Increment threshold techniques are widely used in investigating the mechanism of human color-vision. Its various uses are reviewed here. Stiles developed two-color threshold method and obtained spectral sensitivity curves of underlying mechanisms, π1, π2, ……, π5, which were presumed to be: responsible for the color vision. The findings were strongly supported by Rushton's results in which the technique of retinal densitometry was employed. However, the spectral sensitivity curves, derived from the overall sensitivity curves obtained under various adapting conditions by Boynton and Wald did not quite agree with Stiles' results. Further investigations are needed. Summationn index was introduced to analyze the interaction among mechanismsand it appeared that certain mechanisms inhibit with each other along a line of Hering's opponent-color theory. A further development of this method should provide some important data for the study of mechanism of human color vision.
Temperature dependence of persistent internal polarization of ZnCdS phosphors has been stu-died. Measurement of thermally depolarized charges after the polarization shows the presence of electron traps of 0.60 eV and 0.78 eV in depth. This result accounts for the temperature depen-dence of the rate of dark polarization. Also, the experiment indicates that the polarization hass the peakvalue when it occurs at temperatures around 60°C, and above this temperaturethe polari-zation drops to a much smaller value. The characteristics may be explained with a reduced barrier model in consideration of the hole distribution.
In connection with the polarizing interference microscope which incorporates Savart plates1), the theory of interferential-image-transferis formulated by introducing four-coherences between two linearly polarized light beams at pairs of points across a plane. By' Fourier transformation, the distributions of those coherences in image plane are mutually related to the ones in conjugate object plane under partially coherent illumination. This permits to describe analytically the effec-tiveness of source size compensation when the aberrations and finite aperture of the optical system are taken into consideration. Moreover, the expression with regard to coherence transmission of a Savart plategives a complete solution for spatial structure of interference phenomena and clari-fies the fact that a Savart of small lateral shear acts as a pupillary amplitude filter causing diffe-rential interference.
A gas lens of laminar flow type is made with which preliminary experiments is performed. Experiments ascertain that there exists an imaging action in this type of gas lens. Two kinds of experiments are conducted to confirm this action. One is to make real images with a gas lens and another to constitute a telelescope using a gas lens. In the former experiment, real images are produced by changing not only the distance between the gas lens and the imaging plane butalso the temperature. gradient of the gas lens. In the latter experiment, a Keplerian telescope is: made with the use of the gas lens for an object lens and a concave mirror for an eye lens. Fairy good photographs are obtained.
A new method of determining the optical phase distribution in materials based on the double diffraction was reported in previous papers. In this part, several experimental results obtained by this method are described. 1) Instantaneous temperature-gradient distribution in a solid can be shown by color distribu-tion, whereby we can observe the phenomena of heat conduction in material and detect hetero-geneous parts in it by watching the variation of equi-gradient curves of temperature. 2) In the process of fracture of material, the deformation of strained specimen can be shown directly by the color distribution, whereby we can observe the transient phenomena from elastic to plastic deformation, the movement of the region of stress concentration, the relaxation of stress and so on. 3) The two dimensional distribution of refractive index in crystalline lens of rabbit eye is determined. 4) The roughness or waviness of metalsurface can be observed by the color distribution. A new optical system witha white light source and a multiple slit is devised to obtain clearer colored image and to make the analysis easy.
The well-known Maréchal's method for aberration tolerances has been studied only from the theoretical point of view. The purpose of this paper is to outline this method and to apply it to several simple cases of optical system with spherical and parabolic reflectors. A relation between the maximum permissible focal length and the field angle is derived in a functional form with F-number and object distance as parameters. Lastly, the form of the image surface is determined on which the Strehl definition becomes maximum. Only the third order aberration is considered, therefore the range of validity, is limited only to small field angles and large F-numbers.