Dual beam spectrophotometer utilizing a spectral wedge and bifurcated fiber optic bundle

• US 3,885,879 A
• Filed: 06/25/1973
• Issued: 05/27/1975
• Est. Priority Date: 06/25/1973
• Status: Expired due to Term

• Current Assignee: Fisher Scientific Co. (Thermo Fisher Scientific Incorporated)
• Original Assignee: Nevitt M. Louder, Warren G. Gillingham
• Inventors: Louder, Nevitt M., Gillingham, Warren G.
• Primary Examiner(s): McGraw, Vincent P.
• Application Number:
  US05/372,931
• Time in Patent Office: 701 Days
• Field of Search: 356/189,186,100,96,97,88,93,94 250/227 350/166,96B
• US Class Current: 356/323
• CPC Class Codes: G01N 21/255 Details, e.g. use of specially adapted sources, lighting or optical systems

Abstract

A spectrophotometer including an adjustable spectral wedge, interposed between a light source and photosensitive means, for selecting wavelengths of light and improved fiber optics for transmitting the selected wavelengths to a sample to be analyzed. Single and dual beam spectrophotometers are disclosed.

Claims

1. A spectrophotometer comprising:

A. a source of light;

B. an adjustable wedge for selecting wavelengths of light from the source;

C. a reference means and a measuring means for sensing the selected wavelengths;

D. bifurcated fiber optics comprising a bundle of light conductive threads, one end of the bundle being of rectangular cross section and disposed adjacent the wedge, the opposite end of the bundle being divided into two branches, each branch containing approximately one half of the number of threads in the end of rectangular cross section, one branch being so positioned to transmit light through a sample to be analyzed to the measuring means and the other branch being so positioned to transmit light to the reference means; and

E. means for comparing the output of the sensing means.

2. A spectrophotometer as set forth in claim 1 wherein the spectral wedge is adjustable over a range of wavelengths from about 400 to about 700 nanometers.

3. A spectrophotometer as set forth in claim 1 in which the sensing means comprises a reference cell and a measuring cell.

4. A spectrophotometer as set forth in claim 1 and including means for displaying the comparison of the output of the cells.

5. A spectrophotometer as set forth in claim 4 in which the display means is a micro-ammeter.

6. A spectrophotometer as set forth in claim 1 wherein the end of the fiber optics adjacent the wedge has a substantially rectangular cross-section of a length approximately the height of the light of the wedge and a width of approximately 20 nanometers.

7. A spectrophotometer as set forth in claim 1 wherein the light source is a single filament lamp which presents an elongated light pattern on a face of the wedge.

8. A spectrophotometer as set forth in claim 1 and having means for holding a sample disposed between the end of one brancH of the fiber optics bundle and the measuring means.

9. A spectrophotometer as set forth in claim 8 in which the end of one branch of the fiber optics bundle is directly connected to the sample holding means.