Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
1994-07-05
2001-06-05
Yaminitzky, Marie (Department: 1774)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S068000, C428S076000, C428S173000, C428S201000, C428S913000, C250S461200, C250S484400, C250S486100, C250S487100, C427S157000, C427S419100
Reexamination Certificate
active
06242114
ABSTRACT:
1. BACKGROUND OF THE INVENTION
a. Field of the Invention
The present invention relates to so-called fluorescence references which are useful for checking the operation of fluorescence measuring apparatus used in applications such as medical diagnostic technology.
b. Description of the Related Art
Fluorescent materials are used as detection media in areas such as analytical, medical and biological testing or characterization. In fluorescence, a material absorbs light energy and subsequently loses some of that energy by emitting light at a characteristic, and often different, wavelength. In general, detection techniques are structured around a specific reaction or interaction that changes the intensity of a fluorescent signal in relation to the presence of a material of interest.
One exemplary application of fluorescence is a test procedure for approximating the concentration of a given antibody in a patient's body fluid using fluorescent-tagged antigens which are specific to the antibody. A sample is prepared which contains the patient's body fluid and fluorescent-tagged antigens. When light of a suitable wavelength is applied to the sample, the fluorescent material will absorb this light and emit characteristic fluorescence at longer wavelengths. If antibodies are present, they will bind with the tagged antigens. The interaction is designed to change the fluorescent signal proportionally and, depending on the type of interaction, the change will be either an increase or a decrease in signal. Therefore, observing the change in the fluorescence gives a direct correspondence to the concentration of the antibodies in the fluid. Signal intensity graph
5
of
FIG. 1
illustrates the situation when the signal is increased.
As is well known, fluorescence references are used to check the accuracy of fluorescence-measuring apparatus or instruments.
Common references for fluorescence measurements are organic dyes, which are dissolved to specific concentrations in solvents. The organic dye solution is contained, for example, in cuvettes or dripped into the wells of a test card. The available solvent-dispersed organic dye references do not maintain stable fluorescence values over time and, being liquid, are relatively difficult to shape, handle and store.
As described in the following patents, non-liquid fluorescent materials have been used in control applications. For example, SU patent 1,751,825 describes the combination of a luminophor layer with aluminum and metal oxide absorption layers used in the production of cathode ray tubes. The absorption layer is used to control gas transfer rather than correct light amplitude. Two patents, U.S. Pat. No. 5,021,327 and U.S. Pat. No. 4,865,944, describe different designs incorporating filters and/or fluorescent layers to improve and control radiographic film exposure. This is a significantly different application from fluorescence referencing, and involves X-ray conversion to visible light rather than UV-visible-IR control. U.S. Pat. Nos. 4,975,619 and 4,921,727 describe coatings and the use of coatings on phosphor particles themselves to control triboelectricity rather than optical properties. In their most relevant aspects, the above patents relate directly to: (a) the production of cathode ray tubes (CRTs) or phosphor screens, rather than fluorescence references; (b) the control of physical properties for easier handling, rather than spectral regulation; and (c) conversion of energy for more efficient and uniform exposure of radiographic silver halide films, rather than referenced sources of fluorescence.
2. SUMMARY OF THE INVENTION
In one aspect, the present invention is embodied in a thin film composite for controlling fluorescence intensity, comprising: an optically clear base or substrate of material such as fused silica, glass or plastic; a layer comprising solid fluorescent material such as an inorganic phosphor, formed on the base by wet chemical transfer, including spinning, dipping, or settling, by plasma spraying, or by other suitable techniques; and a spectrally selective filter formed on the base and optically coupled to the fluorescent material-containing layer for modifying the intensity of either or both the excitation or emission spectra of the fluorescent material.
In another aspect, the filter is designed to attenuate or affect the transmission of light in discrete regions of the UV-visible-IR spectra to regulate the specific absorption and/or emission bands of the fluorescent material.
Preferably, the filter is an environmentally stable, dielectric: filter comprising coatings of oxides or nitrides of metals such as silicon, tantalum, titanium, zirconium, etc..
Preferably, a clear polymeric or plastic hardcoat protective layer or coating is formed on or encases the layer of fluorescent material to provide increased environmental durability to high temperature and humidity conditions and durability to cleaning and handling. Also, the device may be covered by a thin pieces of material such as clear plastic, fused silica or glass, to further enhance environmental durability to high temperature and humidity conditions and durability to cleaning and handling. Alternatively, this microsheet cover or “slip” can be bonded over the fluorescent material (with or without the hardcoat) for improved durability.
In yet another aspect, the composite fluorescent device according to the present invention is incorporated in a reference device for fluorescent measurement instruments. In one specific embodiment, discrete filters having the same wavelength characteristics but different transmittance amplitudes in the fluorescence emission region, can be combined with the fluorescent material to form a set of fluorescent references that span several orders of magnitude in detected signal. Alternative to this emission attenuation approach, the filters can be designed to control the excitation amplitude of the fluorescent material, or combined emission and excitation modification filters can be used.
The use of stable solid fluorescent materials such as inorganic phosphors and the use of filters comprising stable materials such as dielectrics eliminate the thermal and time-dependent deterioration associated with organic dyes and metallic neutral density filters. However, in some instances, it may be more important to use the identical dye of the diagnostic test, rather than a more stable, but different, inorganic fluorophore. In such instances, coatings of organic dyes could be formed end protected using techniques similar to those described here. This is an alternative, but more limited, embodiment. In addition, solid materials and references allow easier handling, shaping and storage than liquid references. The use of excitation and/or emission modification provides great flexibility in measurement and instrumental fault detection. The application of such materials to fluorescence reference devices satisfies a long-felt, recognized need in the medical diagnostic and analytical instrument technology.
REFERENCES:
patent: 4039838 (1977-08-01), DiPiazza
patent: 4661704 (1987-04-01), de Leeun et al.
patent: 4865944 (1989-09-01), Roberts et al.
patent: 4921727 (1990-05-01), Datta et al.
patent: 4975619 (1990-12-01), Datta et al.
patent: 5021327 (1991-06-01), Bunch et al.
patent: 5039490 (1991-08-01), Marsoner et al.
patent: 5422489 (1995-06-01), Bhargava
patent: 5670375 (1997-09-01), Seaton et al.
patent: 1751825 (1992-07-01), None
Brown Lindsey
Hendrix Blain J.
Shinkle Michael W.
Yamamoto Glenn K.
Yamasaki Nancy L. S.
Optical Coating Laboratory
Workman & Nydegger & Seeley
Yaminitzky Marie
LandOfFree
Solid fluorescence reference and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Solid fluorescence reference and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Solid fluorescence reference and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2499119