U.S. patent application number 15/592536 was filed with the patent office on 2018-11-15 for thermal reflex sight.
The applicant listed for this patent is Steiner eOptics, Inc.. Invention is credited to Marc R. HAMMOND, Robert J. KOGUT, Adam PASTERNAK.
Application Number | 20180328694 15/592536 |
Document ID | / |
Family ID | 62167129 |
Filed Date | 2018-11-15 |
United States Patent
Application |
20180328694 |
Kind Code |
A1 |
HAMMOND; Marc R. ; et
al. |
November 15, 2018 |
THERMAL REFLEX SIGHT
Abstract
A reflex sight comprises two apertures. One aperture is a direct
view optical path of the target scene. The other aperture is a
digital (e.g., thermal) camera or image intensifier. A beam
combiner with two reflective surfaces (for example, a Bauernfeind,
Penta, or other prism bonded to a wedge prism) and afocal eyepiece
optics overlay the digital image or intensified image onto the
direct view scene with matched magnification.
Inventors: |
HAMMOND; Marc R.;
(Waitsfield, VT) ; KOGUT; Robert J.; (Waitsfield,
VT) ; PASTERNAK; Adam; (Waitsfield, VT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Steiner eOptics, Inc. |
Waitsfield |
VT |
US |
|
|
Family ID: |
62167129 |
Appl. No.: |
15/592536 |
Filed: |
May 11, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F41G 1/30 20130101; F41G
3/326 20130101; F41G 1/345 20130101; H04N 5/23293 20130101; G03B
13/06 20130101; F41G 1/38 20130101; F41G 3/165 20130101; H04N 5/332
20130101; G02B 23/12 20130101; H04N 5/278 20130101; F41G 1/32
20130101 |
International
Class: |
F41G 1/34 20060101
F41G001/34; H04N 5/33 20060101 H04N005/33; H04N 5/232 20060101
H04N005/232; H04N 5/278 20060101 H04N005/278; G02B 23/12 20060101
G02B023/12; G03B 13/06 20060101 G03B013/06; F41G 3/16 20060101
F41G003/16 |
Goverment Interests
[0001] This invention was made with government support under the
Small Business Innovation Research program via contract number
W909MY-14-C-000 awarded by the U.S. Army Night Vision and
Electronic Systems Directorate. The government has certain rights
in the invention.
Claims
1. An aiming sight comprising: a beam combiner comprising a first
planar outer surface oriented perpendicularly to a first axis, a
second planar outer surface oriented parallel to and oppositely
positioned from the first planar outer surface, an internal coated
planar surface oriented at an acute angle with respect to the first
and second outer planar surfaces, and a third planar outer surface;
either an image intensifier or a display for a digital camera; an
afocal eyepiece; and a first housing comprising the beam combiner,
the image intensifier or display for a digital camera, and the
afocal eyepiece; wherein the housing is adapted to be attached to a
firearm; wherein a first optical path is coaxial with the first
axis and provides a direct view in the visible spectrum straight
through the first and second outer planar surfaces of the beam
combiner of a target scene at which the aiming sight is aimed;
wherein along a second optical path the afocal eyepiece collects
light from the image intensifier or the digital camera display to
produce afocal light rays that are incident on and transmitted
through the third planar outer surface of the beam combiner, then
incident on the first planar outer surface of the beam combiner
from inside the beam combiner at an angle resulting in total
internal reflection of the rays by the first planar outer surface
toward the internal coated planar surface, then reflected by the
internal coated planar surface along the first axis as an afocal
image of the target scene overlaying and magnification matched with
the direct view of the target scene.
2. The aiming sight of claim 1 comprising a digital camera display,
wherein the first housing comprises a digital camera connected to
provide a signal to the digital camera display.
3. The aiming sight of claim 1 comprising a digital camera display,
wherein: a digital camera configured to provide a signal to the
digital camera display is housed in a separate housing adapted for
mounting to the firearm; and the first housing is adapted to be
attached to a firearm telescopic magnifying scope with the direct
view optical path passing through the magnifying scope.
4. The aiming sight of claim 1 comprising an image intensifier.
5. The aiming sight of claim 1, wherein a coating on the internal
coated surface reflects visible light having a wavelength greater
than a cutoff wavelength and transmits light having a wavelength
shorter than a cutoff wavelength, and the light from the image
intensifier or digital camera display has a wavelength greater than
the cutoff wavelength.
6. The aiming sight of claim 1, wherein a coating on the internal
coated surface is a narrow spectral band reflective coating and the
light emitted by the digital camera display or image intensifier is
substantially monochromatic with a center wavelength closely
coinciding with the center wavelength of the narrow band reflective
coating.
7. The aiming sight of claim 1 comprising a digital camera display
connected to receive a signal from a digital camera, wherein the
display is controllable to provide a full image of the target
scene, an outline image of bright portions of the target scene, or
a mixed full and outline image of the target scene.
8. The aiming sight of claim 1 comprising a digital camera display
connected to receive a signal from a digital camera, wherein the
display is controllable to overlay a dot, reticle, crosshair, or
combination thereof with the afocal image and direct view to
provide a reference for where the firearm is aimed.
9. The aiming sight of claim 1 comprising a digital camera display
connected to receive a signal from a digital camera sensitive to
light in the ultraviolet spectral range of about 200 nm to about
400 nm.
10. The aiming sight of claim 1 comprising a digital camera display
connected to receive a signal from a digital camera sensitive to
light in the visible spectral range of about 400 nm to about 700
nm.
11. The aiming sight of claim 1 comprising a digital camera display
connected to receive a signal from a digital camera sensitive to
light in the near infrared spectral range of about 700 nm to about
1100 nm.
12. The aiming sight of claim 1 comprising a digital camera display
connected to receive a signal from a digital camera sensitive to
light in the short wave infrared spectral range of about 1100 nm to
about 3000 nm.
13. The aiming sight of claim 1 comprising a digital camera display
connected to receive a signal from a digital camera sensitive to
light in the mid wave infrared (MWIR) spectral range of about 3000
nm to about 5000 nm.
14. The aiming sight of claim 1 comprising a digital camera display
connected to receive a signal from a digital camera sensitive to
light in long wave infrared (LWIR) spectral range of about 7000 nm
to about 12000 nm.
15. The aiming sight of claim 1 comprising a digital camera
display, wherein: the first housing comprises a digital camera
connected to provide a signal to the digital camera display; and
the display is controllable to provide a full image of the target
scene, an outline image of bright portions of the target scene, or
a mixed full and outline image of the target scene.
16. The aiming sight of claim 15, wherein a coating on the internal
coated surface reflects visible light having a wavelength greater
than a cutoff wavelength and transmits light having a wavelength
shorter than a cutoff wavelength, and the light from the digital
camera display has a wavelength greater than the cutoff
wavelength.
17. The aiming sight of claim 15, wherein a coating on the internal
coated surface is a narrow spectral band reflective coating and the
light emitted by the digital camera display is substantially
monochromatic with a center wavelength closely coinciding with the
center wavelength of the narrow band reflective coating.
18. The aiming sight of claim 15 wherein the digital camera is
sensitive to light in the ultraviolet spectral range of about 200
nm to about 400 nm.
19. The aiming sight of claim 15 wherein the digital camera is
sensitive to light in the visible spectral range of about 400 nm to
about 700 nm.
20. The aiming sight of claim 15 wherein the digital camera is
sensitive to light in the near infrared spectral range of about 700
nm to about 1100 nm.
21. The aiming sight of claim 15 wherein the digital camera is
sensitive to light in the short wave infrared spectral range of
about 1100 nm to about 3000 nm.
22. The aiming sight of claim 15 wherein the digital camera is
sensitive to light in long wave infrared (LWIR) spectral range of
about 7000 nm to about 12000 nm.
23. The aiming sight of claim 15 wherein the digital camera is
sensitive to light in the mid wave infrared (MWIR) spectral range
of about 3000 nm to about 5000 nm.
24. The aiming sight of claim 1 comprising a digital camera
display, wherein: a digital camera configured to provide a signal
to the digital camera display is housed in a separate housing
adapted for mounting to the firearm; the first housing is adapted
to be attached to a firearm telescopic magnifying scope with the
direct view optical path passing through the magnifying scope; and
the display is controllable to provide a full image of the target
scene, an outline image of bright portions of the target scene, or
a mixed full and outline image of the target scene.
25. The aiming sight of claim 24, wherein a coating on the internal
coated surface reflects visible light having a wavelength greater
than a cutoff wavelength and transmits light having a wavelength
shorter than a cutoff wavelength, and the light from the digital
camera display has a wavelength greater than the cutoff
wavelength.
26. The aiming sight of claim 24, wherein a coating on the internal
coated surface is a narrow spectral band reflective coating and the
light emitted by the digital camera display is substantially
monochromatic with a center wavelength closely coinciding with the
center wavelength of the narrow band reflective coating.
27. The aiming sight of claim 24 wherein the digital camera is
sensitive to light in the ultraviolet spectral range of about 200
nm to about 400 nm.
28. The aiming sight of claim 24 wherein the digital camera is
sensitive to light in the visible spectral range of about 400 nm to
about 700 nm.
29. The aiming sight of claim 24 wherein the digital camera is
sensitive to light in the near infrared spectral range of about 700
nm to about 1100 nm.
30. The aiming sight of claim 24 wherein the digital camera is
sensitive to light in the short wave infrared spectral range of
about 1100 nm to about 3000 nm.
31. The aiming sight of claim 24 wherein the digital camera is
sensitive to light in long wave infrared (LWIR) spectral range of
about 7000 nm to about 12000 nm.
32. The aiming sight of claim 24 wherein the digital camera is
sensitive to light in the mid wave infrared (MWIR) spectral range
of about 3000 nm to about 5000 nm.
Description
FIELD OF THE INVENTION
[0002] The invention relates generally to firearm aiming
sights.
BACKGROUND
[0003] Firearm aiming sights may use a thermal imaging camera to
capture a thermal (infrared) image of a target scene and display
the image in visible light on a display viewed by the user in order
to enhance night-time and other low light vision or to detect warm
objects through foliage, camouflage, fog, dust, or other
obscurants. Alternatively, such aiming sights may use an image
intensifier or other high sensitivity camera or imaging system to
amplify low levels of visible light from the target scene or image
other spectral bands of light not detectable by the human eye and
display the resulting images to the operator via a phosphor screen
or other type of display. In either case, it may be advantageous to
superimpose the image from the camera or the intensifier on a
direct view image of the target scene.
SUMMARY
[0004] This specification discloses thermal reflex sights that fuse
(superimpose) an image of a target scene from a thermal or other
digital camera or an image of the target scene from an image
intensifier onto a direct view of the target scene. The reflex
sights comprise two apertures. One aperture is a direct view
optical path of the target scene. The other aperture is the
objective lens for the digital camera or image intensifier. A beam
combiner with two reflective surfaces (for example, a Bauernfeind,
Penta, or other prism bonded to a wedge prism) and an afocal
eyepiece overlay the digital image or intensified image of the
target scene onto the direct view scene with matched magnification.
The digital image can be static or dynamic and can comprise text
and/or symbology and/or video from a thermal (mid or long wave
infrared), short wave infrared, image intensified, near infrared,
ultraviolet, or visible spectrum sensitive camera.
[0005] If the thermal reflex sight comprises a digital camera, the
digital camera may be housed with the camera display and the beam
combiner in a shared housing adapted to be mounted on a firearm.
Alternatively, the camera display and beam combiner may be housed
in a shared housing adapted to be mounted to a firearm, and the
camera may be housed in a separate housing also adapted to be
mounted to the firearm. The housings may mount to the firearm via a
conventional Picatinny rail, for example.
[0006] The thermal reflex sight may operate with unity
magnification. Alternatively, the thermal reflex sight may be
adapted to attach to a magnifying telescopic sight with the direct
view optical path passing through the magnifying scope. In the
latter variation, the camera may be housed separately from the
other components in a housing adapted to be mounted to a
firearm.
[0007] These and other embodiments, features and advantages of the
present invention will become more apparent to those skilled in the
art when taken with reference to the following more detailed
description of the invention in conjunction with the accompanying
drawings that are first briefly described.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows an arrangement of optical components in an
example embodiment of a thermal reflex sight.
[0009] FIGS. 2A-2C show the arrangement of optical components of
FIG. 1 integrated in a shared housing with a camera in an example
embodiment of a thermal reflex sight.
[0010] FIG. 2D shows an example embodiment comprising an image
intensifier rather than a camera but otherwise similar or identical
to the example embodiment shown in FIGS. 2A-2C.
[0011] FIG. 3A shows the arrangement of optical components of FIG.
1 in a housing attached to a magnifying scope with the direct view
optical path through the reflex sight passing through the scope in
another example embodiment of a thermal reflex sight. FIG. 3B shows
a separately housed camera which may be used in combination with
the arrangement shown in FIG. 3A.
[0012] FIGS. 4A-4C show views of a target scene through an example
embodiment of a thermal reflex sight.
DETAILED DESCRIPTION
[0013] The following detailed description should be read with
reference to the drawings, in which identical reference numbers
refer to like elements throughout the different figures. The
drawings, which are not necessarily to scale, depict selective
embodiments and are not intended to limit the scope of the
invention. The detailed description illustrates by way of example,
not by way of limitation, the principles of the invention. This
description will clearly enable one skilled in the art to make and
use the invention, and describes several embodiments, adaptations,
variations, alternatives and uses of the invention, including what
is presently believed to be the best mode of carrying out the
invention.
[0014] As used in this specification and the appended claims, the
singular forms "a," "an," and "the" include plural referents unless
the context clearly indicates otherwise. Also, the term "parallel"
is intended to include "substantially parallel" geometries, that
is, to encompass minor inconsequential deviations from parallel
geometries. The term "perpendicular" is intended to include
substantially perpendicular geometries, that is, to encompass minor
inconsequential deviations from perpendicular geometries. The term
"planar" is intended to include substantially planar geometries,
that is, to encompass minor inconsequential deviations from planar
geometries.
[0015] FIG. 1 shows an arrangement of optical components in one
example of a thermal reflex sight 100. In this example, beam
combiner 110 comprises a planar outer surface 105 oriented
perpendicularly to a first axis 112, a planar outer surface 115
oriented parallel to and oppositely positioned from the planar
outer surface 105, an internal planar surface 120 oriented at an
acute angle with respect to the outer planar surfaces 105 and 115,
and a planar outer surface 125. Internal planar surface 120 is
coated with a partially reflective coating. In this example, the
reflex sight comprises a digital display 130 for a digital camera
(not shown). The reflex sight also comprises an afocal eyepiece
135.
[0016] Still referring to FIG. 1, a first optical path through
reflex sight 100 is coaxial with first axis 112 and provides to a
user (e.g., user eye 113) a direct view in the visible spectrum
straight through outer planar surfaces 105, 115 of the beam
combiner of a target scene at which the aiming sight is aimed.
[0017] Along a second optical path through the reflex sight the
afocal eyepiece 135 collects visible light rays from digital camera
display 130 to produce afocal light rays that are incident on and
transmitted through planar outer surface 125 of the beam combiner.
In the illustrated example, optional mirror 133 reflects the
visible light rays from display 130 to afocal eyepiece 135, but
other arrangements may be used instead if suitable. After passing
through planar outer surface 125 of the beam combiner, the afocal
light rays from the eyepiece are incident on planar outer surface
105 of the beam combiner from inside the beam combiner at an angle
resulting in total internal reflection of the rays by planar outer
surface 105 toward internal coated planar surface 120. The internal
coated planar surface reflects the afocal light rays along the
first axis as an afocal image of the target scene overlaying the
direct view of the target scene with matched magnification. Light
rays from display 130 are thus reflected twice in beam combiner
110, first by total internal reflection at planar outer surface
105, then by partially reflective coated surface 120. This
arrangement allows beam combiner 110 to have an advantageously thin
profile as measured along first axis 112.
[0018] Display 130 may be or comprise, for example, a liquid
crystal display (LCD) or an organic light emitting diode display
(OLED). In an alternative variation of example reflex sight 100,
the reflex sight comprises an image intensifier rather than a
digital camera. In that case display 130 is replaced by a phosphor
screen at the output of the image intensifier.
[0019] The partially reflective coating on internal planar surface
120 allows a portion of the visible spectrum to pass straight
through beam combiner 110 parallel to first axis 112 to provide the
direct view to the user. In addition, the partially reflective
coating reflects a portion of the visible spectrum including
wavelengths of light emitted by display 130 (or alternatively,
emitted by the phosphor screen of an image intensifier) to overlay
the image from the second optical path with the direct view.
[0020] In one variation, the partially reflective coating on
internal planar surface 120 of the beam combiner is a narrow
spectral band reflective coating and the light emitted by display
130 (or the phosphor screen of an image intensifier) is
substantially monochromatic with a center wavelength closely
coinciding with the center wavelength of the narrow band reflective
coating such that the display light or phosphor screen light is
substantially reflected (e.g., greater than or equal to 95%) toward
the user's eye. The narrow band reflective coating on surface 120
is also known as a trichroic coating. Such a coating, for example,
can be designed to reflect a high proportion of light within a
spectral band from 590 to 610 nm while transmitting a high
proportion of visible light with wavelengths less than 590 nm and
greater than 610 nm. This results in high display brightness
reaching the user's eye while retaining high overall light
transmission from the outside through the beam combiner to the
user's eye.
[0021] In another variation, the partially reflective coating on
internal planar surface 120 of the beam combiner is a short pass
coating that is transmissive for visible wavelengths shorter than a
cutoff wavelength and highly reflective for visible wavelengths
longer than the cutoff wavelength. The cutoff wavelength may be,
for example approximately 600 nm, approximately 610 nm,
approximately 630 nm, or approximately 650 nm.
[0022] The partially reflective coating on internal planar surface
120, whether it is a narrow band reflective coating or a short pass
coating, may be selected to be highly reflective for a selected
range of red light wavelengths and transmissive for shorter visible
wavelengths. In such cases transmission of the full visible
spectrum through the coated surface along first axis 112 (in the
direct view) may be greater than or equal to about 85%, for
example. The loss of red light from the direct view optical path as
a result of reflection from coated surface 120 typically does not
significantly degrade the direct view, because red light is less
valuable to human vision than are the shorter visible
wavelengths.
[0023] Beam combiner 110 may be formed, for example, by bonding a
Bauernfeind, Penta, or other prism 110a to a wedge prism 110b along
internal surface (e.g., interface) 120. The presence of wedge prism
110b with outer planar surface 115 parallel to outer planar surface
105 provides an undistorted look-through for the direct view
optical path.
[0024] A digital camera providing a signal to display 130 may be
sensitive to wavelengths in the ultraviolet spectral range of about
200 nm to about 400 nm, the visible spectral range of about 400 nm
to about 700 nm, the near infrared spectral range of about 700 nm
to about 1100 nm, or the short wave infrared spectral range of
about 1100 nm to about 3000 nm. In some variations, the digital
camera detects light in the long wave infrared (LWIR) spectral
range of about 7000 nm to about 12000 nm. In other variations, the
digital camera detects light in the mid wave infrared (MWIR)
spectral range of about 3000 nm to about 5000 nm. Digital cameras
used in the invention may employ focal plane array technologies
including, but not limited to, charge coupled device (CCD),
complementary semiconductor oxide (CMOS), silicon (Si), indium
gallium arsenide (InGaAs), indium antimonide (InSb),
microbolometers, or mercury cadmium telluride (MCT or HgCdTe).
[0025] Display 130 may be or comprise, for example, an
800.times.600, 15 micron pixel, OLED micro-display. Display 130 may
be or comprise, for example, a 640.times.480, 15 micron pixel, LCD
micro-display. Any other suitable digital display may also be
used.
[0026] An image intensifier, if present, may be sensitive to light
in the range of, for example, about 380 nm to about 900 nm.
[0027] In some variations reflex sight 100 may have a field of view
of, for example, about 16 degrees horizontally by about 12 degrees
vertically (about 20 degrees diagonally).
[0028] FIGS. 2A-2C show an example embodiment of thermal reflex
sight 100 comprising a digital camera 150 integrated in a shared
housing 160 with the components shown in FIG. 1. FIG. 2A is a
cross-sectional view showing the internal components. FIG. 2B is a
side view, and FIG. 2C is a perspective view. Camera 150 comprises
an objective lens assembly 153 that collects light along camera
axis 154 and images it onto a focal plane array 155, which provides
a signal representing the image to display 130. Camera axis 154 may
be substantially parallel to first axis 112. Alternatively, camera
axis 154 may intersect axis 112 at a distance from thermal reflex
sight 100.
[0029] Housing 150 may be adapted to mount to a firearm, for
example via Picatinny rail mount 165. User interface controls such
as rotatable knobs 170 and 175 and switches (buttons) 180A-180D may
be used to adjust windage and elevation to align first axis 112 and
camera axis 153 as desired with respect to the firearm on which the
reflex sight is mounted and control the camera and/or camera
display (or alternatively, an image intensifier if present). In
some variations windage and elevation (more generally, bore sight
alignment) adjustments may be made electronically by shifting the
position on display 130 at which the image from camera 150 is
displayed.
[0030] In the example illustrated in FIGS. 2A-2C, thermal reflex
sight 100 is about 115 mm, about 40 mm wide, and about 40 mm tall,
with a direct view aperture of about 30 mm. Any other suitable
dimensions may also be used.
[0031] FIG. 2D shows a cross-sectional view of an example
embodiment of thermal reflex sight 100 comprising an image
intensifier 151 (rather than a camera) integrated in a shared
housing 160 with the components shown in FIG. 1. In this example
objective lens assembly 153 collects light along image intensifier
axis 154 and focuses it into image intensifier 151, which displays
an intensified image on phosphor screen 131. Light rays from
phosphor screen 131 are directed onto mirror 133 by prism 132, and
thence through afocal eyepiece 135 and beam combiner 110. Apart
from use of an image intensifier rather than a camera and minor
changes to the optical paths (e.g., use of prism 132) to
accommodate that change, the structure and operation of this
embodiment of reflex sight 100 is similar or identical to that
described above with respect to FIGS. 2A-2C.
[0032] FIG. 3A shows an example embodiment of thermal reflex sight
100 in which the components shown in FIG. 1 are housed in a housing
185 adapted to attach (e.g., clip on) to a magnifying telescopic
sight 190 with the direct view optical path through the reflex
sight passing through the magnifying scope. In FIG. 3A reflex sight
100 is shown in cross-section, and magnifying scope 190 is shown in
a corresponding side view. Scope 190 may provide a magnification
of, for example, 1.times. to 5.times.. FIG. 3B shows a
cross-sectional view of camera 150 housed separately from the
components shown in FIG. 1 in a housing 195, which may be attached
for example to a side rail on a firearm to which magnifying scope
190 is mounted with camera axis 154 parallel to first axis 112, or
with camera axis 154 intersecting first axis 112 at some
distance.
[0033] In some variations, display 130 in thermal reflex sight 100
may be operated to present, for example, a low intensity image of
the target scene, a full (e.g., thermal) image of the target scene,
an outline image of (e.g., thermally) bright portions of the target
scene, a mixed outline/low intensity image, or no image. Reflex
sight 100 may be switched between these modes using buttons
180A-180D, for example. As examples of several of these modes, FIG.
4A shows a direct view of a target scene (a person standing at the
edge of a forest) without a fused (e.g., thermal) image, FIG. 4B
shows an outline image of the same target scene fused with the
direct view, and FIG. 4C shows a full (e.g., thermal) image of the
target scene fused with the direct view. Display 130 may also be
operated to present a red dot, reticle, crosshair, or combination
thereof in the fused image to provide a reference for where the
firearm is aimed.
[0034] Although reflex sight 100 is referred to herein as a
"thermal" reflex sight, the term thermal is not meant to be
limiting. Camera 150, or an image intensifier used in its place,
may be selected to be sensitive to visible wavelengths of light or
to wavelengths of light outside human vision other than, or in
addition to, thermal infrared wavelengths. In such cases, display
130, or the phosphor screen of an image intensifier, presents an
image based at least in part on light collected at those other
non-thermal wavelengths.
[0035] This disclosure is illustrative and not limiting. Further
modifications will be apparent to one skilled in the art in light
of this disclosure and are intended to fall within the scope of the
appended claims.
* * * * *