Abstract: A slit mechanism for use in a monochromator which is capable of changing not only the slit width but also the slit height. The slit mechanism is provided with a plurality of pairs of slits formed in a disk rotatable about an axis. The two slits in each pair have the same width and the same height, and each pair of slits have a different width from those of the other pairs of slits. The slit mechanism is further provided with at least one additional pair of slits having the same width as the width of, and a different height from the height of, a predetermined pair of the plurality of pairs of slits. All the pairs of slits are arranged circumferentially of a circle on the disk concentric with the axis of rotation of the disk, so that each pair of slits are positioned diametrically opposite to each other on the circle so as to serve as an entrance and an exit slit, respectively, for the monochromator.

Abstract: A spectrophotometer which can be used selectively as a single-beam and a double-beam type and comprises a light source, a monochromator, a chopper mirror for causing the monochromatic light beam from the monochromator to alternately advance along a first and a second path, in which a reference and a sample cell are disposed respectively, a beam combiner for causing the alternate beams to advance along a common path leading to a photoelectric detector, and a mirror movable for selective positioning in and out of the monochromatic light beam between the monochromator and the chopper mirror.

Abstract: A spectrophotometer which uses as a detector a silicon photocell and a phototube sensitive to short wavelengths. The light from the sample cell is divided into a smaller and a larger portion. The smaller portion is projected onto the silicon photocell and the larger portion, to the phototube. The two outputs are combined and amplified for indication. The whole of the light transmitted through the sample cell may also be projected to the phototube while the spectrophotometer operates in the short wavelength region and alternatively to the silicon photocell while the instrument operates in the long wavelength region.

Abstract: Densitometer for quantitative determination of the content of a sample spot on a TLC plate or the like, wherein dualwavelength zigzag scanning is conducted on the spot. Light reflected and transmitted by the sample is received by photometers, and compensation based on Kubelka-Munk's theoretical equations is made on the photometer output so that the output is substantially proportional to the quantity of the substance in the spot being scanned.