Any device that produces light or heat.
Burton lamp Ultraviolet lamp, including some short wavelengths from the visible spectrum (e.g. Wood's light), mounted with a magnifying lens in a rectangular frame. It is used primarily in the evaluation of the fit of a hard contact lens, in conjunction with the instillation of fluorescein into the eye.
See staining.
filament lamp A lamp in which light is produced by electrically heating a filament, usually of tungsten. The filament is contained in a bulb in which there is either a vacuum or an inert gas. The emitted spectrum is continuous.
See continuous spectrum.
fluorescent lamp Discharge lamp in which most of the light is emitted by a layer of fluorescent material excited by the ultraviolet radiation from the discharge (CIE).
See fluorescence.
halogen lamp A tungsten filament lamp in which the glass envelope is made of quartz and is filled with gaseous halogens. This permits a higher filament temperature and consequently provides a higher luminance and a higher colour temperature as well as a longer operating life than a conventional filament lamp of the same input power. Halogen lamps are used in some ophthalmoscopes and retinoscopes and as very bright sources for people with low vision.
Syn. tungsten-halogen lamp.
incandescent electric lamp Lamp in which light is produced by means of a body (filament of carbon or metal) heated to incandescence by the passage of an electric current (CIE).
See incandescence;
luminescence.
Macbeth lamp A lamp used in testing colour vision. It contains a powerful tungsten filament bulb with a blue filter of specific absorption properties such that it produces a source of a colour temperature of about 6800 K, thus approximating the spectral characteristics of natural sunlight. The lamp is also fitted with a stand to hold the colour vision booklet (Fig. L2).
Syn. Macbeth illuminant C.
See CIE standard illuminants;
pseudoisochromatic plates;
Farnsworth test.
tungsten-halogen l.
See lamp, halogen.


Fig. L2 Macbeth lamp