Spectrophotometer

• US 4,687,329 A
• Filed: 12/12/1986
• Issued: 08/18/1987
• Est. Priority Date: 03/21/1985
• Status: Expired due to Term

• Current Assignee: Abbott Laboratories Incorporated
• Original Assignee: Abbott Laboratories Incorporated
• Inventors: Schultz, Steven G.
• Primary Examiner(s): Evans, F. L.
• Application Number:
  US06/941,247
• Time in Patent Office: 249 Days
• Field of Search: 356/308, 356/326, 356/328, 356/331, 356/332, 356/334, 356/414, 356/416, 356/417, 356/419, 250/226, 350/311, 350/317, 350/318, 357/30 H, 357/30 L, 358/43, 358/44
• US Class Current: 356/328
• CPC Class Codes: G01J 2003/2806 Array and filter array
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/0259 Monolithic
• CPC Class Codes: G01J 3/0262 Constructional arrangements for removing stray light
• CPC Class Codes: G01J 3/04 Slit arrangements slit adjustment
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01N 21/07 Centrifugal type cuvettes G01N21/09 takes precedence
• CPC Class Codes: G01N 2201/0642 Light traps; baffles
• CPC Class Codes: G01N 2201/0696 Pulsed
• CPC Class Codes: H01L 31/02164 for shielding light, e.g. light blocking layers, cold shields for infrared detectors

Abstract

An improved spectrophotometer, especially suitable for use in centrifugal analysis instrumentation, is disclosed. The spectrophotometer is improved by including therein a detector comprising a photodiode array assembly having a photodiode array, a spectral filter assembly situated substantially parallel thereto and in the path of incident light and means for attenuating stray light which would otherwise impinge on each of the photodiodes of the array.

Claims

1. In a spectrophotometer comprising:

(a) a flash lamp;

(b) a grating for receiving a beam of light delivered by the flash lamp which has passed through a sample for analysis; and

(c) a detector situated to receive the beam of light reflected by said grating;

the improvement wherein the detector comprises;

a photodiode array assembly including;

a plurality of individual photodiodes situated in a first plane wherein a substantial portion of said photodiodes are separated one from the other by an externally electrically grounded photodiode to reduce electrical crosstalk;

a plurality of individual adjacent spectral filters situated substantially parallel to said first plane and contacting said plurality of photodiodes wherein an optically opaque material surrounds each of said spectral filters, whereby components of light are allowed to pass through one of said spectral filters to one of said individual photodiodes but said components of light are blocked, after entering said one of said filters, from passing through any other one of said filters such that light passing through each of said individual adjacent spectral filters will impinge upon only one of said individual photodiodes; and

a means for attentuating stray light, said means being situated substantially parallel to said first plane and adjacent to said plurality of individual spectral filters such that said means is located above each of said individual photodiodes.

2. A method for producing a photodiode array assembly comprising the steps of:

(a) selecting a photodiode array having a plurality of individual photodiodes, each of said individual photodiodes having a preselected response to one or more wavelengths of light and separating a substantial portion of said photodiodes one from the other with an externally electrically grounded photodiode to reduce electrical crosstalk;

(b) selecting a spectral filter array having a plurality of individual adjacent spectral filters surrounded by a thin film of an optically opaque material such that each of said individual spectral filters transmits one or more preselected wavelengths of light; and

(c) mounting said spectral filter array in a plane parallel to said photodiode array such that each of said individual spectral filters is contacting one of said individual photodiodes;

whereby light passing through one of said individual spectral filters in said spectral filter array will impact on only one of said individual photodiodes in said photodiode array.

3. A photodiode array assembly comprising:

a photodiode array comprising a plurality of photodiodes situated in a first plane wherein a substantial portion of said photodiodes are separated by an externally electrically grounded photodiodes to reduce electrical crosstalk;

a plurality of spectral filters wherein each spectral filter is surrounded by a thin film, optically opaque material and where said spectral filters are situated substantially parallel to said first plane and contacting said photodiode array, such that light passing through one of said spectral filters impacts one of said photodiodes; and

means for attenuating stray light, said means being situated substantially parallel to said first plane and adjacent to said spectral filters, such that said means is located substantially over each of said photodiodes;

whereby light entering said stray light attenuating means is directed through said spectral filters to each of said photodiodes.