Patent Publication Number: US-2003221357-A1

Title: Method and apparatus for timing light emission from an article excited by light radiation

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
     [0001] This application claims the benefit of priority from Provisional Application Serial No. 60/386,662, entitled Method And Apparatus For Timing Light Emission From An Article Excited By Light Radiation, filed on Jun. 4, 2002. Provisional Application Serial No. 60/386,662 is hereby incorporated by reference in its entirety. 
    
    
     
       FIELD OF THE INVENTION  
       [0002] The present invention relates generally to articles of manufacture that are capable of luminescence in response to light excitation, and more particularly to a method and apparatus for effecting light excitation of such articles and that enables the state of light emission from such articles to be timed and monitored from a position remote from the article.  
       BACKGROUND OF THE INVENTION  
       [0003] Articles of manufacture are known that are capable of emitting light, generally termed luminescence, in response to excitation by light radiation. Such articles typically are made in whole or in part of a phosphorescent substance or material capable of delayed luminescence, that is, a luminescence that persists after removal of the exciting light source. Such delayed luminescence is sometimes referred to as afterglow. Such articles may also be made of a non-phosphorescent substrate or base that is painted or coated with a coating containing phosphor, or molded from a suitable plastic having a phosphor constituent mixed with the plastic substrate. The phosphor, when subjected to light radiation, shines or glows in the dark for a length of time related to the time duration of light irradiation, the particular phosphor composition, and the intensity and wavelength of the particular light charging source.  
       [0004] One example of the aforedescribed articles that has become popular with fishermen are fishing lures that have been painted with a phosphor coating or are molded from a plastic having a phosphor constituent mixed with the plastic. When these fishing lures are subjected to or charged by a light source, the excited phosphor creates a glow or fluorescence that may enhance the attraction of fish and, correspondingly, may improve fishing. Techniques employed to excite these lures include exposing them to sunlight, and also directing an incandescent light of a conventional flashlight or lamp on the lures.  
       [0005] A major disadvantage of known techniques for charging or exciting phosphor coated or impregnated fishing lures is that they fail to provide any indication of the state of the radiation charge imparted to the lure. Thus, once a lure is charged, it must be pulled from the water to determine if it is still charged sufficiently to provide the desired luminescence. Accordingly, it follows that a light source for exciting or charging an article of manufacture having a phosphor component by light radiation, such as a fishing lure adapted to absorb light radiation and emit a luminescent light or glow after the charging radiation has ceased, and which light source is capable of providing a time indication of substantially when the luminescence charge on the article has dissipated, would provide a significant advantage over known light radiation techniques employed to charge phosphorescent articles. This is particularly applicable to articles such as fishing lures where it is desirable to provide an indication of the expiration of luminescent light emission at a location remote from the irradiated lure.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006] One of the objects of the present invention is to provide a system for timing the length of light irradiation induced luminescence from an article capable of absorbing radiation from a light source.  
       [0007] Another object of the present invention is to provide a method for determining the state of light emission from an article adapted to emit luminescent light when excited by light radiation.  
       [0008] A still further object of the present is to provide a system for effecting light excitation of an article adapted to emit light when excited by light radiation, the system including a miniature flashlight having a light emitting diode light source operative to emit light of predetermined wavelength so as to optimize irradiation of, and light emission from the article.  
       [0009] A feature of the present invention lies in the provision of a miniature flashlight that may be readily carried on one&#39;s person and that employs a light emitting diode operative to emit a blue light wavelength for light irradiation of a fishing lure or the like having a phosphor coating or internal phosphor constituent.  
       [0010] Still another object of the present invention is to provide a fishing lure and timing light system that includes a fishing lure made at least in part of a material, or having a coating, capable of emitting light for a period of time after being subjected to a source of light irradiation, and a flashlight having a light emitting diode light source, a power source and a switch operable to connect the light source to the power source so as to effect light radiation from the light source, at least the portion of the housing supporting the light emitting diode being made of substantially the same material as the light emitting material or coating used in the fishing lure so at least the diode supporting portion of the housing absorbs light radiation and emits light for the same period of time as the charged fishing lure.  
       [0011] Yet another object of the present invention is to provide a miniature flashlight having a light emitting diode operative to emit light having a wavelength in the blue light spectrum, at least a portion of the flashlight being made of a material having a phosphor constituent adapted to be excited by light radiation from the light source so that observing the termination or reduction of light emission from the flashlight housing provides an indication that the light emitted by an article in response to light irradiation of the article by the light source of the flashlight has terminated or has been reduced so as to require re-excitation by light irradiation.  
       [0012] Further objects, features and advantages of the invention will become apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings wherein like reference numerals designate like elements throughout the several views. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0013]FIG. 1 is a side elevational view of a miniature flashlight constructed in accordance with one embodiment of the present invention;  
     [0014]FIG. 2 is a prospective view showing the opposite side of the miniature flashlight illustrated in FIG. 1;  
     [0015]FIG. 3 is a front end view of the flashlight illustrated in FIGS. 1 and 2;  
     [0016]FIG. 4 is a bottom edge view of the flashlight of FIGS. 1 and 2;  
     [0017]FIGS. 5 and 6 are enlarged perspective views of an article of manufacture in the form of a fishing lure having a phosphor coating or phosphor constituent in accordance with the present invention;  
     [0018]FIG. 7 is a pictorial illustration showing light irradiation the fishing lure of FIGS. 5 and 6 using the miniature flashlight of FIGS. 1 and 2; and  
     [0019]FIG. 8 is a pictorial illustration showing operational use of the fishing lure of FIGS. 5 and 6. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0020] In this written description, the use of the disjunctive is intended to include the conjunctive. The use of definite or indefinite articles is not intended to indicate cardinality. In particular, a reference to “the” object or thing or “an” object or “a” thing is intended to also describe a plurality of such objects or things.  
     [0021] Referring now to the drawings and in particular to FIGS.  1 - 4 , a miniature flashlight constructed in accordance with a preferred embodiment of the invention is indicated generally at  10 . The flashlight  10  is similar in construction to the miniature light emitting diode flashlight disclosed in U.S. Pat. Nos. 6,190,018 (“the &#39;018 patent”) and 6,357,890, and U.S. application Ser. No. 10/066,554, filed Jan. 31, 2002, all of which are assigned to the assignee of the present invention and are incorporated herein by reference. To this end, the flashlight  10  includes a housing  12  having a generally parallelogram shaped peripheral edge profile and is relatively miniature in size so as to be readily held in the palm of one&#39;s hand. The housing  12  has a pair of oppositely facing side panels or walls  14   a  and  14   b , a pair of opposite ends  16   a  and  16   b , and upper and lower edge surfaces  18   a  and  18   b . The end  16   b  of the housing  12  defines a keyring extension formed integral with the housing  12  and defines in part the periphery of a generally triangular opening  20  accessible through a keyring lock  22  hinged to the housing  12 , as is known.  
     [0022] As described in the &#39;018 patent, the miniature flashlight  10  supports a light source in the form of a light emitting diode (LED)  28  preferably at an upper corner of the housing, as illustrated in FIGS. 1 and 2, so that the housing at least partially encloses the LED. The housing  12  further supports a power source internal to the housing that may comprise any type of battery supply with sufficient power to energize the light source, such as a pair of disc-type batteries having flat oppositely disposed sides. Preferably, the power source is comprised of two 3-volt coin type lithium cell batteries that are supported within a power source frame (not shown) internal to the housing  12 .  
     [0023] The LED  28  preferably emits blue light, although the present invention may be carried out with any LED emitting a suitable wavelength of light. As will be described, a blue light LED light provides the desired wavelength for irradiating a phosphor coated article or an article having a substrate that includes phosphorus as a constituent. Most phosphors in luminescent light emitting applications are stimulated or charged only by short wavelength light sources, such as light sources emitting blue to far ultraviolet wavelength light. The blue LED, although producing most of its emission in the visible blue wavelength spectrum, produces a significant light energy level in the invisible or poorly visible shorter wavelengths, and is highly effective in light irradiation of phosphor materials. It has been found that an excellent stimulus for articles coated with a phosphor-containing coating are true ultraviolet LEDs because most of their energy is contained in short wavelength ultraviolet to far ultraviolet invisible light. This is contrasted with white light sources, such as incandescent lamps that emit very little short wavelength light. Thus, the light emission from white light sources contains virtually no ultraviolet light and only an insignificant amount of visible blue wavelength light.  
     [0024] The housing  12  also supports an internal switch structure, such as disclosed in the aforementioned &#39;018 patent, which includes a switch button  32  supported on the housing  12  so as to extend slightly outwardly from sidewall  14   a . The switch button can be depressed to connect the LED light source  28  to the battery power source during depression of the switch button, thus enabling the operator to determine the time period in which the LED  28  emits light.  
     [0025] In its preferred embodiment the housing  12  of flashlight  10  is made of a plastic material commercially available under the trade name Permaglow from Hirotec Engineering Co., Santa Ana, Calif. However, any suitable plastic and/or phosphorous material may be used. The housing  12  is preferably made of a material having a mixture ratio of approximately about 5-15 parts clear plastic pellets to one part glow material, and preferably a mixture approximately 10-13 parts clear plastic pellets to one part phosphor glow material, based on a thickness of material of approximately 0.125 inch. It has been found that this mixture may be subjected to light radiation to effect a glow or luminescent light emission for a period of approximately two to four hours. As mentioned above, this duration of light emission is most effectively established when the LED light source  28  produces a light source rich in the wavelengths of blue, violet, and ultra-violet light. It has also been found that the desired luminescent glow of at least the portion of the housing  12  adjacent the LED light source  28  is achieved when luminescent colorants are added to the plastic of the housing  12 . For example, adding a luminescent colorant additive selected from the group consisting of aluminum oxide, strontium oxide, calcium oxide, europium oxide, and boron oxide to the plastic material of housing  12  significantly enhances the luminescent responsive to radiation from the LED  28 .  
     [0026] The housing  12  differs from the housing disclosed in the &#39;018 patent by having the side walls or panels  14   a  and  14   b  formed integral with the housing and from the same plastic material having a phosphor constituent added or disbursed therein. Alternatively, the housing  12  may comprise a power source frame housing that is adapted to support side panels in the manner disclosed in the &#39;018 patent. To this end, the housing  12  may comprise a two-piece construction as disclosed in the &#39;018 patent. With the latter construction, the side panels may be made of a material different from the material from which the power source frame housing is made, such as being made from an anodized aluminum.  
     [0027] As described above, the flashlight  10  is operative to effect light irradiation of an article adapted to emit light when excited by light radiation. In the illustrated embodiment, such an article may comprise a fishing lure  36 , as illustrated in FIGS. 5 and 6. The fishing lure  36  includes a selectively shaped body  38  in which is embedded a fishing hook  40  having a barbed end  40   a  extending from the rear end of the body, and an eyelet end  40   b  extending from the forward end of the lower body for attaching the lure to a fishing line.  
     [0028] The fishing lure body  38  may be made of a plastic material having a phosphor constituent similar to the material from which the flashlight housing  12  is made, thus being adapted to emit light when excited by light radiation. Alternatively, the fishing lure may comprise a solid substrate, such as clear plastic or other desired material, and have a coating applied thereto that includes phosphor adapted to the excited by light radiation from the LED light source  28  of the flashlight  10  so as to emit luminescent light after being excited by light radiation. With the fishing lure  36  being made at least in part of a material capable of emitting light for a period of time after being subjected to a source of light radiation, such as the blue wavelength light emitted by the LED light source  28 , subjecting the fishing lure to light radiation from LED  28  for a predetermined period of time causes both the fishing lure and at least the portion of the flashlight housing  12  supporting and adjacent the light source  28  to be excited by substantially the same light radiation from the light source.  
     [0029] Note that the fishing lure and the material of the flashlight housing  12  at least adjacent the LED light source  28  have substantially the same light emitting properties because they are formed of or incorporate similar material, or at least material having the same or similar photo-luminescent properties. As shown in FIG. 7, when the LED  28  is energized by using finger pressure to depress the switch button  32 , the light radiation emitted by the LED  28  simultaneously irradiates the fishing lure  36  and the flashlight housing  12 , and irradiates both for the same duration. Although the fishing lure body  38  is irradiated directly by the LED  28 , while the flashlight housing  12  is mostly irradiated indirectly due to reflection and “side-scatter” of light through the LED  28 , the amount of light reaching the fishing lure body and the flashlight housing is sufficient to fully charge each portion. Thus, the fishing lure body  38  and the flashlight housing  12  each will re-radiate light or “luminesce” for about the same period of time, and the level of luminescent light will decay or reduce at about the same rate.  
     [0030] The amount of time that the fishing lure body  38  and the flashlight housing  12  will continue to emit light after being fully charged depends several factors, such as 1) the specific type of luminescent material used, 2) the concentration of such light-emitting material to inert material (which may be expressed as a ratio of light emitting material to non-light emitting material), 3) the length of time to which articles are subjected to the source of light, 4) the intensity of the light source to which the articles are subjected, and 5) the frequency of the light source to which the articles are subjected. The fishing lure body  38  and the flashlight housing  12  may be irradiated, for example, by using the type of LED described in the flashlight of the &#39;018 patent, for an appropriate period of time governed by the above-mentioned factors, to fully “charge” the light emitting material forming the component or incorporated therein. The fishing lure body  38  and the flashlight housing  12  will then emit light for a period of time, again governed by the above-mentioned factors until the level of light falls to a subjectively low level. Such a subjective level is the level that the user deems the fishing lure to be ineffective or otherwise undesirable in attracting fish. This subjective level may vary widely.  
     [0031] After the fishing lure  36  has been charged or irradiated by energizing the LED  28 , the fishing lure may be submerged into a stream, lake, or other body of water for fishing, as shown in FIG. 8. By observing the level of light being re-emitted from the flashlight housing material adjacent the light source  28 , the user may determine when the luminescent light emitted by the fishing lure  36  has ceased or decreased to a sufficiently low level, such as the twenty-five percent level mentioned above, so as to require removal of the fishing lure from the water and re-excitation by light radiation from the flashlight LED  28 . Accordingly, the luminescent light emitted by the flashlight housing  12  essentially provides an indication of the time duration of light emission or luminescence of the fishing lure  36  at a location remote from the fishing lure when the fishing lure is beneath the surface of the water, thus providing a visual indication of the need to recharge the fishing lure by light re-excitation.  
     [0032] Also note that as a convenience to the user, the keyway extension  16   b  of the flashlight  10  in association with the keyring lock  22  permits the flashlight to be readily attached to one&#39;s clothing, such as a fishing vest, shirt, or other article of clothing within eye observation to permit the light excitation of the fishing lure to be readily monitored.  
     [0033] Note that in accordance with an alternate embodiment of the present invention, the flashlight housing  12  need not be formed of a luminescent material. Rather, the fishing lure  36  itself need only be formed of such luminescent material. As mentioned above, the fishing lure  36  may be made at least in part of a material capable of emitting light for a period of time after being subjected to a source of light radiation. Preferably in this embodiment, the fishing lure  36  may be subject to illumination by a blue LED-type light source, such as the light source described in the &#39;018 patent. In this specific embodiment, the fishing lure  36  may be subject to light radiation from the light source  28  for a predetermined period of time so that the fishing lure will continue to re-emit light for a predetermined period of time. For example, the fishing lure  36  may be subject to the light from the light source as described above, and will continue to re-emit light thereafter for a period of time. Further, the light re-emitted by the fishing lure will reduce or decay at a known rate, of course depending upon factors previously mentioned. Thus, the user of the fishing lure may estimate the length of time before the level of reemission of light from the fishing lure falls to a sufficiently low level, for example, to a “twenty-five” percent level, as mentioned above. At that point, the user may retrieve the fishing lure  36  from the water and re-illuminate it to fully “charge” its light emitting capacity.  
     [0034] Specific embodiments of a method and apparatus for timing light emission from an article excited by light radiation according to the present invention have been described for the purpose of illustrating the manner in which the invention may be made and used. It should be understood that implementation of other variations and modifications of the invention and its various aspects will be apparent to those skilled in the art, and that the invention is not limited by the specific embodiments described. It is therefore contemplated to cover by the present invention any and all modifications, variations, or equivalents that fall within the true spirit and scope of the basic underlying principles disclosed and claimed herein.