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US3712746A Expired / Lapsed US ⏱️ 0.0 years remaining

Device for optically determining microbial colony population on growth surface

Assignee: General Electric Co
•
Filing: 1971-07-29
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Granted: 1973-01-23
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Expires: 1991-07-29
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Abstract

Abstract A viewer-comparator device is described for optically determining the density of microbial colony growth in and on an inoculated nutrient layer. In the preferred construction the device comprises a base, a magnifying lens supported thereon, means connected to the base for supporting a nutrient layercoated surface, this surface being located in position for viewing thereof through the lens, means to enable direct visual comparison by an observer between the appearance of the nutrient layer-coated surface and reproductions of microbial growth at a plurality of representative intervals over a range of growth densities of clinical interest and lighting means depending from the base. The comparison enabling means is located adjacent the position to be occupied by the nutrient layer-coated surface for simultaneous viewing of both the comparison enabling means and the coated surface through the lens. The lighting means are so directed that light rays emanating therefrom cannot pass to the lens by reflection or by direct passage from lighting means to lens. With the lighting means so disposed and directed, the microbial colonies will scatter the light reaching them and appear bright in an essentially dark field (i.e. no bright background).

Inventors

  • 👤 J Bergeron

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-04 20:56
CPC Classifications
C; C12; C12M; C12M41/00; C12M41/30; C12M41/36; G; G02; G02B; G02B25/00; G02B25/02; Y; Y10; Y10S; Y10S435/00; Y10S435/808

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 221 words
A viewer/comparator device for optically determining microbial colony population density on a transparent surface having an inoculated nutrient layer thereon comprising in combination: a. an opaque base, b. at least one light source, c. means for mounting said light source on one side of said base, d. means connected to said base for positioning a transparent tubular member so that at least a portion of the length thereof is located on the opposite side of said base from said light source in which position light rays from said light source must pass directly to said portion to impinge thereon at an angle of incidence of greater than 45* with the central axis of said tubular member, e. means for enabling direct comparison by an observer between the appearance of said portion and reproductions of microbial growth at a plurality of representative intervals over a range of clinical interest, said comparison-enabling means being disposed adjacent the location available for the positioning of said portion and f. a magnifying lens supported on said opposite side of said base being spaced from said portion and disposed for simultaneous viewing of said portion and said comparisonenabling means, said light source being so directed that light rays passing therefrom to said opposite side of said base cannot pass directly to, or be reflected to, said lens.
Claim 2
Dependent Claim 221 words
A viewer/comparator device for optically determining microbial colony population density on a transparent surface having an inoculated nutrient layer thereon comprising in combination: a. an opaque base, b. at least one light source, c. means for mounting said light source on one side of said base, d. means connected to said base for positioning a transparent tubular member so that at least a portion of the length thereof is located on the opposite side of said base from said light source in which position light rays from said light source must pass directly to said portion to impinge thereon at an angle of incidence of greater than 45* with the central axis of said tubular member, e. means for enabling direct comparison by an observer between the appearance of said portion and reproductions of microbial growth at a plurality of representative intervals over a range of clinical interest, said comparison-enabling means being disposed adjacent the location available for the positioning of said portion and f. a magnifying lens supported on said opposite side of said base being spaced from said portion and disposed for simultaneous viewing of said portion and said comparisonenabling means, said light source being so directed that light rays passing therefrom to said opposite side of said base cannot pass directly to, or be reflected to, said lens.
Claim 3
Dependent Claim 41 words
The viewer/comparator device of claim 1 wherein a pair of light sources are employed, said light sources being directed so that the patterns of illumination of the two lamps cross each other at the portion of the tubular member being examined.
Claim 4
Dependent Claim 15 words
The viewer/comparator device of claim 1 wherein the attitude of the light source is adjustable.
Claim 5
Dependent Claim 18 words
The viewer/comparator device of claim 1 wherein the positioning means supports the tubular member at two spaced points.
Claim 6
Dependent Claim 14 words
The viewer/comparator device of claim 1 wherein the positioning means is a spring clamp.
Claim 7
Dependent Claim 13 words
The viewer/comparator device of claim 1 wherein the comparison-enabling means is a photograph.

References Cited (Backward Citations)

US2157438A Cited
US2427790A Cited
US2495912A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1976-01-23 1976-07-24 1977-01-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1980-01-23 1980-07-24 1981-01-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1984-01-23 1984-07-24 1985-01-23 $7700.00 Window Closed / Lapsed

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