Augmented reality equipment, light supplement lamp control circuit thereof and camera module

Abstract

The invention provides an augmented reality device and a fill-in light control circuit and a camera module thereof, the fill-in light control circuit is composed of a control circuit, a signal modulation circuit and a fill-in light driving circuit, the control circuit respectively outputs a first PWM signal and a second PWM signal of a first frequency and a second frequency, the second PWM signal drives a camera to expose, and the signal modulation circuit is connected with the control circuit. The first PWM signal and the second PWM signal are output to the light supplement lamp driving circuit after being subjected to signal superposition modulation, so that a light supplement lamp driving signal with a corresponding size is output to the light supplement lamp, and the light supplement lamp performs light supplement work in a camera exposure time period and does not perform light supplement work in a camera non-exposure time period through signal superposition modulation. And the overall power consumption of the camera module and the augmented reality equipment is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of extended reality devices, and in particular relates to an extended reality device and a fill light control circuit and a camera module thereof. Background Art

[0002] Extended Reality (XR) devices refer to devices that use hardware devices combined with a variety of technical means to integrate virtual content and real scenes. They can be classified into AR (Augmented Reality) devices, VR (Virtual Reality) devices, MR (Mixed Reality) devices, etc.

[0003] Extended reality devices extend to all walks of life, such as AR medical glasses used in the field of medical technology. AR medical glasses are used to assist surgeons in completing the real-time spatial navigation of instruments. Among them, the extended reality device is equipped with a camera module, which is equipped with an infrared camera and a fill light. The camera completes the corresponding image acquisition work, such as the infrared camera in AR medical glasses, based on patient registration and real-time tracking of instruments during surgery.

[0004] Among them, the camera exposure requires the fill light to provide additional brightness supplement. In order to meet the high brightness requirement and the low power consumption requirement at the same time, however, the current fill light control scheme controls the fill light brightness by continuously using PWM (Pulse Width Modulation), that is, the camera fill light continues to emit light during the non-exposure time, resulting in increased power consumption and heat of the entire extended reality device, which may even affect the normal operation of the entire system in severe cases. Summary of the invention

[0005] The purpose of the present invention is to provide a fill light control circuit for an extended reality device, aiming to solve the problem of high power consumption in traditional fill light control solutions.

[0006] A first aspect of an embodiment of the present invention provides a fill light control circuit of an extended reality device, which is used to control a fill light to fill light a camera. The fill light control circuit includes:

[0007] A control circuit is configured to output a first PWM signal of a first frequency and a second PWM signal of a second frequency, wherein the second PWM signal is an exposure control signal of the camera, and the first frequency is greater than the second frequency;

[0008] a signal modulation circuit connected to the control circuit and configured to perform signal superposition on the first PWM signal and the second PWM signal to output a modulation signal;

[0009] The fill light driving circuit is connected to the signal modulation circuit and the fill light, and is configured to generate a fill light driving signal according to the modulation signal to drive the fill light to perform fill light operation.

[0010] Optionally, the control circuit is further configured to:

[0011] Obtaining the image grayscale information of the camera and comparing it with a preset image grayscale value;

[0012] When the grayscale value of the image grayscale information is greater than the preset image grayscale value, reducing the duty cycle and / or frequency of the first PWM signal;

[0013] When the grayscale value of the image grayscale information is less than the preset image grayscale value, increasing the duty cycle and / or frequency of the first PWM signal;

[0014] When the grayscale value of the image grayscale information is equal to the preset image grayscale value, the duty cycle and frequency of the first PWM signal are maintained.

[0015] Optionally, the fill light driving circuit includes:

[0016] A power supply circuit is configured to convert the input power supply into a voltage so as to output a working power supply of a preset magnitude;

[0017] A constant current driving circuit is connected to the power supply circuit, the fill light and the signal modulation circuit, and is configured to output a constant driving current to the fill light according to the modulation signal, the output frequency of the driving current is consistent with the output frequency of the modulation signal, and the duty cycle of the driving current is consistent with the duty cycle of the modulation signal.

[0018] Optionally, the power supply circuit includes a boost circuit or a buck circuit.

[0019] Optionally, the constant current driving circuit includes:

[0020] A constant current source circuit is connected to the output end of the fill light and is configured to output a constant driving current to the fill light;

[0021] The current regulating circuit is connected to the constant current source circuit and the signal modulation circuit, and is configured to adjust the output state of the constant current source circuit according to the modulation signal so that the output frequency of the driving current is consistent with the output frequency of the modulation signal, and the duty cycle of the driving current is consistent with the duty cycle of the modulation signal.

[0022] Optionally, the constant current source circuit includes a second electronic switch tube, an operational amplifier, a voltage source and a resistor;

[0023] The first end of the second electronic switch tube is connected to the output end of the fill light, the second end of the second electronic switch tube is connected to the first end of the resistor, the first end of the resistor is also connected to the inverting input end of the operational amplifier, the second end of the resistor is grounded, the power supply end of the voltage source is connected to the non-inverting input end of the operational amplifier, and the output end of the operational amplifier is connected to the control end of the second electronic switch tube through the current regulating circuit.

[0024] Optionally, the current regulating circuit includes a third electronic switch tube;

[0025] The first end of the third electronic switch tube is connected to the output end of the operational amplifier, and the second end of the third electronic switch tube is connected to the control end of the second electronic switch tube.

[0026] Optionally, the signal modulation circuit includes:

[0027] An AND gate, wherein an input terminal of the AND gate is connected to a signal output terminal of the control circuit, and the AND gate is configured to receive the first PWM signal and the second PWM signal to output the modulated signal.

[0028] A second aspect of an embodiment of the present invention provides a camera module of an extended reality device, including a camera, a fill light, and the fill light control circuit of the extended reality device as described above.

[0029] A third aspect of an embodiment of the present invention provides an extended reality device, including the camera module of the extended reality device as described above.

[0030] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: the fill light control circuit of the above-mentioned extended reality device is composed of a control circuit, a signal modulation circuit and a fill light driving circuit, the control circuit outputs a first PWM signal and a second PWM signal of a first frequency and a second frequency respectively, the second PWM signal drives the camera to expose, the first PWM signal and the second PWM signal are output to the fill light driving circuit after signal superposition modulation, thereby outputting a fill light driving signal of corresponding size to the fill light, and through signal superposition modulation, the fill light performs fill light work during the camera exposure period, and does not perform fill light work during the camera non-exposure period, thereby reducing the overall power consumption of the camera module and the extended reality device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 A schematic diagram of a first module of a camera module provided by an embodiment of the present invention;

[0033] Figure 2 A waveform diagram of signal modulation provided by an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of a first module of a fill light driving circuit provided by an embodiment of the present invention;

[0035] Figure 4 A second module schematic diagram of the fill light driving circuit provided by an embodiment of the present invention;

[0036] Figure 5 A third module schematic diagram of the camera module provided by an embodiment of the present invention;

[0037] Figure 6 A circuit diagram of a fill light driving circuit provided by an embodiment of the present invention;

[0038] Figure 7 A waveform diagram of a PWM signal provided by an embodiment of the present invention;

[0039] Figure 8 A waveform diagram of a modulation signal provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0042] Extended reality devices refer to devices that use hardware devices combined with multiple technical means to integrate virtual content and real scenes. They are new devices that "seamlessly" integrate real-world information and virtual-world information. They can be applied to different technical fields, such as AR medical glasses in the medical technology field. Surgeons can use AR medical glasses to complete the real-time spatial navigation function of medical instruments.

[0043] The extended reality device and the camera module 1 therein include a camera 200 and a fill light 120, and a corresponding control circuit. The control circuit controls the fill light 120 to fill light the camera 200, thereby providing additional brightness supplement for the exposure period of the camera 200 and meeting the high brightness requirement.

[0044] Among them, in the traditional control scheme of the fill light 120, the fill light 120 continues to emit light during the non-exposure period of the camera 200, resulting in increased power consumption of the entire extended reality device. In order to solve the problem of high power consumption of the traditional control scheme of the fill light 120 and reduce the power consumption of the camera module 1 and the extended reality device, the first aspect of the embodiment of the present invention proposes a fill light control circuit 110, such as Figure 1 As shown, the fill light control circuit 110 includes:

[0045] The control circuit 10 is configured to output a first PWM signal PWMa of a first frequency and a second PWM signal PWMb of a second frequency, wherein the second PWM signal PWMb is an exposure control signal of the camera 200, and the first frequency is greater than the second frequency;

[0046] The signal modulation circuit 20 is connected to the control circuit 10 and is configured to perform signal superposition on the first PWM signal PWMa and the second PWM signal PWMb to output a modulation signal PWMc;

[0047] The fill light driving circuit 30 is connected to the signal modulation circuit 20 and the fill light 120 , and is configured to generate a fill light driving signal according to the modulation signal PWMc to drive the fill light 120 to perform fill light operation.

[0048] In this embodiment, the control circuit 10 may adopt structures such as a signal source and a signal generator, and may also adopt structures such as a controller and a processor. After the camera module 1 is turned on, the control signal outputs a first PWM signal PWMa of a first frequency and a second PWM signal PWMb of a second frequency according to the received trigger instruction or trigger operation, wherein the second frequency of the second PWM signal PWMb is the exposure frequency of the camera 200, and its size is set according to the exposure requirement of the camera 200. In an optional embodiment, the second frequency ranges from 60Hz to 72Hz, and the duty cycle of the second PWM signal PWMb can also be set according to requirements, such as Figure 2As shown, within the scope of each frame of exposure, when the level of the second PWM signal PWMb is high, the camera 200 switches to the exposure period and performs exposure sampling to acquire images, thereby completing real-time tracking based on patient registration and intraoperative instruments; and within the scope of each frame of exposure, when the level of the second PWM signal PWMb is switched to a low level, the camera 200 switches to the non-exposure period and does not perform exposure work. The camera 200 switches between exposure and non-exposure under the drive of the second PWM signal PWMb, thereby completing the acquisition of multiple frames of image information.

[0049] The first PWM signal PWMa is the fill light driving signal that originally continuously drives the fill light driving circuit 30 to work, thereby controlling the fill light 120 to continuously emit light. The first frequency and duty cycle of the first PWM signal PWMa are adjusted according to the image brightness. The first frequency of the first PWM signal PWMa is much greater than the second frequency of the second PWM signal PWMb. In an optional embodiment, the first frequency of the first PWM signal PWMa is 10KHz, and the duty cycle is 50%.

[0050] The generated first PWM signal PWMa and the second PWM signal PWMb are also synchronously output to the signal modulation circuit 20, and the signal modulation circuit 20 performs signal superposition modulation on the two PWM signals, such as Figure 2 As shown, the modulation signal PWMc generated after modulation has a frequency of 60Hz, and has a carrier signal of 10KHz and a duty cycle of 50% in the high level. The modulation signal PWMc is output to the fill light driving circuit 30, and the fill light driving circuit 30 correspondingly outputs the fill light driving signal to the fill light 120. Through signal modulation, during the exposure period of the camera 200, that is, when the second PWM signal PWMb is at a high level, the modulation signal PWMc has the same frequency and duty cycle as the original first PWM signal PWMa, and the fill light driving circuit 30 normally drives the fill light 120 to perform the fill light work of the camera 200 exposure, and during the non-exposure period of the camera 200, that is, when the second PWM signal PWMb is at a low level, the modulation signal PWMc is synchronously modulated to a low level, the fill light driving circuit 30 stops driving, and the fill light 120 remains off, and the camera 200 fill light work is not performed, thereby reducing the overall power consumption of the camera module 1 and the extended reality device, and meeting the low power consumption requirement.

[0051] Among them, when the second frequency of the second PWM signal PWMb is constant, the smaller the duty cycle of the second PWM signal PWMb is, the higher the reduced power consumption is. Similarly, when the duty cycle of the second PWM signal PWMb is constant, the smaller the second frequency of the second PWM signal PWMb is, the longer the total time that the fill light 120 does not work during the non-exposure period is, the higher the reduced power consumption will be. Compared with the original power consumption generated by the fill light driving circuit 30 and the fill light 120 driven entirely by the first PWM signal PWMa, the power consumption can be reduced by more than 90% through signal modulation.

[0052] In an optional embodiment, in order for the camera 200 to obtain adaptive fill light during the exposure period, the control circuit 10 is further configured as follows:

[0053] Obtaining image grayscale information of the camera 200 and comparing it with a preset image grayscale value;

[0054] When the grayscale value of the image grayscale information is greater than the preset image grayscale value, reducing the duty cycle and / or frequency of the first PWM signal PWMa;

[0055] When the grayscale value of the image grayscale information is less than the preset image grayscale value, increasing the duty cycle and / or frequency of the first PWM signal PWMa;

[0056] When the grayscale value of the image grayscale information is equal to the preset image grayscale value, the duty cycle and frequency of the first PWM signal PWMa are maintained.

[0057] In this embodiment, the control circuit 10 is connected to the camera 200. After the camera 200 obtains the image information of the exposure period in each frame, the control circuit 10 obtains the image grayscale information through the camera 200, thereby determining the current fill light state. When the grayscale value of the obtained image grayscale information is greater than the preset image grayscale value, it is determined that the brightness of the current fill light 120 is too high. At this time, the control circuit 10 reduces the duty cycle and / or frequency of the first PWM signal PWMa. By reducing at least one of the duty cycle and frequency of the first PWM signal PWMa, the current of the fill light driving signal output by the fill light driving circuit 30 can be reduced, thereby reducing the brightness of the fill light 120 and the image grayscale.

[0058] When the grayscale value of the acquired image grayscale information is less than the preset image grayscale value, it is determined that the brightness of the current fill light 120 is too low. At this time, the control circuit 10 increases the duty cycle and / or frequency of the first PWM signal PWMa. By increasing at least one of the duty cycle and frequency of the first PWM signal PWMa, the current of the fill light driving signal output by the fill light driving circuit 30 can be increased, thereby increasing the brightness of the fill light 120 and the image grayscale.

[0059] Similarly, when the grayscale value of the image grayscale information is equal to the preset image grayscale value, it is determined that the brightness of the current fill light 120 matches the current exposure requirement. At this time, the control circuit 10 maintains the duty cycle and frequency of the first PWM signal PWMa without adjustment.

[0060] The size of the preset image grayscale value can be set according to demand. In an optional embodiment, the range of the preset image grayscale value is 200-250.

[0061] The image grayscale information is obtained, and the duty cycle and / or frequency of the first PWM signal PWMa is negatively feedback adjusted according to the grayscale value of the image grayscale information. When the grayscale value of the image grayscale information exceeds the preset image grayscale value, the duty cycle and / or frequency of the first PWM signal PWMa is reduced. When the grayscale value of the image grayscale information is less than the preset image grayscale value, the duty cycle and / or frequency of the first PWM signal PWMa is increased, so that the grayscale value of the image grayscale information after fill light is maintained at the preset image grayscale value, and automatic balance of fill light is achieved, so as to achieve the best exposure effect of the camera 200. The second frequency of the second PWM signal PWMb is fixed in the initial stage and may not be changed during subsequent balance control. The frequency and duty cycle of the first PWM signal PWMa may be adjusted according to the fill light requirement.

[0062] The signal modulation circuit 20 can adopt a structure such as a logic gate or a trigger. In order to simplify the circuit structure, Figure 6 As shown, in an optional embodiment, the signal modulation circuit 20 includes:

[0063] The AND gate AND has an input terminal connected to the signal output terminal of the control circuit 10 . The AND gate AND is configured to receive the first PWM signal PWMa and the second PWM signal PWMb, and output a modulated signal PWMc after the signals are superimposed.

[0064] The output end of the AND gate AND is connected to the control end of the fill light driving circuit 30. The AND gate AND performs signal superposition on the first PWM signal PWMa and the second PWM signal PWMb. When both signals are at a high level, the AND gate AND outputs a high level. When one of the two signals is at a low level, the AND gate AND outputs a low level. By signal superposition, a modulation signal PWMc is generated. During the non-exposure period of the camera 200, that is, when the second PWM signal PWMb is at a low level, the modulation signal PWMc is synchronously modulated to a low level, and the fill light driving circuit 30 stops driving, the fill light 120 remains off, and the camera 200 does not perform fill light operation, thereby reducing the overall power consumption of the camera module 1 and the extended reality device and meeting the low power consumption requirement.

[0065] The fill light driving circuit 30 can adopt a corresponding power conversion circuit, such as a buck-boost circuit, a voltage stabilizing circuit, etc. The power conversion circuit generates a fill light driving signal of corresponding size according to the received modulation signal PWMc, and drives the fill light 120 to light up or turn off, thereby realizing the fill light work during the exposure period.

[0066] In an alternative embodiment, if Figure 3 or Figure 4 As shown, the fill light driving circuit 30 includes:

[0067] The power supply circuit 31 is configured to perform voltage conversion on the input power supply VIN and output a preset working power supply VCC;

[0068] The constant current driving circuit 32 is connected to the power supply circuit 31, the fill light 120 and the signal modulation circuit 20, and is configured to output a constant driving current to the fill light 120 according to the modulation signal PWMc, the output frequency of the driving current is consistent with the output frequency of the modulation signal PWMc, and the duty cycle of the driving current is consistent with the duty cycle of the modulation signal PWMc.

[0069] In this embodiment, Figure 3 As shown, the constant current driving circuit 32 can be connected between the power supply circuit 31 and the fill light 120, or as shown in FIG. Figure 4 As shown, the constant current driving circuit 32 can also be connected to the output end of the fill light 120 , and the input end of the fill light 120 is connected to the output end of the power supply circuit 31 .

[0070] The power supply circuit 31 realizes a corresponding one of the functions of boosting, bucking and stabilizing the voltage, converts the power supply voltage, and outputs a stable working power supply to the fill light 120 and the constant current drive circuit 32, wherein the power supply circuit 31 is connected to the power module in the extended reality device, and the power module can be a battery.

[0071] In order to further reduce power consumption, a power switch is also provided between the power circuit 31 and the power module. When the camera module 1 is started, the power switch is turned on under the triggering of the control circuit 10 and transmits the power supply to the power circuit 31 .

[0072] The control end of the constant current driving circuit 32 constitutes the control end of the fill light driving circuit 30, and receives the modulated modulation signal PWMc. When the camera module 1 starts working, the control circuit 10 synchronously outputs the first PWM signal PWMa and the second PWM signal PWMb. The second PWM signal PWMb is output to the camera 200 to control the camera 200 to perform exposure. At the same time, the modulation signal PWMc is output to the constant current driving circuit 32. The constant current driving circuit 32 adjusts the output frequency and duty cycle of the driving current according to the frequency and duty cycle of the modulation signal PWMc, and realizes constant current control when outputting the driving current, so that the driving current is output constantly, thereby outputting the fill light driving signal of the corresponding frequency and duty cycle to the fill light 120. The fill light driving signal changes in direct proportion to the frequency and duty cycle of the modulation signal PWMc, and is lit during the exposure period of the camera 200 to provide fill light for the camera 200.

[0073] According to the working mode of the power supply circuit 31, the specific structure of the power supply circuit 31 can be set accordingly. In an optional embodiment, the power supply circuit 31 is at least one of a boost circuit and a buck circuit. When the boost circuit and the buck circuit are included, the voltage can be boosted first and then bucked, or the voltage can be bucked first and then boosted. In an optional embodiment, in order to improve the power conversion efficiency, such as Figure 6 As shown, the power supply circuit 31 includes a first electronic switch tube Q1, a diode D0, an inductor L1, a first capacitor C1 and a second capacitor C2;

[0074] The first end of the first electronic switch tube Q1 constitutes the power input end of the power supply circuit 31, the second end of the first electronic switch tube Q1, the cathode of the diode D0 and the first end of the inductor L1 are connected, the control end of the first electronic switch tube Q1 is configured to receive the third PWM signal PWMd, the second end of the inductor L1, the first end of the first capacitor C1 and the first end of the second capacitor C2 are connected to constitute the power output end of the power supply circuit 31, the anode of the diode D0, the second end of the first capacitor C1 and the second end of the second capacitor C2 are grounded.

[0075] In this embodiment, the first electronic switch tube Q1, the diode D0 and the inductor L1 constitute a step-down circuit, which steps down the input power supply. The first electronic switch tube Q1 is turned on and off according to the received third PWM signal PWMd. When the first electronic switch tube Q1 is turned on, the inductor L1 is charged. When the first electronic switch tube Q1 is turned off, the inductor L1, the first capacitor C1, the second capacitor C2 and the diode D0 continue to flow and output the stepped-down working power supply to the fill light 120 and the constant current drive circuit 32. The first capacitor C1 and the second capacitor C2 are used to achieve filtering.

[0076] The constant current driving circuit 32 can adopt a constant current driving chip, a constant current source circuit and the like. Figure 5As shown, in an optional embodiment, the constant current driving circuit 32 includes:

[0077] The constant current source circuit 321 is connected to the output end of the fill light 120 and is configured to output a constant driving current to the fill light 120;

[0078] The current regulation circuit 322 is connected to the constant current source circuit 321 and the signal modulation circuit, and is configured to adjust the output state of the constant current source circuit 321 according to the modulation signal PWMc so that the output frequency of the driving current is consistent with the output frequency of the modulation signal PWMc, and the duty cycle of the driving current is consistent with the duty cycle of the modulation signal PWMc.

[0079] In this embodiment, when the current regulation circuit 322 is not set, the constant current source circuit 321 collects the current flowing through the fill light 120 and compares it with the set reference current to achieve negative feedback regulation, thereby achieving constant current output. When the current regulation circuit 322 is set, the current regulation circuit 322 adjusts the output frequency and duty cycle of the output current of the constant current source circuit 321 according to the received modulation signal PWMc, so that the frequency and duty cycle of the driving current are the same as the frequency and duty cycle of the modulation signal PWMc, thereby achieving the purpose of reducing power consumption.

[0080] Among them, the constant current source circuit 321 can be composed of a negative feedback circuit, a sampling circuit, etc., and the current regulation circuit 322 can be composed of a control chip, a switch circuit, etc. Figure 6 As shown, in an optional embodiment, the constant current source circuit 321 includes a second electronic switch tube Q2, an operational amplifier U1, a voltage source U2 and a resistor R1;

[0081] The first end of the second electronic switch tube Q2 is connected to the output end of the fill light 120, the second end of the second electronic switch tube Q2 is connected to the first end of the resistor R1, the first end of the resistor R1 is also connected to the inverting input end of the operational amplifier U1, the second end of the resistor R1 is grounded, the power supply end of the voltage source U2 is connected to the non-inverting input end of the operational amplifier U1, and the output end of the operational amplifier U1 is connected to the control end of the second electronic switch tube Q2 through the current regulating circuit 322.

[0082] The current regulating circuit 322 includes a third electronic switch tube SW;

[0083] A first end of the third electronic switch tube SW is connected to the output end of the operational amplifier U1 , and a second end of the third electronic switch tube SW is connected to the control end of the second electronic switch tube Q2 .

[0084] In this embodiment, the second electronic switch tube Q2 is an NMOS tube. The second electronic switch tube Q2, the voltage source U2, the operational amplifier U1 and the resistor R1 form a constant current source circuit 321. The resistor R1 constitutes a sampling resistor, and the ratio of its terminal voltage to the resistor R1 is the current value of the driving current. When the third electronic switch tube SW remains in the on state, assuming that there is a voltage Vref on the resistor R1, the current flowing through the drain of the second electronic switch tube Q2 is Id=V0 / r1, V0 is the voltage value of the voltage source U2, and r1 is the resistance value of the resistor R1. Since the second electronic switch tube Q2 is fully turned on, the current of the source of the second electronic switch tube Q2 is approximately equal to the drain current, that is, the current flowing through the fill light 120 is Vref / r1. Vref is connected to the inverting input terminal of the operational amplifier U1 through negative feedback. According to the virtual short principle of the operational amplifier U1, V0=Vref, so that the voltage of the resistor R1 is stable, thereby achieving a stable driving current Id.

[0085] At the same time, when the third electronic switch tube SW in the current regulation circuit 322 is set, the control end of the third electronic switch tube SW is connected to the output end of the signal modulation circuit 20 and receives the modulation signal PWMc. The third electronic switch tube SW is turned on and off according to the frequency and duty cycle of the modulation signal PWMc. The path state from the operational amplifier U1 to the second electronic switch tube Q2 is determined by the on-off state of the third electronic switch tube SW, so that the frequency and duty cycle of the output current of the second electronic switch tube Q2 change with the frequency and duty cycle of the modulation signal PWMc, thereby achieving the purpose of reducing power consumption.

[0086] Among them, Figure 6 and Figure 7 As shown, assuming that the voltage value fed back by the resistor R1 is 0.2V, when the duty cycle of the control signal of the third electronic switch tube SW is 100%, the current of the second electronic switch tube Q2 and the fill light 120 is I=Vref / R1, assuming that R1=0.6Ω, then I=333mA, assuming that the fill light 120 includes 8 lamp beads, each of which has a conduction voltage of 1.9V, and the voltage of the 8 lamp beads is 1.9V*8=15.2V. The power consumption of all the lamp beads is P1=V*I=5.22W. This current is very large. If it is not controlled, the LED lamp beads and the second electronic switch tube Q2 will be at risk of burning out.

[0087] When the duty cycle of the control signal of the third electronic switch tube SW is 50%, the average value of the voltage across the lamp bead is Vave=0.5Vled, the average current is I=0.5Ir1, and the power consumption of the entire lamp bead is P2=Vave*I=0.25P1=1.305W. As the duty cycle decreases, the power consumption of the entire lamp bead will continue to decrease.

[0088] like Figure 8As shown, assuming that the period of the second PWM signal PWMb is T2, and the duty cycle is D, after signal modulation, in the duty cycle D, the output period of the first PWM signal PWMa is T1, and the duty cycle is D1. In the entire period of the modulation signal PWMc, the voltage effective value U2=D1*D2*Vled, the current effective value I1=D1*D2*Ir1, therefore, the power of the lamp bead is P1=D12*D22Vled*Ir1=5.22D12*D22, if the duty cycle of D1 is 50%, and the duty cycle of D2 is 10%, the power consumption of the LED of the entire circuit is P1=0.0131W, which is 99% lower than the power consumption under the drive of the first PWM signal PWMa alone. In this case, LED lamp beads with higher power and brightness can be selected to enhance the brightness without considering power consumption and heat dissipation.

[0089] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: the above-mentioned fill light control circuit 110 is composed of a control circuit 10, a signal modulation circuit 20 and a fill light driving circuit 30, the control circuit 10 outputs a first PWM signal PWMa and a second PWM signal PWMb of a first frequency and a second frequency respectively, the second PWM signal PWMb drives the camera 200 to expose, the first PWM signal PWMa and the second PWM signal PWMb are output to the fill light driving circuit 30 after signal superposition modulation, thereby outputting a fill light driving signal of corresponding size to the fill light 120, through signal superposition modulation, the fill light 120 performs fill light work during the exposure period of the camera 200, and does not perform fill light work during the non-exposure period of the camera 200, thereby reducing the overall power consumption of the camera module 1 and the extended reality device.

[0090] The present invention further proposes a camera module 1 of an extended reality device, which includes a camera 200, a fill light 120 and a fill light control circuit 110 of the extended reality device. The specific structure of the fill light control circuit 110 of the extended reality device refers to the above embodiment. Since the camera module 1 of the extended reality device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here one by one.

[0091] like Figure 1 As shown, the fill light driving circuit 30 is connected to the camera 200 and the fill light 120 respectively. The fill light driving circuit 30 outputs the second PWM signal PWMb to the camera 200 to control the exposure of the camera 200. At the same time, the fill light driving circuit 30 outputs the fill light driving signal corresponding to the modulation signal PWMc to the fill light 120, thereby driving the fill light 120 to light up the fill light when the camera 200 is exposed, thereby reducing the overall power consumption of the camera module 1 and the extended reality device.

[0092] The present invention further proposes an extended reality device, which includes a camera module 1. The specific structure of the camera module 1 refers to the above embodiment. Since the extended reality device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here one by one.

[0093] The extended reality device may be an AR device, a VR device, an MR device, etc. The extended reality device may be head-mounted, such as a helmet, glasses, etc., such as AR medical glasses.

[0094] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A fill light control circuit for an extended reality device, It is characterized in that Used to control a fill light (120) to provide fill light for a camera (200), the fill light control circuit comprising: A control circuit (10) configured to output a first PWM signal (PWMa) of a first frequency and a second PWM signal (PWMb) of a second frequency, wherein the second PWM signal (PWMb) is an exposure control signal of the camera (200), and the first frequency is greater than the second frequency; A signal modulation circuit (20) connected to the control circuit (10) and configured to perform signal superposition on the first PWM signal (PWMa) and the second PWM signal (PWMb) to output a modulation signal (PWMc); The fill light driving circuit (30) is connected to the signal modulation circuit (20) and the fill light (120), and is configured to generate a fill light driving signal according to the modulation signal (PWMc) to drive the fill light (120) to perform fill light operation.

2. The fill light control circuit of the extended reality device according to claim 1, It is characterized in that The control circuit (10) is further configured to: Acquiring image grayscale information of the camera (200), and comparing it with a preset image grayscale value; When the grayscale value of the image grayscale information is greater than the preset image grayscale value, reducing the duty cycle and / or frequency of the first PWM signal (PWMa); When the grayscale value of the image grayscale information is less than the preset image grayscale value, increasing the duty cycle and / or frequency of the first PWM signal (PWMa); When the grayscale value of the image grayscale information is equal to the preset image grayscale value, the duty cycle and frequency of the first PWM signal (PWMa) are maintained.

3. The fill light control circuit of the extended reality device according to claim 1, It is characterized in that The fill light driving circuit (30) comprises: A power supply circuit (31) is configured to convert an input power supply (VIN) into a voltage so as to output a working power supply (VCC) of a preset magnitude; A constant current drive circuit (32) is connected to the power supply circuit (31), the fill light (120) and the signal modulation circuit (20), and is configured to output a constant drive current to the fill light (120) according to the modulation signal (PWMc), wherein the output frequency of the drive current is consistent with the output frequency of the modulation signal (PWMc), and the duty cycle of the drive current is consistent with the duty cycle of the modulation signal (PWMc).

4. The fill light control circuit of the extended reality device as claimed in claim 3, It is characterized in that The power supply circuit (31) comprises a voltage-boosting circuit or a voltage-dropping circuit.

5. The fill light control circuit of the extended reality device as claimed in claim 3, It is characterized in that The constant current driving circuit (32) comprises: A constant current source circuit (321), connected to the output end of the fill light (120), and configured to output a constant driving current to the fill light (120); The current regulating circuit (322) is connected to the constant current source circuit (321) and the signal modulation circuit (20), and is configured to adjust the output state of the constant current source circuit (321) according to the modulation signal (PWMc) so that the output frequency of the drive current is consistent with the output frequency of the modulation signal (PWMc), and the duty cycle of the drive current is consistent with the duty cycle of the modulation signal (PWMc).

6. The fill light control circuit of the extended reality device as claimed in claim 5, It is characterized in that The constant current source circuit (321) comprises a second electronic switch tube (Q2), an operational amplifier (U1), a voltage source (U2) and a resistor (R1); The first end of the second electronic switch tube (Q2) is connected to the output end of the fill light (120), the second end of the second electronic switch tube (Q2) is connected to the first end of the resistor (R1), the first end of the resistor (R1) is also connected to the inverting input end of the operational amplifier (U1), the second end of the resistor (R1) is grounded, the power supply end of the voltage source (U2) is connected to the non-inverting input end of the operational amplifier (U1), and the output end of the operational amplifier (U1) is connected to the control end of the second electronic switch tube (Q2) through the current regulating circuit.

7. The fill light control circuit of the extended reality device according to claim 6, It is characterized in that The current regulating circuit (322) comprises a third electronic switch tube (SW); The first end of the third electronic switch tube (SW) is connected to the output end of the operational amplifier (U1), and the second end of the third electronic switch tube (SW) is connected to the control end of the second electronic switch tube (Q2).

8. The fill light control circuit of the extended reality device according to claim 1, It is characterized in that The signal modulation circuit (20) comprises: An AND gate (AND), wherein an input end of the AND gate (AND) is connected to a signal output end of the control circuit (10), and the AND gate (AND) is configured to receive the first PWM signal (PWMa) and the second PWM signal (PWMb) to output the modulated signal (PWMc).

9. A camera module for an extended reality device, It is characterized in that The device comprises a camera (200), a fill light (120), and a fill light control circuit of the extended reality device according to any one of claims 1 to 8.

10. An extended reality device, It is characterized in that A camera module (1) comprising the extended reality device as claimed in claim 9.

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