Abstract: A photodetector detects fluorescence emitted from a sample placed on a substrate of a DNA chip. There is an irradiation optical system for guiding irradiation light by a first optical waveguide, gathering the irradiation light by a first lens and irradiating the sample. A reception optical system gathers fluorescence at an input-side end surface of a second optical waveguide by a second lens and guides the fluorescence to a measuring unit. The irradiation optical system and the reception optical system are separate light guiding paths. The reception optical system is of a confocal optical system in which a focal point on the sample is identical to a focal point at the input-side end surface of the second optical waveguide of the reception optical system.

Abstract: Provided is a photodetector 10 for detecting fluorescence 40 emitted from a sample 3 placed on a substrate of DNA chip 1 has an irradiation optical system 11 for guiding irradiation light 25 by a first optical waveguide 21, gathering the irradiation light by a first lens 22 and irradiating the sample 3; and a reception optical system 12 for gathering fluorescence 40 at an input-side end surface 31C of a second optical waveguide 31 by a second lens 32 and guiding the fluorescence 40 to a measuring unit 33. The irradiation optical system 11 and the reception optical system 12 are separate light guiding paths, and the reception optical system 12 is of a confocal optical system in which a focal point on the sample 3 is identical to a focal point at the input-side end surface 31C of the second optical waveguide 31 of the reception optical system 12.

Abstract: An optical system for magnifying a display panel includes a magnifying lens disposed in front of a display panel. The magnifying lens is constructed with two lenses respectively having convex surfaces opposite each other. At least one of the two convex surfaces is aspherical. A transverse aberration of the magnifying lens is less than the diameter of the pupil of an eye at a point where the eye is positioned. The lens for the optical system is a Fresnel lens whose vortex center is located on its edge. An apparatus for magnifying display panels according to the invention includes an instrument to be viewed distantly and instruments to be viewed not distantly. The instrument to be viewed distantly is disposed distant from the Fresnel lens under a center portion of the Fresnel lens, whereas the instruments to be viewed not distantly are disposed close to the Fresnel lens under an edge portion of the Fresnel lens.