U.S. patent number RE33,572 [Application Number 07/379,271] was granted by the patent office on 1991-04-16 for invisible light beam projector and night vision system.
Invention is credited to Brad E. Meyers.
United States Patent |
RE33,572 |
Meyers |
April 16, 1991 |
**Please see images for:
( Certificate of Correction ) ** |
Invisible light beam projector and night vision system
Abstract
A relatively large diameter, sharply focused beam of invisible
light is produced by a projector (10) for the purpose of lighting
up a person, object, etc. to be viewed at night. The projector (10)
is used in conjunction with a night vision telescope (12) which
includes a light intensifier (88). The projector (10) includes a
pulsating infrared LED, or a laser diode, adapted to produce a high
intensity narrow beam of invisible light. This beam of invisible
light is enlarged by a projection lens assembly (26) adapted to
sharply focus the light into a collimated light beam of about the
diameter of the projector housing (20). The light source (30) is
pulsed on and off, and is on only about 10-20% of the time. When on
it is illuminated by a high level current which would quickly burn
out the light (30) if operated continuously. The intermittent
operation of the light (30) at high current produces a
nonflickering high intensity light beam. The projection lens (26)
enlarges this beam and clearly focuses it, to produce a relatively
large illuminating beam having a substantially large range of
use.
Inventors: |
Meyers; Brad E. (Redmond,
WA) |
Family
ID: |
27357355 |
Appl.
No.: |
07/379,271 |
Filed: |
July 13, 1989 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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694444 |
Jan 30, 1985 |
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Reissue of: |
003253 |
Dec 29, 1986 |
04707595 |
Nov 17, 1987 |
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Current U.S.
Class: |
250/504R;
250/333; 359/356 |
Current CPC
Class: |
G02B
23/12 (20130101) |
Current International
Class: |
G02B
23/12 (20060101); G02B 23/00 (20060101); G01J
001/00 () |
Field of
Search: |
;250/54R,54H,453.1,333,292.1 ;315/2A ;362/183 ;350/1.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Anderson; Bruce C.
Attorney, Agent or Firm: Hughes & Multer
Parent Case Text
.Iadd.REFERENCE TO RELATED PATENT
This application is an application to reissue U.S. Pat. No.
4,707,585 issued Nov. 17, 1987 to Brad E. Meyers for INVISIBLE
LIGHT BEAM PROJECTOR AND NIGHT VISION SYSTEM. That Letters Patent
matured from application 003,253 filed Dec. 29, 1986. Application
No. 003,253 is a continuation of application No. 694,444 filed Jan.
30, 1985 (now abandoned). .Iaddend.
This is a continuation of application Ser. No. 696,444, filed Jan.
30, 1985, abandoned.
Claims
What is claimed is:
1. An invisible light beam projector, comprising: a tubular body
having a forward end and a rearward end;
an invisible light beam emitting diode having an emitting lens;
mounting means inside of said tubular body mounting the diode at a
location within the body, between the two ends of the body, with
the lens of the diode directed towards the forward end of the
body;
control circuit means for .Iadd.causing .Iaddend.the diode
.[.adapted.]. to be repetitiously charged and discharged, and on
each discharge causing the diode to light and transmit a narrow
beam of invisible light through the emitting lens towards the
forward end of the tubular body.Iadd., .Iaddend.said control
circuit means functioning to turn the diode on and off at a rate
resulting in the diode being on between about 10-20% of the time
and off during the remainder of the time, and when on being powered
by a current that is substantially larger than the diode could
stand if on continuously; and
projection lens means within the tubular body, forwardly of the
diode, of a type which is always in focus in a range between a
predetermined minimum distance from the light projector and
infinity, said projection lens means being positioned and adapted
to receive the narrow beam of invisible light from the diode lens
and enlarge and collimate this light into a collimated beam of
invisible light in sharp focus, to produce a lighting spot having a
sharp and definite edge.
2. An invisible light projector according to claim 1, comprising a
tubular carrier within said tubular body, said mounting means being
in the form of an end wall at an end of the tubular carrier.
3. An invisible light projector according to claim 2, wherein said
control circuit means is housed within the tubular carrier.
4. An invisible light projector according to claim 3, wherein said
control circuit means comprises a circuit board which extends
diametrically within the tubular carrier.
5. An invisible light projector according to claim 1, wherein said
circuit means is located within said tubular body between the
rearward end of the body and the mounting means for the diode,
control switch means for turning the control circuit means on and
off, located outside of said tubular body, and conductor means
connecting the control switch to the control circuit means.
6. An invisible light projector according to claim 5, wherein the
tubular body includes an end wall at the rearward end of the
tubular body, and said conductor means comprises a two component
connector, one of said components being mounted on the end
wall.
7. An invisible light projector according to claim 1, wherein said
control circuit means comprises battery means located within said
tubular body between the rearward end of the body and the mounting
means for the diode.
8. An invisible light projector according to claim 7, wherein said
control circuit means also comprises a circuit board which extends
diametrically within the tubular body, and wherein the battery
means is positioned radially outwardly from the circuit board.
9. An invisible light projector according to claim 1, comprising a
tubular carrier within said tubular body, and wherein said control
circuit means is housed within the tubular carrier and the control
circuit means includes battery means.
10. An invisible light projector according to claim 9, wherein said
control circuit means comprises a circuit board which extends
diametrically within the tubular carrier and the battery means is
positioned radially outwardly of the circuit board.
11. An invisible light projector according to claim 1, wherein the
projection lens means comprises a periscopic lens mounted within
the tubular body towards the forward end of the tubular body, and a
meniscus lens mounted within the tubular body substantially
immediately rearwardly of the periscopic lens, said meniscus lens
being smaller in diameter than said periscopic lens.
12. An invisible light projector according to claim 11, wherein the
lens on the LED is a simple meniscus lens.
13. An invisible light projector according to claim 12, comprising
a tubular carrier within said tubular body, adjacent the rearward
end of the tubular body, said mounting means being in the form of
an end wall at the inner end of the tubular carrier, and wherein
the control circuit means is housed within the tubular carrier,
between said mounting means and the rearward end of the tubular
body.
14. An invisible light projector according to claim 1, wherein the
control circuit means comprises battery means for producing a
current, transistor means between the battery means and the diode,
and integrated circuit means including a capacitor for triggering
the transistor means, so that the transistor means functions as a
switch to ultimately transmit and interrupt current flow from the
battery means to the diode.
15. An invisible light projector according to claim 1, wherein the
diode is an infrared LED.
16. An invisible light projector according to claim 1, wherein the
diode is a laser diode.
17. A night vision system comprising:
an invisible light beam projector comprising:
a tubular body having a forward end and a rearward end;
an invisible light beam emitting diode having an emitting lens;
mounting means inside of said tubular body mounting the diode at a
location within the body, between the two ends of the body, with
the lens of the diode directed towards the forward end of the
body;
control circuit means for .Iadd.causing .Iaddend.the diode
.[.adapted.]. to be repetitiously charged and discharged, and on
each discharge causing the diode to light and transmit a narrow
beam of invisible light through the emitting lens toward the
forward end of the tubular body.Iadd., .Iaddend.said control
circuit means functioning to turn the diode on and off at a rate
resulting in the diode being on between about 10-20% of the time
and off during the remainder of the time, and when on being powered
by a current that is substantially larger than the diode could
stand if on continuously; and
projection lens means within the tubular body, forwardly of the
diode, of a type which is always in focus in a range between a
predetermined minimum distance from the light projector and
infinity, said projection lens means being positioned to receive
the narrow beam of invisible light from the diode lens and
collimate and focus this light into a collimated, sharp focused
beam of invisible light, to produce a lighting spot having a sharp
and definite edge; and
a night vision telescope positioned adjacent to said invisible
light projector and comprising an objective lens, and an image
intensifier means positioned to receive an optical image from the
objective lens, said telescope having a line of sight that is
substantially parallel to the beam of invisible light.
18. A night vision system according to claim 17, comprising a
tubular carrier within said tubular body, said mounting means being
in the form of an end wall at an end of the tubular carrier.
19. A night vision system according to claim 18, wherein said
control circuit means is housed within the tubular carrier.
20. A night vision system according to claim 19, wherein said
control circuit means comprises a circuit board which extends
diametrically within the tubular carrier.
21. A night vision system according to claim 17, wherein said
circuit means is located within said tubular body between the
rearward end of the body and the mounting means for the diode,
control switch means for turning the control circuit means on and
off, located outside of said tubular body, and conductor means
connecting the control switch to the control circuit means.
22. A night vision system according to claim 21, wherein the
tubular body includes an end wall at the rearward end of the
tubular body, and said conductor means comprises a two component
connector, one of said components being mounted on the end
wall.
23. A night vision system according to claim 17, wherein said
control circuit means comprises battery means located within said
tubular body between the rearward end of the body and the mounting
means for the diode.
24. A night vision system according to claim 23, wherein said
control circuit means also comprises a circuit board which extends
diametrically within the tubular body, and wherein the battery
means is positioned radially outwardly from the circuit board.
25. A night vision system according to claim 17, comprising a
tubular carrier within said tubular body, and wherein said control
circuit means is housed within the tubular carrier and the control
circuit means includes battery means.
26. A night vision system according to claim 25, wherein said
control circuit means comprises a circuit board which extends
diametrically within the tubular carrier and the battery means is
positioned radially outwardly of the circuit board.
27. A night vision system according to claim 17, wherein the
projection lens means comprises a periscopic lens mounted within
the tubular body towards the forward end of the tubular body, and a
meniscus lens mounted within the tubular body substantially
immediately rearwardly of the periscopic lens.
28. A night vision system according to claim 27, wherein the lens
on the LED is a simple meniscus lens.
29. A night vision system according to claim 28, comprising a
tubular carrier within said tubular body, adjacent the rearward end
of the tubular body, said mounting means being in the form of an
end wall at the inner end of the tubular carrier, and wherein the
control circuit means is housed within the tubular carrier, between
said mounting means and the rearward end of the tubular body.
30. A night vision system according to claim 17, wherein the
control circuit means comprises battery means for producing a
current, transistor means between the battery means and the diode,
and integrated circuit means including a capacitor for triggering
the transistor means, so that the transistor means functions as a
switch to ultimately transmit and interrupt current flow from the
battery means to the diode.
31. A night vision system according to claim 17, wherein the diode
is an infrared LED.
32. A night vision system according to claim 17, wherein the diode
is a laser diode.
33. An invisible light beam projector, comprising:
a tubular body having a forward end, a rearward end and a center
axis;
a single invisible light beam emitting diode having an emitting
lens;
mounting means inside of said tubular body mounting the diode at a
location within the body, between the two ends of the body, with
the lens of the diode on said center axis, directed towards the
forward end of the body;
control circuit means for .Iadd.causing .Iaddend.the diode
.[.adapted.]. to be repetitiously charged and discharged, and on
each discharge causing the diode to light and transmit a narrow
beam of invisible light through the emitting lens towards the
forward end of the tubular body.Iadd., .Iaddend.said control
circuit means functioning to turn the diode on less than it is off,
and when on being powered by a current that is substantially larger
than the diode could stand if on continuously; and
projection lens means within the tubular body, forwardly of the
diode, of a type which is always in focus in a range between a
predetermined minimum distance from the light projector and
infinity, said projection lens means being positioned and adapted
to receive the narrow beam of invisible light from the diode lens
and enlarge and collimate this light into a collimated beam of
invisible light in sharp focus, to produce a lighting spot having a
sharp and definite edge.
34. A night vision system, comprising:
an invisible light beam projector comprising:
a tubular body having a forward end, a rearward end and a center
axis;
a single invisible light beam emitting diode having an emitting
lens;
mounting means inside of said tubular body mounting the diode at a
location within the body, between the two ends of the body, with
the lens of the diode on said center axis directed towards the
forward end of the body;
control circuit means for .Iadd.causing .Iaddend.the diode
.[.adapted.]. to be repetitiously charged and discharged, and on
each discharge causing the diode to light and transmit a narrow
beam of invisible light through the emitting lens towards the
forward end of the tubular body.Iadd., .Iaddend.said control
circuit means functioning to turn the diode on less than it is off,
and when on being powered by a current that is substantially larger
than the diode could stand if on continuously; and
projection lens means within the tubular body, forwardly of the
diode, of a type which is always in focus in a range between a
predetermined minimum distance from the light projector and
infinity, said projection lens means being positioned to receive
the narrow beam of invisible light from the diode lens and
collimate and focus this light into a collimated, sharp focused
beam of invisible light, to produce a lighting spot having a sharp
and definite edge; and
a night vision telescope positioned adjacent to said invisible
light projector and comprising an objective lens, and an image
intensifier means positioned to receive an optical image from the
objective lens, said telescope having a line of sight that is
substantially parallel to the beam of invisible light. .Iadd.35. A
device for illuminating a target with a beam of radiation in an
invisible portion of the electromagnetic spectrum to enhance the
quality of an image of a target produced by a passive visible light
intensifier and image enhancer, said device comprising: a housing;
a source of said electromagnetic radiation in said housing; and a
lens system in said housing and aligned with said source for
forming the energy emitted from said source into a beam with a well
defined peripheral edge. .Iaddend. .Iadd.36. A device for
illuminating a target as defined in claim 35 in which said lens
system includes a meniscus lens and a periscopic lens assembly
aligned with, spaced from, and on the downstream side of said
meniscus lens, said meniscus lens being sufficiently smaller in
diameter than said periscopic lens assembly to enable said lens
system to produce a beam of electromagnetic energy with a well
defined peripheral edge as aforesaid. .Iaddend. .Iadd.37. A device
for illuminating a target as defined in claim 35 which has: an
elongated casing housing said source of electromagnetic radiation
and said lens system in an optically aligned, spaced apart
relationship; a power source for said electromagnetic radiation
source housed in said tubular casing; and means for controlling the
operation of said source of electromagnetic radiation, said control
means including an operator manipulatable switch which is
accessible from the exterior of said casing. .Iaddend. .Iadd.38. A
system for enhancing the visibility of a target under low light
level conditions, said system comprising: a passive visible light
intensifier and image enhancer capable of providing a visible image
of the target without illumination of the target at levels of light
which are too low for wanted details of the target to be
discernible to the naked eye; a device for illuminating only a
selected area of the target with a focused beam of electromagnetic
radiation which has a well defined peripheral edge and is invisible
to the naked eye but is usable by said image enhancer to provide an
ostensibly continuous image of the selected area of the target that
appears brighter to a user of the system than the rest of the
target in the field of view of the image enhancer; and
operator-engageable switch means for so activating said device that
said system can be employed in a first mode with the target
illuminating device inactivated to provide an image of the target
obtained by the intensification of visible light falling on the
target and in a second mode with said device activated to provide
an image of said target as aforesaid with an enhanced view of that
selected area of the target illuminated by the beam of
invisible
electromagnetic radiation projected from said device. .Iaddend.
.Iadd.39. A system as defined in claim 38 in which the device for
illuminating the target also includes: an elongated casing housing
said source of electromagnetic radiation and said lens system in an
optically aligned, spaced apart relationship; a power source for
said electromagnetic radiation source housed in said tubular
casing; and means for controlling the operation of said source of
electromagnetic radiation, said control means including an operator
manipulatable switch which is accessible from
the exterior of said casing. .Iaddend. .Iadd.40. A system for
enhancing the visibility of a target under low light level
conditions, said system comprising: a passive visible light
intensifier and image enhancer capable of providing a visible image
of the target without illumination of the target at levels of light
which are too low for wanted details of the target to be
discernible to the naked eye and a selectively activatable device
for illuminating only a selected area of the target with a beam of
electromagnetic radiation which is invisible to the naked eye but
is usable by said image enhancer to provide an obtensibly
continuous image of the selected area of the target that appears
brighter to a user of the system than the rest of the target in the
field of view of the image enhancer, whereby said system can be
employed in a first mode with the target illuminating device
inactivated to provide an image of the target obtained by the
intensification of visible light falling on the target and in a
second mode with said device activated to provide an image of said
target as aforesaid with an enhanced view of that selected area of
the target illuminated by the beam of electromagnetic radiation
projected from said device, the device for illuminating the target
with a beam of electromagnetic radiation to enhance the quality of
the selected area of the image comprising: a housing, a source of
said electromagnetic radiation in said housing, and a lens system
in said housing and aligned with said source for forming the energy
emitted from said source into a beam with a well defined peripheral
edge. .Iaddend. .Iadd.41. A system as defined in claim 40 in which
the lens system of the device for illuminating the target with a
beam of electromagnetic radiation includes a meniscus lens and a
periscopic lens assembly aligned with, spaced from, and on the
downstream side of said meniscus lens, said meniscus lens being
sufficiently smaller in diameter than said periscopic lens assembly
to enable said lens system to produce a beam of electromagnetic
energy with a
well defined peripheral edge as aforesaid. .Iaddend. .Iadd.42. A
hand held system for enhancing the visibility of a target under low
light level conditions, said system comprising: an elongated casing
housing a passive, visible light intensifier and image enhancer; a
device fixed to and extending in the same direction as said casing
for illuminating only a related area of said target with a beam of
electromagnetic which is invisible to the naked eye; a handle for
supporting said image enhancer casing, said target illuminating
device including an electrically powered electromagnetic radiation
source and means for forming the energy emitted from said source
into a beam with a well defined peripheral edge and said system
further comprising operator-controllable means which enables said
system to be employed in a first mode with the target illuminating
device inactivated to provide an image of the target obtained by
the intensification of visible light falling on the target and in a
second mode with said device activated to provide an image of said
target as aforesaid with an enhanced view of that selected area of
the target illuminated by the beam of electromagnetic radiation
projected from said device, said target illuminating device further
comprising an electrical control circuit for activating and
deactivating said source and said operator-controllable means
comprising a switch for controlling the source activating and
deactivating operation of said circuit and a trigger means
supported from and accessible from the exterior of the handle which
is displaceable by a user of the system to open and close said
switch.
.Iaddend. .Iadd.43. A system as defined in claim 42 in which the
device for illuminating the target also includes: an elongated
casing housing said source of electromagnetic radiation and a lens
system in an optically aligned, spaced apart relationship; a power
supply source for said electromagnetic radiation source housed in
said tubular casing; and means for controlling the operation of
said source of electromagnetic radiation by connecting said
electromagnetic radiation source to said power supply, said control
means including an operator manipulatable switch which is
accessible from the exterior of said casing. .Iaddend. .Iadd.44. A
system as defined in claim 43 which includes means so operatively
connecting said device-associated switch and said handle-associated
switch to the remainder of the control means of said device that
either of said switches can be closed to turn on the source of
electromagnetic radiation.
.Iaddend. .Iadd.45. A hand held system for enhancing the visibility
of a target under low light level conditions, said system
comprising: an elongated casing housing a passive, visible light
intensifier and image enhancer; a device fixed to and extending in
the same direction as said casing for illuminating only a related
area of said target with a beam of electromagnetic radiation which
is invisible to the naked eye; a handle for supporting said image
enhancer casing, said target illuminating device including an
electrically powered electromagnetic radiation emitter, an
electrical control circuit for activating and deactivating said
source, a housing, a source of said electromagnetic radiation in
said housing, and a lens system in said housing and aligned with
said source for forming the energy emitted from said source into a
beam with a well defined peripheral edge, and said system further
comprising a switch for controlling the source activating and
deactivating operation of said electrical control circuit and a
trigger means supported from and accessible from the exterior of
the handle which is displaceable by a user of the system to open
and close said switch. .Iaddend. .Iadd.46. A system as defined in
claim 44 in which the lens system of the device for illuminating
the target with a beam of electromagnetic radiation includes a
meniscus lens and a periscopic lens assembly aligned with, spaced
from, and on the downstream side of said meniscus lens, said
meniscus lens being sufficiently smaller in diameter than said
periscopic lens assembly to enable said lens system to produce a
beam of electromagnetic energy with a well defined edge as
aforesaid. .Iaddend.
Description
TECHNICAL FIELD
This invention relates to the provision of an invisible light beam
projector and to a night vision system of which the projector is a
part.
BACKGROUND ART
Heretofore, the term "night vision" has been associated with
telescope type devices which, by use of an image intensifier, take
the small amount of light which exists at night and .[.produces.].
.Iadd.produce .Iaddend.from it an image which can be viewed by the
eye or recorded on film.
An early form of night vision device is disclosed by U.S. Pat. No.
1,936,514, granted Nov. 21, 1933, to Thomas C. Lengnick. This
patent discloses using an infrared converter with a search light.
The infrared image tube converts an infrared image of an object,
normally invisible to the human eye, into an image on a glass
screen. This infrared converter was the predecessor of modern day
image intensifiers.
A state-of-the-art image intensifier is quite well described in
U.S. Pat. No. 4,417,814, granted Nov. 29, 1983, to Darrel Doliber.
This patent discloses combining with an image intensifier a device
for sending an aiming dot out of the object being viewed. Light
produced by a light emitting diode (LED) is sharply focused through
either an optical fiber or an aperture, measuring somewhere between
0.0003 .[.to.]. .Iadd.and .Iaddend.0.010 inch in diameter. The
light beam that is produced is seen by the viewer in the form of a
small, bright, high color contrast, red aiming point against a
yellow-green image of the viewed scene. Devices of this type,
involving an aiming dot producing projector in combination with a
light intensifier type night viewer, are available from a number of
different sources.
U.S. Pat. No. 3,752,983, granted Aug. 14, 1973, to Serge J.
Yanez.Iadd., .Iaddend.discloses combining together an infrared
light source, an image intensifier and a camera. The light source
comprises a thirty watt electrical light bulb mounted within a
reflector and an infrared filter positioned forwardly of the light
bulb and reflector.
Other systems which are known at least in the patent literature,
and which should be considered together with the above discussed
known devices, for the purpose of putting the subject invention
into proper perspective relative to the prior art, are disclosed by
the following U.S. patents: U.S. Pat. Nos. 1,969,852, granted Aug.
14, 1934, to Frank J. Markosek; 3,509,344, granted Apr. 28, 1970,
to Albert Bouwers; 3,781,560, granted Dec. 25, 1973, to Raymond J.
DeBurgh and Harold L. Novick; 3,787,693, granted Jan. 22, 1974, to
Robert L. Stone; 3,833,805, granted Sept. 3, 1974, to Charles S.
Naiman, E. P. Chicklis and Arthur Linz; 3,989,947, granted Nov. 2,
1976, to Arthur S. Chapman; 4,040,744, granted Aug. 9, 1977, to
Charles W. Schertz and Edward H. Ritter; 4,112,300, granted Sept.
5, 1978, to Freeman F. Hall and Jerome J. Redmann; 4,226,529,
granted Oct. 7, 1980, to Herbert A. French; 4,290,043, granted
Sept. 15, 1981, to Irwin M. Kaplan; 4,315,150, granted Feb. 9,
1982, to Richard F. Darringer, Wayne L. Scharf and James S.
Haggerty and 4,376,889, granted Mar. 15, 1983, to David W.
Swift.
There is a need for a projector that is capable of projecting, for
a considerable distance, a substantial amount of light energy which
is invisible to the eye, for illuminating a person or object under
surveillance in the dark, for the purpose of brightening the
yellow-green image seen by use of an image intensifier up to where
a face can be identified and a license plate, or the like, can be
read. It is also necessary that the light projector be small in
size, be durable in construction, and be relatively inexpensive to
manufacture. It is the principal object of the present invention to
provide a night light projector which meets this criteria.
DISCLOSURE OF THE INVENTION
The term "invisible light" is used herein to mean light energy
which is normally invisible to the human eye, including infrared
and near infrared light.
An invisible light projector of the present invention is basically
characterized by a tubular body, an invisible light beam emitting
diode within the body, rearwardly of a projection lens means, and a
control circut means for the diode adapted to be repetitiously
charged and discharged, and on each discharge .[.causing1/2
.Iadd.cause .Iaddend.the diode to light and transmit a narrow beam
of invisible light to and through the projection lens means. The
projection lens means is of a type which is always in focus in a
range between a predetermined minimum distance from the light
projector and infinity. It is positioned and adapted to receive the
narrow beam of invisible light from the diode and enlarge and
collimate this light into an enlarged beam of invisible light in
sharp focus.
In accordance with an aspect of the invention, the control circuit
means is adapted to turn the diode on and off at a rate resulting
in the diode being on between about 10-20% of the time and off
during the remainder of the time, and when on being powered by a
current that is substantially larger than the diode could stand if
on continuously.
In accordance with another aspect of the invention, the entire
projector is housed within a relatively short (e.g. about ten
inches) relatively small diameter (e.g. about one and seven-eighths
inch) tubular housing. The invisible light emitting diode is
mounted at an intermediate position within the housing and the
control circuit means is located within the housing between the
diode and the rear end of the housing.
In accordance with yet another .[.respect.]. .Iadd.aspect
.Iaddend.of the invention, the invisible light projector is mounted
onto a tubular body of a night vision telescope which includes an
image intensifier and which is itself mounted onto a pistol grip
type handle having a trigger switch. The trigger switch is
connected to turn on the invisible light projector whenever the
switch is depressed.
The invention also involves various other details of construction
and arrangements of components, as set forth in the description of
the best mode, and as particularly pointed out and distinctly
claimed in the claims .
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings like reference numerals are used to designate like
parts throughout the several views, and:
FIG. 1 is a side elevational view of a night vision system of the
present invention, showing an invisible light projector of the
present invention mounted onto the body portion of a night vision
telescope;
FIG. 2 is a longitudinal sectional view of the invisible light
projector, with some of the detail of the control circuit means
omitted;
FIG. 3 is a cross-sectional view, taken substantially along line
3--3 of FIG. 2, showing the arrangement of the circuit board and
batteries within a tubular carrier within the tubular housing of
the invisible light projector;
FIG. 4 is an end elevational view looking towards the rear end of
the invisible light projector; and
FIG. 5 is a schematic diagram of a control circuit means for the
invisible light emitting diode.
BEST MODES FOR CARRYING OUT THE INVENTION
The embodiment shown in FIG. 1 comprises an invisible light
projector 10 mounted adjacent to a night viewing telescope 12. The
telescope 12 may be mounted onto a pistol grip type handle 14 and
the invisible light projector 10 may be in turn mounted onto the
housing of a telescope 12.
In the preferred embodiment, the pistol grip handle 14 includes a
control trigger 16 which is connected to a control circuit for the
invisible light projector, to be hereinafter .[.be.]. described in
detail. In this embodiment, the user holds the system in one hand,
by gripping the pistol grip 14, and looks into the telescope 12
through the eyepiece 18. He then squeezes the trigger 16 to turn on
the light projector.
Referring to FIG. 2, the invisible light projector 10 is shown to
comprise an elongated tubular body 20 having a forward end 22 and a
rearward end 24. By way of typical, and therefore nonlimitive
example, the tubular body 20 may measure about ten inches in length
and about one and seven-eights inches in outside diameter. Tubular
body 20 may be constructed from a structural plastic material or
from a thin wall metal tubing, for example.
In accordance with the invention, a projection lens assembly 26 is
mounted in a forward portion of the tube. The lens assembly 26 may
be positioned back inside the tubular body 20 a short distance so
as to provide a length of tubing 28 forwardly of the lens assembly
26 which functions as a sun shade.
Also in accordance with the invention, an invisible light emitting
diode 30 is positioned rearwardly and centrally of the lens
assembly 26. Diode 30 includes a forward end positioned lens 32
which is a part of the diode 30. The lens is a simple meniscus
lens, or its equivalent.
Diode 30 may be an infrared LED or an infrared laser diode.
The lens assembly 26 is constructed to be capable of projecting a
sharp or in focus image. The lens assembly 26 is selected to be in
focus throughout a range starting with a predetermined minimum
distance from the projector 10 (e.g. twenty-five feet) out to
infinity.
The diode 30 emits a relatively small diameter beam of invisible
light, which may be no more than about one-fourth of an inch in
diameter. This beam of light is magnified and brought into sharp
focus by the lens assembly 26. The lens assembly 26 sends a sharp
focus beam of light out from the tubular housing 20 which, as it
leaves the tubular housing 20, is substantially the diameter of the
inside of the tubular housing 20 and stays in the form of a sharp
focused, collimated beam throughout the full distance of its
use.
It is important that the lens assembly be capable of transmitting a
sharp image, so that the projected beam will not diverge an
appreciable amount. In other words, the lens assembly 26 is of a
type which first enlarges the small diameter beam from the diode 30
and then collimates the light into a beam of about the diameter of
the tubular body 20. This results in the projected beam having a
substantially long range of use.
The illustrated lens assembly 26 comprises a periscopic lens 34
positioned forwardly of a meniscus lens 36. The lens 36 is smaller
in diameter than the lens 34 and is surrounded by a mounting ring
38. This arrangement results in a spot lighting .[.affect.].
.Iadd.effect.Iaddend.. In other words, the light beam emitting from
the tubular body 20 has relatively sharp and definite edges. If the
lens 36 were to be constructed to be equal in diameter to lens 34,
the beam would have the effect of an intense center beam with a
fuzzy boundary.
In accordance with an aspect of the invention, the diode 30 is
pulsed on and off and when on receives an amperage which would
quickly burn .[.it.]. out the diode 30 if the amperage were to be
continuous. By way of example, two amps of current can be delivered
to the diode 30 at a pulse frequency of about 60-100 cycles per
second, regulated to that of the LED 30 is on only a small
percentage of the time (e.g. 10-20%) and off the remainder of the
time. This manner of operation results in it being possible to
obtain a high intensity light from a relatively small diode 30
without a rapid .[.burn out.]. .Iadd.burnout .Iaddend.of the diode
30.
In preferred form, a tubular carrier 40 is located inside of the
tubular body 20. Tubular carrier 40 has an inner end 42 and an
outer end 44. An end wall 46 is provided at the inner end 42. Wall
46 includes a central opening through which the diode 30 projects,
with the lens 32 of the diode 30 directed towards the projection
lens assembly 26.[.,.]. .Iadd.and .Iaddend.along the center axis of
the lens assembly 26. Thus, in the preferred embodiment, the wall
46 functions as a mounting means for the diode 30. Wall .[.24.].
.Iadd.46 .Iaddend.need not close the entire end of tube 40, but
rather can be in the form of a narrow strip extending across the
diameter of tube 40.
In preferred form, the control circuit means for the diode 30
includes a circuit board 48 which is of a width substantially equal
to the inside diameter of carrier tube 40, so that the circuit
board 48 can be slipped endwise in the tubular carrier 40 and
.Iadd.so .Iaddend.it will extend substantially diametrically of the
tube 40 and will be held in this position by virtue of its side
edges contacting sidewall portions of the tube 40.
In preferred form, the rearward end 24 of the tubular body 20 is
closed by a cap 50. As shown by FIG. 4, cap .[.46.]. .Iadd.50
.Iaddend.may serve as a mount for an off/on switch 52, a receptacle
54 for an AC charger plug.[.,.]. 56 and a receptacle 58 for a plug
60 at the end of a cord 62 (FIG. 1) leading from the trigger switch
16. The plug is schematically shown in FIG. 5 and is designated 60
in that figure.
Referring to FIG. 5, the control circuit means for the diode 30
.[.comprises.]. .Iadd.is powered by .Iaddend.a set of batteries 64.
The battery set 64 may consist of four 1.5 volt rechargeable
alkaline or nickel-cadmium batteries 66 of cylindrical form
measuring about 1.9 inches in length by about 0.55 inches in
diameter. In the illustrated arrangement, two of these batteries 66
are located at one side of the circuit board 48 and the other two
batteries 66 are located on the opposite side of the circuit board
48. The batteries 66 may be positioned within holders 70, 72
constructed to receive two batteries per holder. The holders 70, 72
may include snap-type connectors 74 at their ends to snap
.[.connected.]. .Iadd.connect .Iaddend.two .[.complimentary.].
.Iadd.complementary .Iaddend.connectors 76 at the ends of insulated
conductors which are at their opposite ends connected to conductors
provided on the circuit board 48.
The off/on switch 52 is connected in series with the battery group
64 and the trigger switch 16. When off/on switch 52 is in its on
position, and the trigger switch 16 is depressed, the current from
the battery group 64 is provided to an integrated circuit NAT LM
3909, in the manner illustrated by FIG. 5. The integrated circuit
NAT LM 3909 charges a capacitor .[.60.]. .Iadd.78.Iaddend.. Upon
each discharge of capacitor 78, a voltage pulse is sent to a
resistor 80. Resistor 80 reduces the voltage and the reduced
voltage is received at the base 82 of a transistor 84. Each time
that a voltage pulse is received at the base 82 of transistor 84,
transistor 84 is turned on and delivers a current pulse to the
diode 30. As earlier stated, the diode 30 is on somewhere between
about 10% to about 20% of the time, and is off the remainder of the
time. The current pulses are delivered to the diode 30 at a
frequency of about 60-100 cycles per second. The frequency is
established by the value of the capacitor 78. It is important that
a capacitor value be chosen that will result in the appearance of a
continuous light from the LED 30, and not a flickering light.
Referring back to FIG. 1, the night vision telescope 12 has an
objective lens 86 at its forward end, a light intensifier 88
between its ends, and either .[.an.]. .Iadd.the above-mentioned
.Iaddend.eyepiece .[.90.]. .Iadd.18 .Iaddend.or a connection for a
camera (not shown), etc. at its rear end.
As is known per se, the objective lens 86 is chosen to have a high
light gathering power. An image of the scene in front of the
objective lens 86, on which the beam of invisible light from the
projector 10 has been projected, is formed on the front or image
input of an input fiberoptic plate portion of the light intensifier
88. The fiberoptic plate is comprised of a bundle of thin optic
fibers whose ends .[.from.]. .Iadd.form .Iaddend.the front and rear
bounding surfaces of the plate. Each of the optical fibers passes
one element of the image formed on the input surface to a
photocathode deposited on the rear surface of the fiberoptic plate.
The resulting .[.images.]. .Iadd.image .Iaddend.formed on the
photocathode is therefore a mosaic of such elements. Each of the
fibers is sufficiently small so as not to limit the spatial
resolution of the image intensifier.
The photocathode is a photosensitive surface that emits electrons
in a spatial pattern corresponding to the intensity of the optical
image formed upon it by objective lens .[.66.]. .Iadd.86.Iaddend..
A suitable photocathic material is provided by evaporating in
vacuum a combination of the alkali .Iadd.and arsenic family
.Iaddend.metals potassium, sodium, antimony and cesium and
depositing them on a suitable transparent substrate. This process
yields a photocathode with a sensitivity from the visible into the
near-infrared spectral regions.
The electrons emitted from the photocathode impinge on the input
surface of a microchannel plate which multiplies them by thousands
of times through the process of cascaded secondary emission. The
multichannel plate consists of microscopic hollow-glass electron
conducting channels fused into a disk-shaped array. The walls of
these channels are specially processed to produce secondary
electrons. Voltage is applied across the disk faces so that each
microscopic channel represents a separate, high gain electron
multiplier. The voltage is supplied by batteries housed within a
housing 92 shown mounted atop the image intensifier 88. When an
electron impinges upon the electron surface channel plate,
secondary electrons are generated. The secondary electrons are
accelerated through the channels by the applied voltage, colliding
with the channel surfaces to dislodge additional secondary
electrons, thereby producing electron multiplication. By varying
the voltage across the disk, the gain of the multiplier can be
controlled. These electrons, now increased in number and energy,
impinge on a phosphor screen deposited on the front surface of a
fiberoptic output plate. The phosphor is suitably a yellow-green
phosphor having a spectral emission centered about 550 nanometers.
As in the input fiberoptic plate, the output fiberoptic plate is
also comprised of a bundle of optical fibers which relays the image
to a back or output phase of the fiberoptic plate; however, the
bundle is constructed with a 180 degree twist in order to invert
the otherwise upside down image produced by the objective lens
86.
An image intensifier 88 of the type described is produced by the
Litton Electron Tube Division of Litton Systems, Inc., of Tempe,
Ariz., as Image Intensifier Tube Model L-4261. Other known types of
image intensifier tubes having .[.construction.].
.Iadd.constructions .Iaddend.different from what is described above
can be substituted for the one described and are available from a
number of commercial sources.
In the illustrated embodiment, the intensified image of the field
of view, formed at the output surface of the fiberoptic plate, is
projected by the eyepiece lens 18 to the eye of the viewer. In
another embodiment, a camera body can be connected to the rear of
the telescope 12, so that the image can be recorded on film.
A viewer using a night vision system of the type disclosed by the
aforementioned U.S. Pat. No. 4,417,814, would see a bright dot at
the center of a dim yellow-green image. In contrast, a viewer using
the night vision system of the present invention would see a bright
yellow-green image, with faces, writing, and other detail clear and
discernible.
It is to be understood that the embodiment shown by the drawing,
and described above in reference to the drawing, is the best mode
at this time, but yet is merely an example of the form that the
invention may take. The scope of protection is to be determined by
the following claims interpreted in accordance with the rules of
patent claim interpretation, including the doctrine of
equivalents.
* * * * *