# US 2004/0200979 A1 · Methods for fluorescence detection that minimizes undesirable background fluorescence > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2004/0200979 A1 - Document ID: US20040200979A1 - Status: Published application - Kind: A1 - Application number: 10/833,425 - Filed: 2004-04-28 - Published: 2004-10-14 - Earliest claimed: 2002-01-23 - Assignees: Applera Corporation - Inventors: Richard T. Reel - Web page: https://patentgrep.com/patent/US20040200979A1 ## CPC - G01N 21/645: {Specially adapted constructive features of fluorimeters} - G01N 2021/6482: {Sample cells, cuvettes} - G01N 2021/6495: {Miscellaneous methods} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract The present invention provides a method for the excitation of a fluorescent sample and the measurement of the fluorescent emission. The method of the present invention has the advantage of significantly reducing the amount of background fluorescence. The method includes the steps of exciting a sample in a substrate with a beam of light that enters the substrate at an angle less than or equal to 45° C., and preferably, less than or equal to 20°, and then collecting the fluorescent emission form the sample with a lens system which focuses the emitted light onto a CCD for detection. Although the following description of the present invention uses a scanning system using channel plates by way of illustration, the method described herein may also be used with non-scanning systems as well as capillary systems. ## Claims ### Claim at position 1 1-28. canceled ### Claim 29 A method for detecting fluorescence from a sample in a channel plate comprising: providing an excitation beam of light to the sample and the channel plate, wherein the excitation beam of light produces a fluorescent trail, wherein the fluorescent trail comprises a first portion from the channel plate and a second portion from the sample; positioning the excitation beam of light to increase the spatial resolution between the first portion and the second portion; and collecting the second portion on a detector. ### Claim 30 (depends on 29) The method as defined in claim 29, wherein the detector is selected from the group consisting of charge coupled devices, CMOS detectors, photodiode, photodiode array, photomultiplier tubes, and photomultiplier tube arrays. ### Claim 31 (depends on 29) The method as defined in claim 29, wherein the excitation beam of light is positioned at an angle less than or equal to about 20° relative to a channel axis. ### Claim 32 (depends on 29) The method as defined in claim 29, wherein a collection optics system collimates the fluorescent trail and refocuses the second portion onto the detector. ### Claim 33 (depends on 32) The method as defined in claim 32, wherein the collection optics further removes scattered light from the excitation beam using a long pass filter. ### Claim 34 (depends on 32) The method as defined in claim 32, wherein the collection optics further removes scattered light from the excitation beam using a band pass filter. ### Claim 35 (depends on 29) The method as defined in claim 29, wherein positioning comprises directing the excitation beam of light substantially parallel to the channel plate into a reflective mirror, which reflects the excitation beam of light into the sample. ### Claim 36 (depends on 35) The method as defined in claim 35, wherein reflecting further comprises directing the excitation beam of light from the reflective mirror through a prism. ### Claim 37 An apparatus for detecting fluorescence from a sample in a channel plate comprising: a light source operable to generate an excitation beam of light, wherein the excitation beam of light produces a fluorescent trail, wherein the fluorescent trail comprises a first portion from the channel plate and a second portion from the sample; a mirror operable to position said excitation beam of light into the sample, increasing the spatial resolution between the first portion and the second portion; and a detector operable to image the second portion. ### Claim 38 (depends on 37) The apparatus as defined in claim 37, wherein the detector is selected from the group consisting of charge coupled devices, CMOS detectors, photodiode, photodiode array, photomultiplier tubes, and photomultiplier tube arrays. ### Claim 39 (depends on 37) The apparatus as defined in claim 37, further comprising collection optics, wherein the collection optics comprises a long pass filter operable to remove scattered light at a wavelength of said excitation beam of light. ### Claim 40 (depends on 37) The apparatus as defined in claim 37, further comprising collection optics, wherein the collection optics comprises a transmission defraction grating operable to separate light into differing wavelengths. ### Claim 41 (depends on 37) The apparatus as defined in claim 37, further comprising a prism operable to direct the excitation beam of light toward the sample. ### Claim 42 (depends on 37) The apparatus as defined in claim 37, wherein the light source is a laser. ### Claim 43 A method for detecting fluorescence from a sample in a channel plate comprising: providing an excitation beam of light to the sample and the channel plate, wherein the excitation beam of light produces a fluorescent trail, wherein the fluorescent trail comprises a first portion from the channel plate and a second portion from the sample; positioning the excitation beam of light to increase the spatial resolution between the first portion and the second portion; and collecting the second portion and substantially smaller amounts of the first portion on a detector. ### Claim 44 (depends on 43) The method as defined in claim 43, wherein the excitation beam is positioned at an angle less than or equal to about 20° relative to a channel axis. ### Claim 45 (depends on 43) The method as defined in claim 43, wherein providing an excitation beam of light comprises providing a laser to generate the excitation beam of light. ### Claim 46 (depends on 43) The method as defined in claim 43, wherein positioning comprises directing the excitation beam of light substantially parallel to the channel plate into a reflective mirror, which reflects the excitation beam of light into the sample. ### Claim 47 (depends on 46) The method as defined in claim 46, wherein reflecting further comprises directing the excitation beam of light from the reflective mirror through a prism. ### Claim 48 A method for detecting fluoresence from a sample in a channel plate comprising: providing an excitation beam of light to the sample and the channel plate, wherein the excitation beam of light produces a fluorescent trail, wherein the fluorescent trail comprises a first portion from the channel plate and a second portion from the sample; positioning the excitation beam of light to increase the spatial resolution between the first portion and the second portion; and collecting the first portion and the second portion on spatially different sections of a detector. ### Claim 49 (depends on 48) The method as defined in claim 48, wherein the excitation beam is positioned at an angle less than or equal to about 20° relative to a channel axis. ### Claim 50 (depends on 48) The method as defined in claim 48, further comprising: providing a light source operable to generate the excitation beam of light; and providing a mirror operable to position the excitation beam of light. ### Claim 51 An apparatus for detecting fluorescence from a sample in a channel plate comprising: a light source operable to generate an excitation beam of light, wherein the excitation beam of light produces a fluorescent trail, wherein the fluorescent trail comprises a first portion from the channel plate and a second portion from the sample; a mirror operable to position said excitation beam of light into the sample, increasing the spatial resolution between the first portion and the second portion; collection optics to collimate and focus the fluorescent trail; and a detector operable to image the second portion. ### Claim 52 (depends on 51) The apparatus according to claim 51, wherein the collection optics are oriented about 90 degrees with respect to a channel axis.