1. Throwing light on the body or a part or into a cavity for diagnostic purposes. 2. Lighting an object under a microscope. [L. il-lumino, pp. -atus, to light up]
- axial i. the transmission or reflection of light in the direction of the axis of an optical system. SYN: central i..
- central i. SYN: axial i..
- contact i. i. of the eye by means of an instrument in contact with the cornea or bulbar conjunctiva.
- dark-field i. a procedure in which a black circular shield is used to block the majority of the vertically directed rays of light ( e.g., the field is dark), and a circumferential, suitably angled, mirrored surface is used to direct the peripheral rays horizontally against the object, thereby reflecting the light vertically through the objective lens and along the optical axis; thus, the object is well illuminated in a contrasting dark background. SYN: dark-ground i..
- dark-ground i. SYN: dark-field i..
- direct i. an i. in which the rays of light are directed downward, almost perpendicularly onto the upper surface of the object, which reflects the rays upward into the optical system. SYN: erect i., vertical i..
- erect i. SYN: direct i..
- focal i. i. in which a beam of light is directed diagonally to an object so that it is brilliantly illuminated while the surrounding area is in shadow. SYN: lateral i., oblique i..
- Köhler i. a method of i. of microscopic objects in which the image of the light source is focused on the substage condenser diaphragm and the diaphragm of the light source is focused in the same plane with the object to be observed; maximizes both the brightness and uniformity of the illuminated field.
- vertical i. SYN: direct i..
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il·lu·mi·na·tion il-.ü-mə-'nā-shən n
1) the action of supplying or brightening with light or the resulting state
2) the luminous flux per unit area on an intercepting surface at any given point called also illuminance
il·lu·mi·nate il-'ü-mə-.nāt vt, -nat·ed; -nat·ing
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il·lu·mi·na·tion (ĭ-loo″mĭ-naґshən) [L. illuminatio] 1. the lighting up of a part, cavity, organ, or object for inspection. 2. the luminous flux per unit area of a given surface; its SI unit is the lux. Symbol E>.Medical dictionary. 2011.