Vivatech

Other

Haven D Noble

William C Evans

A light source or lamphouse wherein light from lamps 16 of different colors, as obtained by filters 18, is projected into a full diffusing chamber 20 with diffusing reflective internal surfaces where the light is premixed. The diffusing chamber is disposed adjacent to a specular dispersing chamber 22 of greater volume than the diffusing chamber where the light is further mixed and dispersed to provide uniform illumination at an outlet; the use of both types of chambers providing efficient mixing in a limited volume so that the source can be movably mounted on the column of an enlarger or printer.

Light source for photographic color printing

A light source for providing controllable illumination having the red, green, and blue components in selected intensity proportion, uses a lamp/filter assembly which projects light through a diffusing plate into a mixing chamber from the output end of which mixed light is emitted for illuminating photographic paper through a negative. The chamber is rectilinear, and the red and green lamps project toward opposite corners while the blue lamp projects along the axis of the chamber. A light pipe which has an input end facing the output end of the chamber extends into the chamber and extracts light which is processed in red, green, and blue channels having temperature stabilized phototransducer circuitry and control circuitry wherein signals corresponding to the intensity of the color components are processed in the channels and are modified by control signals which can be produced in the photo printer control computer. The control signals, as they may be modified, are compared in each channel with a time-variant, repetitive waveform synchronized to the AC line, which varies in accordance with an anti-log function and which provides control pulses. The control pulses are applied to switching circuitry which controls the power to each lamp. This circuitry thereby compensates for the nonlinearity in the transfer characteristic of the system. The illumination of the photographic paper is therefore accurately controlled.

Light source for photographic color printers

A solar energy collector has a corrugated, inclined plate exposed to solar rays on a blackened front or top side thereof. A heat-absorbing liquid carrier adheres to an opposite rear or undersurface of the plate in the form of a thin sheet by surface tension, and is directed gravitationally to a collection trough at the bottom edge of the plate.

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Mt. Pleasant, IA, United States of America

Haven D Noble