinity 0 10.84075 0 IMA STD Infinity
10.84075 0
[0033]
2 TABLE 1B SURFACE DATA DETAIL Surface STO: BINARY_2 Diffract
Order: 1 Coeff on r 2: 0 Coeff on r 4: -2.9405054e-006 Coeff on r
6: 2.0090442e-009 Coeff on r 8: 6.3599093e-014 Coeff on r 10:
1.9619292e-015 Maximum term: 4 Maximum rad ap: 28 Term on P to 2:
-71.430552 Term on P to 4: -194.74879 Term on P to 6: 744.14389
Term on P to 8: -685.68238
[0034]
3TABLE 1C Visible SURFACE DATA Surf Type Radius (mm) Thick (mm)
Glass Dia (mm) Conic OBJ STD Infinity 6.8e+009 1.4959e+9 0 1 STD
36.79642 1.36 F2 12 0 2 STD 388.6092 8.5 12 0 STO STD -17.34062
0.68 FK5 9 0 4 STD 16.56215 6.084034 9 0 5 STD -933.3208 3.4 SK5 12
0 6 STD -8.625559 3.4 SF11 12 0 7 STD -17.53535 0.1 12 0 8 STD
47.34954 3 BK7 12 0 9 STD -22.6334 1 12 0 10 STD Infinity 6.35 BK7
12.7 0 11 CDBRK -- 0 -- -- 12 STD Infinity 0 MIRROR 17.96051 0 13
CBRK -- -6.35 -- -- 14 STD Infinity -23.55 12.7 0 IMA STD Infinity
5.814062 0
[0035]
4 TABLE 1D MULTI-CONFIGURATION DATA: Configuration 1: 1 Thickness
0: 1e+010 2 Thickness 3: 10 Configuration 2: 1 Thickness 0: 3000 2
Thickness 3: 10.58457 Variable Configuration 3: 1 Thickness 0: 1000
2 Thickness 3: 11.80299 Variable
[0036] FIG. 4A is a plan view of a dual band zoom lens, according
to the present invention. A zoom lens typically consists of a focus
group, a zoom group, a variator group, and a fixed group. Dual
wavelength zoom lens 400 includes focus group 410, variator group
420, compensator group 430, and fixed lenses 442, 444, and 445.
[0037] In some embodiments, lens 400 images visible and infrared
light. In such an embodiment, focus group 410 is made up of
infrared element 412 and a visible doublet formed of elements 414
and 415; variator group 420 is made up of infrared element 422 and
a visible doublet formed of elements 424 and 425; compensator group
430 is made up of infrared element 432 and a visible doublet formed
of elements 434 and 435. In some embodiments, reflective element
440 is used to bend the visible optical path away from original
optical axis 402, thus providing physical access to the visible
optical path, separate from the infrared optical path. Element 442
is a fixed group for the infrared channel and elements 444 and 445
form a visible doublet fixed group for the visible channel. Thus,
motion of group 410 controls focus, motion of group 420 controls
focal length, motion of group 430 compensates for motion of group
420, and fixed elements 442, 444, and 445 complete the imaging
sub-systems. Motions of the focus, variator, and compensator groups
in a zoom lens are typically accomplished by rotating cams or
individual motors.
[0038] Infrared light travels along an infrared optical path,
through an optical subsystem formed of elements 412, 422, 432, and
442, coming to a focus at point 443. Visible light travels along a
visible optical path, through an optical subsystem formed of
elements 414, 415, 424, 425, 434, 435, 444, and 445, and comes to a
focus at point 446. A portion of the infrared lens elements,
elements 412, 422, and 432, have central apertures, near to which a
portion of the visible elements 414, 415, 424, 425, 434, and 435
have been fixed. Those skilled in the art will recognize that FIG.
4A is illustrative of many possible designs, and that additional
fixed or moving lens elements can be added to, or elements can be
modified in, either or both the infrared or visible channel, to
adjust the optical properties of lens 400.
[0039] TABLE 2A is a prescription for the infrared subsystem of an
embodiment of lens 400, as described by the ZEMAX optical design
software of Focus Software of Tucson, Ariz. TABLE 2B is a
prescription for the visible subsystem of an embodiment of lens
400.
5TABLE 2A Surf Type Radius Thick Glass Dia (mm) Conic OBJ STANDARD
Infinity Infinity 1 STANDARD 72.68131 6 AMTIR4 52 1.081439 2
BINARY_2 2847.093 1 52 3 STANDARD Infinity 1.893045 28.30202 4
STANDARD -46.08221 2.4 AMTIR4 30 -6.43137 5 BINARY_2 53.02568
17.95646 30 -1.562856 6 STANDARD 45.52305 5 AMTIR4 42 -4.07756 7
BINARY_2 214.604 8.951938 42 -2.800258 STO STANDARD Infinity
19.3061 36.48307 9 EVENASPH 50.59115 4 AMTIR4 37 -1.510571 10
BINARY_2 669.0731 25.14 37 11 STANDARD Infinity 1 GE_LONG 11.75859
12 STANDARD Infinity 0.5 11.5516 IMA STANDARD Infinity 11.09906
[0040]
6TABLE 2B Surf Type Radius (in) Thickness (in) Glass Diameter (in)
Conic OBJ STD Infinity 3.937008e+8 2.16443e+8 0 1 STD 0.9536221
0.03937008 F2 0.6299213 0 2 STD 0.4923513 0.1968504 BK7 0.6299213 0
3 STD -3.961359 0.03937008 0.6299213 0 4 STD Infinity 0.07452756 0
0 5 STD -0.7321447 0.05511811 SF6 0.4724409 0 6 STD -0.3410998
0.03937008 LAKN12 0.4724409 0 7 STD 0.6637404 0.7069472 0.4724409 0
STO STD 0.9835458 0.03937008 LAF2 0.3937008 0 9 STD 0.3407645
0.1574803 SK4 0.3937008 0 10 STD -2.749945 0.1949031 0.3937008 0 11
STD Infinity 0 0 0 12 STD 1.683481 0.07874016 SF57 0.4724409 0 13
STD 0.5892404 0.04897531 0.4724409 0 14 STD 0.7205954 0.1574803
LAKN12 0.4724409 0 15 STD -0.7043201 0.1574803 0.4724409 0 16 CBRK
-- 0 -- -- -- 17 STD Infinity 0 MIRROR 0.5497474 0 18 CBRK --
-0.8267717 -- -- -- IMA STD Infinity 0.3287124 0
[0041]
7 TABLE 3 Aperture: Circular Aperture Minimum Radius: 0 Maximum
Radius: 25.2 mm Surface 2: BINARY_2 Diffract Order: 1 Coeff on r 2:
0 Coeff on r 4: 8.6438078e-007 Coeff on r 6: -1.1018959e-010
Maximum term: 1 Maximum rad ap: 26 mm Term on P to 2: -47.916994
Aperture: Floating Aperture Maximum Radius: 26 mm Aperture:
Circular Aperture Minimum Radius: 0 Maximum Radius: 14.2 mm Surface
5: BINARY_2 Diffract Order: 1 Coeff on r 2: 0 Coeff on r 4:
-2.0200256e-006 Coeff on r 6: 6.5985686e-010 Maximum term: 1
Maximum rad ap: 15 Term on P to 2: 39.46 Aperture: Floating
Aperture Maximum Radius: 15 Surface 7: BINARY_2 Diffract Order: 1
Coeff on r 2: 0 Coeff on r 4: -2.0632414e-006 Coeff on r 6:
1.8567942e-009 Maximum term: 1 Maximum rad ap: 21 Term on P to 2:
-34.195207 Aperture: Floating Aperture Maximum Radius: 21 Surface
9: EVENASPH Coeff on r 2: 0 Coeff on r 4: -7.3770432e-006 Coeff on
r 6: -1.3774416e-008 Aperture: Circular Aperture Minimum Radius: 0
Maximum Radius: 17.6 Surface 10: BINARY_2 Diffract Order: 1 Coeff
on r 2: 0 Coeff on r 4: -7.4626349e-006 Coeff on r 6:
-8.4132712e-009 Coeff on r 8: 0 Maximum term: 1 Maximum rad ap:
18.5 Term on P to 2: -30.9673 Aperture: Floating Aperture Maximum
Radius: 18.5
[0042] FIG. 4B-FIG. 4E illustrate the motion of infrared subsystem
elements 412, 422, and 432, relative to fixed element 442, through
zoom. TABLE 4A describes the zoom motions of the infrared subsystem
within lens 400, as shown in FIG. 4B-FIG. 4E. Configurations 1
through 4 in TABLE 4A correspond to FIG. 4B through FIG. 4E.
8TABLE 4A MULTI-CONFIGURATION DATA: Configuration 1: 1 Stop Surf: 8
2 Aperture (mm): 25 3 Thickness (mm): 1.176e+010 4 Field vdy 2:
-0.01516838 5 Field vcy 2: 0.01517066 6 Field vdy 3: -0.007223461 7
Field vcy 3: 0.07068578 8 Y-field 2: 10.76 9 Y-field 3: 15.37 10
Thickness 2: 1 11 Thickness 3: 1.893045 Variable 12 Thickness 5:
17.95646 Variable 13 Thi So P2 7: 36.20144 Variable Configuration
2: 1 Stop Surf: 8 2 Aperture: 42 3 Thickness 0: 1.176e+010 4 Field
vdy 2: 0.02730892 5 Field vcy 2: 0.06378812 6 Field vdy 3:
0.04207523 7 Field vcy 3: 0.1277079 8 Y-field 2: 6.251 9 Y-field 3:
8.93 10 Thickness 2: 1 Pick up from configuration 1, operand 10,
scale 1, offset 0 11 Thickness 3: 12.15629 Variable 12 Thickness 5:
11.89784 Variable 13 Thi So P2 7: 36.20144 Pick up from
configuration 1, operand 13, scale 1, offset 0 Configuration 3: 1
Stop Surf: 1 2 Aperture: 50 3 Thickness 0: 1.176e+010 4 Field vdy
2: -0.05037608 5 Field vcy 2: 0.05038193 6 Field vdy 3: -0.06996329
7 Field vcy 3: 0.0699695 8 Y-field 2: 3.666 9 Y-field 3: 5.237 10
Thickness 2: 1 Pick up from configuration 1, operand 10, scale 1,
offset 0 11 Thickness 3: 17.84855 Variable 12 Thickness 5: 2 13 Thi
So P2 7: 36.20144 Pick up from configuration 1, operand 13, scale
1, offset 0 Configuration 4: 1 Stop Surf: 1 2 Aperture: 50 3
Thickness 0: 600 4 Field vdy 2: -0.0212013 5 Field vcy 2:
0.02120325 6 Field vdy 3: -0.04582351 7 Field vcy 3: 0.04582863 8
Y-field 2: 3.666 9 Y-field 3: 5.237 10 Thickness 2: 4.592189
Variable 11 Thickness 3: 17.84855 Pick up from configuration 3,
operand 11, scale 1, offset 0 12 Thickness 5: 2 Pick up from
configuration 3, operand 12, scale 1, offset 0 13 Thi So P2 7:
36.20144 Pick up from configuration 1, operand 13, scale 1, offset
0
[0043] FIG. 4F-FIG. 4I illustrate the motions of visible subsystem
elements 414, 415, 424, 425, 434, and 435, relative to fixed
elements 444 and 445, in dual band lens 400. TABLE 4B describes the
zoom motions of the infrared subsystem within lens 400.
Configurations 1 through 4 in TABLE 4B correspond to FIG. 4F
through FIG. 41. In some embodiments, the motions of the
corresponding visible and infrared elements will be the same, in
order to provide the same zoom and focus changes to both the
visible and infrared channels.
9 TABLE 4B Configuration 1: 1 Stop Surf: 8 2 Aperture: 0.1968504 3
Thickness 0: 3.937008e+008 4 Field vdy 2: -0.02025824 5 Field vdy
3: -0.002123443 6 Field vcy 2: 0.02025998 7 Field vcy 3: 0.1714582
8 Y-field 2: 10.76 9 Y-field 3: 15.37 10 Thickness 3: 0.03937008 11
Thickness 4: 0.07452756 12 Thickness 7: 0.7069472 Configuration 2:
1 Stop Surf: 8 2 Aperture: 0.3228346 3 Thickness 0: 3.937008e+008 4
Field vdy 2: 0.1880455 5 Field vdy 3: 0.4631203 6 Field vcy 2:
0.1880653 7 Field vcy 3: 0.4897827 8 Y-field 2: 6.251 9 Y-field 3:
8.93 10 Thickness 3: 0.03937008 11 Thickness 4: 0.4785941 12
Thickness 7: 0.4684189 Configuration 3: 1 Stop Surf: 5 2 Aperture:
0.4724409 3 Thickness 0: 3.937008e+008 4 Field vdy 2: 0.0624353 5
Field vdy 3: 0.04725005 6 Field vcy 2: 0.06244235 7 Field vcy 3:
0.2760152 8 Y-field 2: 3.66 9 Y-field 3: 5.237 10 Thickness 3:
0.03937008 11 Thickness 4: 0.7026988 12 Thickness 7: 0.07874016
Configuration 4: 1 Stop Surf: 5 2 Aperture: 0.5905512 3 Thickness
0: 23.62205 4 Field vdy 2: 0.1297347 5 Field vdy 3: 0.09582019 6
Field vcy 2: 0.2561988 7 Field vcy 3: 0.5318 8 Y-field 2: 3.66 9
Y-field 3: 5.237 10 Thickness 3: 0.1807949 11 Thickness 4:
0.7026988 12 Thickness 7: 0.07874016
[0044] FIG. 5 is a plan view of an embodiment of a dual wavelength
camera, according to the present invention. Lens elements 502, 504,
506, and 508 image light of a first wavelength band (e.g., thermal
infrared), forming image 509 on imaging device 510 (e.g., an
infrared focal plane array). Embodiments can, of course,
incorporate many optical forms. Signals from imaging device 510 are
processed by card 512. Processing can also be accomplished by many
other electronic configurations, or (for example) electronics built
into the focal plane.
[0045] Lens elements 514, 516, and 518, and fold 520 image light of
a second wavelength band (e.g., visible), forming image 521 on
imaging device 522 (e.g., CMOS imager, CCD). Signals from imaging
device 522 are processed by card 524. Processing can also be
accomplished by many other electronic configurations, or (for
example) electronics built into the focal plane
[0046] Lens elements 502 and 514 are moved along direction 526 by
focus drive 528, operated by switch 530, to focus objects in scene
532. A manual focus system could also be employed, or switch 530
could represent an auto-focus control. An image of scene 532 in
either or both optical wavelength bands is projected by display 534
(e.g., LCD display, CRT) through eyepiece 536 for viewing by
operator 538. Camera 500 is contained in case 540.
[0047] Mechanism 528 focuses both images 521 and 509 at the same
time and by the same amount. Thus, if both images 509 and 521 are
displayed on display 534, they will remain the same size and
quality as focus is adjusted. The same objects in scene 532 will be
in-focus in both optical wavelength bands. While lens 300 of FIG. 3
is shown in FIG. 5, lens 400 from FIG. 4, or any other
configuration of dual band lens could be used in camera 500.
[0048] Thus, a single, refractive optical system can image two
wavelength bands through the same aperture, compressing required
space and avoiding parallax. Such an optical system can also focus
or zoom images in two different wavelength bands the same amount at
the same time. Thus, images in two wavelength bands can be kept at
constant magnification and identical focus positions, facilitating
common viewing, data processing such as data-fusion, recording, or
other use of a scene, in both wavelength bands.
[0049] While various embodiments of the invention have been
described, it should be understood that they have been presented by
way of example and not limitation. Those skilled in the art will
understand that various changes in forms or details may be made
without departing from the spirit of the invention. Thus, the above
description does not limit the breadth and scope of the invention
as set forth in the following claims.
* * * * *