CN116300284A

CN116300284A - Laser projection device and driving method of light source thereof

Info

Publication number: CN116300284A
Application number: CN202310127831.4A
Authority: CN
Inventors: 张希刚; 高力波
Original assignee: Qingdao Hisense Laser Display Co Ltd
Current assignee: Qingdao Hisense Laser Display Co Ltd
Priority date: 2023-02-16
Filing date: 2023-02-16
Publication date: 2023-06-23

Abstract

The application discloses a laser projection device and a driving method of a light source thereof.A display control circuit in the laser projection device can output a switch control signal to a switch circuit based on the light emitting time sequence of a plurality of second laser light sources, and is used for outputting a first driving signal to a first light source driving circuit and outputting a second driving signal to a second light source driving circuit. The first driving signal is used for driving the first light source driving circuit to output a first driving current to the first laser light source, and the second driving signal is used for driving the second light source driving circuit to output a second driving current. The switch circuit can conduct the second light source driving circuit with one second laser light source in the plurality of second laser light sources under the control of the switch control signal so as to drive the second laser light source to emit light. Since the second light source driving circuit can drive the plurality of second laser light sources to emit light, the structure of the laser projection apparatus is effectively simplified.

Description

Laser projection device and driving method of light source thereof

Technical Field

The present disclosure relates to the field of projection display technologies, and in particular, to a laser projection device and a driving method for a light source thereof.

Background

The laser projection device generally comprises laser light sources of three colors of red, green and blue, and three light source driving circuits corresponding to the laser light sources of the three colors one by one. Each light source driving circuit is used for driving one corresponding laser light source to emit light.

However, the structure of the laser projection apparatus in the related art is complicated.

Disclosure of Invention

The application provides a laser projection device and a driving method of a light source of the laser projection device, which can solve the problem that the structure of the laser projection device is complex in the related technology. The technical scheme is as follows:

in one aspect, there is provided a laser projection apparatus comprising: a display control circuit, a first light source driving circuit, a second light source driving circuit, a switching circuit, a first laser light source, and a plurality of second laser light sources;

the display control circuit is respectively connected with the control end of the switch circuit, the input end of the first light source driving electricity and the input end of the second light source driving circuit, and is used for outputting switch control signals to the switch circuit and outputting first driving signals to the first light source driving circuit and outputting second driving signals to the second light source driving circuit based on the light emitting time sequence of the second laser light sources, wherein the first driving signals and the first driving signals comprise enabling signals and brightness control signals;

The output end of the first light source driving circuit is connected with the first laser light source, and the first light source driving circuit is used for outputting a first driving current to the first laser light source under the driving of the first driving signal so as to drive the first laser light source to emit light;

the output end of the second light source driving circuit is connected with the first end of the switch circuit, and the second light source driving circuit is used for outputting a second driving current under the driving of the second driving signal;

the second end of the switch circuit is connected with a plurality of second laser light sources, and the switch circuit is used for conducting the second light source driving circuit with one of the second laser light sources under the control of the switch control signal so as to drive the second laser light sources to emit light.

In another aspect, there is provided a light source driving method of a laser projection apparatus including: a display control circuit, a first light source driving circuit, a second light source driving circuit, a switching circuit, a first laser light source, and a plurality of second laser light sources; the method comprises the following steps:

the display control circuit outputs a switching control signal to the switching circuit, and outputs a first driving signal to the first light source driving circuit, and outputs a second driving signal to the second light source driving circuit based on light emission timings of the plurality of second laser light sources, the first driving signal and the second driving signal including an enable signal and a brightness control signal;

The first light source driving circuit outputs a first driving current to the first laser light source under the driving of the first driving signal so as to drive the first laser light source to emit light;

the second light source driving circuit outputs a second driving current under the driving of the second driving signal;

the switch circuit is controlled by the switch control signal to conduct the second light source driving circuit with one second laser light source of the plurality of second laser light sources so as to drive the second laser light source to emit light.

In yet another aspect, there is provided a laser projection apparatus including: the light source driving device comprises a memory, a processor and a computer program stored in the memory, wherein the processor realizes the light source driving method according to the aspect when executing the computer program.

In yet another aspect, a computer-readable storage medium having instructions stored therein that are loaded and executed by a processor to implement a method of driving a light source as described in the above aspect is provided.

In a further aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the method of driving a light source as described in the above aspect.

The beneficial effects that this application provided technical scheme brought include at least:

the application provides a laser projection device and a driving method of a light source thereof, wherein a display control circuit in the laser projection device can output a switch control signal to a switch circuit based on the light emitting time sequence of a plurality of second laser light sources, and is used for outputting a first driving signal to a first light source driving circuit and outputting a second driving signal to a second light source driving circuit. The first driving signal is used for driving the first light source driving circuit to output a first driving current to the first laser light source, and the second driving signal is used for driving the second light source driving circuit to output a second driving current. The switch circuit can conduct the second light source driving circuit with one second laser light source in the plurality of second laser light sources under the control of the switch control signal so as to drive the second laser light source to emit light. Since the second light source driving circuit can drive the plurality of second laser light sources to emit light, the structure of the laser projection apparatus is effectively simplified.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a laser projection device according to an embodiment of the present application;

FIG. 2 is a schematic diagram of another laser projection device according to an embodiment of the present disclosure;

FIG. 3 is a schematic view of another laser projection device according to an embodiment of the present disclosure;

fig. 4 is a waveform diagram of output signals of each device in a laser projection apparatus according to an embodiment of the present application;

FIG. 5 is a schematic view of a structure of still another laser projection device according to an embodiment of the present application;

FIG. 6 is a schematic diagram of a laser projection device according to an embodiment of the present disclosure;

fig. 7 is a schematic flow chart of a light source driving method of a laser projection device according to an embodiment of the present application;

fig. 8 is a flowchart of another light source driving method of a laser projection device according to an embodiment of the present disclosure;

fig. 9 is a flowchart of another light source driving method of a laser projection device according to an embodiment of the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a laser projection device according to an embodiment of the present application, and referring to fig. 1, the laser projection device includes: the display control circuit 10, the first light source driving circuit 20, the second light source driving circuit 30, the switching circuit 40, the first laser light source 50, and the plurality of second laser light sources 60. Wherein the first laser light source 50 and the plurality of second laser light sources 60 are different in color from each other. For example, the first laser light source 50 may be a red laser light source, and the plurality of second laser light sources 60 may include a green laser light source and a blue laser light source. Alternatively, the first laser light source 50 may be a green laser light source, and the plurality of second laser light sources 60 may include a red laser light source and a blue laser light source. Still alternatively, the first laser light source 50 may be a blue laser light source and the plurality of second laser light sources 60 may include a red laser light source and a green laser light source.

As shown in fig. 1, the display control circuit 10 is connected to the control terminal C of the switching circuit 40, the input terminal of the first light source driving circuit 20, and the input terminal of the second light source driving circuit 30, respectively. The display control circuit 10 is configured to output a switching control signal to the switching circuit 40 based on the light emission timings of the plurality of second laser light sources 60, and is configured to output a first driving signal to the first light source driving circuit 20 and a second driving signal to the second light source driving circuit 30. Wherein the first driving signal includes an enable signal en_1 and a brightness control signal dimingj1, and the second driving signal includes: an enable signal en_2 and a brightness control signal mming_2.

The output terminal of the first light source driving circuit 20 is connected to a first laser light source 50. The first light source driving circuit 20 is configured to output a first driving current to the first laser light source 50 under the driving of the first driving signal, so as to drive the first laser light source 50 to emit light. An output terminal of the second light source driving circuit 30 is connected to the first terminal 1 of the switching circuit 40. The second light source driving circuit 30 is configured to output a second driving current under the driving of the second driving signal. The second terminal 2 of the switching circuit 40 is connected to a plurality of second laser light sources 60. The switching circuit 40 is configured to switch on the second light source driving circuit 30 and one second laser light source 60 of the plurality of second laser light sources 60 under the control of the switching control signal, so as to drive the second laser light source 60 to emit light.

In this embodiment, after the laser projection device is powered on, the display control circuit 10 of the laser projection device can output a switch control signal to the switch circuit 40 based on the light emitting information of the plurality of laser light sources to control the switch state of the switch circuit 40 (i.e. the on-off states of the first end 1 and the plurality of second laser light sources 60). The switch control signal may be a level signal. The display driving circuit 10 is further capable of providing a first driving signal to the first light source driving circuit 20 and a second driving signal to the second light source driving circuit 30 based on the light emission information, and an enable signal of the two driving signals is used for controlling the operation states of the first light source driving circuit 20 and the second light source driving circuit 30, that is, for controlling whether the two light source driving circuits output driving currents. The brightness control signals in the two driving signals are used for controlling the magnitude of the driving current output by the two light source driving circuits.

The light emission information of the plurality of laser light sources may include duty time and current information of the plurality of laser light sources. The duty time of the plurality of laser light sources may indicate a light emission timing and a light emission period of the plurality of laser light sources within a unit period of time (e.g., 1 second). The current information of the plurality of laser light sources means a rated drive current required when the plurality of laser light sources emit light. The rated drive current of the laser light source means a drive current capable of driving the laser light source to normally emit light.

The first light source driving circuit 20 and the second light source driving circuit 30 can output driving currents after receiving the enable signal and the brightness control signal. The brightness control signal may be a pulse width modulation (pulse width modulation, PWM) signal. The magnitude of the driving current is positively correlated with the duty cycle of the luminance control signal, i.e., the larger the duty cycle of the luminance control signal, the higher the signal value of the driving current. Accordingly, the higher the light emission luminance of the laser light source driven by the driving current.

The switching circuit 40 connected to the second light source driving circuit 30 can turn on the second light source driving circuit 30 and one second laser light source 60 among the plurality of second laser light sources 60 under the control of the switching control signal after receiving the switching control signal. Thus, the driving current outputted from the second light source driving circuit 30 can drive the turned-on one second laser light source 60 to emit light.

That is, the first driving current outputted from the first light source driving circuit 20 can be directly transmitted to the first laser light source 50 to drive the first laser light source 50 to emit light. The second driving current outputted from the second light source driving circuit 30 is transmitted to one of the plurality of second laser light sources 60, which is turned on with the second light source driving circuit 30, under the control of the switching circuit 40.

As a possible implementation, the display control circuit 10 may control the first laser light source 50 and the plurality of second laser light sources 60 to sequentially emit light through the first light source driving circuit 20 and the second light source driving circuit 30. That is, the light emission periods of the first laser light source 50 and the plurality of second laser light sources 60 are not overlapped. For example, the display control circuit 10 may first output the first brightness control signal dimmming_1 and the first enable signal en_1 to the first light source driving circuit 20 to cause the first light source driving circuit 20 to drive the first laser light source 50 to emit light. After the light emission duration of the first laser light source 50 reaches the duty time of the first laser light source 50, the display control circuit 10 outputs the second brightness control signal dimingj2 and the second enable signal en_2 to the second light source driving circuit 30, and outputs the switching control signal to the switching circuit 40, so that the second light source driving circuit 30 drives the plurality of second laser light sources 60 to sequentially emit light.

As another possible implementation, the display control circuit 10 may further output the second brightness control signal dimingj2 and the second enable signal en_2 to the second light source driving circuit 30 and output the switching control signal to the switching circuit 40 when outputting the first brightness control signal dimingj1 and the first enable signal en_1 to the first light source driving circuit 20. At this time, the first laser light source 50 may emit light simultaneously with the second laser light source 60 turned on by one of the plurality of second laser light sources 60. Thus, the light beam emitted from the first laser light source 50 and the light beam emitted from the one second laser light source 60 that is turned on can be mixed into a light beam of a new color. For example, the light beams emitted from the green laser light source and the red laser light source may be mixed into a yellow light beam, and the light beams emitted from the green laser light source and the blue laser light source may be mixed into a cyan light beam.

It will be appreciated that the brightness of the mixed beam of light from two different colour laser sources is higher than the brightness of the beam of light from a single laser source. Therefore, in the process of displaying the projected image by the laser projection device, the display control circuit 10 drives the first laser light source 50 and the second laser light source 60 to emit light simultaneously through the first light source driving circuit 20 and the second light source driving circuit 30, so that the brightness of the projected image projected by the laser projection device is higher, and further, the better display effect of the projected image is ensured.

It can be further understood that, because the switching circuit 40 can control the on-off states of the second light source driving circuit 30 and any one of the plurality of second laser light sources 60 under the control of the switching control signal, the laser projection device can realize the light emission driving of the plurality of laser light sources with different colors only by using the two light source driving circuits. Therefore, the structure of the laser projection device is effectively simplified, and the manufacturing cost of the laser projection device is reduced.

In summary, the embodiments of the present application provide a laser projection device, where a display control circuit in the laser projection device is capable of outputting a switch control signal to a switch circuit based on a light emission timing of a plurality of second laser light sources, and is configured to output a first driving signal to a first light source driving circuit and output a second driving signal to a second light source driving circuit. The first driving signal is used for driving the first light source driving circuit to output a first driving current to the first laser light source, and the second driving signal is used for driving the second light source driving circuit to output a second driving current. The switch circuit can conduct the second light source driving circuit with one second laser light source in the plurality of second laser light sources under the control of the switch control signal so as to drive the second laser light source to emit light. Since the second light source driving circuit can drive the plurality of second laser light sources to emit light, the structure of the laser projection apparatus is effectively simplified.

In addition, the display control circuit can output driving signals to the first light source driving circuit and the second light source driving circuit respectively, so that the flexibility of driving the light source of the laser projection device is effectively improved.

Alternatively, the display control circuit 10 may include a digital light processing (digital light processing, DLP) chip. Alternatively, the display control circuit 10 may include a micro control unit (microcontroller unit, MCU), which may also be referred to as a single chip microcomputer. Still alternatively, the display control circuit 10 may include a system on chip (SoC). The first light source driving circuit 20 and the second light source driving circuit 30 may each include a constant current driving integrated circuit (integrated circuit, IC), which may also be referred to as a constant current driving chip.

Fig. 2 is a schematic structural diagram of another laser projection device according to an embodiment of the present application, and referring to fig. 2, the laser projection device may further include: a power supply circuit 70. The output terminals of the power supply circuit 70 are connected to the input terminals of the first light source driving circuit 20 and the second light source driving circuit 30, respectively. The power supply circuit 70 is configured to provide a first driving voltage vcc_1 to the first light source driving circuit 20 and a second driving voltage vcc_2 to the second light source driving circuit 30. Thus, the first light source driving circuit 20 may be caused to output the first driving current under the driving of the first driving voltage vcc_1, and the second light source driving circuit 30 may be caused to output the second driving current under the driving of the second driving voltage vcc_2. The voltage value of the first driving voltage vcc_1 and the voltage value of the second driving voltage vcc_2 may be the same.

Alternatively, the power circuit 70 may include an alternating current-direct current (AD-DC) converter.

Optionally, referring to fig. 3, the switching circuit 40 may include: a plurality of first transistors M1 in one-to-one correspondence with the plurality of second laser light sources 60.

As shown in fig. 3, the gate (G) of each first transistor M1 is connected to the display control circuit 10 as the control terminal C of the switching circuit 40, the first pole of each first transistor M1 is connected to the output terminal of the second light source driving circuit 30 as the first terminal 1 of the switching circuit 40, and the second pole of each first transistor M1 is connected to a corresponding one of the second laser light sources 60 as the second terminal 2 of the switching circuit 40.

Alternatively, referring to fig. 3, the plurality of first transistors M1 may be P-type metal oxide semiconductor (metal oxide semiconductor, MOS) transistors. The first poles of the first transistors M1 may be sources (S), and the second poles of the first transistors M1 may be drains (D).

In this embodiment of the present application, after the display control circuit 10 is powered on (may also be referred to as initialization), the light emitting information of the plurality of laser light sources in the projection process of the laser projection device can be obtained. Wherein the light emission information may include duty time and current information of the plurality of laser light sources. The duty time of the plurality of laser light sources may indicate a light emission timing and a light emission duration of the plurality of laser light sources. The light emission information of the plurality of laser light sources may be stored in advance in the display control circuit 10. Alternatively, the laser projection device may further comprise a memory. The light emission information of the plurality of laser light sources may be acquired from the memory after the display control circuit 10 is powered on.

The display control circuit 10 can output a switching control signal of an active level to the gate G of the first transistor M1 corresponding to the target second laser light source 60 in the switching circuit 40, a switching control signal of an inactive level to the gate G of the first transistor M1 corresponding to the other second laser light source 60 than the target second laser light source 60 in the plurality of second laser light sources 60, and a luminance control signal corresponding to the target second laser light source 60 to the second light source driving circuit 30 based on the light emission information of the plurality of laser light sources. The active level of the switch control signal may be low with respect to the inactive level. The target second laser light source 60 may be the second laser light source 60 that the display control circuit 10 determines to be currently required to be lit based on the light emission timings of the plurality of laser light sources.

In the embodiment of the present application, the second light source driving circuit 30 can transmit the second driving current to the sources S of the plurality of first transistors M1 based on the brightness control signal corresponding to the target second laser light source 60. After receiving the switch control signal of the active level, the gate G of the first transistor M1 corresponding to the target second laser light source 60 can turn on the source S and the drain D thereof. Thereby, the second driving current output from the second light source driving circuit 30 can be made to drive the target second laser light source 60 to emit light. At this time, the other second laser light sources 60 among the plurality of second laser light sources 60 except for the target second laser light source 60 do not emit light.

When the target second laser light source 60 needs to be turned off, the display control circuit 10 may output a switching control signal of an inactive level to the gate G of the first transistor M1 corresponding to the target second laser light source 60, so that the source S and the drain D of the first transistor M1 are turned off. Thereby, the second driving current output from the second light source driving circuit 30 can be stopped from driving the target second laser light source 60 to emit light.

The on-time of the first transistor M1 corresponding to the target second laser light source 60 may be the duty time of the target second laser light source 60. After determining that the on-time of the first transistor M1 corresponding to the target second laser light source 60 reaches the duty time of the target second laser light source 60, the display control circuit 10 may output a switching control signal of an inactive level to the gate G of the first transistor M1. The display control circuit 10 may output the switching control signal of the active level to the gate electrode G of the first transistor M1 corresponding to the other second laser light source 60 (i.e., the new target second laser light source 60) among the plurality of second laser light sources 60, and output the luminance control signal corresponding to the other second laser light source 60 to the light source driving circuit 20.

Alternatively, the display control circuit 10 may output the switching control signal of the active level to the gate G of the first transistor M1 corresponding to another second laser light source 60 of the plurality of second laser light sources 60 after the duration of outputting the switching control signal of the inactive level to the gate G of the first transistor M1 corresponding to the target second laser light source 60 reaches the target duration t. The target duration may be determined based on the off duration of the first transistor M1 corresponding to the target second laser light source 60, for example, the target duration may be greater than or equal to the off duration. Also, the turn-off periods of the first transistors M1 corresponding to the plurality of second laser light sources 60 may be the same.

Alternatively, referring to fig. 3, the first laser light source 50 may be a green laser light source 50_g, and the plurality of second laser light sources 60 may include a red laser light source 60_r and a blue laser light source 60_b. Referring to fig. 4, after the display control circuit 10 is powered on, an enable signal en_1 of an active level and a brightness control signal dimingj1 corresponding to the green laser light source 50_g may be output to the first light source driving circuit 20. The first light source driving circuit 20 can further output a first driving current dc_1 to the green laser light source 50_g to drive the green laser light source 50_g to emit light. At this time, the red laser light source 60_r and the blue laser light source 60_b do not emit light. As shown in fig. 4, the active level of the enable signal en_1 may be at a high level with respect to the inactive level.

After the light emission period of the green laser light source 50_g reaches the Duty time Duty1 corresponding to the green laser light source 50_g, the display control circuit 10 can output the enable signal en_1 of the inactive level to the first light source driving circuit 20 and stop outputting the luminance control signal diming_1 corresponding to the green laser light source 50_g to the first light source driving circuit 20. At this time, the green laser light source 50_g stops emitting light. After determining that the period of time for which the green laser light source 50_g stops emitting reaches the target period of time t, the display control circuit 10 may output the enable signal en_2 of the active level and the brightness control signal dimmming_2 corresponding to the red laser light source 60_r to the second light source driving circuit 30, and output the switch control signal drvm_1 of the active level to the gate G of the first transistor M1 corresponding to the red laser light source 60_r. At this time, the first transistor M1 can turn on the second light source driving circuit 30 and the red laser light source 60_r. The second driving current dc_2 outputted from the second light source driving circuit 30 can drive the red laser light source 60_r to emit light.

After the light emission duration of the red laser light source 60_r reaches the Duty time Duty2 corresponding to the red laser light source 60_r, the display control circuit 10 may output the switching control signal drvm_1 of the inactive level to the gate G of the first transistor M1 corresponding to the red laser light source 60_r. At this time, the red laser light source 60_r stops emitting light. After determining that the period of time for which the red laser light source 60_r stops emitting reaches the target period of time, the display control circuit 10 may output the switching control signal drvm_2 of the active level to the gate G of the first transistor M1 corresponding to the blue laser light source 60_b, and output the brightness control signal dimingj2 corresponding to the blue laser light source 60_b to the second light source driving circuit 30. At this time, the first transistor M1 corresponding to the blue laser light source 60_b can turn on the second light source driving circuit 30 and the blue laser light source 60_b under the control of the switching control signal drvm_2. The second driving current dc_3 outputted from the second light source driving circuit 30 can drive the blue laser light source 60_b to emit light.

After the light emission duration of the blue laser light source 60_b reaches the Duty time Duty3 corresponding to the blue laser light source 60_b, the display control circuit 10 may output the switching control signal drvm_2 of the inactive level to the gate G of the first transistor M1 corresponding to the blue laser light source 60_b. At this time, the blue laser light source 60_b stops emitting light.

In the embodiment of the present application, if the brightness of the projected image projected by the laser projection device needs to be increased, the first light source driving circuit 20 and the second light source driving circuit 30 can output the driving current at the same time, so that the first laser light source 50 and one second laser light source 60 of the plurality of second laser light sources 60 emit light at the same time. With continued reference to fig. 4, after determining that the period of time during which the blue laser light source 60_b stops emitting reaches the target period of time, the display control circuit 10 may output the enable signal en_1 of the active level and the brightness control signal dimingj1 corresponding to the green laser light source 50_g to the first light source driving circuit 20, output the enable signal en_2 of the active level and the brightness control signal dimingj2 corresponding to the red laser light source 60_r to the second light source driving circuit 30, and output the switching control signal drvm_1 of the active level to the gate G of the first transistor M1 corresponding to the red laser light source 60_r in the switching circuit 40. At this time, the green laser light source 50_g and the red laser light source 60_r can emit light simultaneously. For example, the color of the mixed light beam emitted from the green laser light source 50_g and the red laser light source 60_r may be yellow.

After the light emission periods of the green laser light source 50_g and the red laser light source 60_r reach the preset Duty time Duty4, the display control circuit 10 may output the switching control signal drvm_1 of the inactive level to the gate G of the first transistor M1 corresponding to the red laser light source 60_r and stop outputting the enable signal en_1 of the active level to the first light source driving circuit 20. At this time, the red laser light source 60_r and the green laser light source 50_g stop emitting light.

After determining that the time period for which the red laser light source 60_r and the green laser light source 50_g stop emitting light reaches the target time period, the display control circuit 10 may output the enable signal en_1 of the active level and the luminance control signal dimingj1 corresponding to the green laser light source 50_g to the first light source driving circuit 20, output the enable signal en_2 of the active level and the luminance control signal dimingj2 corresponding to the blue laser light source 60_b to the second light source driving circuit 30, and output the switching control signal drvm_2 of the active level to the gate G of the first transistor M1 corresponding to the blue laser light source 60_b in the switching circuit 40. At this time, the green laser light source 50_g and the blue laser light source 60_b can emit light simultaneously. For example, the color of the mixed beam emitted from the green laser light source 50_g and the blue laser light source 60_b may be cyan.

After the light emission periods of the green laser light source 50_g and the blue laser light source 60_b reach the preset Duty time Duty5, the display control circuit 10 may output the switching control signal drvm_2 of the inactive level to the gate G of the first transistor M1 corresponding to the blue laser light source 60_b and stop outputting the enable signal en_1 of the active level to the first light source driving circuit 20. At this time, the blue laser light source 60_b and the green laser light source 50_g stop emitting light.

Optionally, as shown in fig. 5, the laser projection device may further include: a first current regulation circuit 80 corresponding to the first light source driving circuit 20, and a second current regulation circuit 90 corresponding to the second light source driving circuit 30. Referring to fig. 5, the first current adjusting circuit 80 is connected to the output terminal of the first light source driving circuit 20 and the first laser light source 50, respectively. The first current adjusting circuit 80 is used for adjusting the first driving current dc_1 outputted from the first light source driving circuit 20.

The second current adjusting circuit 90 is connected to the output terminal of the second light source driving circuit 30, the first terminal 1 of the switching circuit 40, and the plurality of second laser light sources 60, respectively. The second current adjusting circuit 90 is used for adjusting the second driving current dc_2 outputted from the second light source driving circuit 30.

It will be appreciated that the driving currents output by the first light source driving circuit 20 and the second light source driving circuit 30 may be different from the driving current flowing through the laser light source, that is, the driving current received by the laser light source is not consistent with the rated driving current required when the laser light source emits light. Therefore, the first current adjusting circuit 80 in the laser projection device can adjust the magnitude of the first driving current dc_1 outputted by the first light source driving circuit 20 so that the first driving current dc_1 actually flowing through the first laser light source 50 is consistent with the rated driving current required by the first laser light source 60. The second current adjusting circuit 90 may adjust the magnitude of the second driving current dc_2 outputted from the second light source driving circuit 30 so that the second driving current dc_2 actually flowing through the second laser light source 60 is consistent with the rated driving current required by the second laser light source 60. Therefore, the plurality of laser light sources can be ensured to normally emit light, and further, the good display effect of the projected image projected by the laser projection device is ensured.

Alternatively, as shown in fig. 5, the first current adjusting circuit 80 may include: a first inductor L1, a first diode D1 and a second transistor M2.

One end of the first inductor L1 is connected to the output end of the first light source driving circuit 20 and the first end of the first diode D1, respectively, and the other end of the first inductor L1 is connected to one end of the first laser light source 50. The second terminal of the first diode D1 is connected to the other terminal of the first laser light source 50 and the first pole of the second transistor M2, respectively. The gate G of the second transistor M2 is connected to the output terminal of the first light source driving circuit 20, and the second pole of the second transistor M2 is connected to the ground terminal GND.

With continued reference to fig. 5, the second current regulation circuit 90 may include: a second inductor L2, a second diode D2 and a third transistor M3. One end of the second inductor L2 is connected to the output end of the second light source driving circuit 30 and the first end of the second diode D2, respectively, and the other end of the second inductor L2 is connected to the first end 1 of the switching circuit 40. The second end of the second diode D2 is connected to the plurality of second laser light sources 60 and the first pole of the third transistor M3, respectively. The gate G of the third transistor M3 is connected to the output terminal of the second light source driving circuit 30, and the second pole of the third transistor M3 is connected to the ground terminal GND.

Alternatively, referring to fig. 5, the first ends of the first and second diodes D1 and D2 may be cathodes, and the second ends of the first and second diodes D1 and D2 may be anodes. The second transistor M2 and the third transistor M3 may be P-type MOS transistors. The first poles of the second transistor M2 and the third transistor M3 may be both sources S, and the second poles of the second transistor M2 and the third transistor M3 may be both drains D.

Since the first current adjusting circuit 80 and the second current adjusting circuit 90 have the same structure, the operation principle of the two current adjusting circuits will be described below by taking the first current adjusting circuit 80 as an example.

In the embodiment of the present application, the first light source driving circuit 20 may output the driving control signal drv_1 to the gate G of the second transistor M2 when outputting the first driving current dc_1 to the first laser light source 50. The driving control signal drv_1 may be a PWM signal. Based ON the principle of PWM, the PWM signal is output in the form of a periodic pulse train in an ON (ON) state or an OFF (OFF) state. The pulse in the on state is at a high level, and the off state corresponds to no pulse output.

When the driving control signal drv_1 outputted from the first light source driving circuit 20 is outputted to the gate G of the second transistor M2 in a pulse-free form, the source S and the drain D of the second transistor M2 can be turned on. At this time, the first diode D1 is in an off state. Thereby, the first light source driving circuit 20 can be made conductive to the ground GND so that the first laser light source 50 is in a light emitting state.

It is understood that, when the output terminal of the first light source driving circuit 20 is connected to the ground terminal GND, the first inductor L1 can store a part of the first driving current dc_1 outputted from the first light source driving circuit 20 in the form of electric energy. That is, when the second transistor M2 is in the on state, the first inductor L1 is in the charged state.

When the driving control signal drv_1 outputted from the first light source driving circuit 20 is pulsed to the gate electrode G of the second transistor M2, the source electrode S and the drain electrode D of the second transistor M2 are turned off. At this time, the first diode D1 is in a conductive state, and the first inductor L1 is in a discharge state. Accordingly, when the second transistor M2 is in the off state, the electric energy emitted from the first inductor L1 can continue to drive the first laser light source 50 to emit light. Thereby, the stability of the light emission of the first laser light source 50 can be ensured.

It can be understood that the first light source driving circuit 20 can change the on-time of the second transistor M2 by adjusting the duty ratio of the driving control signal drv_1 outputted therefrom. When the duty ratio of the driving control signal drv_1 in a unit time (for example, 1 second) is relatively small, the on-time of the second transistor M2 in the unit time is relatively long, and the first driving current dc_1 flowing through the first laser light source 50 is also relatively large. When the duty ratio of the driving control signal drv_1 in the unit time is relatively large, the turn-off duration (i.e., the turn-on duration) of the second transistor M2 in the unit time is relatively long, and the first driving current dc_1 flowing through the first laser light source 50 is relatively small. Therefore, the adjustment of the first driving current dc_1 flowing through the first laser light source 50 can be realized, so that the difference between the first driving current dc_1 flowing through the first laser light source 50 and the rated driving current of the first laser light source 50 is smaller, and the light emitting effect of the first laser light source 50 is ensured.

Optionally, as shown in fig. 5, the laser projection device may further include: a first sampling resistor R1 and a second sampling resistor R2. One end of the first sampling resistor R1 is connected to the output end and the feedback end of the first light source driving circuit 20, respectively. The other end of the first sampling resistor R1 is connected to the ground GND. One end of the second sampling resistor R2 is connected to the output end and the feedback end of the second light source driving circuit 30, respectively, and the other end of the second sampling resistor R2 is connected to the ground GND.

In the embodiment of the present application, when the output end (i.e., the end outputting the first driving current dc_1) of the first light source driving circuit 20 is connected to the ground GND, the first sampling resistor R1 is capable of sampling the driving first driving current dc_1 flowing through the first laser light source 50. The first light source driving circuit 20 can receive the driving current sampled by the first sampling resistor R1 through its feedback terminal. The first light source driving circuit 20 may store therein a rated driving current of the first laser light source 50 in advance. The first light source driving circuit 20 can adjust the duty ratio of the driving control signal drv_1 outputted based on the sampled driving current and the rated driving current stored in advance.

For example, when the first light source driving circuit 20 determines that the sampled driving current is smaller than the rated driving current, the duty ratio of the driving control signal drv_1 outputted therefrom may be reduced, so that the on-time of the second transistor M2 may be increased, and thus the current value of the first driving current dc_1 flowing through the first laser light source 50 may be increased. When the first light source driving circuit 20 determines that the sampled driving current is greater than the rated driving current, the duty ratio of the driving control signal drv_1 outputted therefrom may be increased, thereby reducing the on-time of the second transistor M2, and further reducing the current value of the first driving current dc_1 flowing through the first laser light source 50.

The second light source driving circuit 30 may adjust the duty ratio of the driving control signal drv_2 outputted based on the driving current sampled by the second sampling resistor R2, and further adjust the current value of the second driving current dc_2 flowing through the second laser light source 60.

Fig. 6 is a schematic structural view of a projection apparatus in the related art. Referring to fig. 6, the projection apparatus includes: the display control circuit 01 includes a plurality of light sources having different colors, a light source driving circuit 03 corresponding to the plurality of light sources, and a current adjusting circuit 04 corresponding to the plurality of light sources. Wherein. Each current regulation circuit 04 includes: a third inductor L3, a third diode D3, and a fourth transistor M4. Alternatively, as shown in fig. 5, the plurality of light sources may include: red light source 02_r, green light source 02_g, and blue light source 02_b.

The circuit formed by each light source, the light source driving circuit 03 corresponding to the light source and the current adjusting circuit 04 may be called a BUCK (BUCK) topology circuit. And, the BUCK topology circuit can be integrated on a light source driving board of the projection device.

As shown in fig. 6, the projection apparatus may further include sampling resistors R3 connected to the plurality of current adjusting circuits 04 in one-to-one correspondence. The light source driving circuit 03 can adjust the driving current flowing through the light source by the driving current obtained by sampling the sampling resistor R3.

When the display control circuit 01 outputs the brightness control signal dimmming and the enable signal EN of the active level to the light source driving circuit 03 corresponding to the red light source 02_r, the light source driving circuit 02 can output the driving current to the red light source 02_r through the third inductor L3 and the driving control signal drvm_3 to the gate G of the fourth transistor M4. The third transistor M3 can be switched in an on-off state under the control of the driving control signal drvm_3, so that the light source driving circuit 03 can drive the red light source 02_r to emit light. The light emission principle of the green light source 02_g and the blue light source 02_b is the same as the light emission principle of the red light source 02_r, and will not be described again.

It can be understood that, when the light sources emit light, the fourth transistors M4 in the current adjusting circuit 04 corresponding to the light sources are in a high-speed switching state. When the plurality of fourth transistors M4 are frequently switched in the switching state, a large amount of electromagnetic radiation is generated, thereby causing electromagnetic compatibility (electromagnetic compatibility, EMC) problems. The projection device needs to be provided with a magnetic ring or other devices capable of shielding electromagnetic radiation to reduce EMC problems. And, the plurality of fourth transistors M4 generate a large amount of heat during the switching process and the on process. The projection equipment needs to be provided with a radiator for cooling, so that the projection equipment in the related art is complex in structure and high in cost.

Referring to fig. 5, a projection apparatus in the related art needs to be provided with a plurality of light source driving circuits 03 and energy storage inductors L3. The plurality of light source driving circuits 03 and the third inductor L3 not only increase the cost of the projection apparatus, but also increase the area and the structural complexity of the light source driving board of the projection apparatus.

In the laser projection apparatus provided in the present application, the light emission driving of the plurality of laser light sources can be achieved only by two light source driving circuits and one switching circuit 40. In addition, the laser projection equipment can realize the adjustment of the driving currents output by the two light source driving circuits only by arranging two current adjusting circuits. Therefore, the structure of the light source driving plate in the laser projection device is effectively simplified, and the cost of the laser projection device is reduced. In addition, the light source driving plate of the laser projection device has a simpler structure and smaller area, so that the integrated arrangement of the light source driving plate and the light source plate (such as a laser) can be facilitated, and the miniaturization of the laser projection device is further realized.

It is also understood that in the laser projection device provided in the present application, only the second transistor M2 and the third transistor M3 are in a high-speed switching state. Therefore, heat and electromagnetic radiation generated by the current regulating circuit in the process of regulating the driving current output by the light source driving circuit can be effectively reduced. Therefore, the laser projection device does not need to be provided with a radiator and a device for shielding electromagnetic radiation, so that the structure of the laser projection device is further simplified, and the cost of the laser projection device is further reduced.

Fig. 7 is a flowchart of a light source driving method of a laser projection apparatus according to an embodiment of the present application. The method may be applied to a laser projection device, such as the laser projection device shown in fig. 1, with reference to fig. 1, comprising: the display control circuit 10, the first light source driving circuit 20, the second light source driving circuit 30, the switching circuit 40, the first laser light source 50, and the plurality of second laser light sources 60. Referring to fig. 7, the method includes:

step 101, the display control circuit outputs a switch control signal to the switch circuit, and outputs a first drive signal to the first light source drive circuit, and outputs a second drive signal to the second light source drive circuit based on the light emission timings of the plurality of second laser light sources.

Wherein the first and second driving signals include an enable signal and a brightness control signal. After the laser projection device is powered on, the display control circuit 10 of the laser projection device can output a switch control signal to the switch circuit 40 based on the light emitting information of the plurality of laser light sources to control the switch state (i.e., the on-off states of the first end 1 and the plurality of second laser light sources 60) of the switch circuit 40. The switch control signal may be a level signal. The display driving circuit 10 is further capable of providing a first driving signal to the first light source driving circuit 20 and a second driving signal to the second light source driving circuit 30 based on the light emission information, and enabling signals in the first driving signal and the second driving signal are used for controlling the operation states of the first light source driving circuit 20 and the second light source driving circuit 30, that is, for controlling whether the light source driving circuit outputs a driving current. The brightness control signals in the first driving signal and the second driving signal are used for controlling the magnitude of the driving current output by the light source driving circuit.

Step 102, the first light source driving circuit outputs a first driving current to the first laser light source under the driving of the first driving signal, so as to drive the first laser light source to emit light.

The brightness control signal received by the first light source driving circuit 20 may be a PWM signal. The magnitude of the first driving current may be positively correlated with the duty ratio of the luminance control signal, i.e., the larger the duty ratio of the luminance control signal, the higher the signal value of the first driving current. Accordingly, the higher the light emission luminance of the first laser light source 50 driven by the first driving current.

Step 103, the second light source driving circuit outputs a second driving current under the driving of the second driving signal.

In the embodiment of the present application, the second light source driving circuit 30 is capable of outputting the second driving current based on the luminance control signal in the driving signal after receiving the second driving signal.

Step 104, the switching circuit is controlled by the switching control signal to conduct the second light source driving circuit with one of the plurality of second laser light sources so as to drive the second laser light sources to emit light.

In the embodiment of the present application, after receiving the switching control signal, the switching circuit 40 connected to the second light source driving circuit 30 can conduct the second light source driving circuit 30 with one second laser light source 60 of the plurality of second laser light sources 60 under the control of the switching control signal. Thus, the second driving current outputted from the second light source driving circuit 30 can drive the turned-on one second laser light source 60 to emit light.

It is understood that the first driving current output by the first light source driving circuit 20 can be directly transmitted to the first laser light source 50 to drive the first laser light source 50 to emit light. The second driving current outputted from the second light source driving circuit 30 is transmitted to one of the plurality of second laser light sources 60, which is turned on with the second light source driving circuit 30, under the control of the switching circuit 40.

Wherein the light emission periods of adjacent two second laser light sources 60 may be spaced apart by a target period of time. The target time period may be determined based on a switching time period of the switching circuit 40. That is, the second light source driving circuit 30 may drive only one second laser light source 60 of the plurality of second laser light sources 60 to emit light in the same period, that is, the emission periods of the plurality of second laser light sources 60 are not overlapped. The duration of the light-emitting periods of the plurality of second laser light sources may be the same or different.

It will be appreciated that the switching circuit 40 requires a certain period of time when switching the paths between the second light source driving circuit 30 and the plurality of second laser light sources 60. By spacing the conduction periods of the adjacent two second laser light sources 60 and the second light source driving circuit 30 by the target period, it is possible to avoid the second light source driving circuit 30 from driving the two second laser light sources 60 to emit light at the same timing. This can effectively ensure the emission purity of the plurality of second laser light sources 60.

As a first possible implementation, the emission periods of the first laser light source 50 and the plurality of second laser light sources 60 do not overlap each other. In this embodiment, the display control circuit 10 can control the first laser light source 50 and the plurality of second laser light sources 60 to sequentially emit light by the first light source driving circuit 20 and the second light source driving circuit 30. For example, the display control circuit 10 may first drive the first laser light source 50 to emit light by the first light source driving circuit 20. After the light emission duration of the first laser light source 50 reaches the duty time corresponding to the first laser light source 50, the display control circuit 10 may drive the plurality of second laser light sources 60 to sequentially emit light through the second light source driving circuit 30.

As a second possible implementation, the first laser light source 50 overlaps with the emission period of one second laser light source 60 of the plurality of second laser light sources 60, and the emission periods of the plurality of second laser light sources 60 do not overlap with each other. In this embodiment, the display control circuit 10 controls the first laser light source 50 to emit light by the first light source driving circuit 20, and drives the plurality of second laser light sources 60 to emit light sequentially by the second light source driving circuit 30 and the switching circuit 40. Thus, the light beam emitted from the first laser light source 50 and the light beam emitted from one of the plurality of second laser light sources 60 can be mixed into a light beam of a new color.

Referring to fig. 4, the first laser light source 50 may be a green laser light source 50_g, and the plurality of second laser light sources 60 may include a red laser light source 60_r and a blue laser light source 60_b. The switching circuit 40 may include two first transistors M1 connected to the two second laser light sources 60 in one-to-one correspondence. The driving method of the three laser light sources is explained below. Referring to fig. 8, the driving method may include:

step S1, powering on and starting the laser projection equipment, and initializing a display control circuit.

The user can control the laser projection device to be electrified and started in a remote control mode or a mode of pressing a switch key of the laser projection device. After the laser projection device is powered on, the display control circuit 10 may be initialized. In this case, the display control circuit 10 may acquire the light emission information of the plurality of laser light sources in the laser projection apparatus during the initialization process.

Step S2, the display control circuit outputs a first driving signal to the first light source driving circuit.

The first driving signal includes an enable signal of an active level and a brightness control signal corresponding to the green laser light source 50_g. The first light source driving circuit 20 can output a first driving current to the green laser light source 50_b under the driving of the driving signal to drive the green laser light source 50_g to emit light. At this time, the level of the enable signal output from the display control circuit 10 to the second light source driving circuit 30 is an inactive level, and the red laser light source 60_r and the blue laser light source 60_b do not emit light.

And S3, detecting whether the light emitting duration of the green laser source reaches a first duration by the display control circuit.

The first duration may be a duty time of the green laser light source 50_g. If the display control circuit 10 determines that the light emission period of the green laser light source 50_g reaches the first period, the following step S4 may be performed. If the display control circuit 10 determines that the light emission period of the green laser light source 50_g does not reach the first period, the first light source driving circuit 20 may continue to drive the green laser light source 50_g to emit light.

And S4, the display control circuit outputs an enable signal of an invalid level to the first light source driving circuit.

After determining that the light emission duration of the green laser light source 50_g reaches the first duration, the display control circuit 10 outputs an enable signal of an inactive level to the first light source driving circuit 20, so that the first light source driving circuit 20 stops driving the green laser light source 50_g to emit light.

And S5, the display control circuit outputs a second driving signal to the second light source driving circuit and outputs a switch control signal of an effective level to the first transistor corresponding to the red laser light source.

The driving signal may include an enable signal of an active level and a brightness control signal corresponding to the red laser light source 60_r. The second light source driving circuit 30 can output a second driving current after receiving the driving signal. After receiving the switching control signal of the active level, the first transistor M1 corresponding to the red laser light source 60_r can turn on the second light source driving circuit 30 and the red laser light source 60_r under the control of the switching control signal of the active level. At this time, the red laser light source 60_r can emit light under the drive of the second drive current, and the green laser light source 50_g and the blue laser light source 60_b do not emit light.

Alternatively, the display control circuit 10 may output the second driving signal to the second light source driving circuit 30 after detecting that the period of time during which it outputs the enable signal of the inactive level to the first light source driving circuit 20 reaches the first target period of time. The first target period may be a period during which the first light source driving circuit 20 completely stops outputting the first driving current after receiving the enable signal of the inactive level. Thereby, the emission purity of the red laser light source 60_r can be ensured.

And S6, the display control circuit detects whether the light emitting duration of the red laser source reaches a second duration.

The second duration may be a duty time of the red laser light source 60_r. If the display control circuit 10 determines that the light emission period of the red laser light source 60_r reaches the second period, the following step S7 may be performed. If the display control circuit 10 determines that the light emission period of the red laser light source 60_r does not reach the second period, the second light source driving circuit 30 may continue to drive the red laser light source 60_r to emit light.

And S7, the display control circuit outputs a switching control signal with invalid level to the first transistor corresponding to the red laser light source.

After determining that the light emission period of the red laser light source 60_r reaches the second period, the display control circuit 10 outputs a switching control signal of an inactive level to the first transistor M1 corresponding to the red laser light source 60_r. The first transistor M1 can turn off the second light source driving circuit 30 and the red laser light source 60_r under the control of the switching control signal of the inactive level. After the first transistor M1 is completely turned off, the red laser light source 60_r stops emitting light.

And S8, the display control circuit outputs a third driving signal to the second light source driving circuit and outputs a switch control signal of an effective level to the first transistor corresponding to the blue laser light source.

Wherein the third driving signal includes an enable signal of an active level and a brightness control signal corresponding to the blue laser light source 60_b. The second light source driving circuit 30 can output a second driving current after receiving the second driving signal. The current value of the second driving current outputted by the second light source driving circuit 30 based on the second driving signal may be the same as or different from the current value of the second driving current outputted by the third driving signal. After receiving the switching control signal of the active level, the first transistor M1 corresponding to the blue laser light source 60_b can turn on the second light source driving circuit 30 and the blue laser light source 60_b under the control of the switching control signal of the active level. At this time, the blue laser light source 60_b can emit light under the drive of the second drive current, and the green laser light source 50_g and the red laser light source 60_r do not emit light.

Alternatively, the display control circuit 10 may output the third driving signal to the second light source driving circuit 30 after detecting that the off-time period of the second light source driving circuit 30 and the red laser light source 60_r reaches the second target time period. The second target duration may be determined based on the off duration of the first transistor M1. For example, the second target period may be greater than or equal to the off period of the first transistor M1.

Step S9, the display control circuit detects whether the light emitting duration of the blue laser source reaches a third duration.

The third duration may be a duty time of the blue laser light source 60_b. If the display control circuit 10 determines that the light emission period of the blue laser light source 60_b reaches the third period, the following step S10 may be performed. If the display control circuit 10 determines that the light emission period of the blue laser light source 60_b does not reach the third period, the second light source driving circuit 30 may continue to drive the blue laser light source 60_b to emit light.

Step S10, the display control circuit outputs a switching control signal of an invalid level to a first transistor corresponding to the blue laser light source.

After determining that the light emission period of the blue laser light source 60_b reaches the third period, the display control circuit 10 outputs a switching control signal of an inactive level to the first transistor M1 corresponding to the blue laser light source 60_b. The first transistor M1 can turn off the second light source driving circuit 30 and the blue laser light source 60_b under the control of the switching control signal of the inactive level. After the first transistor M1 is completely turned off, the blue laser light source 60_b stops emitting light.

Optionally, referring to fig. 9, the driving method of the three laser light sources may further include:

Step S11, the display control circuit outputs a first driving signal to the first light source driving circuit, outputs a second driving signal to the second light source driving circuit, and outputs a switch control signal of an effective level to the first transistor corresponding to the red laser light source.

The first light source driving circuit 20 can directly drive the green laser light source 50_g to emit light under the driving of the first driving signal. The second light source driving circuit 30 can drive the red laser light source 60_r to emit light by the first transistor M1 corresponding to the red laser light source 60_r, under the driving of the second driving signal. At this time, the green laser light source 50_g and the red laser light source 60_r can emit light simultaneously. The light beams emitted by the two laser light sources are mixed light beams. For example, the color of the mixed beam may be yellow.

Step S12, the display control circuit detects whether the light emitting duration of the green laser light source and the red laser light source reaches a fourth duration.

The fourth duration may be determined based on the duty time of the light beam obtained by mixing the green laser light source 50_g and the red laser light source 60_r. The display control circuit 10 may execute step 213 described below if detecting that the light emission periods of the green laser light source 50_g and the red laser light source 60_r reach the fourth period. If the display control circuit 10 detects that the light emission periods of the green laser light source 50_g and the red laser light source 60_r do not reach the fourth period, the green laser light source 50_g and the red laser light source 60_r can be driven to continue light emission by the first light source driving circuit 20 and the second light source driving circuit 30.

Step S13, the display control circuit outputs an enable signal of an invalid level to the first light source driving circuit and the second light source driving circuit, and outputs a switch control signal of an invalid level to the first transistor corresponding to the red laser light source.

After determining that the light emission periods of the green laser light source 50_g and the red laser light source 60_r reach the fourth period, the display control circuit 10 may control the first light source driving circuit 20 to stop driving the green laser light source 50_g to emit light, and control the second light source driving circuit 30 to stop driving the red laser light source 60_r to emit light.

In step S14, the display control circuit outputs a first driving signal to the first light source driving circuit, outputs a third driving signal to the second light source driving circuit, and outputs a switching control signal of an active level to the first transistor M1 corresponding to the blue laser light source 60_b.

At this time, the green laser light source 50_g and the blue laser light source 60_b can emit light simultaneously. The light beams emitted by the two laser light sources are mixed light beams. For example, the color of the mixed beam may be cyan.

Step S15, the display control circuit detects whether the light emitting duration of the green laser light source and the blue laser light source reaches a fifth duration.

Wherein the fifth time period may be determined based on the duty time of the light beam obtained by mixing the green laser light source 50_g and the blue laser light source 60_b. The display control circuit 10 may perform step 216 described below if it detects that the light emission periods of the green laser light source 50_g and the blue laser light source 60_b reach the fifth period. If the display control circuit 10 detects that the light emission periods of the green laser light source 50_g and the blue laser light source 60_b do not reach the fifth period, the green laser light source 50_g and the blue laser light source 60_b can be driven to continue to emit light by the first light source driving circuit 20 and the second light source driving circuit 30.

In step S16, the display control circuit outputs an enable signal of an inactive level to the first light source driving circuit and the second light source driving circuit, and outputs a switch control signal of an inactive level to the first transistor corresponding to the blue laser light source.

After determining that the light emission periods of the green laser light source 50_g and the blue laser light source 60_b reach the fifth period, the display control circuit 10 may control the first light source driving circuit 20 to stop driving the green laser light source 50_g to emit light, and control the second light source driving circuit 30 to stop driving the blue laser light source 60_b to emit light.

Step S17, the display control circuit detects whether a shutdown signal is received.

The display control circuit 10 may detect whether a shutdown signal is received when a period of time during which it outputs an enable signal of an inactive level to the first light source driving circuit 20 and the second light source driving circuit 30 reaches a second target period of time (i.e., after determining that the first light source driving circuit 20 and the second light source driving circuit 30 completely stop operating). If the display control circuit 10 does not detect the shutdown signal, the above-described step S2 may be performed. When the display control circuit 10 detects the shutdown signal, the light source driving process of the laser projection apparatus may be ended.

In summary, the embodiments of the present application provide a light source driving method of a laser projection device, which is applied to the laser projection device. The display control circuit in the laser projection apparatus is capable of outputting a switching control signal to the switching circuit based on the light emission timings of the plurality of second laser light sources, and is configured to output a first drive signal to the first light source drive circuit and a second drive signal to the second light source drive circuit. The first driving signal is used for driving the first light source driving circuit to output a first driving current to the first laser light source, and the second driving signal is used for driving the second light source driving circuit to output a second driving current. The switch circuit can conduct the second light source driving circuit with one second laser light source in the plurality of second laser light sources under the control of the switch control signal so as to drive the second laser light source to emit light. Since the second light source driving circuit can drive the plurality of second laser light sources to emit light, the structure of the laser projection apparatus is effectively simplified.

The embodiment of the application provides a laser projection device, which comprises: the light source driving method provided by the above method embodiment (for example, the method shown in fig. 7, 8 or 9) is implemented when the processor executes the computer program.

Embodiments of the present application provide a computer-readable storage medium having instructions stored therein that are loaded and executed by a processor to implement a method for driving a light source (e.g., the method shown in fig. 7, 8, or 9) as provided in the method embodiments described above.

The present embodiments provide a computer program product comprising instructions which, when run on a computer, cause the computer to perform a method of driving a light source (e.g. the method shown in fig. 7, 8 or 9) as provided by the method embodiments described above.

It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program for instructing relevant hardware, where the program may be stored in a computer readable storage medium, and the above storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.

It is understood that the term "plurality" in this application means two or more. The terms "first," "second," and the like in this application are used to distinguish between identical or similar items that have substantially the same function and function, and it should be understood that there is no logical or chronological dependency between the "first," "second," and "nth" terms, nor is it limited to the number or order of execution.

The foregoing description of the exemplary embodiments of the present application is not intended to limit the invention to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, alternatives, and alternatives falling within the spirit and scope of the invention.

Claims

1. A laser projection device, the laser projection device comprising: a display control circuit, a first light source driving circuit, a second light source driving circuit, a switching circuit, a first laser light source, and a plurality of second laser light sources;

the display control circuit is respectively connected with the control end of the switch circuit, the input end of the first light source driving electricity and the input end of the second light source driving circuit, and is used for outputting switch control signals to the switch circuit and outputting first driving signals to the first light source driving circuit and outputting second driving signals to the second light source driving circuit based on the light emitting time sequence of the second laser light sources, wherein the first driving signals and the second driving signals comprise enabling signals and brightness control signals;

2. The laser projection device of claim 1, wherein the switching circuit comprises: a plurality of first transistors in one-to-one correspondence with the plurality of second laser light sources;

the grid electrode of each first transistor is used as the control end of the switch circuit to be connected with the display control circuit, the first pole of each first transistor is used as the first end of the switch circuit to be connected with the output end of the second light source driving circuit, and the second pole of each first transistor is used as the second end of the switch circuit to be connected with a corresponding second laser light source.

3. The laser projection device of claim 1, wherein the laser projection device further comprises: a first current adjusting circuit corresponding to the first light source driving circuit, and a second current adjusting circuit corresponding to the second light source driving circuit;

the first current adjusting circuit is respectively connected with the output end of the first light source driving circuit and the first laser light source, and is used for adjusting first driving current output by the first light source driving circuit;

the second current adjusting circuit is respectively connected with the output end of the second light source driving circuit, the first end of the switch circuit and the plurality of second laser light sources, and the second current adjusting circuit is used for adjusting second driving current output by the second light source driving circuit.

4. A laser projection device as claimed in claim 3, wherein the first current regulating circuit comprises: a first inductor, a first diode and a second transistor;

one end of the first inductor is connected with the output end of the first light source driving circuit and the first end of the first diode respectively, and the other end of the first inductor is connected with one end of the first laser light source;

The second end of the first diode is respectively connected with the other end of the first laser light source and the first pole of the second transistor;

the grid electrode of the second transistor is connected with the output end of the first light source driving circuit, and the second electrode of the second transistor is connected with the grounding end.

5. A laser projection device as claimed in claim 3, wherein the second current regulating circuit comprises: a second inductor, a second diode and a third transistor;

one end of the second inductor is connected with the output end of the second light source driving circuit and the first end of the second diode respectively, and the other end of the second inductor is connected with the first end of the switching circuit;

the second ends of the second diodes are respectively connected with the plurality of second laser light sources and the first poles of the third transistors;

and a grid electrode of the third transistor is connected with the output end of the second light source driving circuit, and a second electrode of the third transistor is connected with the ground end.

6. The laser projection device of any of claims 1 to 5, wherein the laser projection device further comprises: a first sampling resistor and a second sampling resistor;

One end of the first sampling resistor is connected with the output end and the feedback end of the first light source driving circuit respectively, and the other end of the first sampling resistor is connected with the grounding end;

one end of the second sampling resistor is connected with the output end and the feedback end of the second light source driving circuit respectively, and the other end of the second sampling resistor is connected with the grounding end.

7. The laser projection device as claimed in any one of claims 1 to 5, wherein the display control circuit includes: a digital light processing chip.

8. The laser projection device of any of claims 1 to 5, wherein the laser projection device further comprises: a power supply circuit;

the output end of the power supply circuit is respectively connected with the input ends of the first light source driving circuit and the second light source driving circuit, and the power supply circuit is used for providing driving voltage for the first light source driving circuit and providing driving voltage for the second light source driving circuit.

9. A light source driving method of a laser projection apparatus, characterized in that the laser projection apparatus comprises: a display control circuit, a first light source driving circuit, a second light source driving circuit, a switching circuit, a first laser light source, and a plurality of second laser light sources; the method comprises the following steps:

10. The method of claim 9, wherein the emission periods of the first laser light source and the plurality of second laser light sources do not overlap each other;

alternatively, the first laser light source overlaps with a light emission period of one of the plurality of second laser light sources, and the light emission periods of the plurality of second laser light sources do not overlap with each other.