WO1999042783A1

WO1999042783A1 - Laser diode assembly for use in a small arms transmitter

Info

Publication number: WO1999042783A1
Application number: PCT/US1999/001323
Authority: WO
Inventors: Deepak Varshnea; Christopher Paul Owan
Original assignee: Cubic Defense Systems, Inc.
Priority date: 1998-02-18
Filing date: 1999-01-22
Publication date: 1999-08-26
Also published as: ZA991149B; TW421707B; AU2652899A

Abstract

A laser diode assembly for use in a small arms laser transmitter (ASAT) which may be affixed to the stock of a rifle such as an M16 used by a soldier in training with a multiple integrated laser engagement system (MILES). The laser assembly may include a housing assembly having a forward end with a window through which the beam of the laser diode is emitted. A pair of optical wedges are positioned inside the housing assembly between the laser diode and the window. The optical wedges are supported for independent rotation about a common optical axis for steering the laser beam. An alignment head may be physically mated to the rearward end of the housing assembly for driving a pair of shafts to rotate the optical wedges in the alignment of the transmitter to boresight the ASAT so that a soldier can accurately hit a target once he or she has located the target in the conventional sights of the rifle. The laser diode assembly is made of high-temperature resistant materials and adhesives to minimize variations in focal length that would otherwise result in undesirable laser beam dispersion.

Description

-1-

LASER DIODE ASSEMBLY FOR USE IN A SMALL ARMS TRANSMITTER

TECHNICAL FIELD

The present invention relates to military training equipment, and more particularly, to an improved laser diode assembly used in a laser transmitter mounted on a rifle for use by a soldier in war games.

BACKGROUND ART

For many years the armed services of the United States have trained soldiers with a multiple integrated laser engagement system (MILES). One aspect of MILES involves a small arms laser transmitter (SAT) being affixed to the stock of a rifle such as an Ml 6. Each soldier is fitted with detectors on his helmet and on a body harness adapted to detect a laser "bullet" hit. The soldier pulls the trigger of his or her rifle to fire a blank to simulate the firing of an actual round and an audio sensor triggers the transmitter.

When fitting the SAT to the rifle barrel, it is necessary to align the transmitter so that a soldier can accurately hit a target once he or she has it located in the conventional rifle sights. In the past, the SAT was bolted to the rifle stock and the mechanical or so-called "iron" sights of the weapon were adjusted to align with the laser beam. The disadvantage of this approach is that the mechanical weapon sights must be readjusted in order to use the rifle with live rounds. To overcome this disadvantage, later SATs incorporate mechanical linkages for changing the orientation of the laser.

Aligning the SAT is generally performed using a fixture. The prior art small arms alignment fixture (SAAF) used by the U. S . Army for alignment of the conventional MILES

SAT consists of a complex array of one hundred forty-four detectors which are used in conjunction with thirty-five printed circuit boards to determine where the laser hits with respect to a target reticle. The difficulty in using the prior art SAAF is that the soldier aims his or her weapon at the array which is twenty-five meters away without the use of a stable platform. In many cases, the soldier fires his or her weapon in a manner which results in the aim point not being at the desired location. The fact that the array is located twenty-five -2-

meters away from the soldier also introduces visibility limitations due to snow, fog, wind and poor lighting conditions at sunrise or dusk.

Furthermore, the prior art SAAFs calculate the number of error "clicks" in both azimuth and elevation. The number of clicks is then displayed on the prior art SAAF using four sets of electro-mechanical display indicators. A soldier must turn his conventional

SAT's adjustors the corresponding number of clicks in the correct direction. He or she must then aim and fire the weapon again and make additional corresponding adjustments. This iterative process continues until the soldier obtains a zero indication on the prior art SAAF. This is a very time consuming and tedious process due to normal aiming errors incurred each time the soldier has to reacquire the target reticle. It is not uncommon for a soldier to take fifteen minutes to align his or her weapon to the best of his or her ability and still not have it accurately aligned.

Not only is the alignment process utilizing the prior art SAAF time consuming, it also expensive because a large amount of blank ammunition must be used. The laser of a conventional SAT will not fire without a blank cartridge being ignited or by using a special dry fire trigger cable. The prior art SAAF does not support optical sights, different small arms weapon types, nor night vision devices. Nor does the prior art SAAF accurately verify the laser beam energy and encoding of a received laser beam.

In response, SATs which eliminate the need to utilize a large target array were developed. The transmitters are adjustable for more rapid and accurate alignment and the output. The transmitters feature adjustable powers and coding to enable the man-worn portion of a MILES system to discriminate between kills made by different small arms and different players. Known SATs use a laser diode to generate the laser beam used to sight the small arms rifle. However, current SATs may be limited in the range in which they are effective. This limitation arises due to physical changes experienced by the SAT when subjected to internal and ambient temperature changes which commonly occur in the field where the weapon is being used. For example, multiple detonations of a blank cartridge may cause the rifle barrel and the SAT attached thereto to become heated, or the weapon may be used in sub-zero temperatures where the ambient temperature adversely affects the SAT. This type of heating or cooling may cause the laser diode of the SAT to decrease in effectiveness, resulting in a reduced intensity laser beam. When this occurs, shots which should result in kills may not be detected and logged as kills.

Accordingly, it would be desirable to provide a laser diode assembly for use in an advanced small arms transmitter which would allow the SAT to be functional over a wide range of temperatures. Such a laser diode assembly would also preferably decrease the dispersion of the laser beam emanating from the SAT. In addition, the laser diode assembly would have a modular construction, thereby minimizing manufacturing overhead and allowing for increased serviceability in the field.

DISCLOSURE OF INVENTION Accordingly, it is the primary obj ect of the present invention to provide an improved laser diode assembly for use in an advanced small arms laser transmitter (ASAT) employed in a multiple integrated laser engagement system.

The present invention provides a laser diode assembly which has an increased effective range when the assembly is subjected to temperature variation. That is, the laser diode assembly, when used integral to a SAT, increases the effective "hit" range of the SAT over that currently found in prior art SATs. The assembly includes a modular construction that reduces the cost of manufacturing while increasing control over manufacturing tolerances. The laser diode assembly comprises a generally cylindrical support body having a hollow interior and a laser diode tube coupled to a first end of the support body in an alignment so that a laser beam emitted by a laser diode mounted in the laser diode tube will travel through the hollow interior of the support body. The laser diode assembly further comprises an optical wedge assembly coupled to a second end of the support body in an alignment so that the laser beam emitted by the laser diode will travel through the optical wedge assembly and can be steered (aimed) by the optical wedge assembly.

BRIEF DESCRIPTION OF DRAWING

The objects, advantages and features of this invention will be more readily appreciated from the following detailed description, when read in conjunction with the accompanying drawing, in which: -4-

FIG. 1 is a perspective view illustrating a soldier aiming his or her rifle in a prior art automatic player identification small arms laser alignment system using one embodiment of an ASAT constructed in accordance with the present invention;

FIG. 2 is an enlarged exploded isometric view of a preferred embodiment of our advanced small arms transmitter (ASAT), illustrating one embodiment of our laser diode assembly, which is mounted on the rifle illustrated in FIG. 1 ;

FIG. 3 is a diagrammatic vertical sectional view of a part of the laser diode assembly of FIG. 2 illustrating further details of its construction;

FIG. 4 is a diagrammatic side elevation view of the laser diode assembly of FIG. 3 illustrating an ideal dispersion angle of zero of the laser beam generated by the assembly;

FIG. 5 is a diagrammatic side elevation view of the laser diode assembly of FIG. 3 illustrating an actual two-dimensional dispersion angle α of the laser beam generated by the assembly;

FIG. 6 is an exploded perspective of an alternate embodiment of an ASAT embodying the present invention;

FIG. 7 is an enlarged isometric view of a mounting strap of the ASAT of FIG. 6; and

FIG. 8 is an enlarged front-elevation view of the mounting strap of FIG. 7 illustrating the position of a rifle barrel in phantom lines that is clamped between the mounting strap and the housing base of the ASAT.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIG. 2, the preferred embodiment of our invention is illustrated in the form of an advanced laser small arms transmitter (ASAT) 200 which may be bolted to the barrel 44 (FIG. 1) of a small arms weapon 14 such as an Ml 6 rifle for use by a soldier in war games. The ASAT 200 is designed to be automatically adjusted by an alignment system 10 (FIG. 1). The alignment system 10 is described in detail in U.S. Patent No. 5,410,815 mentioned above. While the ASAT 200 is illustrated in FIG. 1, its construction is not part of the prior art. The alignment system 10 includes a rectangular hollow transit case 16 which is horizontally oriented when in use. A lockable hinged end cover 18 of the case 16 may be swung upwardly to reveal a control unit 20 mounted to the inside thereof. A soldier 21 aims the rifle 14 inside the case 16. The soldier 21 wears a helmet 21a and a harness 21 b -5-

equipped with laser detectors which detect laser "bullet" hits in subsequent war games. The control unit 20 includes a box-like housing having an LCD display 24. The housing 22 may include a keypad in the form of a membrane switch panel.

A retractable sliding rack 40 (FIG. 1 ) may be extended horizontally from the rear end of a base unit 42 mounted to the bottom wall of the case 16. The barrel 44 of the rifle 14 is firmly supported on the apex of a rigid triangular weapon rest 46 whose base is securely mounted via bolts to an intermediate portion of the base unit 42. A magazine 47 of the rifle 14 is mounted in a holder 48 on the rack 40. The holder 48 has knobs 50 and 52 for manually adjusting the azimuth and elevation, respectively, of the barrel 44 of the rifle 14. After mounting the rifle 14 on the weapon rest 46 and holder 48, the soldier 21 aims at an image of a target reticle projected in the line of sight of the weapon.

A box-shaped optics unit 56 (FIG. 1) is rigidly mounted on the forward portion of the base unit 42. The optics unit 56 includes a convex lens and a beam splitter. The beam splitter is transparent to the laser beam from the ASAT 200 but reflective to visible light. The target reticle is mounted inside the optics unit 56 below the axis of the laser beam. The beam splitter is positioned forward of the lens 58 and is angled to project the image of the target reticle through the lens 58 at infinity. A position sensor detector in the optics unit 56 receives the laser beam and generates an error signal representative of a displacement between a received location of the laser beam and the image of the target reticle. The ASAT 200 is then mechanically adjusted by an alignment head 15 until its laser beam strikes the center of the detector.

The initial set-up of the alignment system 10 of FIG. 1 involves three simple steps which include installation of a battery into the control unit housing 22, activating the control unit 20, and selecting the weapon type to be aligned. The display 24 gives appropriate text messages and directions to the operator as to how to proceed to the next step. Once the alignment system 10 is ready for alignment the soldier 21 follows the directions on the display 24 to align his or her weapon. In the event any problems are encountered by the alignment system 10 during the alignment process such as low power, incorrect laser coding or triggering problems, the system will inform the soldier that the weapon's ASAT 200 is defective and needs to be replaced. The optics unit 56 (FIG. 1) is the assembly which projects the illuminated target reticle to the soldier 21 during boresighting and senses the location of the laser beam of the ASAT 200 with respect to the reticle. The illuminated reticle assists the soldier 21 in boresighting during reduced lighting conditions such as dusk or dawn. Referring to FIG. 2, the ASAT 200 is an electro-mechanical device that, in conjunction with an alignment head 15 shown in FIG. 1, automatically aims or adjusts the laser beam emitted thereby as directed by the control unit 20. The ASAT 200 may include an inductive coil (not illustrated) which is used to trigger the laser diode in the ASAT 200 and, if requested via control unit 20, utilizes a testing player identification (PID). The ASAT 200 may also have a detector which monitors its fire LED (not shown) to determine its operational status. Two miniature reduction geared motors and associated offset gear trains (not illustrated) within the alignment head 15 are used to rotate a pair of shafts (not illustrated) coupled to the ends of a pair of drive shafts 218 and 220 inside the ASAT 200. The motors of the alignment head 15 are driven and controlled by the control unit 20 during the boresighting process while the optics unit 56 senses the laser beam emitted by the ASAT

200 and provides real time feedback to the control unit 20.

The ASAT 200 illustrated in FIG. 2 includes a modular housing assembly having a base 202 and a removable top cover 204. The base 202 and top cover 204 are preferably made of stainless steel which is heat treated. A laser diode assembly generally designated 300 is mounted within the housing assembly base 202 and top cover 204. The laser diode assembly 300 is energized by a power circuit on a controller board 206 that is also mounted within the housing assembly. The power circuit is actuated to energize the laser diode assembly 300 by an inductive switch (not illustrated) mounted to the inside of the base 202 of the modular housing assembly. The inductive switch may be actuated by energization of an induction coil (not illustrated).

The forward end of the removable top cover 204 is formed with a pair of round apertures or holes 208 and 210. An audio and/or optical sensor (not illustrated) for detecting the firing of a blank cartridge is located behind the hole 210 and connected to the controller board 206. A transparent window 212 is fitted into a retainer ring 214 that is mounted in the hole 210. The window 212 allows an optical and an audio signal to be received by the sensors, but protects the ASAT 200 from infiltration by foreign objects. -7-

Another transparent window 222 permits passage of the laser beam from the laser diode assembly 300. The window 222 is fitted into a retainer ring 216 that is mounted in the other hole 208. Lenses in the form of optical wedges 224 and 226 with angled opposing faces are supported behind the window 222 for independent rotation via the drive shafts 218 and 220, respectively.

The optical wedges 224 and 226 (FIG. 2) are surrounded by, and supported within, rings 228 and 230, respectively. The rings 228 and 230 include partially toothed outer perimeters which may be engaged by pinon gears 218a and 220a to independently rotate the optical wedges 224 and 226 when the drive shafts 218 and 220 are turned. The drive shafts 218 and 220 are journaled in bearing holes 219 and 221 which extend through a tubular or cylindrical support body 236 having a relatively large, longitudinally extending hollow bore. The rear ends of the drive shafts 218 and 220 extend through the housing assembly 202 and may be sealed by O-rings (not illustrated). The drive shaft ends are protected by a rigid flange 244 (partially shown) that may extend perpendicularly from the removable cover 204 or from the housing assembly 202. When the alignment head 15 (FIG. 1) is coupled to the housing assembly of the ASAT 200, the non-slip couplings on the shafts (not shown) of the alignment head 15 connect with the ends of the shafts 218 and 220 to provide driving connections to the alignment head motors.

A planar, vertically extending mounting base 234 (FIG. 2) is coupled to the support body 236 and is used to removably couple the laser diode assembly 300 to the base 202 of the modular housing assembly. A cylindrical laser diode tube 242 is connected, via a coupling sleeve 238 to the rear end of the support body 236. A lens 240 is supported inside the coupling sleeve 238. A high-temperature resistant epoxy or other suitable adhesive (not illustrated) is used to connect the laser diode tube 242, lens 240, coupling sleeve 238 and support body 236. The use of this special adhesive precludes thermally-induced offsets which would otherwise be experienced by the laser diode tube 242 with respect to its longitudinal optical axis. The lens 240 may be laser welded to the laser diode tube 242 instead of using adhesive to couple these two parts.

In the preferred embodiment, the laser diode tube 242 emits laser light having a wavelength of between approximately twelve and one-half and forty microns. The term

"tube" as used in reference to the laser diode tube 242 includes any housing or other support structure, cylindrical or otherwise shaped, that serves as a convenient device for mounting and carrying a laser diode.

The optical wedge assembly is coupled to the forward end of the cylindrical support body 236 (FIG. 2). As mentioned above, the optical wedge 224 is coupled to the ring 228 and the optical wedge 226 is coupled to the ring 230. A circular retainer 252 cooperates with an end plate 232 having a control hole or aperture to rotatably and securely hold the optical wedges 224 and 226 within the body 236.

As illustrated in FIG. 2, the retainer 252 is washer shaped and has an elevated boss 252a extending from one side in the direction of the end plate 232. The side of the retainer 252 which faces opposite the end plate 232 engages the face of optical sleeve 238 when the laser diode assembly 300 is assembled. Likewise, the end plate 232 contacts a raised boss 230a of ring 230. The opposite face of the ring 230 contacts a raised boss 228a of the ring 228 positioned immediately opposite.

During assembly of the laser diode assembly 300 (FIG. 2), the drive shafts 218 and 220 are placed through the holes 219 and 221 and in a position to engage the pinon gears 218a and 220a with the spur gear or toothed portions of the rings 228 and 230. The optical wedges 224 and 226 are also coupled to the rings 228 and 230 using the same type of high-temperature resistant epoxy or adhesive. Likewise, the retainer 252 and the end plate 232 may be coupled to the optical sleeve 238 and the support body 236, respectively, using the same high-temperature resistant adhesive. The optical wedges 224 and 226 can be independently rotated about a longitudinal axis of the laser diode assembly 300 that is substantially coincident with the laser beam for steering (aiming) the same.

One suitable high-temperature resistant adhesive is a cure epoxy such as that manufactured and sold under the trademark Epotk 353 ND. This epoxy is cured at high temperatures to achieve a Tg which is at least approximately ten to fifteen percent higher than the maximum expected operating temperature for the ASAT 200. Preferably, the epoxy is stabilized using a ceramic or glass powder. Another suitable epoxy is Epon 828 with Nerasmid 140 hardener in proportions that produce a mix whose Tg is much higher than the temperature experienced by the diode assembly 300 during normal usage of the ASAT 200. An appropriate fixture (not illustrated) is used to hold the laser diode assembly 300 together while the epoxy cures. -9-

It is important that the materials for the laser diode tube 242, lens 240, coupling sleeve 238 and support body 236 also be made of high-temperature resistant materials having a Tg which is at least approximately ten to fifteen percent higher than the maximum expected operating temperature for the ASAT 200. The same is true of the rings 228 and 230, the retainer 252 and the optical wedges 224 and 226. By way of example the lens 240 is made of C0550 material from Corning Glass and the optical wedges may be made of SF 12 material from Geltek, Inc. The other components of the laser diode assembly 300 may be made of commercially available KOVAR (Trademark) material.

The construction of the ASAT 200 using a modular design allows the laser beam dispersion problems of the prior art to be overcome. Further, by using a non-ultra violetly cured high temperature epoxy to construct the modular assembly, gains can be achieved in reducing the cost of manufacturing.

The ASAT 200 shown in FIG. 2 has mounting straps 246 and 248 which are coupled to one side of the base 202 of the housing assembly at one end using four pins. Three of these pins 250a, 250b and 250c are visible in FIG. 2. The pins extend through aligned holes formed in downwardly extending parallel flanges on the base 202. The attachment strap 246 may be pivotably coupled to the base 202 of the housing assembly using pin 250a. A second pin 250b is coupled to the base 202 of the housing assembly and positioned opposite from the first pin 250a. The strap 246 is additionally shaped to allow it to be removably attached to the base 202 of the housing assembly when engaged with the second pin 250b. Similarly, the strap 248 may be coupled to alternate locations on the base 202 of the housing assembly using the two remaining pins. When used separately or in unison, the straps 246 and 248 may be positioned around the barrel 44 of the rifle 14 (illustrated in FIG. 1) and removably coupled with pins 250a, 250b, 250c etc. in order to secure the ASAT 200 to the barrel. This type of attachment mechanism allows for easy removal of the ASAT 200 from the barrel 44 of a rifle 14 when desired.

FIG. 3 is a vertical sectional view of the laser diode assembly 300 shown in FIG. 2. Surrounding portions of the ASAT 200 are illustrated in phantom lines. The mounting base 234 extends from the body 236 and allows the laser diode assembly 300 to be mounted in the base 202 of the housing assembly. The laser diode tube 242 has a common longitudinal optical axis 241 which is shared with the optical wedges 224 and 226 (FIG. 2). A solid state -10-

laser diode shown diagrammatically at 242a (FIGS.4 and 5) is mounted at a fixed central location within the rear end of the laser diode tube 242. The laser diode 242a may be supported inside a metal can that is affixed to the base of the tube 242 with the same type of high temperature resistant epoxy identified herein. Alternatively, the can containing the laser diode 242a may be laser welded to the tube 242. The end plate 232 (FIG. 3) caps the cylindrical support body 236 at its forward end and the laser diode tube 242 caps the support body 236 at its rearward end. For clarity purposes, the drive shafts 218 and 220 and the pinion gears 218a and 220a engaged on the spur gears integral to the sleeves 228 and 230 are shown in part. The removable cover 204 is shown in phantom lines in FIG. 3 as is a portion of the base 202 of the housing assembly. As best seen in FIG. 3, the laser diode tube 242 has a long cylindrical outer housing which is substantially contained within the cylindrical support body 236.

Referring to FIG. 4, the laser diode assembly 300 emits a laser beam 402 when energized. Ideally, the laser beam 402 does not substantially disperse, i.e., it does not lose intensity at increasing distances from the laser diode 242a due to beam spreading. In other words, the distance τ - representing a distance from the edge of the laser beam to the beam's centerline - remains substantially constant. This dispersion characteristic is related to the focal length/ of the lenses used in the laser diode assembly 300, a relationship well known to those skilled in the art and further discussed below. A focal length / is illustrated in FIGS. 4 and 5, where the number immediately preceding or succeeding /indicates a multiple of/ A focal length equals the distance from the laser diode 242a to the lens assembly of the laser diode assembly 300 as shown in FIG. 2. In other words, if the distance from the laser diode 242a to the lens assembly is increased, the distance from the lens assembly to the point marked/in FIG. 5 also increases. In FIG. 4, the laser beam 402 has a dispersion angle of zero (i.e., it does not disperse) and the laser beam relative to the optical axis 241 is substantially constant over a given distance. For boresighting purposes, the laser beam 402 remains aligned with a centerline (CL) 404 of the barrel 406 of the rifle 14.

FIG. 5 illustrates beam dispersion in the preferred embodiment of the present invention. The ASAT 200 is shown mounted on a barrel 406 having a boresight 404. The laser beam 402 suffers a loss of intensity because τ increases as a function of the distance -11-

from the lens at which the laser beam intensity is measured. Accordingly, to control beam dispersion, the focal length in the preferred embodiment is set between 6.24 millimeters and eighteen millimeters. The dispersion angle α may vary depending upon whether an increase or decrease in temperature is adversely affecting the laser diode assembly 300. For example, as multiple blank cartridges are fired and the rifle 14 is repeatedly sighted using the ASAT

200, resulting in multiple enerizations of the laser diode 242a, the barrel 44 might expand. This expansion is caused by the heating of the barrel 406 due to the firings as well as the heating of the ASAT 200, resulting in the expansion of the materials used to construct both the rifle 14 and the ASAT 200. If the support body 236 and other components of the laser diode assembly 300 expand due to heating, the focal distance between the laser diode 242a and the lens assembly proportionately increases. This proportional increase may also increase the dispersion angle α and may result in a decreased intensity in the laser beam 402. Also, the increase in the dispersion angle α also results in the distance τ - the distance from the optical centerline to the laser beam at a given distance - to increase greatly, thereby enlarging the laser beam pattern. The result is that the laser beam 402 loses intensity and may not activate MILES indicators worn by a soldier engaged in a staged conflict. At closer ranges, the dispersion of the laser beam can result in a hit being incorrectly recorded. For example, a "laser" hit might result although a live cartridge fired through the barrel of the rifle 14 would not have resulted in a hit. In other words, the laser beam 402 is no longer aligned with the boresight 404 of the rifle 14.

The difficulties described with respect to the reduced intensity of the laser beam 402 when used in a laser engagement system are overcome by the present invention. The modular construction of the laser diode assembly 300 used in the ASAT 200 as described above allows the physical tolerances of the laser diode assembly 300 to be maintained during temperature variations below the maximum expected operating temperature of the ASAT 200. It is possible to align the mechanical axis to the optical axis with tolerances better than one mrad. This may be accomplished by selecting a lens/number of approximately three and a laser diode 242a whose near field effective waist diameter is relatively constant over the fabrication tolerances. -12-

Further, the tubular overlapping, staged construction of the laser diode assembly 300 overcomes limitations of the prior art with respect to laser beam dispersion and loss of intensity. The modular design of the present invention, the utilization of a high-temperature resistant adhesive in manufacturing as described above, and the utilization of special high- temperature resistant materials reduces the dispersion of the laser beam.

FIG. 6 illustrates an alternate embodiment 500 of the ASAT that is similar to the

ASAT 200 of FIG. 2 as indicated by the parts denoted with similar reference numerals. A deformable gasket 502 which may be made of a suitable elastometic material provides a watertight seal between the base 202' and the cover 204 of the housing assembly of the ASAT 500. A single generally L-shaped mounting clamp or strap 504 is connected with a pin (not illustrated) to trunnions (not illustrated) one side of the base 202'. The mounting strap 504 is also connected to a mounting block portion 202'a of the base 202' via bolt assemblies 506 and 508. As seen in FIGS. 7 and 8, one end 504a of the mounting strap 504 is formed with vertical bores 504b and 504c for receiving therethrough the bolt assemblies 506 and 508, respectively. The other end 504d of the mounting strap 504 is formed with a horizontal bore 504e for receiving a mounting pin (not illustrated). The central region of the mounting strap 504 is formed with bosses 504f upon which the barrel 44 of the rifle 14 rests. The barrel 44 is squeezed between the strap 504 and the underside of the base 202'.

The mounting strap 504 is preferably machined from stainless steel and heat treated. The strap 504, base 202' and cover 204 must be made of materials that provide adequate strength while minimizing induced stress warpage.

While we have described two different embodiments of an ASAT utilizing our laser diode assembly it should be apparent to those skilled in the art that our invention may be further modified in both arrangement and detail. Therefore, the protection afforded our invention should only be limited in accordance with the scope of the following claims.

What is claimed is:

Claims

-13-CLALMS

1. A laser diode assembly for a small arms transmitter, comprising: a generally cylindrical support body having a hollow interior; a laser diode tube; means for coupling the laser diode tube to a first end of the support body in an alignment so that a laser beam emitted by a laser diode mounted within the laser diode tube will travel through the hollow interior of the support body; an optical wedge assembly for steering the laser beam; and means for coupling the optical wedge assembly to a second end of the support body in an alignment so that the laser beam emitted by the laser diode will travel through the optical wedge assembly for steering thereby.

2. The laser diode assembly of Claim 1 wherein the first coupling means is made of a high-temperature resistant material that minimizes changes in a focal distance between the laser diode and the optical wedge assembly.

3. The laser diode assembly of Claim 1 wherein the second coupling means is made of a high-temperature resistant material that minimizes changes in a focal distance between the laser diode and the optical wedge assembly.

4. The laser diode assembly of Claims 2 or 3 wherein the first coupling means and the second coupling means further include a first quantity and a second quantity, respectively, of a high- temperature resistant adhesive that minimizes changes in a focal distance between the laser diode and the optical wedge assembly.

5. The laser diode assembly of Claim 2 wherein the high-temperature resistant material has a Tg which is at least approximately ten to fifteen percent higher than a maximum expected operating temperature. -14-

6. The laser diode assembly of Claim 3 wherein the high-temperature resistant material has a Tg which is at least approximately ten to fifteen percent higher than a maximum expected operating temperature.

7. The laser diode assembly of Claim 4 wherein the high-temperature resistant adhesive has a Tg that is at least approximately ten to fifteen percent higher than a maximum expected operating temperature.

8. The laser diode assembly of Claim 1 wherein the first coupling means further includes a coupling sleeve.

9. The laser diode assembly of Claim 1 wherein the second coupling means further includes a circular retainer.

10. The laser diode assembly of Claim 1 wherein the optical wedge assembly includes a pair of optical wedges, each wedge being mounted in a surrounding ring for independent rotation about a longitudinal axis substantially coincident with the laser beam for steering the beam.

11. A small arms transmitter, comprising: a housing assembly having a hollow interior and a forward end with at least one aperture formed therein; means for removably mounting the housing assembly on a rifle; and a laser diode assembly mounted within the housing including a laser diode tube, an optical wedge assembly, and means for coupling the laser diode tube and optical wedge assembly together within the housing in an alignment for steering a laser beam emitted by a laser diode mounted within the laser diode tube through the aperture, the coupling means being made from a material selected to minimize changes in a focal distance between the laser diode and the optical wedge assembly otherwise due to changes in an operating temperature of the laser diode assembly. -15-

12. The small arms transmitter according to Claim 11 wherein the coupling means includes a cylindrical support body having a hollow bore and made of a high- temperature resistant material, a first quantity of a high-temperature resistant adhesive connecting the laser diode tube to a rear end of the cylindrical support body and a second quantity of the high-temperature adhesive connecting the optical wedge assembly to a forward end of the cylindrical support body.

13. The small arms transmitter according to Claim 12 wherein the high- temperature resistant material and adhesive each has a Tg which is at least approximately ten to fifteen percent higher than a maximum expected operating temperature.

14. The small arms transmitter according to Claim 12 wherein the coupling means further includes a coupling sleeve connected between the laser diode tube and the rear end of the cylindrical support body.

15. The small arms transmitter according to Claim 12 wherein the coupling means further includes a circular retainer between optical wedge assembly and the forward end of the cylindrical support body.

16. The small arms transmitter according to Claim 12 wherein the optical wedge assembly includes a pair of optical wedges, each wedge being mounted in a surrounding ring for independent rotation about a longitudinal axis substantially coincident with the laser beam for steering the beam.

17. The small arms transmitter according to Claim 16 wherein the cylindrical support body has a pair of bearing holes formed therein which extend in a longitudinal direction for each receiving a corresponding drive shaft for independently rotating the rings that surround the optical wedges.

18. The small arms transmitter according to Claim 11 and further comprising a controller board mounted within the housing. -16-

19. The small arms transmitter according to Claim 11 wherein the removable mounting means includes a plurality of straps held via pins that extend through aligned holes in flanges that extend downwardly from a base of the housing.

20. A laser diode assembly for a small arms transmitter, comprising: a generally cylindrical support body having a hollow interior and made of a high- temperature resistant material; a generally cylindrical laser diode tube; means for coupling the laser diode tube to a first end of the cylindrical support body in an alignment so that a laser beam emitted by a laser diode mounted within the laser diode tube will travel through the hollow interior of the support body, the first coupling means including a coupling sleeve made of the high-temperature resistant material and a first quantity of a high-temperature resistant adhesive; optical wedge assembly means for steering the laser beam emitted by the laser diode, including a pair of optical wedges mounted in corresponding rings for independent rotation about a longitudinal axis substantially coincident with the laser beam; and means for coupling the optical wedge assembly to a second end of the cylindrical support body in an alignment so that the laser beam emitted by the laser diode will travel through the optical wedge assembly so that the optical wedge assembly can steer the laser beam through independent rotation of the rings, including a retainer made of the high- temperature resistant material and a second quantity of the high-temperature resistant adhesive, the high-temperature resistant material and the high-temperature resistant adhesive each having a Tg that is at least approximately ten to fifteen percent higher than a maximum expected operating temperature in order to minimize changes in a focal distance between the laser diode and the optical wedge assembly.