Patented Aug. 28, 1928.1,682,572
UNITED STATES PATENT OFFICE.
Carl W. Keuffel of Weehawken, New Jersey, Assignor, to Keuffel and Esser Company, of Hoboken, New Jersey, a corporation of New Jersey.
Optical Instrument
Application filed October 15, 1925. Serial No. 62,502.
This invention relates: to optical instruments and particularly to spectrophotometers and the component parts thereof, Although there is an extensive field for the application5 of such instruments in the industries and many different types thereof have been devised, their use has practically been limited to research laboratories because most of the types heretofore produced could be 10used successfully only by those having an advanced scientific training. While such instruments as were adapted to the skill of men having only average training could be manufactured and sold only at a relatively 15high price.
In order that spectrophotometer be suitable for industrial purposes and for the average college laboratory it must meet the following requirements: 1st, The instrument 20must be susceptible of being manufactured and sold at a relatively low price; 2nd, the construction of the instrument must be based not only on correct scientific but also sound mechanical principles and design so that the 25results of observations will be within the required limits for precision and accuracy; 3rd, it must be sturdy and durable; 4th, the movable parts of the instrument must be so constructed that settings and readings can 30be made quickly and easily with a minimum of exertion on the part of, and fatigue to, the operator; 5th, the results of observations made with the instrument must be directly obtainable from suitable indicia without 35necessitating mathematical computations to obtain the required data, so that such data can be obtained and recorded by persons of average skill; and 6th, the construction of the instrument and particularly what may 40be termed the mechanical parts thereof, as distinguished from the optical elements such as lenses and prisms, must be such that the necessity for mathematical accuracy in the machining of the such parts will be obviated.
45It is the principal object of this invention to provide a spectrophotometer which will fully meet the above enumerated requirements.
A further object is to improve upon the 50construction of the spectrometer and photometer which not only form component parts of a spectrophotometer, but are also separately adapted for extensive use.
These and other objects will appear more fully to one skilled in the art to which the invention relates, from the following more detailed description and by reference to the55 accompanying drawings forming a part hereof, and wherein Fig. 1 is a diagrammatic plan view of a portion of a 60spectrophotometer embodying my invention showing the arrangement of the members; Fig. 2 is a diagrammatic side elevation of the optical system; Figs. 3 and 4 are diagrams of a portion of the spectrometer showing 65different positions of the optical wedge; Fig. 5 is a diagrammatic view of the photometric field; Figs. 6 and 7 are a side elevation and a plan respectively of my improved instrument; Figs. 8, 9 and 10 are70 views similar to Figs. 3 and 4 showing a different form of the invention and Fig. 11 is a detail side elevation of an adjusting device for use with the form of construction shown in Figs. 8 to 10 inclusive.75
The instrument will first be described by reference to the diagrammatic views of Figs. 1 to 5 inclusive in order that the underlying scientific principles of the construction may be more readily understood.80
As shown in Figs. 1 and 2 the instrument consists of a photometer designated generally by the reference character A, and a spectrometer designated by the reference character B. A portion of the radiant 85energy or light from any example, the lamp L reflected by the reflecting surfaces R1, R2, is directed by the prism P1, in two substantially parallel juxtaposed beams through the entrance slit S1 of 90 the collimator C and passes through the collimator objective L1. The parallel beams as they pass through the dispersion prism P2 are dispersed so that, in accordance with the well known properties of such prisms, 95the rays of different color present in the light beams will be deviated at different angles according to the wave length or frequency of each particular light ray; the resulting dispersed beam being brought to a100 focus at the ocular slit S2 of the telescope T by the telescope lens or objective L2.
A bi-prism P3 is interposed between the dispersing prism P2 and the telescope objective L2 to form a divided field of the type shown in Fig. 5; one half of the field as for