Projection equipment and driving method of light source thereof

Abstract

The invention discloses projection equipment and a light source driving method thereof. A first blue light driving circuit (40B1) in the projection device can provide a first driving signal (DrvB1) to a first blue light source (50B1) to drive the first blue light source (50B1) to emit blue light of a first wavelength range, and a second blue light driving circuit (40B2) can provide a second driving signal (DrvB2) to a second blue light source (50B2) to drive the second blue light source (50B2) to emit blue light of a second wavelength range. Therefore, the driving modes of the blue light source in the projection equipment are effectively enriched, and the driving flexibility of the blue light source is improved. Moreover, the signal value of the first driving signal (DrvB1) is smaller than the signal value of the second driving signal (DrvB2), so that the damage of the blue light in the first wavelength range to the eyes of the user can be effectively reduced by reducing the brightness value of the blue light in the first wavelength range.

Description

Projection device and method for driving light source thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on June 30, 2022, with application number 202210769957.7, and invention name “Projection device and driving method of its light source”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of projection display technology, and in particular to a projection device and a driving method for a light source thereof. Background Art

[0004] Laser projection equipment generally includes red, green, and blue laser light sources. Each color laser light source generally includes multiple lasers connected in series, and the wavelength of the laser light emitted by these multiple lasers is within the wavelength range of that color.

[0005] In the related art, the laser projection device further includes three light source driving circuits corresponding to the three colors of laser light sources, wherein each light source driving circuit can drive the corresponding laser light source to emit light.

[0006] However, the driving method in the related art is relatively simple.

[0007] Summary of the Invention

[0008] In one aspect, the present application provides a projection device, comprising: a first blue light driving circuit, a second blue light driving circuit, a first blue light source, and a second blue light source;

[0009] The first blue light driving circuit is connected to the first blue light source, and is configured to provide a first driving signal to the first blue light source to drive the first blue light source to emit blue light in a first wavelength range;

[0010] The second blue light driving circuit is connected to the second blue light source, and the second blue light driving circuit is used to provide a second driving signal to the second blue light source to drive the second blue light source to emit blue light in a second wavelength range;

[0011] The signal value of the first driving signal is smaller than the signal value of the second driving signal, and the upper limit of the first wavelength range is smaller than or equal to the lower limit of the second wavelength range.

[0012] In another aspect, a method for driving a light source is provided, which is applied to a projection device. The projection device includes: a first blue light driving circuit, a second blue light driving circuit, a first blue light source, and a second blue light source. The method includes:

[0013] The first blue light driving circuit provides a first driving signal to the first blue light source to drive the first blue light source to emit blue light in a first wavelength range;

[0014] The second blue light driving circuit provides a second driving signal to the second blue light source to drive the second blue light source to emit blue light in a second wavelength range;

[0015] The signal value of the first driving signal is smaller than the signal value of the second driving signal, and the upper limit of the first wavelength range is smaller than or equal to the lower limit of the second wavelength range.

[0016] On the other hand, a projection device is provided, comprising: a memory, a processor, and a computer program stored in the memory, wherein the processor implements the method for driving the light source as described in the above aspects when executing the computer program.

[0017] On the other hand, a computer-readable storage medium is provided, wherein instructions are stored in the computer-readable storage medium, and the instructions are loaded and executed by a processor to implement the method for driving a light source as described in the above aspects.

[0018] In yet another aspect, a computer program product comprising instructions is provided. When the computer program product is run on a computer, the computer is enabled to execute the method for driving a light source as described in the above aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings introduced below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] FIG1 is a schematic diagram of a projection system provided in an embodiment of the present application;

[0021] FIG2 is a schematic structural diagram of a projection device provided in an embodiment of the present application;

[0022] FIG3 is a schematic diagram of the optical path principle of a projection device provided in an embodiment of the present application;

[0023] FIG4 is a schematic diagram of an optical transmission path of a projection device provided in an embodiment of the present application;

[0024] FIG5 is a schematic diagram of a circuit structure of a projection device provided in an embodiment of the present application;

[0025] FIG6 is a schematic diagram of a partial structure of a projection device provided in an embodiment of the present application;

[0026] FIG7 is a schematic diagram of a partial structure of another projection device provided in an embodiment of the present application;

[0027] FIG8 is a schematic diagram of relative brightness values ​​of light waves in a visible spectrum provided by an embodiment of the present application;

[0028] FIG9 is a schematic diagram of a partial structure of another projection device provided in an embodiment of the present application;

[0029] FIG10 is a schematic diagram of a partial structure of another projection device provided in an embodiment of the present application;

[0030] FIG11 is a schematic diagram of a partial structure of another projection device provided in an embodiment of the present application;

[0031] FIG12 is a flow chart of a method for driving a light source provided in an embodiment of the present application;

[0032] FIG13 is a flowchart of another method for driving a light source provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0034] Before explaining in detail the projection device and light source driving method provided in the embodiments of the present application, the application scenarios and implementation environments involved in the embodiments of the present application are first introduced.

[0035] Some embodiments of the present application provide a projection system 1 .

[0036] FIG1 is a structural diagram of a projection system according to some embodiments.

[0037] In some embodiments, as shown in FIG. 1 , a projection system 1 includes a projection device 100 and a projection screen 200 .

[0038] FIG2 is a structural diagram of a projection device according to some embodiments.

[0039] As shown in Figure 1, the projection device 100 includes an entire housing 1-40 (only a portion of the entire housing 40 is shown in Figure 1), and an optical engine portion assembled in the entire housing 40. In order to easily understand the functions of each part of the optical engine, the optical engine can be divided into a projection light source 1-10, an optical engine 1-20, and a projection lens 1-30. The projection light source 1-10 is configured to provide an illumination beam (laser beam). The optical engine 1-20 is configured to modulate the illumination beam provided by the projection light source 1-10 using an image signal to obtain a projection beam. The projection lens 1-30 is configured to project the projection beam onto a screen or wall for imaging. Among them, the core component of the projection light source 1-10 is the light source element, and the core component of the optical engine 1-20 is the light valve, also known as a light modulation device. With the development of miniaturization, the optical paths of the projection light source 1-10 and the optical engine 1-20 are gradually integrated into a design. In addition, the projection lens 1-30 can be a telephoto lens, such as used in some micro-projection devices, or it can be an ultra-short-focus projection lens, such as used in home or commercial high-brightness, high-quality projection devices placed near the wall.

[0040] The projection light source 1-10, optical engine 1-20, and projection lens 1-30 are sequentially connected along the direction of light beam propagation and are each enclosed by a corresponding housing. The housings of the projection light source 1-10, optical engine 1-20, and projection lens 1-30 support the corresponding optical components and ensure that each optical component meets certain sealing or airtight requirements.

[0041] FIG3 is a diagram illustrating a principle connection of an optical path of a light source, an optical engine, and a lens in a projection device according to some embodiments.

[0042] As shown in FIG3 , one end of the optical engine 1-20 is connected to the projection light source 1-10, and the projection light source 1-10 and the optical engine 1-20 are arranged along the direction of emission of the illumination beam of the projection device 100 (refer to the M direction in FIG3 ). The other end of the optical engine 1-20 is connected to the projection lens 1-30, and the optical engine 1-20 and the projection lens 1-30 are arranged along the direction of emission of the projection beam of the projection device 100 (refer to the N direction in FIG3 ). The emission direction M of the illumination beam is approximately perpendicular to the emission direction N of the projection beam. This connection structure not only adapts to the optical path characteristics of the reflective light valve in the optical engine 1-20, but also helps shorten the optical path length in one dimension, facilitating the overall layout of the device. For example, if the projection light source 1-10, the optical engine 1-20, and the projection lens 1-30 are arranged in a single dimension (e.g., the M direction), the optical path length in that dimension will be very long, which is not conducive to the overall layout of the device.

[0043] In some embodiments, the projection light sources 1-10 can sequentially provide three primary colors (or alternatively, other colors can be added to the three primary colors to create superimposed colors, such as yellow and cyan). Due to the persistence of vision phenomenon, the human eye perceives a mixture of the three primary colors as white light. Alternatively, the projection light sources 1-10 can simultaneously output the three primary colors, continuously emitting white light. Alternatively, the projection device 100 can employ a monochromatic light source in conjunction with a fluorescent wheel for time-sharing display.

[0044] In some embodiments, projection light sources 1-10 include light emitting diodes (LEDs), lasers, and the like. Lasers are widely used as light sources for projection device 100 because their emitted laser beams have good monochromaticity, high color purity, high brightness, and good directionality. In this example, projection light sources 1-10 include at least a blue laser, and may also include three other laser light sources: blue, red, and green.

[0045] When a laser projection device uses a red laser, a green laser, and a blue laser as its light source, the red laser emits a red laser beam, the green laser emits a green laser beam, and the blue laser emits a blue laser beam. Laser projection devices use these three laser beams to display images, achieving a larger color gamut and better color expression.

[0046] FIG. 4 is another light path diagram of a light source, an optical engine, and a lens in a projection device according to some embodiments.

[0047] The illumination beam emitted by the projection light source 1-10 enters the optical engine 1-20. The optical engine 1-20 includes an illumination shaping optical path and a light valve. The illumination shaping optical path is used to homogenize the illumination beam emitted by the projection light source 1-10, amplify it, and then enter the light valve at a preset angle and size after undergoing shaping processes. The illumination shaping optical path typically includes a homogenizing component, such as the light pipe 210 shown in Figure 4. It can also be a fly-eye lens or a diffraction element. It can also include lens groups and reflective elements, such as the reflector 220, lens assembly 230, and prism assembly 240 shown in Figures 3 and 4. The light pipe 210 can receive the illumination beam provided by the projection light source 1-10 and homogenize it. In addition, the outlet of the light pipe 210 can be rectangular, thereby shaping the light spot. The reflector 220 can reflect the illumination beam to the lens assembly 230. The lens assembly 230 can converge the illumination beam to the prism assembly 240. The prism assembly 240 reflects the illumination beam to the light valve 250, which modulates the illumination beam to obtain a projection beam and reflects the projection beam to the projection lens 1-30. Of course, the light pipe 210 can also be replaced by a fly-eye lens or other components with light homogenization function, and this application does not limit this.

[0048] In the optical engine 1-20, the light valve 250 uses the image signal to modulate the illumination beam provided by the projection light source 1-10, that is, to control the projection beam to display different brightness and grayscale for different pixels of the image to be displayed, ultimately forming an optical image. Depending on whether the light valve 250 transmits or reflects the illumination beam, the light modulator can be classified as a transmissive light modulator or a reflective light modulator. For example, the digital micromirror device (DMD) 250A shown in Figure 4 reflects the illumination beam and is a reflective light modulator. In contrast, the liquid crystal light valve transmits the illumination beam and is therefore a transmissive light modulator. Furthermore, depending on the number of light modulators used in the optical engine 1-20, the optical engine 1-20 can be classified as a single-chip system, a two-chip system, or a three-chip system. In some embodiments of the present application, the light valve 250 is a digital micromirror device 250A.

[0049] FIG5 is a schematic diagram of the circuit structure of a projection device provided in an embodiment of the present application. Referring to FIG5 , the projection device may include a power supply assembly 10 , a multimedia processing circuit 20 , a display control circuit 30 , a light source driving circuit 40 , a light source assembly 50 , an optical mechanical assembly 60 , and a lens 70 .

[0050] 5 , the power supply assembly 10 is connected to the multimedia processing circuit 20, the display control circuit 30, and the light source driving circuit 40. The power supply assembly 10 is used to provide operating voltages to the multimedia processing circuit 20, the display control circuit 30, and the light source driving circuit 40. The power supply assembly 10 can output a DC voltage, for example, a 12V or 24V DC voltage.

[0051] Continuing with FIG5 , the multimedia processing circuit 20 is connected to the display control circuit 30. The multimedia processing circuit 20 is configured to receive video signals via various communication interfaces, such as a universal serial bus (USB) interface, and process the video signals (e.g., brightness processing, resolution processing, color processing, etc.). The multimedia processing circuit 20 can then transmit the processed video signals to the display control circuit 30. The multimedia processing circuit 20 may include a system on chip (SoC).

[0052] The display control circuit 30 can decode and format the received video signal and further process the video signal (e.g., geometric correction processing). Afterwards, the display control circuit 30 can output the processed video signal to the optical-mechanical assembly 60. Furthermore, the display control circuit 30 can also output an enable signal and an analog dimming (ADIM) signal to the light source driving circuit 40 based on the video signal. The enable signal can be a pulse width modulation (PWM) signal.

[0053] The light source driving circuit 40 is used to receive an enable signal and an ADIM signal, and output a driving signal to the light source assembly 50 based on the enable signal and the ADIM signal to drive the light source in the light source assembly 50 to emit light. The enable signal is used to control the presence or absence of the driving signal transmitted to the light source assembly 50, and the ADIM signal is used to control the signal value of the driving signal. In an embodiment of the present application, the projection device may include multiple light source driving circuits. The multiple light source driving circuits are connected one-to-one with the multiple light sources in the light source assembly 50.

[0054] In the embodiment of the present application, the light source assembly 50 includes at least a blue light source, and may also include light sources of other colors, such as a red light source and a green light source. In one specific implementation, the light source in the light source assembly 50 may be a laser light source, and accordingly, the projection device may be a laser projection device. Alternatively, the light source in the light source assembly 50 may be another type of light source, such as a light-emitting diode (LED).

[0055] For example, referring to Figure 5, the light source driving circuit 50 in the projection device may include a red light driving circuit 40_R, a green light driving circuit 40_G, and a blue light driving circuit 40_B. The light source assembly 50 may include a red light source 50_R, a green light source 50_G, and a blue light source 50_B. Each of the three light sources is connected to a corresponding light source driving circuit. Among them, the three color light sources can emit red light, green light, and blue light respectively under the drive signal. Based on the color synthesis principle in optics, it can be seen that after the three colors of light are combined and evenly processed, white light can be obtained.

[0056] The optical-mechanical assembly 60 integrates a digital micromirror device (DMD) and a DMD driver circuit. The DMD driver circuit is used to drive the DMD based on a video signal. Under the control of the DMD driver circuit, the DMD is used to modulate the light emitted by the light source assembly 50 to produce an image to be projected. The lens 70 is capable of magnifying the image to be projected and projecting the image onto a target object in the form of a light beam. The target object can be a projection screen or a wall, for example.

[0057] Figure 6 is a schematic diagram of a partial structure of a projection device provided in an embodiment of the present application. Referring to Figure 6 , the projection device includes: a first blue light driver circuit 40_B1, a second blue light driver circuit 40_B2, a first blue light source 50_B1, and a second blue light source 50_B2. As shown in Figure 6 , the first blue light driver circuit 40_B1 is connected to the first blue light source 50_B1, and the second blue light driver circuit 40_B2 is connected to the second blue light source 50_B2.

[0058] The first blue light driving circuit 40_B1 is configured to provide a first driving signal Drv_B1 to the first blue light source 50_B1, thereby driving the first blue light source 50_B1 to emit blue light within a first wavelength range. The second blue light driving circuit 40_B2 is configured to provide a second driving signal Drv_B2 to the second blue light source 50_B2, thereby driving the second blue light source 50_B2 to emit blue light within a second wavelength range. The signal value of the first driving signal Drv_B1 is smaller than the signal value of the second driving signal Drv_B2, and the upper limit of the first wavelength range is smaller than or equal to the lower limit of the second wavelength range.

[0059] In an embodiment of the present application, each of the first blue light source 50_B1 and the second blue light source 50_B2 may include multiple light-emitting elements capable of emitting blue light. The wavelengths of blue light emitted by at least two of the multiple light-emitting elements are different. The multiple light-emitting elements included in the first blue light source 50_B1 are capable of emitting blue light within a first wavelength range when driven by a first drive signal Drv_B1, and the multiple light-emitting elements included in the second blue light source 50_B2 are capable of emitting blue light within a second wavelength range when driven by a second drive signal Drv_B2. For example, the first wavelength range may be 415 nanometers (nm) to 460 nm, and the second wavelength range may be 460 nm to 475 nm.

[0060] It's understood that within the visible spectrum, blue light typically has a wavelength between 400nm and 500nm. Because blue light has the shortest wavelength and the highest energy compared to red or green light in the visible spectrum, prolonged viewing of a display device containing a blue light source can lead to damage to eye function. Furthermore, studies have shown that blue light with wavelengths between 415nm and 460nm is most damaging to the eyes.

[0061] It is also understood that the magnitude of the drive signal transmitted to the first blue light source 50_B1 and the second blue light source 50_B2 affects the brightness (or energy) of the blue light emitted by each light-emitting element in the first blue light source 50_B1 and the second blue light source 50_B2. For example, the energy (or brightness) of the blue light emitted by each light-emitting element is positively correlated with the signal value of the drive signal received by the light-emitting element. In other words, the greater the signal value of the drive signal received by each light-emitting element, the greater the energy (or brightness) of the blue light emitted by the light-emitting element.

[0062] In this embodiment of the present application, because the signal value of the first drive signal Drv_B1 is smaller than the signal value of the second drive signal Drv_B2, the brightness (or energy) of the blue light within the first wavelength range emitted by the first blue light source 50_B1 is smaller than the brightness (or energy) of the blue light within the second wavelength range emitted by the second blue light source 50_B2. This effectively reduces the risk of harmful blue light to the user's eyes while ensuring that the overall brightness of the blue light source is not affected.

[0063] In a specific implementation, the multiple light-emitting elements included in the first blue light source 50_B1 and the second blue light source 50_B2 may be blue lasers, or the multiple light-emitting elements may be other light-emitting elements such as LEDs that can emit blue light.

[0064] In summary, the embodiments of the present application provide a projection device in which a first blue light driving circuit can provide a first driving signal to a first blue light source to drive the first blue light source to emit blue light within a first wavelength range. A second blue light driving circuit can provide a second driving signal to a second blue light source to drive the second blue light source to emit blue light within a second wavelength range. This effectively enriches the driving methods of the blue light source in the projection device and improves the driving flexibility of the blue light source.

[0065] Furthermore, because the signal value of the first drive signal is lower than the signal value of the second drive signal, the brightness of the blue light within the first wavelength range emitted by the first blue light source can be lower than the brightness of the blue light within the second wavelength range emitted by the second blue light source. Furthermore, because blue light within the first wavelength range is more harmful to the user's eyes, reducing the brightness of blue light within the first wavelength range can effectively reduce the damage to the user's eyes caused by blue light within the first wavelength range.

[0066] In one specific implementation, referring to FIG7 , the first blue light source 50_B1 may include a plurality of first blue lasers BL1 connected in series, wherein at least two of the plurality of first blue lasers BL1 emit blue light of different wavelengths. The second blue light source 50_B2 may include a plurality of second blue lasers BL2 connected in series, wherein at least two of the plurality of second blue lasers BL2 emit blue light of different wavelengths.

[0067] It's understood that the wavelength of light emitted by a laser is related to its structural characteristics. Therefore, based on requirements, multiple first blue lasers BL1 emitting blue light with wavelengths within a first wavelength range and multiple second blue lasers BL2 emitting blue light with wavelengths within a second wavelength range can be pre-determined. This allows the first blue light source 50_B1 to emit blue light within the first wavelength range, while the second blue light source 50_B2 emits blue light within the second wavelength range.

[0068] In one specific implementation, the plurality of first blue lasers BL1 and second blue lasers BL2 can all be semiconductor lasers, gas lasers, fixed lasers, etc. Furthermore, the present embodiment does not limit the number of first blue lasers BL1 included in the first blue light source 50_B1 or the number of second blue lasers BL2 included in the second blue light source 50_B2.

[0069] In one embodiment, with continued reference to FIG7 , the projection device may further include a display control circuit 30. Referring to FIG7 , the display control circuit 30 is connected to the first blue light driver circuit 40_B1 and the second blue light driver circuit 40_B2, respectively. The display control circuit 30 is configured to provide a first ADIM signal Adim_B1 and a first PWM signal Pwm_B1 to the first blue light driver circuit 40_B1, and to provide a second ADIM signal Adim_B2 and a second PWM signal Pwm_B2 to the second blue light driver circuit 40_B2. The first ADIM signal Adim_B1 and the second ADIM signal Adim_B2 are different, while the first PWM signal Pwm_B1 and the second PWM signal Pwm_B2 are the same.

[0070] In this embodiment of the present application, the display control circuit 30 may include multiple ports for outputting ADIM signals and PWM signals, with each port being connected to a light source driver circuit. Based on the received video signal, the display control circuit 30 may simultaneously output PWM signals with the same signal value and ADIM signals with different signal values ​​to the first blue light driver circuit 40_B1 and the second blue light driver circuit 40_B2.

[0071] In one embodiment, the first blue light driving circuit 40_B1 is configured to provide a first driving signal Drv_B1 to the first blue light source 50_B1 based on the first ADIM signal Adim_B1 and the first PWM signal Pwm_B1. The second blue light driving circuit 40_B2 is configured to provide a second driving signal Drv_B1 to the second blue light source 50_B2 based on the second ADIM signal Adim_B2 and the second PWM signal Pwm_B2.

[0072] In the embodiment of the present application, the first blue light driver circuit 40_B1 can adjust the signal value of the first drive signal Drv_B1 based on the first ADIM signal Adim_B1. The signal value of the first drive signal Drv_B1 can be positively correlated with the signal value of the first ADIM signal Adim_B1. That is, the larger the signal value of the first ADIM signal Adim_B1, the larger the signal value of the first drive signal Drv_B1.

[0073] Furthermore, the first blue light driver circuit 40_B1 can adjust the presence or absence of the first drive signal Drv_B1 based on the first PWM signal Pwm_B1. The frequency at which the first drive signal Drv_B1 is present or absent can be related to the duty cycle of the first PWM signal Pwm_B1. For example, if the duty cycle of the first PWM signal Pwm_B1 is 50% within one second, the first blue light driver circuit 40_B1 will output the first drive signal Drv_B1 for 0.5 seconds within that second and will not output the first drive signal Drv_B1 for the remaining 0.5 seconds.

[0074] The second blue light driving circuit 40_B2 is used to provide the second driving signal Drv_B1 to the second blue light source 50_B2 based on the second ADIM signal Adim_B2 and the second PWM signal Pwm_B2. The specific implementation process is the same as that of the first blue light driving circuit 40_B1, which will not be repeated in this embodiment of the application.

[0075] In a specific implementation, before the projection device leaves the factory, the display control circuit 30 may also be used to determine the signal values ​​of the first ADIM signal Adim_B1 and the second ADIM signal Adim_B2. The determination process may include the following steps:

[0076] Step S1: providing multiple sets of different reference ADIM signals.

[0077] Each set of reference ADIM signals may include a first reference ADIM signal provided to the first blue light driving circuit 40_B1 and a second reference ADIM signal provided to the second blue light driving circuit 40_B2 .

[0078] Step S2 : obtaining the blue brightness ratio of the first blue light source 50_B1 while the first blue light driving circuit 40_B1 and the second blue light driving circuit 40_B2 drive the first blue light source 50_B1 and the second blue light source 50_B2 to emit light based on each set of reference ADIM signals.

[0079] Step S3: Determine the first reference ADIM signal in a group of reference ADIM signals whose brightness ratio is less than the ratio threshold as the first ADIM signal Adim_B1, and determine the second reference ADIM signal in the group of reference ADIM signals as the second ADIM signal Adim_B2.

[0080] Before the projection device leaves the factory, a first reference ADIM signal and a second reference ADIM signal can be selected. The display control circuit 30 can then adjust the signal values ​​of the first and / or second reference ADIM signals to obtain multiple sets of different reference ADIM signals. It will be appreciated that since the drive signal transmitted by the light source driver circuit to the blue light source is positively correlated with the value of the ADIM signal, and the brightness or energy of the light waves emitted by the blue light source is positively correlated with the signal value of the drive signal transmitted to the blue light source, if the light source driver circuit drives the light source to emit light based on different ADIM signals, the brightness of the light waves emitted by the light source will also be different. For example, the display control circuit 30 can gradually decrease the signal value of the first reference ADIM signal and gradually increase the signal value of the second reference ADIM signal to obtain multiple sets of reference ADIM signals. In each set of reference ADIM signals, the first reference ADIM signal is obtained by adjusting the signal value of the first reference ADIM signal, and the second reference ADIM signal is obtained by adjusting the signal value of the second reference ADIM signal.

[0081] Based on the above analysis, the display control circuit 30 can sequentially transmit multiple sets of reference ADIM signals to the first and second blue light driver circuits 40_B1 and 40_B2, and output first and second PWM signals Pwm_B1 and Pwm_B2 to the first and second blue light driver circuits 40_B1 and 40_B2, respectively. The first and second blue light driver circuits 40_B1 and 40_B2 can then drive the first and second blue light sources 50_B1 and 50_B2 to emit light. During the process of the first blue light driver circuit 40_B1 driving the first blue light source 50_B1 and the second blue light driver circuit 40_B2 driving the second blue light source 50_B2 to emit light, the display control circuit 30 can obtain the brightness values ​​of the blue light emitted by the first and second blue light sources 50_B1 and 50_B2, and thereby determine the brightness contribution of the blue light emitted by the first blue light source 50_B1. The brightness ratio is the ratio of the brightness of the blue light emitted by the first blue light source 50_B1 to the total brightness of the blue light emitted by the blue light sources in the light source assembly (ie, the first blue light source 50_B1 and the second blue light source 50_B2 ).

[0082] Because the signal value of the first reference ADIM signal in the multiple sets of reference ADIM signals gradually decreases, the luminance percentage of the blue light emitted by the first blue light source 50_B1 also gradually decreases. When the display control circuit 30 determines that the luminance percentage of the blue light emitted by the first blue light source 50_B1 is less than a percentage threshold, the first reference ADIM signal in the set of reference ADIM signals corresponding to the luminance percentage may be determined as the first ADIM signal Adim_B1, and the second reference ADIM signal in the set of reference ADIM signals may be determined as the second ADIM signal Adim_B2. In one specific implementation, the percentage threshold may be 50%.

[0083] For example, if the light source assembly of the projection device includes light sources of three colors: red, green, and blue. Referring to Figure 8, the solid line in Figure 8 is the relative brightness value (or energy value) corresponding to the light waves of different wavelengths emitted by the light sources of each color in the light source assembly when the same driving signal is used to simultaneously drive the blue light sources in the first wavelength range and the second wavelength range. The dotted line in Figure 8 is the relative brightness value (or energy value) corresponding to the light waves of different wavelengths emitted by the light sources of each color in the light source assembly when different driving signals are used to respectively drive the first blue light source and the second blue light source to emit blue light using the technical solution provided by the embodiment of the present application. The horizontal axis is the wavelength of the light wave in the visible spectrum, and the vertical axis is the relative brightness value of the light wave. Among them, the relative brightness value of the light wave is the brightness value of the white light synthesized after the light wave emits light relative to the three primary colors of the light source assembly.

[0084] It can be understood that the driving scheme provided in the present application can reduce the brightness of the blue light emitted by the first blue light source in the first wavelength range (wavelength range of 415nm to 460nm), and increase the brightness of the blue light emitted by the second blue light source in the second wavelength range (wavelength range of 460nm to 475nm). Therefore, referring to Figure 8, the wavelength corresponding to the spectral peak of the visible spectrum can be moved from the initial 440nm to 460nm. Based on this, the relative brightness value of the blue light in the first wavelength range can be reduced to a certain extent, and the relative brightness value of the blue light in the second wavelength range can be increased to a certain extent, thereby effectively reducing the damage of the blue light in the first wavelength range to the user's eyes without affecting the overall brightness value of the blue light emitted by the blue light source. In addition, when the driving scheme provided in the present application is used to drive the light source assembly to emit light, it will not affect the white balance of the projected image finally projected on the target object.

[0085] In FIG8 , the brightness ratio of the blue light in the first wavelength range emitted by the first blue light source 50_B1 can be determined based on the ratio of the integral of the relative brightness value of the blue light in the first wavelength range over the wavelength to the integral of the relative brightness value of the blue light band (i.e., 400 nm to 500 nm) over the wavelength.

[0086] It is understood that in order to achieve a good display effect for the projected image projected by the projection device, the display effect of the projected image should meet the Rhine low blue light certification standard. The Rhine low blue light certification standard includes: the relative brightness of blue light in the first wavelength range in the projected image is less than a proportion threshold (for example, 50%), and the color gamut of the projected image is greater than 72% of the color gamut specified by the (US) National Television Standards Committee (NTSC). The color gamut of the projected image is the sum of the colors that the projected image can display.

[0087] When the driving method provided by this application is used to drive the light source in the light source assembly to emit light, while the brightness and white balance of the projected image ultimately projected by the projection device will not be affected (i.e., the brightness of the projected image meets the blue light brightness standards of the Rhine low blue light certification standard), the color gamut of the projected image will be affected. It is understandable that when the brightness value of the blue light in the first wavelength range is reduced, the color gamut of the projected image will also be reduced.

[0088] To ensure that the projected image ultimately projected by the projection device meets the Rhine low blue light certification standards, before the projection device leaves the factory, the display control circuit 30 may further, upon determining a set of reference ADIM signals that results in the blue light brightness ratio emitted by the first blue light source 50_B1 being less than a threshold, fine-tune the first and second reference ADIM signals within the set of reference ADIM signals, ensuring that both the brightness and color gamut of the ultimately projected image meet the Rhine low blue light certification standards. Thus, the display control circuit 30 may determine the finely adjusted first reference ADIM signal as the first ADIM signal Adim_B1 and the finely adjusted second reference ADIM signal as the second ADIM signal Adim_B2.

[0089] Figure 9 is a structural schematic diagram of a blue light driving circuit provided in an embodiment of the present application. Referring to Figure 9, each of the first blue light driving circuit 40_B1 and the second blue light driving circuit 40_B2 may include: a control circuit 410, a switching circuit 420, a power supply circuit 430 and a charging and discharging circuit 440.

[0090] The control circuit 410 is connected to the display control circuit 30 and the control terminal C of the switch circuit 420, respectively. The first terminal 1 of the switch circuit 420 is connected to the first terminal 1′ of the charge-discharge circuit 440, and the second terminal 2 of the switch circuit 420 is connected to the ground terminal GND. The control circuit 410 is configured to control the on / off states of the first terminal 1 and the second terminal 2 of the switch circuit 420 based on the ADIM signal Adim_B and the PWM signal Pwm_B transmitted by the display control circuit 30.

[0091] The second end 2' of the charge-discharge circuit 440 is connected to the power supply circuit 430 and one end of the blue light source, respectively. The third end 3' of the charge-discharge circuit 440 is connected to the other end of the blue light source. The charge-discharge circuit 440 is used to charge when the switch circuit 420 is turned on and to discharge when the switch circuit 420 is turned off.

[0092] The blue light source is configured to emit light when the charge-discharge circuit 440 is charging, and to stop emitting light when the charge-discharge circuit 440 is discharging.

[0093] The power supply circuit 430 may be the power supply assembly 10 in the projection device shown in Fig. 5. The power supply circuit 430 can provide a DC voltage to the control circuit 410, the charge and discharge circuit 440, and the blue laser in the blue light source.

[0094] In an embodiment of the present application, the control circuit 410 can output a switching signal Sw_B to the switching circuit 420 after receiving the ADIM signal Adim_B and the PWM signal Pwm_B. The switching signal Sw_B can be a level signal. When the switching signal Sw_B output by the control circuit 410 is at a high level, the first end 1 and the second end 2 of the switching circuit 420 are turned on. At this time, the DC voltage provided by the power supply circuit 430 can charge the charge and discharge circuit 440. In addition, a path can be formed between the power supply circuit 430 and the blue light source, and the DC voltage provided by the power supply circuit 430 can drive each blue laser in the blue light source to emit blue light.

[0095] When the switching signal Sw_B output by the control circuit 410 is at a low level, or when the switching signal Sw_B is not output (i.e., the switching signal Sw_B is at a zero level), the first terminal 1 and the second terminal 2 of the switch circuit 420 are turned off. At this time, the charge-discharge circuit 440 is in a discharging state, and the power supply circuit 430 cannot form a path with the blue light source. The DC voltage provided by the power supply circuit 430 cannot be transmitted to the blue light source, and the blue lasers in the blue light source stop emitting. Furthermore, during the discharge process, the charge-discharge circuit 440 can maintain the first terminal of the switch circuit 420 at a high level, so that when the next high level is transmitted to the control terminal C of the switch circuit 420, the first terminal 1 and the second terminal 2 of the switch circuit 420 can quickly turn on.

[0096] Based on the above analysis, it can be seen that the individual blue lasers in the blue light source are not in a continuous emitting state. In other words, the operating state of the multiple blue lasers periodically switches between emitting and not emitting. The display control circuit 30 can determine the brightness value of the blue light emitted at any moment within a certain time period based on the total amount of blue light emitted by the blue light source over that time period, and thus can determine the brightness contribution of the blue light emitted by the first blue light source 50_B1 at any moment.

[0097] In a specific implementation, the control circuit 410 can be an integrated chip or a circuit composed of multiple components.

[0098] As shown in FIG10 , the switching circuit 420 may include at least a switching transistor Q1. The switching transistor Q1 may be a metal oxide semiconductor (MOS) transistor. The gate of the switching transistor Q1 may serve as a control terminal C of the switching circuit 420, the first electrode of the switching transistor Q1 may serve as a first terminal 1 of the switching circuit 420, and the second electrode of the switching transistor Q1 may serve as a second terminal 2 of the switching circuit 420. The first electrode may be one of a source and a drain, and the second electrode may be the other of the source and the drain.

[0099] In a specific implementation, as shown in FIG10 , the switch circuit 420 may further include a diode D1 , a resistor R1 , a resistor R2 , a resistor R3 , and a capacitor C1 .

[0100] The charge-discharge circuit 440 may include at least one capacitor, or in addition to the at least one capacitor, may also include an inductor connected in series with the capacitor. For example, referring to FIG10 , the charge-discharge circuit 440 may include: capacitor C2, capacitor C3, diode D2, diode D3, capacitor C4, capacitor C5, and inductor L1.

[0101] In one specific implementation, referring to Figures 9 and 10 , each blue light driving circuit may further include a current detection circuit 450. The current detection circuit 450 is connected to the control circuit 410 and the second terminal 2 of the switch circuit 420, respectively. The current detection circuit 450 is configured to detect the driving current flowing through the blue light source. The control circuit 410 is further configured to control the conduction duration between the first terminal 1 and the second terminal 2 of the switch circuit 420 based on the driving current.

[0102] In the embodiment of the present application, the current detection circuit 450 can sample the driving current flowing through the blue light source to obtain a current detection signal Isen_B, and transmit the current detection signal Isen_B to the control circuit 410 .

[0103] The control circuit 410 can compare the voltage value corresponding to the received current detection signal Isen_B with a pre-stored voltage threshold. The voltage threshold can be the voltage value corresponding to the rated drive current of each blue laser in the blue light source. If the control circuit 410 determines that the voltage value corresponding to the current detection signal Isen_B is lower than the voltage threshold, it can increase the duty cycle of the switch signal Sw_B output to the switch circuit 420, that is, increase the conduction time of the first terminal 1 and the second terminal 2 of the switch circuit 420 until the voltage value corresponding to the current detection signal Isen_B is equal to the voltage threshold. In this way, the current value of the drive current flowing through each blue laser in the blue light source can be gradually increased, thereby enabling each blue laser to emit blue light normally.

[0104] If the control circuit 410 determines that the voltage corresponding to the current detection signal Isen_B is higher than the voltage threshold, it can reduce the duty cycle of the switching signal Sw_B output to the switch circuit 420. In other words, it can reduce the conduction time of the first terminal 1 and the second terminal 2 of the switch circuit 420 until the voltage corresponding to the current detection signal Isen_B is equal to the voltage threshold. This can reduce the current value of the driving current flowing through each blue laser in the blue light source, thereby allowing each blue laser to emit light normally.

[0105] Continuing with reference to Figures 9 and 10, the control circuit 410 is further configured to output an enable signal Fault_B to the power supply circuit 430. The power supply circuit 430 can output a DC voltage based on the enable signal Fault_B. When the enable signal Fault_B is at a high level, the power supply circuit 430 outputs the DC voltage. When the enable signal Fault_B is at a low level, the power supply circuit 430 stops outputting the DC voltage.

[0106] In the embodiment of the present application, if the control circuit 410 determines that the blue laser in the blue light source has an open circuit or short circuit fault based on the current detection signal Isen_B, it can control the level of the enable signal Fault_B to be low. As a result, the power supply circuit 430 stops outputting DC voltage to the charge-discharge circuit 440 and the blue light source, thereby protecting the blue lasers in the blue light source.

[0107] In one embodiment, the current detection circuit 450 may include at least one resistor, for example, multiple resistors connected in parallel, and a capacitor connected in parallel with the multiple resistors. For example, referring to FIG10 , the current detection circuit 450 may include: resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, and capacitor C6. Resistors R5 and R6 may be high-power resistors.

[0108] In one specific implementation, referring to FIG11 , the projection device may further include: a red light source 50_R, a green light source 50_G, a red light driving circuit 40_R, and a green light driving circuit 40_G. The red light driving circuit 40_R is connected to the red light source 50_R and is configured to provide a third driving signal Drv_R to the red light source 50_R to drive the red light source 50_R to emit light. The green light driving circuit 40_G is connected to the green light source 50_G and is configured to provide a fourth driving signal Drv_G to the green light source 50_G to drive the green light source 50_G to emit light.

[0109] In the embodiment of the present application, the display control circuit 30 may further provide a third ADIM signal Adim_R and a third PWM signal Pwm_R to the red light driving circuit 40_R. The red light driving circuit 40_R may then output a third drive signal Drv_R to drive the red light source 50_R to emit red light. Furthermore, the display control circuit 30 may further provide a fourth ADIM signal Adim_G and a fourth PWM signal Pwm_G to the green light driving circuit 40_G. The green light driving circuit 40_G may then output a third drive signal Drv_G to drive the green light source 50_G to emit green light.

[0110] The green light source 50_G may include multiple green lasers connected in series, and the green light emitted by these multiple green lasers is all within a third wavelength range. The red light source 50_R may include multiple red lasers connected in series, and the red light emitted by these multiple red lasers is all within a fourth wavelength range. The third wavelength range may be 500 nm to 600 nm. The fourth wavelength range may be 600 nm to 780 nm.

[0111] In one specific implementation, the circuit structures of the red light driving circuit 40_R and the green light driving circuit 40_G can be the same as the first blue light driving circuit 40_B1 (or the second blue light driving circuit 40_B2). Their specific structures and working principles can refer to the above introduction to the blue light driving circuit.

[0112] In summary, the embodiments of the present application provide a projection device in which a first blue light driving circuit can provide a first driving signal to a first blue light source to drive the first blue light source to emit blue light within a first wavelength range. A second blue light driving circuit can provide a second driving signal to a second blue light source to drive the second blue light source to emit blue light within a second wavelength range. This effectively enriches the driving methods of the blue light source in the projection device and improves the driving flexibility of the blue light source.

[0113] Furthermore, because the signal value of the first drive signal is lower than the signal value of the second drive signal, the brightness of the blue light within the first wavelength range emitted by the first blue light source can be lower than the brightness of the blue light within the second wavelength range emitted by the second blue light source. Furthermore, because blue light within the first wavelength range is more harmful to the user's eyes, reducing the brightness of blue light within the first wavelength range can effectively reduce the damage to the user's eyes caused by blue light within the first wavelength range.

[0114] FIG12 is a flow chart of a method for driving a light source provided in an embodiment of the present application. This method can be applied to a projection device, such as the projection device shown in FIG1 , FIG2 , FIG5 , FIG6 , FIG7 , FIG9 , FIG10 , or FIG11 . As shown in FIG6 , the projection device includes: a first blue light driving circuit, a second blue light driving circuit, a first blue light source, and a second blue light source. Referring to FIG12 , the method includes:

[0115] Step 801: A first blue light driving circuit provides a first driving signal to a first blue light source to drive the first blue light source to emit blue light in a first wavelength range.

[0116] In an embodiment of the present application, the first blue light source includes a plurality of light-emitting elements capable of emitting blue light, wherein at least two of the plurality of light-emitting elements emit blue light of different wavelengths. The plurality of light-emitting elements included in the first blue light source are capable of emitting blue light within a first wavelength range when driven by a first driving signal. For example, the first wavelength range may be 415 nm to 460 nm.

[0117] Step 802: The second blue light driving circuit provides a second driving signal to the second blue light source to drive the second blue light source to emit blue light in a second wavelength range.

[0118] In an embodiment of the present application, the second blue light source also includes a plurality of light-emitting elements capable of emitting blue light, and at least two of the plurality of light-emitting elements emit blue light of different wavelengths. The plurality of light-emitting elements included in the second blue light source are capable of emitting blue light within a second wavelength range when driven by a second drive signal. For example, the second wavelength range may be 460 nm to 475 nm.

[0119] The signal value of the first driving signal is smaller than the signal value of the second driving signal, and the upper limit of the first wavelength range is smaller than or equal to the lower limit of the second wavelength range.

[0120] It is understood that the magnitude of the signal value of the driving signal transmitted to the first blue light source and the second blue light source will affect the brightness value (or energy value) of the blue light emitted by each light-emitting element in the first blue light source and the second blue light source. For example, the energy value (or brightness value) of the blue light emitted by each light-emitting element is positively correlated with the signal value of the driving signal received by the light-emitting element. In other words, the greater the signal value of the driving signal received by each light-emitting element, the greater the energy value (or brightness value) of the blue light emitted by the light-emitting element.

[0121] In the embodiment of the present application, because the signal value of the first drive signal is lower than the signal value of the second drive signal, the brightness value (or energy value) of the blue light in the first wavelength range emitted by the first blue light source is lower than the brightness value (or energy value) of the blue light in the second wavelength range emitted by the second blue light source. Furthermore, because the blue light in the first wavelength range is more harmful to the user's eyes, by reducing the brightness value of the blue light in the first wavelength range, the damage to the user's eyes caused by harmful blue light can be effectively reduced without affecting the overall brightness value of the blue light source.

[0122] It is understandable that the above steps 801 and 802 are performed simultaneously, that is, the first blue light driving circuit and the second blue light driving circuit simultaneously drive the blue light sources connected thereto to emit light.

[0123] In a specific implementation, the multiple light-emitting elements included in the first blue light source and the second blue light source may be blue lasers, or the multiple light-emitting elements may be other light-emitting elements such as LEDs that can emit blue light.

[0124] In summary, the embodiments of the present application provide a method for driving a light source, which is applied to a projection device. A first blue light driving circuit in the projection device can provide a first driving signal to a first blue light source, thereby driving the first blue light source to emit blue light within a first wavelength range. A second blue light driving circuit can provide a second driving signal to a second blue light source, thereby driving the second blue light source to emit blue light within a second wavelength range. This effectively enriches the driving methods of the blue light source in the projection device and improves the driving flexibility of the blue light source.

[0125] Furthermore, because the signal value of the first drive signal is lower than the signal value of the second drive signal, the brightness of the blue light within the first wavelength range emitted by the first blue light source can be lower than the brightness of the blue light within the second wavelength range emitted by the second blue light source. Furthermore, because blue light within the first wavelength range is more harmful to the user's eyes, reducing the brightness of blue light within the first wavelength range can effectively reduce the damage to the user's eyes caused by blue light within the first wavelength range.

[0126] FIG13 is a flow chart of another method for driving a light source provided in an embodiment of the present application. This method can be applied to a projection device, such as the projection device shown in FIG1 , FIG2 , FIG5 , FIG6 , FIG7 , FIG9 , FIG10 , or FIG11 . Referring to FIG7 , the projection device may include: a display control circuit, a first blue light driving circuit, a second blue light driving circuit, a first blue light source, and a second blue light source. Referring to FIG13 , the method includes:

[0127] Step 901: The display control circuit provides multiple sets of different reference ADIM signals.

[0128] Each set of reference ADIM signals includes a first reference ADIM signal provided to the first blue light driving circuit and a second reference ADIM signal provided to the second blue light driving circuit.

[0129] Step 902 : The display control circuit obtains the brightness ratio of the blue light emitted by the first blue light source during the process in which the first blue light driving circuit and the second blue light driving circuit drive the first blue light source and the second blue light source to emit light based on each set of reference ADIM signals.

[0130] Step 903: The display control circuit determines the first reference ADIM signal in a group of reference ADIM signals whose brightness ratio is less than the ratio threshold among multiple groups of different reference ADIM signals as the first ADIM signal, and determines the second reference ADIM signal in a group of reference ADIM signals as the second ADIM signal.

[0131] Among them, the above steps 901 to 903 are steps performed by the display control circuit to determine the signal value of the first ADIM signal provided to the first blue light driving circuit and the signal value of the second ADIM signal provided to the second blue light driving circuit before the projection device leaves the factory.

[0132] Step 904: The display control circuit provides a first ADIM signal and a first PWM signal to the first blue light driving circuit.

[0133] Step 905 : The first blue light driving circuit provides a first driving signal to the first blue light source based on the first ADIM signal and the first PWM signal.

[0134] Step 906: The display control circuit provides a second ADIM signal and a second PWM signal to the second blue light driving circuit.

[0135] Step 907 : The second blue light driving circuit provides a second driving signal to the second blue light source based on the second ADIM signal and the second PWM signal.

[0136] The first ADIM signal is different from the second ADIM signal, and the first PWM signal is the same as the second PWM signal.

[0137] Referring to Figures 9 and 10 , each of the first and second blue light driver circuits includes a control circuit, a switch circuit, a power supply circuit, a charge-discharge circuit, and a current detection circuit. The control circuit is connected to the display control circuit and the control terminal of the switch circuit, respectively. The first terminal of the switch circuit is connected to the first terminal of the charge-discharge circuit, and the second terminal of the switch circuit is connected to the ground terminal. The second terminal of the charge-discharge circuit is connected to the power supply circuit and one terminal of the blue light source, respectively. The third terminal of the charge-discharge circuit is connected to the other terminal of the blue light source. The current detection circuit is connected to the control circuit.

[0138] The following describes a method for each of the first blue light driving circuit and the second blue light driving circuit to drive a blue light source. The method may include the following steps.

[0139] Step P1: The control circuit controls the on / off state of the first terminal and the second terminal of the switch circuit according to the ADIM signal and the PWM signal transmitted by the display control circuit.

[0140] Step P2: The charge-discharge circuit charges when the switch circuit is turned on, and discharges when the switch circuit is turned off.

[0141] Step P3: The blue light source emits light when the charge-discharge circuit is charging, and stops emitting light when the charge-discharge circuit is discharging.

[0142] Step P4: The current detection circuit detects the driving current flowing through the blue light source.

[0143] Step P4: The control circuit controls the conduction time between the first terminal and the second terminal of the switch circuit according to the driving current.

[0144] Referring to FIG11 , the projection device may further include: a red light source, a green light source, a red light driving circuit, and a green light driving circuit. The red light driving circuit is connected to the red light source, and the green light driving circuit is connected to the green light source. The red light driving circuit may provide a third driving signal to the red light source to drive the red light source to emit light. The green light driving circuit may provide a fourth driving signal to the green light source to drive the green light source to emit light.

[0145] It can be understood that the implementation process of each step in the above method embodiment can refer to the relevant description of each structure in the projection device in the above device embodiment, and the embodiment of the present application will not be repeated here.

[0146] It is also understood that the order of the steps of the light source driving method provided in the embodiments of the present application can be adjusted appropriately, and the number of steps can be increased or decreased according to the circumstances. For example, step 904 can be performed simultaneously with step 906, and step 905 can be performed simultaneously with step 907. Any person skilled in the art who can easily conceive of variations within the scope of the present application is within the scope of protection, and therefore will not be described in detail.

[0147] In summary, the embodiments of the present application provide a method for driving a light source, which is applied to a projection device. A first blue light driving circuit in the projection device can provide a first driving signal to a first blue light source, thereby driving the first blue light source to emit blue light within a first wavelength range. A second blue light driving circuit can provide a second driving signal to a second blue light source, thereby driving the second blue light source to emit blue light within a second wavelength range. This effectively enriches the driving methods of the blue light source in the projection device and improves the driving flexibility of the blue light source.

[0148] Furthermore, because the signal value of the first drive signal is lower than the signal value of the second drive signal, the brightness of the blue light within the first wavelength range emitted by the first blue light source can be lower than the brightness of the blue light within the second wavelength range emitted by the second blue light source. Furthermore, because blue light within the first wavelength range is more harmful to the user's eyes, reducing the brightness of blue light within the first wavelength range can effectively reduce the damage to the user's eyes caused by blue light within the first wavelength range.

[0149] An embodiment of the present application provides a projection device, which includes: a memory, a processor, and a computer program stored in the memory. When the processor executes the computer program, it implements the driving method of the light source provided in the above method embodiment (for example, the method shown in Figure 12 or Figure 13).

[0150] An embodiment of the present application provides a computer-readable storage medium storing instructions, which are loaded and executed by a processor to implement a method for driving a light source as provided in the above method embodiment (for example, the method shown in FIG. 12 or FIG. 13 ).

[0151] An embodiment of the present application provides a computer program product containing instructions. When the computer program product runs on a computer, it enables the computer to execute the light source driving method provided in the above method embodiment (for example, the method shown in Figure 12 or Figure 13).

[0152] Those skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware, or may be accomplished by a program to instruct the relevant hardware, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

Claims

1. A projection device, characterized in that: The projection device comprises: a first blue light driving circuit, a second blue light driving circuit, a first blue light source and a second blue light source; The first blue light driving circuit is connected to the first blue light source, and is configured to provide a first driving signal to the first blue light source to drive the first blue light source to emit blue light in a first wavelength range; The second blue light driving circuit is connected to the second blue light source, and the second blue light driving circuit is used to provide a second driving signal to the second blue light source to drive the second blue light source to emit blue light in a second wavelength range; The signal value of the first driving signal is smaller than the signal value of the second driving signal, and the upper limit of the first wavelength range is smaller than or equal to the lower limit of the second wavelength range.

2. The projection device according to claim 1, wherein: The first blue light source includes a plurality of first blue lasers connected in series, and at least two of the plurality of first blue lasers emit blue light of different wavelengths; the second blue light source includes a plurality of second blue lasers connected in series, and at least two of the plurality of second blue lasers emit blue light of different wavelengths.

3. The projection device according to claim 1, wherein: The projection device further includes a display control circuit; The display control circuit is connected to the first blue light driving circuit and the second blue light driving circuit respectively, and is used to provide a first analog dimming ADIM signal and a first pulse width modulation PWM signal to the first blue light driving circuit, and is used to provide a second ADIM signal and a second PWM signal to the second blue light driving circuit; The first blue light driving circuit is configured to provide a first driving signal to the first blue light source based on the first ADIM signal and the first PWM signal; The second blue light driving circuit is configured to provide a second driving signal to the second blue light source based on the second ADIM signal and the second PWM signal; The first ADIM signal is different from the second ADIM signal, and the first PWM signal is the same as the second PWM signal.

4. The projection device according to claim 3, characterized in that The display control circuit is further configured to: providing a plurality of different sets of reference ADIM signals, wherein each set of reference ADIM signals includes a first reference ADIM signal provided to the first blue light driving circuit and a second reference ADIM signal provided to the second blue light driving circuit; In the process of the first blue light driving circuit and the second blue light driving circuit driving the first blue light source and the second blue light source to emit light based on each set of reference ADIM signals, obtaining a brightness ratio of the blue light emitted by the first blue light source; The first reference ADIM signal in a group of reference ADIM signals whose brightness ratio is less than the ratio threshold among the multiple groups of different reference ADIM signals is determined as the first ADIM signal, and the second reference ADIM signal in the group of reference ADIM signals is determined as the second ADIM signal.

5. The projection device according to claim 3, characterized in that Each of the first blue light driving circuit and the second blue light driving circuit includes: a control circuit, a switch circuit, a power supply circuit and a charge and discharge circuit; The control circuit is connected to the display control circuit and the control end of the switch circuit respectively, the first end of the switch circuit is connected to the first end of the charge and discharge circuit, and the second end of the switch circuit is connected to the ground end; The control circuit is used to control the on-off state of the first end and the second end of the switch circuit according to the ADIM signal and the PWM signal transmitted by the display control circuit; The second end of the charge-discharge circuit is connected to the power supply circuit and one end of the blue light source respectively, and the third end of the charge-discharge circuit is connected to the other end of the blue light source. The charge-discharge circuit is used to charge when the switch circuit is turned on and to discharge when the switch circuit is turned off; The blue light source is used to emit light when the charge-discharge circuit is charging, and is used to stop emitting light when the charge-discharge circuit is discharging.

6. The projection device according to claim 5, characterized in that Each of the blue light driving circuits further includes: a current detection circuit; The current detection circuit is connected to the control circuit, and the current detection circuit is used to detect the driving current flowing through the blue light source; The control circuit is further configured to control the conduction time between the first end and the second end of the switch circuit according to the driving current.

7. The projection device according to any one of claims 1 to 6, characterized in that: The projection device further includes: a red light source, a green light source, a red light driving circuit and a green light driving circuit; The red light driving circuit is connected to the red light source, and is used to provide a third driving signal to the red light source to drive the red light source to emit light; The green light driving circuit is connected to the green light source, and is used to provide a fourth driving signal to the green light source to drive the green light source to emit light.

8. A method for driving a light source, characterized in that: Applied to a projection device, the projection device includes: a first blue light driving circuit, a second blue light driving circuit, a first blue light source and a second blue light source; the method includes: The first blue light driving circuit provides a first driving signal to the first blue light source to drive the first blue light source to emit blue light in a first wavelength range; The second blue light driving circuit provides a second driving signal to the second blue light source to drive the second blue light source to emit blue light in a second wavelength range; The signal value of the first driving signal is smaller than the signal value of the second driving signal, and the upper limit of the first wavelength range is smaller than or equal to the lower limit of the second wavelength range.

9. The method according to claim 8, characterized in that The projection device further includes a display control circuit; the first blue light driving circuit provides a first driving signal to the first blue light source to drive the first blue light source to emit blue light in a first wavelength range, including: The display control circuit provides a first analog dimming ADIM signal and a first pulse width modulation PWM signal to the first blue light driving circuit; The first blue light driving circuit provides a first driving signal to the first blue light source based on the first ADIM signal and the first PWM signal; The second blue light driving circuit provides a second driving signal to the second blue light source to drive the second blue light source to emit blue light in a second wavelength range, comprising: The display control circuit provides a second ADIM signal and a second PWM signal to the second blue light driving circuit; The second blue light driving circuit provides a second driving signal to the second blue light source based on the second ADIM signal and the second PWM signal; The first ADIM signal is different from the second ADIM signal, and the first PWM signal is the same as the second PWM signal.

10. The method according to claim 8 or 9, characterized in that The method further comprises: The display control circuit provides a plurality of different reference ADIM signals, wherein each reference ADIM signal includes a first reference ADIM signal provided to the first blue light driving circuit and a second reference ADIM signal provided to the second blue light driving circuit; The display control circuit obtains a brightness ratio of blue light emitted by the first blue light source during a process in which the first blue light driving circuit and the second blue light driving circuit drive the first blue light source and the second blue light source to emit light based on each set of reference ADIM signals; The display control circuit determines the first reference ADIM signal in a group of reference ADIM signals among the multiple groups of different reference ADIM signals, which makes the brightness ratio less than the proportion threshold, as the first ADIM signal, and determines the second reference ADIM signal in the group of reference ADIM signals as the second ADIM signal.

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