Patent Application
20130344609
The present Invention relates to a portable electronic device and to a method for operating a portable electronic device.
Today's smart phones or tablet computers contain a couple of sensors such as, for example, a gyroscope or an acceleration sensor used for detecting an orientation of the device display for having the content to be displayed adapted to such orientation.
In general, chemical sensors are known for detecting an analyte in a gas or a liquid, collectively denoted as fluid. When integrating a chemical sensor into a portable electronic device, it is a challenge to meet a point in time for taking a reading by the chemical sensor at which point in time the chemical sensor already is sufficiently exposed to the fluid to be analyzed.
Hence, it is desired to determine a point in time suitable for taking a chemical sensor reading in a portable electronic device.
According to a first aspect of the present invention, a portable electronic device is provided comprising a chemical sensor being sensitive to at least one analyte, and a trigger sensor providing a signal. A control unit is provided for triggering a sampling of a chemical sensor reading subject to the signal of the trigger sensor:
Preferred embodiments of the first aspect contain one or more of the following features:
According to another aspect of the present invention a portable electronic device is provided, comprising a chemical sensor being sensitive to at least one analyte and providing an output signal, and a control unit for triggering a sampling of a chemical sensor reading subject to the output signal of the chemical sensor.
In a preferred embodiment, the chemical sensor comprises multiple cells being sensitive to different analytes, and wherein the control unit is adapted to trigger the sampling of the chemical sensor reading subject to the output signal of at least one of the chemical sensor cells.
According to a further aspect of the present invention, a method is provided for operating a portable electronic device containing a chemical sensor being sensitive to at least one analyte and containing a trigger sensor, the method comprising monitoring a signal supplied by the trigger sensor, and subject to the signal of the trigger sensor taking a chemical sensor reading for detecting one or more of a presence and a concentration of the at least one analyte in a fluid supplied to the chemical sensor.
Preferred embodiments of this aspect contain one or more of the following features:
According to another aspect of the present invention, a method is provided for operating a portable electronic device containing a chemical sensor being sensitive to at least one analyte and providing an output signal, the method comprising monitoring the output signal of the chemical sensor, and subject to the output signal of the chemical sensor taking a chemical sensor reading for detecting one or more of a presence and a concentration of the at least one analyte in a fluid supplied to the chemical sensor.
According to a further aspect of the present invention, a computer program product is provided comprising a computer readable medium containing computer program code for implementing a method according to any one of the previous embodiments when being executed on a control unit.
Embodiments of the present invention will be described in more detail with reference to the annexed drawings, wherein the Figures show:
A chemical sensor preferably comprises a layer that is sensitive to one or more analytes a presence and/or a concentration of which is desired to be detected in a gas supplied to the chemical sensor. There may be a single sensitive layer made from a uniform material for interacting with the one or more analytes. Or there may be multiple sensitive layers made from different materials, for example, for interacting with different analytes. The chemical sensor performs a detection of chemical substances or compounds which are also denoted as analytes contained in a gas, or possibly in a fluid including liquids. Analytes may be, for example, CO2, NOX, ethanol, CO, ozone, ammonia, formaldehyde, or xylene without limitation.
In a preferred embodiment, the sensitive layer may contain a metal-oxide material, and in particular a semiconducting metal oxide material. Such metal oxide material may include one or more of tin oxide, zinc oxide, titanium oxide, tungsten oxide, indium oxide and gallium oxide. Such metal oxides may be used for the detection of analytes such as VOCs, carbon monoxide, nitrogen dioxide, methane, ammonia or hydrogen sulphide. Metal-oxide sensors are based on the concept that gaseous analytes interact with the metal oxide layer at elevated temperatures of the sensitive layer in the range of more than 100° Celsius, and specifically between 250° C. and 350° Celsius. As a result of the catalytic reaction, a conductivity of the sensitive layer may change which change can be measured. Hence, such chemical sensors are also denoted as high temperature chemoresistors for the reason that a chemical property of the analyte is converted into an electrical resistance at high temperatures of the sensitive layer.
Hence, a chemical sensor may in one embodiment comprise at least one sensor material, e.g. in form of a layer, an analyte may interact with and as such modify an electrical property of the sensor material such as its electrical conductance. Then, the electrical property of a combination of the analyte and the sensor material is measured and allows a conclusion as to a presence of the analyte, such as by way of comparison to a property of the sensor material measured without the presence of the analyte. It is noted that for different analytes—which may be different chemical elements or chemical compounds—it is not required to always measure the same property per analyte. Different properties may be measured for different analytes.
Specifically, the chemical sensor may be a gas sensor for detecting one or more substances in a gas, and specifically in the air surrounding the portable electronic device. Hence, in a sample application it may be of interest to identify if such air may contain analytes the chemical sensor is prone to. Other applications may include the detection of toxic gases, the detection of ethanol in a users breath, or the detection of other substances.
In case the chemical sensor is sensitive to multiple different analytes the chemical sensor may be embodied as a sensor array. Such sensor array may comprise multiple sensor cells, wherein each sensor cell may provide a sensor material, e.g. in form of a layer which is also denoted as sensitive layer, an analyte may interact with. In response to the interaction an electrical property of the sensor material such as its electrical conductance, may change which principle preferably is applied in metal oxide chemical sensors. In such scenario, the sensor array may comprise a single heater for all sensor cells, or may comprise multiple heaters, wherein each heater may be assigned for heating a group of sensor cells or an individual sensor cell, or the corresponding sensitive layer respectively.
In another embodiment, the chemical sensor may comprise a single sensor cell, e.g. with a single layer, which however, may be sensitive to multiple different analytes under different operating conditions. For example, the sensor cell may mainly be sensitive to a first analyte x when being heated to a first temperature tx, and may mainly be sensitive to a second analyte y when being heated to a second temperature ty which is different from the first temperature tx. In another variant, a sensor array may comprise multiple sensor cells wherein at least one of the multiple sensor cells—and in another variant preferably all of the multiple sensor cells—is/are designed such that such cell/s may mainly be sensitive to different analytes under different operating conditions such as under different temperatures. In such specific embodiment, each of such sensor cell/s may be provided with an individual heater.
The chemical sensor preferably is arranged inside a housing of the portable electronic device. An access opening may be provided in the housing for exposing the chemical sensor to a fluid to be analyzed, and specifically to a gas to be analyzed.
Hence, any portable electronic device such as a mobile phone, and in particular a smart phone, a handheld computer, an electronic reader, a tablet computer, a game controller, a pointing device, a photo or a video camera, or a computer peripheral—which listing is not limited—may in addition to its original function provide chemical information as to its environment. The user may learn about chemical substances and compositions present in the devices surroundings and/or his/her breath, and may use, transmit or else further analyse such information. For the reason that such portable electronic device typically includes interfaces to a remote infrastructure, such information may be transmitted elsewhere and used elsewhere. In an alternative, the user himself/herself may benefit from the information provided by the chemical sensor in that actions can be taken in response to detected analytes, including but not limited to analytes representing toxic substances. Such portable electronic device may primarily be designed for computing and/or telecommunication and/or other tasks in the IT arena, and now be enhanced by a function of providing chemical information.
The chemical sensor preferably may be arranged in a compartment of the housing wherein the access opening may provide access to the chemical sensor in the compartment. Therefore, a gas to be analyzed is required to diffuse into the compartment. Such process may take some time. If, however, a chemical sensor reading is taken too early at e.g. a point in time when the gas of interest may not have yet reached the chemical sensor or may have reached the chemical sensor only to an insufficient degree, the chemical sensor reading may not be correct and reflect a measurement value not representing the current analyte concentration in the gas. Hence, the timing of taking a reading by the chemical sensor is important.
The terms “taking a chemical sensor reading” and “triggering a sampling of a chemical sensor reading” may include accepting or using a measurement value supplied by the chemical sensor, or may include measuring a value and accepting or using said value. Acceptance or use of a reading, i.e. is a measurement value, includes a usage of the chemical sensor reading for the purpose the reading was taken, e.g. for displaying the reading to the user, for further processing of the value, for forwarding the value etc. In case the chemical sensor continuously supplies readings in form of an output signal—e.g. when a voltage is permanently applied to a sensitive layer of a chemical sensor—taking the reading including triggering taking the reading may include utilizing the present reading for the very purpose of the reading or utilizing a reading defined with respect to the time of the trigger while other readings outside such specification may be discarded. However, taking a reading or triggering a sampling of a reading shall not be limited to the usage of a single reading at the trigger point in time. Instead, taking the reading may include the usage of multiple present, past and/or future readings, for example, for building an average value amongst the readings taken according to a specification. In another embodiment, at the trigger point in time an integration of readings of the chemical sensor is started, for example, for a defined period in time, which integration value may finally be the value of interest. In case the chemical sensor is not continuously operative in providing measurement values, taking the reading including triggering taking the reading may include activating a measurement, which, for example, may include applying a voltage to the sensor layer, etc., and making use of the measured value.
The point in time at which a chemical sensor reading is taken depends on a signal of at least a trigger sensor. The trigger sensor may be a sensor separate to the chemical sensor. Or, the trigger sensor may be formed by elements of the chemical sensor itself. The trigger sensor may not necessarily be solely provided for the purpose for triggering the taking of a reading of the chemical sensor. Instead the trigger sensor may be represented by a sensor present in the portable electronic device for a different purpose and nay be used additionally for triggering the taking of the reading of the chemical sensor. The trigger sensor is provided in the portable electronic device, and may, for example, be a humidity sensor and/or a temperature sensor. The trigger sensor preferably is arranged and designed for allowing a conclusion that based on its signal the fluid to be analyzed is believed to have sufficiently diffused into the compartment yet, such that the chemical sensor is sufficiently exposed to the fluid for detecting the presence and/or concentration of an analyte in the gas. Hence, it is preferred that such trigger sensor may either detect the presence of the gas, preferably in a different way the chemical sensor does, or may allow drawing the conclusion that the fluid not likely has diffused to the chemical sensor.
In one embodiment, the trigger sensor may be a sensor for sensing a humidity of a gas in the environment of the humidity sensor, wherein the humidity sensor may preferably be arranged in the same compartment as the chemical sensor. Subject to the application, the gas to be analyzed may include a humidity different to an environmental gas. If, for example, the chemical sensor shall be used for analyzing the breath of a user exhaling at the device, then the relative humidity in the compartment increases owed to the users breath which is more humid than the environmental air. Specifically, when a signal of the humidity sensor exceeds a threshold indicating an increased humidity in the compartment, the chemical sensor reading taking may be triggered since it is assumed that the user presently not only exhales at the portable electronic device but the compartment for the chemical sensor and the humidity sensor is already filled by such breath. In another embodiment, an increase in humidity over time or an exceeding of the threshold by the humidity for a determined period in time may trigger the sampling of the chemical sensor reading given that compared to a slow environmental change in humidity a swift change in humidity may result from the user exhaling at the portable electronic device. The threshold used, as well as any other threshold used in connection with any trigger sensor, may be a fix threshold, or may be a variable threshold, or may be a threshold with a tolerance, etc.
In another embodiment, the trigger sensor may be a temperature sensor. The chemical sensor may be comprised in a semiconductor chip in combination with an integrated circuit arrangement. The integrated circuit arrangement may be designed for pre-processing the chemical sensor readings or for evaluation of the chemical sensor readings. The temperature sensor may be arranged for measuring a temperature at least of a part of the integrated circuit arrangement. Any gas circulating over the integrated circuit may change the temperature in this area which in turn may indicate a sufficient exposure of the chemical sensor to the gas to be measured. Such temperature sensor may anyway be provided in the semiconductor chip for monitoring a temperature of active elements in the integrated circuit.
In general, the trigger sensor may be integrated in the same chip together with the chemical sensor, preferably in a semiconductor chip. The semiconductor chip may be manufactured in a CMOS process and the chemical sensor structure and/or trigger sensor structures may be applied to the same semiconductor chip by a suitable manufacturing process, such as a MEMS process.
In another embodiment, the chemical sensor comprises a sensitive layer and a heater for heating the sensitive laver. In case the sensitive layer is made from metal oxide, such sensor forms a metal oxide sensor which becomes sensitive to the subject analyte when being heated to a sufficient temperature. Preferably, the heater and the sensitive layer are arranged on a thermally isolating part of the chip, such as on a bridge formed by thinning a substrate of the chip. By means of applying a temperature sensor for measuring a temperature of the sensitive layer or of the bridge, the arrangement can be used for measuring an air flow over said sensitive layer or of said bridge. Given that an air flow cools or heats the temperature of the sensitive element or the bridge, either such air flow causes a temperature deviation that can be measured by the temperature sensor, or a heating power may be taken as a measure for the air flow in case the temperature of the sensitive layer or the bridge is controlled to a constant value. The presence of a sufficient airflow may be taken as an indicator for a sufficient gas supply to the chemical sensor, for example, by the user exhaling at the access opening in the housing.
In another embodiment, the trigger sensor may be a gyroscope or an acceleration sensor, for example. On the one hand, detecting a rotational or translational movement of the portable electronic device by the gyroscope or the accelerometer respectively may represent a sufficient shaking of the portable electronic device which may be taken as an indicator for a sufficient gas supply to the chemical sensor based on the assumption that by shaking the device the gas better diffuses into the compartment. On the other hand, the gyroscope or the accelerometer may also be used as indicator that there is not sufficient gas supplied to the chemical sensor, for example, when the access opening is orientated at a direction where the user cannot exhale at.
In a preferred embodiment, a third sensor may be provided for determining a triggering point in time for taking a chemical sensor reading. The third sensor may again be preferably one of a humidity sensor, a temperature sensor, a flow sensor, a gyroscope or a pressure sensor, wherein the third sensor preferably relies on a different measuring principle than the trigger sensor. For example, both, a humidity sensor and a temperature sensor may be used for triggering the chemical sensor reading. The signal may either individually be evaluated, for example, versus a threshold, wherein the chemical sensor reading may only be taken, when both signals exceed their associate threshold. Or the signals of the trigger sensor and the third sensor may be combined and the chemical sensor reading may be triggered when the combined signal fulfils a condition.
In another embodiment, the trigger sensor may be represented by the chemical sensor itself, or by a cell of the chemical sensor being embodied as chemical sensor array comprising multiple sensor cells. In one example, in case an exhalation airstream of a user shall be analyzed in view of ethanol, the ethanol sensor may be embodied as one cell of the chemical sensor array. Another cell may be embodied for detecting CO2. The CO2 detecting cell may provide a signal when the user exhales at the chemical sensor. Whenever there is a sufficient concentration measured by the CO2 sensor cell, a reading of the ethanol sensor cell may be sampled under the assumption, that the chemical sensor is sufficiently exposed to the users breath. The trigger for a multi-cell chemical sensor may preferably trigger sensor readings at all sensor cells.
Preferably, a user may trigger a chemical sensor measurement by selecting a corresponding “app” or by an appropriate input at the portable electronic device.
In a preferred embodiment, if the sensor signal of the trigger sensor has not fulfilled the trigger condition after a defined period in time, for example after the chemical measurement has been started by a user, a warning signal may be issued to the user. Such warning signal may include a message on a display of the mobile phone and may include a request for blowing more strongly at the mobile phone, or for blowing at another area of the mobile phone, preferably where the chemical sensor resides. Any other feedback may be given to the user during an evaluation of the signal of the trigger sensor.
Same or similar elements are referred to by the same reference numerals across all Figures.
In a preferred embodiment, and as shown in the partial side cut of a lower part of a mobile phone 3 in
While there are shown and described presently preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practised within the scope of the following claims.
