In co-operation with the members of Hitachi Ltd., a spectrofluorometer with a Xenon lamp as the light source has beendevised and by this means a regression analysis concerning the relation between thescale values of visual impression and the three chromatic values (α, β and Y) has been made on 53 samples of cloth whitened with various fluorescent agents .An equation for the whiteness derived from the anlysis is given as W1=30.9α-17.9β+20.8Y-1.3217 in which the coefficients are evaluated for calculated W1 values to accord with those given by Judd formula for proximity factor k=20 and for the equation to become applicable to non-fluorescent yellowish region. By developing the equation in lst order terms of X, Y and Z in the neigh-bourhood of the ideal white, a whitereness sensitivity curve -ω1λ is obtained. -ω1λ is defiaed by W1-1.0800=∫λE-ωλγ(λ)dλ where Eλ and γ(λ) are the energy of the light and the intensity ratio of the light from sample to the light from MgO respectively. In non-fluorescent region, there are several whiteness sensitivity curves by known formulas for whiteness; they are however considerably different from one another. Such being the case, if in deriving the whiteness equation mentioned above the approximation is extended to include the term of α2 with anegative coefficient, a better whiteness sensitivity curve could be worked out.
The essential quality demanded of paper used for. originals in diazo copying is the high spectral transmittance in the ultra violet region of 3500_??_4000Å where the sensitivity of diazo paper is the highest. The U. V. transmittance is much influenced by the kinds of pulp and filler as well as the extent of beating. Results of tests made on various kinds of paper are summarized in the following. (1) U. V. transmittance of pure cellulose (cellophane) is very good. (2) The factors that affect U. V. transmittance most are lignin and beating. Paper, well beaten and of a small amount of lignin content, has high U. V. transmittace. (3) Influence of filler differs by the kind of filler. Use of dyestuff makes the spectral trans-mittance selective. (4) The transmittance at 4000Å of paper obtainable on the market is as follows. Tracing paper: 60_??_65%, Thin barayta paper: approximately 20%, Letter paper: approximately 15%.
Polarization characteristic of several types of phototubes is measured by a newly proposed method. An elliptically polarized light is passed through a rotating polarizer and received by a photo-tube. Azimuth and retardation of the light are controlled to compensate for the detrimental effect caused by the polarization characteristic of the phototube to free the photo-current from periodical changes. The controlled amounts of azimuth and retardation needed for this compensation deter-mine the polarization characteristic of the phototube. The polarization characteristic of 931A is not uniform over its photo-surface; its spread ranges from a few to 20%. But, the polarization characteristic of 1 P 28 is uniformly distributed over the whole photo-surface with the magnitude, 1/5 of that of 931A. The head-on type phototube shows hardly such polarization characteristic as mentioned above.
Evaporated aluminium film deposited at oblique incidence of the vapor is known to develop a, coarse surface structure as the thickness or incidence angle increases. The wavelength dependence of regular reflectance, of asymmetry of regular transmittance and of dichroism of the film is, measured with the thickness and vapor incidence angle as parameters, and the structural anisotropy of the film is inferred from the optical anisotropy. The results obtained are as follows: 1. When the r. m. s. surface roughness of the film is sufficiently small in comparison with the wavelength, the roughness can be estimated from the regular reflectance at normal incidence. For example, the r. m. s. roughness of films deposited at 60° incidence and in 35, 40, 55 mμ thickness. is 10, 15 and 20 mμ, respectively. 2. When the vapor incidence angle exceeds 70°, the direction of the growth of crystallites. tends to incline somewhat to the direction of vapor beam. 3. When the vapor incidence angle exceeds 60°, the axial ratio of crystallites oriented in chains. with their long axes perpendicular to the vapor beam becomes above 10 in the evaporation process.
A study is made on the fundamental properties of amplitude filter-the filter that gives an amplitude distribution over the exit pupil-defined by the equation T(s)=as2+(1-a/2) where a is a constant of the value 2_??_a_??_-2. Fraunhofer diffraction patterns obtained with this filter are investigated in regard to the diffraction patterns on the focal plane, the optical transfer function of the slit aperture, and the encircled energy (or total illumination) in the diffraction image. The first two are analytically calculated and the third is evaluated numerically by the use of the Gaussian quadrature method for various values of parameter a.
Light distribution in an image is known to depend not only on the maximum deformation of actual wave-front from an ideal reference surface but also on the type of aberration. Marechal proposed a condition under which a system can be regarded as satisfactorily corrected for any aberration when the normalized intensity (Strehl definition) at the diffraction focus is greater than or equal to 0.8. Under this condition, he derived aberration tolerance values for various aberra-tions (any one aberration or any combination of aberrations). In his treatment of the permissible aberration in optical systems, small aberrations and uniform distribution of amplitude over the entire aperture of the optical system are assumed. In the present paper, study is made as to how the aberration tolerances given by Mar6chal are affected when the amplitude distribution over the entire aperture is not uniform. The problem is in the context of Fraunhofer diffraction pattern of an incoherent point source. The amplitude distribution (amplitude filter) over the aperture is in the form of a paraboloid of revolution, by which the total energy passing through the aperture remains constant and the Strehl definition at the diffraction focus is kept unity when the system is free from aberrations. The results obtained for the effect of the amplitude aperture filter on the aberration tolerances are presented in figures for various aberrations as a function of the amplitude filter parameter. The results also show a close relation between the non-uniform amplitude aperture illumination and the Marechal aberra-tion tolerance values. It is shown what the maximum value of aberration tolerance will be for a given non-uniform amplitude filter and what form of the aperture filter is optimum for use.
In the present paper, two subjects are mainly studied. One is the development of the designing method studied in the previous paper (I). When the merit function of the system is a many variable function of multi-vectors, general formulae for determining the optimum values of system parameters are derived by using generalized maximum step method and generalized secondary approximation theory. By applying this method to multi-layer films (a many variable function of two vectors), optimum values of both thicknesses and refractive indices can be determined simultaneously. The other is the investigation of the convergency of the merit function to an extremum. Although the weakness of the steepest ascent method is that the converging speed is very slow if the hyper surface of the merit function is distorted along a direction of any system parameter, in maximum step method it can be eliminated by testing the signs of components of a direction cosine of the position vector conceived by the line that connects a corrected point on the hyper surface with the next corrected point. Contours of equal merit function of antireflection monolayer are drawn in a diagram taking thickness and refractive index as abscissa and ordinate. A band pass filter consisting of eleven layer films is designed by the generalized maximum step method. As an example of the distorted hyper surface of the merit function, anti-reflection films of triple layer, the weighing function being taken into consideration, are designed also by using the same method. Anti-reflection films of double layer are designed by using the generalized secondary approxi-mation theory.
The depolarization of persistent internal polarization of ZnCdS phosphors is investigated with and without external electric field. After a phosphor layer which holds the pri-polarization PB is subjected to an external voltage V and is simultaneously irradiated by infrared or visible ray, the polarization P is found to be expressed by P=PBexp(-λt)+P∞[1-exp (-λt)] P∞ is determined by the applied voltage, but not by the radiation intensity. λ is a function of the radiation intensity, but not the applied voltage. The formula is interpreted with a model of barrier type polarization. The above depolarization effect was applied to infrared photography with success.