Transcription
Kohler (Koehler) IlluminationLarry Johnson, PhD.ProfessorVeterinary Integrative BiosciencesTexas A&M UniversityCollege Station TXVIBS Histology YouTubehttps://vetmed.tamu.edu/peer
Kohler IlluminationKöhler illumination is a method ofspecimen illumination used fortransmitted and reflected lightoptical microscopy. Köhlerillumination acts to generate aneven illumination of the sampleand ensures that an image of theillumination source is not visible inthe resulting image. WikipediaKöhler illumination reduces eyefatigue with long microscope use.
Kohler illumination(order is important)1. Focus specimen2. Close field diaphragm3. Focus condenser4. Center condenser5. Open field diaphragmCondenserFocusingknobFielddiaphragm
Kohler illumination1. Focus specimen2. Close field diaphragm3. Focus condenser4. Center condenser5. Open field diaphragm
Stage position adjustment mage focusing knobsField diaphragmControl knob
Kohler illumination1. Focus specimen2. Close field diaphragm3. Focus condenser4. Center condenser5. Open field diaphragm
Place slide on the stagewith the labelled side up
Kohler illumination1. Focus specimen2. Close field diaphragm3. Focus condenser4. Center condenser5. Open field diaphragm
Viewing edgeIn viewbut out of focusFocus image withfine focus knobIn viewand in focusNote: It is very important forthe image to be in focus duringthe alignment procedure;however, do not use the imagefocusing knobs after the imageis focused in the first step.
Kohler illumination1. Focus specimen2. Close field diaphragm3. Focus condenser4. Center condenser5. Open field diaphragm
Close opened field diaphragmField diaphragm is closed
Kohler illumination1. Focus specimen2. Close field diaphragm3. Focus condenser4. Center condenser5. Open field diaphragm
Sharp edges ofthe diaphragmindicate focusof condenseron the fielddiaphragm.FocuscondenserViewing edgeLight comingthrough ofopening ofdiaphragmOpen field diaphragm tothe viewing edge to usethe viewing edge as areference to center thecondensed light.When diaphragmopening is concentricwith the viewing edgethe condenser iscentered.CentercondenserOpen field diaphragmjust outside of view
Viewing edgeLight comingthrough ofopening ofdiaphragmCentercondenser
Sharp edges ofthe diaphragmindicate focusof condenseron the fielddiaphragm.FocuscondenserViewing edgeLight comingthrough ofopening ofdiaphragmOpen field diaphragm tothe viewing edge to usethe viewing edge as areference to center thecondensed light.When diaphragmopening is concentricwith the viewing edgethe condenser iscentered.CentercondenserOpen field diaphragmjust outside of view
Kohler illumination1. Focus specimen2. Close field diaphragm3. Focus condenser4. Center condenser5. Open field diaphragm
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illumination source is not visible in the resulting image. Wikipedia Köhler illumination reduces eye fatigue with long microscope use. 1. Focus specimen 2. Close field diaphragm 3. Focus condenser 4. Center condenser 5. Open field diaphragm Kohler illumination (order is important) Field diaphragm Condenser Focusing knob. 1. Focus specimen 2 .
