| 摘要 |
PURPOSE:To eliminate the necessity for using a halogen lamp or an electronic flash apparatus having large quantity of light, by constituting the titled apparatus so that the brightness of the specific wavelength region around a measuring part is made high and the measuring part can be clearly indicated by the difference of contrast even if the circumference is light enough. CONSTITUTION:The light emitted from a light projecting element 16 passes through the aperture part 6a of a concave mirror 6 and is converged by a condenser lens 18 to be incident to a focus plate 8 and reflected by the reflective surface 8a of said focus plate 8 while the reflected light is again reflected by the reflective part 6b of the concave mirror 6 to form a ring shaped illumination spot around a measuring part. A finder 22 having wavelength selectivity is provided to a finder 20 and, for example, when a red LED with a specific wavelength is used as the light projecting element 16, a long wavelength transmission type filter for blocking or attenuating the specific wavelength light thereof is used as the finder 22 having wavelength selectivity. When an observing region is observed by said filter, the contrast of the region A corresponding to the observing region and the region B in the periphery of said region A with the illumination spot C becomes large and visibility becomes easy even if the circumference is light enough. |
