COLORIMETER FOR MEASURING CONCENTRATION AND INDICATING THE CONCENTRATION AS A DIGITAL QUANTITY

• US 3,743,429 A
• Filed: 05/17/1971
• Issued: 07/03/1973
• Est. Priority Date: 05/18/1970
• Status: Expired due to Term

• Current Assignee: Shoji Kawai
• Original Assignee: Shoji Kawai
• Inventors: Kawai, Shoji
• Primary Examiner(s): Wibert, Ronald L.
• Assistant Examiner(s): Evans, F. L.
• Application Number:
  US05/143,901
• Time in Patent Office: 778 Days
• Field of Search: 356/96,97,176,177,180-186,188-190,195,201,204-206 250/218
• US Class Current: 356/409
• CPC Class Codes: G01N 21/253 for batch operation, i.e. multisample apparatus analytical automats G01N35/00
• CPC Class Codes: G01N 21/27 using photo-electric detection G01N21/31 takes precedence; circuits for computing concentration logarithmic circuits G06G7/24; photometric circuits in general G01J
• CPC Class Codes: H03M 1/00 Analogue/digital conversion; Digital/analogue conversion conversion of analogue values to or from differential modulation H03M3/00
• CPC Class Codes: H03M 1/1071 Measuring or testing

Abstract

A colorimeter for testing specimens such as blood samples in order to measure the concentration of a material in the specimen and indicate the concentration as a digital quantity. The specimen which is to be tested is supported at a test position, and a signal-producing structure coacts with the specimen at the test position for producing therefrom a signal indicative of the concentration of a given material in the specimen. An analogdigital transducer receives the signal and converts it into a digital quantity, the magnitude of which is indicative of the concentration. An indicator is connected to the transducer for indicating the digital quantity determined by the transducer.

Claims

1. In a colorimeter for determining the concentration of a given material in a given specimen, support means for supporting a specimen in a test position, signal-producing means located at the region of said support means for coacting with a specimen at said test position to produce therefrom a signal which is indicative of the concentration of a given material in the specimen at said test position, analog-digital transducer means operatively connected with said signal-producing means for receiving a signal therefrom and for converting said signal into a digital quantity the magnitude of which is indicative of said concentration, and indicating means operatively connected with said transducer means for indicating said digital quantity, said analog-digital transducer means including a comparator connected electrically to said signal-producing means for receiving a signal therefrom and an integrator connected electrically to said comparator for transmitting thereto a signal to be compared with the signal produced by said signal-producing means, said transducer means converting said signal from said signalproducing means into said digital quantity when the signal from said integrator equals the signal from said signal-producing means.

2. The combination of claim 1 and wherein a reset switch means is operatively connected with said transducer means for clearing the last-determined digital quantity therefrom and for resetting said transducer means to determine the next digital quantity when a new specimen has been placed at said test position.

3. The combination of claim 1 and wherein an incubator means is located adjacent said support means for bringing a specimen to a predetermined temperature before the specimen is situated at said test position.

4. The combination of claim 1 and wherein said transducer means also includes a bistable multivibrator connected to said comparator to receive the output thereof and a reset switch means electrically connected with said bistable multivibrator for clearing the last-determined digital quantity from said transducer means and for resetting the latter to determine the next digital quantity when a new specimen has been placed at said test position.

5. The combination of claim 4 and wherein said transducer means further includes an AND gate circuit and a decimal counter both connected electrically with said bistable multivibrator, said decimal counter also being electrically connected with said integrator for resetting the latter in response to operation of said reset switch means, and a non-stable multivibrator electrically connected with said AND gate circuit for transmitting through the latter to said decimal counter a signal having pulses of predetermined frequency, the number of the latter pulses being counted by said decimal counter until the signal from said integrator equals the signal from said signal-producing means, the latter signals being compared by said comparator.

6. The combination of claim 5 and wherein said indicating means includes a fluorescent counting indicator tube electrically connected to said decimal counter to be operated thereby and indicating the concentration as an absolute value.

7. The combination of claim 1 and wherein said signal-producing means includes a light source for directing light through a specimen at said test position, photosensitive means for receiving the light and converting the latter into a predetermined signal, a pre-amplifier for receiving the latter signal from said photosensitive means and amplifying the signal, and a logarithmic transducer electrically connected to said pre-amplifier for receiving an exponential output electrical signal therefrom and for converting the latter to a linear output signal which is transmitted to said analog-digital Transducer means.

8. The combination of claim 7 and wherein a heat filter is located between said light source and test position and a color filter is located between said test position and photosensitive means, so that the heat filter acts on the light before it reaches the specimen while the color filter coacts with light which has passed through the specimen to compensate for properties of the reagent thereof.

9. In a colorimeter for determining the concentration of a given material in a given specimen, support means for supporting a specimen in a test position, signal-producing means located at the region of said support means for co-acting with a specimen at said test position to produce therefrom a signal which is indicative of the concentration of a given material in the specimen at said test position, analog-digital transducer means operatively connected with said signal-producing means for receiving a signal therefrom and for converting said signal into a digital quantity the magnitude of which is indicative of said concentration, and indicating means operatively connected with said transducer means for indicating said digital quantity, a compensating means operatively connected with said signal-producing means for influencing the latter to provide a signal which is compensated for the properties of a reagent of the specimen, said compensating means including a meter operatively connected to said signal-producing means for receiving the signal produced thereby and transmitted to said transducer means, said meter indicating the magnitude of said signal as produced by the reagent alone, and said compensating means including an adjusting means operatively connected to said signal-producing means for adjusting the latter to zero the meter so as to compensate for the properties of the reagent.

10. The combination of claim 9 and wherein said signal-producing means includes a light source for directing light through a specimen at said test position, a voltage stabilizer operatively connected to said light source for stabilizing the voltage transmitted thereto, and said adjusting means including a variable resistor operatively connected to said voltage stabilizer for adjusting the latter to zero said meter to compensate for the properties of the reagent.

11. In a colorimeter for determining the concentration of a given material in a given specimen, support means for supporting a specimen in a test position, signal-producing means located at the region of said support means for coacting with a specimen at said test position to produce therefrom a signal which is indicative of the concentration of a given material in the specimen at said test position, analog-digital transducer means operatively connected with said signal-producing means for receiving a signal therefrom and for converting said signal into a digital quantity the magnitude of which is indicative of said concentration, and indicating means operatively connected with said transducer means for indicating said digital quantity, a manually operable selecting means operatively connected with said transducer means for selecting one of a plurality of different tests to be carried out, and display means operatively connected with said selecting means for displaying the selected test, said transducer means including an integrator and a comparator connected electrically to said integrator for receiving a signal therefrom, said comparator also being connected electrically to said signal-producing means for receiving a signal from the latter to compare the latter signal with the signal received from said integrator, and said selecting means including a plurality of resistors respectively corresponding to absorption constants of different reagents, said selecting means placing in the voltage input to said integrator that one of said resistors which corresponds to the absorption constant of the reagent in the specimen which is to be tested.