WO1995017663A1 - Spectrophotometer and a printed circuit board for use therein - Google Patents

Spectrophotometer and a printed circuit board for use therein Download PDF

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Publication number
WO1995017663A1
WO1995017663A1 PCT/GB1994/002775 GB9402775W WO9517663A1 WO 1995017663 A1 WO1995017663 A1 WO 1995017663A1 GB 9402775 W GB9402775 W GB 9402775W WO 9517663 A1 WO9517663 A1 WO 9517663A1
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WO
WIPO (PCT)
Prior art keywords
light
circuit board
spectrophotometer
printed circuit
sensor
Prior art date
Application number
PCT/GB1994/002775
Other languages
French (fr)
Inventor
Nigel Bryan Chitty
Original Assignee
Nigel Bryan Chitty
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nigel Bryan Chitty filed Critical Nigel Bryan Chitty
Publication of WO1995017663A1 publication Critical patent/WO1995017663A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/251—Colorimeters; Construction thereof
    • G01N21/253—Colorimeters; Construction thereof for batch operation, i.e. multisample apparatus

Definitions

  • the present invention relates to an improved spectrophotometer having a number of randomly accessible wells, and a printed circuit board for use therein.
  • Spectrophotometers are well known in the art and are used for monitoring the colour or turbidity of a sample by shining a source of light through the sample for subsequent detection.
  • Previously such devices have been provided which allow only one sample at a time to be inserted in and read by the device.
  • spectrophotometers have been developed which allow each well of a multi-well microtiter plate to be read sequentially.
  • the known devices are useful, there are certain drawbacks.
  • the manual devices are laborious to use.
  • the microplate readers cannot be readily interrupted once the reading is commenced and may only operate at a limited speed in view of the sequential reading arrangement.
  • a number or all the wells have a common reference which will not therefore take into account differences for example, in the aliquot size or initial colour differences between each well.
  • a further problem which arises in relation to the known spectrophotometers relates to the activation of the device to take a reading.
  • this has been done by including a mechanical switch, placed at the bottom of the channel into which the test tube is placed which is depressed once a sample has been inserted, thus activating the spectrophotometer to take a reading.
  • the provision of such a mechanical switch increases the cost involved in the manufacture of the instrument and is also liable to mechanical breakdowns.
  • a printed circuit board adapted to activate a spectrophotometer to take a reading, having a first circuit capable of generating an electrical current signal and a second circuit responsive to a light sensor, the light sensor measuring a characteristic of the light received and being activated to take said measurement by said electrical current signal.
  • a spectrophotometer for measuring the light characteristics of a sample comprising a plurality of channels into which samples may be placed, each channel having a fibre optic light source and the printed circuit board.
  • the first circuit is responsive to a light sensor, generating an electrical current signal in response to changes in light received.
  • the light sensor of the first circuit is a light to current converter
  • the light sensor of the second circuit is a light to frequency converter.
  • the first circuit comprises a surface mounted key switch such as a beryllium copper spring which completes the circuit when a sample is placed in the channel depressing the switch.
  • the beryllium copper spring is attached to the end of a plunger, preferably made of rubber which is pushed inwards as a sample is placed in the channel.
  • each well may be randomly accessed and incorporates its own light source and light to frequency converter for detection of transmission charges in the sample in either colour or light strength.
  • Wells may be incubated to a desired temperature.
  • Each well may incorporate a light to current converter to act as a non- mechanical switch, detecting changes in the sample effectively switching on the system for measurement of light strength or colour passing through the sample.
  • software is provided so that readings may be taken at selected intervals from a particular well over a set time course. In this way the kinetics of a reaction may be monitored.
  • Figure 1 is a plan view of the spectrophotometer
  • Figure 2 is a sectional view through one of the wells of ⁇ the spectrophotometer
  • Figure 3 is a plan view of the printed circuit board shown in Figure 2;
  • Figure 4 is a plan view of an alternative printed circuit board
  • a spectrophotometer generally indicated 1 in Figure 1 has a plurality of wells 2.
  • the spectrophotometer 1 is provided with sixty-four wells, arranged in a circular aluminium block 25.
  • a well 2 is shown in more detail comprising a holder 3 within which a test-tube 4 holding a sample may be inserted.
  • Each well 2 is provided with its own light source 5 through a lensed fibre optic bundle.
  • a fibre optic harness 6 receives light from a single source, in this case a halogen bulb 7.
  • the fibre optic bundle 8 leading from the harness 6 is arranged so that each well 2 is provided with its own fibre optic light source 5.
  • Light from the light source 5 passes through the well 2 through slits 9, 10 in holder 3 and sample 4 when present to a light sensor, in this case a light to frequency converter 11 shown in Figure 3.
  • the light to frequency converter detects the colour or light strength of light passing through the sample 4 to give an indication of colour and turbidity changes within the sample.
  • the light to frequency converter 11 is connected to a main printed circuit board 12 of the spectrophotometer and the data may be fed through appropriate software for easy analysis.
  • Holder 3 is provided with a second set of apertures 13 , 14 through which light from fibre optic light source 5 may pass.
  • This light having passed through sample 4 is detected by a second light sensor, in this case a light to current converter 15.
  • This light to current converter 15 detects a rise or fall in the light value from fibre optic light source 5 which leads to the generation of an electric current value to act as a non-mechanical switch to activate the system to take a reading from the light to frequency converter. In this way, each time a new sample is placed within the holder the system is activated to take readings.
  • the light to current converter 15 is located in close proximity to light to frequency converter 11 on the same electrical printed circuit board 19, to form the reader board generally indicated 16 in the figures.
  • Each well 2 is provided with a reader board 16.
  • a six pin male to female connector 17, 18 is used to connect printed circuit board 19 to the main printed circuit board 12 for power and data transmission.
  • Processing means 20 may be provided on the device and linked to appropriate computer hard or software for data analysis and control of the spectrophotometer.
  • the light converters are housed within a soft plastics housing 21 which in practise lies against wall 22 of the holder 3 of the well 2. In this way light spillage is kept to a minimum.
  • a printed circuit board has a light to frequency converter which is connected to a main printed circuit board 12 of the spectrophotometer in the same manner as the printed circuit board of Figure 3.
  • a key switch 28 is mounted on the printed circuit board 26.
  • the key switch is a beryllium copper spring which is attached to the end of the rubber plunger which passes through an aperture in the channel wall (not shown) .
  • the rubber plunger is depressed, pushing the beryllium copper spring onto the first circuit, generating an electrical current to act as a switch to activate the system to take reading from the light to frequency converter.
  • the first circuit is completed as the test tube 4 is placed within the holder 3, activating the light to frequency converter.
  • Each well is provided with a fibre optic light source and one or both light sensors as described above. In the embodiment shown, sixty four wells are provided, conveniently arranged in a circle which helps to minimize light spillage from one well to the next. Each well may also be provided with a light emitting diode 23 to indicate the functioning state of the well. The wells may also be provided with incubation means with appropriate control to maintain a desired temperature in all wells. The incubation means is provided as a circular heater band 24 lying inside the well block 25.
  • Biasing means may be provided in the holder 3, for example, in the form of a rubber plunger (not shown) which biases the test tube 4 against the channel wall, thus holding the test tube in place while the assay is carried out.
  • the switch may additionally function as the biasing means for the test tube.
  • the light wavelengths used may be changed as desired depending on the sample being read.
  • Each well is referenced individually to gain a zero value. Such zero value is recorded and will provide the reference for any further readings.
  • spectrophotometer- may be used depending on whether it is desirable to measure the kinetics of a particular reaction or whether it is merely an end point reading which is desired.
  • a sample is inserted in the well and the mean from the first zero reading taken from the well is used as the reference.
  • the insertion of the sample will activate the reader through the light to current converter.
  • the sample may be incubated at a particular temperature if desired. All wells may be programmed using appropriate software to take readings at selected time intervals over a particular time period. In this way the kinetics of a particular reaction may readily be studied.
  • each well may be first referenced.
  • the samples to be read are then inserted into the wells. Each time a new sample is placed into a well, the light to current converter generates an electrical value activating the device so that a transmission reading is then taken by the light to frequency converter.

Abstract

A printed circuit board has a first circuit capable of generating an electrical current signal and a second circuit responsive to a light sensor. The light sensor in the second circuit measures a characteristic of the light received and is activated to take a measurement by the electrical current signal. The printed circuit board may be used in a spectrophotometer for measuring the light characteristics of a sample placed within a channel of the spectrophotometer.

Description

Spectrophotometer And A Printed Circuit Board For Use Therein
The present invention relates to an improved spectrophotometer having a number of randomly accessible wells, and a printed circuit board for use therein.
Spectrophotometers are well known in the art and are used for monitoring the colour or turbidity of a sample by shining a source of light through the sample for subsequent detection. Previously such devices have been provided which allow only one sample at a time to be inserted in and read by the device. More recently, spectrophotometers have been developed which allow each well of a multi-well microtiter plate to be read sequentially.
These devices are commonly used in the laboratory for measuring colour or light strength changes in ELISA applications, immune assays, studies in cycotoxicity, microbiology, enzymology, clotting factors and food science.
While the known devices are useful, there are certain drawbacks. In particular, the manual devices are laborious to use. The microplate readers cannot be readily interrupted once the reading is commenced and may only operate at a limited speed in view of the sequential reading arrangement. A number or all the wells have a common reference which will not therefore take into account differences for example, in the aliquot size or initial colour differences between each well. It may also be desirable to incubate the samples to be assayed. However such incubation must take place at a fixed temperature for all samples .
It is often desirable to follow the kinetic aspects of reactions, particularly when enzymes are involved. The spectrophotometers currently available do not provide an easy way of following the kinetics of a reaction.
A further problem which arises in relation to the known spectrophotometers relates to the activation of the device to take a reading. Previously, this has been done by including a mechanical switch, placed at the bottom of the channel into which the test tube is placed which is depressed once a sample has been inserted, thus activating the spectrophotometer to take a reading. The provision of such a mechanical switch increases the cost involved in the manufacture of the instrument and is also liable to mechanical breakdowns.
In a first aspect of the present invention there is provided a printed circuit board adapted to activate a spectrophotometer to take a reading, having a first circuit capable of generating an electrical current signal and a second circuit responsive to a light sensor, the light sensor measuring a characteristic of the light received and being activated to take said measurement by said electrical current signal.
In a second aspect of the present invention we provide a spectrophotometer for measuring the light characteristics of a sample comprising a plurality of channels into which samples may be placed, each channel having a fibre optic light source and the printed circuit board.
In preferred embodiments, the first circuit is responsive to a light sensor, generating an electrical current signal in response to changes in light received. Preferably, the light sensor of the first circuit is a light to current converter, and the light sensor of the second circuit is a light to frequency converter. Alternatively, the first circuit comprises a surface mounted key switch such as a beryllium copper spring which completes the circuit when a sample is placed in the channel depressing the switch. The beryllium copper spring is attached to the end of a plunger, preferably made of rubber which is pushed inwards as a sample is placed in the channel.
Preferably, each well may be randomly accessed and incorporates its own light source and light to frequency converter for detection of transmission charges in the sample in either colour or light strength. Wells may be incubated to a desired temperature. Each well may incorporate a light to current converter to act as a non- mechanical switch, detecting changes in the sample effectively switching on the system for measurement of light strength or colour passing through the sample. Additionally software is provided so that readings may be taken at selected intervals from a particular well over a set time course. In this way the kinetics of a reaction may be monitored.
The invention is hereafter described by way of example only with reference to the accompanying drawings in which:
Figure 1 is a plan view of the spectrophotometer
Figure 2 is a sectional view through one of the wells of^ the spectrophotometer;
Figure 3 is a plan view of the printed circuit board shown in Figure 2;
Figure 4 is a plan view of an alternative printed circuit board;
A spectrophotometer generally indicated 1 in Figure 1 has a plurality of wells 2. In the embodiment shown the spectrophotometer 1 is provided with sixty-four wells, arranged in a circular aluminium block 25. Referring to Figure 2, a well 2 is shown in more detail comprising a holder 3 within which a test-tube 4 holding a sample may be inserted. Each well 2 is provided with its own light source 5 through a lensed fibre optic bundle. A fibre optic harness 6 receives light from a single source, in this case a halogen bulb 7. The fibre optic bundle 8 leading from the harness 6 is arranged so that each well 2 is provided with its own fibre optic light source 5. Light from the light source 5 passes through the well 2 through slits 9, 10 in holder 3 and sample 4 when present to a light sensor, in this case a light to frequency converter 11 shown in Figure 3. The light to frequency converter detects the colour or light strength of light passing through the sample 4 to give an indication of colour and turbidity changes within the sample.
The light to frequency converter 11 is connected to a main printed circuit board 12 of the spectrophotometer and the data may be fed through appropriate software for easy analysis.
Holder 3 is provided with a second set of apertures 13 , 14 through which light from fibre optic light source 5 may pass. This light having passed through sample 4 is detected by a second light sensor, in this case a light to current converter 15. This light to current converter 15 detects a rise or fall in the light value from fibre optic light source 5 which leads to the generation of an electric current value to act as a non-mechanical switch to activate the system to take a reading from the light to frequency converter. In this way, each time a new sample is placed within the holder the system is activated to take readings.
The light to current converter 15 is located in close proximity to light to frequency converter 11 on the same electrical printed circuit board 19, to form the reader board generally indicated 16 in the figures. Each well 2 is provided with a reader board 16. A six pin male to female connector 17, 18 is used to connect printed circuit board 19 to the main printed circuit board 12 for power and data transmission. Processing means 20 may be provided on the device and linked to appropriate computer hard or software for data analysis and control of the spectrophotometer.
The light converters are housed within a soft plastics housing 21 which in practise lies against wall 22 of the holder 3 of the well 2. In this way light spillage is kept to a minimum.
In the alternative arrangement shown in Figure 4 a printed circuit board has a light to frequency converter which is connected to a main printed circuit board 12 of the spectrophotometer in the same manner as the printed circuit board of Figure 3. A key switch 28 is mounted on the printed circuit board 26. The key switch is a beryllium copper spring which is attached to the end of the rubber plunger which passes through an aperture in the channel wall (not shown) . As the test tube 4 holding a sample is inserted within the holder 3, the rubber plunger is depressed, pushing the beryllium copper spring onto the first circuit, generating an electrical current to act as a switch to activate the system to take reading from the light to frequency converter. Effectively, the first circuit is completed as the test tube 4 is placed within the holder 3, activating the light to frequency converter.
Each well is provided with a fibre optic light source and one or both light sensors as described above. In the embodiment shown, sixty four wells are provided, conveniently arranged in a circle which helps to minimize light spillage from one well to the next. Each well may also be provided with a light emitting diode 23 to indicate the functioning state of the well. The wells may also be provided with incubation means with appropriate control to maintain a desired temperature in all wells. The incubation means is provided as a circular heater band 24 lying inside the well block 25.
Biasing means may be provided in the holder 3, for example, in the form of a rubber plunger (not shown) which biases the test tube 4 against the channel wall, thus holding the test tube in place while the assay is carried out. Where a key switch is used to activate the light to frequency converter 11, the switch may additionally function as the biasing means for the test tube.
The light wavelengths used may be changed as desired depending on the sample being read.
Each well is referenced individually to gain a zero value. Such zero value is recorded and will provide the reference for any further readings.
There are effectively two ways in which the spectrophotometer- may be used depending on whether it is desirable to measure the kinetics of a particular reaction or whether it is merely an end point reading which is desired.
To carry out a kinetic assay, a sample is inserted in the well and the mean from the first zero reading taken from the well is used as the reference. The insertion of the sample will activate the reader through the light to current converter. The sample may be incubated at a particular temperature if desired. All wells may be programmed using appropriate software to take readings at selected time intervals over a particular time period. In this way the kinetics of a particular reaction may readily be studied. In the alternative, each well may be first referenced. The samples to be read are then inserted into the wells. Each time a new sample is placed into a well, the light to current converter generates an electrical value activating the device so that a transmission reading is then taken by the light to frequency converter.

Claims

1 A printed circuit board adapted to activate a spectrophotometer to take a reading, having a first circuit capable of generating an electrical current signal and a second circuit responsive to a light sensor, the light sensor measuring a characteristic of the light received and being activated to take said measurement by said electrical current signal.
2 A printed circuit board according to Claim 1 wherein said first circuit is responsive to a light sensor in close proximity to said light sensor of the second circuit, the light sensor in the first circuit generating said electrical current signal in response to changes in light received.
3 An electrical printed circuit board according to Claim 2 wherein said first sensor is a light to current converter and said second sensor is a light to frequency converter.
4 A printed circuit board according to Claim 1 wherein said printed circuit board has a surface mounted key switch, said first circuit generating an electrical current signal in response to said key switch.
5 A printed circuit board according to Claim 4 wherein said switch comprises a beryllium copper spring.
6 A spectrophotometer for measuring the light characteristics of a sample comprising a plurality of channels into which samples may be placed, each channel having a fibre optic light source and a printed circuit board according to any preceding claim, wherein said second light sensor measures a characteristic of the light received from said light source having passed through said channel .
7 A spectrophotometer according to Claim 6 wherein the characteristic of light measured is light colour or light strength.
8 A spectrophotometer according to any of Claims 6 or Claim 7 wherein each light sensor has a housing which shields the light sensors from light other than that received from said fibre optic light source.
9 A spectrophotometer according to any of Claims 6, 7 or 8 wherein each fibre optic light source has a housing to reduce transmission of light other than through said sample to said light sensors.
10 A spectrophotometer according to any of Claims 6 to 9 wherein the channels are arranged to minimise the effects of light scattering on neighbouring channels, preferably said channels being arranged in a circle.
11 A spectrophotometer according to any of Claims 6 to 10 wherein all channels are provided with controlled heating means .
12 A spectrophotometer according to any of Claims 6 to 11 wherein each of said channel is of circular cross section to receive circular cross section test tubes contain said samples .
13 A spectrophotometer according to Claim 4 or 5 and any of Claims 6 to 12 wherein said switch comprises a spring which is extended to bias a sample within said channel again
PCT/GB1994/002775 1993-12-21 1994-12-21 Spectrophotometer and a printed circuit board for use therein WO1995017663A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9326078.4 1993-12-21
GB939326078A GB9326078D0 (en) 1993-12-21 1993-12-21 Spectrophotometer

Publications (1)

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WO1995017663A1 true WO1995017663A1 (en) 1995-06-29

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6246471B1 (en) * 1998-06-08 2001-06-12 Lj Laboratories, Llc Apparatus and method for measuring optical characteristics of an object
EP1234169A1 (en) * 1999-11-26 2002-08-28 Associates Of Cape Cod, Inc. Pyros kinetix reader for conducting assays
BE1018827A3 (en) * 2009-07-16 2011-09-06 Praet Peter Van LED DENSITOMETER FOR MICRO TITER PLATE.
US8998613B2 (en) 1997-01-02 2015-04-07 511 Innovations Inc. Apparatus and method for measuring optical characteristics using a camera and a calibration chart imaged with the camera

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3882318A (en) * 1974-01-21 1975-05-06 Hycel Inc Detector means for an automatic chemical testing apparatus
US4125327A (en) * 1975-11-17 1978-11-14 Gradient Pty. Limited Method and apparatus for simultaneously recording reaction times
EP0303524A2 (en) * 1987-08-11 1989-02-15 Associates Of Cape Cod, Inc. Instrument for independently and kinetically measuring light transmission through a plurality of samples
EP0516274A2 (en) * 1991-05-27 1992-12-02 Kowa Co. Ltd. Multichannel optical measuring system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3882318A (en) * 1974-01-21 1975-05-06 Hycel Inc Detector means for an automatic chemical testing apparatus
US4125327A (en) * 1975-11-17 1978-11-14 Gradient Pty. Limited Method and apparatus for simultaneously recording reaction times
EP0303524A2 (en) * 1987-08-11 1989-02-15 Associates Of Cape Cod, Inc. Instrument for independently and kinetically measuring light transmission through a plurality of samples
EP0516274A2 (en) * 1991-05-27 1992-12-02 Kowa Co. Ltd. Multichannel optical measuring system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8998613B2 (en) 1997-01-02 2015-04-07 511 Innovations Inc. Apparatus and method for measuring optical characteristics using a camera and a calibration chart imaged with the camera
US6246471B1 (en) * 1998-06-08 2001-06-12 Lj Laboratories, Llc Apparatus and method for measuring optical characteristics of an object
EP1234169A1 (en) * 1999-11-26 2002-08-28 Associates Of Cape Cod, Inc. Pyros kinetix reader for conducting assays
EP1234169A4 (en) * 1999-11-26 2005-06-15 Ass Cape Cod Inc Pyros kinetix reader for conducting assays
BE1018827A3 (en) * 2009-07-16 2011-09-06 Praet Peter Van LED DENSITOMETER FOR MICRO TITER PLATE.

Also Published As

Publication number Publication date
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