U.S. patent application number 12/023855 was filed with the patent office on 2009-02-26 for clip-on night vision device.
This patent application is currently assigned to Northrop Grumman Guidance and Electronics Company, Inc.. Invention is credited to Rodney L. DOSTER, Roland M. MORLEY, Kenneth W. SAUTER.
Application Number | 20090052024 12/023855 |
Document ID | / |
Family ID | 39101125 |
Filed Date | 2009-02-26 |
United States Patent
Application |
20090052024 |
Kind Code |
A1 |
SAUTER; Kenneth W. ; et
al. |
February 26, 2009 |
CLIP-ON NIGHT VISION DEVICE
Abstract
A night viewer (10) is adaptable to generate an enhanced image
suitable for viewing through an optical scope (16). An input end
(18) of the viewer (10) receives the image to be enhanced through
an objective lens (20). An image enhancing unit (22) enhances the
image. The enhanced image is optically transmitted from a display
(28) to the ocular lens (24) of the scope (16). The display (28) is
operably connected with the image enhancing unit (22) to display
the enhanced image. A Risley prism (30) located in an image path
(32) is used to controllably adjust and to maintain boresight
alignment (36).
Inventors: |
SAUTER; Kenneth W.;
(Garland, TX) ; DOSTER; Rodney L.; (Garland,
TX) ; MORLEY; Roland M.; (Richardson, TX) |
Correspondence
Address: |
MARSTELLER & ASSOCIATES, P. C.
P. O. BOX 803302
DALLAS
TX
75380-3302
US
|
Assignee: |
Northrop Grumman Guidance and
Electronics Company, Inc.
Los Angeles
CA
|
Family ID: |
39101125 |
Appl. No.: |
12/023855 |
Filed: |
January 31, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11423897 |
Jun 13, 2006 |
7359114 |
|
|
12023855 |
|
|
|
|
Current U.S.
Class: |
359/426 |
Current CPC
Class: |
G02B 23/12 20130101;
F41G 11/003 20130101; F41G 1/38 20130101 |
Class at
Publication: |
359/426 |
International
Class: |
G02B 23/12 20060101
G02B023/12 |
Claims
1. A focusable night viewer device adaptable to receive an image to
be enhanced of a scene to be viewed, the invention comprising: an
objective lens assembly for gathering light forming the image of
the scene to be viewed; an image enhancing unit for enhancing the
image into a desired format; the image to be enhanced received at
an input end of the image enhancing unit; an output image display
unit operably connected with the image enhancing unit for viewing
of the enhanced image by a user; focusing means controllable by a
user for moving a focus cell assembly mounted between the objective
lens assembly and the image enhancing unit fore and aft along a
desired optical axis through the objective lens assembly; and,
rotational movement of a user accessible knob assembly about an
axis essentially perpendicular to the optical axis is mechanically
translated into rotational movement of the focus cell to move the
focus cell fore and aft relative to the objective lens assembly
along the desired optical path through the objective lens
assembly.
2. The invention of claim 1 wherein a central axis of the objective
lens and a central axis of the image enhancing unit are
aligned.
3. The invention of claim 1 wherein the focus cell moves along
supported by a track system responsive to a user's control of a
rotatable knob.
4. The invention of claim 1 wherein the focus cell moves guided by
a helical guide means for rotational and translational movement of
the focus cell relative to the objective lens assembly along the
desired optical axis through the objective lens assembly.
5. The invention of claim 4 wherein the helical guide includes
complementary threaded segments formed on a portion of the exterior
of the focus cell and in the interior of the night viewer
device.
6. The invention of claim 1 wherein the knob is tadpole shaped for
enhanced user control.
7. The invention of claim 6 wherein the rotational movement of the
knob is mechanically transmitted to a rack for moving a spur gear
attached to the focus cell.
8. A method for focusing a night viewer device of the type having
an objective lens assembly for gathering light forming the image of
the scene to be viewed, an image enhancing unit for enhancing the
image into a desired format, and, the image to be enhanced received
at an input end of the image enhancing unit, including the steps
of: controllably moving a focus cell assembly of the image
enhancing unit along a desired optical axis through the objective
lens assembly through rotational movement of a user accessible knob
assembly about an axis essentially perpendicular to the optical
axis is mechanically translated into rotational movement of the
focus cell to move the focus cell fore and aft relative to the
objective lens assembly along the desired optical path through the
objective lens assembly.
9. The method of claim 8 wherein the focus cell moves guided by a
helical guide means for rotational and translation al movement of
the focus cell relative to the objective lens assembly along the
desired optical axis through the objective lens assembly.
10. The method of claim 9 wherein the helical guide includes
complementary threaded segments formed on a portion of the exterior
of the focus cell and in the interior of the night viewer
device.
11. The method of claim 8 wherein the knob is tadpole shaped for
enhanced user control.
12. The method of claim 8 wherein the rotational movement of the
knob is mechanically transmitted to a rack for moving a spur gear
attached to the focus cell.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional of U.S. application Ser.
No. 11/423,897, filed on Jun. 13, 2006.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The invention relates to the field of night viewer type
devices for enhancing the image of a scene to be viewed, and more
particularly to weapon mounted night viewer devices suitable for
combined use with known man-portable weapon sights.
[0004] 2. Background Art
[0005] Single unit day/night sights have been used by military and
law enforcement personnel to aim weapons used in both day time and
night time conditions. Typically, a day/night sight includes an
objective lens, a reticle and an eyepiece in series with parallel,
but separate, day and night channels. A channel selector or optical
switch may be used to alternatively direct an image of a target
into the day or night channel.
[0006] In a day/night sight, the objective lens and the eyepiece
may be telescopic to provide a magnified image of the target. The
day channel generally uses ambient light to generate an image of
the target. The image may be projected or electronically conveyed
to a display or to a ocular lens assembly to be viewed by the user.
The night channel generally includes an image intensifier to
generate an illuminated image of the target. The illuminated image
may be likewise projected or electronically conveyed to a display
during night time use to be viewed by the user.
[0007] Risley prisms have been used in the daylight optical path of
the prior dual path devices. U.S. Pat. Nos. 6,169,628 and 6,172,821
teach such a day/night scope with Risley prisms located in the day
branch of the parallel optical path. U.S. Pat. No. 6,111,692
similarly teaches the use in another day/night scope of a Risley
prism located in the optical path between the objective lens and a
movable focus cell group.
[0008] A problem with day/night and other types of combined sights
is the bulk and the added weight of two sighting systems that must
be carried when the unit is being used in the field.
[0009] Also, U.S. Pat. No. 6,111,692 and others disclose in general
moving a focus cell lens group in the X-Y-Z dimensions or
directions relative to a night path or channel of a day/night
scope. Such movement of the focus cell in devices similar to that
disclosed in U.S. Pat. No. 6,111,692 was accomplished through the
use of an eccentric cam and pin arrangement limiting fore and aft
movement of the focus cell to correspond to the rotation of the
cam.
[0010] While the above cited references introduce and disclose a
number of noteworthy advances and technological improvements within
the art, none completely fulfills the specific objectives achieved
by this invention.
DISCLOSURE OF INVENTION
[0011] In accordance with the present invention, a night viewer
device is adaptable to generate an enhanced image of a scene
suitable to be viewed through an optical scope. An input end of the
night viewer device receives the image to be enhanced from an
ocular lens end of the optical scope. An image enhancing unit
enhances the image into a desired format. The image to be enhanced
is optically transmitted from the ocular lens end of the optical
scope and is received by an input end of the image enhancing unit.
An output image display unit operably connected with the image
enhancing unit displays the enhanced image. A Risley prism unit
that is located in an image path through the night viewer device
after a collimating lens assembly of the night viewer device is
used to controllably adjust and to maintain boresight alignment of
the optical scope and image enhancing unit of the night viewer
device.
[0012] A primary objective of the present invention is to provide a
simple and reliable method of setting boresight alignment with a
mechanism that would hold boresight alignment through extended
weapon shock. Also, since the optical sight on the man portable
weapon is normally "boresighted" for accuracy before use, a
removable night viewer device that cooperates with the mounted
scope greatly reduces the need to remove the optical scope or
otherwise changing the boresight alignment of the scope.
[0013] To achieve the necessary precision in alignment and the
necessary robustness of the assembly, these two functions are
separated in the present invention. After the main optical
components, those being the objective lens, image intensifier and
collimator lens, have been secured, the setting and adjustment of
boresight is achieved by rotating a pair of Risley prisms. This
novel concept has proven to be a precise, reliable and simple
method which enables the user to make the necessary assembly and
alignment steps during system maintenance.
[0014] In another embodiment of the present invention, a focusable
night viewer device adapted to receive an image to be enhanced of a
scene to be viewed includes an objective lens assembly for
gathering light forming the image of the scene to be viewed. An
image enhancing unit enhances the image into a desired format. The
image to be enhanced is received at an input end of the image
enhancing unit. An output image display unit is operably connected
with the image enhancing unit for viewing of the enhanced image by
a user. A focusing assembly for controllable moving by a user a
focus cell assembly mounted between the objective lens assembly and
the image enhancing unit fore and aft along a desired optical axis
through the objective lens assembly. Rotational movement of a user
accessible knob assembly about an axis essentially perpendicular to
the optical axis is mechanically translated into rotational
movement of the focus ceil to move the focus cell fore and aft
relative to the objective lens assembly along the desired optical
path through the objective lens assembly.
[0015] The focusing assembly for the focus cell lens group is
readily adjustable both in the field and by the user while at the
same time provides for a greater range of fore and aft movement of
the focus cell than prior art cam and pin focusing devices.
[0016] These and other objects, advantages and preferred features
of this invention will be apparent from the following description
taken with reference to the accompanying drawings, wherein is shown
the preferred embodiments of the invention.
BRIEF DESCRIPTION OF DRAWINGS
[0017] A more particular description of the invention briefly
summarized above is available from the exemplary embodiments
illustrated in the drawing and discussed in further detail below.
Through this reference, it can be seen how the above cited
features, as well as others that will become apparent, are obtained
and can be understood in detail. The drawings nevertheless
illustrate only typical, preferred embodiments of the invention and
are not to be considered limiting of its scope as the invention may
admit to other equally effective embodiments.
[0018] FIG. 1 is a left side elevational view of the night viewer
device mounted on a man-portable weapon in front of a known optical
scope.
[0019] FIG. 2 is a cross-sectional view of the night viewer device
of the present invention taken along a central optical axis.
[0020] FIG. 3 is a left frontal exploded isomeric view of the night
viewer device of the present invention.
[0021] FIG. 4 is a schematic view of the optical path through the
night viewer of the present invention.
[0022] FIG. 5 is a frontal view of the night viewer of the present
invention.
[0023] FIG. 6 is a cross sectional view of an image intensifier
suitable for use in the present invention.
[0024] FIG. 7 is a left rear perspective view of the present
invention exposing a view of a focus cell lens grouping for the
night viewer device.
[0025] FIG. 8 is a bottom isomeric view of a rack assembly unit for
focusing the focus cell lens group.
[0026] FIG. 9 is a cross sectional view showing the optical
components of the present night viewer.
MODE(S) FOR CARRYING OUT THE INVENTION
[0027] So that the manner in which the above recited features,
advantages and objects of the present invention are attained can be
understood in detail, more particular description of the invention,
briefly summarized above, may be had by reference to the embodiment
thereof that is illustrated in the appended drawings. In all the
drawings, identical numbers represent the same elements.
[0028] A mountable clip-on night viewer device ("CNVD") 10 is
adaptable to generate an enhanced image 12 of a scene 14 suitable
to be viewed through a Rifle Combat Optic (RCO) or optical scope
16. An input end 18 of the night viewer device 10 receives the
input image to be enhanced through an objective lens assembly 20.
An image enhancing unit 22 enhances the input image of the scene
into a desired format. The image to be enhanced is optically
transmitted to an ocular lens end 24 of the optical scope 16 after
being received through an input end 26 of the image enhancing unit
22. An output image display unit 28 operably connected with the
image enhancing unit 22 displays the enhanced image 12. A Risley
prism unit 30 is located in an optical image path 32 through the
night viewer device 10 after a collimating lens assembly 34 of the
night viewer device 10. The Risley prism unit 30 is used to
controllably adjust and to maintain boresight alignment 36 of the
optical scope 16 and image enhancing unit 22 of the night viewer
device 10 for accuracy of weapon projectile delivery.
[0029] Additionally, in another embodiment of the present
invention, a focusable night viewer device 10 adapted to receive an
image to be enhanced of a scene 14 to be viewed includes an
objective lens assembly 20 for gathering light forming the image of
the scene 14 to be viewed. An image enhancing unit 22 enhances the
image into a desired format. The image to be enhanced is received
at an input end 18 of the image enhancing unit 22. An output image
display unit 28 is operably connected with the image enhancing unit
22 for viewing of the enhanced image 12 by a user. A focusing
assembly 38 permits controllably moving by & user a focus lens
cell assembly 40 that is mounted between the objective lens
assembly 20 and the image enhancing unit 22 in a fore and aft
direction along a desired central optical axis or image path 32
through the objective lens assembly 20. Rotational movement of a
user accessible knob assembly 42 about an axis 44 essentially
perpendicular to the optical axis 32 is mechanically translated
into rotational movement of the focus cell 40 to move the focus
cell 40 fore and aft relative to the objective lens assembly 20
along the desired optical path 32 through the objective lens
assembly 20.
Mountable Night Viewer Having Risley Prisms for Boresight
Alignment
[0030] The mountable clip-on night viewer device ("CNVD") 10 is
adaptable to generate an enhanced image 12 of a scene 14 suitable
to be viewed through a known Rifle Combat Optic (RCO) or optical
scope 16 that may be found in use by various militaries. The
optical scope 16 thus views the enhanced image 12, rather than the
actual scene 14.
[0031] An input end 18 of the night viewer device 10 receives the
input image to be enhanced through an objective lens assembly 20.
An image enhancing unit 22 enhances the input image of the scene
into a desired format. The image to be enhanced is optically
transmitted to an ocular lens end 24 of the optical scope 16 after
being received through an input end 26 of the image enhancing unit
22. An output image display unit 28 operably connected with the
image enhancing unit 22 displays the enhanced image 12.
[0032] A Risley prism unit 30 is located in an optical image path
32 through the night viewer device 10 after a collimating lens
assembly 34 of the night viewer device 10. The Risley prism unit 30
is used to controllably adjust and to maintain boresight alignment
36 of the optical scope 16 and image enhancing unit 22 of the night
viewer device 10. Generally, the Risley prism unit 30 comprises two
or more complementary Risley prisms 30a and 30b. Rotation of one
prism with regard to another prism adjusts the optical path 32 as
desired to maintain the boresight alignment 32.
[0033] The CNVD 10 of the present invention may be constructed of
light weight materials. The main housing 46 may be injection molded
glass fiber reinforced ULTEM, a material that has been used in many
prior night vision products. Lens barrels 50 may be formed from
aluminum, with a scratch resistant anodized coating applied. All
materials preferably should have been proven to be very durable
against physical and chemical exposure to ail normal military
operating environments, including salt fog, and solutions such as
insect repellents, cleaning solutions and petroleum based
products.
[0034] The objective lens assembly 20 for the CNVD 10 may be a
known 55 mm, F/1.1 Mangin design that offers high optical
performance at low light level conditions and is an extremely
lightweight design.
[0035] A molded rubber hood 52 may cover the objective lens 20
optionally providing mechanical protection to the lens and serving
as a light baffle against stray light from sources outside the
field of view.
[0036] The CNVD collimating lens 34 preferably works with a large
variety of day optics by having a large exit pupil. A flexible
rubber lens hood 54 at the rear ensures that light security between
the CNVD 10 and RCO 16 is maintained. The light exiting the rear 56
of the RCO 16 illuminates the users eyeball only and does not spill
onto the user's face.
[0037] Extremely simple to install, the present CNVD 10 may be
mounted and locked onto a weapon rail mounting system 58 using a
quick-action throw lever mount 66. After a lever 60 is closed, the
device is locked by sliding forward to engage a catch. This
installation is tools free and can typically be achieved in less
than 10 seconds. Once installed, the CNVD 10 is considered simple
to operate, by turning a power switch ON the sight is energized and
the normal sighting features of the RCO (field of view and reticle
pattern) are unchanged. Sight picture is optimized by adjusting an
OFF/ON manual gain control knob as the system is turned ON, or at
any time during operation. The sight picture is focused by
adjusting the range focus lever or knob at the top front portion of
the sight. Designed for maximum flexibility, the range focus lever
may be reached equally well from either side of the CNVD. All user
controls and adjustments should preferably be tactile, provide user
feedback during operation, and be accessible even with arctic
gloves.
[0038] The CNVD 10 may incorporate a compact optical design,
lightweight molded ULTEM plastic, housing 46 and a low profile
mount design, resulting in an exceptionally small system.
[0039] The CNVD 10 also presents a low profile when mounted on the
weapon W, with a minimum of snag hazard which would cause the sight
to tangle in vines, branches, barbed wire, etc, during a
mission.
[0040] A CNVD battery cap 64 is preferably readily accessible with
a gloved hand, and a typical battery can be quickly replaced while
the CNVD 10 is still weapon mounted. A polarity indicator, in the
form of an embossed "plus" symbol may be formed on the exterior of
the housing 46 indicating a correct battery orientation. Reverse
polarity protection may ensure that no damage is caused by
incorrect insertion of the battery. An optional low battery
indicator may further alert the operator when less than 30 minutes
of battery life, for instance, remains.
[0041] The clip-on night viewer device 10 of the present invention
is mountable on a man portable weapon W with a known rail-type of
weapons mount 58 of the type that includes a rail unit 68 mounted
on the man-portable weapon W and a clip on mount unit 66 that is
attachable to the night viewer device 10 to releasably engage with
the complementary rail 68.
[0042] The man portable weapon W has a mounted (fixed or removable)
optical scope 16 aligned with the mounting rail 68 and further
alignable with the bore of the weapon W (the boresight alignment 36
for the weapon being used). The night viewer device 10 is mountable
in an optical path 32 ahead of the optical scope 16 in order that
the optical scope "looks" into the display 28 of the CNVD 10 rather
than directly downrange to the scene 14 to be viewed. Typically,
the CNVD 10 will be releasably mountable in proximity to the
optical sight 16 for light transmission optimization and to reduce
extraneous light from escaping the CNVD 10 alerting an enemy to the
position of the night viewer and user.
[0043] The image enhancing unit 22 of the CNVD 10 generally
includes a known type of image intensifier tube 70 having a housing
72, a typical fiber optic bundle 74, photocathode 76, power supply
78, and output imager 80. The image intensifier 70 is preferably
maintained in a fixed position within the main housing 46 whereas
the focus cell 40 is movable for focusing of the image.
[0044] Typically, the output image display 28 of the CNVD is a
phosphorescent screen developing an image is a common green hue.
Alternatively, the output of the image intensifier tube 70 can be
operationally connected using any known technique to an electronic
display, either for direct viewing or remote viewing as appropriate
and desired while maintaining boresight alignment of the scope and
the weapon. The rear display hood or shield 54 may be used to
reduce the extraneous release of light from the CNVD display.
[0045] The CNVD 10 of the present invention is a rugged
electro-optical system providing night-time engagement capability
to the user eliminating the requirement to remove the Rifle Combat
Optic (RCO), or optical scope 16. The CNVD 10 attaches to the
MIL-STD-1913 rail 68 in front of and in line with the RCO 16,
without any change to the RCO position. It extends the use of the
RCO 16 aiming capability into low light level conditions such as
twilight or night. The CNVD 10 optionally includes the known quick
disconnect (QD) single-throw locking lever type mount 66 to enable
a rapid transition from day-time to night-time engagement modes.
The present CNVD 10 may also be used independently as a hand-held
night vision viewer.
[0046] The CNVD unity power design preserves the normal RCO sight
picture for the user in terms of field of view and reticle
appearance. The RCO 16 zero is maintained when the CNVD 10 is
installed.
[0047] The CNVD 10 may utilize a known MX-11769-type 18 mm high
performance Gen III tube 70 with an autogated power supply 78. This
is the same tube type that has been provided in the AN/PVS-14 night
vision goggle and has been used on the AN/PVS-24 night viewer.
[0048] An optical axis 32 of an optical scope 16 and a night viewer
device 10 can thus be aligned through the steps of: [0049] a.
enhancing an image of a scene to be viewed with an image enhancing
unit 22 for enhancing the image into a desired format; the image to
be enhanced being received by an input end of the image enhancing
unit 26; [0050] b. producing an output image with an output image
display unit 28 for selective viewing of the enhanced image 12;
and, [0051] c. transmitting the enhanced image 12 of the scene 14
to be viewed through a Risley prism unit 30.
[0052] With such a system of the present invention, the optical
axis alignment of the night viewer device is adjusted through
rotation of at least one prism in the Risley prism unit 30a or
30b.
Focus Mechanism for Focus Cell Lens Group
[0053] In another embodiment of the present invention, the
focusable night viewer device 10 is adapted to receive an image to
be enhanced of a viewed or observed scene 14, and, similar to
described above, includes an objective lens assembly 20 for
gathering light forming the image of the scene 14 to be viewed. The
image enhancing unit 22 enhances the image into a desired format as
previously described. The image to be enhanced is received at an
input end 18 of the image enhancing unit 22. An output image
display unit 28 is operably connected with the image enhancing unit
22 for viewing of the enhanced image 12 by a user.
[0054] A focusing assembly 38 is used for controllably moving by a
user a focus lens cell assembly 40 that is mounted between the
objective lens assembly 20 and the image enhancing unit 22 in a
fore and aft direction along a desired central optical axis or
image path 32 through the objective lens assembly 20. Rotational
movement of a user accessible knob assembly 42 about an axis 44
essentially perpendicular to the optical axis 32 is mechanically
translated into rotational movement of the focus cell 40 to move
the focus cell 40 fore and aft relative to the objective lens
assembly 20 along the desired optical path 32 through the objective
lens assembly 20.
[0055] Generally, the central axis 32 through the objective lens 20
and a central axis of the image enhancing unit 22 are aligned and
normally co-axially so aligned.
[0056] The focus cell lens assembly 40 moves along a track system
or guide 96 responsive to a user's control of a rotatable knob 98.
Generally, the focus knob 98 rotates left or right about the
vertical axis 44.
[0057] The focus cell 40 preferably moves being guided by a helical
guide system 100 producing rotational 102 and translational 104
movement of the focus cell 40 relative to the objective lens
assembly 20 along the desired optical axis 32 through the objective
lens assembly 20. The helical guide 100 preferably includes a
threaded segment 106 formed on a portion of the exterior 108 of the
focus cell 40 with a complementary threaded segment 110 mounted in
the interior of the night viewer device 10.
[0058] Optionally, the knob 98 may be tadpole-like shaped having a
central body 112 that is essentially circular or round and an
extended lever portion 114 extending from the central body 112 for
enhanced user control. Such a design permits the user in the field
to rapidly move the knob 98 and thereby quickly achieving improved
focus.
[0059] The rotational movement of the knob 98 may be mechanically
transmitted to a rack segment 116 or mechanism for moving a
complementary spur gear 118 attached to an exterior portion 108 of
the focus cell 40.
[0060] Referring now particularly to FIG. 8, the rack mechanism 116
and knob 98 are shown preferably mounted on the underside 130 of a
removable portion 132 of the housing 46. A slotted bar 134 has a
first end 136 pivotally attached to the housing segment 132 off
center of the axis 44 of rotation for the knob 98. The opposite end
138 of the slotted bar 134 has a rack element or segment 140 with
teeth attached to engage the complementary teeth of the spur gear
118 that is formed about the portion of the movable focus cell
assembly 40 with the orientation of the spur gear 118 being
essentially perpendicular to the central optical axis 32.
[0061] The rack element 140 should be movably affixed to the second
end 138 of the slotted bar 134. A pin 142 is affixed to the
underside of the knob 98 off center of the axis 44 of rotation for
engaging the slot 144.
[0062] The user rotates the knob 98 causing the rack 140 to move at
the end 138 of the pivotally mounted slotted bar 134 translating
the rotational movement of the knob 98 into lateral movement of the
rack 140. The lateral movement of the rack 140 is at the same time
translated into rotational movement of the focus cell 40 as the
teeth of the rack 140 engage the complementary teeth of the spur
gear 118.
[0063] By attaching the knob assembly 42 to the removable portion
of the housing 46 one may first make an initial gross adjustment of
the focus cell 40 with the rack assembly disengaged from the spur
gear 118 to give an approximate focusing position to the focus cell
lens group 40 and then by reattaching the knob assembly 42 and
engaging the rack 140 and spur gear 118 to give fine focusing
control to the user.
[0064] A night viewer device 10 of the type having an objective
lens assembly for gathering light forming the image of the scene to
be viewed, an image enhancing unit 22 for enhancing the image into
a desired format, and, the image to be enhanced received at an
input end 26 of the image enhancing unit 22, can be focused using
the steps of: [0065] controllably moving a focus cell assembly 40
of the image enhancing unit 22 along a desired central optical axis
32 through the objective lens assembly 20 through rotational
movement of a user accessible knob assembly 42 about an axis 44
essentially perpendicular to the central optical axis 32 is
mechanically translated into rotational movement of the locus cell
40 to move the focus cell 40 fore and aft relative to the objective
lens assembly 20 along the desired optical path 32 through the
objective lens assembly 20.
[0066] The foregoing disclosure and description of the invention
are illustrative and explanatory thereof, and various changes in
the size, shape and materials, as well as in the details of the
illustrated construction may be made without departing from the
spirit of the invention.
* * * * *