WO2024056271A1 - Trigger module, device, method for operating a trigger module and method for operating a device - Google Patents

Trigger module, device, method for operating a trigger module and method for operating a device Download PDF

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Publication number
WO2024056271A1
WO2024056271A1 PCT/EP2023/071520 EP2023071520W WO2024056271A1 WO 2024056271 A1 WO2024056271 A1 WO 2024056271A1 EP 2023071520 W EP2023071520 W EP 2023071520W WO 2024056271 A1 WO2024056271 A1 WO 2024056271A1
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WO
WIPO (PCT)
Prior art keywords
trigger module
laser
main system
analog
signal
Prior art date
Application number
PCT/EP2023/071520
Other languages
French (fr)
Inventor
Masoud BAHRAMI
Markus Dantler
Original Assignee
Ams International Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Ams International Ag filed Critical Ams International Ag
Publication of WO2024056271A1 publication Critical patent/WO2024056271A1/en

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/941—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated using an optical detector
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/04—Systems determining the presence of a target
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/491—Details of non-pulse systems
    • G01S7/4912—Receivers
    • G01S7/4916—Receivers using self-mixing in the laser cavity
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
    • H03K2217/94—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated
    • H03K2217/941—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated using an optical detector
    • H03K2217/94102—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated using an optical detector characterised by the type of activation
    • H03K2217/94108—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated using an optical detector characterised by the type of activation making use of reflection

Definitions

  • the present disclosure relates to a trigger module, a device comprising a trigger module, a method for operating a trigger module and to a method for operating a device.
  • US 7,227,464 B2 describes a wake-up method from sleep mode of an optical motion sensing device comprising a photodetector.
  • US 11,156,456 B2 describes an optical proximity sensor integrated into a camera module.
  • the sensors described in US 11,156,456 B2, US 2020/0374620 Al and WO 2021/045878 Al require multiple components, for example two or more diodes and a photodiode, and therefore are large and have a high complexity. As these sensors use power extensive blocks like multi-bit analog-to-digital converter, EFT and other calculation units (e.g. adders or peak detectors) they have a high energy consumption. Further, these sensors are sensitive to ambient light and therefore require an additional optical filtering.
  • a further object is to provide a device comprising a trigger module that can efficiently activate a main system.
  • Another obj ect is to provide a method for operating a trigger module that can ef ficiently activate a main system .
  • a further obj ect is to provide a method for operating a device wherein a main system can be ef ficiently activated with a trigger module .
  • the trigger module comprises a laser .
  • the trigger module can comprise exactly one laser .
  • the laser may comprise a cavity resonator .
  • the laser can be configured to emit electromagnetic radiation, especially coherent electromagnetic radiation, out of the trigger module .
  • the laser can be configured to emit radiation in a visible (VIS ) , infrared (IR) , nearinfrared (NIR) or ultraviolet (UV) spectral range .
  • the laser can be configured to emit all kinds of radiation with any wavelength .
  • the laser is configured to emit radiation in the near infrared portion of the electromagnetic spectrum .
  • the laser can be configured to emit radiation with a wavelength in a range between 700 nm and 1500 nm, between 800 nm and 1000 nm or between 900 nm and 980 nm .
  • the electromagnetic radiation emitted by the laser can be emitted to a sensing region .
  • the electromagnetic radiation emitted by the laser is focused into the sensing region .
  • the laser is the only laser comprised by the trigger module .
  • the laser can be configured to undergo self-mixing interference (SMI) .
  • SMI self-mixing interference
  • at least a fraction of the radiation emitted by the laser is reflected and/or backscattered from an object outside the trigger module.
  • the reflected and/or backscattered radiation can be re-injected into the cavity of the laser.
  • the self-mixing interference can cause a modulation in a junction voltage of the laser.
  • the object outside the trigger module causing the self-mixing interference can be a finger and/or a robot arm, for example.
  • the object moves in the sensing region.
  • the trigger module comprises a filter.
  • the filter can be configured to provide a junction voltage signal across the laser.
  • the junction voltage signal across the laser can provide or comprise the junction voltage across the laser.
  • the filter is configured to provide a differential voltage.
  • the filter can be configured to provide a junction voltage signal of the laser to subsequent components.
  • the filter can be configured to provide an analog junction voltage signal.
  • the analog junction voltage signal can provide or comprise the junction voltage across the laser.
  • the analog junction voltage signal can be modulated due to the self-mixing interference of the laser.
  • the modulated junction voltage signal comprises information of a self-mixing interference signal.
  • the self-mixing interference signal can, for example, contain information on the presence of an object within the sensing region, a distance of the object to the laser and/or a movement of the object.
  • the filter comprises a high pass filter and/or a low pass filter.
  • the filter is configured to provide a differential voltage.
  • the differential voltage can be obtained from the difference between the voltage on the input side and the voltage on the output side, for example.
  • the filter can be a DC blocking filter.
  • the trigger module comprises an analog-to-digital converter (ADC) .
  • ADC analog-to-digital converter
  • the ADC can be connected to the filter.
  • a signal of the filter is transmitted to the ADC.
  • the ADC can be connected to a frequency analyzer.
  • the ADC can be configured to convert the analog junction voltage signal provided by the filter into a digital junction voltage signal, this means a digital signal.
  • the ADC is a single-bit ADC.
  • the digital signal can, for example, take only two values, e.g. 0 and 1.
  • the ADC comprises a comparator with hysteresis, e.g. a Schmitt-trigger circuit.
  • the ADC can comprise and/or consist of a Schmitt-trigger.
  • the ADC can comprise a comparator.
  • the comparator can comprise one threshold.
  • the comparator can have two or more thresholds, for example.
  • the trigger module comprises a frequency analyzer.
  • the frequency analyzer can be connected to the ADC.
  • an output signal of the ADC is provided to the frequency analyzer.
  • the digital junction voltage signal is provided to the frequency analyzer .
  • the frequency analyzer can be configured to compare the frequencies of the digital j unction voltage signal to a predefined frequency range .
  • the predefined frequency range can be chosen depending on the system requirements and/or on the system setup .
  • the predefined frequency range depends on the movement of the obj ect to be detected .
  • the frequency range can be chosen such that the frequency analyzer can identi fy the movement to be detected .
  • the frequency analyzer can be configured to analyze a duration for which the digital j unction voltage signal is within the predefined frequency range .
  • a predefined minimum time can be set for the frequency analyzer .
  • the frequency analyzer can identi fy the digital j unction voltage signal as a valid signal . That the digital j unction voltage signal is identi fied as a valid signal can particularly mean that a particular movement of an obj ect in the sensing region is detected .
  • a predefined maximum time can be set for the frequency analyzer such that the digital j unction voltage signal is a valid signal i f the duration of the frequency within the predefined frequency range is smaller or equal to the maximum time .
  • the trigger module comprises an output .
  • a part of the trigger module for example the frequency analyzer, can be configured to provide a signal to the output .
  • the output can provide a signal to components connected with the trigger module .
  • the laser is configured to emit electromagnetic radiation to a sensing region outside of the trigger module .
  • the sensing region can be part of a device comprising the trigger module .
  • the sensing region can be arranged adj acent to the trigger module .
  • the sensing region comprises a sensing surface .
  • the device and/or the trigger module can comprise the sensing surface .
  • the sensing surface forms an outer surface of the trigger module and/or the device .
  • the electromagnetic radiation emitted by the laser is focused to the sensing surface .
  • the electromagnetic radiation emitted by the laser comprised by the trigger module can be emitted to the sensing region outside of the trigger module .
  • the electromagnetic radiation emitted by the laser is focused into the sensing region .
  • the sensing region provides an easily accessible region for the positioning and/or movement of the obj ect .
  • the trigger module comprises a laser, a filter, an ADC, a frequency analyzer, and an output , wherein the laser is configured to emit electromagnetic radiation to a sensing region outside of the trigger module , the filter is configured to provide an analog j unction voltage signal measured across the laser, the ADC is configured to convert the analog junction voltage signal into a digital junction voltage signal, the ADC is connected with the frequency analyzer and the frequency analyzer is connected with the output.
  • the trigger module can be configured to detect an object and/or a movement of an object within the sensing region.
  • electromagnetic radiation emitted by the laser is at least partially reflected back into the cavity resonator of the laser by the object, for example.
  • This causes a modulation of the junction voltage of the laser.
  • the obtained modulation of the analog junction voltage signal is converted into a digital junction voltage signal.
  • the digital junction voltage signal for example the frequencies of the digital junction voltage signal, can be compared to a predefined frequency by the frequency analyzer.
  • the trigger module can be active or inactive. This can mean that the trigger module can be either in an active state or in an inactive state. For example, the trigger module consumes more power when active than when inactive. That the trigger module is inactive can mean, that the trigger module is in a standby mode and/or in a sleep mode.
  • the trigger module has, amongst others, the advantage that it can be operated energy-efficient.
  • the trigger module only comprises components with a low power consumption, for example, only one laser and an ADC with a low power consumption, e.g. a Schmitt-trigger .
  • a further advantage of the trigger module described herein is that due to the self-mixing interferometry of the laser used to detect an object, no further components and/or detectors, e.g. photodiodes are necessary. Thus, the energy consumption of the trigger module is further reduced.
  • a trigger module with a low power consumption leads to an increased battery life time, which is, for example, critical for ultra-mobile and/or wearable devices.
  • the trigger module can be produced at low cost and formed compactly.
  • the trigger module is free of a photodiode. This means, the trigger module does not comprise any photodiode.
  • the trigger module is configured to provide an output signal provided by the frequency analyzer at its output. If the frequency analyzer detects a valid signal in the digital junction voltage signal, the frequency analyzer provides an output signal to the output of the trigger module.
  • the output can be connected with a main system of a device, the main system being different from the trigger module and the device comprising the trigger module.
  • the signal provided at the output of the trigger module can be transmitted to the main system of the device.
  • the signal provided at the output of the trigger module can be used to activate the main system, for example. In other words, the trigger module can be used as a wake-up trigger for the main system.
  • the trigger module can provide a signal at the output which can be provided to a main system.
  • the ADC comprises a single-bit analog-to-digital converter, especially a Schmitt- trigger.
  • the single-bit analog-to-digital converter can consume less electric energy than a multi-bit analog-to- digital converter.
  • the Schmitt-trigger can be configured to convert the analog junction voltage signal into a digital junction voltage signal.
  • the Schmitt-trigger comprises a predefined first threshold and a predefined second threshold.
  • the Schmitt-trigger returns a first value, e.g. 1. This value is maintained until the value of the digital junction voltage signal decreases below a second threshold.
  • the Schmitt-trigger returns a second value, e.g. 0, until the value of the digital junction voltage signal increases above the first threshold.
  • the power consumed by the trigger module can be decreased .
  • a further advantage of this embodiment is, that a Schmitt- trigger can be used to filter noise in the provided signal with an amplitude outside a range between the first threshold and the second threshold of the Schmitt-trigger.
  • the trigger module comprises an amplifier, wherein the amplifier is arranged between the laser and the ADC along a connection.
  • the amplifier can comprise a single-stage amplifier and/or a multi-stage amplifier. This means, the amplifier can have one or more stages.
  • the amplifier can be arranged between the filter and the ADC along a connection.
  • junction voltage signal provided by the filter can be processed, e.g. amplified, to be easier processable by the ADC, for example by the Schmitt-trigger .
  • the laser comprises a vertical-cavity surface-emitting laser diode (VCSEL) .
  • VCSEL vertical-cavity surface-emitting laser diode
  • the trigger module comprises a driver, wherein the driver is configured to provide a direct current to the laser.
  • the laser can be operated with a direct current.
  • the driver can be configured to provide a constant current to the laser .
  • the trigger module can comprise a finite state machine, wherein the finite state machine is configured to activate at least some parts of the trigger module.
  • the finite state machine can be configured to activate some parts of the trigger module.
  • the finite state machine can be configured to activate all parts of the trigger module.
  • the finite state machine can be configured to activate at least the laser, the filter, the ADC and the frequency analyzer.
  • the finite state machine is configured as a switch. Due to the finite state machine , the parts of the trigger module can be easily activated .
  • the trigger module comprises an optical element , wherein the optical element is arranged between the laser and the sensing region .
  • the optical element can comprise a beam shaping element .
  • the optical element can be configured to shape the electromagnetic radiation emitted by the laser .
  • the optical element comprises a focusing element .
  • electromagnetic radiation can be easily focused to the sensing region and/or the sensing surface .
  • the device preferably comprises a trigger module described herein . This means all features disclosed for the trigger module are also disclosed for the device and vice-versa .
  • the device comprises a trigger module and a periodic signal generator, wherein the periodic signal generator is configured to provide a periodic signal to the trigger module .
  • the periodic signal generator can be connected with the trigger module .
  • the periodic signal generator can be configured to provide a periodic signal to the trigger module .
  • the periodic signal can be configured to activate the trigger module .
  • the trigger module can be configured to provide a pause signal to the periodic signal generator which can pause the operation of the periodic signal generator .
  • the operation of the periodic signal generator can be paused during the operation of the trigger module .
  • the pause signal can be generated and provided to the periodic signal generator by the finite state machine , for example .
  • the periodic signal generator comprises an oscillator and a timer .
  • the oscillator can be configured to generate an oscillating signal .
  • the oscillating signal comprises a low frequency .
  • the timer can be configured to allow only the transmittance of one pulse of the oscillating signal within a predetermined interval .
  • the periodic signal can, for example , comprise a pulse within a predetermined interval .
  • the oscillator and/or the periodic signal generator operate energy-ef ficient .
  • the device comprises a main system, wherein the trigger module is configured as a wake-up trigger for activating the main system, the main system is coupled to the output of the trigger module and the main system consumes more power when active than when inactive . Additionally or alternatively, the main system consumes more power during operation than the trigger module and/or the periodic signal generator consume during operation .
  • the trigger module can be integrated with the main system or the main system can be a separate component and be connected with the main system .
  • the low power consuming trigger module can be used to activate the high power consuming main system only when the main system is needed, the device can be operated energyef ficient .
  • the device comprises a sensing surface , wherein the sensing surface forms an outer surface of the device and the sensing surface adj oins the sensing region .
  • the sensing surface can be translucent and/or transparent for the electromagnetic radiation emitted by the laser .
  • the sensing surface can be translucent and/or transparent or non-transparent and/or non-translucent for electromagnetic radiation with a wavelength di f ferent from the wavelength of the electromagnetic radiation emitted by the laser .
  • the sensing surface forms an outer surface of the trigger module and/or of the main system .
  • the sensing surface can be a part of a cover covering the trigger module and/or the main system .
  • the sensing surface can be arranged on the side of the cover facing away from the laser .
  • the sensing surface can be configured as a touch surface .
  • the sensing surface is configured to be touched by an obj ect , for example a finger and/or a robot arm, which taps the sensing surface and/or swipes on the sensing surface .
  • the obj ect can thereby be at least temporarily in direct contact with the sensing surface .
  • the trigger module can be touch-sensitive . In this case , the electromagnetic radiation emitted by the laser can be focused to the sensing surface .
  • the focus point of the electromagnetic radiation emitted by the laser can be positioned in the sensing region spaced apart from the sensing surface .
  • the focus point can be at least 1 mm, for example at least 5mm or at least 1 cm away from the sensing surface .
  • the sensing surface can adj oin the sensing region .
  • the sensing surface directly adj oins the sensing region .
  • the sensing surface is arranged between the laser and the sensing region .
  • the sensing surface can comprise the sensing region .
  • the sensing surface provides an easily usable touch surface , to ensure an ef ficient recognition of the movement of the ob j ect .
  • the sensing surface is translucent for the electromagnetic radiation emitted by the laser .
  • the sensing surface is translucent and/or transparent for the electromagnetic radiation emitted by the laser .
  • the sensing surface can be translucent for ambient light .
  • the ambient light can be not coherent with the electromagnetic radiation emitted by the laser .
  • the electromagnetic radiation emitted by the laser can be at least partially transmitted through the sensing surface .
  • the ambient light is not coherent with the electromagnetic radiation emitted by the laser, the sel f-mixing interference signal is not influenced by the ambient light .
  • a transmission coef ficient of the sensing surface is higher for electromagnetic radiation emitted by the laser than for electromagnetic radiation of other wavelengths .
  • the source for the electromagnetic radiation of other wavelengths can be ambient light , for example .
  • An advantage of the device according to this embodiment is that the device is not sensitive to ambient light . Therefore , the trigger module can correctly identi fy the obj ect , e . g . the finger, and therefore , the main system can be activated ef ficiently and the device can be operated ef ficiently .
  • the device can also be ef ficiently operated in a bright or in a dark environment .
  • a method for operating a trigger module is provided .
  • the trigger module described herein can preferably be operated according to the method for operating a trigger module . This means all features disclosed for the trigger module are also disclosed for the method for operating a trigger module and vice-versa .
  • the method of operating a trigger module comprises the following steps :
  • the trigger module is a trigger module described herein .
  • An underlying consideration of the method described herein is to provide a method according to which an energy-ef ficient trigger module can be operated ef ficiently .
  • the frequency analyzer provides an output signal to the output i f the digital j unction voltage signal is within the predefined frequency range for a predefined time .
  • the predefined frequency range and/or the predefined time can, for example , be chosen according to the requirements , e . g . the setup and/or the movement to be detected . That the digital j unction voltage signal is within the predefined frequency range for the predefined time can mean, that the digital j unction voltage signal is a valid signal . In other words , the digital j unction voltage signal is within the predefined frequency range for the predefined time in case the obj ect performs the movement to be detected .
  • the frequency analyzer can be connected with the output and can be configured to provide an output signal to the output . This output signal can be used as a wakeup signal for components connected with the trigger module , for example .
  • the trigger module can return a signal depending on the external input and provide the signal to subsequent components .
  • the laser undergoes sel f-mixing interferometry caused by reflections and/or backscattering of the radiation emitted by the laser on an obj ect in the sensing region back into the laser .
  • the sel f-mixing interferometry signal can, for example , be obtained by detecting the modulation of the j unction voltage measured across the laser .
  • An advantage of using sel f-mixing interferometry as a detection method for the positioning and/or movement of an obj ect is that this method can be used in a plurality of environments , for example in a dark or in a bright environment .
  • the method does not require further components , like photodiodes , for example .
  • the energy consumption is reduced .
  • a method for operating a device is provided .
  • the device described herein can preferably be operated by the method for operating a device .
  • This means all features disclosed for the device are also disclosed for the method for operating a device and vice-versa .
  • the method for operating a device comprises the following steps :
  • - providing a trigger module , a main system and a sensing region, wherein the main system is inactive and the trigger module is active ,
  • the trigger module is activated by a signal provided by a periodic signal generator .
  • the periodic signal generator can be configured to provide a periodic signal to the trigger module .
  • the periodic signal generator can be connected with the trigger module .
  • the periodic signal generator can be configured to provide a periodic signal to the trigger module .
  • the periodic signal can be configured to activate the trigger module .
  • the main system is connected with the periodic signal generator and after deactivation of the main system, the periodic signal generator is activated .
  • the periodic signal generator is only active when the main system is inactive .
  • the periodic signal generator can provide a signal to the trigger module to activate the trigger module only in case the periodic signal generator is active .
  • the main system can provide an activation signal to the periodic signal generator to activate the periodic signal generator when the main system is inactive and/or directly before deactivation of the main system . That the main system is inactive can mean that the main system is in sleep mode . In other words , inactive can also mean that the main system is in standby mode and/or in an energy saving mode .
  • the main system can consume less power when inactive than when active .
  • the energy consumption of the device can be further reduced and the device can be operated energy-ef f iciently .
  • Figure 1 shows an embodiment of a device .
  • Figure 2 shows a signal generated by the periodic signal generator according to an embodiment .
  • Figure 3 shows a flowchart of the operation of the periodic signal generator according to an embodiment .
  • Figure 4 shows di f ferent scenarios of operation of the trigger module .
  • Figure 5 shows a flowchart of the operation of the trigger module according to an embodiment .
  • Figures 6 and 9 show analog j unction voltage signals according to embodiments .
  • Figures 7 , 8 and 10 show digital j unction voltage signals generated by an ADC according to embodiments .
  • Figure 11 shows a trigger module according to an embodiment .
  • Figure 1 shows a device 100 according to an embodiment .
  • the device 100 comprises a periodic signal generator 1 , a trigger module 2 , and a main system 3 . Further, the device 100 can comprise a sensing surface 4 and/or a sensing region 5 .
  • the sensing surface 4 forms an outer surface of the device 100 .
  • the sensing surface 4 can adj oin the sensing region 5 .
  • the periodic signal generator 1 is configured to provide a periodic signal 12 to the trigger module 2 .
  • the trigger module 2 can be configured to provide a pause signal 14 to the periodic signal generator 1 which can pause the operation of the periodic signal generator 1 .
  • the periodic signal generator 1 comprises an oscillator 10 and a timer 11 .
  • the oscillator 10 is configured to provide an oscillating signal .
  • the timer 11 can be configured to allow only the transmittance of one pulse 15 of the oscillating signal within a predetermined interval .
  • the trigger module 2 comprises a laser 22 , a filter 26 , an ADC 28 , a frequency analyzer 29 and an output 31 .
  • the laser 22 can be configured to emit electromagnetic radiation 24 to a sensing region 5 outside of the trigger module 2 and/or to a sensing surface 4 .
  • the laser 22 can comprise a verticalcavity surface-emitting laser diode .
  • the laser 22 can be configured to undergo sel f-mixing interferometry caused by reflections and/or backscattering of the electromagnetic radiation 24 emitted by the laser 22 on an obj ect 6 in the sensing region 5 and/or on the sensing surface 4 back into the laser 22 .
  • the filter 26 can be configured to provide an analog j unction voltage signal measured across the laser 22 .
  • the ADC 28 can be configured to convert the analog j unction voltage signal into a digital j unction voltage signal .
  • the ADC 28 can comprise a single-bit analog-to-digital converter .
  • the ADC 28 comprises a Schmitt-trigger .
  • the ADC 28 is connected with the frequency analyzer 29 .
  • the frequency analyzer 29 can be configured to compare the digital j unction voltage signal to a predefined frequency range and to a predefined time .
  • the frequency analyzer 29 is connected with the output 31 .
  • the trigger module 2 can be configured to provide an output signal 30 provided by the frequency analyzer 29 at its output 31 .
  • the frequency analyzer 29 provides an output signal 30 to the output 31 of the trigger module 2 i f the digital j unction voltage signal is within the predefined frequency range for the predefined time .
  • the trigger module 2 comprises an ampli bomb 27 .
  • the filter 26 and the ampli fier 27 are arranged between the laser 22 and the ADC 28 along a connection .
  • the trigger module 2 further comprises a driver 21 .
  • the driver 21 can be configured to provide a direct current , for example a constant current , to the laser 22 .
  • the trigger module 2 comprises a finite state machine 20 .
  • the finite state machine 20 can be configured to activate at least some parts of the trigger module 2 .
  • the finite state machine 20 can be configured to activate all parts of the trigger module 2 .
  • the expression "all parts" can, in particular, refer to the driver 21 , the laser 22 , the filter 26 , the ampli bomb 27 , the ADC 28 and to the frequency analyzer 29 .
  • the finite state machine 20 can, for example , be configured as a switch .
  • the trigger module 2 also comprises an optical element 23 .
  • the optical element 23 is arranged between the laser 22 and the sensing surface 4 and/or the sensing region 5 .
  • the sensing surface 4 is translucent for the electromagnetic radiation 24 emitted by the laser 22 .
  • the sensing surface 4 can comprise a transmission coef ficient .
  • the transmission coef ficient of the sensing surface 4 can be higher for electromagnetic radiation 24 emitted by the laser 22 than for electromagnetic radiation of other wavelengths .
  • the trigger module 2 can be configured as a wake-up trigger for activating the main system 3 .
  • the main system 3 is coupled to the output 31 of the trigger module 2 .
  • the main system 3 can consume more power when active than when inactive .
  • the main system 3 can provide an activation signal 13 to the periodic signal generator 1 to activate the periodic signal generator 1 .
  • Figure 2 shows a signal generated by the periodic signal generator 1 according to an embodiment .
  • the signal can comprise pulses 15 that occur repeatedly .
  • one pulse 15 occurs at certain intervals .
  • the interval can have a certain length Tl .
  • the signal comprises one pulse 15 .
  • the signal length Tl and/or the interval between two temporally adj acent pulses can be set by the timer 11 .
  • Figure 3 shows a flowchart of the method of operation of the periodic signal generator 1 according to an embodiment .
  • the periodic signal generator 1 checks i f the main system 3 is inactive . That the main system 3 is inactive can particularly mean that the main system 3 is in sleep mode . While the main system 3 is active ( indicated with path N) , no further steps of the periodic signal generator 1 are executed .
  • the periodic signal generator 1 When the main system 3 is inactive ( indicated with path Y) , in a step S2 , the periodic signal generator 1 generates the periodic signal 12 .
  • the periodic signal 12 is provided to the trigger module 2 .
  • the signal is provided to the finite state machine 20 of the trigger module 2 .
  • the finite state machine 20 can be configured to activate at least some parts of the trigger module 2 .
  • the trigger module 2 can provide the pause signal 14 to the periodic signal generator 1 .
  • the periodic signal generator 1 checks i f the pause signal 14 is received .
  • the periodic signal generator 1 generates the periodic signal 12 as long as the trigger module 2 does not provide the pause signal 14 (path N) .
  • the trigger module 2 provides the pause signal 14 to the periodic signal generator 1 (path Y) .
  • the periodic signal generator 1 is paused as long as the pause signal 14 is received .
  • the trigger module 2 can stop to provide the pause signal 14 to the periodic signal generator 1 .
  • the periodic signal generator 1 is paused until a reactivation signal is received from the trigger module 2 and/or until the activation signal 13 is received from the main system 3 .
  • step S5 the timer is reset and the periodic signal generator 1 continues with step S I .
  • Figure 4 shows di f ferent scenarios of operation of the trigger module .
  • the line LI indicates the enable-pulse 15 in the periodic signal provided to the trigger module 2 by the periodic signal generator 1 .
  • the trigger module 2 is in standby mode Ml .
  • the enable-pulse 15 is provided to the trigger module 2 .
  • the trigger module 2 is activated .
  • no obj ect moves in the sensing region 5 . Therefore , in a mode M2 , no modulated j unction voltage signal and/or no frequency is detected by the trigger module 2 .
  • the trigger module 2 then switches back to the standby mode Ml .
  • the trigger module 2 is in the standby mode Ml .
  • the enable-pulse 15 is provided to the trigger module 2 .
  • the finite state machine 20 of the trigger module 2 is configured to activate at least some parts of the trigger module 2 after receiving the enablepulse 15.
  • the finite state machine 20 can particularly activate all parts of the trigger module 2.
  • a mode M3 of the trigger module 2 a modulation in the junction voltage signal /frequency is detected.
  • a mode M4 it is determined that the detected frequency is not a valid signal. This can be determined by the frequency analyzer 29. For example, the detected frequency is not within the predefined frequency range. Alternatively or additionally, the time of the signal with the detected frequency does not last for the predefined time.
  • the trigger module switches to the standby mode Ml .
  • the trigger module 2 can remain in the standby mode Ml until an enable-pulse 15 from the periodic signal generator 1 is received.
  • the third scenario, L4 differs from the second scenario L3, in that in the third scenario L4 the trigger module 2 detects a valid signal, M5. Then, in mode M6, the trigger module 2 generates an output signal 30, which can be provided to a main system 3 at the output 31 of the trigger module 2. In mode M7 the timer 11 is paused.
  • FIG. 5 shows a flowchart of the operation of the trigger module 2 according to an exemplary embodiment.
  • the trigger module 2 is in standby mode. This means, the trigger module 2 is inactive, consuming less power than when the trigger module 2 is active.
  • the trigger module 2 checks, if the periodic signal 12 is received.
  • the periodic signal 12 can be provided to the trigger module 2 by the periodic signal generator 1. This step is repeated until a periodic signal 12 is received (path N) .
  • I f a periodic signal 12 is received (path Y) in a subsequent step S22 , at least some parts of the trigger module 2 are activated .
  • all parts of the trigger module 2 are activated .
  • the parts of the trigger module 2 can be activated by the finite state machine 20 , for example .
  • a next step S23 the trigger module 2 checks whether a modulated signal is available . I f no modulation on the j unction voltage across the laser is detected, the trigger module 2 returns to the start configuration shown in step S20 (path N) .
  • the frequency analyzer 29 compares the digital j unction voltage signal to a predefined frequency and to a predefined time .
  • I f no frequency of the digital j unction voltage signal , the converted sel f-mixing interferometry signal is within the predefined frequency range or a frequency is not within the predefined frequency range for the predefined time , the trigger module 2 returns to the start configuration S20 .
  • the frequency analyzer 2 identi fies the signal as a valid signal (path Y) .
  • step S26 an output signal 31 is provided to the main system 3 .
  • step S27 the trigger module provides a pause signal 14 to the periodic signal generator 1 to pause the timer 11 .
  • step S28 the timer 11 is reactivated by the trigger module
  • step S29, and the trigger module 2 returns to the start configuration S20.
  • Figure 6 shows a modulation on the analog junction voltage signal according to an exemplary embodiment.
  • the signal can, for example, be received for an object 6 swiping on the sensing surface 4.
  • the time is displayed in seconds (s) and on the y-axis the voltage is shown in volt (V) .
  • Figure 7 shows a digital junction voltage signal generated by an ADC 28 according to an exemplary embodiment.
  • the digital junction voltage signal is generated by the conversion of the analog junction voltage signal depicted in figure 6 by a Schmitt-trigger .
  • the digital junction voltage signal shown in figure 7 can be provided to the frequency analyzer 29.
  • the time is displayed in seconds (s) and on the y-axis the possible values of the ADC 28 are shown .
  • Figure 8 shows a digital junction voltage signal generated by an ADC 28 according to an exemplary embodiment.
  • the digital junction voltage signal shown here can alternatively be generated by a comparator.
  • the signal shown in figure 8 is a zoom-in of the digital junction voltage signal shown in figure 7.
  • the digital junction voltage signal comprises different frequencies.
  • the signal can be identified as a valid signal by the frequency analyzer 29 if one frequency or at least one of the frequencies is within the predefined frequency range for the predefined time.
  • On the y- axis the possible values of the ADC 28 are shown.
  • Figure 9 shows a modulation on the analog junction voltage signal according to an exemplary embodiment.
  • the signal can, for example, be received for an object 6 tapping on the sensing surface 4.
  • the time is displayed in seconds (s) and on the y-axis the voltage is shown in volt (V) .
  • Figure 10 shows a digital junction voltage signal generated by an ADC 28 according to an exemplary embodiment.
  • the digital junction voltage signal is generated by the conversion of the analog junction voltage signal depicted in figure 9 by a Schmitt-trigger .
  • the time is displayed in seconds (s) and on the y-axis the possible values of the ADC 28 are shown.
  • FIG 11 shows a trigger module 2 according to an embodiment.
  • the trigger module 2 comprises a driver 21, a laser 22, a filter 26, an amplifier 27, an ADC 28 and a frequency analyzer 29.
  • the filter 26 comprises a resistor 26a and two capacitors 26b.
  • the amplifier 27 is connected to the laser 22 in parallel. On each connection from the laser 22 to the amplifier 27 one capacitor 26b is arranged.
  • the resistor 26a is arranged along a connection between the driver 21 and the laser 22.
  • the filter 26 can be a high pass filter and/or a DC blocking filter, for example.
  • the ADC 28 can be a Schmitt-trigger .
  • ADC analog-to-digital converter

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Abstract

A trigger module is provided, comprising a laser, a filter, an analog-to-digital converter, a frequency analyzer and an output. The laser is configured to emit electromagnetic radiation to a sensing region outside of the trigger module. The filter is configured to provide an analog junction voltage signal measured across the laser. The analog-to-digital converter is configured to convert an analog junction voltage signal into a digital junction voltage signal. The analog-to digital converter is connected with the frequency analyzer and the frequency analyzer is connected with the output. Furthermore, a device comprising a trigger module, a method for operating a trigger module and a method for operating a device are provided.

Description

Description
TRIGGER MODULE, DEVICE, METHOD FOR OPERATING A TRIGGER MODULE AND METHOD FOR OPERATING A DEVICE
The present disclosure relates to a trigger module, a device comprising a trigger module, a method for operating a trigger module and to a method for operating a device.
US 7,227,464 B2 describes a wake-up method from sleep mode of an optical motion sensing device comprising a photodetector.
US 11,156,456 B2 describes an optical proximity sensor integrated into a camera module.
US 2020/0374620 Al and WO 2021/045878 Al describe self-mixing interference based sensors.
The sensors described in US 11,156,456 B2, US 2020/0374620 Al and WO 2021/045878 Al require multiple components, for example two or more diodes and a photodiode, and therefore are large and have a high complexity. As these sensors use power extensive blocks like multi-bit analog-to-digital converter, EFT and other calculation units (e.g. adders or peak detectors) they have a high energy consumption. Further, these sensors are sensitive to ambient light and therefore require an additional optical filtering.
It is an object to provide a trigger module that can efficiently activate a main system.
A further object is to provide a device comprising a trigger module that can efficiently activate a main system. Another obj ect is to provide a method for operating a trigger module that can ef ficiently activate a main system .
A further obj ect is to provide a method for operating a device wherein a main system can be ef ficiently activated with a trigger module .
According to at least one embodiment , the trigger module comprises a laser . The trigger module can comprise exactly one laser . The laser may comprise a cavity resonator . The laser can be configured to emit electromagnetic radiation, especially coherent electromagnetic radiation, out of the trigger module . For example , the laser can be configured to emit radiation in a visible (VIS ) , infrared ( IR) , nearinfrared (NIR) or ultraviolet (UV) spectral range .
Alternatively or additionally, the laser can be configured to emit all kinds of radiation with any wavelength . Preferably, the laser is configured to emit radiation in the near infrared portion of the electromagnetic spectrum . In particular, the laser can be configured to emit radiation with a wavelength in a range between 700 nm and 1500 nm, between 800 nm and 1000 nm or between 900 nm and 980 nm .
The electromagnetic radiation emitted by the laser can be emitted to a sensing region . Preferably, the electromagnetic radiation emitted by the laser is focused into the sensing region .
For example , the laser is the only laser comprised by the trigger module . The laser can be configured to undergo self-mixing interference (SMI) . For example, at least a fraction of the radiation emitted by the laser is reflected and/or backscattered from an object outside the trigger module. The reflected and/or backscattered radiation can be re-injected into the cavity of the laser. The self-mixing interference can cause a modulation in a junction voltage of the laser.
The object outside the trigger module causing the self-mixing interference can be a finger and/or a robot arm, for example. Preferably, the object moves in the sensing region.
According to at least one embodiment, the trigger module comprises a filter. The filter can be configured to provide a junction voltage signal across the laser. The junction voltage signal across the laser can provide or comprise the junction voltage across the laser. For example, the filter is configured to provide a differential voltage. Further, the filter can be configured to provide a junction voltage signal of the laser to subsequent components. For example, the filter can be configured to provide an analog junction voltage signal. The analog junction voltage signal can provide or comprise the junction voltage across the laser.
In case the laser undergoes self-mixing interference, the analog junction voltage signal can be modulated due to the self-mixing interference of the laser. For example, the modulated junction voltage signal comprises information of a self-mixing interference signal. The self-mixing interference signal can, for example, contain information on the presence of an object within the sensing region, a distance of the object to the laser and/or a movement of the object. For example, the filter comprises a high pass filter and/or a low pass filter. For example, the filter is configured to provide a differential voltage. The differential voltage can be obtained from the difference between the voltage on the input side and the voltage on the output side, for example. The filter can be a DC blocking filter.
According to at least one embodiment, the trigger module comprises an analog-to-digital converter (ADC) . The ADC can be connected to the filter. For example, a signal of the filter is transmitted to the ADC. Alternatively and/or additionally, the ADC can be connected to a frequency analyzer. The ADC can be configured to convert the analog junction voltage signal provided by the filter into a digital junction voltage signal, this means a digital signal. For example, the ADC is a single-bit ADC. In other words, the digital signal can, for example, take only two values, e.g. 0 and 1. Preferably, the ADC comprises a comparator with hysteresis, e.g. a Schmitt-trigger circuit. The ADC can comprise and/or consist of a Schmitt-trigger.
Alternatively or additionally, the ADC can comprise a comparator. The comparator can comprise one threshold. Alternatively, the comparator can have two or more thresholds, for example.
According to at least one embodiment, the trigger module comprises a frequency analyzer. The frequency analyzer can be connected to the ADC. Preferably, an output signal of the ADC is provided to the frequency analyzer. For example, the digital junction voltage signal is provided to the frequency analyzer . The frequency analyzer can be configured to compare the frequencies of the digital j unction voltage signal to a predefined frequency range .
The predefined frequency range can be chosen depending on the system requirements and/or on the system setup . For example , the predefined frequency range depends on the movement of the obj ect to be detected . In other words , the frequency range can be chosen such that the frequency analyzer can identi fy the movement to be detected .
Additionally, the frequency analyzer can be configured to analyze a duration for which the digital j unction voltage signal is within the predefined frequency range . For example , a predefined minimum time can be set for the frequency analyzer .
I f the digital j unction voltage signal comprises a frequency in the predefined frequency range and the duration of the digital j unction voltage signal with a frequency in the predefined frequency range is larger and/or equal to a predefined minimum time , the frequency analyzer can identi fy the digital j unction voltage signal as a valid signal . That the digital j unction voltage signal is identi fied as a valid signal can particularly mean that a particular movement of an obj ect in the sensing region is detected .
Alternatively or additionally, a predefined maximum time can be set for the frequency analyzer such that the digital j unction voltage signal is a valid signal i f the duration of the frequency within the predefined frequency range is smaller or equal to the maximum time . According to at least one embodiment , the trigger module comprises an output . A part of the trigger module , for example the frequency analyzer, can be configured to provide a signal to the output . The output can provide a signal to components connected with the trigger module .
According to at least one embodiment of the trigger module , the laser is configured to emit electromagnetic radiation to a sensing region outside of the trigger module . The sensing region can be part of a device comprising the trigger module . The sensing region can be arranged adj acent to the trigger module . For example , the sensing region comprises a sensing surface . The device and/or the trigger module can comprise the sensing surface . For example , the sensing surface forms an outer surface of the trigger module and/or the device . For example , the electromagnetic radiation emitted by the laser is focused to the sensing surface .
The electromagnetic radiation emitted by the laser comprised by the trigger module can be emitted to the sensing region outside of the trigger module . For example , the electromagnetic radiation emitted by the laser is focused into the sensing region .
The sensing region provides an easily accessible region for the positioning and/or movement of the obj ect .
According to at least one embodiment , the trigger module comprises a laser, a filter, an ADC, a frequency analyzer, and an output , wherein the laser is configured to emit electromagnetic radiation to a sensing region outside of the trigger module , the filter is configured to provide an analog j unction voltage signal measured across the laser, the ADC is configured to convert the analog junction voltage signal into a digital junction voltage signal, the ADC is connected with the frequency analyzer and the frequency analyzer is connected with the output.
The trigger module can be configured to detect an object and/or a movement of an object within the sensing region. When an object moves in the sensing region, electromagnetic radiation emitted by the laser is at least partially reflected back into the cavity resonator of the laser by the object, for example. This causes a modulation of the junction voltage of the laser. The obtained modulation of the analog junction voltage signal is converted into a digital junction voltage signal. The digital junction voltage signal, for example the frequencies of the digital junction voltage signal, can be compared to a predefined frequency by the frequency analyzer.
The trigger module can be active or inactive. This can mean that the trigger module can be either in an active state or in an inactive state. For example, the trigger module consumes more power when active than when inactive. That the trigger module is inactive can mean, that the trigger module is in a standby mode and/or in a sleep mode.
The trigger module has, amongst others, the advantage that it can be operated energy-efficient. The trigger module only comprises components with a low power consumption, for example, only one laser and an ADC with a low power consumption, e.g. a Schmitt-trigger .
A further advantage of the trigger module described herein is that due to the self-mixing interferometry of the laser used to detect an object, no further components and/or detectors, e.g. photodiodes are necessary. Thus, the energy consumption of the trigger module is further reduced.
A trigger module with a low power consumption leads to an increased battery life time, which is, for example, critical for ultra-mobile and/or wearable devices.
Additionally, the trigger module can be produced at low cost and formed compactly.
According to at least one embodiment, the trigger module is free of a photodiode. This means, the trigger module does not comprise any photodiode.
According to at least one embodiment, the trigger module is configured to provide an output signal provided by the frequency analyzer at its output. If the frequency analyzer detects a valid signal in the digital junction voltage signal, the frequency analyzer provides an output signal to the output of the trigger module. The output can be connected with a main system of a device, the main system being different from the trigger module and the device comprising the trigger module. For example, the signal provided at the output of the trigger module can be transmitted to the main system of the device. The signal provided at the output of the trigger module can be used to activate the main system, for example. In other words, the trigger module can be used as a wake-up trigger for the main system.
An advantage of this embodiment is that the trigger module can provide a signal at the output which can be provided to a main system. According to at least one embodiment, the ADC comprises a single-bit analog-to-digital converter, especially a Schmitt- trigger. The single-bit analog-to-digital converter can consume less electric energy than a multi-bit analog-to- digital converter.
The Schmitt-trigger can be configured to convert the analog junction voltage signal into a digital junction voltage signal. The Schmitt-trigger comprises a predefined first threshold and a predefined second threshold. When the value of the digital junction voltage signal is above a first threshold, the Schmitt-trigger returns a first value, e.g. 1. This value is maintained until the value of the digital junction voltage signal decreases below a second threshold. The Schmitt-trigger returns a second value, e.g. 0, until the value of the digital junction voltage signal increases above the first threshold.
As a single-bit ADC and/or a Schmitt-trigger operates energyefficient, the power consumed by the trigger module can be decreased .
A further advantage of this embodiment is, that a Schmitt- trigger can be used to filter noise in the provided signal with an amplitude outside a range between the first threshold and the second threshold of the Schmitt-trigger.
According to at least one embodiment, the trigger module comprises an amplifier, wherein the amplifier is arranged between the laser and the ADC along a connection. The amplifier can comprise a single-stage amplifier and/or a multi-stage amplifier. This means, the amplifier can have one or more stages.
For example, the amplifier can be arranged between the filter and the ADC along a connection.
Due to the amplifier the junction voltage signal provided by the filter can be processed, e.g. amplified, to be easier processable by the ADC, for example by the Schmitt-trigger .
According to at least one embodiment, the laser comprises a vertical-cavity surface-emitting laser diode (VCSEL) .
According to at least one embodiment, the trigger module comprises a driver, wherein the driver is configured to provide a direct current to the laser. In other words, the laser can be operated with a direct current. For example, the driver can be configured to provide a constant current to the laser .
According to at least one embodiment, the trigger module can comprise a finite state machine, wherein the finite state machine is configured to activate at least some parts of the trigger module. For example, the finite state machine can be configured to activate some parts of the trigger module. Particularly, the finite state machine can be configured to activate all parts of the trigger module. The finite state machine can be configured to activate at least the laser, the filter, the ADC and the frequency analyzer. For example, the finite state machine is configured as a switch. Due to the finite state machine , the parts of the trigger module can be easily activated .
According to at least one embodiment , the trigger module comprises an optical element , wherein the optical element is arranged between the laser and the sensing region .
The optical element can comprise a beam shaping element . For example , the optical element can be configured to shape the electromagnetic radiation emitted by the laser . For example , the optical element comprises a focusing element .
Due to the optical element , electromagnetic radiation can be easily focused to the sensing region and/or the sensing surface .
Furthermore , a device is provided . The device preferably comprises a trigger module described herein . This means all features disclosed for the trigger module are also disclosed for the device and vice-versa .
According to at least one embodiment , the device comprises a trigger module and a periodic signal generator, wherein the periodic signal generator is configured to provide a periodic signal to the trigger module . The periodic signal generator can be connected with the trigger module . The periodic signal generator can be configured to provide a periodic signal to the trigger module . For example , the periodic signal can be configured to activate the trigger module .
The trigger module can be configured to provide a pause signal to the periodic signal generator which can pause the operation of the periodic signal generator . For example , the operation of the periodic signal generator can be paused during the operation of the trigger module . The pause signal can be generated and provided to the periodic signal generator by the finite state machine , for example .
According to at least one embodiment of the device , the periodic signal generator comprises an oscillator and a timer .
The oscillator can be configured to generate an oscillating signal . For example , the oscillating signal comprises a low frequency .
The timer can be configured to allow only the transmittance of one pulse of the oscillating signal within a predetermined interval .
The periodic signal can, for example , comprise a pulse within a predetermined interval .
As the oscillator oscillates with a low frequency, the oscillator and/or the periodic signal generator operate energy-ef ficient .
According to at least one embodiment of the device , the device comprises a main system, wherein the trigger module is configured as a wake-up trigger for activating the main system, the main system is coupled to the output of the trigger module and the main system consumes more power when active than when inactive . Additionally or alternatively, the main system consumes more power during operation than the trigger module and/or the periodic signal generator consume during operation . The trigger module can be integrated with the main system or the main system can be a separate component and be connected with the main system .
As the low power consuming trigger module can be used to activate the high power consuming main system only when the main system is needed, the device can be operated energyef ficient .
According to at least one embodiment , the device comprises a sensing surface , wherein the sensing surface forms an outer surface of the device and the sensing surface adj oins the sensing region .
The sensing surface can be translucent and/or transparent for the electromagnetic radiation emitted by the laser .
The sensing surface can be translucent and/or transparent or non-transparent and/or non-translucent for electromagnetic radiation with a wavelength di f ferent from the wavelength of the electromagnetic radiation emitted by the laser .
For example , the sensing surface forms an outer surface of the trigger module and/or of the main system . The sensing surface can be a part of a cover covering the trigger module and/or the main system . Additionally or alternatively, the sensing surface can be arranged on the side of the cover facing away from the laser . Preferably, the sensing surface can be configured as a touch surface . For example , the sensing surface is configured to be touched by an obj ect , for example a finger and/or a robot arm, which taps the sensing surface and/or swipes on the sensing surface . The obj ect can thereby be at least temporarily in direct contact with the sensing surface . Due to the sensing surface , the trigger module can be touch-sensitive . In this case , the electromagnetic radiation emitted by the laser can be focused to the sensing surface .
Alternatively, the focus point of the electromagnetic radiation emitted by the laser can be positioned in the sensing region spaced apart from the sensing surface . For example , the focus point can be at least 1 mm, for example at least 5mm or at least 1 cm away from the sensing surface .
The sensing surface can adj oin the sensing region . For example , the sensing surface directly adj oins the sensing region . Preferably, the sensing surface is arranged between the laser and the sensing region . Alternatively, the sensing surface can comprise the sensing region .
The sensing surface provides an easily usable touch surface , to ensure an ef ficient recognition of the movement of the ob j ect .
According to at least one embodiment of the device , the sensing surface is translucent for the electromagnetic radiation emitted by the laser . For example , the sensing surface is translucent and/or transparent for the electromagnetic radiation emitted by the laser .
For example , the sensing surface can be translucent for ambient light . The ambient light can be not coherent with the electromagnetic radiation emitted by the laser .
This way, the electromagnetic radiation emitted by the laser can be at least partially transmitted through the sensing surface . This enables that the electromagnetic radiation emitted by the laser can be reflected by an obj ect in the sensing region and/or on the sensing surface . As the ambient light is not coherent with the electromagnetic radiation emitted by the laser, the sel f-mixing interference signal is not influenced by the ambient light .
According to at least one embodiment of the device , a transmission coef ficient of the sensing surface is higher for electromagnetic radiation emitted by the laser than for electromagnetic radiation of other wavelengths . The source for the electromagnetic radiation of other wavelengths can be ambient light , for example .
An advantage of the device according to this embodiment is that the device is not sensitive to ambient light . Therefore , the trigger module can correctly identi fy the obj ect , e . g . the finger, and therefore , the main system can be activated ef ficiently and the device can be operated ef ficiently .
Additionally, the device can also be ef ficiently operated in a bright or in a dark environment .
Furthermore , a method for operating a trigger module is provided . The trigger module described herein can preferably be operated according to the method for operating a trigger module . This means all features disclosed for the trigger module are also disclosed for the method for operating a trigger module and vice-versa .
According to at least one embodiment , the method of operating a trigger module comprises the following steps :
- providing a trigger module , - emitting electromagnetic radiation into the sensing region by the laser,
- detecting a j unction voltage of the laser,
- providing the j unction voltage to the ADC and converting it into a digital j unction voltage signal ,
- providing the digital j unction voltage signal to the frequency analyzer, and
- comparing the digital j unction voltage signal to a predefined frequency range by the frequency analyzer .
Preferably, the trigger module is a trigger module described herein .
An underlying consideration of the method described herein is to provide a method according to which an energy-ef ficient trigger module can be operated ef ficiently .
According to at least one embodiment of the method for operating a trigger module , the frequency analyzer provides an output signal to the output i f the digital j unction voltage signal is within the predefined frequency range for a predefined time . The predefined frequency range and/or the predefined time can, for example , be chosen according to the requirements , e . g . the setup and/or the movement to be detected . That the digital j unction voltage signal is within the predefined frequency range for the predefined time can mean, that the digital j unction voltage signal is a valid signal . In other words , the digital j unction voltage signal is within the predefined frequency range for the predefined time in case the obj ect performs the movement to be detected . The frequency analyzer can be connected with the output and can be configured to provide an output signal to the output . This output signal can be used as a wakeup signal for components connected with the trigger module , for example .
Due to the output , the trigger module can return a signal depending on the external input and provide the signal to subsequent components .
According to at least one embodiment of the method for operating a trigger module , the laser undergoes sel f-mixing interferometry caused by reflections and/or backscattering of the radiation emitted by the laser on an obj ect in the sensing region back into the laser . The sel f-mixing interferometry signal can, for example , be obtained by detecting the modulation of the j unction voltage measured across the laser .
An advantage of using sel f-mixing interferometry as a detection method for the positioning and/or movement of an obj ect is that this method can be used in a plurality of environments , for example in a dark or in a bright environment .
Additionally, the method does not require further components , like photodiodes , for example . Thus , the energy consumption is reduced .
Furthermore , a method for operating a device is provided . The device described herein can preferably be operated by the method for operating a device . This means all features disclosed for the device are also disclosed for the method for operating a device and vice-versa . According to at least one embodiment , the method for operating a device comprises the following steps :
- providing a trigger module , a main system and a sensing region, wherein the main system is inactive and the trigger module is active ,
- moving an obj ect in the sensing region,
- providing an output signal to the main system to activate the main system by the trigger module ,
- switching the trigger module into an inactive state .
According to at least one embodiment of the method for operating a device , the trigger module is activated by a signal provided by a periodic signal generator . The periodic signal generator can be configured to provide a periodic signal to the trigger module . The periodic signal generator can be connected with the trigger module . The periodic signal generator can be configured to provide a periodic signal to the trigger module . For example , the periodic signal can be configured to activate the trigger module .
According to at least one embodiment of the method for operating a device , the main system is connected with the periodic signal generator and after deactivation of the main system, the periodic signal generator is activated . For example , the periodic signal generator is only active when the main system is inactive . The periodic signal generator can provide a signal to the trigger module to activate the trigger module only in case the periodic signal generator is active . The main system can provide an activation signal to the periodic signal generator to activate the periodic signal generator when the main system is inactive and/or directly before deactivation of the main system . That the main system is inactive can mean that the main system is in sleep mode . In other words , inactive can also mean that the main system is in standby mode and/or in an energy saving mode . The main system can consume less power when inactive than when active .
As the periodic signal generator and/or the trigger module are only active i f the main system is inactive , the energy consumption of the device can be further reduced and the device can be operated energy-ef f iciently .
Further advantages and advantageous designs and further developments of the trigger module , the device , the method for operating a trigger module and the method for operating a device will become apparent from the following exemplary embodiments , which are described below in association with the figures .
Figure 1 shows an embodiment of a device .
Figure 2 shows a signal generated by the periodic signal generator according to an embodiment .
Figure 3 shows a flowchart of the operation of the periodic signal generator according to an embodiment .
Figure 4 shows di f ferent scenarios of operation of the trigger module .
Figure 5 shows a flowchart of the operation of the trigger module according to an embodiment .
Figures 6 and 9 show analog j unction voltage signals according to embodiments . Figures 7 , 8 and 10 show digital j unction voltage signals generated by an ADC according to embodiments .
Figure 11 shows a trigger module according to an embodiment .
Identical , similar or equivalent elements are marked with the same reference signs in the figures . The figures and the proportions of the elements represented in the figures among each other are not to be considered as true to scale . Rather, individual elements may be oversi zed for better representability and/or comprehensibility . Identical or ef fectively identical components and parts might be described only with respect to the figures where they occur first .
Their description is not necessarily repeated in successive figures .
Figure 1 shows a device 100 according to an embodiment . The device 100 comprises a periodic signal generator 1 , a trigger module 2 , and a main system 3 . Further, the device 100 can comprise a sensing surface 4 and/or a sensing region 5 . The sensing surface 4 forms an outer surface of the device 100 . The sensing surface 4 can adj oin the sensing region 5 .
The periodic signal generator 1 is configured to provide a periodic signal 12 to the trigger module 2 . The trigger module 2 can be configured to provide a pause signal 14 to the periodic signal generator 1 which can pause the operation of the periodic signal generator 1 . The periodic signal generator 1 comprises an oscillator 10 and a timer 11 . The oscillator 10 is configured to provide an oscillating signal . The timer 11 can be configured to allow only the transmittance of one pulse 15 of the oscillating signal within a predetermined interval . The trigger module 2 comprises a laser 22 , a filter 26 , an ADC 28 , a frequency analyzer 29 and an output 31 . The laser 22 can be configured to emit electromagnetic radiation 24 to a sensing region 5 outside of the trigger module 2 and/or to a sensing surface 4 . The laser 22 can comprise a verticalcavity surface-emitting laser diode . The laser 22 can be configured to undergo sel f-mixing interferometry caused by reflections and/or backscattering of the electromagnetic radiation 24 emitted by the laser 22 on an obj ect 6 in the sensing region 5 and/or on the sensing surface 4 back into the laser 22 .
The filter 26 can be configured to provide an analog j unction voltage signal measured across the laser 22 .
The ADC 28 can be configured to convert the analog j unction voltage signal into a digital j unction voltage signal . The ADC 28 can comprise a single-bit analog-to-digital converter . For example , the ADC 28 comprises a Schmitt-trigger . The ADC 28 is connected with the frequency analyzer 29 . The frequency analyzer 29 can be configured to compare the digital j unction voltage signal to a predefined frequency range and to a predefined time . The frequency analyzer 29 is connected with the output 31 . The trigger module 2 can be configured to provide an output signal 30 provided by the frequency analyzer 29 at its output 31 . For example , the frequency analyzer 29 provides an output signal 30 to the output 31 of the trigger module 2 i f the digital j unction voltage signal is within the predefined frequency range for the predefined time . The trigger module 2 comprises an ampli fier 27 . The filter 26 and the ampli fier 27 are arranged between the laser 22 and the ADC 28 along a connection .
The trigger module 2 further comprises a driver 21 . The driver 21 can be configured to provide a direct current , for example a constant current , to the laser 22 .
Additionally, the trigger module 2 comprises a finite state machine 20 . The finite state machine 20 can be configured to activate at least some parts of the trigger module 2 . For example , the finite state machine 20 can be configured to activate all parts of the trigger module 2 . The expression "all parts" can, in particular, refer to the driver 21 , the laser 22 , the filter 26 , the ampli fier 27 , the ADC 28 and to the frequency analyzer 29 . The finite state machine 20 can, for example , be configured as a switch .
The trigger module 2 also comprises an optical element 23 . The optical element 23 is arranged between the laser 22 and the sensing surface 4 and/or the sensing region 5 . For example , the sensing surface 4 is translucent for the electromagnetic radiation 24 emitted by the laser 22 . The sensing surface 4 can comprise a transmission coef ficient . The transmission coef ficient of the sensing surface 4 can be higher for electromagnetic radiation 24 emitted by the laser 22 than for electromagnetic radiation of other wavelengths .
The trigger module 2 can be configured as a wake-up trigger for activating the main system 3 . The main system 3 is coupled to the output 31 of the trigger module 2 . The main system 3 can consume more power when active than when inactive . The main system 3 can provide an activation signal 13 to the periodic signal generator 1 to activate the periodic signal generator 1 .
Figure 2 shows a signal generated by the periodic signal generator 1 according to an embodiment . The signal can comprise pulses 15 that occur repeatedly . For example , one pulse 15 occurs at certain intervals . The interval can have a certain length Tl . During the time T1 the signal comprises one pulse 15 . The signal length Tl and/or the interval between two temporally adj acent pulses can be set by the timer 11 .
Figure 3 shows a flowchart of the method of operation of the periodic signal generator 1 according to an embodiment . In a first step S I , the periodic signal generator 1 checks i f the main system 3 is inactive . That the main system 3 is inactive can particularly mean that the main system 3 is in sleep mode . While the main system 3 is active ( indicated with path N) , no further steps of the periodic signal generator 1 are executed .
When the main system 3 is inactive ( indicated with path Y) , in a step S2 , the periodic signal generator 1 generates the periodic signal 12 . The periodic signal 12 is provided to the trigger module 2 . For example , the signal is provided to the finite state machine 20 of the trigger module 2 . The finite state machine 20 can be configured to activate at least some parts of the trigger module 2 . The trigger module 2 can provide the pause signal 14 to the periodic signal generator 1 .
In a third step, S3 , the periodic signal generator 1 checks i f the pause signal 14 is received . The periodic signal generator 1 generates the periodic signal 12 as long as the trigger module 2 does not provide the pause signal 14 (path N) . Alternatively, the trigger module 2 provides the pause signal 14 to the periodic signal generator 1 (path Y) .
The periodic signal generator 1 , step S4 , is paused as long as the pause signal 14 is received . The trigger module 2 can stop to provide the pause signal 14 to the periodic signal generator 1 . Alternatively, the periodic signal generator 1 is paused until a reactivation signal is received from the trigger module 2 and/or until the activation signal 13 is received from the main system 3 .
Then, in a next step, S5 , the timer is reset and the periodic signal generator 1 continues with step S I .
Figure 4 shows di f ferent scenarios of operation of the trigger module . The line LI indicates the enable-pulse 15 in the periodic signal provided to the trigger module 2 by the periodic signal generator 1 .
In a first scenario , line L2 , the trigger module 2 is in standby mode Ml . The enable-pulse 15 is provided to the trigger module 2 . Then, the trigger module 2 is activated . In the first scenario L2 , no obj ect moves in the sensing region 5 . Therefore , in a mode M2 , no modulated j unction voltage signal and/or no frequency is detected by the trigger module 2 . The trigger module 2 then switches back to the standby mode Ml .
In a second scenario , line L3 , first , the trigger module 2 is in the standby mode Ml . The enable-pulse 15 is provided to the trigger module 2 . The finite state machine 20 of the trigger module 2 is configured to activate at least some parts of the trigger module 2 after receiving the enablepulse 15. The finite state machine 20 can particularly activate all parts of the trigger module 2. In a mode M3 of the trigger module 2, a modulation in the junction voltage signal /frequency is detected. In a mode M4, it is determined that the detected frequency is not a valid signal. This can be determined by the frequency analyzer 29. For example, the detected frequency is not within the predefined frequency range. Alternatively or additionally, the time of the signal with the detected frequency does not last for the predefined time. Then, the trigger module switches to the standby mode Ml . The trigger module 2 can remain in the standby mode Ml until an enable-pulse 15 from the periodic signal generator 1 is received.
The third scenario, L4, differs from the second scenario L3, in that in the third scenario L4 the trigger module 2 detects a valid signal, M5. Then, in mode M6, the trigger module 2 generates an output signal 30, which can be provided to a main system 3 at the output 31 of the trigger module 2. In mode M7 the timer 11 is paused.
Figure 5 shows a flowchart of the operation of the trigger module 2 according to an exemplary embodiment. In a start configuration S20, the trigger module 2 is in standby mode. This means, the trigger module 2 is inactive, consuming less power than when the trigger module 2 is active.
In a next step S21, the trigger module 2 checks, if the periodic signal 12 is received. For example, the periodic signal 12 can be provided to the trigger module 2 by the periodic signal generator 1. This step is repeated until a periodic signal 12 is received (path N) . I f a periodic signal 12 is received (path Y) , in a subsequent step S22 , at least some parts of the trigger module 2 are activated . For example , all parts of the trigger module 2 are activated . The parts of the trigger module 2 can be activated by the finite state machine 20 , for example .
In a next step S23 , the trigger module 2 checks whether a modulated signal is available . I f no modulation on the j unction voltage across the laser is detected, the trigger module 2 returns to the start configuration shown in step S20 (path N) .
I f a modulation is detected (path Y) , the frequency analyzer 29 compares the digital j unction voltage signal to a predefined frequency and to a predefined time . I f no frequency of the digital j unction voltage signal , the converted sel f-mixing interferometry signal , is within the predefined frequency range or a frequency is not within the predefined frequency range for the predefined time , the trigger module 2 returns to the start configuration S20 .
I f a frequency in the digital j unction voltage signal is within the predefined frequency range for a predefined duration, the frequency analyzer 2 identi fies the signal as a valid signal (path Y) .
In step S26 , an output signal 31 is provided to the main system 3 .
In a next step S27 , the trigger module provides a pause signal 14 to the periodic signal generator 1 to pause the timer 11 . After the time period in which the timer is paused, step S28, the timer 11 is reactivated by the trigger module
2, step S29, and the trigger module 2 returns to the start configuration S20.
Figure 6 shows a modulation on the analog junction voltage signal according to an exemplary embodiment. The signal can, for example, be received for an object 6 swiping on the sensing surface 4. On the x-axis, the time is displayed in seconds (s) and on the y-axis the voltage is shown in volt (V) .
Figure 7 shows a digital junction voltage signal generated by an ADC 28 according to an exemplary embodiment. For example, the digital junction voltage signal is generated by the conversion of the analog junction voltage signal depicted in figure 6 by a Schmitt-trigger . The digital junction voltage signal shown in figure 7 can be provided to the frequency analyzer 29. On the x-axis, the time is displayed in seconds (s) and on the y-axis the possible values of the ADC 28 are shown .
Figure 8 shows a digital junction voltage signal generated by an ADC 28 according to an exemplary embodiment. The digital junction voltage signal shown here can alternatively be generated by a comparator. For example, the signal shown in figure 8 is a zoom-in of the digital junction voltage signal shown in figure 7. The digital junction voltage signal comprises different frequencies. The signal can be identified as a valid signal by the frequency analyzer 29 if one frequency or at least one of the frequencies is within the predefined frequency range for the predefined time. On the y- axis the possible values of the ADC 28 are shown. Figure 9 shows a modulation on the analog junction voltage signal according to an exemplary embodiment. The signal can, for example, be received for an object 6 tapping on the sensing surface 4. On the x-axis, the time is displayed in seconds (s) and on the y-axis the voltage is shown in volt (V) .
Figure 10 shows a digital junction voltage signal generated by an ADC 28 according to an exemplary embodiment. For example, the digital junction voltage signal is generated by the conversion of the analog junction voltage signal depicted in figure 9 by a Schmitt-trigger . On the x-axis, the time is displayed in seconds (s) and on the y-axis the possible values of the ADC 28 are shown.
Figure 11 shows a trigger module 2 according to an embodiment. The trigger module 2 comprises a driver 21, a laser 22, a filter 26, an amplifier 27, an ADC 28 and a frequency analyzer 29. The filter 26 comprises a resistor 26a and two capacitors 26b. The amplifier 27 is connected to the laser 22 in parallel. On each connection from the laser 22 to the amplifier 27 one capacitor 26b is arranged. The resistor 26a is arranged along a connection between the driver 21 and the laser 22. The filter 26 can be a high pass filter and/or a DC blocking filter, for example. The ADC 28 can be a Schmitt-trigger .
The invention described herein is not limited by the description given with reference to the embodiments. Rather, the invention encompasses any novel feature and any combination of features, including in particular any combination of features in the claims, even if this feature or this combination is not itself explicitly indicated in the claims or embodiments.
This patent application claims the priority of German patent application 10 2022 123 450.9, the disclosure content of which is hereby incorporated by reference.
References
1 periodic signal generator
2 trigger module
3 main system
4 sensing surface
5 sensing region
6 obj ect
10 oscillator
11 timer
12 periodic signal
13 activation signal
14 pause signal
15 enable pulse
20 finite state machine
21 driver
22 laser
23 optical element
24 radiation
26 filter
26a resistor
26b capacitor
27 amp 1 i f i e r
28 analog-to-digital converter (ADC )
29 frequency analyzer
30 output signal
31 output
34 reflected and/or backscattered radiation
100 device

Claims

Claims
1. Trigger module (2) , comprising:
- a laser ( 22 ) ,
- a filter (26) ,
- an analog-to-digital converter (28) ,
- a frequency analyzer (29) , and
- an output (31) , wherein
- the laser (22) is configured to emit electromagnetic radiation (24) to a sensing region (5) outside of the trigger module (2) ,
- the filter (26) is configured to provide an analog junction voltage signal measured across the laser (22) ,
- the analog-to-digital converter (28) is configured to convert the analog junction voltage signal into a digital junction voltage signal,
- the analog-to-digital converter (28) is connected with the frequency analyzer (29) , and
- the frequency analyzer (29) is connected with the output ( 31 ) .
2. Trigger module (2) according to the previous claim, wherein the trigger module (2) is configured to provide an output signal (30) provided by the frequency analyzer (29) at its output (31) .
3. Trigger module (2) according to one of the previous claims, wherein the analog-to-digital converter (28) comprises a single-bit analog-to-digital converter.
4. Trigger module (2) according to one of the previous claims, further comprising an amplifier (27) , wherein the amplifier (27) is arranged between the laser (22) and the analog-to-digital converter (28) along a connection. Trigger module (2) according to one of the previous claims, wherein the laser (22) comprises a verticalcavity surface-emitting laser diode. Trigger module (2) according to one of the previous claims, further comprising a driver (21) , wherein the driver (21) is configured to provide a direct current to the laser ( 22 ) . Trigger module (2) according to one of the previous claims, further comprising a finite state machine (20) , wherein the finite state machine (20) is configured to activate at least some parts of the trigger module (2) . Trigger module (2) according to one of the previous claims, further comprising an optical element (23) , wherein
- the optical element (23) is arranged between the laser (22) and the sensing region (5) . Device (100) comprising a trigger module (2) according to one of the previous claims and further comprising a periodic signal generator (1) , wherein
- the periodic signal generator (1) is configured to provide a periodic signal (12) to the trigger module
(2) . Device (100) according to the previous claim, wherein the periodic signal generator (1) comprises an oscillator
(10) and a timer (11) . Device (100) according to one of the claims 9 to 10, further comprising a main system (3) , wherein
- the trigger module (2) is configured as a wake-up trigger for activating the main system (3) ,
- the main system (3) is coupled to the output (31) of the trigger module (2) , and
- the main system (3) consumes more power when active than when inactive. Device (100) according to one of the claims 9 to 11, further comprising a sensing surface (4) , wherein the sensing surface (4) forms an outer surface of the device (100) and the sensing surface (4) adjoins the sensing region ( 5 ) . Device (100) according to the previous claim, wherein the sensing surface (4) is translucent for the electromagnetic radiation (24) emitted by the laser (22) . Device (100) according to one of the claims 12 to 13, wherein a transmission coefficient of the sensing surface (4) is higher for electromagnetic radiation (24) emitted by the laser (22) than for electromagnetic radiation of other wavelengths. Method of operating a trigger module (2) , the method comprising :
- providing a trigger module (2) according to one of the claims 1 to 8,
- emitting electromagnetic radiation (24) into the sensing region (5) by the laser,
- detecting a junction voltage of the laser (22) , - providing the analog junction voltage signal to the analog-to-digital converter (28) and converting it into a digital junction voltage signal,
- providing the digital junction voltage signal to the frequency analyzer (29) , and
- comparing the digital junction voltage signal to a predefined frequency range by the frequency analyzer (29) . Method for operating a trigger module (2) according to the previous claim, wherein the frequency analyzer (29) provides an output signal (30) to the output (31) if the digital junction voltage signal is within the predefined frequency range for a predefined time. Method for operating a trigger module (2) according to one of the two preceding claims, wherein
- the laser (22) undergoes self-mixing interferometry caused by reflections and/or backscattering of the electromagnetic radiation (24) emitted by the laser (22) on an object (6) in the sensing region (5) back into the laser (22) . Method for operating a device (100) , the method comprising :
- providing a trigger module (2) according to one of the claims 1 to 8, a main system (3) and a sensing region (5) , wherein the main system (3) is inactive and the trigger module (2) is active,
- moving an object (6) in the sensing region (5) ,
- providing an output signal (30) to the main system (3) to activate the main system (3) by the trigger module
( 2 ) , and - switching the trigger module (2) into an inactive state . Method for operating a device (100) according to the previous claim, wherein the trigger module (2) is activated by a signal provided by a periodic signal generator ( 1 ) . Method for operating a device (100) according to one of the claims 18 to 19, wherein
- the main system (3) is connected with the periodic signal generator (1) , and
- after deactivation of the main system (3) , the periodic signal generator (1) is activated.
PCT/EP2023/071520 2022-09-14 2023-08-03 Trigger module, device, method for operating a trigger module and method for operating a device WO2024056271A1 (en)

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DE102022123450 2022-09-14

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