GB2590059A

GB2590059A - A medical device for measuring a concentration of an entity in a digit

Info

Publication number: GB2590059A
Application number: GB1915099.4A
Authority: GB
Inventors: Kale Izzet; Turgul Volkan
Original assignee: University of Westminster
Current assignee: University of Westminster
Priority date: 2019-10-18
Filing date: 2019-10-18
Publication date: 2021-06-23
Also published as: WO2021074631A1; GB201915099D0

Abstract

A device 700 to measure the concentration of a blood parameter (e.g. glucose) includes a housing into which the digit of a user is received, a non-invasive blood parameter concentration sensor (e.g. optical 727, electromagnetic 725) and a pressure sensor 725 to measure pressure applied by the digit onto the concentration sensor. The housing has a hinge 722, base 720 and lid 721, and the device adjusts the pressure applied to the sensor by the finger dependent on the measured pressure. Blood glucose readings may be taken when the applied finger pressure is within a predetermined range, thus increasing measurement reliability. Alternatively or additionally to using finger pressure measurement, the device may control the volume of blood in the finger using a tourniquet 710, and determine digit orientation for example using a fingerprint sensor 726 (see figs 8-10). Measurements may be suspended until the finger is positioned correctly or an adjustment made to a measurement taken at an incorrect position.

Description

Intellectual Property Office Application No G131915099.4 RTM Date:31 March 2021 The following terms are registered trade marks and should be read as such wherever they occur in this document: Bluetooth Zigbee Intellectual Property Office is an operating name of the Patent Office www.gov.uk/ipo A Medical Device for Measuring a Concentration of an Entity in a Digit

Technical Field

The present invention relates to a medical device for measuring a concentration of an entity, such as blood glucose levels, in a digit.

Background

It is known to provide medical devices for monitoring blood glucose levels. These medical devices can be important in managing diabetes and other medical conditions. The medical devices may be configured to pierce the skin to draw blood and then to measure the blood glucose levels in the blood drawn. There are also non-invasive medical devices which attempt to measure blood glucose levels without drawing blood. These noninvasive medical devices use electromagnetic or optical measurement methods to determine blood glucose levels. However, non-invasive devices are less reliable than those that draw blood, and although they may be preferred by a user in that they are non-invasive, they do not give consistently accurate blood glucose level readings.

Summary

In one example, a medical device for measuring a concentration of an entity in a digit is provided. The device comprises a housing for receiving a digit of a user, the housing comprising a base and a lid, and a connector connecting the lid to the base. The device further comprises a processing circuitry and a sensor unit, the processing circuitry is configured to operate the sensor unit for measuring a concentration of an entity in the digit, a pressure sensor configured to determine the pressure applied by the digit onto the sensor unit, and the processing circuitry being further configured to adjust the lid relative to the base dependent on the determined pressure.

In one example, the device further comprises a tourniquet to be positioned at least partially around a tip of the digit to control the blood flow to and from the digit.

In one example, the tourniquet is configured to be positioned at least partially around a finger where the distal phalanx or middle phalanx is located.

In one example, the device further comprises a blood volume sensor configured to measure the volume of blood in the digit.

In one example, the processing circuitry is configured to receive a reading from the blood volume sensor and adjust the tourniquet based on the reading so as to increase or restrict blood flow in the digit.

In one example, the processing circuitry is configured to receive a reading from the pressure sensor and when the reading falls within a predetermined range, the processing circuitry is configured to send a signal to the sensor unit to measure a concentration of an entity in the digit.

In one example, the device further comprises a fingerprint sensor for determining an orientation of the digit relative to the sensor unit.

In one example, the processing circuitry is configured to receive information of the orientation of a digit from the fingerprint sensor and when the orientation of a digit falls within a predetermined range of orientations, the processing circuitry is further configured to send a signal to the sensor unit to measure a concentration of an entity in the digit.

In another example, a medical device for measuring a concentration of an entity in a digit is provided. The device comprises a housing for receiving a digit of a user, a processing circuitry and a sensor unit, the processing circuitry is configured to operate the sensor unit for measuring a concentration of an entity in the digit, a tourniquet configured to be positioned at least partially around a tip of the digit to control blood flow to and from the digit, a blood volume sensor configured to take a reading indicative of the volume of blood in the digit, and the processing circuitry being further configured to determine the volume of blood in the digit based on the reading and to adjust the tourniquet dependent on the determined volume of blood in the digit.

In one example, the device comprises a fingerprint sensor for determining the orientation of the digit on the sensor unit.

In yet another example, a medical device for measuring a concentration of an entity in a digit is provided. The device comprises a housing for receiving a digit of a user, a processing circuitry and a sensor unit, the processing circuitry is configured to operate the sensor unit for measuring a concentration of an entity in the digit, a fingerprint sensor for determining the orientation of the digit on the sensor unit, and the processing circuitry further being configured to determine if the orientation of the digit falls within a predetermined range of orientations.

In one example, the processing circuitry is further configured to send a signal to the sensor unit to measure a concentration of an entity in the digit if the orientation of the digit falls within the predetermined range of orientations.

In one example, the housing comprises a base and a lid, and a connector connecting the lid to the base, and a pressure sensor configured to determine the pressure applied by the digit onto the sensor unit, and the processing circuitry being further configured to adjust the lid relative to the base dependent on the determined pressure.

In any of the examples above, the connector may be motorised and operated by the processing circuitry.

In any of the examples above, the sensor unit may comprise a radio frequency sensor and/or an optical sensor.

In another example, a method performed by a medical device for measuring a concentration of an entity in a digit is provided. The medical device comprises a lid and a base, the method comprises determining a pressure applied by a digit onto a sensor unit of the medical device and adjusting the pressure by moving the lid relative to the base, the method further comprises the sensor unit measuring a concentration of an entity in a digit.

In yet another example, a method performed by a medical device for measuring a concentration of an entity in a digit is provided. The method comprises positioning a tourniquet of the medical device at least partially around a tip of a digit of a user to control blood flow to and from the digit, the method further comprises a sensor unit of the medical device measuring a concentration of an entity in the digit.

In yet a further example, a method performed by a medical device for measuring a concentration of an entity in a digit is provided. The method comprises determining the orientation of a digit relative to said medical device, and if the orientation of the digit falls within a predetermined range of orientations relative to the medical device, the method further comprises a sensor unit of the medical device measuring a concentration of an entity in the digit.

Brief description of the drawings

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the following drawings in which: Figure 1 is a box diagram of an example of a medical device; Figure 2 is a box diagram of another example of a medical device; Figure 3 is a box diagram of yet another example of a medical device; Figure 4 is yet another box diagram of an example of a medical device; Figure 5 is a box diagram of a further example of a medical device; Figure 6 is a box diagram of another example of a medical device; Figure 7 is a schematic representation of an implementation of a medical device; Figure 8 is a flow chart of an example of a method; Figure 9 is a flow chart of another example of a method; Figure 10 is a flow chart of yet another example of a method; and Figure 11 is a box diagram of an example of a medical device. Detailed Description Non-invasive medical devices for measuring blood glucose levels can be configured to receive a finger of a patient or user and then to take a reading of the blood glucose levels present in the finger. It has been determined that several factors affect the accuracy of

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such a non-invasive medical device. One of these factors is the pressure applied by the finger onto a sensor of the medical device configured to measure the blood glucose level. If the pressure is too much or too little, the blood glucose readings can be inaccurate. Another factor affecting the accuracy of a non-invasive medical device configured to measure blood glucose levels is the volume of blood present in the finger when the blood glucose level is being measured. If the blood volume differs between each reading then the readings of the blood glucose levels will not be comparable, and the accuracy is reduced. Yet another factor affecting the accuracy is the orientation of the finger relative to the medical device when the blood glucose level is being measured. The orientation of the finger impacts the blood glucose level readings such that if the finger is slightly misaligned, the blood glucose level readings will be inaccurate.

Different examples will be described below that addresses the above mentioned factors. However, before the figures are described, it is to be clarified that the examples of the present invention are not limited to measuring or determining blood glucose levels. In fact, the examples described herein are configured to measure or determine a concentration of an entity in a digit. This entity can be anything that is measurable using electromagnetic and/or optical methods. For example, an "entity" can be a blood glucose, skin moisture levels, body hydration levels, blood viscosity and/or blood salinity levels. Furthermore, it should be understood that a "sensor unit" referred to herein comprises an electromagnetic and/or optical sensor for measuring said concentration of an entity in a digit. Additionally, it should also be clarified that any examples described below with reference to a finger are not limited to use only with a finger. In fact, it should be understood that these examples are suitable to be used with any digit such as a finger, thumb or toe.

As mentioned above, the pressure applied by the finger onto a sensor of a medical device configured to measure the blood glucose level can affect the accuracy of the measurement. If the pressure is too much or too little, or inconsistent with previous measurements, the blood glucose readings can be inaccurate. Therefore, in an example of the present invention a medical device for measuring a concentration of an entity (such as blood glucose level) in a finger is provided where the pressure of the finger applied to a sensor can be adjusted or controlled. Such an example, will now be described with reference to figure 1. In this example, a medical device 100 for measuring a concentration of an entity in a finger is provided. The device 100 comprises a housing 102 for receiving a finger of a user, the housing 102 comprising a base and a lid (not shown), and a connector (not shown) connecting the lid to the base. The device further comprises a processing circuitry 103 and a sensor unit 106. The processing circuitry 103 is configured to operate the sensor unit 106 for measuring a concentration of an entity in a finger of a user. The device 100 also comprises a pressure sensor 107 configured to determine the pressure applied by the finger onto the sensor unit 106. The processing circuitry 103 is further configured to adjust the lid relative to the base dependent on the determined pressure so that the pressure applied by the finger onto the pressure sensor 106 can be controlled or adjusted.

The pressure applied by the finger onto the pressure sensor 107 can be controlled in such a way that the right or optimal amount of pressure is applied during measurement of the concentration of an entity in the finger. In one example, the previous pressure applied by a finger onto the pressure sensor 106 is stored in a memory 105 such that for a subsequent measurement the lid is adjusted relative to the base so that the same pressure is achieved as the previous pressure, and once the right pressure has been achieved, a measurement is taken. In one example, the processing circuitry 103 is configured to receive a reading from the pressure sensor 107, and when the processing circuitry 103 determines that the reading falls within a predetermined range, the processing circuitry 103 is configured to send a signal to the sensor unit to measure a concentration of an entity in the finger.

Examples of the device shown in figure 1, will now be described with reference to figure 2. Here a medical device 200 is shown comprising the same features mentioned above and so a detailed description of these features will be omitted, however like for like reference numerals will be used. In one example, the medical device 200 further comprises a tourniquet 210 to be positioned at least partially around a tip of a finger so to control the blood flow to and from the finger. The tourniquet 210 is attached to the medical device 200, and in one example, it is attached to the base such that a finger is received between the base and the tourniquet 210. In one example, the tourniquet 210 is at least partially located around the tip of the finger, the distal phalanx or the middle phalanx. The tourniquet 210 is configured such that it can be shortened causing tightening around the finger. The tightening around the finger restricts blood flow to and from the finger. This means that for each measurement of a concentration of an entity, the amount of blood in the finger can be adjusted by the medical device 200 such that there is a consistent amount of blood for each measurement. The amount of blood is adjusted by either tightening or loosening the tourniquet 210. In one example, the tourniquet is connected to a motor 209 located in the medical device which tightens and loosens the tourniquet in response to a signal or command sent from the processing circuitry 103. Thus, the tourniquet may be considered to be automated.

The example shown in figure 2 may further comprise a blood volume sensor 211. An example of a blood volume sensor 211 may be a pulse-oximetry sensor. The blood volume sensor 211 senses the volume of blood in the finger that is located in the medical device. The volume of blood is important for accurate measurements of a concentration of an entity in the finger. When the blood volume sensor 211 has sensed the volume of blood it sends the information to the processing circuitry 103. The processing circuitry 103 then determines if the blood volume is too great or too little. If the blood volume is too great, the processing circuitry 103 will send a signal to the automated tourniquet member to be loosened. If on the other hand the blood volume is too little, the processing circuitry 103 will send a signal to the automated tourniquet member to be tightened.

In one example, the processing circuitry 103 determines the predetermined range of blood volume that should be in the finger for an accurate measurement of a concentration of an entity. The range may be based on the volume of blood present in the first ever measurement of a user. In this example, a user profile may be created upon set up of the medical device for a particular user. In another example, the predetermined range may be provided by a user input. Also this predetermined range can be associated with a user profile. The user profile and/or the predetermined range may be stored in the memory 105.

The medical device 200 may further comprise a fingerprint sensor 213. The fingerprint sensor 213 may be configured to identify the user such that the processing circuitry 103 can identify the user profile of a user and their associated ranges of blood volume and/or pressure that should be applied onto the sensor unit 106. The processing circuitry 103 can then control the tourniquet 210 and the motorised connector to achieve the desired blood volume and/or pressure before and/or during a measurement of a concentration of an entity. In one example, the fingerprint sensor 213 alternatively or additionally authenticates a user such that if the user is successfully authenticated, the medical device 200 can be used. However, if a user is not successfully authenticated, the medical device will not perform a measurement or provide access to stored information.

In another example, the fingerprint sensor 213 is configured to send the sensed information to the processing circuitry 103 and the processing circuitry 103 is configured to detect the orientation or position of the finger relative to the medical device 200. If the processing circuitry 103 determines that the finger is not aligned within a predetermined range the accuracy of a reading may be reduced. Therefore, the processing circuitry 103 may be further configured to signal to the user to re-adjust the finger in the medical device. This may be through a user interface displaying text or light prompting a user to correct the orientation of their finger. Once the orientation of the finger falls within a predetermined range of orientations, the processing circuitry 103 sends a signal to the sensor unit to measure a concentration of an entity in the finger. In an alternative embodiment, the processing circuitry 103 signals to the sensor unit 106 to measure a concentration of an entity regardless of the orientation of the finger but when the processing circuitry 103 processes the measurement received from the sensor unit 106, the processing circuitry takes into account the actual position of a finger and the desired position, and then applies a correction value to the concentration of the entity measured by the sensor unit 106.

In a further example, the connector in the medical device 200 is motorised. It may be driven by the motor 209 described in connection with the tourniquet 210, or alternatively it may be driven by a separate motor (not shown). Thus, when the processing circuit 103 receives a reading or information from the pressure sensor, and the processing circuit determines that the reading or pressure level falls outside a predetermined range, for example, the pressure is too low, the processing circuit sends a signal to the motor driving the connector to lower the lid closer to the base, so that the pressure of the finger applied to the sensor unit 106 increases. The pressure sensor 106 will then receive another signal from the processing circuit 103 to measure the pressure again, and after measuring the pressure sensor 107 will send back the measurement to the processing circuitry 103. Again, the processing circuity 103 will then determine if the pressure falls within the predetermined range and if not it will readjust the lid relative to the base until the desired pressure has been achieved. Once the desired pressure has been achieved, the processing circuit 103 will send a signal to the sensor unit 106 to measure the concentration of an entity in the finger.

As mentioned above, a factor that affects the accuracy of a non-invasive medical device configured to measure blood glucose levels in a finger is the volume of blood present in the fingers whilst the blood glucose level is being measured. An example of a medical device 300 for measuring a concentration of an entity in a finger addressing or improving the accuracy in view of blood volume will now be described with reference to figure 3. The medical device 300 comprises a housing 302 for receiving a finger of a user. The medical device further comprises a processing circuitry 303 and a sensor unit 306. The processing circuitry 303 is configured to operate the sensor unit 306 for measuring a concentration of an entity in the finger of the user. The medical device 300 further comprises a tourniquet 310 configured to be positioned at least partially around a tip of the finger to control the blood flow to and from the finger. The medical device 300 also comprises a blood volume sensor 311 configured to take a measurement indicative of the volume of blood in the finger. The blood volume sensor 311 sends the measurement to the processing circuitry 303 which is further configured to determine the volume of blood in the finger based on the measurement and to adjust the tourniquet 310 dependent on the determined volume of blood in the finger. This means that for each reading of a concentration of an entity, the amount of blood in the finger can be adjusted by the medical device 300 such that there is a consistent amount of blood for each reading. The amount of blood is adjusted by either tightening or loosening the tourniquet 310.

Examples of the device shown in figure 3, will now be described with reference to figure 4. Here a medical device 400 is shown comprising the same features mentioned above for figure 3, and so a detailed description of these features will be omitted, however like for like reference numerals will be used. In one example, the tourniquet 310 is attached to the medical device 300, and in a further example, the housing 302 of the medical device comprises a lid and a base connected via a connector, and the tourniquet 310 is attached to the base such that a finger is received between the base and the tourniquet 310. In another example, the tourniquet 310 is at least partially located around the tip of the finger, the distal phalanx or the middle phalanx. In one example, the tourniquet is connected to motor 409 located in the medical device which tightens and loosens the tourniquet in response to a command from the processing circuitry 303. If the processing circuitry 303 determines that the blood volume is too great in the finger for an accurate reading, the processing circuitry will send a command to the motor 309 which is configured to operate the tourniquet 310 so as to loosen the tourniquet. If the processing circuitry determines that the blood volume is too little in the finger for an accurate reading, the processing circuitry will send a command to the motor to tighten the tourniquet 310.

The blood volume sensor 306 of figure 4 may be a pulse-oximetry sensor. The volume of blood is important for accurate readings of a concentration of an entity in the finger.

When the blood volume sensor has sensed the volume of blood it sends the information to the processing circuitry 103 and thereafter the processing circuitry determines if the blood volume is too great or too little. Depending on the outcome, the processing circuitry operates the tourniquet as described above. The medical devices 300, 400 may further comprise any of the features described above with reference to figures 1 and 2 in connection with the tourniquet, the blood volume sensor and the processing circuitry.

In another example, the medical device 200 may further comprise a fingerprint sensor 413. The fingerprint sensor 213 may be configured according to any of the examples described in connection with medical device 200 in figure 2 and so a detail description will be omitted.

In another example, the device 400 also comprises a pressure sensor 407 configured to determine the pressure applied by the finger onto the sensor unit 306, and the processing circuitry 303 being further configured to adjust the lid relative to the base dependent on the determined pressure. By adjusting the lid relative to the base, the pressure applied by the finger onto the pressure sensor 306 can be controlled. In one example, the connector is motorised such that the lid can be adjusted relative to the base depending on the pressure sensed by the pressure sensor 407. The pressure sensor 407, lid, connector, base, motor and processing circuitry may be configured according to the various examples described above in connection with figures 1 and 2 and so a further

detailed description will be omitted.

As described above, one of the factors that affects the accuracy of a medical device configured to measure blood glucose levels in a finger is the orientation of the finger relative to the medical device. A small fraction of misalignment can cause the measurement to be inaccurate. In view of this, an example of a medical device 500 is provided where the orientation or alignment of a finger is taken into account. The example is shown in figure 5 and the medical device 500 comprises a housing 502 for receiving a finger of a user. The medical device 500 further comprises a processing circuitry 503 and a sensor unit 506. The processing circuitry 503 is configured to operate the sensor unit 506 for measuring a concentration of an entity in the finger. The medical device 500 further comprises a fingerprint sensor 513 for determining the orientation of the finger on or relative to the sensor unit. The processing circuitry 503 is further configured to determine if the orientation sensed by the fingerprint sensor falls within a predetermined range of orientations. In one example, when the medical device is initially set up for a new user, a user profile is created wherein their fingerprint is scanned by the fingerprint sensor 506. As their fingerprint is scanned, a "master fingerprint is created, and this master fingerprint and its orientation may act as a reference for any future readings of the medical device 500 wherein a measurement will only be performed if the orientation of the finger as determined by the fingerprint sensor 506 falls within a predetermined range relative to the master fingerprint. In an alternative embodiment the medical device 500 takes a measurement regardless of orientation but applies a correction factor to the measurement so as to compensate for the misalignment of the finger.

Examples of the medical device shown in figure 5, will now be described with reference to figure 6. Here a medical device 600 is shown comprising the same features mentioned above for figure 5, and so a detailed description of these features will be omitted, however like for like reference numerals will be used. In one example, the processing circuitry is further configured to send a signal to the sensor unit 506 to measure a concentration of an entity in the finger if the orientation of the finger falls within the predetermined range of orientations. In one example, the processing circuitry 503 will only send a signal to the sensor unit 506 to measure a concentration of an entity in the finger if the orientation of the finger falls within the predetermined range of orientations. When the finger is positioned such that it does not fall within the predetermined orientation, an indication can be sent or made to the user to correct the position of the finger. The indication can, for example, be through an interface showing text or a light.

In another example, the medical device 600 further comprises a tourniquet 610 to be positioned at least partially around a tip of a finger so to control the blood flow to and from the finger. The tourniquet 610 is attached to the medical device 600 and may be controlled by a motor 609 which upon receiving a command from the processing circuitry 503 tightens or loosens the tourniquet. The housing 502 may comprise a lid and a base, connected by a connector. The tourniquet 610 may be attached to the base such that a finger is received between the base and the tourniquet 610. The medical device 600 may further comprise a blood volume sensor 611. The tourniquet 610, the motor 609 and/or the blood volume sensor 611 may be configured according to any of the examples described previously with reference to figures 2, 3 and 4, and these components together with the processing circuitry 503 are configured to control the blood volume in the figure of a user so as to improve the accuracy of the measurements.

In one example, the medical device may comprise a pressure sensor 607configured to determine the pressure applied by the finger onto the sensor unit 506. The processing circuitry 503 may be further configured to adjust the lid relative to the base dependent on the determined pressure.

The components of the medical device 500, 600 described above may be configured according to any of the examples, alone or in any combination, described previously with reference to figures 1 to 4, and so a further detailed description has been omitted.

As described above, the processing circuitry 103, 303, 503 is configured to operate or communicate with the sensor unit 106, 306, 506, pressure sensor 107, 407, 607, fingerprint sensor 213, 413, 513, tourniquet 210, 310, 610, motor 209, 409, 609, blood volume sensor 211, 311, 611, and the memory 107, 305, 605.

The processing circuitry 103, 303, 503 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, custom processor, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and/or encoded logic operable to provide, either alone or in conjunction with other components, such as a memory, or any of the other components discussed above, measuring of concentration of an entity in a finger. For example, processing circuitry 103, 303, 503 may execute instructions stored in the memory. Such functionality may include measuring of concentration of an entity in a finger taking into consideration the pressure of a finger applied onto the sensor unit, the volume of blood in the finger, and/or the orientation of the finger relative to the medical device. In some examples, processing circuitry 103, 303, 503 may include a system on a chip (SOC).

The memory 105, 305, 605 may be considered to be a readable medium. The memory 105, 305, 605 may comprise any form of volatile or non-volatile computer readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), removable storage media (for example, a flash drive), and/or any other volatile or non-volatile, non-transitory device readable and/or computer-executable memory devices that store information, data, and/or instructions that may be used by processing circuitry 103, 303, 503. The memory 105, 305, 605 may store any suitable instructions, data or information, including a computer program, software, an application including one or more of logic, rules, code, tables, etc. and/or other instructions capable of being executed by processing circuitry 105, 305, 503. The memory 105, 305, 605 may be used to store any calculations made by processing circuitry 103, 303, 503 any data received from the sensory unit, fingerprint sensor, blood volume sensor or pressure sensor, and/or any data received via a user interface. In some embodiments, processing circuitry 103, 303, 503 and the memory 105, 305, 605 may be considered to be integrated.

It should also be understood that any of the medical devices described above is connectable to another device or network via a wireless protocol such as Wi-Fi, 3GPP network, Bluetooth, Zigbee, NFC or any other custom wireless connection and/or protocol.

The above examples can be implemented in various ways, and one example of an implementation will now be described with reference to figure 7. The example shown in figure 7 is a medical device 700 for measuring a concentration of an entity in a finger of a user. The medical device 700 comprises a housing having a base 720 and a lid 721, connected via a connector which in this example is a hinge 722. The hinge may be motorised such that the lid 721 can move up and down relative to the base 720. The lid 721 and the base 720 comprises a groove 723a, 723b so that the medical device can receive a finger whilst the lid is closed. In the groove 723b of the base, there may be a sensor platform 724. The sensor platform 724 may comprise an electromagnetic sensor 725, fingerprint sensor 726, optical sensor 727, blood volume sensor 728 and temperature sensor 729. At least two of these sensors take measurements of the finger received in the groove 723a, 723b of the medical device and are used to improve the accuracy of the measuring of the concentration of an entity in the finger.

The medical device 700 may further comprises a tourniquet 710. The tourniquet 710 may be attached to the base across the groove 723b such that the base and the tourniquet together form a closed loop around the finger. The tourniquet 710 may further be motorised such that the tourniquet can be tightened or loosened to control blood flow to and from the finger as described with reference to figures 1 to 6.

The medical device 700 further comprises a user interface (not shown) which may be located on the top of the lid 721 The medical device 700 further comprises a processing circuitry (not shown) according to any of the examples described above with reference to figures 1 to 6. In one example, the processing circuitry may be a digital processing unit.

The medical device 700 may further comprise a wireless communication circuit (not shown) enabling the device to communicate with another device or network via a wireless protocol such as Wi-Fi, 3GPP network, Bluetooth or NFC. The wireless communication unit may be for transferring data, update software and/or controlling the medical device with another device.

The different sensors of the sensor platform 724 will now be described in more detail.

The electromagnetic sensor 725 may comprise a radio frequency (RF) sensor and an RE transceiver circuit. Together they are configured to receive instructions from the processing circuitry to take an electromagnetic or radio frequency measurement of the finger and then send the measurement to the processing circuitry. The processing circuitry will then process the measurement (on its own or together with optical measurements) to determine a concentration of an entity in the finger. The electromagnetic sensor 725 may further comprise a pressure sensing circuit. The pressure sensing circuit is configured to measure the pressure applied to the electromagnetic sensor 725 and then send its measurement to the processing circuitry. If the processing circuitry determines that the pressure of the finger applied to the electromagnetic sensor 725 is too high or too low in order to get an accurate measurement as possible, the processing circuitry will send a signal to the motor driving the hinge to adjust the position of the lid accordingly. The pressure of the finger applied to the electromagnetic sensor 725 should fall within a predetermined range during the measurement of the concentration of an entity in the finger as described with reference to figures 1 to 6, in order for said measurement to be as accurate as possible. In one example, the motorised hinge is in a closed-loop system with the processing circuitry.

The optical sensor 727 may comprise a light source and a light detector operated by an analog/digital pre-conditioning circuit. The light source may comprise multiple light sources or a single light source. To take a measurement using the optical sensor 727, the processing circuit sends a signal to the analog/digital pre-conditioning circuit which in turn activates the light source and requests a measurement from the light detector.

Once the analog/digital pre-conditioning circuit has received the measurement, it processes the measurement converting it from an analog to digital signal or information. The analog/digital pre-conditioning circuit then sends the measurement in the form of a digital signal to the processing circuitry.

The blood volume sensor 728 may be a pulse-oximetry sensor. The blood volume sensor 728 detects the volume of blood in the finger received in the medical device 700. The blood volume sensor 728 may receive a signal from the processing circuitry to measure the blood volume present in the finger. Once the blood volume sensor 728 has taken the measurement, it sends it to the processing circuitry where the processing circuitry processes the measurements to determine if the volume of blood present in the finger is too great or too little for measuring the concentration of an entity in the finger as accurately as possible. If the volume of blood is determined to be too great, the processing circuitry will signal to the motor driving the tourniquet to loosen the tourniquet around the finger. On the other hand, if the volume of blood is determined to be too little, the processing circuitry will signal to the motor driving the tourniquet to tighten the tourniquet around the finger. The blood volume should fall within a predetermined range as discussed above with reference to figures 1 to 6 so as to get as accurate a measurement of the concentration of an entity as possible. The blood volume sensor 728 and the tourniquet 710 may be in a closed-loop system with the processing circuitry.

The fingerprint sensor 726 is configured to sense the fingerprint of a user. It can be configured to identify and/or authenticate a user as described with reference to figures 1 to 6 The temperature sensor 729 is configured to measure the temperature of the finger received in the medical device 700. The temperature of the finger may also affect the accuracy of the measurement of a concentration of an entity, and so the processing circuitry can be configured to take any temperature differences into account when determining the concentration of an entity.

Further explanations to the above examples will now be described.

It should be understood that the connector described herein may be a hinge as shown in figure 7. In other examples, the connector is differently configured in that it comprises motorised posts located at each or some of the corners or edges of the device. The posts are configured to guide the lid closer or further away from the base. In another example, the connector comprises a combination of motorised posts and a motorised hinge, either driven by the same motor or by separate motors.

It should also be understood that although the above examples are described to have a sensor unit or a sensor platform located on the base of the medical device, these can alternatively be located on the lid. More specifically, the sensor unit or the sensor platform can be located on the surface of the lid that faces the finger. In another example, some of the sensors of the sensor unit or sensors of the sensor platform are located on the surface of the base facing the finger and some on the surface of the lid facing the finger.

The examples described above may further comprise a medical device wherein the surfaces of the lid and/or the base facing the finger of a user can be formed out of a material that can be moulded to the contour of said user's finger. This means that the medical device can be customised to the shape of a user's finger so that the contact between the sensor unit/sensor platform and the user's finger can be maximised, furthermore, it also improves the pressure distribution. An example of such a material is a soft silicon material.

Example methods will now be described with reference to figures 8 to 10.

A method 800 performed by a medical device is shown in figure 8. The method is for measuring a concentration of an entity in a finger. The medical device comprises a lid and a base configured to receive a user's finger therebetween. The method comprises determining a pressure applied by a finger onto a sensor unit of the medical device and adjusting the pressure by moving the lid relative to the base, the method further comprises the sensor unit measuring a concentration of an entity in a finger 802. Operation 802 may occur before and/or during a sensor unit measures a concentration of an entity in said finger.

In an example, the method 800 comprises receiving a reading from a pressure sensor of the medical device, and when the reading falls within a predetermined range, the method further comprises sending a signal to the sensor unit to measure a concentration of an entity in the finger 803. The reading from the pressure sensor comprises information of the pressure applied by the user's finger onto the pressure sensor as well as the sensor unit.

The method 800 may further comprise controlling the blood flow to and from the finger 804. This may be achieved using a tourniquet positioned at least partially around a tip of the finger.

In one example, the method 800 comprises positioning a tourniquet at least partially around the finger. The tourniquet may be positioned where the distal phalanx or middle phalanx is located 805.

In another example, the method comprises measuring the volume of blood in the finger 806. This may be measured using a blood volume sensor.

In yet another example, the method comprises receiving a reading of blood volume in the finger from a blood volume sensor and adjusting the tourniquet based on the reading so as to increase or restrict blood flow to and from the finger 807.

In another example, the method 800 comprises determining an orientation of a finger relative to the sensor unit and/or medical device 807. This may be determined using a fingerprint sensor.

In yet a further example, the method 800 comprises receiving information of the orientation of a finger from a fingerprint sensor and when the orientation of a finger falls within a predetermined range of orientations, sending a signal to the sensor unit to measure a concentration of an entity in the finger 808.

The above described operations in relation to method 800, do not have to be performed in the order described above, the operations may be performed in various orders and some operations may be omitted.

Another method 900 performed by a medical device for measuring a concentration of an entity in a finger will now be described with reference to figure 9, the method comprises positioning a tourniquet of the medical device at least partially around a tip of a finger of a user to control blood flow to and from the finger, the method further comprises a sensor unit of the medical device measuring a concentration of an entity in the finger.902. This operation may occur before and/or during a sensor unit measures a concentration of an entity in said finger.

In one example, the method 900 further comprises measuring the volume of blood in the finger 903. This may be measured by a blood volume sensor of the medical device.

The method may further comprise determining the volume of blood in the finger based on the reading and adjusting the tourniquet dependent on the determined volume of blood in the finger 904 so as to increase or restrict blood flow to and from the finger.

This may be performed by a processing circuitry.

In another example, the method 900 comprises positioning the tourniquet at least partially around the finger where the distal phalanx or middle phalanx is located.

In another example, the method 900 comprises determining the pressure applied by the finger onto a sensor unit, and adjusting a lid relative to a base dependent on the determined pressure 905. The lid and the base form part of the medical device, and a user's finger is received in between the lid and the base.

In a further example, the method 900 comprises receiving a reading from a pressure sensor of the medical device, and when the reading falls within a predetermined range, the method further comprises sending a signal to the sensor unit to measure a concentration of an entity in the finger 906. This may be performed by a processing circuitry of the medical device. The reading from the pressure sensor comprises information of the pressure applied by the user's finger onto the pressure sensor as well as the sensor unit.

In yet another example, the method 900 comprises determining the orientation of the finger relative to the sensor unit and/or medical device 907. This may be determined by a fingerprint sensor of the medical device.

In yet a further example, the method 900 comprises receiving information of the orientation of a finger from the fingerprint sensor and when the orientation of a finger falls within a predetermined range of orientations, the method further comprises sending a signal to the sensor unit to measure a concentration of an entity in the finger 908.

The above described operations in relation to method 900, do not have to be performed in the order described above, the operations may be performed in various orders and some operations may be omitted.

Another example of a method 1000 performed by a medical device for measuring a concentration of an entity in a finger will now be described with reference to figure 10.

The method 1000 comprises determining the orientation of a finger relative to said medical device, and if the orientation of the finger falls within a predetermined range of orientations relative to the medical device, the method further comprises a sensor unit of the medical device measuring a concentration of an entity in the finger 1002. The orientation of the finger may be determined by a fingerprint sensor of the medical device. Furthermore, the orientation may be determined before and/or during measuring a concentration of an entity in said finger.

In one example, the method 1000 comprises a processing circuitry of the medical device sending a signal to the sensor unit to measure a concentration of an entity in the finger if the orientation of the finger falls within the predetermined range of orientations 1003.

The method 100 may further comprise controlling the blood flow to and from the finger 1004. This may be achieved using a tourniquet positioned at least partially around a tip of the finger.

In another example, the method 1000 comprises positioning a tourniquet of the medical device at least partially around a tip of the finger to control the blood flow to and from the finger 1005.

In yet another example, the method 1000 comprises positioning the tourniquet at least partially around the finger where the distal phalanx or middle phalanx is located.

In a further example, the method 10000 comprises measuring the blood volume in the finger 1006. This may be measured using a blood volume sensor.

In a further example, the method 1000 comprises receiving a reading of blood volume from a blood volume sensor and adjusting the tourniquet based on the reading so as to increase or restrict blood flow in the finger 1007. This may be performed by a processing circuitry.

In another example, the medical device comprises a housing having a base and a lid, and a connector connecting the lid to the base, and a pressure sensor, wherein the method 1000 comprises determining the pressure applied by the finger onto the sensor unit, and adjusting the lid relative to the base dependent on the determined pressure 1008.

In yet another example, the method 1000 comprises receiving a reading from the pressure sensor and when the reading falls within a predetermined range, sending a signal to the sensor unit to measure a concentration of an entity in the finger 1009. The reading from the pressure sensor comprises information of the pressure applied by the user's finger onto the pressure sensor as well as the sensor unit.

The above described operations in relation to method 1000, do not have to be performed in the order described above, the operations may be performed in various orders and some operations may be omitted.

The examples herein may be implemented in hardware, or as software modules running on one or more processors. The methods 800, 900, 1000 may also be carried out according to the instructions of a computer program, and the present invention also provides a computer readable storage medium having stored thereon a program for carrying out any of the methods described herein. A computer program embodying the methods may be stored on a computer-readable medium, or it could, for example, be in the form of a signal such as a downloadable data signal provided from an Internet website, or it could be in any other form.

Furthermore, the methods 800, 900, 1000, as illustrated by the above examples, may be conducted in a medical device. Figure 11 illustrates an example of a medical device which may execute the methods of the present invention, for example on receipt of suitable instructions from a computer program. Referring to figure 11, the medical device 1101 comprises a processor 1102 and a memory 1103. The memory 1103 contains instructions executable by the processor 1102 such that the medical device is operative to carry out the method 800, 900, 1000.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim, "a" or "an" does not exclude a plurality, and a single processor or other unit may fulfil the functions of several units recited in the claims. Any reference signs in the claims shall not be construed so as to limit their scope.

Claims

Claims 1 A medical device for measuring a concentration of an entity in a digit, the device comprising; a housing for receiving a digit of a user, the housing comprising a base and a lid, and a connector connecting the lid to the base, a processing circuitry and a sensor unit, the processing circuitry is configured to operate the sensor unit for measuring a concentration of an entity in the digit, a pressure sensor configured to determine the pressure applied by the digit onto the sensor unit, and the processing circuitry being further configured to adjust the lid relative to the base dependent on the determined pressure.
2. A medical device according to claim 1, further comprising a tourniquet to be positioned at least partially around a tip of the digit to control the blood flow to and from the digit.
3. A medical device according to claim 2, wherein the tourniquet is configured to be positioned at least partially around a finger where the distal phalanx or middle phalanx is located.
4. A medical device according to claim 2 or 3, further comprising a blood volume sensor configured to measure the volume of blood in the digit.
5. A medical device according to claim 4, wherein the processing circuitry is configured to receive a reading from the blood volume sensor and adjust the tourniquet based on the reading so as to increase or restrict blood flow in the digit.
6. A medical device according to any preceding claim, wherein the processing circuitry is configured to receive a reading from the pressure sensor and when the reading falls within a predetermined range, the processing circuitry is configured to send a signal to the sensor unit to measure a concentration of an entity in the digit.
7. A medical device according to any preceding claim, further comprising a fingerprint sensor for determining an orientation of the digit relative to the sensor unit.
8. A medical device according to claim 7, wherein the processing circuitry is configured to receive information of the orientation of a digit from the fingerprint sensor and when the orientation of a digit falls within a predetermined range of orientations, the processing circuitry is further configured to send a signal to the sensor unit to measure a concentration of an entity in the digit.
9. A medical device for measuring a concentration of an entity in a digit, the device comprising; a housing for receiving a digit of a user, a processing circuitry and a sensor unit, the processing circuitry is configured to operate the sensor unit for measuring a concentration of an entity in the digit, a tourniquet configured to be positioned at least partially around a tip of the digit to control blood flow to and from the digit, a blood volume sensor configured to take a reading indicative of the volume of blood in the digit, and the processing circuitry being further configured to determine the volume of blood in the digit based on the reading and to adjust the tourniquet dependent on the determined volume of blood in the digit.
10. A medical device according to claim 9, further comprising a fingerprint sensor for determining the orientation of the digit on the sensor unit.
11. A medical device according to claim 10, wherein the processing circuitry is configured to receive information of the orientation of a digit from the fingerprint sensor and when the orientation of a digit falls within a predetermined range of orientations, the processing circuitry is further configured to send a signal to the sensor unit to measure a concentration of an entity in the digit.
12. A medical device for measuring a concentration of an entity in a digit, the device comprising; a housing for receiving a digit of a user, a processing circuitry and a sensor unit, the processing circuitry is configured to operate the sensor unit for measuring a concentration of an entity in the digit, a fingerprint sensor for determining the orientation of the digit on the sensor unit, and the processing circuitry further being configured to determine if the orientation of the digit falls within a predetermined range of orientations.
13. A medical device according to claim 12, wherein the processing circuitry is further configured to send a signal to the sensor unit to measure a concentration of an entity in the digit if the orientation of the digit falls within the predetermined range of orientations.
14. A medical device according to claims 12 and 13, further comprising a tourniquet to be positioned at least partially around a tip of the digit to control the blood flow to and from the digit
15. A medical device according to claim 14, wherein the tourniquet is configured to be positioned at least partially around a finger where the distal phalanx or middle phalanx is located.
16. A medical device according to any of claims 12 to 15, further comprising a blood volume sensor configured to measure the volume of blood in the digit.
17. A medical device according to claim 16, wherein the processing circuitry is configured to receive a reading from the blood volume sensor and adjust the tourniquet based on the reading so as to increase or restrict blood flow in the digit.
18. A medical device according to any of claims 9 to 17, wherein the housing comprises a base and a lid, and a connector connecting the lid to the base, and a pressure sensor configured to determine the pressure applied by the digit onto the sensor unit, and the processing circuitry being further configured to adjust the lid relative to the base dependent on the determined pressure.
19. A medical device according to claim 18, wherein the processing circuitry is configured to receive a reading from the pressure sensor and when the reading falls within a predetermined range, the processing circuitry is configured to send a signal to the sensor unit to measure a concentration of an entity in the digit.
20. A medical device according to any of claims 1-9, 18 and 19, wherein the connector is motorised and operated by the processing circuitry.
21. A medical device according to any preceding claim, wherein the sensor unit comprises a radio frequency sensor and/or an optical sensor.
22. A method performed by a medical device for measuring a concentration of an entity in a digit, the medical device comprises a lid and a base, the method comprises determining a pressure applied by a digit onto a sensor unit of the medical device and adjusting the pressure by moving the lid relative to the base, the method further comprises the sensor unit measuring a concentration of an entity in a digit.
23. A method performed by a medical device for measuring a concentration of an entity in a digit, the method comprises positioning a tourniquet of the medical device at least partially around a tip of a digit of a user to control blood flow to and from the digit, the method further comprises a sensor unit of the medical device measuring a concentration of an entity in the digit.
24. A method performed by a medical device for measuring a concentration of an entity in a digit, the method comprises determining the orientation of a digit relative to said medical device, and if the orientation of the digit falls within a predetermined range of orientations relative to the medical device, the method further comprises a sensor unit of the medical device measuring a concentration of an entity in the digit.