BACKGROUND OF THE INVENTION

1. Pi.*.Id of invention

This invention relates to a device which uses refractive and fluorescence means to intensify, 1) phαtophαsphαrescence in a fiber marker with luminescent properties for use in marking systems and 2) fluorescence to create an emissions detector for laser or light dispersion flux fields.

2. Description of the Prior Art

The prior art using material with phαtophcsphorescsnce to create luminescent markers has involved incorporating a phosphor in a synthetic resin such as polyethylene Susuke - 3,903,055) to form tiles, plates and spheres for use as inserts to form a luminous marker. This method of using phosphors for luminescent markers has the disadvantage of being an inefficient use of the phosphor.

The method common to the trade of making material for luminescence markers by incorporating a phosphor in a binder and forming this luminous material into shapes, such as tiles, plates and spheres, is not an effective use of the phosphor. An example of this method is the use of a calcium sulfide phosphor in a polyethylene binder to make a resin composite. Inserts made of

this resin composite, in the form of tiles, are used to create a luminous road marker by embedding the tile in or to the pavement.

The advantage noted in the prior art is thai, it provides continuous luminous action through the exposing of new luminescence material as the marker abrades. However this method is not effective and is a disadvantage because phosphors are very detrimentally affected by moisture, salts and acids normally associated with weathering.

What occurs on the surface of "this type of luminescence marker, on exposure to weather, is the lass by errosian of the phosphor particles in direct contact with the surface. The depth of moisture penetration into the luminescence marker will depend on the permeability of the binder resin used and how effective the individual phosphor particles are encapsulated within the binder. Interconnection between the phosphor particles will promote deep penetration of moisture through capillary action.

The moisture creates an opaque screen of inactivated phosphor particles between the marker surface and the underlying effective phosphor particles. This opaque screen is a boundry condition resulting from the direct exposure of the phosphor-resin composite to weather. The abrading of the surface will only result in the cαns-umption αf the marker and the inward movement of the opaque screen.

The phosphor inef iciency arise from the interference in the transmission of photons across the boundary between the phosphor molecules in the luminescence marker and the exposed marker surface. For photophαsphαrescence to occur, the phosphor molecule

must be excited by visible or invisible light, a photon. After a delay, the phosphor molecule emits a photon at a longer wave length than the exciting photon. Obviously the emitted photon must be in the visible light region of the electromagnetic spectrum to be useful as a marker to the public. Therefore, the material between the emitting phosphor molecule and the surface of the marker must be translucent to permit the passage of light. The interference with the transmission of the exciting and emitting light to and from the active phosphor particles by the opaque screen of weathered material in exposed phosphor-resin composite inserts is one cause resulting in the ineffective use of the phosphor in markers of this type.

Interference to the transmission of the excitation energy and the luminescence is also created by the active phosphor particles which are opaque. The prior art has attempted to minimize the loss of translucency due to the opaque nature of the phosphor particles by using a transparent binder. One prior art method is the form a suspension of phosphor particles in a clear acrylic ester resin deposited on supporting sheets. <Hinson 3,005, 103). Another prior art method is the use of small spheres coated with a phosphorescent material to activate fluorescent pigments in a transparent binder to provide a reflective colored return at night. <de Veries -3,253,146) (Gravisse - 4,208,300)

Use αf a clear binder to suspend the phosphor over a reflective film, or as phosphor coated spheres in a transparent binder, is the current commercial method of minimizing the opaque effect of phosphor. The method is to arrange the phosphor

particles in a suspension to provide light pathways that enhance the return of the emitted light by clear binders and reflective backing film. Older methods simply maximize the amount of phosphor particles in the exposed surface.

In both approaches, the net effective emission surface is approximately half the surface receiving the excitation energy. To illustrate, consider a perfect uniform layer of phosphor one molecule thick on a horizontal plane being bombarded from overhead by photons that supply the excitation energy. The direction of the emission photons will be completely random, with the result half the emitted photons will travel below the horizontal plane, and half the emitted photons will emerge above the plane. The photons emerging below the plane can be directed by reflection back through spaces in the phosphor layer, but not through the phosphor molecules because of the opaque characteristic of the phosphor. The limiting effect in the production of luminatiαn arises as more passageways are created to permit the return of the backscatter photons emitted below the plane, less phosphor molecules are available to generate the photons being reflected. Therefore, current commercial luminescent markers have the disadvantage of either losing half the emitted light to internal absorption by the marker body, or only capturing part of the excitation energy because αf the need for creating -voids in the phosphor surface to allow passage of the reflected light back in the direction αf the marker sur ce.

Another disadvantage of prior art is the lack αf mechanism to intensify the photophαsphorsence luminatiαn. Note that in this

invention, phosphorescence is used to denote photons emitted by a molecule's electron return from a triplet state to the ground state. In general, phσtophosphoresence is delayed light emission associated with a change in electron spin. Fluorescence is the photon emitted by a molecule's electron return tα the ground state from the singlet state.

Phosphorescence lumination is characterized by very low light intensities. For example, a zinc sulphide phosphor luminance one minute after excitation is 0.17 candles/m2<c/m2) and 0.001 c/m2 after 30 minutes. For comparison, the luminance from a clear sky is approximately 3200 c/m2 and from white paper in moonlight is 0.03 c/m2. The prior art has no provisions for increasing the intensity of the phosphor luminance which results in photαphosphorescence markers being useful primarily in night adapted vision situations.

Laser emission is characterized by a small diameter intense beam of photons with the same wavelength. The intensity of the laser beam makes detection a simple technical matter using a photoelectric detector cell based on amorphous silicon, monocrystal silicon or gallium-arsenic. However, the small cross- sectional area αf the laser beam would require many detectors to assure a reason probability of detecting a rogue laser beam. For example, a blue-green laser passing thru water near a submarine would likely never be detected using know methods of prior art, because in the known prior art, the photoelectric surface must be in direct contact with the laser beam and also protected from damage by the intense laser flux αf photons. This required

protection αf the photoelectric surface αf necessity reduces the detector' s sensitivity tα the faint flux of dispersion photons scattered by the water, or air as the laser beam travels through the media.

Obviously, the laser photons can excite a luorescent material with an excitation band in which the laser emission wavelength falls. In my invention, a fluorescent material that the laser emission can cause to fluorescence is referred to by the symbol of LEF-Dye.

SUMMARY OF THE INVENTION

Accordingly, the primary general objects αf my invention is tα provide an improved linear lenses and luminescent marker which will eliminate .the disadvantages of the prior art. The invention can best be visualized as a thin cylinder of photophαsphαrescent phosphor or a fluorescent dye CLEF-Dye3, with an excitation band matched to the emission wavelength of the dispersion photon flux tα be detected, within an optical waveguide and/or containing an optical waveguide. The optical clear waveguides contain a fluorescence material with an absorption spectrum matched to the photophσsphorescent phosphor's or CLEF- ye] emission spectrum. Fluorescence reemissiαn at a longer wavelength of the absorbed phosphor's αr CLEF-Dye3 emission permits a fraction of the phosphor's or LEF-Dye emission energy to enter trapped modes within the waveguide. By successive internal reflection within the waveguide the phosphor's αr LEF-Dye emission energy <photαns) travel to the waveguide's edge.

One specific object is to eliminate the loss of the

phosphor's emission photons by internal absorption in the phosphor layer. The phosphor layer thickness is restricted to that depth of phosphor molecules that allows the excitation energy to reach the bottom layer of phosphor molecules. The thinness of the phosphor layer permits the emission photons tα exit either outward into the surrounding waveguide or inward into the contained waveguide.

Another specific object of my invention is to minimize blocking of the excitation and emission light by both an opaque screen αf weathered phosphor—resin material and the phosphor cylinder. The optical clear cladding and waveguide core provide substantial protection tα the phosphor layer from moisture and other weathering effects. The outer waveguide provides multiple path ways for the excitation energy to enter into an array αf luminescent fiber markers. The incident excitation radiation is bent by the natural lens effect of the circular waveguide and refraction and reflection at the cladding and core interface of the waveguide. Fluorescence means can be added to the cladding material to aid scatter of the incident radiation energy into the phosphor layer. This scattering of the incident excitation radiation permits a number of stacked phosphor cylinders in an array to become excited.

Another object of my invention is to increase the surface αf the active phosphor with respect to the area αf the fiber marker. Obviously in the prior art, the max phosphor surface is the plate, tile αr sphere's surface. By using a cylinder shape the phosphor surface becomes greater than the plane surface of the fiber marker. The ratio αf the active phosphor surface tα the plane area

of the overall fiber marker is pi C ^* >7 ^* ) times the sum of the inner phosphor cylinder radius and outer phosphor cylinder radius divided by the outer radius of the fiber. The phosphor layer has two emission surfaces, the outer and the inner , due tα control of the phosphor layer depth with respect to the excitation energy. The ratio can range from 2 to 5, therefore a fiber marker will have an active phosphor surface 2 tα 5 times greater than the plane area αf the fiber marker. The ratio is termed L SI in this application.

The unique ability αf a pho ophosphorescence phosphor tα stare certain electromagnetic radiation energy and release the stored energy as useful luminescent is essentially a surface event as noted in the description αf prior art. One advantage of this invention is the multiplication of the active phosphor surface per unit of the device's plane surface. An array of four layers αf fiber markers will create an active phosphor surface αf ten to sixteen times the exposed surface area of the stacked fiber markers. The flux of emission photons available from such an array with sufficient recharge time will be approximately ten to sixteen times the lux from current prior art methods for a given phosphor excitation energy and unit surface area.

Another abject of my invention is to increase the intensity αf the phosphor αr LEF-Dye luminance. Circularily cylindric waveguides using fluorescence emission tα rescatter the photons into trapped modes will capture 10 to 30 percent of the phosphor αr LEF-Dye emission in the waveguide. The multiplication of the photon flux trapped in the waveguide is a cumulative linear

_ Q _

process. For example, the area of phosphor or LEF-Dye surface contributing emission photons in the waveguide, per unit of waveguide length, is the ratio L SI αf the phosphor αr LEF-Dye surface to the plane area of the fiber marker and the trapping effectiveness of the waveguide. Using the marker fibers diameter as the unit of length and a phosphor/waveguide surface ratio [S] of 2.5, for an example, the phosphor surface area supplying emission photons is 2.5D*D/D. If 10 percent of the phosphor emission photons are successfully trapped within the inner and outer waveguide, the net area of phosphor surface per fiber diameter length, adding emission photons tα the waveguide flux is 0.25D ^Λ 2. This is equivalent tα a phosphor emission area equal to 25 percent the plane area αf the fiber marker being concentrated in twice the area αf the waveguide cross section; in effect a linear coaxial lens for the phosphor's emission surface. The double area is because the photons can travel in either direction after being scattered into a trapped mode, thereby two cross section areas. The ratio of the areas are the ratio CS3*<fiber outer diameter)*<fiber length) divided by two times the fibers overall cross section area. The symbols C*] denotes multiplication and C ~] denotes exponentiation in this specification.

The ratio of emission surface to waveguide cross section shows that the multiplication of phosphor αr LEF-Dye luminance is directly proportionate tα the length , the trapping efficiency and inversely proportional to the waveguide diameter. The length is limited by transmission loss in the waveguide material and the device in which the invention is used. For example, a fiber

marker in highway paint the length would be less than.1 ", and as a further example as a guide marker on a door the length could be several feet αr hundreds αf feet in an antenna. The diameter is limited by manuf cturing technology with a current lower limit αf approximately 10 mils. The trapping efficiency is a function of the refractive index ratio for the waveguide core and cladding material. Therefore the invention can be configured to multiply the phosphor or LEF-Dye luminance intensity several thousand times.

BRIEF DESCRIPTION OF THE DRAWING Figure la is a partially sectional perspective view and Figure lb is a cross sectional view of a luminescent fiber marker incorporating the invention,

Figure 2a is an exposed perspective view of a four layer array αf luminescent fiber markers wrapped into a cylinder shape with various end devices, and Figure 2b

Figure 3 is a perspective view of a directional marker, and Figures 4 and 5 are views αf an LEF-Dye detector and cross- section αf the device configuration.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now tα Figure 1, the luminescent fiber marker <14) is shown with the cylinder αf phosphor CIO) within an optical waveguide region C12) and containing an optical waveguide region <11). The inner <11) and outer (12) waveguide material may be the same, different αr the same material with cladding layers (9) tα create separate zones <24, 25, 26, 27, 28, 29); however, if

different material is used, the material must have compatible physical and chemical properties.

The outer waveguide <12) is shown circular, but in an array can be a slab or plate type planer waveguide. The cladding layer (9) and outer waveguide region 12) on the outer surface of the phosphor cylinder CIO) permits creating an array of phosphor cylinders containing inner waveguides within a slab type dielectric waveguide by providing pathways far the exciting incident radiation to reach the lower phosphor layers.

The material for the waveguides Cll, 12) and cladding C9) is an optically clear material with respect to the incident radiation wave length 13) that provides the excitation energy tα the phosphor C7) , the photophosphorescence emission radiation wavelength C8) and the fluorescence reemissiαn C31, 41, 51) from the contained fluorescent material C30, 40, 50) as shown in Figure 1. The cladding will have a lower refractive index than the waveguide core material. The waveguide and cladding material may be a soda glass, crown glass, silica glass, dense barium flint glass, lanthanum flint glass, flint glass, acrylic polymer methylmethacrylate, polystyrene, polycarbonate, methylacrylate styrene copolymer, allyldiglysol carbonate, pαlymethylpentane, styrene acrylonibrile, fluσrαcarbαn resin, FEP flurαplastic, polyvinylidene fluoride, polymethyl methacrylate fluorinated polymer,pαlymides, polyαlefins, pαlysulfones, polysilαxαnes, cellulose acetates, polypropylene terephthalate, polyethylene terephthalate, polyethylene isσphtalate, polyvinylidene chloride, or other suitable material that becomes commercially available and

apparent to those skilled in the material art for performing the equivalent function.

The waveguide material contains a fluorescent substance C30) having the ability to absorb the emission radiation from the phosphor or LEF-Dye and re-emit C31) the absorbed light to effect an internal scatter of the radiation to permit trapping within the waveguide cores. The fluorescence is randomly re-emitted in all directions within the waveguide, with a fraction of the reemission photons having an angle of incidence to the waveguide-cladding interface, greater than Snell's law αf reflection critical angle of incidence for the respective indexes of refraction for the waveguide core Cll) and (12) and the cladding C9) material.

The ratio αf trapped energy C E3 to the initial scattered energy is approximately RE=1-ARCSIF Ccladding index of refraction/core index of refraction) or RE=0.08 to 0.25. Commercially ^" available plastic material will allow core-cladding combinations that can trap 0.08 to .13 of the fluorescence from a efficient fluorescent dye. High refractive index flint glass such as Schαtt SF 57 with terbium oxides as the fluorescent centers have a potential RE of .24.

Rare-earth oxides of samarium Csm202), eruαpiuπ CEu203), and dysprosium CDy203) combined with high index flint and soda glasse offer favorable excitation and emission spectra for fluorescent waveguides. Molycαrp Application Report 7001 " THE USE OF RARE- EARTH OXIDES TO GIVE COLOR OR VISIBLE FLUORESCENCE TO SODA-LIME GLASSES'* describes examples of fluorescence glass. The material i available from Molybdenum Corporation of America, 280 Park Ave.

_— J 1. "5 _—

Few York. Hew York 10017. _^ Inorganic ions chromium, neodymi and itrium can also be used tα create fluorescent centers in glass.

Polycarbonate or pαlymethylmethacrylate have lower refractive indexes than available flint glasses with a consequently lower ratio of trapped energy; however, a wide selection of organic luorescent dyes are commercially available from Pylam Products Co. , Sun Chemical Co. , Allied Chemical, Shannon Luminous Material, Day Glo Corp. , Radiant Color, Cleveland Pigment and Color Company, Uniform Color Company, Eayer and other commercial sources which offers a means αf increasing the ratio of trapped phosphor emissions. Many fluorescent dyes have narrow absorption and emission bands widths of <5 ^' run separated by 60 tα 100 nm that permit matching two, three or four progressively longer wavelength emission to absorption bands. Each fluorescence event allows 0.08 to 0.13 αf the remaining untrapped emissions to be scattered into angles αf incident permitting capture within the waveguide sane. This multiple fluorescent scattering cascade is cumulative and can trap 20 to 30 percent of the phosphor's emission phαtαns.

TABLE 1

WAVE LENGTH RANGE IN nm l

I MATERIAL EXCITATION EMISSION |

I Fluorescent 1 F-Dye #1 550 600 1 1 F-Dye #2 480 550 1 1 F-Dye #3 <430 480 1

1 Phosphor #1 300-500 550 1 1 Phosphor #2 <400 440 1

Table 1 list' classes of material grouped by their excitation and emission spectra. Referring tα Table 1 and Figure 1, phosphor #2 C7) with emissions in the blue-violet C8) excites F-Dye #3 (30) in the middle zone C28) of the outer waveguide region C12) and the inner most zone C24) of the inner waveguide region Cll) . The F-Dye #3 emissions C31) excite F-Dye #2 C40) in the outer C29) and inner C27) zones αf the outer waveguide region C12) and the middle C25) zone of the inner wave guide Cll) region. This permits all of F- Dye #3 C30) untrapped emissions to pass through zones containing F-Dye #2 C40) and allow excitation αf F-Dye #2.

F-Dye #1 C50) is added tα the zones C24) and C28) containing F-Dye #3 C30) and the outer zone C26) αf the inner waveguide region (11). This permits all of F-Dye #2 (40) untrapped emissions Cil) in the inner waveguide region Cll) to pass through zones containing F-Dye #1 and in the outer waveguide region C12) to pass through the zone C28) containing F-Dye #1.

F—Dye #3 must be separated from F-Dye #2 to prevent absorption and rescattering of trapped F-Dye #3 emissions by F- Dye #2, however, since F-Dye #1 excitation region is outside F-Dye #3 emission spectrum the two fluorescent dyes can share the same waveguide zone. Bands of cladding C9) are used to create the separation within the waveguide. The cladding is chosen from a material transparent to phosphor and fluorescent dyes emissions and with a lower refractive index than the waveguide core regions. The multiple separated fluorescence scattering events trap 2Q to 30 percent αf the phosphor emission energy. Clearly the same procedure can be used with high refractive index glass with

fluorescent centers for even greater trapping efficiencies αf the phosphor emissions by the waveguide.

The prior art uses the fluorescent dyes series in which the emission of the shorter wavelength dye is matched tα the absorption band of the next longer wavelength fluorescent dye to increase the amount αf solar energy captured in fluorescent waveguides. The dyes are either placed together in the waveguide CZewail etal Patent 4,227,939] αr placed in separate layers CMauer etal Patent 4,149,902] optically bonded to form a composite waveguide. The patents are cited for reference tα illustrate the essential difference between maximizing the capture αf a phosphor or LEF-Dye emission used by the invention and the method prior art uses to maximize the capture of the solar flux.

The photon cascade involving two or more fluorescent dyes absorbs more αf the solar flux than one dye can due tα the wavelength specific nature αf a fluorescent dye and the fact the solar flux has many wavelengths present. Energy emission from the shorter wavelength CF-Dye #3, for example) αr first dye in the cascade event, is shifted to the next longer wavelength dye CF-Dye #2, for example) excitation wavelength, which adds to the same wavelength energy also present in the solar flux. In effect the second dye CF-Dye #2) receives a double amount αf energy in its excitation energy range which is emitted at a longer wavelength. However, a phαsphαr, laser αr fluorescent dye emission is approximately equivalent tα a single wavelength, sα only a series of shifts to longer wavelengths αf the phosphor or LEF-Dye emission energy is accomplished by a optically unseparated

fluorescent dye cascade waveguide. The last fluorescent dye longer wavelength) is the only fluorescent event that scatters the phosphor, laser or solar flux emissions into trapped modes within the waveguide. All the emission from the first dye F-Dye #3 is absorbed by the second dye F-Dye #2, allowing for fluorescent efficiency, because the second dye cannot distinguish between emission photons from the first dye that are in a trapped mode and the untrapped phαtαns. Therefore the last fluorescent dye emissions can be the only scattering event that causes trapping αf the incident radiation energy. However, by partitioning the waveguide with cladding layers into waveguide zones in which the fluorescent dyes are separated, the invention separates the shorter wavelength dye trapped photons from the next longer wavelength fluorescent dye, but allows the next dye in the cascade to still be excited by the untrapped emission photons from the first dye. This separation and protection αf the trapped photons emitted by each fluorescent dye from being absorbed and rescattered by another fluorescent dye, allows use αf multiple fluorescent dyes to increase the amount αf phosphor emissions trapped within the device.

The phosphor emission energy in the device C 14] is trapped in six waveguide zones with three different wavelength spectrums. If a single dominate wavelength is desired, a diffuser ring C18), as shown in Figure 2, made of the waveguide core material with a outer circumferential layer of cladding material and containing F- Dye #2 and F-Dye #1, is placed at the end αf the waveguide C14) αr array C17) tα convert the shorter wavelengths to the longer

wavelength of the F-Dye #1. For markers to have good visibility, the final fluorescence emission should be under 610nm to fall favorably within the human eye's spectral response spectrum.

Examples of material referred tα in Table 1 are:

Phosphor #1 Hanovia Glo Pigment Series 1000 Czinc sulfide with double activators)

Phosphor #2 a) ZnZr03 with neodymium activator b) Nb+Zn2Si04 with manganese activator* c) CaS with antimony activator*:

F-Dye #1 a) Thiαindigo pigments CI Vat Red 1 and CI Vat

Red 41 b) Heledon pink PR-109 c) Radiant R105,R106 and R-203-G d) Rhodamine B

F-Dye #2 a) Perinane pigment CI Vat Orange 7 b) CI 753 Phodamin 3G c) Fluorcscein d) Radiant R-105, R-106 and R-203G

F-Dye #3 a) Terephthalic acid, 2, 5-dehydr. αxydiethylester b) 12H-phthalαperin-12-l c) Radiant R-105 d) Disazα CI 508 Dianil Blue G

* denotes information from Fluorochemistry by Jack De Ment, Chemical Publishing Company, Brooklyn, New York, 1945.

The phosphor material choice will depend on the luminescent fiber marker application and the required photαphαsphαrescence emission characteristics desired. The phosphor will be one or a combination αf halides, oxides, silicates, sulfides, sulphates and other compounds of barium, cadmium, calcium, magnesium, strontium, niobium and zinc with an activator- of bismuth, copper, cerium, eruopium, lead, antimony, silver, samarium, manganese, uranium, yttrium, thulium, terbium and neodymium or combinations thereof.

Many phosphors with photophosphαrescent properties are commercially available. For example, Hanovia phosphorescent

pigment P1000 will provide satisfactory photαphαsphαrescence in the luminescent fiber marker according tα this invention.

The phosphor layer CIO) should be of sufficient depth and density to present a uniform phosphor surface to the excitation energy C13) , but not sα thick as tα prevent internal emission phαtαns C8) from escaping into the waveguide Cll). In addition, the phosphor layer shields the fluorescent dyes in the inner waveguide from damage by incident ultraviolet.

One preferred embodiment, CD shown in Figure 1, is a 30 mil diameter marker using polycarbonate or polystyrene Cn=1.59) with C. I. Vat Red 1, Heledαn pink PR-109, Radiant R-203G, Xanthene derivative Eosine C. I. Vat Red 87 αr C. I. Vat Red 41 added at the ratiα of 10" -3 to 10" -5 by weight of polycarbonate or polystyrene to provide fluorescence that absorbs light of about 550- nm wavelength and emits light of about 590 n . The phosphor is a nσntαxic zinc sulfide phosphorescent P-1000 sold by Hanovia with an emission spectrum centered near 550nm. The cladding material C9> is a fluorinated polymer Cn=1.40).

The preferred embodiment is formed by a combination of cσextrusiαn, phosphαi—resin composite powder coatings thermal, solvent and αr ultraviolet cured, glass core-cladding preforms heat drawn into fibers and or cylinders, surface finishing, coating and fiber layering methods well known to and commercially available from those skilled in the manufacturing αf optical fibers and composite sheet material.

Referring again to Figures la and lb, the outer radius C4) is 15 mils, the cladding C9) is 1 mil, the outer phosphor layer

radius C3) is 10 mils and the inner radius C2) is 8 mils. The ratio αf phosphor area to waveguide area is pi * C 10+8] /15 or approximately 3.75. The ratio αf trapped energy tα the initial scattered energy is 1-arcsin (1.4-0/1.59)"-or 0.119 and with a fluorescence efficiency of .85, a trapping effectiveness of approximately 0.10 is created. Therefore, the net area αf phosphor surface adding emission photons to the waveguide flux is .375 D per unit of waveguide length. The multiplication αf photon flux is .375 D Clength of waveguide) /Cpi*CD) "2/4)*C2) σr .75 L/pi CD) less transmission losses in the waveguide.

Referring tα Figure 2, a single fiber marker C21) with a length (16) of 1.5 feet, will contain an active phosphor surface of 1.5*C12)*C3.75)*C0.030) or 2.025 square inches of phosphor furfacS; J3y placing the fiber marker .(21) i an array (15 ⁾ with. § depth of four fibers and a radius C22) of 0.75 inches the active phosphor surface is approximately C2 pi)* .75- 75- 4) CO.03) )* 1/2)*C1/.03)*C4)*C2.025) or 1170 square inches or over 8 square feet in a device (17) with a plain surface area of 18*1.5/144 or 0.19 square feet. The intensity of emission is .75*C18)/pi CO.030) or 143 times the intensity from the phosphor's surface. If a retro-reflector C19) is placed an one end C613 of the array marker C17) the light intensity is increased 50 to 60 percent at the other end C62] , which is 220 times the source luminescence from the phosphor. If the embodiment is enlarged from 30 mils to a 60 mils diameter marker, the same array C 17] will contain 9.17 square feet of active phosphor surface. The intensity of the emission at the array's ends C61, 62] will drop from 143 to 82 times the

source phoεphαr luminescence.

This embodiment C17) when equipped with a retro-reflector disk C19) made αf waveguide care material at end C61) and a diffuser disk C18) at end C62) with a parabolic reflector C20) fitted over the array's end C62) and diffuser C18) creates a light beam source. The reflector C20) can be farmed from any light reflecting material, for example, polished aluminum. This device is a non-electric alternate to a small battery powered hand held torch.

This embodiment of the marker fiber array C17) can be used as a flat plate C63) as shown in Figure 3 with the ends C23) shaped as arrow heads with edge diffuser bands C18) for a highly visible non-electrical directional marker. The ends C23) may be any shape required by the marker's purpose. The end C23) material can be optically clear tα the trapped emissions C8, 31, 41, 51), contain fluorescence means to convert the trapped emissions to a single wavelength, and αr reflective and refractive means tα scatter the emissions as a diffuser.

Referring now to Figure 4, the device is configured to trap the scattered photons from a blue-green laser. Layer C200] is an outer protective polymer optically clear to the blue-green photon L 13] and containing the fluorescent dyes t80] [90] and [100] to scatter by fluorescence other wavelength photons that may be present in the incident flux. The dyes in layer [200] minimize the trapping αf energy other than from the laser αr other desired incident energy in waveguides C201], C2023 and [203]. The blue- green phαtαns [13] enters the waveguide [2033 which contains the

fluorescent dye 1 701 F-Dye #2 [referred to as LEF-DyeJ and excites the dye [70] tα emit photons [71] and [ ^' 721 at a longer wavelength. [71] represents the fraction of F-Dye #2 fluorescence trapped in waveguide [203]. The untrapped emissions [72] of dye [70] leave waveguide [203] through the cladding layer [9] and enter waveguide [202] and excite the fluorescent dye F-Dye #1, [80] to fluorescence [81J and [82]. [81] represents the fraction αf F-Dye #1 fluorescence trapped in waveguide [202] interface at an angle greater than the critical angle σf incident for total internal reflection as defined by Snell's law. The untrapped fluorescence [32] passes through the cladding layer [9] into either waveguide [201] or [203] and excites a longer wavelength fluorescent dye [90]. The fluorescent dye [90] can share the inner waveguide C203] with the fluorescent dye [70] because the emission wavelength from fluorescent dye [70] is shorter (therefore, trapped photons [71] are not rescattered by [90] and lost) than the excitation wavelength of fluorescent dye [90]. The cycle can again be repeated with an even longer wavelength fluorescent dye [100] in waveguide [202]. Dye [100] excitation spectrum must be outside αf Dye [80] emission spectrum tα prevent rescattering in waveguide [ 202] of trapped emission photons from the shorter wavelength fluorescent dye [80] by the longer wavelength fluorescent dye [ 100] .

The blue-green photon flux initiates a fluorescent cascade in waveguide [203], Figure 4, that starts with fluorescent dye [70], then fluorescent dye [80] in the next coaxial and co-centered waveguide [202], then fluorescent dye [90] in waveguides [203] and

[2013, then fluorescent dye [100] in ^" waveguide [202] in which up to thirty percent αf the blue-green flux is trapped in the waveguides [201], [202] and [203] by fluorescent scatter. The trapped energy has four different wavelengths with the longest in the deep red αr near infrared. Again, a diffuser [18] Figure 2, can be used to convert the trapped energy into the longer wavelength of the last fluorescent dye [100] . Four dyes are described, but fewer or more dyes can be used: The key tα high trapping efficiencies is to prevent the rescattering of the photons that each fluorescent dye [70, 80, 90, 100] has scattered into angles αf incident allowing trapping in the waveguide cores.

As shown in Figure 5, mαnαcrystal silicon, gallium-arsenic, σr other photoelectric cells can be optically coupled to the end of each fiber C 14] or array [ 15] tα generate a current or voltage rise [252] and [253] proportional to the change in the blue-green laser phαton flux incident on the device. A cross directional array [264] αf fibers [14] using individual photodetectαrs [1803 can be used to create a proximity sensor for a laser flux [250] field by measuring the intensity αf the photαdetectors output [252] and E253] and direction along each axis of the fiber array αf the rate αf change the photαdetectαr output is traveling. A two dimension array [264] is shown, but a three dimensional array can be formed with the addition αf a third set αf fibers [14] and photαdetectors [180] .

While several different embodiments of the invention have been described in detail _^ , it is to be understood that various modifications and adaptations of the invention will be obvious and apparent to those skilled in the art and it is intended that such obvious and apparent modifications and adaptations be included in the spirit and scope of the invention as set forth in the appended claims.