CN214311266U

CN214311266U - Laser projection device

Info

Publication number: CN214311266U
Application number: CN202120432658.5U
Authority: CN
Inventors: 李有贵; 刘广学
Original assignee: Qingdao Hisense Laser Display Co Ltd
Current assignee: Qingdao Hisense Laser Display Co Ltd
Priority date: 2021-02-26
Filing date: 2021-02-26
Publication date: 2021-09-28
Anticipated expiration: 2031-02-26

Abstract

The application provides a laser projection device, this laser projection device includes: the laser driving circuit comprises a main control circuit, a laser and a laser driving circuit; the laser driving circuit comprises a driving signal generating circuit, a high-frequency driving circuit and a switch; the main control circuit is used for outputting an initial enable signal and an initial current control signal according to a display image and transmitting the signals to the driving signal generating circuit; the driving signal generating circuit responds to the initial enabling signal and the initial current control signal and outputs a driving signal to the laser; the negative electrode of the laser is connected with one end of the switch, and the other end of the switch is grounded; the high-frequency driving circuit is connected with the control end of the switch; when the switch is switched on, the driving signal drives the laser to emit light; the high-frequency driving circuit is used for generating a high-frequency signal for controlling the switch to be switched on or switched off so as to drive the laser at a high frequency based on the high-frequency signal. Through the laser projection equipment, the occurrence of interference phenomenon of laser in the transmission process is avoided, and the problem of speckles during equipment imaging is solved.

Description

Laser projection device

Technical Field

The application relates to the technical field of electronics, especially, relate to a laser projection equipment.

Background

At present, laser light is often applied to display fields, for example, laser projection apparatuses such as laser televisions and laser projectors, due to its high brightness characteristic and monochromaticity.

Generally, when a laser module in a laser projection device is driven to emit light, due to the narrow line width of the laser emitted by the laser module, if the laser is directly projected onto a screen of the laser projection device, an image displayed on the screen may have obvious speckles, which affects the image quality.

Therefore, how to avoid the interference phenomenon in the laser projection device is an urgent problem to be solved.

SUMMERY OF THE UTILITY MODEL

The application provides a laser projection equipment for solve current laser projection equipment, appear the problem of interference fringe easily when carrying out image display.

The application provides a laser projection device, which comprises a main control circuit, a laser and a laser driving circuit; the laser driving circuit comprises a driving signal generating circuit, a high-frequency driving circuit and a switch; wherein,

the main control circuit is connected with the driving signal generating circuit, is used for outputting an initial enabling signal and an initial current control signal according to a display image, and transmits the initial enabling signal and the initial current control signal to the driving signal generating circuit; the output end of the driving signal generating circuit is connected with the anode of the laser and used for responding to the initial enabling signal and the initial current control signal and outputting a driving signal to the laser;

the negative electrode of the laser is connected with one end of the switch, and the other end of the switch is grounded; the high-frequency driving circuit is connected with the control end of the switch; when the switch is switched on, the driving signal flows through the laser to drive the laser to emit light; the high-frequency driving circuit is used for generating a high-frequency signal; the switch is used for switching on or off under the control of the high-frequency signal so as to drive the laser at high frequency based on the high-frequency signal.

In some embodiments of the present application, the main control circuit is connected to the laser and the high frequency driving circuit, and further configured to generate a first control signal and/or a second control signal according to a voltage signal and a current signal of the laser; the first control signal is used for adjusting the driving signal generated by the driving signal generating circuit, and the second control signal is used for adjusting the high-frequency signal generated by the high-frequency driving circuit.

In some embodiments of the present application, the laser projection device further comprises a first sampling circuit;

the first sampling circuit is used for collecting a voltage signal and a current signal of the laser; the main control circuit is respectively connected with the first sampling circuit, the driving signal generating circuit and the high-frequency driving circuit and is used for generating a third control signal and/or a fourth control signal according to a voltage signal and a current signal of the laser; the third control signal is used for adjusting the driving signal generated by the driving signal generating circuit, and the fourth control signal is used for adjusting the high-frequency signal generated by the high-frequency driving circuit.

In some embodiments of the present application, the laser projection device further comprises a second sampling circuit;

the second sampling circuit is connected with the output end of the driving signal generating circuit and the output end of the high-frequency driving circuit and is used for collecting the driving signal output by the driving signal generating circuit and the high-frequency signal output by the high-frequency driving circuit; the input end of the driving signal generating circuit is connected with the second sampling circuit and used for adjusting the driving signal currently output by the driving signal generating circuit according to the driving signal collected by the sampling circuit; and the input end of the high-frequency driving circuit is connected with the second sampling circuit and is used for adjusting the high-frequency signal currently output by the high-frequency driving circuit according to the high-frequency signal acquired by the sampling circuit.

In some embodiments of the present application, the lasers include a red laser, a green laser, and a blue laser; the lasers with different colors correspond to the driving signal generating circuits one by one.

In some embodiments of the present application, the master control circuit comprises: an algorithm processor and a control processor; wherein,

the algorithm processor is used for generating initial enabling signals and initial current control signals corresponding to the lasers with different colors according to the received image signals; and the control processor is connected with the algorithm processor and the driving signal generating circuits corresponding to the lasers with different colors respectively, and is used for sending the initial enabling signal and the initial current control signal corresponding to the laser with each color to the driving signal generating circuit corresponding to the laser with the color.

In some embodiments of the present application, the laser projection device further comprises; a light modulation device; the optical modulation device is connected with the control processor and the laser;

the algorithm processor sends image display data to the light modulation device through the control processor; the light modulation device is used for modulating the light of the laser emitted by the laser according to the image display data so as to reflect, project and display the laser emitted by the laser.

In some embodiments of the present application, the high frequency driving circuit includes: a high-frequency driving chip;

the input end of the high-frequency driving chip is connected to the main control circuit, and the output end of the high-frequency driving chip is connected with the control end of the switch; the main control circuit is also used for generating an initial high-frequency signal; the high-frequency driving chip is used for responding to the initial high-frequency signal generated by the main control circuit and outputting a high-frequency signal for driving the switch to the control end of the switch.

In some embodiments of the present application, the high frequency driving circuit includes: the high-frequency signal generator and the high-frequency driving chip;

the input end of the high-frequency driving chip is connected with the high-frequency signal generator, and the output end of the high-frequency driving chip is connected with the control end of the switch; the high-frequency signal generator is used for generating an initial high-frequency signal; the high-frequency driving chip is used for responding to the initial high-frequency signal generated by the high-frequency signal generator and outputting a high-frequency signal for driving the switch to the control end of the switch.

In some embodiments of the present application, the laser driving circuit further includes: an energy transfer member;

one end of the energy transfer component is connected with the negative electrode of the laser, when the switch is switched on, the driving signal flows through the laser to drive the laser to emit light, and energy is stored in a parasitic energy storage element formed between the laser and the switch; when the switch is turned off, the energy stored on the parasitic energy storage element is transferred through the energy transfer component.

In some embodiments of the present application, the energy transfer member comprises: a resistor and a capacitor;

one end of the capacitor is connected with the negative electrode of the laser, the other end of the capacitor is connected with one end of the resistor, and the other end of the resistor is grounded; when the switch is turned off, the energy stored in the parasitic energy storage element is transferred through the resistor and the capacitor in sequence.

In some embodiments of the present application, the energy transfer member comprises: a diode;

the anode of the diode is connected with the cathode of the laser; the cathode of the diode is connected with the anode of the laser; when the switch is turned off, the energy stored in the parasitic energy storage element is transferred to the laser through the diode to be consumed.

The application provides a laser projection device, this laser projection device includes: the laser driving circuit comprises a main control circuit, a laser and a laser driving circuit; the laser driving circuit comprises a driving signal generating circuit, a high-frequency driving circuit and a switch; the main control circuit is connected with the driving signal generating circuit, is used for outputting an initial enabling signal and an initial current control signal according to a display image, and transmits the initial enabling signal and the initial current control signal to the driving signal generating circuit; the output end of the driving signal generating circuit is connected with the anode of the laser and used for responding to the initial enabling signal and the initial current control signal and outputting a driving signal to the laser; the negative electrode of the laser is connected with one end of the switch, and the other end of the switch is grounded; the high-frequency driving circuit is connected with the control end of the switch; when the switch is switched on, a driving signal flows through the laser to drive the laser to emit light; the high-frequency driving circuit is used for generating a high-frequency signal; and the switch is used for switching on or off under the control of a high-frequency signal to drive the laser at a high frequency based on the high-frequency signal. By the high-frequency driving mode, interference of laser in the transmission process is avoided, and the problem of interference fringes of laser projection equipment during imaging is solved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application.

Fig. 1 is a schematic structural diagram of a first laser projection apparatus provided in an embodiment of the present application;

fig. 2 is a schematic structural diagram of a second laser projection apparatus provided in an embodiment of the present application;

fig. 3 is a schematic circuit structure diagram of a driving signal generating circuit according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a third laser projection apparatus provided in the embodiment of the present application;

fig. 5 is a schematic structural diagram of a fourth laser projection apparatus provided in this embodiment of the present application

Fig. 6 is a schematic structural diagram of a fifth laser projection apparatus provided in the embodiment of the present application;

fig. 7 is a schematic structural diagram of a high frequency driving circuit according to an embodiment of the present disclosure;

fig. 8 is a schematic circuit structure diagram of a first laser driving circuit according to an embodiment of the present disclosure;

fig. 9 is a schematic structural diagram of a sixth laser projection apparatus according to an embodiment of the present disclosure;

FIG. 10 is a schematic current flow diagram of a laser projection apparatus provided herein;

FIG. 11 is a schematic current flow diagram of another laser projection apparatus provided herein;

fig. 12 is a schematic circuit structure diagram of a second laser driving circuit according to an embodiment of the present disclosure;

fig. 13 is a schematic diagram illustrating a current variation of a laser according to an embodiment of the present disclosure;

fig. 14 is a schematic circuit structure diagram of a third laser driving circuit according to an embodiment of the present disclosure;

fig. 15 is a schematic circuit structure diagram of a fourth laser driving circuit according to an embodiment of the present disclosure.

With the above figures, there are shown specific embodiments of the present application, which will be described in more detail below. These drawings and written description are not intended to limit the scope of the inventive concepts in any manner, but rather to illustrate the inventive concepts to those skilled in the art by reference to specific embodiments.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

Currently, laser light is gradually applied to the display field by virtue of its excellent brightness characteristics, color development characteristics, and low power consumption. Taking a laser television as an example, the laser television is generally provided with a laser component for emitting laser to a projection screen of the laser television and finally displaying an image on the projection screen. However, since the laser itself has a narrow spectral line width, the laser is prone to generate interference phenomenon and form speckles if it encounters a rough surface (e.g., a projection screen or a display screen) during transmission, and if it is not adjusted, obvious interference fringes or speckles appear on the display screen, which seriously affects the final imaging quality.

Although some methods for eliminating laser speckle exist at present, most methods are improved on the transmission path of laser light. For example, a diffuser is added to the transmission path of the laser beam to homogenize the speckle, or a polarizer is added to the transmission path of the laser beam to change the polarity of the laser beam having linearly polarized light characteristics. However, the above methods have certain limitations in the implementation process. For example, in the transmission process of lasers with different primary colors, different speckle conditions can be generated due to different optical characteristics, and the speckle eliminating devices with the same specification are additionally arranged in the transmission path to achieve the targeted speckle eliminating effect, for example, when the same speckle eliminating devices are arranged in the same optical path, the improvement effect on the blue speckle is better than that of the red speckle. This has led to the hindrance of the application of two-color or three-color laser television sets.

The application provides a laser projection equipment, aims at solving prior art technical problem as above.

The following describes the technical solutions of the present application and how to solve the above technical problems with specific embodiments. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a first laser projection apparatus provided in an embodiment of the present application. As shown in fig. 1, the laser projection apparatus includes: the laser driving circuit comprises a main control circuit, a laser and a laser driving circuit; the laser driving circuit includes a driving signal generating circuit, a high frequency driving circuit, and a switch.

The main control circuit is connected with the driving signal generating circuit and used for outputting an initial enable signal (EN) and an initial current control signal (PWM) according to the received display image signal and transmitting the signals to the driving signal generating circuit. In particular, the initial enable signal may be used to indicate that a certain color of the lasers is emitting light. The initial current control signal is used for indicating the light-emitting duration and the light-emitting brightness of the laser. For example, after receiving an externally input image signal, the main control circuit analyzes the image signal (e.g., analyzes color distribution information and brightness information in the image signal), and outputs an initial enable signal and an initial current control signal to the laser driving circuit to indicate the voltage and current of the driving signal output by the laser driving circuit.

The output end of the driving signal generating circuit is connected with the anode of the laser, and the driving signal generating circuit is used for responding to the initial enabling signal and the initial current control signal and outputting a driving signal to the laser, wherein the driving signal can be used for driving the laser to emit light; the negative pole of the laser is connected with one end of the switch, and the other end of the switch is grounded. The high-frequency driving circuit is connected with the control end of the switch, and when the switch is conducted, the driving signal generated by the driving signal generating circuit flows through the laser to drive the laser to emit light. In addition, the high-frequency driving circuit is used for generating a high-frequency signal for controlling the switch to be switched on or switched off; the switch is turned on or off under the control of the high-frequency signal, and high-frequency driving is performed on the laser based on the received high-frequency signal. Specifically, the laser driving circuit and the main control circuit in the present application may be separately disposed on different circuit boards (for example, the laser driving circuit may be disposed on a power board in the laser projection apparatus, and the control circuit may be disposed on a display board in the laser projection apparatus), or may be integrated on the same circuit board.

The laser projection equipment that this application embodiment provided, through add high frequency drive circuit, switch, drive signal generation circuit in the laser drive circuit in laser projection equipment and change the drive mode of laser instrument work for the spectrum broadening of the laser that the laser instrument launched under laser drive circuit's drive, and then on the basis that does not change the laser transmission route, reduce the emergence that laser interfered the phenomenon in the transmission course, and then speckle appears in avoiding final display image, improve display image quality.

Fig. 2 is a schematic structural diagram of a second laser projection device according to an embodiment of the present disclosure, and based on the laser projection device shown in fig. 1, in the laser projection device shown in fig. 2, a main control circuit is further connected to the laser and the high-frequency driving circuit, respectively. The main control circuit is used for generating a first control signal and/or a second control signal according to the acquired voltage signal and current signal of the laser; the first control signal is used for adjusting the driving signal generated by the driving signal generating circuit, and the second control signal is used for adjusting the high-frequency signal generated by the high-frequency driving circuit.

Specifically, in order to determine whether the voltage signal and the current signal passing through the laser at the current time are in accordance with the signal parameters analyzed by the main control circuit according to the image information, the main control circuit collects the voltage signal and the current signal in the laser in real time and compares the voltage signal and the current signal with the signal parameters analyzed by the main control circuit, so as to further determine whether to continue to adjust.

If the voltage and the current passing through the laser do not meet the signal parameters determined by the main control circuit, the main control circuit further generates a first control signal and/or a second control signal according to the difference value between the voltage and the current passing through the laser and the parameters determined by the main control circuit. The first control signal is control information sent to the laser driving circuit, and is used to indicate a parameter of the driving signal output by the laser driving circuit, for example, the parameter of the driving signal may include a current value of the driving signal. The second control signal is control information sent to the high-frequency driving circuit and is used for indicating parameters of the high-frequency signal output by the high-frequency driving circuit, for example, the parameters of the high-frequency signal may include the amplitude, the frequency, the duty ratio and the like of the current. Thus, the drive signal generation circuit outputs the adjusted drive signal to the laser, and the high-frequency drive circuit outputs the adjusted high-frequency signal to the switch.

In this application, master control circuit among the laser projection equipment can be used for gathering the voltage electric current isoparametric of laser instrument department to according to the parameter information that the collection obtained, further generate first control signal and/or second control signal, thereby make drive signal generating circuit and high frequency drive circuit can adjust the output of self according to the control signal that receives separately, and then guarantee the accuracy to laser instrument light emission control.

Fig. 3 is a schematic circuit structure diagram of a driving signal generating circuit according to an embodiment of the present disclosure. As shown in fig. 3, the driving signal generating circuit includes a voltage-reducing dc-to-dc controller 31. The controller 31 mainly functions to generate a drive signal for driving the laser.

The signal output from the status pin of the controller 31 may represent fault information of the controller 31, for example, when the controller 31 is operating normally, a low signal may be input; if the controller 31 fails, a high signal may be output. The rt pin of the controller 31 may be used to control the frequency of the output driving signal, and specifically, the frequency of the output driving signal may be adjusted by adjusting a resistor connected to the rt pin.

The adim pins and the pwm pins of the controller 31 may be connected to the main control circuit, and are configured to receive an initial enable signal and an initial current control signal sent by the main control circuit. For example, the initial current control signal may be a pulse modulation signal, which may be transmitted to the controller 31 through the pwm pin, wherein the pulse modulation signal may be used to adjust the on-off duration of the current of the output driving signal and the brightness information of the laser. In addition, the signal received by the controller 31 may further include a voltage control signal for analog dimming, which may be transmitted to the controller 31 through an adim pin, and is mainly used to adjust the voltage value output by the driving signal.

The drv pin of the controller 31 is further connected with a control switch 32, the controller 31 can output a driving signal when the control switch 32 is turned on, and when the control switch 32 is turned on, at the isen pin of the controller 31, the controller 31 can also sample the output driving signal by using a resistor and a capacitor connected with the pin, and feed back the sampled driving signal parameter to the controller 31 through the isen pin, so that the controller 31 adjusts the on and off of the control switch 32 according to the signal input by the main control circuit and the sampled parameter fed back. For example, when the controller 31 determines that the current parameter value of the output driving signal is large, the control switch 32 may be closed to stop outputting the driving signal to the laser.

In the driving signal generating circuit provided by this embodiment, the driving signal generating circuit itself can collect parameters of the output driving signal, and feed back the collected parameters to the controller itself, so that the controller further adjusts the output driving signal according to the collected parameters, thereby ensuring the accuracy of the laser emitted by the laser, and further ensuring the generated image quality.

Fig. 4 is a schematic structural diagram of a third laser projection apparatus provided in an embodiment of the present application. On the basis of the structure of the laser projection apparatus shown in fig. 1, the laser projection apparatus of this embodiment further includes: a first sampling circuit.

Specifically, after the main control circuit controls the driving signal generation circuit and the high-frequency driving circuit to work, the first sampling circuit can acquire voltage signals and current signal changes (for example, changes of amplitude, duty ratio and the like of current and voltage of the laser) of the laser in real time and feed the acquired signal change information back to the main control circuit, so that the main control circuit judges whether the driving signal generation circuit and/or the high-frequency driving circuit need to be adjusted.

In this embodiment, a first sampling circuit is additionally disposed in the laser projection device, and the first sampling circuit can realize real-time monitoring of laser signal transformation, so that the main control circuit adjusts current and voltage signals passing through the laser through controlling the driving signal generating circuit and the high-frequency driving circuit, and further realizes adjustment of the working state of the laser (for example, the light emitting brightness of the laser, the light emitting duration of the laser, and the like).

Fig. 5 is a schematic structural diagram of a fourth laser projection apparatus provided in the embodiment of the present application. On the basis of the structure of the laser projection device shown in fig. 1, a second sampling circuit is further included in the laser projection device.

And the output end of the second sampling circuit and the output end of the driving signal generating circuit are used for acquiring the driving signal output by the driving signal generating circuit. The input end of the driving signal generating circuit is connected with the second sampling circuit and used for adjusting the driving signal currently output by the driving signal generating circuit according to the driving signal collected by the sampling circuit;

the second sampling circuit is also connected with the output end of the high-frequency driving circuit and is used for collecting the high-frequency signal output by the high-frequency driving circuit. The input end of the high-frequency driving circuit is connected with the second sampling circuit and used for adjusting the high-frequency signal output currently according to the high-frequency signal collected by the sampling circuit.

Specifically, when the second sampling circuit is arranged, the driving signal generating circuit may include the second sampling circuit, and the high-frequency driving circuit may also include the second sampling circuit, in the example, the laser driving circuit and the high-frequency driving circuit are both provided with control chips, and these control chips each include respective feedback input pins, the sampling circuits may respectively collect respective output signals, and then feed back to the control chips themselves, and the control chips themselves adjust the output signals. For example, in the laser driving circuit shown in fig. 3, when the controller determines that the current value of the output driving signal is larger, the control switch connected to the controller may be turned off to stop outputting the driving signal to the laser, so as to adjust the output driving signal.

Or the second sampling circuit may be provided independently of the drive signal generating circuit and the high-frequency drive circuit.

In this application embodiment, the second sampling circuit can also be used to gather the signal of high frequency drive circuit and drive signal generation circuit output respectively to signal feedback to self that will gather, then self adjusts the circuit according to the signal of feeding back again, so that the signal of output satisfies the signal parameter of master control circuit transmission, and then ensures the luminous accuracy of laser.

Fig. 6 is a schematic structural diagram of a fifth laser projection apparatus according to an embodiment of the present application. In some embodiments, as shown in fig. 6, the lasers include a red laser, a green laser, and a blue laser, wherein the lasers of different colors are connected with different driving signal generating circuits, that is, each laser corresponds to a respective driving signal generating circuit, and each laser receives a driving signal transmitted by its corresponding driving signal generating circuit. And the high-frequency driving circuit in the laser projection equipment is used for generating a high-frequency signal (D) to control the on-off of the switch corresponding to the laser.

In addition, the main control circuit comprises an algorithm processor and a control processor; the algorithm processor is used for generating an initial enable signal (EN) and an initial current control signal (PWM) according to a received image signal, and the initial enable signals corresponding to the lasers with different colors are different from the initial current control signal, wherein the initial enable signal and the initial current control signal corresponding to the red laser are respectively represented by R _ EN and R _ PWM; an initial enabling signal and an initial current control signal corresponding to the green laser are respectively represented by G _ EN and G _ PWM; the initial enable signal and the initial current control signal for the blue laser are denoted by B _ EN and B _ PWM, respectively.

And the control processor is connected with the algorithm processor and is used for sending the initial enable signal and the initial current control signal to the corresponding driving signal generating circuit. For example, the controller processor may send an enable signal corresponding to the red laser and the initial current control signal to the driving signal generation circuit corresponding thereto, so that the driving signal generation circuit may drive the red laser to operate based on the driving signal output by the driving signal generation circuit.

On the basis of the structure, the laser projection equipment also comprises an optical modulation device. And the optical modulation device is connected with the control processor and the laser and is used for carrying out optical modulation on the laser emitted by the laser according to image display data (namely, image signals received by the algorithm processor) so as to enable the laser emitted by the laser to reflect, project and display.

For example, the light modulation may be a Digital Micromirror Device (DMD) for changing the angle information of thousands of tiny mirrors on the surface of the DMD according to the image display data, for example, the mirrors perform positive angle or negative angle flipping according to the image display data, so as to reflect the laser light emitted by the laser to the projection lens, and project the light beam onto the projection screen through the projection lens.

In some examples, the high frequency drive circuit includes: and the input end of the high-frequency driving chip is connected to the main control circuit, and the output end of the high-frequency driving chip is connected with the control end of the switch. The main control circuit is used for generating an initial high-frequency signal and sending the initial high-frequency signal to a high-frequency driving chip connected with the main control circuit. The high-frequency driving chip can respond to an initial high-frequency signal generated by the main control circuit and process the initial high-frequency signal into a high-frequency signal with driving capability, wherein the high-frequency signal is input through a control end of the switch, and the high-frequency signal can be used for driving the switch to be switched on or switched off.

Fig. 7 is a schematic structural diagram of a high-frequency driving circuit according to an embodiment of the present disclosure. As shown IN fig. 7, the high frequency driving chip 22 is included, and after receiving the high frequency signal (Driver signal) transmitted by the input terminals (IN1 terminal, IN2 terminal), the high frequency driving chip 22 processes the high frequency signal to improve the driving capability of the high frequency signal, wherein the driving capability may be a parameter such as signal power. After the high-frequency driving chip 22 processes the high-frequency signal (Driver signal), the on/off of the switch 12 is controlled by the processed high-frequency signal, so as to realize the high-frequency driving of the laser 11. The switch 12 may be a SiC or GaN switch with high on/off speed, high frequency, and high temperature resistance. When the driving signal generating circuit shown in fig. 3 is used in combination with the high-frequency driving circuit shown in fig. 7, the output terminals (VOUT +, VOUT-) in fig. 3 may be connected to VBUS and ground in fig. 7, respectively, and the driving signal may be input to the circuit shown in fig. 7 by using the circuit shown in fig. 3. In addition, in fig. 7, the high frequency signal (Driver signal) can be directly generated by the main control circuit.

In some examples, the high frequency drive circuit includes: the high-frequency drive circuit includes: a high-frequency signal generator 21 and a high-frequency driving chip 22.

The input end of the high-frequency driving chip is connected with the high-frequency signal generator, and the output end of the high-frequency driving chip is connected with the control end of the switch; the high-frequency signal generator is used for generating an initial high-frequency signal; the high-frequency driving chip is used for responding to the initial high-frequency signal generated by the high-frequency signal generator and outputting a high-frequency signal for driving the switch to the control end of the switch. Specifically, in the actual circuit, the high-frequency signal generator may be disposed in the structure of the circuit board where the main control circuit is located, or may be disposed in the structure of the circuit board where the high-frequency driving circuit is located.

Fig. 8 is a schematic circuit structure diagram of a first laser driving circuit according to an embodiment of the present disclosure. As shown in fig. 8, fig. 8 includes a high-frequency signal generator 21, a high-frequency driving chip 22, a switch 12, and an equivalent parasitic inductance formed between the laser 11 and the switch. The power supply input terminal (VCC terminal) of the high-frequency signal generator 21 is configured to receive an external power supply signal (VDD terminal), so that the high-frequency signal generator 21 operates, and the external power supply signal may be filtered by the filter capacitor and then supplies power to the high-frequency signal generator 21.

The signal output terminals (OUTN terminal, OUTP terminal) of the high-frequency signal generator 21 are connected to the signal input terminals (IN1 terminal, IN2 terminal) of the high-frequency driving chip 22, for transmitting the initial high-frequency signal generated by the high-frequency signal generator 21 to the high-frequency driving chip 22.

The power supply input terminal (VCC terminal) of the high frequency driving chip 22 is configured to receive an external power supply signal (VDD terminal), so that the high frequency driving chip 22 operates, the external power supply signal may be filtered by a filter capacitor and then supplied to the high frequency driving chip, and the high frequency driving chip 22 is configured to convert the received initial high frequency signal into a high frequency signal with driving capability, so as to enable the high frequency signal to control the on/off of the switch 12.

The positive terminal of the laser 11 is connected to an external power supply terminal (VBUS terminal) for receiving an external driving signal. The negative terminal of the laser 11 is connected to one end of the switch 12, and the other end of the switch 12 is grounded.

In some examples, an energy transfer component is also included in the laser drive circuitry in the laser projection device. Fig. 9 is a schematic structural diagram of a sixth laser projection apparatus according to an embodiment of the present application. In addition to the laser projection device shown in fig. 1, an energy transfer component is also included in fig. 9. One end of the energy transfer component in the figure is connected with the negative electrode of the laser, when the switch is switched on, a driving signal flows through the laser to drive the laser to emit light, and energy is stored in a parasitic energy storage element formed between the laser and the switch; when the switch is turned off, the energy stored on the parasitic energy storage element is transferred through the energy transfer member.

Fig. 10 is a schematic current flow diagram of a laser projection apparatus provided in the present application. As shown in fig. 10, when the switch is in the on state, current flows from the laser through the switch to ground. When the switch is in the off state, what was originally stored in the parasitic energy storage element is transferred through the energy transfer member. And, the current flowing through the laser is caused to flow to the energy transfer member, accelerating the current drop rate in the laser. Fig. 11 is a schematic current flow diagram of another laser projection apparatus provided in the present application. As shown in fig. 11, when the switch is in the off state, current flows from the laser to the energy transfer member.

In the embodiment shown in the present application, the high-frequency driving circuit, the switch and the energy transfer means are provided in the laser driving circuit. The switch is controlled to be switched on or off by a high-frequency signal generated by the high-frequency driving circuit, and then the laser is driven at high frequency based on the high-frequency signal. And when the switch is turned off, the energy stored in the parasitic energy storage element between the laser and the switch is transferred, so that the current flowing through the laser cannot be turned off due to the energy stored in the parasitic energy storage element in the process of reduction.

In some embodiments, the energy transfer member 13 may include: a resistor and a capacitor. One end of the capacitor is connected with the negative electrode of the laser, the other end of the capacitor is connected with one end of the resistor, and the other end of the resistor is grounded; when the switch is turned off, the energy stored in the parasitic energy storage element is transferred through the resistor and the capacitor.

Fig. 12 is a schematic circuit structure diagram of a second laser driving circuit according to an embodiment of the present disclosure. As shown in fig. 12, the laser 11, the switch 12, the capacitor, the resistor, and the parasitic inductor L are included in the diagram. The positive terminal (VBUS terminal) of the laser 11 is used for receiving a driving signal for driving the laser to emit light. The negative terminal of the laser 11 is connected to one end of the switch 12, and the other end of the switch 12 is grounded. The control end of the switch 12 is used for receiving a high-frequency signal for controlling the on-off of the switch 12.

When the high frequency signal controls the switch 12 to be turned on, the parasitic inductance between the laser 11 and the switch 12 is in a charged state, energy is stored in the parasitic inductance, and the capacitor and the resistor are short-circuited at the time.

When the high frequency signal controls the control switch 12 to turn off, the parasitic inductance stores energy, which hinders the current of the laser 11 from decreasing. However, when a capacitor resistor is added, the parasitic inductive energy is transferred through the capacitor resistor, and the current flows from the laser 11, the capacitor, and the resistor to ground in sequence. The impedance value in the current path in fig. 12 is smaller than the impedance value at the switch-off in the figure, and therefore the discharge speed is increased, i.e., the current drop of the laser 11 is increased. In addition, the laser driving circuit shown in fig. 12 may be used in combination with the circuit configuration shown in fig. 8, that is, in addition to fig. 8, a capacitor and a resistor may be added to constitute an energy transfer means.

Fig. 13 is a schematic diagram of a variation of a laser current according to an embodiment of the present disclosure. In fig. 13, four signals are included, which are a high-frequency signal D for controlling the switch 12, a current signal I1 (which is ideally a signal that does not take into account the existence of parasitic energy storage elements in the circuit) that passes through the laser 11 and varies with the high-frequency signal in an ideal state, a current signal I2 that passes through the laser 11 when the energy transfer means 13 is not applied in an actual state, and a current signal I3 that passes through the laser 11 when the energy transfer means 13 is applied in an actual state. In the figure, the horizontal axis represents time t, and the vertical axis represents the current magnitude of the signal. The values of the high-frequency signal D, the current signal I1, the current signal I2, the current signal I3 and the time t are all larger than 0. In the figure, the high-frequency signal D and the current signal I1 are both in periodic square wave shapes (solid lines); the current signal I2 (solid line) and the current signal I3 (broken line) are curved, and the broken line parallel to the horizontal axis represents the lower limit current value I0 of the laser 11.

In the time period from the time t1 to the time t2, the switch 12 is in a conducting state under the action of the high-frequency signal, and the current loop of the laser 11 can flow from the laser 11 and the switch 12 to the ground in sequence. When the circuit is in an ideal state, i.e., without taking into account the parasitic inductance generated by the laser 11 during high frequency driving, the current through the laser 11 remains constant during this period, i.e., the value of I1 remains constant during the period from time t1 to time t 2. When the energy transfer unit 13 is not added in the actual state, a parasitic inductance exists between the laser 11 and the switch 12, and when the switch is turned on, the parasitic inductance in the current loop is in a charging state, consuming a part of current, so that the current I2 passing through the laser 11 slowly rises. When the energy transfer unit 13 is actually added, a parasitic inductor exists between the laser 11 and the switch, when the switch 12 is turned on, the parasitic inductor in the current loop is in a charging state, a part of current is consumed, and a capacitor resistor is short-circuited but also consumes a part of current, so that the current I3 passing through the laser 11 slowly rises, but the current value of I3 is lower than the current I2. This is because when the switch 12 is turned on, although the resistance of the capacitor is short-circuited, a small amount of energy is stored in the capacitor, so that the current value of the circuit added to the energy transfer part 13 is slowly increased to be less than I3 but I3 is less than I2 in the time period from t1 to t 2.

During the time period from time t2 to time t3, the switch 12 is in the off state under the action of the high frequency signal, and the current in the laser 11 drops to 0. When the circuit is in an ideal state, the current in the laser 11 is reduced to 0, however, since the parasitic inductance between the laser 11 and the switch 12 stores energy when the switch 12 is turned on, when the energy transfer component 13 is not added, the speed of the current I2 in the laser 11 is slowed down due to the parasitic inductance, and when the high-frequency signal controls the moment when the switch 12 is turned on again, namely, at the moment t3, the current I2 in the laser 11 does not drop below the lower limit current I0 of the laser 11, so that the laser 11 always emits light and cannot be turned off. When the energy transfer component 13 is added, the current I3 sequentially flows from the laser 11, the capacitor and the resistor to the ground, and the impedance value in the current path is smaller than that in the path when the switch 12 is turned off, so that the discharge speed is increased, the current I3 of the laser 11 is decreased, and the current I3 is decreased to be less than the lower limit current I0 of the laser 11 before the high-frequency signal controls the switch 12 to be turned on again, so that the laser 11 is ensured to be turned off, and the light emission is stopped.

In the above embodiment, by adding the energy transfer component 13 composed of a capacitor and a resistor to the high-frequency driving circuit, it can be ensured that the current passing through the laser 11 can rapidly drop below the lower limit current of the laser 11 during the discharging process of the laser 11, and the laser 11 can rapidly stop emitting light without being affected by the parasitic inductance in the circuit.

In some embodiments, the energy transfer member 13 includes therein: a diode; the anode of the diode is connected with the cathode of the laser 11; the cathode of the diode is connected with the anode of the laser 11; when the switch 12 is turned off, the energy stored on the parasitic energy storage element is transferred through the diode.

Fig. 14 is a schematic circuit structure diagram of a third laser driving circuit according to an embodiment of the present disclosure. As shown in fig. 14, the laser driving circuit includes: switch 12, diode, and parasitic inductance. The positive terminal (VBUS terminal) of the laser 11 is used for receiving the drive signal. The negative terminal of the laser 11 is connected to one end of the switch 12, and the other end of the switch 12 is grounded. The control end of the switch 12 is used for receiving a high-frequency signal for controlling the on-off of the switch 12. The anode of the diode is connected with the cathode of the laser 11; the cathode of the diode is connected to the anode of the laser 11.

When the high frequency signal controls the switch 12 to be turned on, the parasitic inductance between the laser 11 and the switch 12 is in a charged state, energy is stored in the parasitic inductance, and the diode is short-circuited at this time.

When the high frequency signal control switch 12 is turned off, the parasitic inductance stores energy, which hinders the current of the laser 11 from decreasing. However, when a diode is added, the parasitic inductance energy is transferred through the diode and transferred to the laser 11 itself, and the energy is consumed by driving the laser 11, and then current flows back to the anode of the laser 11 from the anode of the laser 11, the cathode of the laser 11, and the diode in this order. Thus, when the switch 12 is turned off, the laser 11 in the current loop shown in fig. 14 lights up first and then dims down as energy is transferred back to the laser 11, and the rate of current drop is increased by the continued dissipation of the laser 11 itself.

In this embodiment, by providing the diode, the current of the laser 11 can flow back to the laser 11 through the diode during the current drop process, and the consumption of the energy stored in the parasitic inductance is accelerated by the consumption of the laser 11. The situation that the laser 11 cannot be switched off due to the existence of parasitic inductance in the circuit is avoided.

In some embodiments, both of the embodiments of fig. 12 and 14 may be used in combination. Fig. 15 is a schematic circuit structure diagram of a fourth laser driving circuit according to an embodiment of the present disclosure. As shown in fig. 15, the laser driving circuit includes: switch 12, diode, capacitor, resistor, and parasitic inductance. By arranging a diode, a capacitor and a resistor in the circuit, when the switch 12 is switched off, current can flow back to the anode of the laser 11 from the anode of the laser 11, the cathode of the laser 11 and the diode in sequence on one hand; on the other hand, the laser 11, the capacitor and the resistor can flow to the ground in sequence, and the specific principle is the same as that in fig. 12 and 14, and is not described again. In addition, based on the circuit structure shown in fig. 8, a capacitor, a resistor, and a diode may be additionally added in fig. 8 according to the circuit structure shown in fig. 15, which will not be described in detail herein.

In this embodiment, by providing the diode, the capacitor, and the resistor in the energy consumption component, the current of the laser 11 can flow back to the laser 11 through the diode during the current reduction process, and the energy stored in the parasitic inductor is consumed more quickly by the laser 11 itself. On the other hand, the energy stored in the parasitic inductance can be consumed through the external capacitor and the external resistor, and the current reduction speed is increased, that is, the current reduction speed of the laser 11 is increased through the cooperation of the two discharge paths in the embodiment, so that the current of the laser 11 can be ensured to be reduced to be lower than the lower limit current value of the laser 11, and the laser 11 can stop emitting light.

In some examples, a power supply may be further disposed in the laser projection device, and is used to provide power supply signals for the main control circuit, the driving signal generation circuit, and the high-frequency driving circuit in the laser projection device. And the power supply can be connected with a controllable element, so that the path of the power supply for outputting the power supply signal to the outside is switched on or off under the control of the controllable element. In one example, the master control circuit is further configured to control the controllable element to be turned on or off. For example, the main control circuit may control the controllable element to be turned off when detecting that the current passing through the laser is too large, so as to protect the device in the laser projection apparatus from being burned out. In some examples, the power supply may be a conventional flyback, resonant circuit, dc-to-dc converter, or the like, that outputs a multi-path or single-path dc voltage suitable for a laser projection device.

Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.

It will be understood that the present application is not limited to the precise arrangements 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 application is limited only by the appended claims.

Claims

1. A laser projection device, comprising: the laser driving circuit comprises a main control circuit, a laser and a laser driving circuit; the laser driving circuit comprises a driving signal generating circuit, a high-frequency driving circuit and a switch; wherein,

2. A laser projection device as claimed in claim 1,

the master control circuit is connected with the laser and the high-frequency driving circuit and is also used for generating a first control signal and/or a second control signal according to a voltage signal and a current signal of the laser; the first control signal is used for adjusting the driving signal generated by the driving signal generating circuit, and the second control signal is used for adjusting the high-frequency signal generated by the high-frequency driving circuit.

3. The laser projection device of claim 1, further comprising a first sampling circuit;

4. The laser projection device of claim 1, further comprising a second sampling circuit;

5. The laser projection device of claim 1, wherein the lasers include a red laser, a green laser, and a blue laser; the lasers with different colors correspond to the driving signal generating circuits one by one.

6. The laser projection device of claim 1, wherein the master circuit comprises: an algorithm processor and a control processor; wherein,

7. The laser projection device of claim 6, further comprising; a light modulation device; the optical modulation device is connected with the control processor and the laser;

8. The laser projection apparatus of claim 1, wherein the high frequency drive circuit comprises: a high-frequency driving chip;

9. The laser projection apparatus of claim 1, wherein the high frequency drive circuit comprises: the high-frequency signal generator and the high-frequency driving chip;

10. The laser projection device of any of claims 1-9, wherein the laser driver circuit further comprises: an energy transfer member;

11. A laser projection device as claimed in claim 10, wherein the energy transfer component comprises: a resistor and a capacitor;

12. The laser projection device of claim 10, wherein the energy transfer component comprises: a diode;