Glove detection/adjustment of sensitivity for capacitive sensing button and slider elements

Abstract

An input device for a control system of a vehicle includes at least one capacitive-sensing button, an actuation detection electrical circuit, a proximity sensor, a proximity temperature sensor, and a processor. In use, the capacitive-sensing button receives an actuation from a user. The actuation alters a capacitance value of the button. The detection electrical circuit comprises a threshold value and it outputs a button actuation signal when the capacitance value exceeds the threshold value. The proximity sensor generates a proximity signal when an object is provided near the capacitive-sensing button. The proximity temperature sensor provides a temperature measurement of the nearby area. The processor adjusts the threshold value to an adjustment value that is derived from the comparison signal.

Claims

1. An input device for a control system of a vehicle, the input device comprising: at least one capacitive-sensing button, the at least one capacitive-sensing button being configured to receive an actuation from a user, wherein the actuation alters a capacitance value of the at least one capacitive-sensing button; an actuation detection electrical circuit having a threshold value, wherein the actuation detection electrical circuit outputs a button actuation signal when the sensed capacitance value exceeds the threshold value; a proximity sensor configured to generate a proximity signal when an object is in an area that is near the capacitive-sensing button; a proximity temperature sensor configured to provide a temperature measurement of the area that is near the capacitive-sensing button; and a processor, comprising: a comparison unit configured to receive the temperature measurement and the proximity signal, wherein the comparison unit generates a comparison signal that is derived from the temperature measurement and from the proximity signal, and an adjustment unit configured to adjust the threshold value to an adjustment value that is derived from the comparison signal, wherein an ambient temperature is derived by the processor from previous temperature measurements from the proximity temperature sensor, or from a second temperature sensor, over a predetermined period of time, wherein the comparison unit generates a pre-determined low sensitivity threshold comparison signal when the temperature measurement of the proximity temperature sensor exceeds the derived ambient temperature, and, based on the pre-determined low sensitivity threshold comparison signal, the adjustment unit changes the threshold value to a pre-determined low sensitivity threshold value, and wherein the comparison unit generates a pre-determined high sensitivity threshold comparison signal when the temperature measurement of the proximity temperature sensor is substantially the same as the derived ambient temperature, and, based on the pre-determined high sensitivity threshold comparison signal, the adjustment unit changes the threshold value to a pre-determined high sensitivity threshold value.

2. The input device according to claim 1, wherein the capacitive-sensing button is configured to provide the proximity sensor signal.

3. The input device according to claim 1, wherein the comparison unit has a module configured to generate the comparison signal based on a predetermined mathematical comparison function of the temperature measurement and of the proximity signal.

4. The input device according to claim 1, wherein the comparison unit has a module configured to generate the comparison signal that comprises a value selected from a set of pre-determined comparison values based on the temperature measurement and on the proximity signal.

5. The input device according to claim 1, wherein the adjustment unit has a module configured to determine the adjustment value based on a predetermined mathematical adjustment function of the comparison signal.

6. The input device according to claim 1, wherein the adjustment unit has a module configured to select the adjustment value from a set of pre-determined comparison values based on the comparison signal.

7. The input device according to claim 1, wherein the previous temperature measurements used to derive the ambient temperature are provided by the second temperature sensor.

8. The input device according to claim 1, wherein the previous temperature measurements used to derive the ambient temperature are provided by the proximity temperature sensor.

9. A control module of a vehicle comprising: an input device according to claim 1 configured to receive an actuation from a user and to output a button actuation signal; and a control unit having a set of predetermined system function selection signals, the control unit being configured to receive the button actuation signal from the input device and to provide a system function selection signal selected from the set of pre-determined system function selection signals, the selection being provided according to the button actuation signal.

10. The control module according to claim 9, wherein the control module is configured to provide a radio function selection signal to a radio of a vehicle.

11. The control module according to claim 9, wherein the control module is configured to provide an air conditioning selection signal to an air conditioning unit of a vehicle.

12. The control module according to claim 9, wherein the control module is configured to provide a navigation function selection signal to a navigation unit of a vehicle.

13. A method of operating an input device for a control system of a vehicle, the method comprising: generating a proximity signal when an object is provided in an area that is near a capacitive-sensing button; obtaining a temperature measurement in the area that is near the capacitive-sensing button when the proximity signal is generated; deriving an ambient temperature based upon previous temperature measurements in the area that is near the capacitive-sensing button; comparing the temperature measurement obtained at the obtaining step against the derived ambient temperature; selecting a button actuation threshold value from a set of pre-determined threshold values according to the comparison between the temperature measurement obtained at the obtaining step and the derived ambient temperature; and adjusting a threshold value of an actuation detection electrical circuit of the capacitive-sensing button according to the button actuation threshold value such that: a low sensitivity threshold value is set when the temperature obtained at the obtaining step exceeds the derived ambient temperature, and a pre-determined high sensitivity threshold is set when the temperature obtained at the obtaining step is substantially the same as the derived ambient temperature.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in detail below on the basis of an exemplary embodiment in conjunction with the drawings, in which:

(2) FIG. 1 illustrates an Integrated Center Stack (ICS) of a car;

(3) FIG. 2 is an input device of a car radio of the ICS of FIG. 1;

(4) FIG. 3 illustrates a driver being seated inside the car and being seated next to the ICS of FIG. 1;

(5) FIG. 4 illustrates a flow chart of operating the input device of the ICS of FIG. 2;

(6) FIG. 5 illustrates an implementation of a capacitive button of the input device of FIG. 2;

(7) FIG. 6 illustrates a temperature graph of the car radio of the ICS of FIG. 1;

(8) FIG. 7 illustrates a block diagram of an implementation of the input device of FIG. 2; and

(9) FIG. 8 illustrates a further block diagram of an implementation of the input device of FIG. 2.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

(10) In the following description, details are provided to describe embodiments of the application. It shall be apparent to one who is skilled in the art, however, that these embodiments may be practiced without such details.

(11) Some parts of the embodiments, which are shown in the figures, have similar parts. The similar parts may have the same names or similar part numbers. The description of one similar part also applies by reference to other similar parts, where appropriate, thereby reducing repetition, of text without limiting the disclosure.

(12) FIG. 1 shows a car 10, which includes an Integrated Center Stack (ICS) 12, which includes a car radio. The radio is not shown in FIG. 1. The ICS 12 comprises a face plate 14 with an external surface, a display panel 16, and a control console 17. The control console 17 is also called an input device. The display panel 16 and the control console 17 are placed on the external surface of the face plate 14.

(13) As seen in FIG. 2, the input device 17 comprises a plurality of capacitive-sensing buttons 19, an infra-red (IR) sensor 21, a proximity sensor 23, as well as a processor 26 together with an integrated memory module 27. The capacitive-sensing buttons 19 are also called capacitive touch buttons or capacitive buttons. The capacitive buttons 19, the IR sensor 21, the proximity sensor 23, and the integrated memory module 27 are electrically connected to the processor 26.

(14) The capacitive buttons 19, the IR sensor 21 and the proximity sensor 23 are placed on an external surface of the input device 17 of the ICS face plate 14.

(15) In a general use, the car 10 can be replaced by a commercial vehicle, like a truck or lorry.

(16) In use, the ICS 12 is installed in a central portion of the car 10 along its longitudinal axis. The ICS 12 is also placed between a driver and a front passenger of the car 10, as illustrated in FIG. 3. The car 10 is used for transporting passengers.

(17) The ICS 12 serves as a Human Machine Interface (HMI) for the radio of the car 10. The radio provides contents from a radio station for passengers of the car 10. The input device 17 receives inputs or actuations from a user to select a function of the radio. The received inputs are afterward sent to the processor 26. The display panel 16 shows the present status of the radio. In practice, the display panel 16 may also show status of other components of the car 10, such as Heating, Ventilation, and Air-Conditioning (HVAC) controllers and navigation devices.

(18) The IR sensor 21 has a viewing angle A, which is also called a temperature sensing angle. The IR sensor 21 is positioned such that the viewing angle A is directed towards a nearby object, which is placed in front of and near any one of the capacitive buttons 19 of the input device 17. The IR sensor 21 measures surface temperature of this nearby object. The surface temperature measurement is generated before the object touches the capacitive buttons 19. The measured temperature reading is afterward transmitted to the processor 26.

(19) Moreover, the IR sensor 21 is also used to measure ambient temperature inside the car 10. The IR sensor 21 obtains a plurality of temperature measurements at a certain interval over a certain period, as illustrated in FIG. 6, which shows a graph 55 of the surrounding temperature. These temperature measurements are then averaged to determine the ambient temperature. The measured ambient temperature reading is later transmitted to the processor 26.

(20) In a generic sense, another temperature sensor of the car, instead of the IR sensor 21, can also be used to determine the ambient temperature.

(21) The proximity sensor 23 is positioned such that it provides a proximity detection signal when an object is placed close to any one of the capacitive buttons 19 of the input device 17. The proximity detection signal is generated before the object touches the capacitive buttons 19. In short, the proximity detection signal is provided once the object is placed near one of the capacitive buttons 19. The generated proximity detection signal is then transmitted to the processor 26.

(22) The capacitive buttons 19 are used for receiving a touch from a user, wherein the user touch is used to indicate a button actuation. In effect, the touch changes a capacitance of the respective button 19. This capacitance change is then used by a detection chipset or the detection electric circuits of the capacitive buttons 19 to identify the button actuation. These detection electric circuits have a detection threshold, which is set such that a detection signal is generated when the capacitance change exceeds the detection threshold.

(23) If the detection threshold is low, then only a small capacitance change is needed to generate the detection signal. This means that the detection circuit has high detection sensitivity. On the other hand, if the detection threshold is high, then a large capacitance change is needed to generate the detection signal. In other words, the detection circuit has low detection sensitivity.

(24) The processor 26 receives the above-mentioned object surface temperature measurement from the IR sensor 21 and the object proximity detection signal from the proximity sensor 23.

(25) The processor 26 then adjusts the detection threshold of the detection electric circuits of the capacitive buttons 19 according the received object surface temperature measurement and the received object proximity detection signal. This allows the buttons 19 to adapt its button actuation sensitivity according to the different manner of actuation.

(26) If the processor 26 would adjust the button detection threshold higher, the buttons 19 would then have lower detection sensitivity. Put differently, a smaller capacitance change is required to actuate the buttons 19.

(27) On the other hand, if the processor 26 would adjust the button detection threshold lower, the buttons 19 would then have higher detection sensitivity. In other words, a smaller capacitance change is required to actuate the buttons 19. In cold weather, the users often wear gloves, which, because of their inherent property, often induce a smaller change of capacitance.

(28) These low and the high thresholds are selected such that the detection electrical circuits are not driven to saturation. In short, the thresholds are placed within operating range of detection electrical circuits.

(29) In application, a screen touch slider can comprise a plurality of capacitive buttons 19 that are arranged in a line next to each other. When one capacitive button 19 of the slider is actuated, the capacitive buttons 19 of the slider are disabled. Operationally, this screen touch slider acts as a mechanical slider.

(30) In a general sense, the embodiment can also include more than two levels of threshold sensitivities.

(31) This adaption of button detection threshold improves detection of button actuation. In short, it is able to provide a detection threshold that is suitable or appropriate for the type of actuation. This is unlike other input devices that provide buttons with a fixed button actuation threshold for different types of actuation. A button detection threshold that is suitable for button actuation using bare fingers is often not suitable for button actuation using fingers that are covered by a glove. Similarly, a button detection threshold that is suitable for button actuation using fingers that are covered by a glove is often not suitable for button actuation using bare fingers.

(32) FIG. 4 shows a flow chart 30 for a possible method of operating the capacitive buttons 19.

(33) The flow chart 30 includes a step 32 of the processor 26 checking or polling for a proximity detection signal from the proximity sensor 23. A presence of the proximity detection signal would indicate that an object is placed near one of the capacitive buttons 19.

(34) When the processor 26 receives the proximity detection signal, the processor 26 then obtains a measurement from the IR sensor 21 in a step 34 of the flow chart 30. This measurement serves to provide a surface temperature measurement of the nearby object. The processor 26 assumes that the object is a user hand, since often only the user would place his hand near the buttons 19 for actuating the buttons 19. The processor 26 uses the surface temperature measurement to indicate whether or not the user is wearing gloves.

(35) The processor 26 then adjusts the detection threshold according to the received surface temperature measurement and the received proximity detection signal, in a step 36 of the flow chart 30. If the received surface temperature measurement is higher than the ambient temperature, the processor 26 would assume that user is not wearing gloves, since human hands are normally warm relative to the ambient temperature. The processor 26 subsequently sets the capacitive sensitivity of the buttons 19 to high detection threshold. In other words, this enables the buttons to have low actuation sensitivity. On the hand, if the received surface temperature measurement is about the same as the ambient temperature, the processor 26 would assume that user is wearing gloves. This is because gloves often have the same surface temperature as the ambient temperature. The processor 26 later sets capacitive sensitivity of the buttons 19 to low detection threshold, wherein the buttons has high actuation sensitivity.

(36) The detection threshold of the buttons 19 are preferably set or changed before the buttons 19 are touched or actuated by the user.

(37) In this manner, the actuation sensitivity of the capacitive buttons 19 is improved since the actuation sensitivity is adapted according to the type of actuation.

(38) FIG. 5 shows an implementation of the capacitive button 19 being connected to an actuation detection electric circuit. FIG. 5 depicts a pair of terminals 40 and 42 being connected to a charged capacitor 45 and to an actuation detection electric circuit 47. The actuation detection electric circuit 47 comprises an actuation detection threshold.

(39) In particular, the terminal 40 is connected to the electrical ground while the terminal 42 is connected to one end of the capacitor 45 and to the actuation detection electric circuit 47. Another end of capacitor 45 is connected to the electrical ground.

(40) In use, the terminals 40 and 42 are intended for receiving an actuation, in the form of a touch, from a user, wherein the actuation acts to electrically connect the terminal 40 to the terminal 42. This connection also serves to alter the capacitance charge of the capacitor 45 by discharging the capacitance charge through the terminals 40 and 42 to the electrical ground.

(41) The actuation detection electric circuit 47 serves to monitor the capacitance charge of the capacitor 45. It also acts to generate an actuation signal when the altered capacitance charge of the capacitor 45 exceeds its actuation detection threshold.

(42) FIG. 7 shows a block diagram 60 of an implementation of the input device 17.

(43) The block diagram 60 shows a processor 26 connected to a proximity sensor 23, to an IR sensor 21, and to an actuation detection electric circuit 47, which is connected to a capacitive-sensing button 19. The processor 26 includes a comparison unit 60 and an adjustment unit 61. The adjustment unit 61 is connected to the comparison unit 60.

(44) In practice, the actuation detection electric circuit 47 and the proximity sensor 23 may have similar integrated circuits (ICs) or electrical circuits.

(45) In use, the comparison unit 60 is intended for receiving a temperature measurement from the IR sensor 21 and for receiving a proximity signal from the proximity sensor 23. The comparison unit 60 then generates a comparison signal to the adjustment unit 61. The comparison signal is determined from the temperature measurement and from the proximity signal using a mathematical function or selecting from a table of predetermined comparison signal values.

(46) The adjustment unit 61 is used for receiving the comparison signal from the comparison unit 60. The adjustment unit 61 later derives a threshold adjustment value from the comparison signal. The derivation can be achieved using a mathematical function or by selecting from a table of pre-determined threshold adjustment values. After this, the adjustment unit 61 changes a threshold value of the actuation detection electrical circuit 47 to the derived threshold adjustment value.

(47) In practice, the proximity sensor 23 can use the change of capacitive charge of the button 19 for sensing presence or proximity of the nearby object. Implementation of such practice is illustrated in the next figure.

(48) FIG. 8 shows a block diagram 160 of a further implementation of the input device 17. This block diagram 160 is adapted from the block diagram 60 of the FIG. 7. Hence, the block diagrams 60 and 160 have similar parts.

(49) The block diagram 160 replaces the capacitive buttons 19 of the block diagram 60 with integrated capacitive buttons 119. These integrated capacitive buttons 119 perform the functions of the capacitive buttons 19 and the functions of the proximity sensor 23. Hence, the proximity sensor 23 is removed from the block diagram 160.

(50) The geometrical shape of the parts the integrated capacitive buttons 119 is adapted according for this application.

(51) In use, these integrated capacitive buttons 119 use the change of capacitive charge of the button 119 to generate the proximity detection signal for detecting the presence or proximity of the nearby object.

(52) In a special embodiment, the IR sensor 21 is also used for measuring internal cabin temperature of the car 10, wherein the internal cabin temperature is transmitted to a Heating, Ventilation, and Air-Conditioning (HVAC) controller. The HVAC controller then adjusts ambient temperature of the cabin according the received internal cabin temperature. The temperature adjustment is achieved by adjusting blower speed, discharge temperature and/or air distribution of the air conditioner of the car 10.

(53) The embodiments can also be described with the following lists of features or elements being organized into items. The respective combinations of features, which are disclosed in the item list, are regarded as independent subject matter, respectively, that can also be combined with other features of the application.

(54) An input device for a control system of a vehicle, the input device comprising at least one capacitive-sensing button, the capacitive-sensing button being provided for receiving an actuation from a user, wherein the actuation alters a capacitance value of the capacitive-sensing button,

(55) an actuation detection electrical circuit comprising a threshold value, wherein the actuation detection electrical circuit outputs a button actuation signal when the capacitance value exceeds the threshold value,

(56) a proximity sensor for generating a proximity signal when an object is provided in an area that is near the capacitive-sensing button,

(57) a proximity temperature sensor for providing a temperature measurement of the area that is near the capacitive-sensing button, and

(58) a processor comprising a comparison unit for receiving the temperature measurement and the proximity signal, wherein the comparison unit generates a comparison signal that is derived from the temperature measurement and from the proximity signal, and an adjustment unit for adjusting the threshold value to an adjustment value that is derived from the comparison signal.

(59) The input device, wherein

(60) the capacitive-sensing button provides the proximity sensor signal.

(61) The input device, wherein

(62) the comparison unit comprises a module for generating the comparison signal based on a predetermined mathematical comparison function of the temperature measurement and of the proximity signal.

(63) The input device, wherein

(64) the comparison unit comprises a module for generating the comparison signal which comprises a value that is selected from a set of pre-determined comparison values based on the temperature measurement and on the proximity signal.

(65) The input device, wherein

(66) the adjustment unit comprises a module for determining the adjustment value based on a predetermined mathematical adjustment function of the comparison signal.

(67) The input device, wherein

(68) the adjustment unit comprises a module for selecting the adjustment value from a set of pre-determined comparison values based on the comparison signal.

(69) The input device, wherein

(70) the comparison unit generates a pre-determined low sensitivity threshold comparison signal when the temperature measurement exceeds a temperature measurement which corresponds to an ambient temperature.

(71) The input device, wherein

(72) the comparison unit generates a pre-determined high sensitivity threshold comparison signal when the temperature measurement is approximately the same as a temperature measurement which corresponds to an ambient temperature.

(73) The input device, wherein

(74) the temperature measurement, which corresponds to the ambient temperature, is provided by an temperature sensor.

(75) The input device, wherein

(76) the temperature measurement, which corresponds to the ambient temperature, is derived from the temperature measurement from the proximity temperature sensor over a predetermined period.

(77) A control module of a vehicle comprising:

(78) an input device according to one of the abovementioned items for receiving an actuation from a user and for outputting a button actuation signal, and

(79) a control unit that comprises a set of predetermined system function selection signals, the control unit being provided for receiving the button actuation signal from the input device and for providing a system function selection signal which is selected from the set of pre-determined system function selection signals, the selection being provided according to the button actuation signal.

(80) A radio module of a vehicle comprising:

(81) a control system for providing a radio function selection signal and a tuner module for receiving the radio function selection signal and for providing a radio function according to the radio function selection signal.

(82) An air conditioning module of a vehicle comprising:

(83) a control system for providing an air conditioning selection signal and an air conditioning unit for receiving the air conditioning selection signal and for providing an air conditioning function according to the air conditioning function selection signal.

(84) A navigation module of a vehicle comprising

(85) a control system for providing a navigation function selection signal and

(86) a navigation unit for receiving the navigation function selection signal and for providing a navigation function according to the navigation function selection signal.

(87) A method of operating an input device for a control system of a vehicle, the method comprising

(88) generating a proximity signal when an object is provided in an area that is near a capacitive-sensing button,

(89) obtaining a temperature measurement of the object when the proximity signal is generated,

(90) comparing the temperature measurement of the object against the ambient temperature,

(91) selecting a button actuation threshold value from a set of pre-determined threshold values according to the comparison between the temperature measurement of the object and the ambient temperature, and

(92) adjusting a threshold value of an actuation detection electrical circuit of the capacitive-sensing button according to the button actuation threshold value.

(93) Although the above description contains much specificity, this should not be construed as limiting the scope of the embodiments but merely providing illustration of the foreseeable embodiments. The above stated advantages of the embodiments should not be construed especially as limiting the scope of the embodiments but merely to explain possible achievements if the described embodiments are put into practice. Thus, the scope of the embodiments should be determined by the claims and their equivalents, rather than by the examples given.

REFERENCE NUMBERS

(94) 10 car 12 Integrated Center Stack (ICS) 14 face plate 16 display panel 17 input device 19 capacitive button 21 infra-red (IR) sensor 23 proximity sensor 26 processor 27 integrated memory module 30 flow chart 32 step 34 step 36 step 40 terminal 42 terminal 45 capacitor 47 actuation detection electric circuit 55 temperature graph 60 block diagram 119 integrated capacitive button 160 block diagram A viewing angle

(95) Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.