CN116184752A

CN116184752A - Projection device and driving method of light source thereof

Info

Publication number: CN116184752A
Application number: CN202310127228.6A
Authority: CN
Inventors: 张希刚; 刘鹏鹏
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: 2023-05-30

Abstract

The application discloses a projection device and a driving method of a light source thereof, wherein the projection device comprises: the display control circuit, the light source drive circuit, a plurality of laser light sources of different colors each other, and the switching circuit. The display control circuit is capable of outputting an enable signal and a luminance control signal to the light source driving circuit to cause the light source driving circuit to output a driving current. The display control circuit can also output a switch control signal to the switch circuit based on the light emission time sequence of the plurality of laser light sources, so that the switch circuit sequentially conducts the light source driving circuit and the plurality of light sources under the control of the switch control signal. Thus, the drive current outputted from the light source drive circuit can sequentially drive the plurality of laser light sources to emit light. The projection equipment can realize the light-emitting driving of the laser light sources with different colors only by one light source driving circuit, thereby effectively simplifying the structure of the projection equipment.

Description

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

in one aspect, there is provided a projection device comprising: the display control circuit, the light source driving circuit, a plurality of laser light sources with different colors, and the switch circuit;

the display control circuit is respectively connected with the control end of the switch circuit and the input end of the light source driving circuit, and is used for outputting a switch control signal to the switch circuit and outputting an enabling signal and a brightness control signal to the light source driving circuit based on the light emitting time sequence of the plurality of laser light sources;

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

The second end of the switch circuit is respectively connected with the plurality of light sources, and the switch circuit is used for sequentially conducting the light source driving circuit and the plurality of laser light sources under the control of the switch control signal;

the plurality of laser light sources are used for sequentially emitting light under the drive of the light source driving circuit so as to enable the projection equipment to display the projection image, wherein the light emitting periods of any two laser light sources are not overlapped with each other.

In another aspect, there is provided a driving method of a light source of a projection apparatus including a display control circuit, a light source driving circuit, a plurality of laser light sources having different colors from each other, and a switching circuit; the method comprises the following steps:

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

the light source driving circuit outputs driving current under the driving of the enabling signal and the brightness control signal;

the switch circuit is controlled by the switch control signal to conduct the light source driving circuit and the laser light sources sequentially.

In yet another aspect, there is provided a 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 projection device and a driving method of a light source thereof, wherein the projection device comprises: the display control circuit, the light source drive circuit, a plurality of laser light sources of different colors each other, and the switching circuit. The display control circuit is capable of outputting an enable signal and a luminance control signal to the light source driving circuit to cause the light source driving circuit to output a driving current. The display control circuit can also output a switch control signal to the switch circuit based on the light emission time sequence of the plurality of laser light sources, so that the switch circuit sequentially conducts the light source driving circuit and the plurality of light sources under the control of the switch control signal. Thus, the drive current outputted from the light source drive circuit can sequentially drive the plurality of laser light sources to emit light. The projection equipment can realize the light-emitting driving of the laser light sources with different colors only by one light source driving circuit, thereby effectively simplifying the structure of the projection equipment.

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 projection device according to an embodiment of the present application;

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

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

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

FIG. 5 is a schematic view of a projection apparatus according to an embodiment of the present disclosure;

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

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

fig. 8 is a flowchart of a driving method of a light source of another projection apparatus 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 projection device according to an embodiment of the present application, and referring to fig. 1, the projection device includes: a display control circuit 10, a light source driving circuit 20, a plurality of laser light sources 30 having different colors, and a switching circuit 40. The plurality of laser light sources 30 may also be referred to as lasers. For example, the plurality of laser light sources 30 may include a red laser light source, a green laser light source, and a blue laser light source.

As shown in fig. 1, the display control circuit 10 is connected to a control terminal C of the switching circuit 40 and an input terminal of the light source driving circuit 20, respectively. The display control circuit 10 is configured to output a switching control signal to the switching circuit 40 and output an enable signal EN and a luminance control signal dimining to the light source driving circuit 20 based on the light emission timings of the plurality of laser light sources 30. An output terminal of the light source driving circuit 20 is connected to the first terminal 1 of the switching circuit 40, and the light source driving circuit 20 is configured to output a driving current under driving of the enable signal EN and the brightness control signal dimmming. The second end 2 of the switching circuit 40 is connected to the plurality of laser light sources 30, and the switching circuit 40 is configured to sequentially turn on the light source driving circuit 20 and the plurality of laser light sources 30 under the control of the switching control signal. The plurality of laser light sources 30 are configured to sequentially emit light under the driving of the light source driving circuit 20, so that the projection apparatus displays a projected image. Wherein the emission periods of any two laser light sources 30 do not overlap each other.

In this embodiment of the present application, after the projection device is powered on, the display control circuit 10 of the 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 30 to control the on-off state of the switch circuit 40 (i.e. the on-off state of the first end 1 and the plurality of laser light sources 30). The display control circuit 10 is also capable of outputting an enable signal EN and a luminance control signal dimining to the light source driving circuit 20. The switch control signal may be a level signal. The enable signal EN is used to control the operation state of the light source driving circuit 20, i.e., to control whether the light source driving circuit 20 outputs a driving current. The brightness control signal dimping is used to control the magnitude of the driving current output from the light source driving circuit 20.

The light emission information of the plurality of laser light sources 30 may include duty time and current information of the plurality of laser light sources 30. The duty time of the plurality of laser light sources 30 may indicate the light emission timing and the light emission duration of the plurality of laser light sources 30 within a unit time duration (e.g., 1 second). The current information of the plurality of laser light sources 30 refers to a rated driving current required when the plurality of laser light sources 30 emit light. The rated drive current of the laser light source 30 is a drive current capable of driving the laser light source 30 to normally emit light.

The display control circuit 10 may include a digital light processing (digital light processing, DLP) chip, among others. 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 light source driving circuit 20 may include a constant current driving integrated circuit (integrated circuit, IC), which may also be referred to as a constant current driving chip.

The light source driving circuit 20 can output a driving current after receiving the enable signal EN and the brightness control signal dimining. Wherein the brightness control signal dimping 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 brightness control signal dimping, i.e., the larger the duty cycle of the brightness control signal dimping, the higher the signal value of the driving current. Accordingly, the higher the light emission luminance of the laser light source 30 driven by the driving current.

The switching circuit 40 can sequentially turn on the light source driving circuit 20 and the plurality of laser light sources 30 under the control of the switching control signal after receiving the switching control signal. Thus, the driving current outputted from the light source driving circuit 20 can drive the plurality of laser light sources 30 to sequentially emit light, so that the projected apparatus displays a projected image. That is, the display control circuit 10 can display a projected image by sequentially driving the plurality of laser light sources 30 to emit light by the light source driving circuit 20. Also, the light source driving circuit 20 may drive only one laser light source 30 of the plurality of laser light sources 30 to emit light in the same period, that is, the emission periods of the plurality of laser light sources 30 are not overlapped. Therefore, the laser light sources 30 with two different colors at the same time can be prevented from emitting light simultaneously, the problem of color mixing of the laser light sources 30 in the light emitting process is avoided, and the display effect of the projection image is effectively ensured.

It can be understood that, because the switching circuit 40 can control the on-off state of the light source driving circuit 20 and any one of the plurality of laser light sources 30 under the control of the switching control signal, the projection device can realize the light emission driving of the plurality of laser light sources 30 with different colors only by one light source driving circuit 20. Therefore, the structure of the projection device is effectively simplified, and the manufacturing cost of the projection device is reduced.

In summary, embodiments of the present application provide a projection apparatus, including: the display control circuit, the light source drive circuit, a plurality of laser light sources of different colors each other, and the switching circuit. The display control circuit is capable of outputting an enable signal and a luminance control signal to the light source driving circuit to cause the light source driving circuit to output a driving current. The display control circuit can also output a switch control signal to the switch circuit based on the light emission time sequence of the plurality of laser light sources, so that the switch circuit sequentially conducts the light source driving circuit and the plurality of light sources under the control of the switch control signal. Thus, the drive current outputted from the light source drive circuit can sequentially drive the plurality of laser light sources to emit light. The projection equipment can realize the light-emitting driving of the laser light sources with different colors only by one light source driving circuit, thereby effectively simplifying the structure of the projection equipment.

Fig. 2 is a schematic structural diagram of another projection device according to an embodiment of the present application, and referring to fig. 2, the projection device may further include: a power supply circuit 50. An output terminal of the power supply circuit 50 is connected to an input terminal of the light source driving circuit 20, and the power supply circuit 50 is configured to supply a driving voltage VCC to the light source driving circuit 20. Thereby, the light source driving circuit 20 can be enabled to output a driving current by the driving voltage VCC.

Alternatively, the power circuit 50 may include an alternating current-direct current (AC-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 laser light sources 30.

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 light source driving circuit 20 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 laser light sources 30 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).

Alternatively, the display control circuit 10 may be configured to output the switching control signals to the gates G of the plurality of first transistors M1 in one-to-one correspondence. Each first transistor M1 is configured to control the on-off state of the light source driving circuit 20 and a corresponding one of the laser light sources 30 under the control of the received switch control signal. The switch control signal may be a level signal. When the first transistor M1 receives the switching control signal of the active level, the first transistor M1 can turn on one laser light source 30 corresponding to the first transistor M1 of the light source driving circuit 20. When the first transistor M1 receives the switching control signal of the inactive level, the first transistor M1 can turn off one of the laser light sources 30 of the light source driving circuit 20 corresponding to the first transistor M1.

When the display control circuit 10 outputs the switching control signals to the gates G of the first transistors M1 in one-to-one correspondence, the light source driving circuit 20 may sequentially output the luminance control signals dimmming corresponding to the laser light sources 30 in one-to-one correspondence. In the output period of the brightness control signal dimmming corresponding to each laser light source 30, the level of the switching control signal received by the first transistor M1 corresponding to the laser light source 30 is an active level.

In this embodiment, 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 30 can be obtained during the projection process of the projection device. The light emission information may include duty time and current information of the plurality of laser light sources 30, among others. The duty time of the plurality of laser light sources 30 may indicate the light emission timing and the light emission duration of the plurality of laser light sources 30. The light emission information of the plurality of laser light sources 30 may be stored in advance in the display control circuit 10. Alternatively, the projection device may further comprise a memory. The light emission information of the plurality of laser light sources 30 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 laser light source 30, an inactive level to the gate G of the first transistor M1 corresponding to the other laser light sources 30 other than the target laser light source 30 among the plurality of laser light sources 30, and a luminance control signal dimmming corresponding to the target laser light source 30 to the light source driving circuit 20 based on the light emission information of the plurality of laser light sources 30. The active level of the switch control signal may be low with respect to the inactive level. The target laser light source 30 may be the laser light source 30 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 30.

In the embodiment of the present application, the light source driving circuit 20 can transmit the driving current to the sources S of the plurality of first transistors M1 based on the brightness control signal diming corresponding to the target laser light source 30. After receiving the enable signal of the active level, the gate G of the first transistor M1 corresponding to the target laser light source 30 can turn on the source S and the drain D thereof. Thereby, the driving current outputted from the light source driving circuit 20 can drive the target laser light source 30 to emit light.

When the target laser light source 30 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 laser light source 30, so that the first transistor M1 turns off the source S and the drain D thereof. Thereby, the driving current output from the light source driving circuit 20 can be stopped from driving the target laser light source 30 to emit light.

The on-time of the first transistor M1 corresponding to the target laser light source 30 may be the duty time of the target laser light source 30. After determining that the on-time of the first transistor M1 corresponding to the target laser light source 30 reaches the duty time of the target laser light source 30, 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 G of the first transistor M1 corresponding to another laser light source 30 (i.e., a new target laser light source 30) among the plurality of laser light sources 30, and output the luminance control signal dimimgn corresponding to the other laser light source 30 to the light source driving circuit 20.

Based on the above analysis, during a period in which the display control circuit 10 outputs the corresponding luminance control signal dimmming of the target laser light source 30 to the light source driving circuit 20, the level of the switching control signal received by the first transistor M1 corresponding to the target laser light source 30 is an active level, and the first transistor M1 is in an on state. In a period in which the display control circuit 10 stops outputting the corresponding luminance control signal dimmming of the target laser light source 30 to the light source driving circuit 20, the level of the switching control signal received by the first transistor M1 corresponding to the target laser light source 30 is an inactive level, and the first transistor M1 is in an off state.

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 laser light source 30 of the plurality of laser light sources 30 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 laser light source 30 reaches the target duration. Therefore, the simultaneous light emission of the two laser light sources 30 with different colors at the same time can be avoided, the problem of color mixing of the laser light sources 30 in the light emission process is avoided, and the light emission purity of the plurality of laser light sources 30 is effectively ensured. The target duration may be determined based on the off duration of the first transistor M1 corresponding to the target laser light source 30, 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 laser light sources 30 may be the same, and accordingly, the interval between the light emission periods of the adjacent two laser light sources 30 may be a fixed target period.

For example, referring to fig. 3, the plurality of laser light sources 30 may include a red laser light source 30_r, a green laser light source 30_g, and a blue laser light source 30_b. As shown in fig. 3 and 4, after the display control circuit 10 is powered on, the enable signal EN of an active level may be output to the light source driving circuit 20, and the switch control signal drvm_1 of an active level may be output to the gate G of the first transistor M1 corresponding to the red laser light source 30_r, the luminance control signal dimimgn corresponding to the red laser light source 30_r may be output to the light source driving circuit 20, the switch control signal drvm_2 of an inactive level may be output to the gate G of the first transistor M1 corresponding to the green laser light source 30_g, and the switch control signal drvm_3 of an inactive level may be output to the gate G of the first transistor M1 corresponding to the blue laser light source 30_b.

At this time, the driving current i_r output from the light source driving circuit 20 can flow through the red laser light source 30_r to drive the red laser light source 30_r to emit light. The current flowing through the green laser light source 30_g and the blue laser light source 30_b is 0, and the green laser light source 30_g and the blue laser light source 30_b do not emit light.

After the light emission duration of the red laser light source 30_r reaches the duty time duty1 corresponding to the red laser light source 30_r, the display control circuit 10 may output the switching control signal drvm_1 of an inactive level to the first transistor M1 corresponding to the red laser light source 30_r to control the first transistor M1 corresponding to the red laser light source 30_r to be in an off state, and output the switching control signal drvm_2 of an active level to the gate G of the first transistor M1 corresponding to the green laser light source 30_g, and output the brightness control signal dimimgn corresponding to the green laser light source 30_g to the light source driving circuit 20.

At this time, the driving current i_g outputted from the light source driving circuit 20 can flow through the green laser light source 30_g to drive the green laser light source 30_g to emit light. The current flowing through the red laser light source 30_r and the blue laser light source 30_b is 0, and the red laser light source 30_r and the blue laser light source 30_b do not emit light.

After the light emission duration of the green laser light source 30_g reaches the duty time duty2 corresponding to the green laser light source 30_g, the display control circuit 10 may output the switching control signal drvm_2 of an inactive level to the first transistor M1 corresponding to the green laser light source 30_g to control the first transistor M1 corresponding to the green laser light source 30_g to be in an off state, and output the switching control signal drvm_3 of an active level to the gate G of the first transistor M1 corresponding to the blue laser light source 30_b, and output the brightness control signal dimimgn corresponding to the blue laser light source 30_b to the light source driving circuit 20.

At this time, the driving current i_b output from the light source driving circuit 20 can flow through the blue laser light source 30_b to drive the blue laser light source 30_b to emit light. The current flowing through the red laser light source 30_r and the green laser light source 30_g is 0, and the red laser light source 30_r and the green laser light source 30_g do not emit light.

Optionally, as shown in fig. 5, the projection device may further include: a current regulating circuit 60. The current adjusting circuit 60 is connected to the output terminal of the light source driving circuit 20, the first terminal 1 of the switching circuit 40, and the plurality of laser light sources 30, respectively. The current adjusting circuit 60 is used for adjusting the driving current outputted from the light source driving circuit 20.

It will be appreciated that the driving current output by the light source driving circuit 20 may be different from the driving current flowing through the laser light source 30, i.e. the driving current received by the laser light source 30 is not consistent with the rated driving current required when the laser light source 30 emits light. Accordingly, the current adjusting circuit 60 in the projection apparatus may adjust the magnitude of the driving current outputted from the light source driving circuit 20 so that the driving current actually flowing through the laser light source 30 is consistent with the rated driving current required by the laser light source 30. This ensures that the laser light source 30 can emit light normally, and that the display effect of the projected image projected by the projection device is good.

Alternatively, as shown in fig. 5, the current adjusting circuit 60 may include: a tank inductance L1, a diode D1 and a second transistor M2.

Referring to fig. 5, one end of the energy storage inductor L1 is connected to the output end of the light source driving circuit 20 and the first end of the diode D1, respectively, and the other end of the energy storage inductor L1 is connected to the first end 1 of the switching circuit 40. The second terminal of the diode D1 is connected to the plurality of laser light sources 30 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 light source driving circuit 20, and the second pole of the second transistor M2 is connected to the ground terminal GND.

Alternatively, referring to fig. 5, the first end of the diode D1 may be a cathode and the second end of the diode D1 may be an anode. The second transistor M2 may be a P-type MOS transistor. The first pole of the second transistor M2 may be a source S, and the second pole of the second transistor M2 may be a drain D.

In the embodiment of the present application, the light source driving circuit 20 may output the driving signal DRV to the gate G of the second transistor M2 while outputting the driving current to the first transistor M1 corresponding to the target laser light source 30. The driving signal DRV 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 signal DRV output from the light source driving circuit 20 is output 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 diode D1 is in an off state. Thereby, the light source driving circuit 20 can be made conductive to the ground GND so that the laser light source 30 is in a light emitting state.

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

When the driving signal DRV output from the light source driving circuit 20 is in the form of pulses 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 diode D1 is in a conductive state, and the energy storage inductor L1 is in a discharge state. Therefore, when the second transistor M2 is in the off state, the electric energy discharged from the energy storage inductor L1 can continue to drive the laser light source 30 to emit light. Thereby, the stability of the light emission of the laser light source 30 can be ensured.

It is understood that the light source driving circuit 20 may change the on-time of the second transistor M2 by adjusting the duty ratio of the driving signal DRV outputted therefrom. When the duty ratio of the driving signal DRV in a unit time (for example, 1 second) is relatively small, the on-time of the second transistor M2 in the unit time is long, and the driving current flowing through the laser light source 30 is also large. When the duty ratio of the driving signal DRV 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 driving current flowing through the laser light source 30 is relatively small. Thus, the adjustment of the driving current flowing through the laser light source 30 can be realized, so that the difference between the driving current flowing through the laser light source 30 and the rated driving current of the laser light source 30 is small, and the light emitting effect of the laser light source 30 is ensured.

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

In the embodiment of the present application, when the output terminal (i.e., the end outputting the driving current) of the light source driving circuit 20 is connected to the ground terminal GND, the sampling resistor R1 is capable of sampling the driving current flowing through the laser light source 30. The light source driving circuit 20 can receive the driving current sampled by the sampling resistor R1 through its feedback terminal. The light source driving circuit 20 may store the rated driving current of the laser light source 30 in advance. The light source driving circuit 20 can adjust the duty ratio of the driving signal DRV outputted therefrom based on the sampled driving current and the rated driving current stored in advance.

For example, when the light source driving circuit 20 determines that the sampled driving current is smaller than the rated driving current, the duty ratio of the driving signal DRV 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 driving current flowing through the laser light source 30 may be increased. When the light source driving circuit 20 determines that the sampled driving current is greater than the rated driving current, the duty ratio of the driving signal DRV outputted therefrom may be increased, so that the on-time of the second transistor M2 may be reduced, thereby reducing the current value of the driving current flowing through the laser light source 30.

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 plurality of light source driving circuits 03 corresponding to the plurality of light sources, and a plurality of current adjusting circuits 04 corresponding to the plurality of light sources. Wherein. Each current regulation circuit 04 includes: a tank inductor L2, a diode D2, and a third transistor M3. Alternatively, as shown in fig. 6, 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 R2 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 R2.

When the display control circuit 01 outputs the luminance control signal dimmming and the enable signal EN of an 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 a driving current to the red light source 02_r through the energy storage inductor L2 and output a driving signal DRV to the gate G of the third transistor M3. The third transistor M3 can be switched in an on-off state under the control of the driving signal DRV, 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 plurality of light sources emit light, the plurality of third transistors M3 in the current adjusting circuit 04 corresponding to the plurality of light sources are in a high-speed switching state. When the plurality of third transistors M3 frequently switch the switching states, 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 third transistors M3 generate a large amount of heat during the switching process and the turn-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. 6, a projection apparatus in the related art needs to be provided with a plurality of light source driving circuits 03 and energy storage inductors L2. The plurality of light source driving circuits 03 and the energy storage inductor L2 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 addition, in the projection apparatus according to the related art, when light emission driving of a plurality of light sources is realized, the display control circuit 01 needs to output the luminance adjustment signal dimmming and the enable signal EN to the plurality of light source driving circuits 03 corresponding to the plurality of light sources one by one. For example, if the projection apparatus includes 3 light sources, the display control circuit 01 needs to output the 3-way enable signal EN and the 3-way brightness adjustment signal diming at the same time. This increases the complexity of the output signal of the display control circuit 01.

In the projection apparatus provided in the present application, only one light source driving circuit 20 and one switching circuit 40 are required to realize the light emission driving of the plurality of laser light sources 30. Thus, the display control circuit 10 only needs to output one enable signal EN and one luminance adjustment signal dimingto the light source driving circuit 20 at the same time, and output a switching control signal to the switching circuit 40. Therefore, the complexity of the output signal of the display control circuit is effectively reduced. In addition, only one current adjusting circuit 60 is needed to be arranged in the projection device, so that the adjustment of the driving current output by the light source driving circuit 20 can be realized. Therefore, the structure of the light source driving plate in the projection device is effectively simplified, and the cost of the projection device is reduced. In addition, because the structure of the light source driving plate of the projection device is simpler and the area is smaller, 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 projection device is further realized.

It is also understood that in the projection apparatus provided in the present application, only the second transistor M2 is in the high-speed switching state. Thus, the heat and electromagnetic radiation generated by the current adjusting circuit 60 in the process of adjusting the driving current output from the light source driving circuit 20 can be effectively reduced. Therefore, the projection device does not need to be provided with a radiator and a device for shielding electromagnetic radiation, so that the structure of the projection device is further simplified, and the cost of the projection device is further reduced.

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

Step 101, a display control circuit outputs a switch control signal to a switch circuit and outputs an enable signal and a brightness control signal to a light source driving circuit based on the light emission timings of the plurality of laser light sources.

Alternatively, the light emission information of the plurality of laser light sources 30 may include duty time and current information of the plurality of laser light sources 30. The duty time of the plurality of laser light sources 30 may indicate the light emission timing and the light emission duration of the plurality of laser light sources 30. The current information of the plurality of laser light sources 30 refers to a rated driving current required when the plurality of laser light sources 30 emit light. The rated drive current of the laser light source 30 is a drive current capable of driving the laser light source 30 to normally emit light.

Step 102, the light source driving circuit outputs driving current under the driving of the enabling signal and the brightness control signal.

Wherein the brightness control signal dimmming may be a PWM signal. The magnitude of the driving current outputted from the light source driving circuit 20 is positively correlated with the duty ratio of the brightness control signal dimmming, that is, the larger the duty ratio of the brightness control signal dimmming is, the higher the signal value of the driving current outputted from the light source driving circuit 20 is. Accordingly, the higher the light emission luminance of the laser light source 30 driven by the driving current.

Step 103, the switching circuit sequentially turns on the light source driving circuit and the plurality of laser light sources under the control of the switching control signal so as to drive the plurality of laser light sources to sequentially emit light, and then the projection equipment displays the projection image.

In the embodiment of the present application, the display control circuit 10 drives the plurality of laser light sources 30 to sequentially emit light through the light source driving circuit 20, so as to realize the display of the projection image.

Alternatively, the on periods of the adjacent two laser light sources 30 and the light source driving circuit 20 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 light source driving circuit 20 may drive only one laser light source 30 of the plurality of laser light sources 30 to emit light in the same period, that is, the emission periods of the plurality of laser light sources 30 are not overlapped. The duration of the light emission periods of the plurality of laser light sources 30 may be the same or different.

It will be appreciated that the switching circuit 40 requires a certain period of time when switching the path between the light source driving circuit 20 and the plurality of laser light sources 30. By enabling the conduction time intervals of the two adjacent laser light sources 30 and the light source driving circuit 20 to be longer than the target time interval, the light source driving circuit 20 can be prevented from driving the two laser light sources 30 with different colors to emit light at the same time, the problem of color mixing of the laser light sources 30 in the light emitting process is further avoided, and the light emitting purity of the plurality of laser light sources 30 is effectively ensured. Thus, the display effect of the projection image projected by the projection device can be effectively ensured.

It can be further understood that, because the switching circuit 40 can control the on-off states of the light source driving circuit 20 and any one of the plurality of laser light sources 30 under the control of the switching control signal, the projection device can realize the light emission driving of the plurality of laser light sources 30 with different colors only by one light source driving circuit 20. Therefore, the structural complexity of the projection device is effectively reduced, and the manufacturing cost of the projection device is reduced.

Referring to fig. 3, the plurality of laser light sources 30 may include a red laser light source 30_r, a green laser light source 30_g, and a blue laser light source 30_b, and the switching circuit 40 may include three first transistors M1 connected to the three laser light sources in a one-to-one correspondence. A driving method of the three laser light sources 30 will be described below. Referring to fig. 8, the driving method may include:

And S1, powering on and starting up the projection equipment.

The user can control the projection device to be powered on and started in a remote control mode or a mode of pressing a switch key of the projection device.

And S2, initializing a display control circuit.

After the 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 30 in the projection apparatus during the initialization process.

And S3, the display control circuit outputs a switch control signal of an effective level to the first transistor corresponding to the red laser light source.

The first transistor M1 can turn on the light source driving circuit 20 and the red laser light source 30_r under the control of the switching control signal of the active level. At this time, the display control circuit 10 outputs the level of the switching control signal to the first transistor M1 corresponding to the green laser light source 30_g and the blue laser light source 30_b as the inactive level.

And S4, the display control circuit outputs an enabling signal and a brightness control signal corresponding to the red laser light source to the light source driving circuit.

The light source driving circuit 20 can output a driving current based on the luminance control signal dimmming corresponding to the red laser light source 30_r. The driving current can be transmitted to the red laser light source 30_r through the first transistor M1 corresponding to the red laser light source 30_r. At this time, the red laser light source 30_r can emit light under the drive of the drive current, and the green laser light source 30_g and the blue laser light source 30_b do not emit light.

And S5, the display control circuit detects whether the light emitting duration of the red laser source reaches a first duration.

The first duration is a duration determined by the display control circuit 10 based on the light emission information of the plurality of laser light sources 30, and may be a duty time of the red laser light source 30_r. If the display control circuit 10 determines that the light emission period of the red laser light source 30_r reaches the first period, the following step S6 may be performed. If the display control circuit 10 determines that the light emission period of the red laser light source 30_r does not reach the first period, the light source driving circuit 20 may continue to drive the red laser light source 30_r to emit light.

And S6, 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 30_r reaches the first 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 30_r. The first transistor M1 can turn off the light source driving circuit 20 and the red laser light source 30_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 30_r stops emitting light.

And S7, after the display control circuit detects that the turn-off time length of the red laser light source and the light source driving circuit reaches the target time length, outputting a switch control signal of an effective level to a first transistor corresponding to the green laser light source.

The target time period may also be referred to as a delay time period. The first transistor M1 corresponding to the green laser light source 30_g can turn on the light source driving circuit 20 and the green laser light source 30_b under the control of the switching control signal of the active level.

And S8, the display control circuit outputs a brightness control signal corresponding to the green laser light source to the light source driving circuit.

The light source driving circuit 20 can output a driving current based on the luminance control signal dimmming corresponding to the green laser light source 30_g. The driving current can be transmitted to the green laser light source 30_g through the first transistor M1 corresponding to the green laser light source 30_g. At this time, the green light source 30_g can emit light under the drive of the drive current, and the red laser light source 30_r and the blue laser light source 30_b do not emit light.

Step S9, the display control circuit detects whether the light emitting duration of the green light source reaches the second duration.

The second duration may be a duty time of the green laser light source 30_g. If the display control circuit 10 determines that the light emission period of the green laser light source 30_g reaches the second period, the following step S10 may be performed. If the display control circuit 10 determines that the light emission period of the green laser light source 30_g does not reach the second period, the light emission of the green laser light source 30_g may be continued to be driven by the light source driving circuit 20.

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

After determining that the light emission period of the green laser light source 30_g 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 green laser light source 30_g. The first transistor M1 can turn off the light source driving circuit 20 and the green laser light source 30_g under the control of the switching control signal of the inactive level. After the first transistor M1 is completely turned off, the green laser light source 30_g stops emitting light.

And S11, after the display control circuit detects that the turn-off time length of the green laser light source and the light source driving circuit reaches the target time length, outputting a switch control signal of an effective level to a first transistor corresponding to the blue laser light source.

The first transistor M1 corresponding to the blue laser light source 30_b can turn on the blue laser light source 30_b and the light source driving circuit 20 under the control of the switching control signal.

Step S12, the display control circuit outputs a brightness control signal corresponding to the blue laser light source to the light source driving circuit.

The light source driving circuit 20 can output a driving current based on the luminance control signal dimmming corresponding to the blue laser light source 30_b. The driving current can be transmitted to the blue laser light source 30_b through the first transistor M1 corresponding to the blue laser light source 30_b. At this time, the blue light source 30_b can emit light by the driving current, and the red laser light source 30_r and the green laser light source 30_g do not emit light.

Step S13, the display control circuit detects whether the light emitting duration of the blue laser light source reaches a third duration.

The third duration may be a duty time of the blue laser light source 30_b. If the display control circuit 10 determines that the light emission period of the blue laser light source 30_b reaches the third period, the following step S14 may be performed. If the display control circuit 10 determines that the light emission period of the blue laser light source 30_b does not reach the third period, the light emission of the blue laser light source 30_b may be continued to be driven by the light source driving circuit 20.

Step S14, the display control circuit outputs a switch control signal of invalid level to the first transistor corresponding to the blue laser light source.

After determining that the light emission period of the blue laser light source 30_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 30_b. The first transistor M1 can turn off the light source driving circuit 20 and the blue laser light source 30_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 30_b stops emitting light.

Step S15, the display control circuit detects whether a shutdown signal is received.

If the display control circuit 10 does not detect the shutdown signal, the above step S3 may be performed after the turn-off duration of the blue laser light source 30_b and the light source driving circuit 20 reaches the target duration. When the display control circuit 10 detects the shutdown signal, the light source driving process of the projection apparatus may be ended.

In summary, embodiments of the present application provide a light source driving method of a projection apparatus, where the projection apparatus includes: the display control circuit, the light source drive circuit, a plurality of laser light sources of different colors each other, and the switching circuit. The display control circuit is capable of outputting an enable signal and a luminance control signal to the light source driving circuit to cause the light source driving circuit to output a driving current. The display control circuit can also output a switch control signal to the switch circuit based on the light emission time sequence of the plurality of laser light sources, so that the switch circuit sequentially conducts the light source driving circuit and the plurality of light sources under the control of the switch control signal. Thus, the drive current outputted from the light source drive circuit can sequentially drive the plurality of laser light sources to emit light. The projection equipment can realize the light-emitting driving of the laser light sources with different colors only by one light source driving circuit, thereby effectively simplifying the structure of the projection equipment.

The embodiment of the application provides a projection device, which comprises: the light source driving method provided by the above method embodiment (for example, the method shown in fig. 7 or fig. 8) 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 of driving a light source (e.g., the method shown in fig. 7 or 8) as provided by 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 or 8) 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.

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 projection device, the projection device comprising: the display control circuit, the light source driving circuit, a plurality of laser light sources with different colors, and the switch circuit;

2. The projection device of claim 1, wherein the switching circuit comprises: a plurality of first transistors in one-to-one correspondence with the plurality of 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 electrode of each first transistor is used as the first end of the switch circuit to be connected with the output end of the light source driving circuit, and the second electrode of each first transistor is used as the second end of the switch circuit to be connected with a corresponding laser light source.

3. The projection apparatus according to claim 2, wherein the display control circuit is configured to output switching control signals to gates of the plurality of first transistors in one-to-one correspondence;

Each first transistor is used for controlling the on-off state of the light source driving circuit and a corresponding laser light source under the control of the received switch control signal.

4. The projection apparatus according to claim 3, wherein the display control circuit is configured to sequentially output a plurality of luminance control signals corresponding to the plurality of laser light sources one by one to the light source driving circuit;

and in the output period of the brightness control signal corresponding to each laser light source, the level of the switching control signal received by the first transistor corresponding to the laser light source is an effective level.

5. The projection device of any one of claims 1 to 4, further comprising: a current regulating circuit;

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

6. The projection device of claim 5, wherein the current regulating circuit comprises: an energy storage inductor, a diode and a second transistor;

One end of the energy storage inductor is respectively connected with the output end of the light source driving circuit and the first end of the diode, and the other end of the energy storage inductor is connected with the first end of the switch circuit;

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

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

7. The projection device of any one of claims 1 to 4, further comprising: sampling a resistor;

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

8. The projection device of any one of claims 1 to 4, further comprising: a power supply circuit;

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

9. A driving method of a light source of a projection apparatus is characterized in that the projection apparatus includes a display control circuit, a light source driving circuit, a plurality of laser light sources having different colors from each other, and a switching circuit; the method comprises the following steps:

the switching circuit is controlled by the switching control signal to sequentially conduct the light source driving circuit and the plurality of laser light sources so as to drive the plurality of laser light sources to sequentially emit light, and further the projection equipment displays projection images, wherein the light emitting periods of any two laser light sources are not overlapped with each other.

10. The method of claim 9, wherein the emission periods of adjacent two laser light sources are separated by a target length.