WO1999024755A1

WO1999024755A1 - Self-contained laser illuminator module

Info

Publication number: WO1999024755A1
Application number: PCT/US1998/001662
Authority: WO
Inventors: John D. German; Eric J. Cramer; Michael D. Tocci; Brian K. Spielbusch; Steven J. Saggese
Original assignee: Science & Engineering Associates, Inc.
Priority date: 1997-11-10
Filing date: 1998-01-29
Publication date: 1999-05-20
Also published as: AU7464798A

Abstract

A self-contained laser illuminator module (10) for primary use in a laser security device which is adapted to produce an optimally effective and eye-safe laser beam for use as a laser visual countermeasure. The laser illuminator module (10) includes control electronics (41) having a high-power laser (38) adapted to generate a preselected wavelength and intensity, a fiber optic means (31) in optical communication with the control electronics (41), and a means for mounting (21) to a security device having a collimating lens (22). The present invention generates a laser beam to illuminate or create temporary visual impairment of a potential adversary which results in hesitation, delay, distraction, surrender or retreat.

Description

SELF-CONTAINED LASER ILLUMINATOR MODULE

This invention is a continuation-in-part of U.S. Patent Application Serial No.

08/518,230, filed August 23, 1995 entitled "Eye Safe Laser Security Device" which is

hereby incorporated by reference. Portions of this invention were also developed

with United States Government support under Contract No. F19628-96-C-0085

awarded by the United States Air Force. The Government has certain rights to this

invention.

Field of the Invention

This invention relates to non-lethal, non-eye damaging laser security devices, such

as those described in the above-referenced patent application, and the use of such

devices as non-damaging weapons and security systems to provide warning and/or

visual impairment through illumination by bright, visible laser beams. Specifically,

such devices require laser light at predetermined wavelengths, beam diameters,

intensities, and intensity distributions within the beam and to create temporary visual

impairment (by glare and/or flashblinding) to cause hesitation, delay, distraction, and

reductions in combat and functional effectiveness when used against humans in

military, law enforcement, corrections (prisons) and security applications. To

maximize the effectiveness of laser security devices while minimizing the risk of eye

injury, the laser beam produced by these devices must be optimized through creative optical, electrical, and mechanical design. Furthermore, it important to

make portable versions of laser security devices smaller and lighter so that the users

are not hampered in their ability to carry and apply them.

Background of the Invention

In the present domestic and world political climate, U.S. military forces are faced

with a growing number of situations in which less-than-lethal response options are

essential. Recent examples include Somalia, Cuban refugee camps and Haiti, as

well as riots in Los Angeles. In these types of situations, where military, political and

humanitarian objectives preclude the use of lethal force except when personnel are

in immediate danger, the individual soldier must have less-than-lethal options

available to him or her to warn, deter, delay, or incapacitate a wide range of

adversaries.

Low-energy lasers can be effective, non-lethal weapons for a variety of military

missions as well as civilian law enforcement applications. Through the effect of

illumination, glare, flashblinding and psychological impact, lasers can create

hesitation, delay, distraction, temporary visual impairment, and reductions in combat

and functional effectiveness when used against local inhabitants trying to steal

supplies, intruders, military and paramilitary forces, terrorists, snipers, criminals and

other adversaries. Furthermore, if continuous-wave or repetitively pulsed lasers having the required intensity are used, these effects can be created at eye-safe

exposure levels below the maximum allowed by international safety standards. The

low-energy laser systems used to produce these effects are called laser visual

countermeasure devices.

As disclosed in the present invention, additional specific applications for which such

lasers would enhance effectiveness include security for military and industrial

facilities, apprehension of unarmed but violent subjects, protection from suspected

snipers, protection from assailants and crowd/mob control. Another important class

of applications are those which limit the use of potentially lethal weapons because

innocent people are present. These include hostage situations, protection of

political figures in crowds, airport security, and prison situations where guards are

present. A similar situation occurs when use of firearms or explosives in the

battlefield may cause unacceptable collateral damage to friendly personnel,

equipment or facilities (including aircraft or electronic equipment). Finally, there are

portable applications, such as raids on hostile facilities and hostage rescues, where

even a few seconds of distraction and visual impairment can be vital to the success

of the mission.

Until recently, the relatively large size of laser-producing components have

prevented the use of laser technology in personal protection or security applications. In recent years, however, compact laser-producing components have made the

benefits of laser technology available to numerous applications, such as compact

disc players, medical tools and welding appliances.

Lasers are capable of a wide range of effects on human vision which depend

primarily on the laser wavelength (measured in nanometers), beam intensity at the

eye (measured in watts/square centimeter), and whether the laser is pulsed or

continuous-wave. These effects can be divided into three categories: (1) glare; (2)

flashblinding; and (3) retinal lesion.

The glare effect is a reduced visibility condition due to a bright source of light in a

person's field of view. It is a temporary effect that disappears as soon as the light

source is extinguished, turned off or directed away from the subject. If the light

source is a laser, it must emit laser light in the visible portion of the wavelength

spectrum and must be continuous or rapidly pulsed to maintain the reduced visibility

glare effect. The degree of visual impairment due to glare depends on the ambient

lighting conditions and the location of the light source relative to where the person is

looking. In bright ambient lighting, the eye pupil is constricted, allowing less laser

light into the eye to impair vision. Also, if the laser is not near the center of the

visual field, it does not interfere as much with an individual's vision. In contrast, the flashblind effect is a temporary reduction in visual performance

resulting from exposure to any intense light, such as those emitting from a

photographic flashbulb or a laser. The nature of this impairment makes it difficult for

a person to discern objects, especially small, low-contrast objects or objects at a

distance. The duration of the visual impairment can range from a few seconds to

several minutes, and depends upon the amount of light intensity employed, the

ambient lighting conditions and the person's visual objectives. The major difference

between the flashblind effect and the glare effect is that visual impairment caused by

flashblind remains for a short time after the light source is extinguished, whereas

visual impairment due to the glare effect does not.

The effectiveness of a given laser as a security device is directly related to how

bright the laser appears to the eye. The apparent brightness of a laser is a function

of the laser intensity at the eye and the laser wavelength. The intensity at the eye,

measured in watts per square centimeter, can be increased by control of the laser

output power level and laser beam size. The wavelength, however, is a function of

the type of laser employed and is therefore more severely constrained by the limited

laser options available which are suitable for the security device applications of the

present invention.

If the intensity of a laser beam at the eye exceeds a certain level, injury to the retina may occur in the form of lesions (i.e., small burns at the focal spot of the laser

beam). To ensure that laser security devices are non-damaging to the human eye,

the intensity present at the subject's eye must be below the threshold for permanent

damage. The definitive laser safety parameter as defined by the American National

Standards Institute in ANSI Z136.1-1993 is the Maximum Permissible Exposure

(MPE) which is measured in watts per square centimeter for continuous (non-

pulsed) laser beams. If the laser intensity anywhere within the beam diameter

exceeds the MPE, the possibility of retinal injury exists. The value of the MPE for

short (e.g., quarter second) exposures to visible laser light is 2.55 milliwatts per

square centimeter.

Prior art in the area of self-contained laser devices focus on low-power lasers (i.e.,

output laser power of less than 5 milliwatts) such as those used in laser pointers

(e.g., Edmund Scientific Stock Number P38.914), surveying equipment, alignment

lasers, and laser gun sights. For these devices, the issues that are important for

eye-safe laser security devices (i.e., maximum beam intensity, beam intensity

profile, and beam uniformity) do not play a significant role in design. Furthermore,

with these very low-power lasers, diode cooling and thermal management are not

important issues. As such, the present invention resolves six key problems which

must be considered in the design of laser illuminator subsystems for eye-safe laser

security devices: (1) distribution of laser power within the beam diameter, (2) control of the laser power output, (3) size, (4) mechanical stability, (5) thermal management,

and (6) impact of the laser on the adversary.

The first problem examines the laser power. The laser power within a typical laser

beam is not evenly distributed throughout the diameter of the beam. This means

that the laser power usually concentrates in one or more intensity peaks within the

beam. The output beam from a semiconductor laser diode (i.e., laser) is particularly

poor in this respect, having a sharply peaked intensity distribution. Laser diode

beams also provide design difficulties because they are highly elliptical and exhibit

sufficient astigmatism to redistribute the beam intensity as the distance from the

laser increases. Figure 1 shows the intensity profile of such a beam. For eye safety

purposes, it is desirable to minimize the number and magnitude of these "hot spots."

Also, because the eye perceives apparent brightness based on the average intensity

within the beam rather than the peak intensity, the effectiveness of a laser security

device is enhanced if the power is distributed as evenly as possible throughout the

beam. Preferably, the optimum laser intensity distribution is a smooth curve with

minimal peaking at the center of the beam and little astigmatism, such as shown in

Figure 2. As such, the maximum value of the laser intensity is just below the MPE

value given above.

The second design problem, also related to effectiveness of the laser and eye safety, is control of the maximum power output of the laser over time. If the laser

output power increases, the maximum intensity will exceed the MPE. Conversely, if

the laser output power decreases, the laser's effectiveness will be reduced. Most

eye-safe laser security devices discussed in the parent invention employ

semiconductor diode lasers operating in the red wavelength portion of the light

spectrum. The output power of such semiconductor diode lasers varies significantly

with drive-current fluctuations, temperature, and cumulative use. It is therefore

important to employ a means for controlling the output power to maximize safety and

effectiveness.

The third problem in laser illuminator design for laser security devices is the size of

the unit. Until recently, the relatively large size of laser-producing components have

prevented the use of laser technology in personal protection or security applications.

However, the development of semiconductor laser diodes operating at appropriate

wavelengths and power outputs, and the availability of surface-mounted electronic

integrated circuits for power control, have made hand-held laser security devices

possible. The more compact these components are, the more useful they are to

military and police personnel already overloaded with equipment.

The fourth problem relates to the mechanical stability of both the laser and the

optical system. The position of the laser source relative to the collimating lens must be accurately maintained. The mechanical means for mounting these two

components relative to each other must account for fine adjustment during assembly

(for approximately accurate distancing and alignment between the laser source and

the lens), and subsequently, maintain that alignment during rough use.

The fifth problem is control of the heat generated by the laser diode, the cooling

subsystem and the electronic circuits. These three sources combine to produce

several watts of waste heat which must be conducted away from the temperature-

sensitive semiconductor laser diode. In larger laser systems, a fan could be

employed for that purpose. However, in compact, hand-held laser security devices,

heat sinks should be employed to provide the necessary thermal management.

Moreover, the compact nature of the hand-held laser security devices must be taken

into account, since the temperature rise is inversely related to heat sink volume.

The final problem is the desire to maximize the psychological and physiological

impact that the laser security device imparts to the adversary. Field tests have

demonstrated that a round, uniform, red laser beam (e.g., one to two feet in

diameter) which is directed towards or shined upon an adversary's chest provides a

strong psychological impact. If the engagement is escalated by moving the beam to

the subject's eyes, the physiological response of the eye to such bright light hinders

further action. Moreover, it is deemed desirable to have the laser beam quickly or repetitively flash on and off. Studies have shown that a frequency of 7 to 9 Hertz is

optimal for inducing disorientation in a person.

The present invention resolves these design issues by providing a laser illuminator

that integrates the optical, laser, power control, and thermal management means

into a single, small, compac (or, modularized) unit. The present invention also

employs a novel fiber optic means for producing a smooth, relatively flat beam

intensity distribution to optimize effectiveness and eye-safety. The present invention

is suitable for use in any embodiment of the eye-safe laser security devices

described in the referenced patent and will enhance their effectiveness, safety, and

usefulness. The present invention also provides a sealed module that is easily

replaced when it fails, or upgraded to an improved design based on new

technological advances.

Accordingly, it is an object of the present invention to provide a single, compact,

high-powered laser illuminator module to succeed the separate optical, laser, power

control, and thermal management subsystems in prior art laser security and/or

illumination devices.

It is a further object of the present invention to provide a self-contained laser

illuminator module having a fiber-optic means for converting the sharply peaked, highly elliptical, astigmatic output beam from a semiconductor laser diode into a

relatively smooth, uniform, circular laser beam suitable for effective use in an eye-

safe laser security device.

It is also an object of this invention to provide a laser illuminator module having a

means to flash the laser beam on and off at a nominal rate of 8 Hertz to provide

disorientation and added psychological impact to the adversary.

It is also an object of this invention to provide a laser illuminatormodule having a

mechanical means for adjusting the alignment of optical components to achieve

optimum output of the laser illuminator which also serves to maintain that alignment

during use.

It is also an object of the present invention to provide a smaller, light-weight,

portable laser illuminator module through compact integration of electronic control

means required for operation.

It is also an object of the present invention to provide a laser illuminator module

having a means to protect the semiconductor laser diode from damage due to

overheating through a novel heat sink design and an integral, self-resetting thermal

fuse. Summary of the Invention

The present invention is a laser illuminator for producing a laser beam to provide

warning and/or visual impairment. The laser illuminator includes electronic control

means, a fiber optic means and a means for mounting. The present invention is ,

designed to be used in a laser security device to generate a laser beam to illuminate

and/or create temporary visual impairment of a potential adversary. In the preferred

mode, the present invention is powered by a power source within the laser security

device to provide a visual deterrent to an adversary which results in hesitation,

delay, distraction, surrender or retreat. The means for mounting provides a seal

against external moisture and dust to protect internal components and is preferably

dimensioned to fit within a laser security device.

Brief Description of the Drawings

Figure 1 is a graph illustrating the intensity profile through the two axes of a

semiconductor laser output beam identifying the laser's high peak intensity and the

elliptical beam shape;

Figure 2 is a graph illustrating the intensity profile of the laser output beam from the

present invention identifying a smooth intensity profile and circular beam shape;

Figure 3 is an exploded view of the laser illuminator of the present invention; Figure 4 is a cross-sectional view of the laser illuminator of the present invention

depicting the relationship of various elements as assembled;

Figure 5 is a graph illustrating optimum fiber optic cable length employed by the

present invention;

Figure 5a is a detailed cross sectional view of several fiber optic cable assembly

components of the present invention;

Figure 6 depicts variable distance "a" between the laser diode and the gradient

index lens, and distance "b" between the gradient index lens and one end of a fiber

optic cable, all of the present invention;

Figure 7 is a graph illustrating the effect on the gradient index lens on the output

performance at variable distances "b" as depicted in Figure 6;

Figure 8 illustrates the thermoelectric cooler power supply circuit of the present

invention;

Figure 8a illustrates the means for controlling a laser diode's power of the present

invention; Figure 8b illustrates the means for electrically timing of the present invention that

provides flashing at a rate of 8 Hertz after 10 seconds of continuous operation;

Figure 8c illustrates the laser socket board circuit diagram which serves as an

interface between the laser diode and the remaining three circuit boards; and

Figure 9 shows the preferred embodiment of the present invention when employed

within a laser security device.

Description of the Preferred Embodiments

The self-contained laser illuminator 10 of the present invention is shown generally in

Figures 3 and 4. As seen in Figure 3, laser illuminator 10 includes means for

mounting 21 , fiber optic means 31 and electronic control means 41 in optical

communication with fiber optic means 31.

Means for mounting 21 includes laser illuminator casing 13 and casing base 15.

Preferably, laser illuminator casing 13 and casing base 15 are constructed of hard

anodized aluminum for strength, durability, shock resistivity and resistance to

environmental hazards. Additionally, laser illuminator casing 13 is preferably sized

so as to fit within a specific laser security device's housing, such as a flashlight or a

baton. Means for mounting 21 has a tapered portion 23 at one end, a plurality of threaded screw holes 25₁...25_n at the other end, and further, has an internal

passageway 27 longitudinally formed therethrough. Within passageway 27 is placed

O-ring 29, plano-convex collimating lens 22 and forward fiber optic mount 24,

respectively. Within passageway 27, O-ring 29 sits on a lip (not shown) internally ,

formed within laser illuminator casing 13 near its tapered portion 23. In this

placement, O-ring 29 prevents plano-convex lens 22 from exiting means for

mounting 21 through tapered portion 23. Forward fiber optic mount 24 is a

cylindrically walled structure having at least one internal channel 24a formed

therethrough. Casing base 15 is coupled to forward fiber optic mount 24 on a first

end, and is adapted to support plano-convex lens 22 within passageway 27 at its

second end. Forward fiber optic mount 24 is sized to receptively fit within internal

passageway 27.

The function of collimating lens 22 is to reduce the spread angle of emitted laser

beam 26 to a desired size. Collimating convex lens 22 is preferably adapted to

produce a 50 millimeter focal length laser beam 26. A plano-convex lens is a

preferred collimating lens over an aspheric lens because aspheric lenses are

expensive and do not provide acceptable laser beam focusing in the near field. As

depicted in Figures 4 and 9, when the present invention is operated, a resulting laser

beam 26 emerges from laser illuminator 10. Because laser beam 26 exits laser

illuminator 10 with a wide divergence angle, collimating lens 22 is required to reduce the spread of laser beam 26. Collimating lens 22 is focused by adjusting its position

to provide a laser beam spot diameter of approximately 50-100 centimeters at the

location of an intruders, typically 100 meters away. As laser light 26 emitted from

laser diode 38 is highly divergent, collimating lens 22 is required to collimate laser _..

beam 26 so that a useful spot size (e.g. 10-50 centimeters) can be projected on the

intended target. A conventional short focal length (approximately 50 millimeters),

plano-convex lens is available from a number of commercial optical suppliers

(including Newport Corporation in Irvine, California, Model Number KPX082) and is

sufficient, although multi-element lenses may be used in some applications.

Fiber optic means 31 includes fiber optic cable 33 having a first end 33a and a

second end 33b (as seen in Figure 5a), a fiber optic cable retainer 35, a fiber optic

rear mount (or, button) 37 and a fiber optic spool flange 39 having an internal

corridor (shown generally as item 39a in Figure 3) formed therein. Securely

attached to fiber optic cable first end 33a is first ferrule connecting means 32

adapted to adjustably connect the fiber optic cable first end 33a to button 37. Fiber

optic cable first end 33a is securely attached to first ferrule 32 by a modified SMA-

905 connector 33c. In similar fashion, attached to fiber optic cable second end 33b

is a second ferrule connecting means 34 adapted to adjustably connect the fiber

optic cable second end 33b to the forward fiber optic mount base 24 through

internally threaded aperture 24a. Fiber optic cable second end 33b is securely attached to second ferrule 34 by a modified SMA-905 connector 33d.

Because output laser beam 26 is initially emitted from laser diode 38, the initial laser

beam is elliptical and spreads much more in one axis than the other; typically 10

degrees in the narrow axis and 40 degrees in the wide axis (as illustrated in Figure

1). Therefore, a gradient index lens is necessary to compensate for this

phenomenon. At fiber optic cable first end 33a and within first ferrule connecting

means 32 is coupled gradient index lens 36 (shown generally in Figure 4). An

example of a preferred gradient index lens is Model Number SLW-180-029-063

manufactured by NSG America, Inc. In the preferred mode, any resulting laser

beam 26 emitted from laser illuminator 10 must be optimized depending on several

considerations, including the power output of laser diode 41, the type of gradient

lens 36 used, the distance from the laser beam output from gradient lens 36 to fiber

optic cable first end 32 and the proper alignment of fiber optic cable 33 within

forward fiber optic mount 24. As seen in Figure 6, manufacturing of the present

invention results in a potentially variable first distance between laser diode 41 and

gradient index lens 36 (identified as distance "a") and a fixed second distance

between gradient lens 36 and fiber optic cable's first end 33a (identified as distance

"b"). To accommodate manufacturing tolerances, distances a and b are dependant

upon one another in optimizing the characteristics of any emitted laser beam 26. As

such, in the preferred embodiment seeking to generate a resulting laser beam 35 centimeters in diameter at 50 meters, a 2.2 millimeter distance a between the

gradient lens and the fiber optic cable's first end 32 is deemed quite acceptable.

Employing approximately a 2.2 millimeter distance allows for manufacturing

tolerance adjustment to optimize performance characteristics. To obtain the desired

distance a, fiber optic rear mount 37 includes an internally threaded aperture

adapted to receive first ferrule 32 which is externally threaded. In order to obtain the

proper distance a between gradient index lens 36 and laser diode 38, first ferrule 32

is screwed into fiber optic rear mount 37. Fiber optic rear mount 37 is then attached

to fiber optic spool flange 39 loosely by conventional attachment means (e.g.,

screws) for proper adjustment of gradient index lens 36 in the x, y and z coordinate

directions. To adjust gradient index lens 36 so that it aligns with the output of laser

diode 38, a plurality of adjustment boreholes 39b are formed in the fiber optic spool

flange 39. Screws are then inserted into boreholes 39b to adjust gradient lens 36 in

the x and y directions. Adjustment in the z direction is executed by screwing (or

unscrewing) first ferrule 32 into (or out of) fiber rear mount 37. Once the desired

positioning of gradient index lens 36 is achieved, fiber rear mount 37 is then

securely attached to fiber optic spool flange 39.

Preferably, fiber optic cable 33 is a hard clad 200 micron core fiber having a

numerical aperture equivalent to approximately 0.48 and 70 centimeters in length.

As seen in Figure 5, a 70 centimeter length is deemed sufficient to provide optimized mode mixing, which results in uniform laser beam output. Because of its extended

length and because of the limited space available in fiber optic spool flange 39, it is

convenient to wind fiber optic cable 33 within fiber optic spool flange corridor 39a.

When corridor 39a retains fiber optic cable 33, it is useful to employ fiber cable

retainer 35 to assist in retaining the fiber cable as it is being inserted into corridor

39a.

Electronic control means 41 includes laser diode 38, O-ring 43 and means for

electronically controlling 45, all enclosed within cylindrical shell 47. Shell 47 further

has an internal vestibule 47a longitudinally formed therethrough, and at one end is

securely attached to flanged external housing base 12. In some applications of the

present invention, the natural environment leads to extremely high temperatures. In

such environments, the thermo-electric cooler efficiency is poor, and because of the

size of the present invention, there is a limited amount of heat sink capable of

drawing heat away from the electronics. Therefore, due to the amount of heat

potentially generated by the electronic circuits in electronic control means 41 , shell

47 is preferably constructed of copper material, which acts as an efficient heat sink

to thereby dissipate heat, and, after installation of the electronic circuit boards 45, is

filled with a heat-conducting, high specific heat epoxy material (such as available

from Tra-Con, Inc., Bedford, MA, Stock Number BC-2151). Laser diode 38 is the primary component of electronic control means 41. Preferably,

laser diode 38 is a single component having the laser diode, a photodiode (to sense

the optical power from the laser), a thermo-electric cooler and a high resist

thermistor (to sense the laser diode temperature) all in the same diode package.

Preferably, laser diode 38 is a continuous-wave semiconductor diode laser that

emits visible laser light at wavelengths from 630 nanometers to 660 nanometers at

power ranges of 25 to 250 milliwatts. Laser diode 38 is also adapted not to exceed

the MPE limits for laser safety for up to a quarter second of constant laser emission

at ranges exceeding six meters. Laser diode 38 is capable of projecting a laser

beam diameter of 35 ± 5 centimeters at 50 meter range, the resulting laser beam

being collinear with the axis of laser illuminator 10 to within half of the beam

diameter at 50 meter range. Commercial laser diode units available which meet

these requirements include Model SDL-7422-H1 (manufactured by Spectra Diode

Labs, Inc. in San Jose, California) and the 650-200-T3 (manufactured by Applied

Optronics Corp. in South Plainsfield, New Jersey). Although shorter laser

wavelengths (e.g. orange, yellow, or green colors) would be more effective at

producing glare and flashblind, semiconductor diode lasers capable of producing

these wavelengths at 0.015 to 2.0 watts of power are not yet commercially available.

Limited power versions (less that 5 milliwatts of light output) of such lasers have

been produced in the laboratory, and should be commercially available in higher

powers within 5 years. As those skilled in the art will appreciate, future advances in this laser technology will improve the effectiveness of all embodiments of this

invention are within the spirit and the scope of the present invention.

As a alternate embodiment to employing a semiconductor diode laser, a continuous-

wave frequency-doubled neodymium-YAG laser could be used. These commercially

available lasers (such as those from Santa Fe Laser Corp., Model C-140-D), employ

an infrared semiconductor diode laser to energize a neodymium-YAG rod thus

producing laser light in the green portion of the wavelength spectrum (532

nanometers), which is optimum for producing the flashblind and glare effects. Those

skilled in the art will appreciate that wavelengths ranging from approximately 400

nanometers to 700 nanometers (approximately the visible portion of the wavelength

spectrum) can be employed to induce the effects of glare or flashblind. While this

particular laser diode component does not currently exist in the dimensions required

in the present invention, those skilled in the art will appreciate that it (and similar

laser diodes) may be miniaturized in the future and still be within the spirit and scope

of the present invention.

As seen in Figure 4, electronic control means 41 includes four separate electronic

subassemblies: laser socket assembly 42; thermoelectric cooler supply assembly

44; laser diode supply assembly 46; and timing circuit 48. Each subassembly is a

separate circuit board, the orientation of which is trivial so long as each subassembly is in electrical communication with each other and with fiber optic means 31. In

turn, electronic control means 41 is connected to a power source by power bus 68

which is also in electrical communication with an on/off switch of the laser security

device in which the laser illuminator is mounted.

As seen in Figure 8c, the first electronic assembly is laser socket assembly 42,

which includes capacitor C11 to limit high frequency voltage across laser diode 41

and Schotky diode D11 to protect laser diode 38 from reverse bias voltages.

As seen in Figure 8, the second electronic assembly is thermoelectric cooler supply

assembly 44, which supplies power to the thermoelectric cooler (built into the laser

diode package) and which maintains the temperature of laser diode 38 and a laser

thermistor (built into the laser diode package) at low temperatures. Thermoelectric

cooler supply assembly 44 also contains voltage feedback electronics 44a to control

the electrical output current of the switching power supply 44b: in particular, the

voltage feedback electronics 44a is adapted to monitor the thermistor's (located with

the laser diode package) resistance. If the resistance on the thermistor decreases,

then the voltage feedback electronics 44a drops below 1.25 volts and thereby

controls switching power supply 44b to increase output current. Conversely, if

voltage feedback electronics 44a increases beyond 1.25 volts (representing higher

thermistor resistance), voltage feedback electronics 44a controls switching power supply 44b to decrease output current. Moreover, thermoelectric cooler control

circuit 44c is designed to reduce the current to the switching power supply 44b when

heatsink thermistor TH21 senses temperatures of less than 30° C.

The third electronic assembly is laser diode supply assembly 46 as seen in Figure

8a, which includes laser diode power supply circuit 46a to supply power to laser

diode 38, laser current control circuit 46b and laser disengage circuit 46c. Laser

current control circuit 46b controls the electrical output current of the laser diode

power supply circuit 46a: in particular, the laser current control circuit 46b is adapted

to monitor the laser diode's 38 photodiode current (the photodiode current is directly

proportional to laser diode output power). If the photodiode's current decreases,

then laser current control circuit 46b drops below 1.25 volts and thereby controls

laser diode power supply circuit 46a to increase output current. Conversely, if

photodiode's current increases, laser current control circuit 46b controls laser diode

power supply circuit 46a to decrease output current. The purpose of laser diode

supply assembly 46 is to maintain a constant power output from laser diode 38.

Laser disengage circuit 46c (as seen in Figures 8a and 8b) is designed to turn off

the laser power supply when the input voltage to laser diode supply assembly 46

drops below 3.75 volts nominal. The 3.75 volts threshold level is purely a design

choice adapted to correct any fluctuation in the laser current control circuit and is not a means of limitation.

The fourth electronic assembly is timing circuit 48 (as seen in Figure 8b). Timing

circuit 48 includes a fixed time circuit 48a, a flicker circuit 48b, a thermal switch F41

and power input connections P41 and P42. Fixed time circuit 48a, in the preferred

embodiment, is a ten second one shot circuit. When power is applied to the laser

diode 38, fixed time circuit 48a allows continuous power to be applied for ten

seconds. If laser diode 38 is engaged for more than ten seconds, flicker circuit 48b

engages to turn power laser diode 38 on and off repetitively at a rate of 8 Hz until

power to laser diode 38 is disengaged. Thermal switch F41 is preferably set so that

if the heatsink and electronics temperature of the laser illuminator 10 rises above

60° C, it disengages all power in the electronic assemblies to thereby protect laser

diode 38 from high temperature operation. In the preferred embodiment, time

circuit's 48a circuit board is also formed with a plurality of access holes to allow

access to the laser assembly potentiometer for adjusting the laser optical power

after all electronic assemblies are interconnected.

As those of skill in the art will also come to realize, electronic control means 41 can

also be encapsulated with epoxy (or similar electrically insulative, thermally

conductive material) to prevent tampering with any electronic component and to

provide additional heat sink mass. Moreover, electronic control means 41 is preferably adapted to operate in extended temperature ranges, be powered from

rechargeable battery sources, be capable of controlling power consumption for

extended operation of the present invention, automatically turn off at extended high

temperature ranges, be resistant to shock or vibration and be resistant to

environmental hazards such as moisture. Because of the internal space available in

laser illuminator 10 (for example, approximately 1.36 inches), the electronic control

means 41 is also designed to take up as small a space as possible in all axial

directions. Thus, the electronic circuitry, in the preferred embodiment, is designed to

be stacked, electrically interconnected circuit boards having surface mount electrical

components on both sides of each circuit board. While four separate electronic

assemblies in the electronic control means 41 are disclosed, those of ordinary skill

will realize that similar electronics can be implemented in similar designs, even at

miniature scale, and therefore, the preferred mode is disclosed as an example and

not as a means of limiting the scope of the present invention. Moreover, although

sub-miniature electronic component technologies, such as surface-mount

technology, are disclosed, the preferred embodiment is based on commercially

available components and are not a means of limitation.

Figure 9 illustrates the present invention when employed within flashlight laser

security device 51. In this embodiment, flashlight 51 is an elongated housing

structure adapted to internally receive laser illuminator 10. Flashlight 51 further includes on/off switch 53 which is in electrical communication with both power

source 52 and power bus 68 of electronic control means 41. Lens 22, shown in the

preferred embodiment of Figures 3 and 4, has been replaced by a larger lens 22a

appropriate to the flashlight laser design.

When the flashlight laser security device 51 utilizing the present invention is in

operation, an operator of the flashlight first observes one or more suspected

intruders or potential adversaries. The operator aims the flashlight at the body (e.g.,

torso) of one of the intruders and energizes laser beam 26 for a few seconds as a

warning. The intruders will see a large (approximately 50 centimeter diameter) laser

beam 26 illuminating them. If the intruders attempt to move, the operator can follow

them with the visible laser beam by panning the flashlight laser as necessary to

follow the assailant. At this point, it would be obvious to the intruders that they have

been detected and, because the laser beam moves with them, that they are under

observation. All but the most intent intruders will either turn and run, or surrender.

An important issue in physical security applications is early assessment of the

intruders' intent so that the security forces can adjust their response accordingly.

The intruders' response to this initial warning will help with this assessment process.

If the intruders do not retreat or surrender after seeing the unequivocal warning, it is

a likely indication that they are serious intruders who are willing to risk being

physically harmed to accomplish their goal. If the intruders continue towards their goal, the operator engages flashlight 51 (and

thus, engages laser illuminator module 10) by depressing laser activation switch 53

again and aims it at the intruder's eyes. The flashblind and glare effects produced

by laser beam 26 make it more difficult for the intruders to move quickly or to see

any arriving security forces. When looking back towards laser beam 26 during

daylight, it is very difficult to see things in the direction of laser illuminator 10; at

night, it is almost impossible to see anything when looking in the general direction of

laser illuminator 10. If the intruders are armed and choose to engage the security

forces in a gun battle, the flashblind and/or glare from laser illuminator 10 will greatly

reduce their ability to hit specific targets coming from the direction of laser illuminator

10. Naturally, the present invention can be incorporated into various housings such

as a police baton, motion detector or vehicle lighting system, all with the result of

providing warning through illumination and/or visual impairment.

Whereas the drawings and accompanying description have shown and described

the preferred embodiment of the present invention, it should be apparent to those

skilled in the art that various changes may be made in the form of the invention

without affecting the scope thereof.

Claims

ClaimsWe claim:

1. A self-contained laser illuminator module comprising:

a. an electronics means including a laser;

b. fiber optic means in optical communication with the electronics means,

the fiber optic means including a fiber optic cable; and

c. a means for mounting within a laser security device, the means for

mounting including an adjustable collimating lens therein,

the electronics means and the fiber optic means being securely disposed

within the means for mounting.

2. The laser illuminator of Claim 1 wherein the laser further comprises a laser

diode, a photodiode and a thermo-electric cooler and a high-resist thermistor,

all in electrical communication.

3. The laser illuminator module of Claim 2 wherein the lens is a plano-convex

lens.

4. The laser illuminator module of Claim 2 wherein the lens is an aspheric lens.

5. The laser illuminator module of Claim 3 wherein the laser is adapted to repetitively flash on and off at a frequency of approximately 7 to 9 Hertz.

6. The laser illuminator module of Claim 4 wherein the laser diode is a

continuous-wave semiconductor diode that emits laser light at wavelengths,

from 630 nanometers to 660 nanometers at power ranges of 25 to 250

milliwatts.

7. The laser illuminator module of Claim 4 wherein the laser is a continuous-

wave frequency-doubled neodymium-YAG laser at power ranges of 25 to 250

milliwatts.

8. The laser illuminator module of Claim 4 wherein the means for mounting

further includes a casing having an internal passageway longitudinally formed

therethrough and a base, the means for mounting further including an O-ring

disposed on a lip formed within the casing adjacent to the collimating lens

and a forward fiber optic mount coupled to the base.

9. The laser illuminator module of Claim 8 wherein the casing and the base are

formed of hard anodized aluminum.

10. The laser illuminator module of Claim 8 wherein the forward fiber optic mount is a cylindrical structure having at least one channel formed therethrough and

sized to receptively fit within the casing's internal passageway.

11. The laser illuminator module of Claim 10 wherein the fiber optic means further

comprises a fiber optic cable retainer disposed adjacent to the fiber optic

cable, a fiber optic rear mount adjacent to the fiber optic cable retainer, a fiber

optic spool flange adapted to receive and couple with the fiber optic rear

mount in adjustable relation, and a gradient index lens disposed within the

fiber optic spool flange.

12. The laser illuminator module of Claim 11 wherein the fiber optic cable further

comprises a first end and a second end, the first end further coupled to an

externally threaded first ferrule connecting means which is adapted to

adjustably connect the first end to fiber optic rear mount, the first end being

coupled to the gradient index lens, and a second end, the second end further

coupled to an externally threaded second ferrule connecting means which is

adapted to adjustably connect the second end to the forward fiber optic

mount.

13. The laser illuminator module of Claim 11 wherein the fiber optic rear mount

further includes an internally threaded aperture adapted to receive the first ferrule.

14. The laser illuminator module of Claim 11 wherein the fiber optic spool flange

further comprises at least one adjustment means for adjusting the gradient

lens in a predetermined coordinate axis.

15. The laser illuminator module of Claim 13 wherein the fiber optic cable is a 200

micron core fiber cable having a numerical aperture of approximately 0.48

and a length of approximately 70 centimeters.

16. The laser illuminator module of Claim 4 wherein the electronics means further

includes an electronics base attached to a shell having an internal vestibule

formed therethrough, the electronics means further including a second O-ring,

means for electronically controlling the laser and a power bus in electrical

communication with the means for electronically controlling, all disposed

within the vestibule.

17. The laser illuminator module of Claim 16 wherein the shell is constructed of

copper-based material to dissipate heat.

18. The laser illuminator module of Claim 16 wherein the means for electronically controlling further comprises a laser socket assembly, a thermoelectric cooler

supply assembly, a laser diode assembly and a timing circuit, all in electrical

communication.

19. A device to reduce or temporarily impair the visual ability of a human by either

glare or flashblinding without long-term visual impairment, said device

comprising:

a. an outer housing;

b. a self-contained laser illuminator module positioned within the housing,

the illuminator module further comprising electronics means including a

laser, fiber optic means in electrical communication with the electronics

means and including a fiber optic cable, and a means for mounting

including a collimating lens therein, the electronics means and the fiber

optic means being in optical communication and being securely

disposed within the means for mounting;

c. a switch disposed upon the housing; and

d. a power source disposed within the housing, the power source being in

electrical communication with the switch and the electronics means to

engage the device.

20. The device of Claim 19 wherein the outer housing is a flashlight housing.

21. The device of Claim 19 wherein the outer housing is a baton housing.

22. The device of Claim 19 wherein the outer housing is a security system

housing.

23. A method of employing a laser illuminator module within a laser security

device in adversarial conditions, the method comprising the steps of:

a. providing a laser security device having a laser illuminator module

therein, the laser illuminator module including a laser adapted to emit a

laser beam at wavelengths from 630 nanometers to 660 nanometers at

power ranges of 25 to 250 milliwatts;

b. initially observing one or more suspected intruders or potential

adversaries;

c. aiming the security device at the intruder;

d. engaging the security device by energizing the laser beam to produce

a large diameter illuminating laser beam;

e. continually monitoring the intruder by panning the laser beam at the

intruder as the intruder moves;

f. if necessary, further energizing the laser security device by aiming the

laser beam at the intruder's eyes should the intruder continue to advance;

inducing upon the intruder a flashblind or glare effect so as to make it

difficult to view in the direction of the security device.