U.S. patent application number 09/118141 was filed with the patent office on 2001-09-13 for optical filter holder assembly.
Invention is credited to EDWARDS, GLENN R., EL-HAGE, AMER, GARNIERI, PHIL A. JR., MARQUISS, SAMUEL A., MODLIN, DOUGLAS N., TAYLOR, MICHAEL T., WONG, CALVIN D..
Application Number | 20010021074 09/118141 |
Document ID | / |
Family ID | 27584468 |
Filed Date | 2001-09-13 |
United States Patent
Application |
20010021074 |
Kind Code |
A1 |
MARQUISS, SAMUEL A. ; et
al. |
September 13, 2001 |
OPTICAL FILTER HOLDER ASSEMBLY
Abstract
Devices for using optical filters in a filter holder that enable
optical filters to be simply, conveniently, and flexibly
interchanged.
Inventors: |
MARQUISS, SAMUEL A.; (SANTA
CLARA, CA) ; WONG, CALVIN D.; (SAN CARLOS, CA)
; EDWARDS, GLENN R.; (PALO ALTO, CA) ; TAYLOR,
MICHAEL T.; (NEWARK, CA) ; GARNIERI, PHIL A. JR.;
(LOS ALTOS, CA) ; MODLIN, DOUGLAS N.; (PALO ALTO,
CA) ; EL-HAGE, AMER; (MENLO PARK, CA) |
Correspondence
Address: |
KOLISCH HARTWELL DICKINSON MCCORMACK
AND HEUSER
SUITE 200
520 SOUTHWEST YAMHILL STREET
PORTLAND
OR
97204
|
Family ID: |
27584468 |
Appl. No.: |
09/118141 |
Filed: |
July 16, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09118141 |
Jul 16, 1998 |
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09062472 |
Apr 17, 1998 |
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6071748 |
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60052876 |
Jul 16, 1997 |
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60059639 |
Sep 20, 1997 |
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60063811 |
Oct 31, 1997 |
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60072499 |
Jan 26, 1998 |
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60072780 |
Jan 27, 1998 |
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60075414 |
Feb 20, 1998 |
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60075806 |
Feb 24, 1998 |
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60082253 |
Apr 17, 1998 |
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60084167 |
May 4, 1998 |
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60085335 |
May 13, 1998 |
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60085500 |
May 14, 1998 |
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Current U.S.
Class: |
359/892 |
Current CPC
Class: |
B01J 2219/00605
20130101; B01J 2219/00612 20130101; Y10S 436/809 20130101; Y10S
436/807 20130101; B01L 2300/0829 20130101; C40B 60/14 20130101;
B01L 9/523 20130101; B01J 2219/00315 20130101; B01J 2219/00707
20130101; B01J 2219/00317 20130101; B82Y 15/00 20130101; Y10T
436/11 20150115; Y10T 436/25 20150115; G01N 21/76 20130101; Y10T
436/113332 20150115; B01J 2219/0061 20130101; B01J 2219/00659
20130101; Y10T 436/114165 20150115; Y10T 436/115831 20150115; B01J
2219/00686 20130101; B01J 2219/00691 20130101 |
Class at
Publication: |
359/892 |
International
Class: |
G02B 005/22; G02B
007/00 |
Claims
We claim:
1. A device for holding an optical filter, the device comprising: a
filter barrel having an inner wall and a stop structure; a
removable annular friction member inside the filter barrel; and at
least one optical filter sandwiched between the stop structure and
the friction member, wherein the friction member is held in place
relative to the inner wall by static friction, without any thread,
groove, or adhesive.
2. The device of claim 1, wherein the inner wall is substantially
parallel to the optical filter.
3. The device of claim 1, wherein the inner wall has a funnel
portion that graduates in diameter in a direction progressing away
from the stop structure.
4. The device of claim 1, wherein the friction member is a
compressible ring having an uncompressed outer diameter greater
than the inner diameter of the inner wall.
5. The device of claim 4, wherein the compressible ring exerts a
force on the inner wall that provides sufficient static friction to
hold the optical filter snugly in place during routine use, while
also permitting easy removal when replacing optical filters.
6. The device of claim 1, wherein the optical filter is an
intensity filter, a spectral filter, or a polarization filter.
7. A tool device for loading an optical filter into a holder, the
device comprising a funnel structure having a top end and a lower
edge configured to rest on top of a filter holder, wherein the
funnel structure has an inner diameter that enlarges gradually in a
direction from the lower edge toward the top end.
8. The device of claim 7, further comprising a slug for applying
pressure to a friction member when loading the optical filter,
wherein the slug and the optical filter have approximately
equivalent peripheral dimensions.
9. An optical filter holder system, the system comprising: a holder
having a plurality of apertures; and first and second sets of
filter cartridges configured to fit in the apertures, each of the
first set of filter cartridges having an optical filter permanently
fixed in the filter cartridge, each of the second set of filter
cartridges having a mechanism that permits easy replacement of
different optical filters in the same filter cartridge.
10. The system of claim 9, wherein the holder includes a filter
wheel.
11. The system of claim 9, wherein each of filter cartridges has a
lower portion that is threaded to screw into any one of the
apertures.
12. The system of claim 9, wherein the mechanism comprises: a
filter barrel having an inner wall and a stop structure; and a
removable annular friction member inside the filter barrel, wherein
an optical filter can be sandwiched securely inside the filter
barrel between the stop structure and the friction member, wherein
the friction member is held in place relative to the inner wall by
static friction, without any thread, groove, or adhesive.
13. An optical filter wheel module, the module comprising: an
optical filter wheel that is rotatable around a hub structure; and,
a wheel case having a static portion and a removable portion, and
at least one set of windows for transmitting light through the
wheel case and through a selected optical filter contained in the
optical filter wheel, wherein the hub structure is built into the
removable portion of the wheel case.
14. The module of claim 13, wherein the wheel case is substantially
light-tight, except for light that is transmitted through the
windows.
15. The module of claim 13, wherein the windows are in the static
portion of the wheel case.
16. The module of claim 13, wherein the windows are in the
removable portion of the wheel case.
17. The module of claim 13, wherein the wheel case has a second set
of windows, the sets of windows being located on opposite sides of
the hub structure, so that any given optical filter in the optical
filter wheel can be rotated into alignment with either set of
windows.
18. The module of claim 13, further comprising a post-to-hole
mating structure that aligns the portions of the wheel case.
19. The module of claim 13, wherein the static portion of the wheel
case is fixed to an instrument platform.
20. The module of claim 13, further comprising a driver mechanism
configured to rotate the optical filter wheel.
21. A device for holding an optical filter, the device comprising:
a base having a hub structure; and an elongate filter cartridge
having a filter end and a pivot end, the filter end configured to
hold at least one optical filter, the pivot end configured turnably
to attach to the hub structure, so that an optical filter can be
turned between two positions about the hub structure.
22. The device of claim 21, wherein the filter end is configured to
hold two optical filters side by side, so that either optical
filter can be aligned with a selected position about the hub
structure.
23. The device of claim 21, wherein the base substantially
surrounds the elongate filter cartridge on at least one side, the
base including at least one window for transmitting light through
the base and through a selected optical filter aligned with the
window.
24. The device of claim 21, wherein the base is configured to limit
the angle through which the elongate filter cartridge may turn.
25. The device of claim 21, wherein the elongate filter cartridge
generally is fan shaped, the filter end being wider than the pivot
end.
26. The device of claim 21, further including a driver mechanism
configured to turn the elongate filter cartridge.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of the following patent
applications, each of which is incorporated herein by reference:
U.S. patent application Ser. No. 09/062,472, filed Apr. 17, 1998;
and PCT Patent Application Ser. No. ______, filed Jul. 15, 1998,
titled LIGHT DETECTION DEVICE, and naming William B. Burton,
Kimberly L. Crawford, Sudhir S. Deshpande, Glenn R. Edwards, Amer
El-Hage, Todd E. French, Vladimir Lemberg, Joseph S. Leytes, Samuel
a. Marquiss, John W. Meadows, Irina Mineyev, Douglas N. Modlin,
John C. Owicki, Jon F. Peterson, Derrick A. Richardson, Rick V.
Stellnacher, and Michael T. Taylor as inventors.
[0002] This application is based upon and claims benefit under 35
U.S.C. .sctn. 119 of the following U.S. Provisional Patent
Applications, each of which is incorporated herein by reference:
Ser. No. 60/052,876, filed Jul. 16, 1997; Ser. No. 60/059,639,
filed Sep. 20, 1997; Ser. No. 60/063,811, filed Oct. 31, 1997; Ser.
No. 60/072,499, filed Jan. 26, 1998; Ser. No. 60/072,780, filed
Jan. 27, 1998; Ser. No. 60/075,414, filed Feb. 20, 1998; Ser. No.
60/075,806, filed Feb. 24, 1998; Ser. No. 60/082,253, filed Apr.
17, 1998; Ser. No. 60/084,167, filed May 4, 1998; Ser. No.
60/085,335, filed May 13, 1998; Ser. No. 60/085,500, filed May 14,
1998; and Ser. No. 60,089,848, filed Jun. 19, 1998.
[0003] This application incorporates by reference the following
U.S. Patent Applications: Ser. No. ______, filed Jul. 16, 1998,
titled MOVEABLE CONTROL UNIT, and naming Lev J. Leytes, William G.
Burton, Yong Paik, Glenn R. Edwards, Douglas N. Modlin, and Amer-El
Hage; and Ser. No. ______, filed Jul. 16, 1998, titled FLOATING
HEAD ASSEMBLY, and naming Samuel A. Marquiss, Glenn R. Edwards, and
Douglas N. Modlin as inventors.
FIELD OF THE INVENTION
[0004] The invention relates to optical filters. More particularly,
the invention relates to devices for using optical filters in a
filter holder that enable optical filters to be simply,
conveniently, and flexibly interchanged.
BACKGROUND OF THE INVENTION
[0005] Optical systems typically include many components, which
interact to generate, transmit, modify, and detect light. Light may
be generated by light sources, transmitted by optical relay
structures, and detected by detectors. Light may be modified by
optical filters positioned in an optical path in one or both of the
light source and detector ends of the instrument.
[0006] Optical filters modify the intensity, spectrum,
polarization, and other properties of light. "Intensity filters"
modify the intensity of light, where intensity is the amount of
light per unit area per unit time. Intensity filters may absorb
light, dissipating the absorbed energy as heat, or they may reflect
or scatter light. "Spectral filters" modify the spectrum of light,
where spectrum is the wavelength composition of light. Spectral
filters may selectively transmit light of preselected wavelengths
and selectively absorb, reflect, or scatter light of other
wavelengths. A spectral filter may convert light of many colors
into light of one or only a few colors. "Polarization filters"
modify the polarization of light, where polarization is the
direction of the electric field associated with light.
[0007] Different applications or conditions may require different
optical filters. For this reason, filter holders have been
developed that allow one of a plurality of optical filters to be
selected and placed in an optical path. Examples include filter
wheels and filter slides. Unfortunately, these filter holders have
a number of shortcomings. In particular, the number of optical
filters required even for a single application often exceeds the
filter-holding capacity of a given filter holder. Therefore, it
sometimes is necessary to replace the optical filters within a
given filter holder.
[0008] Replacing optical filters may be difficult and
time-consuming. If individual optical filters are affixed
permanently to the filter holder, the entire filter holder may need
to be replaced. If individual optical filters are affixed to
removable filter cartridges within the filter holder, the filter
holder still must be opened, individual filter cartridges removed
and replaced, and the filter holder closed again. In known filter
holders, filter cartridges must be replaced with the filter holder
attached to an associated instrument. Working space may be minimal,
and filter cartridges and other components may be dropped into the
instrument, where they may cause damage and be difficult to
retrieve.
[0009] Replacing optical filters within filter cartridges also may
be difficult and time-consuming. Many or most optical filters are
permanently affixed to any associated filter cartridge, and may not
be replaced at all. Other optical filters may be removably affixed
to an associated filter cartridge, but replaceable only with a
limited selection or number of filters. Filter cartridges with
removable optical filters may employ a retaining ring that fits
into a groove on the inside of the filter cartridge to hold the
optical filter. The groove establishes a predetermined position for
the retaining ring, and may limit the thickness or number of
replacement filters. Optical filters that are thicker than the
provided space will not fit, and optical filters that are thinner
than the provided space may require spacers. Filter cartridges with
removable optical filters also may employ a threaded retention
member that can be screwed into the filter cartridge until a point
where it holds the optical filter. This approach may require extra
tools and be time-consuming. This approach also may force the
retaining ring into a plane that is slightly skewed relative to the
filter, misaligning the optical filter.
SUMMARY OF THE INVENTION
[0010] The present invention addresses these and other shortcomings
by providing filter cartridges and filter holders that enable
optical filters to be simply, conveniently, and flexibly
interchanged.
[0011] In one embodiment, the invention provides a device for
holding an optical filter that includes a filter barrel having an
inner wall and a stop structure, a removable annular friction
member inside the filter barrel, and at least one optical filter
sandwiched between the stop structure and the friction member. In
this embodiment, the friction member is held in place relative to
the inner wall by static friction, without any thread, groove, or
adhesive. The filter barrel and friction member may take a variety
of forms and may hold optical filters of various sizes and numbers.
The friction member may hold the optical filter snugly in place
during routine use, while also permitting easy removal when
replacing optical filters.
[0012] In another embodiment, the invention provides a tool device
for loading an optical filter into a holder. The device includes a
funnel structure having a top end and a lower edge configured to
rest on top of a filter holder. The funnel structure includes an
inner diameter that enlarges gradually in a direction from the
lower edge toward the top end. The device also may include a slug
for applying pressure to a friction member when loading the optical
filter.
[0013] In yet another embodiment, the invention provides an optical
filter holder system that includes a holder having a plurality of
apertures, and two sets of filter cartridges configured to fit in
the apertures. The first set of filter cartridges includes an
optical filter permanently fixed in the filter cartridge. The
second set of filter cartridges includes a mechanism that permits
easy replacement of different optical filters in the same filter
cartridge. The filter holder may include a filter wheel, and the
mechanism that permits easy replacement my include a filter barrel
and friction member.
[0014] In yet another embodiment, the invention provides an optical
filter wheel module including an optical filter wheel that is
rotatable around a hub structure, and a wheel case having a static
portion and a removable portion and at least one set of windows for
transmitting light through the wheel case and through a selected
optical filter contained in the optical filter wheel. The hub
structure is built into the removable portion of the wheel case.
The wheel case may be light tight and include more that one set of
windows.
[0015] In yet another embodiment, the invention provides a device
for holding an optical filter comprising a base having a hub
structure, and an elongate filter cartridge having a filter end and
a pivot end, the filter end configured to hold at least one optical
filter, the pivot end configured turnably to attach to the hub
structure, so that an optical filter can be turned between two
positions about the hub structure.
[0016] The invention will be understood more readily after
consideration of the drawings and the detailed description of the
invention that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a partially exploded perspective view of an
optical filter wheel assembly constructed in accordance with the
invention.
[0018] FIG. 2 is a partially exploded perspective view of a portion
of an optical filter wheel assembly like that shown in FIG. 1,
showing a mechanism by which short filter cartridges may be
removed.
[0019] FIG. 3 is a partially exploded perspective view of the
portion of the optical filter wheel assembly shown in FIG. 2,
showing a mechanism by which tall filter cartridges may be
removed.
[0020] FIG. 4 is a perspective view showing a mechanism by which
optical filters may be placed in a tall filter cartridge.
[0021] FIG. 5 is a perspective view showing a mechanism by which a
friction member may be pressed into place using a funnel and
slug.
[0022] FIG. 6 is a top view of a short filter cartridge constructed
in accordance with the invention.
[0023] FIG. 7 is a cross-sectional view of the short filter
cartridge, taken generally along the line 7-7 in FIG. 6.
[0024] FIG. 8 is a top view of a short filter cartridge constructed
in accordance with the invention.
[0025] FIG. 9 is a cross-sectional view of the short filter
cartridge, taken generally along the line 9-9 in FIG. 8.
[0026] FIG. 10 is a top view of a funnel structure constructed in
accordance with the invention.
[0027] FIG. 11 is a cross-sectional view of the funnel structure,
taken generally along the line 11-11 in FIG. 10.
[0028] FIG. 12 is a partial perspective view of an alternative
filter holder assembly constructed in accordance with the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0029] FIG. 1 shows a partially exploded perspective view of an
optical filter wheel assembly 20 constructed in accordance with the
present invention. Optical filter wheel assembly 20 includes a
filter wheel 22 that is rotatable about a hub structure 24, and a
wheel case having a static base portion 26 and a removable lid
portion 28. Hub structure 24 is built into removable lid portion
28.
[0030] Filter wheel 22 holds filter cartridges 30. Filter wheel 22
is substantially circular and includes a plurality of apertures 32
disposed symmetrically about its outer perimeter 34. Apertures 32
are used for mounting filter cartridges 30 and may hold the filter
cartridges via friction, threads, or other means. Filter wheel 22
may have a variety of shapes, and apertures 28 may be disposed in a
variety of configurations, although a symmetric embodiment is
preferred for balance and ease of rotation about hub structure
24.
[0031] Removable lid portion 28 holds filter wheel 22. Removable
lid portion 28 is substantially rectangular, with an enclosed top
36 and sides 38a-d and an open bottom 40 for receiving filter wheel
22. Opposed flanges 42 extend downward from one pair of opposed
sides 38b,d of removable lid portion 28 to support hub structure
24. Filter wheel 22 is rotatably mounted through its center on hub
structure 24.
[0032] Static base portion 26 holds removable lid portion 28 and
filter wheel 22. Static base portion 26 is substantially
rectangular, with an enclosed bottom 44 and sides 46a-d and an open
top 48 for receiving filter wheel 22. Opposed slots 50 extend
downward into one pair of opposed sides 46b,d of static base
portion 26 to receive opposed flanges 42. Opposed posts 52 extend
upward from the other pair of opposed sides 46a,c of static base
portion 26 to be received by opposed holes 54 in opposed sides
38a,c of removable lid portion 28. Flanges 42 and slots 50, and
posts 52 and holes 54, individually and collectively form a
post-to-hole mating structure that aligns static base portion 26
and removable lid portion 28 when the two portions are mated
together to form the wheel case. Captive screws 56 situated in
holes 54 and accessible from top 36 may be threaded into posts 52
to hold together removable lid portion 28 and static base portion
26. Static base portion 26 further may be fixed to an instrument
platform to form a portion of a light source module, detector
module, or other optical assembly, among other applications.
[0033] The assembled wheel case is substantially light-tight,
except for light that is transmitted through two sets of opposed
windows 58 included in static base portion 26. Windows 58 are used
for transmitting light through the wheel case and through a
selected optical filter contained in a filter cartridge 30 in
filter wheel 22. Windows 58 are located on opposite sides of hub
structure 24, so that any given optical filter in filter wheel 22
can be rotated into alignment with either set of windows. In turn,
light sources, detectors, and other optical components can be
aligned with either or both sets of filters. Generally, the wheel
case includes at least one set of windows, which may be located on
the static portion, removable portion, or other portion of the
wheel case.
[0034] Filter wheel 22 may be rotated by a drive motor 60, which is
attached to removable lid portion 28 in optical filter wheel
assembly 20. Drive motor 60 or other driver mechanisms also may be
operatively connected to optical filter wheel assembly 20 at other
points and in other manners.
[0035] FIG. 1 also shows a mechanism by which optical filter wheel
assembly 20 may be disassembled and reassembled. Optical filter
wheel assembly 20 is disassembled as follows. First, any associated
instrument is powered down and unplugged. Second, any secondary
housing enclosing optical filter wheel assembly 20 is removed.
Third, drive motor 60 is unplugged at its inline connector 62.
Fourth, captive screws 56 are loosened. Finally, removable lid
portion 28 and filter wheel 22 are pulled out of static base
portion 26.
[0036] Optical filter wheel assembly 20 may be reassembled as
follows. First, filter cartridges 30 are checked to verify that
they are properly seated in filter wheel 22, and filter wheel 22 is
checked to verify that it rotates smoothly about hub structure 24
when moved by hand. Second, removable lid portion 28 and filter
wheel 22 are inserted into static base portion 26, aligning flanges
42 with slots 50, and posts 52 with holes 54. Third, captive screws
56 are tightened. Fourth, drive motor 60 is plugged back in at
inline connector 62. Fifth, any secondary housing is replaced.
Finally, any associated instrument is plugged back in and powered
up, if desired.
[0037] FIG. 2 shows a partially exploded perspective view of a
removable portion 80 of an optical filter wheel assembly, including
a filter wheel 82, removable lid portion 84, and drive motor 86.
Filter wheel 82 includes a set of "short" filter cartridges 88 and
a set of "tall" filter cartridges 90. Filter wheel 82 may hold a
variety of filter cartridges, so long as the filter cartridges are
configured to fit in apertures 92 in the filter wheel. Generally,
opposed apertures in filter wheel 82 should contain matching filter
cartridges or a suitable slug to balance the filter wheel and to
prevent unfiltered radiation from reaching a detector.
[0038] FIG. 2 also shows a mechanism by which short filter
cartridges 88 may be removed and replaced. Generally, short filter
cartridges 88 include an optical filter 94 permanently affixed by
suitable means, such as glue, to a short filter barrel 96 having a
low profile. Optical filter 94 may include an intensity filter, a
spectral filter, or a polarization filter, among others. Short
filter cartridges 88 are removed from filter wheel 82 as follows.
First, with the filter wheel removed as described above, the
desired short filter cartridge is located by sight or by location.
(Filter cartridge locations within the filter wheel may be marked
on the filter wheel or elsewhere for reference.) Second, the short
filter cartridge is removed by turning it counter-clockwise, which
unscrews it. The short filter cartridge may be turned by hand or by
a special tool, such as a spanner wrench 98 having prongs 100 that
engage grooves 102 in the sides of the short filter cartridge 104.
Finally, filter changes are noted on the filter wheel or elsewhere
and in any associated instrument software. Short filter cartridges
88 may be replaced in filter wheel 82 by reversing the process,
turning the short filter cartridge clockwise.
[0039] FIG. 3 shows a partially exploded perspective view of a
removable portion 120 of an optical filter wheel assembly, as shown
in FIG. 2. FIG. 3 also shows a mechanism by which tall filter
cartridges 122 may be removed and replaced. Generally, tall filter
cartridges 122 include an optical filter 124 affixed by a removable
friction member 126 to a tall filter barrel 128. Optical filter 124
may include an intensity filter, a spectral filter, or a
polarization filter, among others. Friction member 126 and tall
filter barrel 128 may be substantially annular. Tall filter
cartridges 122 may be removed from and replaced in filter wheel 130
much like short filter cartridges 88; however, tall filter
cartridges 122 generally are turned by hand rather than by a
tool.
[0040] FIGS. 4 and 5 show a perspective view of a mechanism by
which optical filters may be replaced in the tall filter
cartridges. First, as shown in FIG. 4, the optical filter 150 is
placed in the tall filter barrel 152. Optical filter 150 should be
oriented properly if one side is different than the other.
Additional optical filters 150 can be placed in tall filter barrel
152, if desired. Second, as shown in FIG. 5, a funnel structure 154
is placed on top of tall filter barrel 152. Third, an annular
friction member 156 is placed in funnel structure 154, followed by
a slug 158. Slug 158 and optical filter 150 have approximately
equivalent peripheral dimensions, including radii. Fourth, slug 158
is pushed down through funnel structure 154 to compress friction
member 156, which should fit snugly against optical filter 150.
Finally, slug 158 and funnel structure 154 are removed. The
completed tall filter cartridge then can be installed in a filter
wheel, as described above.
[0041] Optical filter 150 also may be replaced by other techniques.
Generally, the tall filter cartridges incorporate a mechanism that
permits easy replacement of different optical filters in the same
cartridge, enhancing the flexibility of the tall cartridges.
[0042] Optical filter 150 may be removed from the tall filter
cartridge as follows. First, a lint-free cloth is placed on a work
surface. Second, the installed optical filter 150 (or slug 158) is
pushed gently near its center with a gloved finger or thumb, which
will cause the optical filter 150 and friction member 156 to drop
out of tall filter barrel 152. Removed optical filter 150 should be
stored so that it will not become dirty or scratched.
[0043] FIGS. 6 and 7 show detailed views of a short filter
cartridge 180, which includes a short filter barrel 182 and optical
filter 184. Short filter barrel 182 is substantially annular, with
a threaded lower portion 186 that screws into an aperture in a
filter wheel, and a graspable upper portion 188 having a knurled
rim 190 that may be turned by hand. Optical filter 184 is supported
by upper portion 188, and mounts adjacent a stop structure 192 and
inner wall 194 on short filter barrel 182, so that it is
substantially centered relative to short filter barrel 182. Stop
structure 192 includes an edge 196 oriented substantially
perpendicular to a principal plane of optical filter 184 and to
inner wall 194.
[0044] FIGS. 8 and 9 show detailed views of a tall filter cartridge
210, which includes a tall filter barrel 212 and optical filter
214. Tall filter cartridge 210 resembles short filter cartridge 180
in many respects. Tall filter barrel 212 is substantially annular,
with a threaded lower portion 216 that screws into an aperture in a
filter wheel, and a graspable upper portion 218 having a knurled
rim 220 that may be turned by hand. Optical filter 214 is supported
by upper portion 218, and mounts adjacent a stop structure 222 and
inner wall 224. Stop structure 222 includes an edge 226 oriented
substantially perpendicular to a principal plane of optical filter
214 and to inner wall 224. Inner wall 224 may be substantially
perpendicular to the optical filter, as here, or it may have a
funnel portion that graduates in diameter in a direction toward the
stop structure, among other configurations. Lower portion 186 of
short filter barrel 182 is substantially identical to lower portion
216 of tall filter barrel 212. However, upper portion 188 of short
filter barrel 182 is shorter than upper portion 218 of tall filter
barrel 212, giving it a lower profile. In addition, optical filter
182 of short filter barrel 180 is permanently affixed to upper
portion 188, whereas optical filter 212 of tall filter barrel 210
is removably sandwiched in upper portion 218 between stop structure
222 and a friction member 226. Friction member 226 holds optical
filter 212 in place relative to inner wall 224 in tall filter
cartridge 210 by static friction, without any thread, groove, or
adhesive. For this reason, among others, optical filters of various
numbers and sizes may be secured.
[0045] Friction member 226 may take a variety of forms, including a
compressible ring having an uncompressed outer diameter greater
than the inner diameter of inner wall 224. The compressible ring
may exert a force on the inner wall that provides sufficient static
friction to hold an optical filter snugly in place during routine
use, while also permitting easy removal when replacing optical
filters.
[0046] FIGS. 10 and 11 show detailed views of a funnel structure
240, which is used for loading an optical filter into a tall filter
cartridge or other holder as described above. Funnel structure 240
is substantially annular and includes inner and outer walls 242,
244 and a top end 246 and lower edge 248. Lower edge 248 includes a
groove 250 adjacent inner wall 242 configured to rest on top of a
filter cartridge or other holder. The inner diameter of funnel
structure 240 measured between inner walls 242 enlarges gradually
in a direction from lower edge 248 to top end 246.
[0047] FIG. 12 shows a partial perspective view of an alternative
filter holder assembly 270. Filter holder assembly 270 includes an
elongate filter cartridge 272 and a base 274. Elongate filter
cartridge 272 includes a filter end 276 and a pivot end 278. Filter
end 278 is configured to hold optical filters, and includes two
filter slots 280a,b in which optical filters 281 may be glued or
otherwise attached. Generally, the filter end may hold one or more
optical filters, using slots, apertures, short or tall filter
cartridges, or other mechanisms. Filter slots may be left open to
allow light to pass unfiltered, include filters to filter light, or
include slugs or other opaque structures to block light. Pivot end
278 is configured turnably to attach to a hub structure, and
includes an aperture 282 for receiving a drive axle or other pivot
structure. Generally, the pivot end may attach through any means to
any suitable drive mechanism. Elongate filter cartridge 278 is fan
shaped, filter end 276 being wider than pivot end 278, although
other shapes also are possible.
[0048] Base 272 generally supports elongate filter cartridge 272.
Base 272 includes a hub structure 284 and major and walls 286, 287
that substantially surround elongate filter cartridge 272 on all
but one side. Elongate filter cartridge 272 is turnably attached at
its pivot end 278 to hub structure 284 through a drive axle 288,
about which it may turn. Base 272 also includes a window 289 in
major wall 286.
[0049] Elongate filter cartridge 272 may be used for moving an
optical filter in and out of an optical path, much like a filter
wheel or filter slide, by turning elongate filter cartridge 272
about hub structure 284. Because elongate filter cartridge 272 may
move one or a few filters in and out of an optical path by turning
through a limited angle, it may be configured to require less space
than a filter wheel of comparable radius. A drive mechanism 290 may
be controlled or base 274 may be configured to limit the angle
through which elongate filter cartridge 272 may turn. For example,
in filter holder assembly 270, a position 292 on minor wall 287
forms a stop structure that physically limits movement if drive
mechanism 289 attempts to turn elongate filter cartridge 272 past
the wall.
[0050] Accordingly, while the invention has been disclosed in
preferred forms, the specific embodiments thereof as disclosed and
illustrated herein are not to be considered in a limiting sense,
because numerous variations are possible and no single feature,
function, or property of the preferred embodiments are essential.
The invention is to be defined only by the scope of the issued
claims.
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