November 11, 2004
Credit for the invention of confocal microscopy goes to Marvin Minsky - he has the patent, you can read his recollections and it totally failed to make him rich, since the necessary computer power to make it work was unavailable at the time (1957). This Minsky completely failed to address in his later career, by instead choosing to work on artifical intelligence. Oh well. Fast forward to 1986-87, and lasers, microscopy and the personal computer were brought together, to produce a functioning confocal microscope. In conventional fluorescence microscopy, a fluorescent dye (it glows when hit with light of sufficient energy) is introduced into the sample, placed under the microscope, and then the sample is illuminated to induce fluorescence. A filter is used to separate the applied light from the emitted, fluorescent, light. This allows particular details to be highlighted by the dye. However,this doesn't work well for thick samples, since light is also emitted from material lying above and below the focal plane, interfering with the area of interest. In confocal microscopy, a pinhole is used to filter out this extraneous light, by blocking light which does not come from the focal plane of the microscope; only in focus light reaches the detector. It helps to see it drawn, so here's an excellent overview and series of diagrams on the subject. The resulting images exhibit excellent clarity and resolution, and can be combined to generate 3D images or show extremely fine details. more images The N company's microscopy page Canon makes better lenses mind. Pentax deserves more respect! Thank you for your time. Pell, for those of you who are even faintly interested, is an Australian, a Cardinal of the Catholic Church, and thinks that child abuse within the church isn't that big a deal because there is so much abortion going on. Yeah, I'm still spitting.
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What's cool about the confocal technique is that its being used to make optical storage discs, where the laser focuses on different levels inside the disc, upping the storage to hundreds of GB.
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This is a great post, poly, but his name's George Pell.
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Wolof - you're kidding. oh no *bangs head on desk* Thanks Alex - actually, confocal could be rapidly overtaken by multi-photon fluorescence, since that avoids the need for a highly machined pinhole AND the use of high energy photons, which rapidly degrade living tissue. In multi-photon, fluorescence is achieved by delivering multiple photons which sum to the same energy as that needed for single photon fluorescence. So, if one light particle at 350 nm (in the near UV region, sun burn city) can create fluorescence, then two-photon fluorescence would use 2 x 700 nm photons (down in the near infra-red, and much less damaging). The really neat bit is it only works if the photons arrive sufficiently close together in time - it requires a high intensity light beam, and if that is created by focussing a low intensity beam, then fluorescence will only come in the region around the focal point. The effect is the same as confocal microscopy, at least in theory.
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It's ok, polychrome. Let's call him Gergory, just to piss the little fucker off. Or give money to those lovely gay lads that dress as him at the Sydney Mardi Gras.