Circuit for remote control, system and method

Abstract

The invention relates to a circuit (2) for remote control, comprising: An infrared light pattern generator (4), a switch (6) and a light emitting device (8), characterized in that the light emitting device is configured as a laser diode. The invention further relates to a system with such a circuit and to a method, in particular combined with a dToF sensor.

Description

[0001] 2024PF01320 1

[0002] CIRCUIT FOR REMOTE CONTROL , SYSTEM and METHOD

[0003] DESCRIPTION

[0004] TECHNICAL FIELD

[0005] The invention concerns a circuit for a remote control , a system comprising the circuit as well as a method for operating the circuit .

[0006] BACKGROUND

[0007] Remote controls using infrared ( IR) light are known for a variety of applications , for example for switching a Screen on or of f . A typical wiring diagram for such remote control is depicted in FIG . 1 . The circuit 2 comprises an IR pattern generator 4 . The pattern is typically adapted for providing a control signal for a certain function of the controlled device , having an IR signal receiver . The circuit further comprises a light emitting diode ( LED) 8 , being connected to a supply voltage VDD . A switch 6 is placed between the IR pattern generator 4 and the LED 8 , for switching the LED on and of f depending on the pattern of the IR pattern generator . In a typical operation mode , the generated IR signal has a duty cycle of 25 % and a frequency of 38 kHz .

[0008] Such a circuit is typically integrated into a stand-alone remote control , however, i f a remote control function is to be integrated in a multi functional device , such as a camera or a mobile phone having for example an autofocus or a distance measurement function, this adds up another circuit which increases the required installation space .

[0009] SUMMARY

[0010] In accordance with an aspect of the invention a circuit for remote control is provided, the remote control comprising : 2024PF01320 2

[0011] An infrared light pattern generator, a switch and a light emitting device, characterized in that the light emitting device is configured as a pulsed laser diode, which is configured to be run with short pulses at high frequencies, in particular in the MHz range. Thus, the laser diode is configured as a pulsed laser diode. The infrared light pattern generator is configured to generate a pattern in a typical remote control frequency range, in particular in the kHz range, e.g. 36 kHz - 40 kHz, for example 38 kHz.

[0012] According to one embodiment, the laser diode is a Vertical cavity surface emitting laser (VCSEL) . The lasing threshold of such a VCSEL varies from VCSEL to VCSEL and changes over temperature. In order to run a VCSEL in stable condition, there is a need to be operated sufficiently high above lasing threshold. For not exceeding the eye safety limit and / or not dissipating too much power or even damage the VCSEL, such a VCSEL may be operated in a pulsed mode.

[0013] According to one embodiment, the switch is implemented by a Time-of-Flight control circuit.

[0014] According to one embodiment, the time-of-f light control circuit comprises a controller, a driver, a detector unit and a data processing unit, in particular wherein the detector unit comprises a single photon avalanche and a time-to-digital conversion unit wherein optionally one or more optical filter are connected to the detector unit.

[0015] According to one embodiment the driver is provided with a charge pump and a NMOS driver. In particular, the driver is a VCSEL driver for driving a VCSEL. The driver might be configured as the driver of the time-of-f light control circuit.

[0016] According to one embodiment, the laser diode is provided with a diffuser optics. The diffuser optics is in particular necessary, if the signal is to be received in a larger area. The diffuser optics may be a controllable optics which might be set to a predetermined widening of the beam. 2024PF01320 3

[0017] According to one embodiment , the circuit is provided with an external capacitor, which is in particular connected in parallel with the charge pump of the driver . The additional capacitor is charged when IR remote operation is of f and discharged when IR remote operation is on, thus the laser diode , in particular VCSEL, is driven for emitting a light in accordance with the generated IR pattern of the IR pattern generator, which might lead under the assumption of a typical duty cycle of 25 % to an increase of power by the factor of 4 .

[0018] According to one embodiment , the laser diode is configured to be run with short pulses at 40 MHz or similar frequencies . In particular, the laser diode might be configured to be operated at the same frequence in a remote control mode as for a time of flight mode , in particular direct time of flight mode (dTOF) . This short pulses at high frequencies are to be over- layed with the frequency of the typical IR signal frequency, which is for example 38 kHz .

[0019] According to one embodiment , the circuit is configured for providing a remote control signal and for providing a distance measurement . In particular, the IR pattern generator is activated for providing a remote control signal and deactivated for providing a distance measurement , in particular by dTOF . In particular, an emission of the light signal as remote control signal and an emission of the light signal for a distance measurement in particular via time-of- f light is a light emission by the same light emitting device , being a laser diode , wherein in particular the light emission is either used as remote control signal or as signal for the distance measurement .

[0020] In accordance with an aspect of the invention a system is provided, the system comprising the circuit as described above . 2024PF01320 4

[0021] According to one embodiment , the system is a handheld user device . Such a handheld device might be for example a mobile phone device , a tablet or a camera .

[0022] According to one embodiment , the system is provided with a distance measurement function, in particular with a dTOF sensor, and / or the system is provided with a camera module having an autofocus function .

[0023] In particular, the handheld device might be provided with a autofocus function based on a time-of- f light measurement .

[0024] In accordance with an aspect of the invention a method for providing an IR remote control signal , in particular with the circuit and / or the system described above , the signal comprising :

[0025] - Providing a pattern and

[0026] - driving the laser diode , which is configured to be run with short pulses at high frequencies , with the pattern .

[0027] According to one embodiment , driving the laser diode with the pattern comprises overlaying the pattern with a high frequency short pulse signal , in order to reduce the overall power consumption and / or re-use of the existing VCSEL and VCSEL driver . The overlay pattern might be directly provided by the IR pattern generator or the IR pattern generator provides a first signal with a first frequency which is over- layed with a higher second frequency in the time-of- f light control circuit .

[0028] These and other features , embodiments , obj ectives , and advantages of the invention will become apparent from the subsequent description . 2024PF01320 5

[0029] BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Exemplary embodiments of the invention are discussed below with reference to the accompanying drawings

[0031] FIG . 1 Circuit of a IR remote control according to the state of the art ,

[0032] FIG . 2 Circuit according to a first embodiment , and

[0033] FIG . 3 Circuit according to a second embodiment .

[0034] DETAILED DESCRIPTION

[0035] FIG . 2 shows a circuit 2 according to a first embodiment . The circuit is provided with an IR pattern generator 4 as well as a time-of- f light control circuit 11 as well as with a VCSEL 10 as light emitting device 8 . The time-of- f light control circuit 11 comprises a controller 16 , which controls the driver 14 of the VCSEL 8 in dependence of the generated pattern of the IR pattern generator 4 . The VCSEL 10 emits a laser beam which is di f fused by the optics 12 . The controller 16 and the driver 14 is in particular adapted to drive the VCSEL 10 in such a way to emit a pulsed laser beam for being able to operate the VCSEL at suf ficiently high power above the lasing threshold without exceeding an eye safety limit or dissipate too much power or damage the VCSEL . The pulsed laser might be for example in the order of 40 MHz which would be in the same order as the frequency for dTOF operation . In particular this frequency is far higher than the pattern generated by the IR pattern generator such that the signal overlay does not degenerated the IR pattern signi ficantly .

[0036] The circuit 2 is further provided with a detection unit 17 which may comprise a single photon avalanche and a time-to- digital conversion unit . An optical filter 19 might be provided for enhancing the detected signal for the time of flight measurement . The detection unit 17 is further connected to a data processing unit 18 , which might be provided 2024PF01320 6 with a function for converting the measurement output into a distance measurement output .

[0037] FIG . 3 shows a second embodiment of such a circuit 2 . This circuit is provided with the same features as the circuit of the first embodiment . Additionally a capacitor 20 is added, which is in particular connected in parallel with the charge pump, which might be connected to a further switch 22 . The additional capacitor is charged when IR remote operation is of f and discharged when IR remote is on, for enhancing the power output when working as remote control .

[0038] 2024PF01320 7

[0039] LIST OF REFERENCE SIGNS

[0040] Circuit 2

[0041] IR Pattern Generator 4 Switch 6

[0042] LED 8

[0043] VCSEL 10

[0044] Time-of-Flight control circuit 11

[0045] Optics 12 Driver 14

[0046] Controller 16

[0047] Detection unit 17

[0048] Data processing unit 18

[0049] Filter 19 Capacitor 20

[0050] Switch 22

Claims

2024PF01320 8CLAIMS1. Circuit (2) for remote control, comprising:An infrared light pattern generator (4) , a switch (6) and a light emitting device (8) , characterized in that the light emitting device is configured as a laser diode, being a laser diode configured to be run with short pulses at high frequencies.

2. Circuit (2) according to claim 1, wherein the laser diode is a Vertical cavity surface emitting laser (VCSEL) (10) .

3. Circuit (2) according to claim 1 or 2, wherein the switch(6) is implemented by a Time-of-Flight control circuit (11) .

4. Circuit (2) according to claim 3, wherein the time-of- flight control circuit (11) comprises a controller (16) , a driver (14) , a detector unit (17) and a data processing unit (18) , in particular wherein the detector unit (17) comprises a single photon avalanche and a time-to-digital conversion unit, wherein optionally one or more optical filter (19) are connected to the detector unit (17) .

5. Circuit (2) according to one of the preceding claims , comprising a driver (14) , in particular the driver (14) of the time-of flight control circuit (11) , the driver (14) being provided with a charge pump and a NMOS driver.

6. Circuit (2) according to one of the preceding claims, wherein the laser diode is provided with a diffuser optics(12) .

7. Circuit (2) according to one of the preceding claims, wherein the circuit (2) is provided with an external capacitor (20) , which is in particular connected in parallel with the charge pump.2024PF01320 98. Circuit (2) according to one of the preceding claims, wherein the laser diode is configured to be run at 40 MHz or similar frequencies.

9. Circuit (2) according to one of the preceding claims, wherein the circuit (2) is configured for providing a remote control signal and for providing a distance measurement.

10. System comprising the circuit according to one of claims 1 to 9.

11. System according to claim 10, wherein the system is a handheld user device.

12. System according to claim 10 or 11, wherein the system is provided with a distance measurement function, in particular with a dToF sensor, and / or wherein the system is provided with a camera module having an autofocus function.

13. Method for providing an IR remote control signal, comprising :- Providing a pattern and- driving a laser diode, which is configured to be run with short pulses at high frequencies, with the pattern.

14. Method according to claim 13, wherein driving the laser diode with the pattern comprises overlaying the pattern with a high frequency short pulse signal, in order to re-use an already existing VCSEL and VCSEL driver designed for ToF operation .

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