Introduction The present invention relates to a mat or coaster, upon which an object such as a container may be placed, a coaster for a hot liquid container such as a cup or a placemat for a plate or dish, and to a cover or lid for food and drinks or a cupholder.

Background to the Invention

Mats such as placemats, coasters and the like are used in homes, restaurants, cafes, offices and elsewhere to protect a surface underneath a container such as a cup, glass, plate or the like. In general, without placing a mat between the surface and the container, the surface may become marked or damaged particularly if the bottom surface of the container which is in contact with the surface is wet or hot.

Liquid receiving containers include items such as glasses, cups, mugs, bowls, jugs, flasks beakers or the like and may be made from any suitable material such as glass, plastic, ceramic, metal, paper or cardboard.

When a liquid is poured into the container, it is in full direct contact with the inside surface of the container and as a consequence, the temperature of the container and the liquid moves toward thermal equilibrium relatively quickly, especially when the container is metal and even when the container is made from an insulator such as ceramic or glass. Heat transfer between the liquid and the container is of particular importance when the liquid in the container is significantly hotter than room

temperature.

Fast food outlets, coffee shops and the like sell hot drinks such as coffee, tea and hot chocolate in paper cups which are often lined with plastic or wax. In general, such cups have a lip at the top to which a lid may be connected and the bottom of the surface has a circular rim which rests upon a surface and ensures that the bottom of the liquid containing volume of the cup is not in direct contact with the surface, so as to reduce heat transfer to the surface. Typically, hot drinks are served at around 65°C but are brewed at higher temperatures, depending upon the beverage, of approaching 100 °C.

In addition, customers who want a takeaway drink may prefer to receive a hotter drink if there is to be a significant amount of time between receiving the drink and consuming it.

In all cases, the hotter the liquid, the greater the risk is that a person will be scalded if the drink is spilled. Accordingly it would be desirable to create a device which allows for the easy measurement of the temperature of the drink as it is served.

An obvious solution to this problem would be to use a thermometer to directly measure the liquid temperature. However, it would be unappealing, impractical and potentially very dangerous for consumers to have a thermometer inserted into their drink.

Summary of the Invention

It is an object of the present invention to provide a coaster, mat cover or tray which measures the temperature of a container and/or the liquid contained within the container.

In accordance with a first aspect of the invention there is provided a mat for protecting a surface from heat emitted from a container sucg as a cup or plate, the mat comprising: a sensor for detecting the heat emitted by an object operatively, the sensor being connected to the mat;

a housing into which the sensor is fitted;

a processor which calculates the temperature of the object based upon the heat detected by the sensor; and

an output signal which provides a measure of temperature of the object. Preferably, the sensor is a temperature sensor.

Preferably, the sensor comprises a plurality of detectors positioned across the surface of the mat.

Preferably, the present invention measures radiated heat detected by the sensor and therefore is not dependent upon physical contact between the object and the sensor which would be required for temperature measurement using convection or conduction.

Preferably, the temperature sensor measures infra-red radiation.

Preferably, the sensor measures the frequency and/or intensity of the emitted infra-red radiation.

Optionally, the sensor measures the infra-red radiation indirectly by measuring the increase in thermal energy in the sensor.

Preferably, the sensor comprises a Fresnel lens which focuses IR radiation for detection.

Preferably, the mat is water resistant so as to prevent water ingress. Preferably, the mat is heat resistant to 120°C.

Preferably, the mat has an upper surface for receiving the object and a lower surface for sitting on a surface such as a table.

Preferably, the mat coaster may be of any suitable shape, typically, round, oval, square or rectangular. Preferably, the mat has a surface area which is sized to receive the base of a cup or mug.

Preferably, the mat surface area is between 25cm ² and 150cm ² .

Preferably, the mat may be of any suitable shape, typically, round, oval, square or rectangular.

Preferably, the mat has a surface area which is sized to receive the base of a plate or serving dish.

Preferably, the mat surface area is between 150cm ² and 900cm ² .

Preferably, the housing is integrally formed with the mat.

Preferably, the housing comprises a recess in the mat.

Preferably, the sensor is fitted into a recess in the housing. Preferably, the housing has an outwardly facing transmission window which is substantially transparent to infra-red radiation.

Preferably, the transmission window comprises a suitable plastic. Optionally, the transmission window comprises a suitable glass.

Preferably, the transmission window is a filter which transmits radiation of a predetermined wavelength through the window to the sensor. Preferably, the filter transmits radiation having a central bandwidth between 7 and 14 pm. More preferably, the filter transmits radiation having wavelength between 8 and 10 μηη.

Optionally, the transmission window is uncovered, thereby exposing the sensor directly to the object from within the recess.

Preferably, the processor calculates the temperature of the object based upon the measured frequency and intensity of the infra-red radiation.

Optionally, the processor calculates the temperature of the object based upon data received from the sensor.

Optionally, the processor calculates the temperature of the object based upon the increase in thermal energy in the sensor. Preferably, the processor comprises a microcontroller.

Preferably, the processor indicates temperature to within ±10°C

Preferably, the processor, indicates temperature to within ±5°C

Preferably, the processor, indicates temperature to within ±1 °C

Preferably, the output signal is received by a display positioned on the mat or coaster. Optionally, the display comprises a plurality of light emitting diodes (LEDs), selective illumination of which provides an indication of temperature.

Optionally, the display comprises 3 LEDs in pulse width modulation mode. Optionally, the display comprises 8 LEDs in on/off configuration. Preferably, the mat or coaster has a battery power source.

Optionally, the battery is rechargeable. Optionally, the power source comprises a solar array.

Optionally, the output signal may be transmitted to an external receiver to provide a temperature reading. Preferably, the output signal is transmitted using the Bluetooth® communications protocol.

Preferably, the output signal is transmitted using the WI-FI communications protocol. Optionally, the mat or coaster is sized to fit into a car cup holder.

Preferably, the processor is configured to allow a user to define a preferred temperature range.

Optionally, the processor is provided by a software application on a computing means.

Preferablly. the computing means is a cellular phone, hand held computing device, tablet computer or laptop computer.

Preferably, the software application further comprises a graphical user interface upon which temperature information is displayed.

Preferably, the graphical user interface provides

information targeted to the user. In accordance with a second aspect of the invention there is provided a tray containing the technical features of the mat as defined above.

In accordance with a third aspect of the invention there is provided a lid or cover for a plate, bowl or cup containing the technical features of the mat as defined above.

In accordance with a fourth aspect of the invention there is provided a car cup holder containing the technical features of the mat as defined above. In accordance with a fifth aspect of the invention there is provided a software application for use with a mat, tray, lid, cover or cup holder as claimed in claims 1 to 54, the software application comprising program instructions for the following process:

receiving temperature information temperature from a device in accordance with claims 1 to 54,

displaying the information graphically or aurally on a device upon which the software application is loaded; and

displaying advertisements and other information when the application is open.

Preferably, the software application alerts the user when the temperature falls below a threshold value.

It will be appreciated that the form of the invention as a mat or cover provides a suitable means for detecting the temperature of the contents of the container by being in close proximity to the contents of the container.

Brief Description of the Drawings

The present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a graph which plots the relationship between light intensity and wavelength for radiation emitted from an object;

Figures 2A and 2B show a side view and a plan view respectively of a first embodiment of a coaster in accordance with the present invention;

Figure 3 is a flow diagram with graphs which show stages in the transmission of infrared radiation from source to sensor; Figure 4 is a block diagram which shows the sensor pack used in the embodiments described herein;

Figure 5 is a set of 3 graphs which show the response of a set of 3 LEDs to temperature under the control of the microcontroller;

Figure 6 is a flow diagram which describes the operation of firmware in an embodiment of the present invention;

Figure 7A and 7B show a side view and a plan view respectively of a second

embodiment of a mat in accordance with the present invention; and

Figures 8A. and 8B show a side view and a plan view respectively of a third

embodiment of a coaster in accordance with the present invention wirelessly connected to an output device Figure 8C and figure 8D is a perspective view of a beverage cup on the coaster of figure 8A and 8B.

Detailed Description of the Drawings

The present invention provides a place mat or coaster which contains a sensor and an output which provides a user with a measure of the temperature of an object which is operatively connected to the coaster or mat. A coaster is a type of mat which is typically used for small items such as drinks containers.

In the following preferred embodiments of the present invention, infra-red radiation is measured either through direct detection of the frequency or wavelength and intensity of the radiation or via the Seebeck Effect.

In general, there are three modes of heat transfer:

• Conduction

· Convection

Radiation

All heat transfer processes occur by one or more of these three modes. Conduction

Conduction is the transfer of heat in stationary media. It is the only mode of heat flow in solids but can also take place in liquids and gases. It occurs as the result of molecular collisions (in liquids) and atomic vibrations (in solids) whereby energy is moved, one molecule at a time, from higher temperature sites to lower temperature sites. Convection

Convective heat transfer takes place in a moving medium and is almost always associated with transfer between a solid and a moving fluid (such as air).

Radiation

Radiative heat transfer is unlike the other two modes in several respects:- It can take place across a vacuum.

It occurs by electromagnetic emission and absorption and at the speed of light. The energy transferred is proportional to the fourth power of the temperature difference between the objects. When infrared radiation is absorbed by a sensor, the object becomes hotter because its thermal energy increases. Absorption of infrared radiation by surface molecules accelerates their motion. As the movement of molecules in a material increases, the thermal energy of the material increases and the temperature change is converted into electricity (The Seebeck Effect).

Figure 1 is a graph 1 which illustrates Wein's law. The graph 1 plots the wavelength of electromagnetic radiation on the X axis 3 against the intensity of the electromagnetic radiation on the Y axis 5. Wein's Law allows us to determine the temperature of any object by the peak wavelength of light emitted which is shown for curves 7 and 9 by maxima 1 1 and 13 respectively For an object at 80°C, the wavelength of the light will be around 8.2μητι, and for an object of around 25°C the wavelength of the light will be around 9.7μηη. Therefore to detect temperatures in this range the window must be able to pass wavelengths from around 8μιη to 10μηι, which is in the range known as Long Wavelength Infrared (LWIR).

Figures 2a and 2b show a side and plan view of an embodiment of a coaster in accordance with a first embodiment of the present invention. Both figures show a coaster 21 which has a housing 23 in which is contained a sensor pack 25. Window or IR filter 29 is positioned on the top surface of the coaster 21 ; this being the surface onto which an object would be placed to detect its temperature. In addition indicator lights 27 are provided to show a measure of the detected temperature.

The coaster is made from a suitable heat and water resistant material. It is known that the diameter of objects such as cups and mugs vary in size. In order to accommodate containers of different sizes, a diameter of 20mm was chosen in this embodiment of the invention. The area of the coaster upon which the container is to be placed is identified on the upper surface of the coaster because placement of the container correctly upon the coaster improves the accuracy of the measurement. In this example, the coaster is substantially circular in plan, but other shapes may be used. The depth of the coaster should be sufficient to safely house the sensor and should typically be < 10mm. One reason for keeping the depth of the coaster to a minimum is that if the container is placed overlapping the edge of the coaster, the container will be tilted., If it is assumed that the container has a diameter of 80mm, the steepest angle at which the container will be tilted with respect to the surface of the coaster should be sin-1 (10/70) = 8.2°. Assuming that the contents is at least 10mm from the rim the chance of spillage is small, since this also depends upon the height of the container.

In this example of the invention the display 27 comprises 3 LEDs in Pulse Width Modulation configuration which will provide a user with a visual output which shows one of three states. Too Hot, Ideal or too cold. In this and other embodiments of the present invention, it will be necessary to estimate the transmission efficiency of the Infra-red radiation from source to final measurement. The difficulty in estimating transmission efficiency is that this varies over wavelength in addition as the target cools the incident wavelengths will lengthen so the values chosen are an average. Due to these losses a correction factor is provided to compensate for the losses through the system.

Figure 3 shows the stages in transmission from the heat source 33. Some transmission loss occurs because not all of the IR radiation is transmitted through the bottom surface of the container 35, and further losses occur at the transmission window 37. These transmission losses are illustrated in graphs 32, 34 which show frequency dependent transmission. The sensor response 39 is illustrated in graph 36 and final measurement 41 shows an overall loss of around 40% from initial heat source to final measurement.

In other embodiment of the invention, the sensor employs a Fresnel lens to focus the infra-red radiation onto the sensor. The distance from target to sensor is estimated at 4mm. The focal length of the Fresnel lens is estimated at 3mm. A power source is also provided. In this and other embodiments of the present invention several power options may be used as follows:

A rechargeable system using USB to provide the charge, but which can be unplugged for a period of time until recharging is required.

Induction coils, standard batteries or an external power source such as a +5V USB power from a desktop / laptop computer may be used.

Figure 4 shows a block diagram of a system architecture suitable for use in one or more embodiment of the present invention. A power source 47 powers a microcontroller 49 which receives data from a heat sensor 53 and display 51. The microcontroller 49 comprises a timer which provides a Pulse Width Modulated (PWM) output to dim and brighten the LEDs depending upon the heat detected. A Bluetooth low energy (BLE) module 48 is provided for transmitting information to a computing device.

A Serial Communications Interface provides communications between the heat sensor and the microcontroller.

A Universal Asynchronous Receiver Transmitter (UART) can provide asynchronous communications between the Coaster and a mobile application using BLE.

The heat sensor has an accuracy of ±3°C, with a range of 0°C to 60°C.

In the embodiment of figure 2A and 2B, the display option chosen is the three LEDs. The operation of these LEDs is described below with reference to figure 5. Assuming that initially there is no container on top of the Coaster, and further assuming that the container that is placed on top of the Coaster is too hot to begin with, there are five possible phases proposed for the display. Figure 5 shows the on/off control of a red, green and blue LED in graphs 67, 69 and 71 respectively. The change in LED response is shown at four time points T1 , T2, T3 and T4 73, 75, 77 and 79 respectively the phases described in the following table. No target detected 81 Measured temperature has not changed for a predefined period. All

LEDs are OFF

Hot Over-range 83 State Temperature change detected.

Red LED will flash to indicate over-range, assuming the contents of the container are hotter than the maximum measurable.

Green LED duty cycle = 0%

Blue LED duty c cle = 0%

Cooling A 85 State Target is cooling and is no longer over-ranging.

Red LED duty cycle reduces in proportion to temperature.

Green LED duty cycle increase in proportion to temperature.

Blue LED duty cycle = 0%

Cooling B 87 State The target has reached optimum temperature.

Red LED duty cycle = 0%

Green LED is flashing to indicate optimum temperature has been reached ±1°C. Thereafter, the green LED duty cycle decreases in proportion to the temperature.

Blue LED duty cycle = 0%. Thereafter begins to increase.

Cold 89 State The temperature of the target is 'cold'.

Red LED duty cycle = 0%

Green LED duty cycle = 0%.

Blue LED duty cycle = 100%

If the temperature change is < TBD°C for TBD seconds the blue LED flashes and then switches off.

Figure 6 is a flow diagram which describes the firmware used to implement wireless communication with an external device using a wireless communications standard for the purpose of displaying temperature information on an external device.

The device is initialised 103 then the temperature is calculated 105. If the temperature is less than 20°C 107, the device waits for 15s 109 and then switches off the display 111 because the device is deemed not to be in use. If the object temperature is greater than 75°C a signal goes to the over range display 115. If the temperature of the object reduces to 65°C 1 17, PWM ratios are calculated 119 to reflect the new temperature and the display is updated 121 . The term "kick the dog" is used to describe a process by which the software loop is reset if it does not operate in its normal way within a predetermined time limit. If it exceeds that time limit, it is assumed that there has been a malfunction and a reset is needed.

In examples of the invention where the temperature data is displayed externally, this data is sent to UART TX register 125 where it is sent to an external device such as a tablet computer or mobile phone. Each data packet begins with a magic number to identify the start of a packet. Magic Numbers from UART Receive interrupt 126

Figure 7A and 7B show a side view and a plan view respectively of a second

embodiment of a mat in accordance with the present invention. Both figures show a mat 131 which has a housing 133 in which is contained a sensor pack 135. Window or IR filter 139 is positioned on the top surface of the coaster 131 ; this being the surface onto which an object would be placed to detect its temperature. In addition indicator lights eight 27 are provided to show a measure of the detected temperature. The coaster is made from a suitable heat and water resistant material. It is known that the diameter of objects such as plates and dishes vary in size. In order to

accommodate containers of different sizes, a diameter of 300mm was chosen in this embodiment of the invention. The area of the mat upon which the container is to be placed is identified on the upper surface of the coaster because placement of the container correctly upon the coaster improves the accuracy of the measurement.

Figures 8A. and 8B show a side view and a plan view respectively of a third

embodiment of a coaster in accordance with the present invention wirelessly connected to an output device. Both figures show a mat 141 which has a housing 143 in which is contained a sensor pack 145. Window or IR filter 149 is positioned on the top surface of the coaster 141 ; this being the surface onto which an object would be placed to detect its temperature. In this example of the present invention, the signal which provides information on the temperature of the object is sent wirelessly to an external device 151 Fig. 8C using the Bluetooth ^® communications protocol. The signal is processed on the external device and the temperature information displayed in a suitable format.

The coaster is made from a suitable heat and water resistant material. It is known that the diameter of objects such as plates and dishes vary in size. In order to

accommodate containers of different sizes, a diameter of 300mm was chosen in this embodiment of the invention. The area of the mat upon which the container is to be placed is identified on the upper surface of the coaster because placement of the container correctly upon the coaster improves the accuracy of the measurement.

The present invention provides a safe and efficient apparatus for measuring the temperature of an object. The above embodiments of the invention are intended for use with cups containing a hot liquid such as tea or coffee and it is further envisaged that their use would be beneficial in catering establishments where hot drinks are sold and there is a risk of injury where a liquid has been heated above a suitable temperature. However, the patent application is not limited to such uses. Such a device may be incorporated into a tray and be used when distributing meals on hospital wards, care homes or the like. In such situations a person may be receiving assistance to feed themselves and the person assisting may not be able to determine whether the food is too hot or at a safe temperature. It may be particularly applicable when feeding those with dementia.

Plates used in hospitals or in other situations where large scale catering is used have covers to retain heat in the food and to allow the plates to be safely transported without contamination or spillage. In another embodiment, the present invention is incorporated in a lid for a plate, bowl or cup so that the pe son serving the food or assisting the eater is able to ensure that the eater is not burned by the food being too hot.

In another embodiment, the device of the present invention may be provided for use in a car cup holder as either a separate coaster which is sized to fit in the existing cup holder or integrated into the cup holder of a car when the car is manufactured. Drivers and passengers often buy takeaway hot drinks and determining whether they are cool enough to drink when in a car is difficult. In addition, the movement of a car is more likely to cause spillages. Other embodiments may be created for airline passenger seats, trains and so on.

In another embodiment of the present invention, a mat, coaster or cover is provided with an electromagnetic communications output capability such as Bluetooth®. A user may download a software application onto a mobile device, a laptop or tablet from a coffee shop where they have bought a hot drink and the coaster, mat or cover can communicate temperature information to the device.

Advantageously, the coffee shop can also provide advertisement information, offers and the like to the user. Assessing the beverage temperature being a compelling reason for the user to open a software application.

The software application operates as follows:-

1. A user enters a coffee shop and orders a hot drink.

2. The user places the hot drink in proximity with a device in accordance with the present invention. This may be by placing the drink container on a mat or coaster in accordance with the present invention or placing a cover or lid made in accordance with the present invention on top of the cup. 3. The user goes to their mobile phone and opens the temperature sensing software app.

4. The user ensures that the mobile phone has Bluetooth ® switched on.

5. The coaster, mat or cover sends a signal to the phone which contains information on the temperature of the beverage.

6. The beverage temperature information is displayed on a graphical user interface.

7. The graphical user interface displays additional information such as, product offers and advertisements.

The software application is configurable by the user to allow the user to select a preferred ideal temperature range and can alert the user when the beverage's temperature is outwith the range by being too hot or too cold. The alert may be visual or aural.

In another embodiment of the present invention, a mat in accordance with the present invention is purchased for use in an office. The software application operates as follows:-

1. The user makes a hot drink for themselves. 2. The user places the hot drink on a mat or coaster in accordance with the present invention.

3. The user goes to their mobile phone and opens the temperature sensing software app. 4. The user ensures that the mobile phone has its wireless communication e.g. Bluetooth ® switched on.

5. The user may personalise the mat by setting a unique name. Further, the temperature monitor points (too hot, just right, too cold) can be personalised for each user.

6. The mat sends a signal to the phone which contains information on the

temperature of the beverage.

7. The beverage temperature information is displayed on a graphical user interface.

8. The graphical user interface displays additional information such as, product offers and advertisements.

When used in an office, the user may use the mat and software application to alert the user when the drink is cooling down to a user defined threshold temperature. This feature is of use when the user is engaged in work activities where they have, ffor example left their hot drink at their desk. The present invention and software app will alert the user to this eventuality and allow the user to return to their drink before it is too cold.

Improvements and modifications may be incorporated herein without deviating from the scope of the invention.