Laser projection equipment and control method thereof

Abstract

According to the laser projection equipment and the control method thereof, the laser projection equipment comprises a laser light source, a light modulation device, a projection lens, a display control module, a power panel, a laser driving module and a protection module, and the power panel provides voltage for the laser driving module to form a power supply path; the laser driving module is arranged between the display control module and the laser and is used for outputting a state signal of a first state when the current flowing through the laser is detected to be greater than a first threshold value; the protection module is connected with the laser driving module and the power panel and is used for entering a protection mode when receiving the control signal of the first state and continuously outputting a protection signal to the power panel in the protection mode until the protection mode is quitted; the protection signal is used for enabling the power panel to stop outputting voltage to the laser driving module to form a power supply circuit break. According to the invention, the laser in the laser projection equipment can be protected.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a laser projection device and a control method thereof. Background Art

[0002] Laser projection equipment uses digital light processing (DLP) technology to digitally process the image signal before projecting the light. It has the characteristics of bright colors, high brightness, and flexible screen size, and has been widely used. Usually, laser projection equipment includes a power supply module and a laser. The power supply module is used to supply power to the laser to drive the laser to emit light. The laser projection equipment focuses the laser light into an image.

[0003] In actual applications, in some fault scenarios such as overpower or short circuit of the power supply module, the voltage at the output end of the laser driver module is too high, which makes the working voltage applied to the laser too high, thus damaging the laser and thus affecting the life of the laser TV. Therefore, it is important to provide a laser projection device with the function of protecting the laser. Summary of the invention

[0004] The present application provides a laser projection device and a control method thereof, so as to protect the laser.

[0005] In a first aspect, the present application provides a laser projection device, comprising: a laser light source, a light modulation device, a projection lens, a display control module, a power supply board, a laser driving module and a protection module, wherein the power supply board provides voltage to the laser driving module to form a power supply path; the laser light source comprises a laser for emitting a laser beam to provide an illumination beam for the device; the display control module is used to output a laser driving signal and an image display driving signal for driving the light modulation device; the light modulation device modulates the laser beam under the drive of the image display driving signal; the projection lens is used to receive the modulated laser beam and project an image; the laser driving module is arranged at The display control module is between the laser and is used to receive the laser driving signal to drive the laser to emit light or extinguish; and when it is detected that the current flowing through the laser is greater than the first threshold, the state signal of the first state is output, and when it is detected that the current flowing through the laser is not greater than the first threshold, the state signal of the second state is output; the protection module is connected to the laser driving module and the power board, and is used to enter the protection mode when receiving the control signal of the first state, and in the protection mode, continuously output the protection signal to the power board until the protection mode is exited; the protection signal is used to stop the power board from outputting voltage to the laser driving module, forming a power supply circuit.

[0006] In some embodiments, the protection module also receives a first power supply input signal, and the protection module is used to continuously output the protection signal in a protection mode based on the first power supply input signal, and exit the protection mode when the first power supply input signal is disconnected.

[0007] In some embodiments, the protection module includes: a judgment unit and a signal generating unit; the judgment unit is connected to the laser driving module and the signal generating unit, and is used to enter a protection mode when receiving a control signal of a first state, and continuously output a first level to the signal generating unit in the protection mode; the signal generating unit is connected to the power board, and is used to output the protection signal to the power board when receiving a first voltage.

[0008] In some embodiments, the power board includes: a first controller and a power supply unit, the first controller is connected to the power supply unit and is used to output a first drive signal to the power supply unit; the power supply unit is connected to the laser driving module and receives a second power supply input signal, and the power supply unit is used to supply power to the laser driving module based on the second power supply input signal and under the control of the first driving signal.

[0009] In some embodiments, the signal generating unit is connected to the enable pin of the first controller, and is used to output the protection signal to the enable pin of the first controller when receiving the first level, and the protection signal is used to pull down or raise the voltage of the enable pin of the first controller so that the voltage of the enable pin of the first controller is an inactivation voltage.

[0010] In some embodiments, the first drive signal is a PWM signal; the signal generating unit is connected to the output end of the first controller, and is used to output the protection signal to the output end of the first controller when receiving the first level, and the protection signal is used to lower or raise the voltage of the output end of the first controller so that the power supply unit receives a constant level signal.

[0011] In some embodiments, the judgment unit includes: a first resistor, a second resistor, a third resistor, a first switch tube and a second switch tube; one end of the first resistor receives a second power supply input signal, the other end of the first resistor is connected to one end of the second resistor, and the other end of the second resistor is connected to one end of the first switch tube; the other end of the first switch tube is grounded, the control end of the first switch tube is connected to the laser driving module, and the first switch tube is turned on when the laser driving module outputs a state signal of a first state; one end of the second switch tube is connected to one end of the first resistor and receives the second power supply input signal, the other end of the second switch tube is connected to one end of the third resistor and is connected to the signal generating unit as an output end, the control end of the second switch tube is connected to the other end of the first resistor and one end of the second resistor; the other end of the third resistor is connected to the control end of the first switch tube.

[0012] In some embodiments, the judgment unit also includes: a fifth resistor, a sixth resistor, a fourth switch tube and a photoelectric coupler, one end of the four switch tubes is connected to the secondary output end of the photoelectric coupler, the other end of the four switch tubes is grounded, the control end of the four switch tubes is connected to the laser driving module, the fourth switch tube is turned on when receiving the state signal of the first state, and is disconnected when receiving the state signal of the second state; the secondary input end of the photoelectric coupler is connected to the other end of the sixth resistor, the secondary input end of the photoelectric coupler is connected to the other end of the fifth resistor, and the secondary output end of the photoelectric coupler is connected to the control end of the first switch tube; one end of the fifth resistor receives a third power supply input signal; one end of the sixth resistor receives the third power supply input signal.

[0013] In some embodiments, the signal generating unit includes: a third switch tube and a fourth resistor; one end of the third switch tube is connected to the enable pin of the first controller, the other end of the third switch tube is connected to one end of the fourth resistor, the control end of the third switch tube is connected to the output end of the judgment unit, the third switch tube is turned on when receiving the first level, and is turned off when not receiving the first level; the other end of the fourth resistor is grounded.

[0014] In some embodiments, the signal generating unit includes: a first diode, a third switch tube and a fourth resistor, the anode of the first diode is connected to the output end of the first controller, the cathode of the first diode is connected to one end of the third switch tube; the other end of the third switch tube is connected to one end of the fourth resistor, the control end of the third switch tube is connected to the output end of the judgment unit, the third switch tube is turned on when receiving the first level, and is turned off when not receiving the first level; the other end of the fourth resistor is grounded.

[0015] In a second aspect, the present application provides a control method for a laser projection device, the laser projection device comprising: a display control module, a power board, a laser driving module and a protection module, the method comprising: the laser driving module receiving a laser driving signal output by the display control module to drive the laser to emit light or extinguish; and outputting a state signal of a first state when detecting that the current flowing through the laser is greater than a first threshold value, and outputting a state signal of a second state when detecting that the current flowing through the laser is not greater than the first threshold value; the laser driving module is connected to the power board, and forms a power supply path with the power supply based on the voltage provided by the power board; the protection module enters a protection mode when receiving a control signal of the first state, and in the protection mode, continuously outputs a protection signal to the power board until exiting the protection mode; the protection signal is used to cause the power board to stop outputting voltage to the laser driving module, forming a power supply circuit.

[0016] In the laser projection device and control method provided by the present embodiment, the power board provides voltage to the laser driving module to form a power supply path. The laser driving module drives the laser to emit light or extinguish based on the laser driving signal output by the received display control module. When the current flowing through the laser is detected to be greater than the first threshold, the state signal of the first state is output. When the current flowing through the laser is detected to be not greater than the first threshold, the state signal of the second state is output; the protection module is connected to the laser driving module and the power board, and enters the protection mode when receiving the state signal of the first state. In the protection mode, the protection circuit continuously outputs the protection signal to the power board until the protection mode is exited. The protection signal causes the power board to stop outputting voltage to the laser driving module, forming a power supply circuit. In this scheme, when the state signal of the protection module is in the first state, the protection module enters the protection mode and continuously outputs the protection signal to the signal generating unit. Since the protection module enters the self-locking state in the protection mode, the output of the protection signal will not be affected by the state signal, so that the circuit between the power board and the laser is continuously maintained, thereby avoiding repeated overvoltage of the laser, thereby protecting the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings herein are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the embodiments of the present application, and together with the description are used to explain the principles of the embodiments of the present application.

[0018] The above drawings have shown clear embodiments of the embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the embodiments of the present application in any way, but to illustrate the concepts of the embodiments of the present application for those skilled in the art by referring to specific embodiments.

[0019] Figure 1 is a schematic diagram of a laser projection device provided in an embodiment of the present application;

[0020] Figure 2 A schematic diagram of a circuit structure of a laser projection device according to an embodiment;

[0021] Figure 3 A schematic diagram of the structure of a laser projection device provided in one embodiment of the present application;

[0022] Figure 4 A schematic diagram of the structure of another laser projection device provided in one embodiment of the present application;

[0023] Figure 5 A schematic diagram of the structure of another laser projection device provided in an embodiment of the present application;

[0024] Figure 6 A schematic structural diagram of a laser projection device provided in another embodiment of the present application;

[0025] Figure 7 A schematic diagram of the structure of another laser projection device provided in another embodiment of the present application;

[0026] Figure 8 A schematic structural diagram of another laser projection device provided in another embodiment of the present application;

[0027] Fig. 9 This is a schematic structural diagram of a laser projection device provided in another embodiment of the present application;

[0028] Fig.10 This is a schematic diagram of the structure of a protection module in an example;

[0029] Fig.11 is a structural schematic diagram of a protection module in another example;

[0030] Fig.12 is a structural schematic diagram of a protection module in another example;

[0031] Fig.13 This is a schematic structural diagram of another laser projection device provided in yet another embodiment of the present application;

[0032] Fig.14 is a structural schematic diagram of a protection module in another example;

[0033] Fig.15 This is a schematic structural diagram of another laser projection device provided in another embodiment of the present application;

[0034] Fig.16 is a structural schematic diagram of a protection module in another example;

[0035] Fig.17 This is a schematic structural diagram of another laser projection device provided in another embodiment of the present application;

[0036] Fig.18 FIG. 4 is a timing diagram of an input signal of a laser projection device in an example.

[0037] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0038] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0039] It should be noted that the brief description of terms in this application is only for the convenience of understanding the embodiments described below, and is not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their ordinary and common meanings.

[0040] The terms "first", "second", etc. in the specification and claims of this application and the above drawings are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise indicated. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, for example, they can be implemented in an order other than those given in the diagrams or descriptions of the embodiments of this application.

[0041] In addition, the terms "including" and "having" and any variations thereof are intended to cover but not exclude inclusion, for example, a product or device comprising a list of components is not necessarily limited to those components explicitly listed, but may include other components not explicitly listed or inherent to such products or devices. The term "circuitry" as used in this application refers to any known or later developed hardware, software, firmware, artificial intelligence, fuzzy logic, or combination of hardware and / or software code that is capable of performing the functions associated with the element.

[0042] Explanation of the terms involved in this application:

[0043] PFC (Power Factor Correction): Power factor correction, power factor refers to the relationship between effective power and total power consumption (apparent power), that is, the ratio of effective power to total power consumption (apparent power). The basic operating principle of PFC voltage-stabilized switching power supply is to use inductor compensation method to adjust the input current waveform to make it as similar as possible to the input voltage waveform, and the power factor correction value approaches 100%.

[0044] LLC: A resonant circuit that achieves a constant output voltage by controlling the switching frequency (frequency regulation). When a single-port network containing inductors, capacitors, and resistors has the same phase as the port voltage and current waveforms at certain operating frequencies, the circuit is said to resonate. A circuit that can resonate is called a resonant circuit.

[0045] Rectifier bridge circuit: It is the most widely used rectifier circuit in power circuits. It consists of 4 diodes with the same direction and a transformer. Rectification is the process of converting AC into DC. Using devices with unidirectional conductive properties, AC with changed direction and magnitude can be converted into DC.

[0046] The following is an exemplary description of the architecture and imaging principle of the laser projection device.

[0047] Figure 1 Schematic diagram of a laser projection device provided in an embodiment of the present application. Figure 1 As shown, after the upper shell of the laser projection device is disassembled, the internal structure is divided according to the optical function, and may include a light source 100, an optical machine 200, and a lens 300, wherein the light source 100 is used to provide a light source illumination beam, which is transmitted to the rear-end optical modulation device and the projection lens. The light source 100 may include a laser of at least one color, such as a blue laser, or a two-color laser, such as a blue laser and a red laser, or a three-color laser light source, including red, green, and blue lasers, for providing a three-color laser illumination beam.

[0048] The laser beam provided by the light source 100 enters the illumination optical path of the optical machine 200 after light combination and shaping. In the DLP projection architecture, the DMD chip is the core optical modulation device. The DMD chip receives the driving control signal corresponding to the image signal, and flips the thousands of tiny mirrors on its surface to the positive or negative angle corresponding to the driving signal, and reflects the light beam irradiating its surface into the lens 300.

[0049] The lens 300 may be an ultra-short-throw projection lens, and the ultra-short-throw projection lens 300 is used to project an image beam onto a projection screen, thereby realizing projection image display. The laser projection device in the above example may be an ultra-short-throw laser projection device.

[0050] Based on the above Figure 1 Example laser projection device structure, Figure 2 A schematic diagram of a circuit architecture of a laser projection device according to an embodiment is shown.

[0051] like Figure 2 As shown, the laser projection device includes: a display panel 001, a power panel 10, and a TV panel 003. Among them, the power panel 10 is connected to the display panel 001 and the TV panel 003 respectively, and can be used to power various devices or partial modules on the display panel 001 and the TV panel 003. At the same time, it can also power other functional modules in the laser projection device, such as the human eye protection module, the fan, the WIFI module, etc., to ensure the normal power supply of various parts of the laser projection device. In some specific implementations, a laser driving module can also be provided on the power panel 10. Alternatively, the laser driving module can also be provided independently of the power panel 10.

[0052] TV board 003 is mainly used for decoding external audio and video signals and outputting video image signals.

[0053] The TV panel 003 is provided with a system on chip (SoC), which can decode data in different data formats into a normalized format, and transmit the data in the normalized format to the display panel 001 through, for example, a connector.

[0054] The video image signal output by the TV panel 003 is transmitted to the display panel 001 .

[0055] The display panel 001 may be provided with a Field Programmable Gate Array (FPGA) and an algorithm processing module FPGA, which are used to process the input video image signal, such as performing MEMC frequency multiplication processing, or image correction, etc. to realize the image enhancement function. The display control module 20 is connected to the algorithm processing module FPGA, and is used to receive the processed video image processing signal data as the image data to be displayed. It should be noted that FPGA usually exists as an enhancement function module. In some low-cost solutions, this module part may not be provided, and the display control module 20 receives the video image display signal output by the TV panel 003.

[0056] The display panel 001 is used to generate an initial driving signal for driving the laser and an image display driving signal for driving the light modulation device.

[0057] The display control module 20 mainly includes a digital light processing chip (Digital Light Processing, DLP), and may also include a driving chip.

[0058] In the DLP control architecture, the light source part needs to cooperate with the working timing of the DLP chip and the DMD chip. Specifically, the DLP chip outputs an image enable signal, which can also be called a primary color light enable signal, usually expressed as X_EN, where X is the abbreviation of different primary color lights, and also outputs a dimming signal, referred to as a PWM signal. Along with the DMD chip's sequential modulation process of different primary color image components, the light source part needs to synchronously output the primary color light beams of the corresponding colors. That is, the DLP chip outputs a primary color light enable signal to notify the laser light source to enable the lighting of a certain color laser, and outputs a PWM signal to notify a certain laser in the laser light source to light up at what brightness.

[0059] Corresponds to Figure 2 As shown, the display control module 20 is used to generate an image display driving signal for driving the light modulator 50 according to the image signal to be displayed. On the other hand, since the display of the projection image requires the synchronous coordination of the light source light beam and the light modulator, the display control module 20 also generates a driving signal for driving the light source to emit light. The driving signal may include an initial image enable signal EN and an initial current control signal, such as a current PWM signal, wherein the initial image enable signal EN is a timing control signal for coordinating the timing of light outputs of different colors, and the current PWM signal is a periodic square wave signal for providing a current signal for lighting the laser.

[0060] as well as, Figure 2 The circuit architecture diagram of the laser projection device shown also includes a laser driving module 30 for receiving the image enable signal EN and the current PWM signal output by the display control module 20 , as well as receiving the power signal of the power board, and directly controlling the lighting of the laser 040 .

[0061] In the figure, the laser 040 can be a laser of one color or a laser of multiple colors. Usually, a corresponding laser driving module 30 is provided for each color of the laser.

[0062] In some examples, the laser driver module is a DC-DC conversion circuit, specifically a step-down circuit, which is used to convert the high-voltage supply voltage into a lower voltage suitable for the laser. However, in some fault scenarios, such as when the laser driver module is short-circuited or overpowered, the voltage at the output end of the laser driver module is too high, making the operating voltage applied to the laser too high, which will damage the laser and affect the life of the laser TV.

[0063] Therefore, it is important to provide a laser projection device having a function of protecting the laser.

[0064] In some examples, the projection device is provided with a protection module, which is connected to the laser driving module and the power board. When the protection module detects that the power supply signal of the laser is greater than a first threshold value, the protection module sends a fault signal to the power board, so that the power board reduces the output power signal based on the fault signal, thereby reducing the voltage applied to both ends of the laser. However, when the protection module detects that the power supply signal of the laser circuit is not greater than the first threshold value, it stops outputting the fault signal. At this time, the power board will raise the output power signal again, and the power supply signal applied to the laser will become high again. This repeated process will still cause damage to the laser.

[0065] To this end, the present application provides a laser projection device, in which a laser driving module is connected to a power board and a protection module. When the laser driving module detects that the output voltage of the laser driving module reaches a first threshold, the laser driving module outputs a status signal of a first state to the protection module. When receiving the first status signal, the protection module enters a protection mode and continuously outputs a protection signal to the power board. After the power board receives the protection signal, the power supply path between the power board and the laser driving module is disconnected. In the protection mode, the protection module enters a self-locking state, and the output of the protection signal will not be affected by the status signal. In this way, the circuit between the power board and the laser is continuously kept open, thereby avoiding repeated overvoltage of the laser, thereby achieving protection of the laser.

[0066] The technical solutions of the present application and the technical solutions of the present application are described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. In the description of the present application, unless otherwise clearly specified and limited, each term should be understood in a broad sense in the art. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0067] Figure 3 This is a schematic diagram of the structure of a laser projection device provided in one embodiment of the present application. Figure 3 FIG. 1 shows a partial circuit of the laser projection device, and other circuits not related to the present application are not shown. Figure 3 As shown, the laser projection device provided by the present application includes: a laser light source, a light modulation device 50, a projection lens 60, a display control module 20, a power board 10, a laser driving module 30 and a protection module 70.

[0068] The power board 10 provides voltage to the laser driving module 30 to form a power supply path;

[0069] The laser light source includes a laser 40 for emitting a laser beam to provide an illumination beam for the device;

[0070] A display control module 20, used to output a laser driving signal and an image display driving signal for driving the light modulation device 50;

[0071] The light modulator 50 modulates the laser beam under the drive of the image display drive signal;

[0072] A projection lens 60, used to receive the modulated laser beam and project an image;

[0073] The laser driving module 30 is disposed between the display control module 20 and the laser 40, and is used to receive a laser driving signal to drive the laser 40 to emit light or extinguish; and when it is detected that the current flowing through the laser 40 is greater than the first threshold, it outputs a state signal of a first state, and when it is detected that the current flowing through the laser 40 is not greater than the first threshold, it outputs a state signal of a second state;

[0074] The protection module 70 is connected to the laser driving module 30 and the power board 10, and is used to enter the protection mode when receiving the control signal of the first state, and continuously output the protection signal to the power board 10 in the protection mode until exiting the protection mode; the protection signal is used to make the power board 10 stop outputting voltage to the laser driving module 30, forming a power supply circuit.

[0075] In this embodiment, the display control module 20 , the light modulation device 50 , the projection lens 60 and the laser 40 can refer to the above-mentioned example description, which will not be described in detail here.

[0076] The power board 10 can receive AC power, filter and transform the AC power, and then output it to the laser driving module 30 . The laser driving module 30 outputs a power supply voltage to the laser 40 based on the laser driving signal output by the display control module 20 to drive the laser 40 .

[0077] In some examples, Figure 4 This is a schematic diagram of the structure of another laser projection device provided in one embodiment of the present application, in order to focus on describing the important improved parts. Figure 4 Components such as the light modulation device 50 and the projection lens 60 are not shown. Figure 4 As shown, the power board 10 may include a bridge rectifier circuit 13 and a power conversion circuit, wherein the power conversion circuit may include a PFC 14 and an LLC circuit 15. The rectifier bridge circuit 11 receives the AC power, rectifies and filters the AC power, and then outputs it to the PFC circuit 14 and the LLC circuit 15, and performs power conversion through the PFC circuit 14 and the LLC circuit 15 to output a DC voltage to the laser driving module 30. A power supply path is formed between the power board 10 and the laser driving module 30 to supply power to the laser 40.

[0078] As an example, Figure 5 A schematic diagram of the structure of another laser projection device provided in an embodiment of the present application is shown in FIG. Figure 5As shown, the power board 10 includes a first controller 12 and a power supply unit 11.

[0079] The first controller 12 is used to provide a first driving signal;

[0080] A first controller 12, connected to the power supply unit 11, and configured to output a first driving signal to the power supply unit 11;

[0081] The power supply unit 11 is connected to the laser driving module 30 and receives a second power supply input signal. The power supply unit 11 is used to supply power to the laser driving module 30 based on the second power supply input signal and under the control of the first driving signal.

[0082] Combination Figure 4 Example, this example can be regarded as an example scheme of LLC circuit 13. The first controller 12 can be a micro control unit (Micro Control Unit, referred to as MCU), or other processing chips with processing capabilities. Exemplarily, the first controller 12 can receive a feedback signal of the power supply signal, and compare the feedback signal with a preset reference signal, and adjust the corresponding output first drive signal based on the comparison result, so that the power supply unit 11 adjusts the output power supply signal based on the first drive signal, thereby ensuring the stability of the output voltage. In the example where the above-mentioned power board includes a PFC circuit, the second power supply input signal VIN can be output by the PFC circuit.

[0083] Figure 6 A schematic diagram of the structure of a laser projection device provided in another embodiment of the present application is shown in FIG. Figure 6 As shown, the power supply unit 11 may include: a fifth switch tube V5, a sixth switch tube V6, a first inductor L1, a first capacitor C1, a transformer T1 and at least one second diode VD2 / VD3.

[0084] When working, the first controller 12 outputs two first drive signals to the control end of the fifth switch tube V5 and the control end of the sixth switch tube V6 respectively. The first drive signal is a PWM signal. Based on the PWM signal, the fifth switch tube V5 and the sixth switch tube V6 are driven to be turned on and off, thereby controlling the charge and discharge of the first inductor L1. By controlling the duration of the fifth switch tube V5 and the sixth switch tube V6 being turned on and off, the charge and discharge amount of the first inductor L1 is controlled, thereby realizing the control of the output voltage. The second power supply input signal VIN can be Figure 4 The output voltage of the PFC in the example. When the fifth switch tube V5 in the power supply unit 11 fails to receive the first drive signal Drv1 / Drv2, it stops outputting the power supply voltage.

[0085] The laser driving module 30 in this example is a DC-DC conversion circuit, which can be specifically a boost circuit. The laser driving module 30 can be connected to the display control circuit, and based on the dimming signal in the laser driving signal output by the display control circuit, the reference voltage corresponding to the dimming signal is determined, and an output voltage equal to the reference voltage is output, thereby realizing brightness control of the laser 40.

[0086] In addition, the laser driving module 30 is also used to detect the current flowing through the laser 40, and when the current is greater than the first threshold, the state signal of the first state is output, and when the current is not greater than the first threshold, the state signal of the second state is output. The first threshold is the current exceeding the normal working state of the laser 40, which is specifically set based on the power of the laser 40. It can be understood that when the laser 40 outputs the state signal of the first state, it indicates that there is a power supply problem in the current laser 40. As an example, the state signal of the first state and the state signal of the second state can be distinguished by high and low levels, such as the first state signal can be a low level, the second state can be a high level signal, and vice versa.

[0087] Alternatively, the state signal of the first state may be a high level or low level state, and the corresponding state signal of the second state may be a floating signal. In other words, as long as the signal can distinguish between the two states, the present application does not impose any limitation on this.

[0088] In some examples, Figure 7 A schematic diagram of the structure of another laser projection device provided in another embodiment of the present application is shown in FIG. Figure 7 As shown, the laser driving module 30 may include: a second controller 32, a driving unit 31;

[0089] The input end of the driving unit 31 is connected to the power board 10, the output end of the driving unit 31 is connected to the laser 40, the control end of the driving unit 31 is connected to the second controller 32, and receives the second driving signal provided by the second controller 32. The driving unit 31 is used to generate a power supply signal based on the power signal and driven by the second driving signal;

[0090] The second controller 32 receives feedback signals of the dimming signal and the power supply signal. The second controller 32 generates a second driving signal based on the feedback signals of the dimming signal and the power supply signal; and when the current of the laser 40 is greater than the first threshold, the second controller 32 outputs a state signal of the first state, and when the current of the laser 40 is not greater than the first threshold, the second controller 32 outputs a state signal of the second state.

[0091] The second controller 32 may be an MCU or other processing chip with computing and processing functions, and has a working principle similar to that of the first controller 12. Exemplarily, the second controller 32 obtains a reference voltage corresponding to the current dimming signal based on the corresponding relationship between the dimming signal and the reference voltage, compares the sampled feedback signal with the reference voltage, and outputs a corresponding second driving signal based on the comparison result, so that the driving unit 31 adjusts the output power supply signal based on the second driving signal so that the power supply signal reaches the reference voltage, thereby realizing brightness control of the laser 40.

[0092] The second controller 32 is provided with a status pin. Exemplarily, the status pin can be connected to an open-drain circuit provided inside the second controller 32. The open-drain circuit includes a switch tube, one end of which is connected to the status pin, and the other end of the switch tube is grounded. The control end of the switch tube receives a control signal from the second controller 32. When the current of the laser 40 is greater than the first threshold value, the second controller 32 controls the switch tube to turn on, the status pin is grounded, and a low level is output. When the current of the laser 40 is not greater than the first threshold value, the switch in the open-drain circuit is disconnected, the output end corresponding to the status signal is in a high-impedance state, and a floating signal is output.

[0093] Taking the step-down circuit as an example, Figure 8 A schematic diagram of the structure of another laser projection device provided in another embodiment of the present application is shown in FIG. Figure 8 As shown, the driving unit 31 includes: a seventh switch tube V7, an eighth resistor R8, a second inductor L2, a second capacitor C2 and a third diode VD4.

[0094] One end of the second capacitor C2 is connected to the output end of the power board 10, the positive electrode of the laser 40 and the negative electrode of the third diode VD4, and the other end of the second capacitor C2 is connected to the negative electrode of the laser 40 and one end of the second inductor L2;

[0095] The other end of the second inductor L2 is connected to the anode of the third diode VD4 and one end of the seventh switch tube V7;

[0096] The other end of the seventh switch tube V7 is connected to one end of the eighth resistor R8, and the control end of the seventh switch tube V7 is connected to the second controller 32 to receive the second drive signal; one end of the eighth resistor R8 is connected to the first sampling pin of the second controller 32, and the other end of the eighth resistor R8 is connected to the second sampling pin of the second controller 32 and grounded.

[0097] While you work, continue to refer to Figure 8, the second controller 32 outputs a second drive signal, and the second drive signal is connected to the control end of the seventh switch tube V7 to control the opening and closing of the seventh switch tube V7, wherein the seventh switch tube V7 can be a P-type or N-type MOS tube, or a triode. When the seventh switch tube V7 is turned on, the second capacitor C2 and the second inductor L2 are charged, and when the seventh switch tube V7 is turned off, the second inductor L2 and the second capacitor C2 are discharged, so the output current can be controlled by controlling the turn-on and turn-off time of the seventh switch tube V7, that is, the current is controlled by the duty cycle of the second drive signal. The two ends of the eighth resistor R8 are connected to different pins of the second controller 32, and the eighth resistor R8 can be a sampling resistor. Based on the voltage at the two ends of the sampling resistor, the current flowing through the sampling resistor is obtained. The eighth resistor is connected in series with the laser 40, so based on this, the current flowing through the laser 40 can be sampled.

[0098] The protection module 70 will be exemplarily introduced below.

[0099] Continue as Figure 1-Figure 8 As shown, when the state signal of the protection module 70 is in the first state, the protection module 70 enters the protection mode. In the protection mode, the protection module 70 continuously outputs the protection signal to the power board 10 until the protection mode is exited. Correspondingly, when the state signal of the protection module 70 is in the second state, the protection module 70 enters the normal working mode. In the working mode, the protection module 70 does not output the protection signal. It can be understood that when the protection module 70 receives the first state signal, it enters the protection mode and continuously outputs the protection signal to the power board 10. After the power board 10 receives the protection signal, the power supply path between the power board 10 and the laser driving module 30 is disconnected. Since in the protection mode, the output of the protection signal will not be affected by the state signal, so that the circuit between the power board 10 and the laser 40 is continuously maintained, thereby avoiding repeated overvoltage of the laser 40, thereby protecting the laser 40.

[0100] As for the way in which the protection module 70 exits the protection mode, as an example, the protection module 70 also receives the first power supply input signal VCC1, and the protection module 70 is used to continuously output the protection signal in the protection mode based on the first power supply input signal VCC1, and exit the protection mode when the first power supply input signal VCC1 is disconnected. That is, when the protection module 70 is powered off, the protection module 70 exits the protection mode.

[0101] In some embodiments, Fig. 9 FIG. 1 is a schematic diagram of a structure of a laser projection device provided in another embodiment of the present application. Fig. 9 As shown, the protection module 70 includes: a judgment unit 71 and a signal generation unit 72;

[0102] The judging unit 71 is connected to the laser driving module 30 and the signal generating unit 72, and is used to enter the protection mode when receiving the control signal of the first state, and continuously output the first level to the signal generating unit 72 in the protection mode;

[0103] The signal generating unit 72 is connected to the power board 10 , and is used to output a protection signal to the power board 10 when receiving the first voltage.

[0104] In this embodiment, the protection mode of the protection module 70 is mainly implemented by the judgment unit 71, wherein the judgment unit 71 outputs a first level when receiving a state signal of a first state, and outputs a second level when receiving a state signal of a second state, wherein the first level and the second level are different levels. So that the signal generating unit 72 outputs a protection signal to the power board 10 when receiving the first level.

[0105] As an example, Fig.10 is a schematic diagram of the structure of a protection module in an example. Fig.10 As shown, the judgment unit 71 may include: a first resistor R1, a second resistor R2, a third resistor R3, a first switch tube V1 and a second switch tube V2;

[0106] One end of the first resistor R1 receives the first power supply input signal VCC1, the other end of the first resistor R1 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is connected to one end of the first switch tube V1;

[0107] The other end of the first switch tube V1 is grounded, the control end of the first switch tube V1 is connected to the laser driving module 30, and the first switch tube V1 is turned on when the laser driving module 30 outputs a state signal of the first state;

[0108] One end of the second switch tube V2 is connected to one end of the first resistor R1 and receives the first power supply input signal VCC1. The other end of the second switch tube V2 is connected to one end of the third resistor R3 and is connected to the signal generating unit 72 as an output end. The control end of the second switch tube V2 is connected to the other end of the first resistor R1 and one end of the second resistor R2.

[0109] The other end of the third resistor R3 is connected to the control end of the first switch tube V1.

[0110] In this example, the switch tube can be a triode or a field effect tube. Taking the field effect tube as an example, the control end of the switch tube corresponds to the gate, and one end and the other end correspond to the source or drain. It should also be noted that the first power supply input signal VCC1 can be provided by the power board 10 or can be connected externally. In either case, it is necessary to be able to achieve manual control of connection or non-connection, so as to achieve manual control of the protection module 70 to exit the protection mode.

[0111] The working principle of this example is explained in combination with actual scenarios: Fig.10 , assuming that the state signal of the first state is a high-level signal, and the state signal of the second state is a low-level signal. Take the first switch tube V1 as an NPN-type transistor and the second transistor as a PNP-type transistor as an example. When the control end of the first switch tube V1 receives a low-level signal (the state signal of the second state), the first switch tube V1 is disconnected, and the voltage at point A is the voltage corresponding to the first power supply input signal VCC1, that is, a high-level signal. The second switch tube V2 is turned off, and the voltage at point B is pulled down by the first ground terminal, and a low-level signal is output. Based on the low-level signal, the signal generation unit 72 does not output a protection signal. When the control end of the first switch tube V1 receives a high level signal, the third switch tube V3 is turned on, the voltage at point A between the first resistor R1 and the second resistor R2 becomes low, the second switch tube V2 is turned on, the first power supply input signal VCC1 is connected to the control end of the first switch tube V1, the first switch tube V1 is turned on, and the first switch tube V1 no longer depends on the state signal of the first state provided by the power board 10, and is continuously turned on, that is, enters the protection mode, and the output end B continuously outputs the first level of the high level, so that when the signal generating unit 72 receives the first level, it continuously outputs the protection signal. Until the first power supply input signal VCC1 is disconnected, the protection mode is exited.

[0112] In this example, the control end of the first switch tube V1 is connected to the other end of the second switch tube V2 which serves as the output end, and one end of the first switch tube V1 is connected to the control end of the second switch tube V2, so that the first switch tube V1 triggers the second switch tube V2 to turn on after being turned on, and forms a locked conduction state under the action of the power supply input circuit, so that the first level can be continuously output.

[0113] Based on the above example, Fig.11 is a schematic diagram of the structure of the protection module in another example. Fig.11 As shown, the judgment unit 71 further includes: a fifth resistor R5, a sixth resistor R6, a fourth switch tube V4 and a photoelectric coupler N1.

[0114] One end of the four-switch tube is connected to the secondary output end of the photoelectric coupler N1, the other end of the four-switch tube is grounded, the control end of the four-switch tube is connected to the laser driving module 30, and the fourth switch tube V4 is turned on when receiving the state signal of the first state, and is turned off when receiving the state signal of the second state;

[0115] The secondary input end of the photoelectric coupler N1 is connected to the other end of the sixth resistor R6, the secondary input end of the photoelectric coupler N1 is connected to the other end of the fifth resistor R5, and the secondary output end of the photoelectric coupler N1 is connected to the control end of the first switch tube V1; one end of the fifth resistor R5 receives the third power supply input signal; one end of the sixth resistor R6 receives the first power supply input signal VCC1.

[0116] In this example, the fourth switch tube V4 can be a triode, or a MOS tube. The first power supply input signal VCC1 is the same as the above example, and the third power supply input signal is the power supply signal of the primary side of the photocoupler N1, which can be connected externally or as follows: Figure 6 The exemplary power board 10 outputs a voltage VO2.

[0117] The following is an illustrative description based on specific scenarios: Fig.11 , taking the fourth switch tube V4 as a PNP type transistor, the state signal of the first state is a low level signal, and the state signal of the second state is a high level signal as an example, when the control end of the fourth switch tube V4 receives the high level state signal STA, it is disconnected, the LED lamp on the primary side of the photocoupler N1 does not work, the impedance of the secondary side is large, which is equivalent to a short circuit, the voltage at the control end of the first switch tube V1 receives a floating signal, the first switch tube V1 is disconnected, and the judgment unit 71 does not enter the protection mode; when the control end of the fourth switch tube V4 receives the low level state signal STA, it is turned on, the fourth switch tube V4 is turned on, the LED lamp on the primary side of the photocoupler N1 emits light, the impedance of the secondary side of the photocoupler N1 decreases, the secondary side of the photocoupler N1 is turned on, the voltage at the control end of the first switch tube V1 receives a high level, the first switch tube V1 is turned on, and the judgment unit 71 enters the protection mode and continuously outputs the first level.

[0118] In this example, the fifth resistor R5, the sixth resistor R6, the fourth switch tube V4 and the photocoupler N1 constitute an isolation unit for isolating the primary and secondary winding ends of the transformer. Before isolation, the current flow between the two end circuits shares two grounds and threatens each other. Through physical isolation, the primary and secondary winding ends of the transformer correspond to different ground ends respectively, thereby reducing the safety risks of system operation.

[0119] It should be noted that when the state signal of the first state is a high level or a low level, the state signal of the second state may be a corresponding reverse signal or a floating signal. When it is a floating signal, the fourth switch tube V4 may be mis-turned on based on the unstable floating signal, which will affect the accuracy of the output control signal.

[0120] So in some examples, Fig.12 FIG. 1 is a schematic diagram of the structure of a protection module in another example. Fig.12As shown, the judging unit 71 may further include: a seventh resistor R7,

[0121] One end of the seventh resistor R7 is connected to the primary output end of the photocoupler N1 , and the other end of the seventh resistor R7 is connected to the control end of the fourth switch tube V4 .

[0122] As can be seen from the above example, an open-drain circuit can be provided inside the second controller 32. When the current of the laser 40 is greater than the first threshold, the switch in the open-drain circuit is turned on, the output end corresponding to the state signal is grounded, and a low level is output. When the current of the laser 40 is not greater than the first threshold, the switch in the open-drain circuit is turned off, the output end corresponding to the state signal is in a high-impedance state, and a floating signal is output. In combination with this example, when the second controller 32 outputs a state signal of the first state, wherein the state signal of the first state is a low-level signal, the control end level of the fourth switch tube V4 is pulled low, and when the second controller 32 outputs a floating signal, the seventh resistor R7 raises the control end level of the fourth switch tube V4, so that the fourth switch tube V4 is in a closed state, thereby avoiding mis-conduction.

[0123] The manner in which the power board 10 stops supplying power based on the protection signal will be exemplarily described below in conjunction with the structure of the signal generating unit 72 .

[0124] Combination Figure 5 , Figure 6 As can be seen from the example, the first controller 12 in the power board 10 outputs a voltage to supply power to the laser driving module based on the first driving signal. If the first controller 12 does not receive the first driving signal, it cannot supply power, thereby causing a power supply circuit breaker.

[0125] Based on this, in an example, Fig.13 FIG. 1 is a schematic diagram of the structure of another laser projection device provided in another embodiment of the present application. Fig.13 As shown, the signal generating unit 72 is connected to the enable pin of the first controller 12, and is used to output a protection signal to the enable pin of the first controller 12 when receiving a first level. The protection signal is used to pull down or raise the voltage of the enable pin of the first controller 12 so that the voltage of the enable pin of the first controller 12 is an inactivation voltage.

[0126] In this example, the signal generating unit 72 is connected to the enable pin EN of the first controller 12, and the first controller 12 is used to provide the first drive signal Drv1 / Drv2. Taking the first controller 12 as an MCU as an example, the first controller 12 is provided with an enable pin EN. When the enable pin EN is in an activated state, the first controller 12 works normally and outputs the first drive signal Drv1 / Drv2. When the enable pin EN is in an inactivated state, the first controller 12 does not work, that is, does not output the first drive signal Drv1 / Drv2. The protection signal can be a low-level signal or a high-level signal. The protection signal output by the signal generating unit 72 will pull down or raise the enable pin EN of the MCU, thereby making the enable pin EN inactive. Under normal circumstances, the enable pin EN is usually provided with a power supply signal, so under normal circumstances, the enable pin EN will work normally based on the power supply signal.

[0127] Based on this example, Fig.14 FIG. 1 is a schematic diagram of the structure of a protection module in another example. Fig.14 As shown, the signal generating unit 72 includes: a third switch tube V3, a fourth resistor R4;

[0128] One end of the third switch tube V3 is connected to the enable pin EN of the first controller 12, the other end of the third switch tube V3 is connected to one end of the fourth resistor R4, and the control end of the third switch tube V3 is connected to the output end of the judgment unit 71;

[0129] The other end of the fourth resistor R4 is grounded.

[0130] When working, taking the third switch tube V3 as an NPN-type triode as an example, the first level is a high-level signal. When the control end of the third switch tube V3 receives a high-level signal, the third switch tube V3 is turned on, the output end level of the third switch tube V3 is pulled down, and a low-level signal is output, so that the enable pin EN of the first controller 12 is a low-level signal, and the first controller 12 does not work. When the third switch tube V3 does not receive a high-level signal, the third switch tube V3 is disconnected, the enable pin EN of the first controller 12 continues to receive a high-level signal, the enable pin EN is activated, the first controller 12 outputs the first drive signal Drv1 / Drv2, and the power supply unit 11 outputs the supply voltage normally.

[0131] In this example, the signal generating unit 72 is connected to the enable pin EN of the first controller 12, and the output protection signal deactivates the enable pin EN, so that the first controller 12 does not work, and the power supply unit 11 does not receive the first drive signal Drv1 / Drv2, thereby reducing the output power signal VO1.

[0132] In another example, Fig.15 FIG. 1 is a schematic diagram of the structure of another laser projection device provided in another embodiment of the present application. Fig.15 As shown, in this example, the first driving signal is a PWM signal;

[0133] The signal generating unit 72 is connected to the output end of the first controller 12, and is used to output a protection signal to the output end of the first controller 12 when receiving the first level. The protection signal is used to lower or raise the voltage of the output end of the first controller 12 so that the power supply unit receives a constant level signal.

[0134] In this example, the signal generating unit 72 is connected to the output terminal of the first controller 12, that is, the first controller 12 works normally and outputs the first drive signal Drv1 / Drv2. The protection signal can pull down or raise the voltage of the output terminal of the first controller 12 so that the power supply unit receives a constant level signal. For the first controller 12, continue to refer to Figure 6 When the first driving signal is at a constant level, the fifth switch tube and the sixth switch tube cannot be driven to open and close, so that the power supply unit cannot output the power supply voltage, thereby forming a power supply circuit.

[0135] On this basis, Fig.16 FIG. 1 is a schematic diagram of the structure of a protection module in another example. Fig.16 As shown, the signal generating unit 72 includes: a first diode VD1, a third switch tube V3 and a fourth resistor R4.

[0136] The anode of the first diode VD1 is connected to the output end of the first controller 12, and the cathode of the first diode VD1 is connected to one end of the third switch tube V3;

[0137] The other end of the third switch tube V3 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is grounded.

[0138] In this implementation, similar to the above example, the third switch tube V3 is turned on when receiving the first level, the diode is grounded, and the positive electrode outputs a low-level protection signal. The first diode VD1 is connected to the first drive signal Drv1 / Drv2, which will pull down the voltage at the output end of the first controller 12, so that the voltage at the output end is a low-level protection signal, which is equivalent to the protection signal covering the first drive signal Drv1 / Drv2, thereby making the power supply unit 11 unable to receive the first drive signal Drv1 / Drv2, and thus unable to output the power signal.

[0139] It should be noted that the first diode VD1 is used to prevent external signals from interfering with the first drive signal Drv1 / Drv2, wherein the number of the first diodes VD1 is set according to the form of the power supply board 10. For example, in the above-mentioned LLC circuit 13, the power supply unit 11 includes a fifth switch tube V5 and a sixth switch tube V6, and thus includes two first drive signals Drv1 / Drv2, and correspondingly includes two first diodes VD1.

[0140] The following is an exemplary introduction to this embodiment in combination with actual scenarios: Fig.17 A schematic diagram of the structure of another laser projection device provided in yet another embodiment, Fig.18 is a timing diagram of an input signal of a laser projection device in an example, such as Fig.17 , Fig.18As shown, the state signal of the first state is a low-level signal; the power board 10 includes a first controller 12 and a power supply unit. During the time period 0-t1, the power supply unit receives the first power supply output signal VIN provided by the PFC, and the first controller 12 outputs a first drive signal Drv1 / Drv2 to the power supply unit. The power supply unit supplies power to the laser driving unit 31 based on the first drive signal Drv1 / Drv2. The driving unit 31 of the laser driving module 30 outputs a corresponding power supply voltage based on the second drive signal output by the second controller 32. When the second controller 32 detects that the current of the laser 40 is not greater than the first threshold, it outputs a state signal of the second state to the judgment unit 71. The fourth switch tube V4 in the judgment unit 71 is disconnected, and the secondary output end of the photoelectric coupler N1 outputs a low-level signal. The first switch tube V1, the second switch tube V2, and the first switch tube V3 are disconnected. The three switch tubes V3 are disconnected, the judgment unit 71 does not enter the protection mode, the signal generation unit 72 outputs the second level signal, and the first controller 12 continues to work; within the time period t1-t2, the laser driving module 30 is short-circuited, and when the current of the laser 40 is greater than the first threshold, the laser driving module 30 outputs the state signal of the first state, the fourth switch tube V4 is turned on, the secondary output end of the photoelectric coupler N1 outputs a high level signal, the first switch tube V1 is turned on, the control end of the second switch tube V2 is low level, the second switch tube V2 is turned on, the voltage at the output end B becomes high, and the first level is output, the third switch tube V3 in the signal generation unit 72 is turned on, the enable pin EN of the first controller 12 is pulled low, the first controller 12 stops working, does not output the first drive signal Drv1 / Drv2, and the output voltage of the power supply unit gradually decreases until it is zero. And after the moment t2, the current flowing through the laser 40 is 0, which is less than the predetermined first threshold, and the first controller 12 outputs the state signal of the second state. However, at this time, under the action of the first power supply input signal VCC1, the judgment unit 71 makes the control terminal voltage of the first switch tube V1 always at a high level, thereby making the first switch tube V1 and the second switch tube V2 always in the on state, and the judgment unit 71 enters the protection mode, and continuously outputs the first high level until time t3, when the first power supply input signal VCC1 is stopped, and the laser projection equipment can be repaired at this time; at time t4, the first power supply input signal VCC1 is reconnected, and the power signal gradually increases until t5 reaches the normal working power supply voltage, thereby protecting the laser 40.

[0141] In the laser projection device provided in this embodiment, the power board provides voltage to the laser driving module to form a power supply path. The laser driving module drives the laser to emit light or extinguish based on the laser driving signal output by the received display control module. When the current flowing through the laser is detected to be greater than the first threshold, the state signal of the first state is output. When the current flowing through the laser is detected to be not greater than the first threshold, the state signal of the second state is output; the protection module is connected to the laser driving module and the power board, and enters the protection mode when receiving the state signal of the first state. In the protection mode, the protection circuit continuously outputs the protection signal to the power board until the protection mode is exited. The protection signal causes the power board to stop outputting voltage to the laser driving module, forming a power supply circuit. In this scheme, when the state signal of the protection module is in the first state, the protection module enters the protection mode and continuously outputs the protection signal to the signal generating unit. Since the output of the protection signal is not affected by the change of the state signal in the protection mode, the circuit between the power board and the laser is continuously maintained, thereby avoiding repeated overvoltage of the laser, thereby protecting the laser.

[0142] It should be noted that the above embodiment only illustrates a scenario in which the laser projection device includes one laser. In some laser projection devices such as laser TVs, lasers of three colors are included, so there can be multiple lasers. In this scenario, the laser projection device includes multiple laser drive modules, multiple lasers, and multiple protection modules. These circuits correspond one to one, and multiple protection modules correspond to one power board, that is, each protection module is used to output a protection signal when the corresponding laser drive module outputs a state signal of the first state. It can be understood that as long as one protection module outputs a protection signal, the power board stops supplying power. Thereby, protection of multiple lasers is achieved. The working principle of each laser drive module, laser, and protection module is the same as the principle of the laser drive module, laser, and protection module in any of the above embodiments. For details, please refer to the above embodiments, which will not be repeated here.

[0143] In some other embodiments, a control method of a laser projection device is also provided, wherein the laser projection device comprises: a display control module, a power board, a laser driving module and a protection module, and the method comprises:

[0144] The laser driving module receives the laser driving signal output by the display control module to drive the laser to emit light or extinguish; and outputs a state signal of a first state when detecting that the current flowing through the laser is greater than a first threshold value, and outputs a state signal of a second state when detecting that the current flowing through the laser is not greater than the first threshold value; the laser driving module is connected to the power supply board, and forms a power supply path with the power supply based on the voltage provided by the power supply board;

[0145] The protection module enters a protection mode when receiving a control signal of a first state, and in the protection mode, continuously outputs a protection signal to the power board until exiting the protection mode; the protection signal is used to cause the power board to stop outputting voltage to the laser driving module, thereby forming a power supply circuit.

[0146] The specific structure of the laser projection device in this embodiment can refer to any of the above embodiments and will not be described in detail here.

[0147] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the claims.

[0148] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A laser projection device, characterized in that: Including: laser light source, light modulation device, projection lens, display control module, power board, laser drive module and protection module, The power board provides voltage to the laser driving module to form a power supply path; The laser light source comprises a laser, which is used to emit a laser beam to provide an illumination beam for the device; The display control module is used to output a laser driving signal and an image display driving signal for driving the light modulation device; The light modulation device modulates the laser beam under the drive of the image display driving signal; The projection lens is used to receive the modulated laser beam and project an image; The laser driving module is arranged between the display control module and the laser, and is used to receive the laser driving signal to drive the laser to emit light or extinguish; and when it is detected that the current flowing through the laser is greater than a first threshold, output a state signal of a first state, and when it is detected that the current flowing through the laser is not greater than the first threshold, output a state signal of a second state; The protection module is connected to the laser driving module and the power board, and is used to enter a protection mode when receiving a control signal of a first state, and in the protection mode, continuously output a protection signal to the power board until exiting the protection mode; the protection signal is used to make the power board stop outputting voltage to the laser driving module, forming a power supply circuit.

2. The laser projection device according to claim 1, characterized in that: The protection module also receives a first power supply input signal. The protection module is configured to continuously output the protection signal in a protection mode based on the first power supply input signal, and exit the protection mode when the first power supply input signal is disconnected.

3. The laser projection device according to claim 1, characterized in that: The protection module includes: a judgment unit and a signal generation unit; The judgment unit is connected to the laser driving module and the signal generating unit, and is used to enter a protection mode when receiving a control signal of a first state, and continuously output a first level to the signal generating unit in the protection mode; The signal generating unit is connected to the power board, and is used to output the protection signal to the power board when receiving the first voltage.

4. The laser projection device according to claim 3, characterized in that: The power board includes: a first controller and a power supply unit, The first controller is connected to the power supply unit and is used to output a first driving signal to the power supply unit; The power supply unit is connected to the laser driving module and receives a second power supply input signal. The power supply unit is used to supply power to the laser driving module based on the second power supply input signal and under the control of the first driving signal.

5. The laser projection device according to claim 4, characterized in that: The signal generating unit is connected to the enable pin of the first controller, and is used to output the protection signal to the enable pin of the first controller when receiving the first level. The protection signal is used to pull down or raise the voltage of the enable pin of the first controller so that the voltage of the enable pin of the first controller is an inactivation voltage.

6. The laser projection device according to claim 4, characterized in that: The first driving signal is a PWM signal; The signal generating unit is connected to the output end of the first controller, and is used to output the protection signal to the output end of the first controller when receiving the first level. The protection signal is used to lower or raise the voltage of the output end of the first controller so that the power supply unit receives a constant level signal.

7. The laser projection device according to claim 3, characterized in that: The judging unit comprises: a first resistor, a second resistor, a third resistor, a first switch tube and a second switch tube; One end of the first resistor receives a first power supply input signal, the other end of the first resistor is connected to one end of the second resistor, and the other end of the second resistor is connected to one end of the first switch tube; The other end of the first switch tube is grounded, the control end of the first switch tube is connected to the laser driving module, and the first switch tube is turned on when the laser driving module outputs a state signal of a first state; One end of the second switch tube is connected to one end of the first resistor and receives the first power supply input signal, the other end of the second switch tube is connected to one end of the third resistor and is connected to the signal generating unit as an output end, and the control end of the second switch tube is connected to the other end of the first resistor and one end of the second resistor; The other end of the third resistor is connected to the control end of the first switch tube.

8. The laser projection device according to claim 7, characterized in that: The judgment unit further includes: a fifth resistor, a sixth resistor, a fourth switch tube and a photoelectric coupler. One end of the four-switch tube is connected to the secondary output end of the photoelectric coupler, the other end of the four-switch tube is grounded, the control end of the four-switch tube is connected to the laser driving module, and the fourth switch tube is turned on when receiving the state signal of the first state, and is turned off when receiving the state signal of the second state; The secondary input end of the photoelectric coupler is connected to the other end of the sixth resistor, the secondary input end of the photoelectric coupler is connected to the other end of the fifth resistor, and the secondary output end of the photoelectric coupler is connected to the control end of the first switch tube; one end of the fifth resistor receives a third power supply input signal; one end of the sixth resistor receives the third power supply input signal.

9. The laser projection device according to claim 5, characterized in that: The signal generating unit comprises: a third switch tube and a fourth resistor; One end of the third switch tube is connected to the enable pin of the first controller, the other end of the third switch tube is connected to one end of the fourth resistor, the control end of the third switch tube is connected to the output end of the judgment unit, and the third switch tube is turned on when receiving the first level, and is turned off when not receiving the first level; The other end of the fourth resistor is grounded.

10. The laser projection device according to claim 6, characterized in that: The signal generating unit includes: a first diode, a third switch tube and a fourth resistor. The anode of the first diode is connected to the output end of the first controller, and the cathode of the first diode is connected to one end of the third switch tube; The other end of the third switch tube is connected to one end of the fourth resistor, the control end of the third switch tube is connected to the output end of the judgment unit, and the third switch tube is turned on when receiving the first level, and is turned off when not receiving the first level; The other end of the fourth resistor is grounded.

11. A control method for a laser projection device, characterized in that: The laser projection device comprises: a display control module, a power board, a laser driving module and a protection module, and the method comprises: The laser driving module receives the laser driving signal output by the display control module to drive the laser to emit light or extinguish; and outputs a state signal of a first state when detecting that the current flowing through the laser is greater than a first threshold value, and outputs a state signal of a second state when detecting that the current flowing through the laser is not greater than the first threshold value; the laser driving module is connected to the power supply board, and forms a power supply path with the power supply based on the voltage provided by the power supply board; The protection module enters a protection mode when receiving a control signal of a first state, and in the protection mode, continuously outputs a protection signal to the power board until exiting the protection mode; the protection signal is used to cause the power board to stop outputting voltage to the laser driving module, thereby forming a power supply circuit.

Images