WO2021008226A1 - 激光投影设备 - Google Patents

激光投影设备 Download PDF

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Publication number
WO2021008226A1
WO2021008226A1 PCT/CN2020/091012 CN2020091012W WO2021008226A1 WO 2021008226 A1 WO2021008226 A1 WO 2021008226A1 CN 2020091012 W CN2020091012 W CN 2020091012W WO 2021008226 A1 WO2021008226 A1 WO 2021008226A1
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Prior art keywords
laser
circuit
sub
current
resistor
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PCT/CN2020/091012
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English (en)
French (fr)
Inventor
崔荣荣
郭大勃
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青岛海信激光显示股份有限公司
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Publication of WO2021008226A1 publication Critical patent/WO2021008226A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H04N9/3161—Modulator illumination systems using laser light sources
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2006—Lamp housings characterised by the light source
    • G03B21/2033—LED or laser light sources
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]

Definitions

  • This application belongs to the field of projection display, and particularly relates to a laser projection device.
  • Laser projection equipment such as ultra-short-focus laser TVs are widely used in the display field because of their advantages of high color purity, large color gamut, and high brightness.
  • the current laser TV includes a light source system to provide a three-color projection light source for the laser TV.
  • the light source system usually includes a laser light source, a fluorescent wheel and a color filter wheel, and the laser light source is usually a blue laser component for emitting blue laser light.
  • the blue laser is irradiated on three different areas of the fluorescent wheel sequentially to generate three-color light, and the three-color light is filtered through the color filter wheel in order to obtain three-color light with higher purity.
  • the light source system irradiates the blue laser to the fluorescent wheel to generate three-color light, the light saturation is not high, and it cannot restore the colors of nature in a larger range.
  • red lasers and green lasers have gradually matured.
  • the light source system used in laser projection is converted to a full three-color laser light source system.
  • the laser light source of the full three-color light source system includes three-color lasers to directly generate three primary colors of monochromatic light, effectively improving the color gamut of the image.
  • the types and numbers of lasers included in the full three-color light source system have increased, and the light-emitting principles and performance of different color lasers are also different.
  • the brightness of the laser and the color temperature of the composition will occur. Changes, resulting in poor image display effect of laser projection equipment.
  • This application provides a laser projection device, including: a display control circuit, a laser light source, and three sets of laser drive components.
  • the laser light source includes three sets of laser components with different colors.
  • the three sets of laser components and the three sets of laser drive components are one by one. correspond;
  • the display control circuit is respectively connected with each laser driving component, and is used to output three enable signals corresponding to the three primary colors of each frame of the multi-frame display image, and transmit the three enable signals to the corresponding And, output three current control signals corresponding to the three primary colors of each frame of image one-to-one, and transmit the three current control signals to the corresponding laser drive components, where each laser component corresponds to The magnitude of the current control signal corresponding to at least two frames of display images is different;
  • Each laser drive component is connected to a corresponding laser component, and is used to provide the laser component to which it is connected with a drive current corresponding to the laser component, and adjust the corresponding current control signal according to the current working current and light-emitting brightness of the laser component;
  • Each laser component is used to emit light under the driving of the corresponding laser driving component.
  • FIG. 1 is a schematic diagram of a partial structure of a light source system provided by an embodiment of the present application
  • FIG. 2 is a schematic structural diagram of a laser projection device provided by an embodiment of the present application.
  • FIG. 3 is a schematic structural diagram of a laser driving assembly provided by an embodiment of the present application.
  • FIG. 4 is a schematic structural diagram of a laser driving assembly provided by an embodiment of the present application.
  • FIG. 5 is a schematic structural diagram of a current adjustment circuit provided by an embodiment of the present application.
  • FIG. 6 is a schematic structural diagram of a driving sub-circuit provided by an embodiment of the present application.
  • FIG. 7 is a graph of the relationship between current and brightness corresponding to the corresponding relationship table of PWM value, current and brightness;
  • FIG. 8 is a schematic structural diagram of a voltage regulation sub-circuit provided by an embodiment of the present application.
  • FIG. 9 is a schematic diagram of a partial structure of a laser driving assembly provided by an embodiment of the present application.
  • FIG. 10 is a schematic structural diagram of a voltage follower provided by an embodiment of the present application.
  • Fig. 11 is a schematic diagram of waveforms of a PWM signal before and after being processed by a repeater according to an embodiment of the present application;
  • FIG. 12 is a schematic structural diagram of a laser driving assembly provided by an embodiment of the present application.
  • FIG. 13 is a graph of the relationship between the grayscale value of the input signal and the screen brightness provided by an embodiment of the present application.
  • 15 is a graph of the relationship between the grayscale value of the input signal and the screen brightness provided by an embodiment of the present application.
  • FIG. 16 is a block diagram of a laser projection device provided by an embodiment of the present application.
  • FIG. 17 is a block diagram of a laser projection device provided by an embodiment of the present application.
  • FIG. 18 is a block diagram of a laser projection device provided by an embodiment of the present application.
  • the current full three-color light source system usually includes two dichroic mirrors 100, a laser light source 200, a reflector 300, a condenser lens 400, a diffuser 500 and a light rod 600.
  • the laser light source 200 includes a red laser component 210 for emitting red laser, a green laser component 220 for emitting green laser, and a blue laser component 230 for emitting blue laser, and the laser component includes at least one Laser.
  • the red laser light emitted by the red laser assembly 210 can be transmitted to the condenser lens 400 through a dichroic mirror 110.
  • the green laser light emitted by the green laser component 220 may first be reflected by the reflecting mirror 300 to another dichroic mirror 120, then be reflected by the other dichroic mirror 120 to a dichroic mirror 110, and then pass through the one dichroic mirror 120.
  • the dichroic mirror 110 reflects to the condenser lens 400.
  • the blue laser light emitted by the blue laser assembly 230 may be transmitted to a dichroic mirror 110 through another dichroic mirror 120, and then reflected to the condenser lens 400 through the one dichroic mirror 110.
  • the laser light irradiated on the condenser lens 400 is condensed by the condenser lens 400 and then irradiated on the diffusion wheel 500.
  • the laser light irradiated on the diffuser wheel 50 is irradiated into the light rod 600 after being homogenized by the diffuser wheel 500, and under the uniform light effect of the light rod 600, a three-color light source is realized.
  • the types and numbers of lasers included in the full three-color light source system have increased, and the light-emitting principles and performance of different color lasers are also different.
  • the brightness of the laser and the color temperature of the composition will occur. Changes, resulting in poor image display effect of laser projection equipment.
  • FIG. 2 shows a schematic structural diagram of a laser projection device provided by an embodiment of the present application.
  • the laser projection equipment includes:
  • the display control circuit 10, the laser light source 20 and the three groups of laser driving components 30, the laser light source 20 includes three groups of laser components 201 with different colors, and the three groups of laser components 201 correspond to the three groups of laser driving components 30 one to one.
  • the display control circuit 10 is respectively connected to three groups of laser drive components 30, and is used to output three enable signals corresponding to the three primary colors of each frame of the multi-frame display image, and transmit the three enable signals separately To the corresponding laser drive assembly 30. And, outputting three current control signals one-to-one corresponding to the three primary colors of each frame of image, and respectively transmitting the three current control signals to the corresponding laser driving components 30, wherein the current control signal corresponding to each group of laser components is Corresponding to at least two frames of different sizes when displaying images.
  • the current control signal may be a pulse width modulation (PWM, Pulse Width Modulation) signal
  • Each group of laser drive components 30 is connected to a corresponding group of laser components 201, and is used to provide the laser components to which it is connected with a drive current corresponding to the laser components, and adjust the corresponding laser components according to the working current and light-emitting brightness of the laser components.
  • the current control signal is used to control the laser components to which it is connected with a drive current corresponding to the laser components, and adjust the corresponding laser components according to the working current and light-emitting brightness of the laser components.
  • Each group of laser components 201 is used to emit light under the driving of the corresponding laser driving component 30.
  • the laser light source 20 includes a red laser component 201a, a green laser component 100b, and a blue laser component 100c.
  • the display control circuit 01 can output the red PWM signal R_PWM corresponding to the red laser component based on the red primary color component of the image to be displayed, and output the green PWM signal G_PWM corresponding to the green laser component based on the green primary color component of the image to be displayed.
  • the blue primary color component outputs the blue PWM signal B_PWM corresponding to the blue laser component.
  • the display control circuit 01 can output the enable signal R_EN corresponding to the red laser component based on the lighting time of the red laser component in the driving cycle, and output the same as the green laser component based on the lighting time of the green laser component in the driving cycle.
  • the enable signal G_EN corresponding to the component outputs the enable signal B_EN corresponding to the blue laser component based on the lighting time of the blue laser component in the driving period.
  • the red laser assembly 100a, the green laser assembly 100b, and the blue laser assembly 100c are respectively connected to the corresponding laser driving assembly 30.
  • the display control circuit in the laser projection device can output three current control signals based on the three primary color components of the image to be displayed, and output three enable signals
  • the three enable signals and the three current control signals are respectively transmitted to the corresponding laser driving components, so that each group of laser driving components can provide the corresponding driving current of the laser component to the laser component connected to it.
  • the laser projection device can support variable-brightness laser components, effectively improving the image display effect of the laser projection device.
  • the laser drive component can adjust the corresponding current control signal according to the working current and light-emitting brightness of the laser component, feedback adjustment of the light-emitting brightness of the laser component is realized, and the white balance change of the image display caused by the attenuation of the laser component is avoided. Therefore, the change in color temperature caused by the change in white balance is avoided, and therefore, the image display effect of the laser projection device is more effectively improved.
  • FIG. 3 is a schematic structural diagram of a laser driving assembly provided by an embodiment of the present application.
  • the laser driving component 30 may include: a driving circuit 301 and a current adjusting circuit 302.
  • the driving circuit 301 is respectively connected to the current adjusting circuit 302 and the driving output terminal V outa .
  • the driving output terminal V outa is used to connect the laser assembly 201.
  • the driving circuit 301 is used to drive the output terminal based on the received current control signal and enable signal. V outa loads the driving voltage.
  • the current adjusting circuit 302 is respectively connected to the driving circuit 301 and the detection node in the current path of the laser component 201 for detecting the working current of the laser component 201, and according to the current working current of the laser component 201, the luminous brightness of the laser component 201 and the laser The initial brightness of the component 201 adjusts the current control signal.
  • FIG. 4 is a schematic structural diagram of a laser driving assembly provided by an embodiment of the present application.
  • each driving circuit 301 includes: a driving sub-circuit 3011, a voltage adjusting sub-circuit 3012, a switch sub-circuit 3013, and a current adjusting circuit 302.
  • the driving sub-circuit 3011 is respectively connected to the voltage regulating sub-circuit 3012, the switching sub-circuit 3013 and the driving output terminal V outa .
  • the driving sub-circuit 3011 is used to adjust the output voltage direction of the voltage output terminal of the voltage regulating sub-circuit 3012 based on the received current control signal
  • the drive output terminal loads the drive voltage and transmits the received enable signal to the switch sub-circuit 3013.
  • the driving sub-circuit 3011 is also used to output a control signal to the voltage adjusting sub-circuit 3012 according to the output voltage.
  • the voltage adjustment sub-circuit 3012 is used to adjust the output voltage to the rated voltage of the laser assembly 201 under the control of the control signal.
  • the switch sub-circuit 3013 is connected in series in the current path of the laser assembly 201, and is used to control the current path to be turned on when the received enable signal is at an effective potential.
  • the current adjusting circuit 302 is respectively connected to the detection node in the current path of the driving sub-circuit 3011 and the laser component 201, and is used to detect the working current of the laser component 201, and according to the working current, the luminous brightness of the laser component 201 and the initial stage of the laser component 201 Brightness, adjust the current control signal.
  • the current adjusting circuit 302 can determine the brightness difference between the initial brightness of the laser group 201 and the emission brightness, and determine the current value that the laser component 201 needs to increase according to the brightness difference. In turn, the current control signal can be adjusted according to the current value.
  • FIG. 5 is a schematic structural diagram of a current adjustment circuit provided by an embodiment of the present application.
  • the current adjusting circuit 302 includes: an amplifying sub-circuit 3021 and a processing sub-circuit 3022.
  • the amplifying sub-circuit 3021 is respectively connected to the detection node E and the processing sub-circuit 3022 in the current path of the laser component 201, and is used to convert the detected working current of the laser component 201 into a working voltage, amplify the working voltage, and convert the amplified The operating voltage is transmitted to the processing sub-circuit 3022.
  • the processing sub-circuit 3022 is connected to the driving sub-circuit 3011, and is used to output a current control signal according to the amplified working voltage, the light-emitting brightness of the laser assembly, and the initial brightness of the laser assembly.
  • the processing sub-circuit 3022 may be a microcontroller unit (Microcontroller Unit, MCU), also known as a single-chip microcomputer.
  • MCU Microcontroller Unit
  • the amplifying sub-circuit 3021 may include: a first operational amplifier A1, a first resistor (also called a sampling power resistor) R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.
  • the non-inverting input terminal (also called the positive terminal) of the first operational amplifier A1 is connected to one end of the second resistor R2, and the inverting input terminal (also called the negative terminal) of the first operational amplifier A1 is connected to one end and the first terminal of the third resistor R3 respectively.
  • One end of the four resistors R4 is connected, and the output end of the first operational amplifier A1 is respectively connected to the other end of the fourth resistor R4 and the processing sub-circuit 3022.
  • One end of the first resistor R1 is connected to the detection node E, and the other end of the first resistor R1 is connected to the reference power terminal.
  • the other end of the second resistor R2 is connected to the detection node E, and the other end of the third resistor R3 is connected to the reference power terminal.
  • the first operational amplifier A1 may further include two power terminals, one of which is connected to the power terminal VCC1, and the other power terminal may be connected to the reference power terminal.
  • the anode of the laser assembly 201 may be connected to the drive output terminal V outa , and the cathode may be connected to the input terminal of the switch sub-circuit 3013.
  • the output terminal of the switch sub-circuit 3013 can be connected to the detection node E. That is, one end of the first resistor R1 can be connected to the output end of the switch sub-circuit 3013.
  • the input end of the switch sub-circuit 3013 can be connected to the drive output end V outa , and the output end of the switch sub-circuit 3013 can be connected to the anode of the laser assembly 201 .
  • the negative electrode of the laser assembly 201 can be connected to the detection node E. That is, one end of the first resistor R1 can be connected to the negative electrode of the laser component 201.
  • the voltage V i to the end of the first resistor R1 (i.e., the detection node E) through the non-inverting input of a second resistor R2 is transmitted to the first operational amplifier A1
  • the terminal is amplified by N times by the first operational amplifier A1 and output.
  • the N is the magnification of the first operational amplifier A1, and N is a positive number.
  • the magnification N can make the value of the voltage V fb output by the first operational amplifier A1 an integer multiple of the value of the operating current of the laser assembly.
  • the value of the voltage V fb may be equal to the value of the operating current, so that the processing sub-circuit 3022 can determine the operating current of the laser assembly according to the amplified operating voltage.
  • the input and output voltage amplification formula of the first operational amplifier A1 is: V i is the input voltage of the first operational amplifier A1, and V fb is the output voltage of the first operational amplifier A1.
  • the amplification factor N of the first operational amplifier A1 satisfies:
  • the processing sub-circuit 3022 may also be connected to a brightness sensor arranged around the laser component, and the brightness sensor is used to detect the brightness of the laser component and transmit the brightness to the processing sub-circuit 3022.
  • the processing sub-circuit 3022 may obtain the brightness of the laser component detected by the brightness sensor when the laser component is started for the first time, and store the brightness as the initial brightness.
  • the processing sub-circuit 3022 can obtain the light-emitting brightness of the laser component detected by the brightness sensor in real time or periodically.
  • the processing sub-circuit 3022 may also have a digital-to-analog conversion function.
  • the pin corresponding to the digital-to-analog conversion function receives the voltage V fb transmitted from the amplifying sub-circuit, and the processing sub-circuit 3022 can then convert the voltage V fb into the work of the laser assembly. Current. After that, the processing sub-circuit 3022 can superimpose the operating current with the current value that needs to be increased, and output a current control signal based on the superimposed current value, thereby realizing the adjustment of the current control signal.
  • the brightness of the laser light emitted by the laser assembly will decay over time, and due to the different light emitting principles of the laser assembly of different colors, the brightness of the laser light emitted by the laser assembly of different colors is The degree of attenuation is different, so that the color of the laser light emitted by the laser light source changes, and the color temperature of the laser light changes.
  • the degree of attenuation of the brightness of the laser light emitted by the blue laser assembly is smaller than the degree of attenuation of the brightness of the laser light emitted by the red laser assembly and the green laser assembly.
  • the current adjusting circuit 302 can form a closed loop with the driving sub-circuit 3011, the voltage adjusting sub-circuit 3012, and the switching sub-circuit 3013 to realize feedback adjustment of the driving current of the laser assembly, so that the current adjusting circuit can pass the laser
  • the laser assembly emits light.
  • FIG. 6 is a schematic structural diagram of a driving sub-circuit provided by an embodiment of the present application.
  • the driving sub-circuit 3011 includes: a driving chip U and a current detection resistor R0.
  • the driving chip U is respectively connected to the voltage output terminal V outb of the voltage regulating sub-circuit 3012, the switch sub-circuit 3013, the current regulating circuit 302 and the driving output terminal V outa .
  • One end of the current detection resistor R0 is connected to the voltage output terminal V outb
  • the other end of the current detection resistor R0 is connected to the drive output terminal V outa .
  • the driving chip U can detect the current loaded on the current detection resistor R0, and adjust the current loaded on the current detection resistor R0 to the driving current of the corresponding laser component.
  • the drive current I can satisfy:
  • the driving chip U can determine the driving current (that is, the value of the driving current) corresponding to the laser assembly in a variety of ways. In an optional manner, after receiving the current control signal, the driving chip U calculates the value of the driving current corresponding to the laser component through the first preset algorithm. In another optional manner, the driving chip U prestores the corresponding relationship between the current control signal and the current. After the driver chip U receives the current control signal, the corresponding driving current can be obtained by querying the corresponding relationship. For example, when the current control signal is a PWM signal, the corresponding relationship between the current control signal and the current may be characterized by the corresponding relationship between the PWM value and the current. Please refer to Table 1 and Figure 7.
  • Table 1 shows the corresponding relationship between PWM value, current and brightness (in actual applications, the driver chip U only needs to pre-store the corresponding relationship between PWM value and current).
  • Figure 7 is A graph of the relationship between current and brightness corresponding to the correspondence table. It can be seen from Fig. 7 that there is a linear relationship between current and brightness. Generally, the greater the current, the greater the brightness. Therefore, the brightness of the laser assembly can be effectively adjusted by adjusting the current of the laser assembly. For example, when the PWM value of the received PWM signal is 1023, the drive current obtained by looking up the table 1 is 2.6A, and the current loaded on the current detection resistor R0 is adjusted to 2.6A. The brightness of the final laser assembly is 2540lumen (lumens).
  • the current control signal received by the driving chip U may be output by the above-mentioned display control circuit 10, or after the current adjustment circuit 302 in the laser driving assembly 30 adjusts the current control signal. owned. Since the attenuation process of the laser assembly is relatively slow, the current control signal provided by the display control circuit 10 is usually the main and the current control signal provided by the current adjustment circuit 302 is auxiliary, that is, the display control circuit 10 and the current adjustment circuit 302 can alternate The current control signal is provided to the driving chip U.
  • the display control circuit 10 can stop providing the current control signal to the driving chip U every interval adjustment period, and the current adjustment circuit 302 provides the current control signal to the driving chip U.
  • the display control circuit 10 may send a start control signal to the current adjustment circuit 302 (for example, the processing sub-circuit 3022 of the current adjustment circuit 302) every interval adjustment period. After the display control circuit 10 sends the start control signal, it can stop providing the current control signal to the driving chip U. After receiving the start control signal, the current adjusting circuit 302 can provide a current control signal to the driving chip U.
  • the adjustment period can be 1 month, 3 months, or 1 year.
  • the time period during which the display control circuit 10 stops providing the current control signal to the driving chip U (that is, the time period during which the current adjustment circuit 302 provides the current control signal) can be 1 minute, 3 minutes, or 5 minutes.
  • the aforementioned voltage output circuit 302 can be divided into a boost circuit or a step-down circuit according to different working modes.
  • the boost circuit is a circuit that increases the input voltage VIN to the rated voltage Vo of the laser component, VIN ⁇ Vo
  • the step-down circuit is a circuit that decreases the input voltage VIN to the rated voltage Vo of the laser component, VIN>Vo. Since the initial input voltage VIN of the boost circuit is lower than that of the buck circuit, if the boost circuit has a fault such as a short circuit, the lower initial input voltage Vi does not exceed the rated voltage Vo of the laser component, and will not cause damage to the laser component. It will not cause the risk of electric shock to the human body. Therefore, compared with the step-down circuit, the booster circuit is less likely to damage the equipment, and the safety is higher.
  • the voltage regulating sub-circuit 3012 may be a boosting sub-circuit 3012.
  • the boosting sub-circuit 3012 is also connected to the input power terminal VIN for boosting the input voltage provided by the input power terminal VIN to the rated voltage Vo under the control of the control signal.
  • FIG. 8 is a schematic structural diagram of a voltage adjustment sub-circuit provided by an embodiment of the present application.
  • the boost sub-circuit 3012 may include: an inductor L, a first field effect transistor Q1, a diode D, a capacitor C, a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7.
  • One end of the inductor L is connected to the driving sub-circuit 3011 and the input power terminal VIN, and the other end of the inductor L is connected to the first pole of the first field effect transistor Q1 and the anode of the diode D, respectively.
  • the gate of the first field effect transistor Q1 is connected to the driving sub-circuit 3011, and the second pole of the first field effect transistor Q1 is respectively connected to the driving sub-circuit 3011 and one end of the seventh resistor R7.
  • the cathode of the diode D is respectively connected to one end of the capacitor C, one end of the fifth resistor R5, and the voltage output terminal V outb of the voltage regulation sub-circuit 3012.
  • the other end of the fifth resistor R5 is respectively connected to one end of the driving sub-circuit 3011 and the sixth resistor R6.
  • the other end of the capacitor C, the other end of the sixth resistor R6, and the other end of the seventh resistor R7 are all connected to the reference power terminal.
  • the boost sub-circuit 3012 by boosting the voltage of the input power terminal VIN to the rated voltage Vo, it is output from the voltage output terminal V outb of the voltage adjustment sub-circuit 3012.
  • the voltage of the input power terminal VIN can also be boosted to (Vo+Vtb), where Vtb is the specified threshold.
  • the node F between the fifth resistor R5 and the sixth resistor R6 and the resistance values of the fifth resistor R5 and the sixth resistor R6 are set The rated voltage Vo of the boost sub-circuit 3012.
  • the rated voltage Vo is: V b is the reference voltage of the node F, that is, the reference voltage of the driving chip U in the driving sub-circuit 3011. Since the reference voltage V b and the rated voltage Vo of the driving chip U are usually constant values, the resistance values of the fifth resistor R5 and the sixth resistor R6 can be determined by the reference voltage V b and the rated voltage Vo.
  • the working process of the boost sub-circuit 3012 shown in FIG. 8 can be divided into a charging process and a discharge process.
  • the working principle of the boost circuit is as follows:
  • the first FET Q1 is turned on, the input power terminal VIN continues to store energy into the inductor L, the current on the inductor L increases linearly, and at the same time, the diode D is reversely blocked to prevent the voltage of the capacitor C from discharging the reference power terminal O ( When the reference power terminal O is the reference ground, it is discharged to the ground), so the DC power continuously charges the inductor L to store energy, forming a current loop h1.
  • the first field effect transistor Q1 is turned off, which is equivalent to the above-mentioned current loop h1 is open. Since the current of the inductor L cannot change suddenly, the current flowing through the inductor L is slowly discharged until it is zero. Since the circuit of the current loop h1 has been disconnected, the inductor L can only charge the capacitor C through the diode D, so that the electromotive force of the capacitor C continues to rise, forming a current loop h2.
  • the grid of the first field effect tube Q1 is controlled so that the first field effect tube Q1 is constantly turned on and off at a certain frequency
  • the booster circuit 203 is controlled to continuously charge and discharge, so that the voltage across the capacitor C continues to rise until it reaches the set rated voltage Vo, thereby completing the boosting of the booster circuit.
  • the gate of the first field effect transistor Q1 can be controlled by comparing the actual voltage of the node F with the reference voltage of the node F, so that the first field effect transistor Q1 is continuously turned on and off at a certain frequency.
  • the first field effect transistor Q1 may be an N-Metal-Oxide-Semiconductor (NMOS) tube.
  • NMOS N-Metal-Oxide-Semiconductor
  • FIG. 8 assumes that the driving chip U controls the turn-on and turn-off of the first field effect transistor Q1, and sets the reference voltage V b of the node F between the fifth resistor R5 and the sixth resistor R6.
  • the driving chip U can perform turn-on and turn-off control of the first field effect transistor Q1 at a frequency above 100 kHz (kilohertz), that is, the switching frequency is greater than or equal to 100 kHz.
  • This switching frequency can minimize the size of discrete components, such as inductors, diodes, etc., and maintain a high driving efficiency, so that the temperature rise of the discrete components is smaller, the heat is easier to control, and the drive circuit is prevented from overheating. .
  • FIG. 9 is a schematic diagram of a partial structure of a laser driving assembly provided by an embodiment of the present application.
  • the switch sub-circuit 3013 includes: a second field effect transistor Q2.
  • the gate of the second switching field effect transistor Q2 is connected to the driving sub-circuit 3011, and the first pole and the second electrode of the second field effect transistor Q2 are respectively connected to two nodes in the current path of the laser assembly 201.
  • the gate of the second field effect tube Q2 is connected to the driving chip U in the driving sub-circuit 3011
  • the first electrode of the second field effect tube Q2 may be connected to one end (for example, the negative electrode) of the laser assembly 201
  • the second pole of the tube Q2 can be connected to one end of the first resistor R1.
  • the first pole of the second field effect transistor Q2 may be the input terminal of the switch sub-circuit 3013
  • the second pole of the second field effect transistor Q2 may be the output terminal of the switch sub-circuit 3013.
  • the gate of the second field effect tube Q2 is connected to the driving chip U in the driving sub-circuit 3011, the first electrode of the second field effect tube Q2 may be connected to the other end (for example, the anode) of the laser assembly 201, and the second field effect The second pole of the tube Q2 can drive the output terminal V outa to be connected.
  • the level signal input by the gate of the second field effect transistor Q2 is controlled to be high relative to the level signal of the source, and the second field effect transistor Q2 is turned on ,
  • the current path of the laser component 201 is turned on to form a current loop h3, and the laser component 201 lights up.
  • the enable signal received by the driving chip U is at an invalid potential
  • the level signal input by the gate of the second field effect transistor Q2 is controlled to be low relative to the level signal of the source, and the second field effect transistor Q2 is turned off
  • disconnected the current path of the laser assembly 201 is cut off, and the laser assembly 201 is extinguished.
  • the laser driving component corresponding to the red laser component is taken as an example for description. Assuming that the driving period of each frame of image is T, the high level is the effective potential, and the on-time (i.e., lighting duration) of the red laser component in a driving period T is t, then the enable signal EN_R corresponding to the red laser component The high level duration in a driving period T is t. After the enable signal EN_R is input to the driving chip U, the switch sub-circuit 3013 is controlled to turn on and off, so as to realize the lighting and extinguishing of the red laser component control.
  • the second field effect transistor Q2 is turned on, the current path of the red laser component is turned on, and the light-on duration of the red laser component is t.
  • the enable signal EN_R is at a low level, the second FET Q2 is turned off, the current path of the red laser component is not turned on, and the red laser component does not work, the duration of the red laser component extinguishing is T-t.
  • the laser assembly 201 includes n lasers connected in series, namely lasers LD 1 to LDn.
  • the lasers LD 1 to LDn do not belong to the switching sub-circuit 3013.
  • the second field effect transistor Q2 can be an N-Metal-Oxide-Semiconductor (NMOS) tube, and the on-off time of the second field effect transistor Q2 can reach ns (nanoseconds). )level.
  • NMOS N-Metal-Oxide-Semiconductor
  • the response speed of the laser drive component to the on-off current of the laser component is faster, and the accuracy is high, which reduces the probability of light color mixing caused by the delay of the laser component switching, and provides a laser TV display effect, which is a real-time basis
  • the display image adjusts the driving voltage applied to the laser assembly, that is, adjusts the laser
  • the drive current provides the hardware basis.
  • the current control signal may be a PWM signal.
  • the PWM signal will have a certain attenuation during transmission, and the attenuation will cause the amplitude of the PWM signal (also called high level amplitude) to be lower than the effective value.
  • the set full-scale amplitude The embodiment of the application provides a voltage follower, which can adjust the received PWM signal whose amplitude is lower than the full-scale amplitude to a PWM signal whose amplitude is the full-scale amplitude without changing the duty cycle of the PWM signal. In this way, signal attenuation caused by signal transmission is avoided, the accuracy of the current control signal input to the driving chip is ensured, and the subsequent driving accuracy is improved.
  • the laser driving component 30 further includes: a voltage follower (also called a relay) 3014, and the voltage follower 3014 is connected to the driving sub-circuit 3011 for comparing the received signal with the laser component 201 The corresponding current control signal is processed, and the processed current control signal is output to the driving sub-circuit 3011.
  • a voltage follower also called a relay
  • Fig. 10 is a schematic structural diagram of a voltage follower provided by an embodiment of the present application.
  • the voltage follower 3014 includes: a second operational amplifier A2, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, and an eleventh resistor R11.
  • the non-inverting input end of the second operational amplifier A2 is connected to one end of the eighth resistor R8, the inverting input end of the second operational amplifier A2 is connected to one end of the ninth resistor R9, and the output end of the second operational amplifier A2 is connected to the ninth resistor respectively.
  • the other end of R9 is connected to one end of the tenth resistor R10.
  • the other end of the eighth resistor R8 is used to receive the current control signal.
  • the other end of the tenth resistor R10 is respectively connected to one end of the driving sub-circuit 3011 and the eleventh resistor R11.
  • the other end of the eleventh resistor R11 is connected to the reference power terminal.
  • the resistance of the eighth resistor R8 and the ninth resistor R9 are the same.
  • the second operational amplifier A2 may also include two power terminals, one of which is connected to the power terminal VCC2, and the other power terminal is connected to the reference power terminal.
  • the tenth resistor R10 and the eleventh resistor R11 may be voltage dividing resistors, so that the voltage output by the voltage follower can be Match the input voltage requirements of the corresponding pins of the drive chip to ensure the normal operation of the laser drive components.
  • the node G between the tenth resistor R10 and the eleventh resistor R11 is used to output the current control signal after the voltage dividing process, and the voltage output by the node G is the rated voltage of the driving chip.
  • the resistance values of the tenth resistor R10 and the eleventh resistor R11 are set according to the rated voltage of the voltage follower and the driving chip.
  • the voltage follower has the characteristics of high input impedance and low output impedance. To a certain extent, it can avoid the signal loss caused by the higher output impedance and the lower input impedance of the next stage, which plays a role of linking up and down, that is, buffering. Because the voltage follower has the characteristics of high input impedance and low output impedance, it presents a high-impedance state to the upper-level circuit and a low-impedance state to the next-level circuit. It is often used in the intermediate stage to isolate the front and rear circuits and eliminate The mutual influence between them. In the embodiment of the present application, the voltage follower can isolate various noises generated by the circuit (for example, the display control circuit) driving the front end of the chip, and therefore can improve the accuracy of the laser driving component.
  • the circuit for example, the display control circuit
  • FIG. 12 shows a schematic structural diagram of a laser driving assembly provided by an embodiment of the present application.
  • the driving chip U in the driving sub-circuit 3011 includes: a first pin EN, a second pin CTRL, a third pin ISN, a fourth pin ISP, a fifth pin V IN and a sixth pin.
  • the first pin EN is connected to the display control circuit, and is used to receive the enable signal transmitted by the display control circuit.
  • the second pin CTRL is respectively connected to the display control circuit and the current adjustment circuit 302 through the voltage follower 3014 for receiving the current control signal.
  • the second pin CTRL is connected to the other end of the tenth resistor in the voltage follower 3014, and the other end of the eighth resistor R8 in the voltage follower 3014 is respectively connected to the display control circuit and the processing sub-circuit of the current adjustment circuit 302 .
  • the third pin ISN is connected to the driving output terminal V outa
  • the fourth pin ISP is connected to the voltage output terminal V outb of the voltage regulation sub-circuit 3012.
  • the fifth pin V IN is connected to the input power terminal VIN, and is used to provide power to the driving chip U.
  • the sixth pin FB is connected to the node F in the voltage regulation sub-circuit 3012.
  • the seventh pin GATE is connected to the gate of the first field effect transistor Q1 in the voltage regulation sub-circuit 3012.
  • the eighth pin SENSE is respectively connected to one end of the seventh resistor in the voltage regulation sub-circuit 3012 and the second pole of the first field effect transistor Q1.
  • the eighth pin SENSE is used to collect the current of the boost circuit by detecting the voltage between the second pole of the first FET Q1 and the seventh resistor. When the collected current is greater than the set current upper limit threshold, drive The chip U will control the seventh pin GATE to turn off the current loop of the boost circuit. In this way, the overcurrent protection of the boost circuit is realized based on the collected current.
  • the ninth pin ENOUT is connected to the gate of the second field effect transistor Q2.
  • the reference power terminal may be a ground terminal.
  • the display control circuit in the laser projection device can output three current control signals based on the three primary color components of the image to be displayed, and output three enable signals
  • the three enable signals and the three current control signals are respectively transmitted to the corresponding laser drive components, so that each of the laser drive components can provide the laser components to which it is connected with a drive current corresponding to the laser component.
  • the laser projection device can support variable-brightness laser components, effectively improving the image display effect of the laser projection device .
  • the laser drive component can adjust the corresponding current control signal according to the working current and light-emitting brightness of the laser component, feedback adjustment of the light-emitting brightness of the laser component is realized, and the white balance change of the image display caused by the attenuation of the laser component is avoided. Therefore, the change in color temperature caused by the change in white balance is avoided, and therefore, the image display effect of the laser projection device is more effectively improved.
  • the contrast of laser projection equipment is usually divided into static contrast and dynamic contrast.
  • Static contrast usually refers to the contrast calculated by the contrast algorithm formulated by the American National Standards Institute (ANSI), which refers to the brightness of the white area and the black area in a picture (that is, the same frame of image) ratio.
  • ANSI American National Standards Institute
  • Dynamic contrast refers to the light-dark ratio of the same frame of image during the display process, which is related to the brightness of the laser light source during the display process, that is, the brightest white area and the darkest black area of the image during the display process. Brightness ratio.
  • the dynamic contrast C satisfies:
  • L w luminance for one frame of image during the display of the brightest white region L B luminance for an image display during the black region darkest.
  • the dynamic contrast formula when L w reaches the maximum value, the dynamic contrast can be improved by reducing the value of L B.
  • the actual display brightness of the image of the laser projection device is usually determined by two factors. One factor is the brightness of the laser light source, and the other factor is the grayscale value of the image (that is, the brightness of the image itself). Superposition can finally determine the actual display brightness of a frame of image. Therefore, the display effect can be optimized by adjusting the ratio of the two factors.
  • the brightness of the image itself in the video displayed by the laser projection device is constantly changing based on its content.
  • the laser light source can be adjusted according to the brightness of the image itself to adjust the actual display brightness of the image.
  • the brightness of the laser light source can be reduced to make the actual display brightness of the frame of image lower than its own brightness.
  • the lower limit of the actual display brightness of the laser projection device when displaying images that is, the lowest actual display brightness (L B )
  • L B lowest actual display brightness
  • the power consumption of the laser projection device is also reduced.
  • the laser projection device provided by the embodiment of the present application can improve the dynamic contrast of the laser projection device without changing the actual display brightness of the image.
  • the principle of image display is: separately processing the brightness of the laser light source and the grayscale value of the image to be displayed to enhance the detail expression of the image, and then reduce the brightness of the light source and increase the laser light on the premise that the brightness of the displayed image remains unchanged.
  • the dynamic contrast of the projection device In order to facilitate readers’ understanding, the embodiments of the present application take FIGS. 13 to 15 as examples to illustrate the image display principles involved in the embodiments of the present application:
  • FIGS. 13 to 15 show the relationship between the input signal grayscale value (also called the display grayscale value or the brightness of the image itself) and the screen brightness (that is, the actual display brightness).
  • the abscissa is the grayscale value of the input signal
  • the ordinate is the screen brightness.
  • the power of the laser light source (because the power of the laser light source is proportional to the brightness of the laser light source, in the embodiment of this application, it is assumed that the power of the laser light source is equivalent to the laser light source).
  • the brightness of the light source is a standard quantity (that is, the reference quantity).
  • the unit is one.
  • the curve of the gray scale value of the input signal of the laser projection device and the screen brightness (that is, the Horse curve) is the solid line in FIG. 13.
  • the input signal grayscale value of a frame of image A currently displayed is 160
  • the corresponding screen brightness is 96.
  • the input signal grayscale value of this frame of image A is increased by D times.
  • Image A is transformed into image A', and the screen brightness corresponding to this image A'is 192.
  • the screen brightness can be reduced to 96 by reducing the power of the laser light source, thereby converting image A'into image A.
  • the laser projection device provided by the embodiment of the present application can expand the display grayscale value range of the image, that is, increase the display grayscale.
  • the upper limit value of the value therefore, enhances the detailed expression of the image, and at the same time, under the premise of ensuring that the actual display brightness of the image A remains unchanged, the brightness of the laser light source is reduced, the contrast is increased, and the power consumption is reduced.
  • the laser projection device further includes: a light modulation device 40, and the light modulation device 40 may be a digital micromirror device (Digital Micromirror Device, DMD) or a liquid crystal on silicon (Liquid Crystal on Silicon, LCOS).
  • DMD Digital Micromirror Device
  • LCOS liquid crystal on Silicon
  • the display control circuit 10 includes: an algorithm processor 101 and a control processing module 102, the algorithm processor 101 is connected to the control processing module 102, and the control processing module 102 is also connected to the laser driving assembly 30 and the light modulation device 40, respectively.
  • the algorithm processor 101 may be implemented by using a field programmable gate array (Field-Programmable Gate Array, FPGA).
  • the algorithm processor 101 is configured to determine the gain value ⁇ of each frame image, ⁇ 1 according to the image display data (for example, grayscale value) of each frame image in the multi-frame display image.
  • the image display data of each frame of image can reflect the basic distribution and basic tone of each frame of image color.
  • the 4K data can be V-by-One (an image-oriented transmission
  • the developed digital interface standard) signal is input to the algorithm processor 101.
  • the algorithm processor 101 is also used to send the image display data and the current control signal corresponding to the laser component to the control processing module 102.
  • each of the foregoing current control signals is used to indicate the adjusted brightness of the corresponding laser component
  • the adjusted brightness is 1/ ⁇ of the brightness before adjustment
  • the image display data is used to indicate the gray scale of each frame of image after adjustment.
  • the gray scale value after adjustment is ⁇ times of the gray scale value before adjustment.
  • the control processing module 102 is used to send image display data and current control signals corresponding to the laser assembly to the light modulation device 40.
  • the light modulation device 40 is used for modulating the beam of the laser light source based on the image display data to output an image beam, and project the image beam onto the display screen to realize the display of each frame of image.
  • the laser projection device may further include: a plurality of optical lenses located between the light modulation device 40 and the display screen, and the plurality of optical lenses are used to transmit, reflect and/or transmit the image beam After refraction, it is projected onto the screen.
  • the display control circuit 10 can adjust the brightness of the laser light source in real time based on the gain value ⁇ of each frame of image, that is, the change of each frame of image, so as to achieve dynamic contrast.
  • the first switch transistor is a MOS tube, such as an NMOS tube
  • the on-off time of the light source switch circuit reaches the ns (nanosecond) level
  • the on-off time of the laser drive component reaches ⁇ s ( Microsecond) level
  • the current response speed of the laser assembly is fast and the accuracy is high
  • the laser drive assembly can quickly and accurately respond to the changes in the brightness of each pixel of the image, and the brightness of the laser assembly can be changed from 0 to rated
  • the arbitrary adjustment of the brightness corresponding to the current value reduces the serious image quality problem of color mixing caused by the slow reaction speed of the laser drive component of the multiple primary colors.
  • This drive circuit is the basis for achieving high dynamic contrast, that is, it
  • the image display data of laser projection equipment becomes larger and larger.
  • the image display data is 4K data, that is, data with a pixel resolution of 4096 ⁇ 2160, and the display control circuit 10 uses only one processing
  • the processor is likely to cause low processing efficiency of the processor. Therefore, an embodiment of the present application proposes a manner in which the master and slave processors co-process image display data to improve processing efficiency.
  • control processing module 102 may include a master control processor 1021 and a slave control processor 1022, and the algorithm processor 101 is connected to the master control processor 1021 and the slave control processor 1022, respectively.
  • the master control processor 1021 is also connected to the laser driving assembly 30 and the optical modulation device 40 respectively, and the slave control processor 1022 is also connected to the optical modulation device 40.
  • the algorithm processor 101 is configured to determine the gain value ⁇ of each frame of image, ⁇ 1 according to the grayscale value of each frame of image.
  • the algorithm processor 101 is also configured to send a current control signal and the first sub-data to the main control processor 1021, and send the second sub-data to the slave control processor.
  • the first sub-data and the second sub-data constitute the aforementioned image display data.
  • the first sub-data and the second sub-data are both 60bit (bit) data
  • both the first sub-data and the second sub-data may be low-voltage differential signals (Low- Voltage Differential Signaling, LVDS), where the first sub-data is two-channel west (west) LVDS, and the second sub-data can be two-channel east (east) LVDS.
  • LVDS Low- Voltage Differential Signaling
  • the algorithm processor 101 may output the current control signal in a variety of ways. The following two embodiments of the present application are described as examples.
  • the algorithm processor 101 determines the gain value ⁇ of each frame of image, it calculates the brightness of each group of laser components, and outputs a current control signal based on the brightness through a second preset algorithm.
  • the algorithm processor 101 may pre-store the corresponding relationship between the current control signal and the brightness. After the gain value ⁇ of each frame of image is determined, the algorithm processor 101 calculates the brightness of each group of laser components. , And then query the corresponding relationship according to the calculated brightness to obtain the current control signal corresponding to the laser assembly.
  • the corresponding relationship between the current control signal and the current may be characterized by the corresponding relationship between the PWM value and the brightness.
  • the corresponding relationship can refer to the corresponding relationship between the PWM value and the brightness in Table 1 above.
  • the main control processor 1021 is configured to send a current control signal and an enable signal to the laser driving assembly 30 and send the first sub-data to the optical modulation device 40.
  • the slave control processor 1022 is configured to send the second sub-data to the light modulation device 40.
  • the light modulation device 40 is used for modulating the beam of the laser light source based on the first sub-data and the second sub-data to output an image beam, and project the image beam onto the display screen to realize the display of each frame of image.
  • the laser projection device further includes: a memory 50, a galvanometer drive circuit 60, a galvanometer 70 and a power module 80.
  • the memory 50 is connected to the arithmetic processor 101 for storing image display data. Please refer to FIG. 16 and FIG. 17, that is, the grayscale value of each frame of image after adjustment is stored.
  • the memory is a Double Data Rate (DDR) memory.
  • DDR Double Data Rate
  • the galvanometer drive circuit 60 is respectively connected to the algorithm processor 101 and the galvanometer 70 for driving the galvanometer 70 to vibrate under the control of the algorithm processor 101.
  • the galvanometer 70 may be a 4-dimensional galvanometer, that is, it can vibrate in 4 directions.
  • the power module 80 is used to provide electrical energy for the electrical components, and it is connected to each electrical component in the laser projection device respectively.
  • FIG. 18 is only connected with the main control processor 1021 for schematic illustration.
  • the laser projection equipment may also include: two dichroic mirrors 200, a reflecting mirror 300, a condenser lens 400, a diffuser wheel 500 and a light rod 600, etc.
  • the functions of each element can be referred to FIG. 1, and the implementation of this application I won't repeat this example.

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Abstract

本申请是关于一种激光投影设备，属于投影显示领域。激光投影设备包括：显示控制电路，激光光源和三组激光器驱动组件，激光光源包括颜色互不相同的三组激光器组件，三组激光器组件与三组激光器驱动组件一一对应；显示控制电路分别与每组激光器驱动组件连接，用于输出与每一帧图像的三种基色一一对应的三个使能信号以及三个电流控制信号。每组激光器驱动组件与对应的一组激光器组件连接，用于向其所连接的激光器组件提供激光器组件对应的驱动电流，以及根据激光器组件的工作电流和发光亮度，调节对应的电流控制信号；每组激光器组件用于在对应的激光器驱动电流的驱动下发光。本发明提高了激光投影设备的图像显示效果。

Description

激光投影设备
本申请要求于2019年6月20日提交中国专利局、申请号为201910642281.3，申请名称为“激光投影设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请属于投影显示领域，特别涉及一种激光投影设备。
背景技术
诸如超短焦激光电视等激光投影设备因其具有色彩纯度高、色域大和亮度高等优点，被广泛应用于显示领域。
目前的激光电视包括光源系统以为激光电视提供三色的投影光源。该光源系统通常包括激光光源、荧光轮和滤色轮，该激光光源通常为用于出射蓝色激光的蓝色激光器组件。该蓝色激光时序性地照射至荧光轮的三个不同的区域上，从而产生三色光，该三种颜色的光依次通过滤色轮进行过滤处理，得到纯度更高的三色光。但是，由于该光源系统通过将蓝色激光照射至荧光轮以产生三色光，光饱和度不高，无法更大范围的还原自然界的颜色，随着技术的发展，红色激光器和绿色激光器逐渐成熟，激光投影使用的光源系统转换为全三色激光光源系统，该全三色光源系统的激光光源包括三种颜色的激光器，以便直接产生三基色单色光，有效提高了图像的色域。
但是，全三色光源系统中激光光源包括的激光器种类和数量增多，不同颜色激光器的发光原理和性能也存在不同，随着三色光源的使用，激光器的发光亮度和构成的色彩色温方面会发生变化，导致激光投影设备的图像显示效果较差。
申请内容
本申请提供了一种激光投影设备，包括：显示控制电路，激光光源和三组激光器驱动组件，激光光源包括颜色互不相同的三组激光器组件，三组激光器组件与三组激光器驱动组件一一对应；
显示控制电路分别与每个激光器驱动组件连接，用于输出与多帧显示图像中的每一帧图像的三种基色一一对应的三个使能信号，将三个使能信号分别传输至对应的激光器驱动组件，以及，输出与每一帧图像的三种基色一一对应的三个电流控制信号，将三个电流控制信号分别传输至对应的激光器驱动组件，其中，每个激光器组件对应的电流控制信号在对应至少两帧显示图像时的大小不同；
每个激光器驱动组件与对应的一个激光器组件连接，用于向其所连接的激光器组件提供激光器组件对应的驱动电流，以及根据激光器组件当前的工作电流和发光亮度，调节对应的电流控制信号；
每个激光器组件用于在对应的激光器驱动组件的驱动下发光。
应当理解的是，以上的一般描述和后文的细节描述仅是示例性的，并不能限制本申请。
附图说明
为了更清楚地说明本申请的实施例，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1是本申请实施例提供的一种光源系统的局部结构示意图；
图2是本申请实施例提供的一种激光投影设备的结构示意图；
图3是本申请实施例提供的一种激光器驱动组件的结构示意图；
图4是本申请实施例提供的一种激光器驱动组件的结构示意图；
图5是本申请实施例提供的一种电流调节电路的结构示意图；
图6是本申请实施例提供的一种驱动子电路的结构示意图；
图7是PWM值、电流与亮度的对应关系表所对应的电流与亮度的关系曲线图；
图8是本申请实施例提供的一种电压调节子电路的结构示意图；
图9是本申请实施例提供的一种激光器驱动组件的局部结构示意图；
图10是本申请实施例提供的一种电压跟随器的结构示意图；
图11是本申请实施例提供的一种PWM信号经过中继器处理前后的波形示 意图；
图12是本申请实施例提供的一种激光器驱动组件的结构示意图；
图13是本申请实施例提供的一种输入信号灰阶值、屏幕亮度的关系曲线图；
图14是本申请实施例提供的一种输入信号灰阶值、屏幕亮度的关系曲线图；
图15是本申请实施例提供的一种输入信号灰阶值、屏幕亮度的关系曲线图；
图16是本申请实施例提供的一种激光投影设备的框图；
图17是本申请实施例提供的一种激光投影设备的框图；
图18是本申请实施例提供的一种激光投影设备的框图。
此处的附图被并入说明书中并构成本说明书的一部分，示出了符合本申请的实施例，并与说明书一起用于解释本申请的原理。
具体实施方式
为了使本申请的目的、技术方案和优点更加清楚，下面将结合附图对本申请作进一步地详细描述，显然，所描述的实施例仅仅是本申请一部份实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其它实施例，都属于本申请保护的范围。
请参考图1，其示出了本申请实施例提供的一种光源系统的局部结构示意图。如图1所示，目前的全三色光源系统通常包括两个二向色镜100、激光光源200、反射镜300、聚光透镜400、扩散轮500和光棒600。其中，激光光源200包括一个用于发出红色激光的红色激光器组件210、一个用于发出绿色激光的绿色激光器组件220和一个用于发出蓝色激光的蓝色激光器组件230，且激光器组件包括至少一个激光器。其中，红色激光器组件210发出的红色激光可以经过一个二向色镜110透射至聚光透镜400上。绿色激光器组件220发出的绿色激光可以先经过反射镜300反射至另一个二向色镜120上，然后经过该另一个二向色镜120反射至一个二向色镜110上，之后经过该一个二向色镜110反射至聚光透镜400上。蓝色激光器组件230发出的蓝色激光可以经过另一个二向色镜120透射至一个二向色镜110上，然后经过该一个二向色镜110反射至聚光透镜400上。照射至聚光透镜400上的激光经过该聚光透镜400汇聚后，照射至扩散轮500上。照射至扩散轮50上的激光经过扩散轮500的匀光后，照射至光棒600内，在该光棒600的匀光作用下，实现三色光源。
但是，全三色光源系统中激光光源包括的激光器种类和数量增多，不同颜色激光器的发光原理和性能也存在不同，随着三色光源的使用，激光器的发光亮度和构成的色彩色温方面会发生变化，导致激光投影设备的图像显示效果较差。
请参考图2，其示出了本申请实施例提供的一种激光投影设备的结构示意图。如图2所示，激光投影设备包括：
显示控制电路10，激光光源20和三组激光器驱动组件30，激光光源20包括颜色互不相同的三组激光器组件201，三组激光器组件201与三组激光器驱动组件30一一对应。
显示控制电路10分别与三组激光器驱动组件30连接，用于输出与多帧显示图像中的每一帧图像的三种基色一一对应的三个使能信号，将三个使能信号分别传输至对应的激光器驱动组件30。以及，输出与每一帧图像的三种基色一一对应的三个电流控制信号，将三个电流控制信号分别传输至对应的激光器驱动组件30，其中，每组激光器组件对应的电流控制信号在对应至少两帧显示图像时的大小不同。示例的，电流控制信号可以是脉冲宽度调制(PWM，Pulse Width Modulation)信号
每组激光器驱动组件30与对应的一组激光器组件201连接，用于向其所连接的激光器组件提供激光器组件对应的驱动电流，以及根据所述激光器组件的工作电流和发光亮度，调节对应的所述电流控制信号。
每组激光器组件201用于在对应的激光器驱动组件30的驱动下发光。
示例的，如图2所示，假设激光光源20包括红色激光器组件201a、绿色激光器组件100b和蓝色激光器组件100c。该显示控制电路01可以基于待显示图像的红色基色分量输出与红色激光器组件对应的红色PWM信号R_PWM，基于待显示图像的绿色基色分量输出与绿色激光器组件对应的绿色PWM信号G_PWM，基于待显示图像的蓝色基色分量输出与蓝色激光器组件对应的蓝色PWM信号B_PWM。并且，该显示控制电路01可以基于红色激光器组件在驱动周期内的点亮时长，输出与红色激光器组件对应的使能信号R_EN，基于绿色激光器组件在驱动周期内的点亮时长，输出与绿色激光器组件对应的使能信号G_EN，基于蓝色激光器组件在驱动周期内的点亮时长，输出与蓝色激光器组件 对应的使能信号B_EN。红色激光器组件100a、绿色激光器组件100b和蓝色激光器组件100c分别与对应的激光器驱动组件30连接。
综上所述，本申请实施例提供的激光投影设备，由于激光投影设备中显示控制电路可以基于待显示图像的三种基色分量输出三个电流控制信号，以及，输出三个使能信号，将三个使能信号和三个电流控制信号分别传输至对应的激光器驱动组件，使得每组激光器驱动组件可以向其所连接的激光器组件提供激光器组件对应的驱动电流。且由于每组激光器组件对应的电流控制信号在对应至少两帧待显示图像时的大小不同，因此，该激光投影设备可以支持可变亮度的激光器组件，有效提高激光投影设备的图像显示效果。并且，由于激光器驱动组件可以根据激光器组件的工作电流和发光亮度，调节对应的电流控制信号，实现了对激光器组件的发光亮度的反馈调节，避免了因激光器组件衰减导致的图像显示的白平衡变化，进而避免了因白平衡变化构成的色彩色温方面的变化，因此，更加有效地提高了激光投影设备的图像显示效果。
可选的，图3是本申请实施例提供的一种激光器驱动组件的结构示意图。如图3所示，激光器驱动组件30可以包括：驱动电路301和电流调节电路302。
驱动电路301分别与电流调节电路302和驱动输出端V outa连接，驱动输出端V outa用于连接激光器组件201，驱动电路301用于基于接收到的电流控制信号和使能信号，向驱动输出端V outa加载驱动电压。
电流调节电路302分别与驱动电路301和激光器组件201的电流通路中的检测节点连接，用于检测激光器组件201的工作电流，并根据激光器组件201当前的工作电流、激光器组件201的发光亮度和激光器组件201的初始亮度，调节电流控制信号。
图4是本申请实施例提供的一种激光器驱动组件的结构示意图。如图4所示，每个驱动电路301包括：驱动子电路3011、电压调节子电路3012、开关子电路3013和电流调节电路302。
驱动子电路3011分别与电压调节子电路3012、开关子电路3013和驱动输出端V outa连接，驱动子电路3011用于基于接收到的电流控制信号和电压调节子电路3012的电压输出端的输出电压向驱动输出端加载驱动电压，并将接收到的使能信号传输至开关子电路3013。
驱动子电路3011还用于根据输出电压向电压调节子电路3012输出控制信 号。
电压调节子电路3012，用于在控制信号的控制下，将输出电压调节为激光器组件201的额定电压。
开关子电路3013串联在激光器组件201的电流通路中，用于在接收到的使能信号为有效电位时，控制电流通路导通。
电流调节电路302分别与驱动子电路3011和激光器组件201的电流通路中的检测节点连接，用于检测激光器组件201的工作电流，并根据工作电流、激光器组件201的发光亮度和激光器组件201的初始亮度，调节电流控制信号。
示例的，电流调节电路302可以确定激光器组201的初始亮度与发光亮度的亮度差，根据该亮度差确定激光器组件201需要增加的电流值。进而可以根据该电流值调节电流控制信号。
可选的，图5是本申请实施例提供的一种电流调节电路的结构示意图。如图5所示，电流调节电路302包括：放大子电路3021和处理子电路3022。
放大子电路3021分别与激光器组件201的电流通路中的检测节点E和处理子电路3022连接，用于将检测到的激光器组件201的工作电流转换为工作电压，放大工作电压，并将放大后的工作电压传输至处理子电路3022。
处理子电路3022与驱动子电路3011连接，用于根据放大后的工作电压、激光器组件的发光亮度和激光器组件的初始亮度，输出电流控制信号。示例的，该处理子电路3022可以为微控制单元(Microcontroller Unit，MCU)，又称单片机。
示例的，如图5所示，放大子电路3021可以包括：第一运算放大器A1、第一电阻(又称取样功率电阻)R1、第二电阻R2、第三电阻R3和第四电阻R4。
第一运算放大器A1的同相输入端(又称正端)与第二电阻R2的一端连接，第一运算放大器A1的反相输入端(又称负端)分别与第三电阻R3的一端和第四电阻R4的一端连接，第一运算放大器A1的输出端分别与第四电阻R4的另一端和处理子电路3022连接。第一电阻R1的一端与检测节点E连接，第一电阻R1的另一端与参考电源端连接。第二电阻R2的另一端与检测节点E连接，第三电阻R3的另一端与参考电源端连接。
如图5所示，该第一运算放大器A1还可以包括两个电源端，其中一个电源端与电源端VCC1连接，另一个电源端可以与参考电源端连接。
作为一种可选的实现方式，如图4所示，在激光器组件201的电流通路中， 激光器组件201的正极可以与驱动输出端V outa连接，负极可以与开关子电路3013的输入端连接，开关子电路3013的输出端可以与该检测节点E连接。也即是，该第一电阻R1的一端可以与开关子电路3013的输出端连接。
作为另一种可选的实现方式，在激光器组件201的电流通路中，开关子电路3013的输入端可以与驱动输出端V outa连接，开关子电路3013的输出端可以与激光器组件201的正极连接。激光器组件201的负极可以与该检测节点E连接。也即是，该第一电阻R1的一端可以与激光器组件201的负极连接。
激光器组件201的较大的工作电流通过第一电阻R1后产生压降，该第一电阻R1一端(即检测节点E)的电压V i通过第二电阻R2传输至第一运算放大器A1的同相输入端，经过第一运算放大器A1放大N倍后输出。该N为该第一运算放大器A1的放大倍率，且N为正数。该放大倍率N可以使得第一运算放大器A1输出的电压V fb的数值为激光器组件的工作电流的数值的整数倍。示例的，电压V fb的数值可以与该工作电流的数值相等，从而便于处理子电路3022可以根据该放大后的工作电压确定激光器组件的工作电流。
本申请实施例中，该第一运算放大器A1的输入输出电压的放大公式为：
Figure PCTCN2020091012-appb-000001
V i为第一运算放大器A1的输入电压，V fb为第一运算放大器A1的输出电压。该第一运算放大器A1的放大倍数N满足：
Figure PCTCN2020091012-appb-000002
假设R1＝0.1Ω，激光器组件的工作电流为3A(安)，则V i＝3×R1＝0.3V。为了满足电压V fb的数值与该工作电流的数值相等，则电压V fb＝3V，相应的，N＝10，也即是
Figure PCTCN2020091012-appb-000003
即
Figure PCTCN2020091012-appb-000004
需要满足：
Figure PCTCN2020091012-appb-000005
当R4＝27kΩ时，R3＝3kΩ。
可选的，处理子电路3022还可以与设置在激光器组件周围的亮度传感器连接，该亮度传感器用于检测激光器组件的亮度，并将该亮度传输至该处理子电路3022。处理子电路3022可以在该激光器组件首次启动时，获取该亮度传感器检测的激光器组件亮度，并将该亮度作为初始亮度进行存储。在该激光器组件发光过程中，处理子电路3022可以实时或者周期性的获取该亮度传感器检测的激光器组件的发光亮度。
进一步的，处理子电路3022还可以具有数模转换功能，数模转换功能对应的管脚接收从放大子电路传输的电压V fb，处理子电路3022进而可以将电压V fb转换成激光器组件的工作电流。之后，处理子电路3022可以将该工作电流与该 需要增加的电流值叠加，基于叠加后的电流值输出电流控制信号，从而实现对电流控制信号的调节。
由于激光投影设备在使用的过程中，激光器组件出射的激光的亮度会随着时间而衰减，且由于不同颜色的激光器组件的发光原理的不同，不同颜色的激光器组件的发射的激光的亮度，其衰减程度不同，从而使得激光光源出射的激光的颜色发生改变，该激光的色温发生改变。其中，蓝色激光器组件的出射的激光的亮度的衰减程度小于红色激光器组件和绿色激光器组件的出射的激光的亮度的衰减程度。
因此，该电流调节电路302可以通过与驱动子电路3011、电压调节子电路3012和开关子电路3013形成闭环，以实现对该激光器组件的驱动电流的反馈调节，从而使得该电流调节电路可以通过激光器组件的发光亮度与初始亮度的差值，调节该激光器组件的工作电流(也即是调节该激光器组件的实际发光亮度)，对该激光器组件出射的激光的衰减亮度进行补偿，以更准确的控制激光器组件发光。
可选的，图6是本申请实施例提供的一种驱动子电路的结构示意图。如图6所示，驱动子电路3011包括：驱动芯片U和电流检测电阻R0。
驱动芯片U分别与电压调节子电路3012的电压输出端V outb、开关子电路3013、电流调节电路302和驱动输出端V outa连接。电流检测电阻R0的一端与该电压输出端V outb连接，电流检测电阻R0的另一端与驱动输出端V outa连接。
该驱动芯片U可以通过检测电流检测电阻R0上加载的电流，并将电流检测电阻R0上加载的电流调整至对应的激光器组件的驱动电流。请参考图6，该驱动电流I可以满足：
Figure PCTCN2020091012-appb-000006
值得说明的是，驱动芯片U可以通过多种方式确定激光器组件对应的驱动电流(即驱动电流的值)。在一种可选方式中，驱动芯片U在接收到电流控制信号后通过第一预设算法，计算激光器组件对应驱动电流的值。在另一种可选方式中，驱动芯片U预存有电流控制信号与电流的对应关系，驱动芯片U在接收到电流控制信号后，通过查询该对应关系即可得到相应的驱动电流。示例的，当电流控制信号为PWM信号时，该电流控制信号与电流的对应关系可以由PWM值与电流对应关系表征。请参考表1和图7，为了便于读者理解，表1示出了 PWM值、电流与亮度的对应关系表(实际应用中，驱动芯片U只需预存PWM值与电流对应关系)，图7是该对应关系表所对应的电流与亮度的关系曲线图。由图7可以看出，电流和亮度存在线性关系，通常电流越大，亮度越大，因此通过调节激光器组件的电流可以有效调节激光器组件的亮度。示例的，当接收到的PWM信号的PWM值为1023时，查询表1得到的驱动电流为2.6A，则将电流检测电阻R0上加载的电流调整为2.6A。最终激光器组件的亮度为2540lumen(流明)。
需要说明的是，在本申请实施例中，驱动芯片U接收的电流控制信号可以是上述显示控制电路10输出的，也可以是该激光器驱动组件30中电流调节电路302对电流控制信号进行调节后得到的。由于激光器组件衰减的过程较为缓慢，因此，通常以显示控制电路10提供电流控制信号为主，电流调节电路302提供的电流控制信号为辅助，也即是显示控制电路10和电流调节电路302可以交替向驱动芯片U提供电流控制信号。
可选的，显示控制电路10可以每间隔调节周期，停止向驱动芯片U提供电流控制信号，并由电流调节电路302向驱动芯片U提供电流控制信号。例如，显示控制电路10可以每间隔调节周期向电流调节电路302(例如，电流调节电路302的处理子电路3022)发送启动控制信号。该显示控制电路10发送该启动控制信号后，可以停止向驱动芯片U提供电流控制信号。电流调节电路302在接收到该启动控制信号后，可以向驱动芯片U提供电流控制信号。
其中，该调节周期可以为1个月、3个月或者1年等。显示控制电路10停止向驱动芯片U提供电流控制信号的时长(即电流调节电路302提供电流控制信号的时长)可以为1分钟、3分钟或者5分钟等。
表1
Figure PCTCN2020091012-appb-000007
Figure PCTCN2020091012-appb-000008
不同的应用场景中，前述电压输出电路302按工作模式的不同，可以分为升压电路，也可以为降压电路。升压电路是把输入电压VIN升高到激光器组件的额定电压Vo的电路，VIN＜Vo，降压电路是把输入电压VIN降低到激光器组件的额定电压Vo的电路，VIN＞Vo。由于升压电路的初始输入电压VIN相对于降压电路较低，若该升压电路出现短路等故障，该较低的初始输入电压Vi没有超出激光器组件的额定电压Vo，不会引起激光器组件的损伤，也不会引起人体的触电风险。因此，升压电路相对于降压电路对设备损伤的可能性较低，安全性较高。
可选的，电压调节子电路3012可以为升压子电路3012。该升压子电路3012还与输入电源端VIN连接，用于在控制信号的控制下，将输入电源端VIN提供的输入电压升压至额定电压Vo。
示例的，图8是本申请实施例提供的一种电压调节子电路的结构示意图。如图8所示，升压子电路3012可以包括：电感L、第一场效应管Q1、二极管D、电容C、第五电阻R5、第六电阻R6和第七电阻R7。
电感L的一端分别与驱动子电路3011和输入电源端VIN连接，电感L的另一端分别与第一场效应管Q1的第一极和二极管D的正极连接。第一场效应管Q1的栅极与驱动子电路3011连接，第一场效应管Q1的第二极分别与驱动子电路3011和第七电阻R7的一端连接。二极管D的负极分别与电容C的一端、第五电阻R5的一端以及电压调节子电路3012的电压输出端V outb连接。第五电阻R5的另一端分别与驱动子电路3011和第六电阻R6的一端连接。电容C的另一端、第六电阻R6的另一端以及第七电阻R7的另一端均与参考电源端连接。
在升压子电路3012中，通过将输入电源端VIN的电压升压至额定电压Vo，从电压调节子电路3012的电压输出端V outb输出。其中，也可以将输入电源端VIN的电压升压至(Vo+Vtb)，Vtb为指定阈值。
值得说明的是，在图8所示的升压子电路3012中，通过第五电阻R5和第六电阻R6之间的节点F，以及第五电阻R5和第六电阻R6的阻值，设定该升压子电路3012的额定电压Vo。其中，该额定电压Vo为：
Figure PCTCN2020091012-appb-000009
V b为节点F的参考电压，也即是驱动子电路3011中驱动芯片U的参考电压。由于驱动芯片U的参考电压V b和额定电压Vo通常为恒定值，因此，可以通过该参考电压V b和额定电压Vo确定第五电阻R5和第六电阻R6的阻值。
该图8所示的升压子电路3012的工作过程，可以分为充电过程和放点过程共两个。在该两个工作过程中，该升压电路的工作原理如下：
充电过程：第一场效应管Q1开启，输入电源端VIN持续给电感L储能，电感L上的电流线性增加，同时，二极管D反向截止，阻止电容C的电压对参考电源端O放电(当参考电源端O为参考地时，即对地放电)，因此直流电不断给电感L充电储能，形成电流回路h1。
放电过程：第一场效应管Q1关断，相当于上述电流回路h1断路，由于电感L的电流不能发生突变，流经电感L的电流缓慢放电直到为0。由于电流回路h1电路已断开，电感L只能通过二极管D给电容C充电，使电容C的电动势不断升高，形成电流回路h2。
通过该升压子电路3012的电压输出端V outb的电压与额定压电Vo的大小，控制第一场效应管Q1的栅极，使得第一场效应管Q1以一定频率不断开启和关 断，控制升压电路203不断进行充放电，使电容C两端的电压不断升高直到达到设置的额定电压Vo，从而完成升压电路的升压。
由于在第五电阻R5和第六电阻R6的阻值一定时，节点F的电压可以反映升压电路203的电压输出端V outb输出的电压。因此，可以通过比较节点F的实际电压与该节点F的参考电压的大小，控制第一场效应管Q1的栅极，使得第一场效应管Q1以一定频率不断开启和关断。
示例的，该第一场效应管Q1可以为N型金属氧化物半导体(N‐Metal‐Oxide‐Semiconductor，NMOS)管。当节点F的实际电压小于该节点F的参考电压时，可以控制栅极输入的电平信号相对于源极的电平信号为高电平，NMOS管开启。当节点F的实际电压大于或等于该节点F的参考电压时，可以控制栅极输入的电平信号相对于源极的电平信号为低电平，NMOS管关断。
值得说明的是，前述对第一场效应管Q1开启和关断的控制，和/或，对第五电阻R5和第六电阻R6之间的节点F的参考电压V b的设置可以采用单独的控制芯片或控制电路进行控制，也可以由驱动芯片进行控制。图8假设由驱动芯片U控制第一场效应管Q1的开启和关断，以及，设置第五电阻R5和第六电阻R6之间的节点F的参考电压V b。
示例的，驱动芯片U可以以100kHz(千赫兹)以上的频率对第一场效应管Q1进行开启和关断控制，也即是开关频率大于或等于100kHz。这种开关频率可以最大限度地缩减分立元件，如电感、二极管等的尺寸，并保持了的较高的驱动效率，使所产生的分立元件温升较小，热量更容易控制，避免驱动电路过热。
可选的，图9是本申请实施例提供的一种激光器驱动组件的局部结构示意图。如图9所示，开关子电路3013包括：第二场效应管Q2。第二开关场效应管Q2的栅极与驱动子电路3011连接，第二场效应管Q2的第一极和第二极分别与激光器组件201的电流通路中的两个节点连接。
示例的，第二场效应管Q2的栅极与驱动子电路3011中驱动芯片U连接，第二场效应管Q2的第一极可以与激光器组件201的一端(例如负极)连接，第二场效应管Q2的第二极可以与第一电阻R1的一端连接。其中，该第二场效应管Q2的第一极可以为该开关子电路3013的输入端，该第二场效应管Q2的第二极可以为该开关子电路3013的输出端。
或者，第二场效应管Q2的栅极与驱动子电路3011中驱动芯片U连接，第 二场效应管Q2的第一极可以与激光器组件201的另一端(例如正极)连接，第二场效应管Q2的第二极可以驱动输出端V outa连接。
当驱动芯片U接收到的使能信号为有效电位时，控制第二场效应管Q2的栅极输入的电平信号相对于源极的电平信号为高电平，第二场效应管Q2开启，激光器组件201的电流通路导通，形成电流回路h3，该激光器组件201点亮。当驱动芯片U接收到的使能信号为无效电位时，控制第二场效应管Q2的栅极输入的电平信号相对于源极的电平信号为低电平，第二场效应管Q2关断，激光器组件201的电流通路截止，该激光器组件201熄灭。
示例的，以红色激光器组件对应的激光器驱动组件为例进行说明。假设每一帧图像的驱动周期为T，高电平为有效电位，红色激光器组件在一个驱动周期T内的导通时长(即点亮时长)为t，则红色激光器组件对应的使能信号EN_R在一个驱动周期T内的高电平时长为t，该使能信号EN_R输入到驱动芯片U后，控制开关子电路3013的开启和关断，以此来实现对红色激光器组件的点亮和熄灭的控制。
在该一个驱动周期T内，当该使能信号EN_R为高电平时，第二场效应管Q2开启，红色激光器组件的电流通路导通，红色激光器组件的点亮时长为t。当该使能信号EN_R为低电平时，第二场效应管Q2关断，红色激光器组件的电流通路不导通，红色激光器组件不工作，则红色激光器组件熄灭的时长为T‐t。
需要说明是，图9中假设激光器组件201包括串联的n个激光器，分别为激光器LD 1至LDn。该激光器LD 1至LDn不属于开关子电路3013。
可选的，该第二场效应管Q2可以为N型金属氧化物半导体(N‐Metal‐Oxide‐Semiconductor，NMOS)管，该第二场效应管Q2的他通断时间可以达到ns(纳秒)级。这样使得该激光器驱动组件向激光器组件的通断电流的响应速度较快，且精度较高，降低了因激光器组件开关延迟造成光的混色现象的概率，提供了激光电视显示效果，为实时根据待显示图像调整向激光器组件加载的驱动电压，也即是调整激光器
Figure PCTCN2020091012-appb-000010
的驱动电流提供了硬件基础。
本申请实施例中，如前所述，电流控制信号可以为PWM信号，PWM信号在传输过程中会产生一定的衰减，衰减导致PWM信号的幅值(也称高电平幅值)低于有效设置的满量程幅值。本申请实施例提供一种电压跟随器，可以不改变PWM信号的占空比，将接收到的幅值低于满量程幅值的PWM信号，调整为幅 值为满量程幅值的PWM信号，这样避免信号传输所导致的信号衰减，保证输入驱动芯片的电流控制信号的准确性，提高后续驱动精度。
可选的，如图4所示，激光器驱动组件30还包括：电压跟随器(又称中继其)3014，电压跟随器3014与驱动子电路3011连接，用于对接收到的与激光器组件201对应的电流控制信号进行处理，并将处理后的电流控制信号输出至驱动子电路3011。
图10是本申请实施例提供的一种电压跟随器的结构示意图。如图10所示，电压跟随器3014包括：第二运算放大器A2、第八电阻R8、第九电阻R9、第十电阻R10和第十一电阻R11。
第二运算放大器A2的同相输入端与第八电阻R8的一端连接，第二运算放大器A2的反相输入端与第九电阻R9的一端连接，第二运算放大器A2的输出端分别与第九电阻R9的另一端和第十电阻R10的一端连接。第八电阻R8的另一端用于接收电流控制信号。第十电阻R10的另一端分别与驱动子电路3011和第十一电阻R11的一端连接。第十一电阻R11的另一端与参考电源端连接。其中，第八电阻R8和第九电阻R9的阻值相同。该第二运算放大器A2还可以包括两个电源端，其中一个电源端与电源端VCC2连接，另一个电源端与参考电源端连接。
本申请实施例在实际实现时，由于该电压跟随器和驱动芯片的额定电压可能不同，因此，第十电阻R10和第十一电阻R11可以为分压电阻，以使得电压跟随器输出的电压可以匹配驱动芯片对应管脚的输入电压要求，保证激光器驱动组件的正常工作。示例的，第十电阻R10和第十一电阻R11之间的节点G用于输出分压处理后的电流控制信号，该节点G输出的电压为驱动芯片的额定电压。第十电阻R10和第十一电阻R11的阻值根据电压跟随器和驱动芯片的额定电压设置。
如图11所示，由于第八电阻R8与第九电阻R9的阻值相等，PWM信号经过第二运算放大器A2之后，不会改变PWM信号的占空比，但会使PWM信号幅值由低于幅值电压VCC调整为等于幅值电压VCC，也即是满量程，因此可以保证处理后的电流控制信号相对于初始输出的电流控制信号无衰减。
并且，由于电压跟随器具有输入阻抗高，输出阻抗低的特点。在一定程度上可以避免由于输出阻抗较高，而下一级输入阻抗较小时产生的信号损耗，起到承上启下的作用，也即是缓冲作用。由于电压跟随器具有输入阻抗高，输出 阻抗低的特点，使得它对上一级电路呈现高阻状态，而对下一级电路呈现低阻状态，常用于中间级，以隔离前后级电路，消除它们之间的相互影响。在本申请实施例中，电压跟随器可以隔离驱动芯片前端的电路(例如显示控制电路)产生的各种噪声，因此可以提高激光器驱动组件的精度。
请参考图12，其示出了本申请实施例提供的一种激光器驱动组件的结构示意图。如图12所示，驱动子电路3011中驱动芯片U包括：第一引脚EN、第二引脚CTRL、第三引脚ISN、第四引脚ISP、第五引脚V IN、第六引脚FB、第七引脚GATE、第八引脚SENSE、第九引脚ENOUT。
其中，第一引脚EN与显示控制电路连接，用于接收显示控制电路传输的使能信号。第二引脚CTRL通过电压跟随器3014分别与显示控制电路和电流调节电路302连接，用于接收电流控制信号。示例的，第二引脚CTRL与电压跟随器3014中第十电阻的另一端连接，该电压跟随器3014中第八电阻R8的另一端分别与显示控制电路和电流调节电路302中处理子电路连接。
第三引脚ISN与驱动输出端V outa，第四引脚ISP与电压调节子电路3012的电压输出端V outb。第五引脚V IN与输入电源端VIN连接，用于为驱动芯片U提供电源。第六引脚FB与电压调节子电路3012中节点F连接。第七引脚GATE与电压调节子电路3012中第一场效应管Q1的栅极连接。第八引脚SENSE分别与电压调节子电路3012中第七电阻的一端和第一场效应管Q1的第二极连接。该第八引脚SENSE用于通过检测第一场效应管Q1的第二极和第七电阻之间的电压来采集升压电路的电流，当采集的电流大于设定的电流上限阈值时，驱动芯片U会控制第七引脚GATE关断此升压电路的电流回路。从而基于采集的电流来实现升压电路的过电流保护。第九引脚ENOUT与第二场效应管Q2的栅极连接。
需要说明的是，驱动芯片U的工作原理可以参考前述实施例中的相关描述，本实施例对此不再赘述。
还需要说明的是，在本申请实施例中，参考电源端可以为接地端。
综上所述，本申请实施例提供的激光投影设备，由于激光投影设备中显示控制电路可以基于待显示图像的三种基色分量输出三个电流控制信号，以及，输出三个使能信号，将三个使能信号和三个电流控制信号分别传输至对应的激光器驱动组件，使得每个所述激光器驱动组件可以向其所连接的激光器组件提供激光器组件对应的驱动电流。且由于每个所述激光器组件对应的电流控制信 号在对应至少两帧待显示图像时的大小不同，因此，该激光投影设备可以支持可变亮度的激光器组件，有效提高激光投影设备的图像显示效果。并且，由于激光器驱动组件可以根据激光器组件的工作电流和发光亮度，调节对应的电流控制信号，实现了对激光器组件的发光亮度的反馈调节，避免了因激光器组件衰减导致的图像显示的白平衡变化，进而避免了因白平衡变化构成的色彩色温方面的变化，因此，更加有效地提高了激光投影设备的图像显示效果。
随着社会的发展，人们对激光投影设备的图像显示效果要求越来越高，因此也对影响显示效果的一系列参数(例如，对比度)有了更高的要求。其中，激光投影设备的对比度通常分为静态对比度和动态对比度。静态对比度通常指的是采用美国国家标准学会(American national standards institute，ANSI)制定的对比度算法计算得到对比度，其指的是一张图片(即同一帧图像)中白色区域的亮度与黑色区域的亮度比。
动态对比度指的是同一帧图像在显示过程中的明暗比，其与显示过程中激光光源的亮度相关，也即是该一帧图像在显示过程中最亮的白色区域与最暗的黑色区域的亮度比。例如公式(1)所示，动态对比度C满足：
Figure PCTCN2020091012-appb-000011
L w为该一帧图像在显示过程中最亮的白色区域的亮度，L B为该一帧图像在显示过程中最暗的黑色区域的亮度。
通过上述动态对比度的公式可知，当L w达到最大值时，可以通过降低L B的值，提高动态对比度。其中，激光投影设备的图像的实际显示亮度通常由两个因素决定，一个因素是激光光源的亮度，另一个因素是图像的灰阶值(也即是图像自身的亮度)，该两个因素的叠加最终可以确定一帧图像的实际显示亮度，因此，可以通过调节该两个因素的比例来优化显示效果。
通常情况下，激光投影设备所显示的视频中图像自身的亮度是基于其内容不断变化的，对于每一帧图像，均可以根据图像自身的亮度调整激光光源，从而调整图像的实际显示亮度。例如，当一帧图像为黑色画面时，可以通过降低激光光源的亮度，使得该一帧图像的实际显示亮度相较于其自身亮度更低。这样，可以通过降低激光光源的亮度，降低激光投影设备在显示图像时的实际显 示亮度的下限值，即最低实际显示亮度(L B)，提高该激光投影设备在显示图像时的动态对比度。同时由于降低了激光光源的亮度，因此，也降低了该激光投影设备的功耗。
本申请实施例提供的激光投影设备，可以在不改变图像的实际显示亮度，从而提高该激光投影设备的动态对比度。其图像显示的原理为：对激光光源的亮度和待显示图像的灰阶值分别进行处理，以增强图像的细节表达，进而在保证显示图像的亮度不变的前提下，降低光源亮度，提高激光投影设备的动态对比度。为了便于读者理解，本申请实施例以图13至图15为例对本申请实施例所涉及的图像显示原理进行说明：
如图13至图15所述，图13至图15示出了输入信号灰阶值(也称显示灰阶值或图像自身亮度)与屏幕亮度(也即是实际显示亮度)的关系。图13至图15中，横坐标为输入信号灰阶值，纵坐标为屏幕亮度。假设激光投影设备所能处理的图像的最大灰阶值为256，激光光源的功率(由于激光光源的功率与激光光源的亮度成正比，本申请实施例中，假设激光光源的功率等价于激光光源的亮度)为一个标准量(也即是参考量)，例如为单位以一，则，如图13所示，该激光投影设备的输入信号灰阶值与屏幕亮度的曲线(也即是伽马曲线)为图13中的实线。假设，当前显示的一帧图像A的输入信号灰阶值为160，则对应的屏幕亮度为96，如图14所示，将该帧图像A的输入的信号灰阶值增益D倍，该帧图像A转化为图像A’，该图像A’对应的屏幕亮度为192。如图15所示，可以通过降低激光光源的功率使屏幕亮度降为96，从而将图像A’转化为图像A。这样，由于图像的显示灰阶值范围越大，图像的细节表达越丰富，而本申请实施例提供的激光投影设备可以将图像的显示灰阶值的范围扩大，也即是提高了显示灰阶值的上限值，因此，增强了图像的细节表达，同时，在保证图像A的实际显示亮度不变的前提下，激光光源的亮度降低，对比度提高，功耗降低。
可选的，如图16所示，激光投影设备还包括：光调制器件40，该光调制器件40可以为数字微镜器件(Digital Micro mirror Device，DMD)或者液晶覆硅(Liquid Crystal on Silicon，LCOS)。
进一步的，显示控制电路10包括：算法处理器101和控制处理模块102，算法处理器101与控制处理模块102连接，控制处理模块102还分别与激光器驱动组件30以及光调制器件40连接。该算法处理器101可以采用现场可编程 门阵列(Field－Programmable Gate Array，FPGA)来实现。
算法处理器101，用于根据多帧显示图像中的每一帧图像的图像显示数据(例如灰阶值)，确定每一帧图像的增益值α，α≥1。其中，每一帧图像的图像显示数据可以反映出每一帧图像颜色的基本分布和基本色调，当图像显示数据为4K数据时，该4K数据可以以V‐by‐One(一种面向图像传输开发出的数字接口标准)信号的方式输入至算法处理器101。
算法处理器101，还用于向控制处理模块102发送该图像显示数据，以及与激光器组件对应的电流控制信号。
其中，前述每个电流控制信号用于指示对应的激光器组件的调整后的亮度，调整后的亮度为调整前的亮度的1/α，图像显示数据用于指示调整后的每一帧图像的灰阶值，调整后的灰阶值为调整前的灰阶值的α倍。
控制处理模块102用于向光调制器件40发送图像显示数据，以及与激光器组件对应的电流控制信号。
光调制器件40，用于基于图像显示数据，对激光光源的光束进行调制，以输出影像光束，并将该影像光束投影至显示屏上，实现每一帧图像的显示。
需要说明的是，激光投影设备还可以包括：多个光学透镜，该多个光学透镜位于光调制器件40与显示屏之间，该多个光学透镜用于对影像光束进行透射、反射和/或者折射后，投影至显示屏上。
在本申请实施例中，显示控制电路10可以基于每一帧图像的增益值α，也即是每一帧图像的变化，实时地调节激光光源的亮度，从而实现动态对比度。并且由于激光器驱动组件的光源开关电路中，当第一开关晶体管为MOS管，例如NMOS管时，光源开关电路的通断时间达到ns(纳秒)级，激光器驱动组件的通断时间达到μs(微秒)级，从而使激光器组件的电流响应速度快，精度高，也即是该激光器驱动组件可以快速，高精度地响应图像各个像素亮度的变化，且可以实现激光器组件的亮度从0到额定电流值所对应亮度的之间任意调节，减少了多种基色光由于激光器驱动组件反应速度慢导致的混色严重的画质问题，此驱动电路是实现高动态对比度的基础，即在硬件上支持了激光投影设备的动态亮度调节。
随着激光投影设备分辨率的提高，激光投影设备的图像显示数据越来越大， 例如该图像显示数据为4K数据，即像素分辨率为4096×2160的数据，显示控制电路10只采用一个处理器容易引起处理器处理效率较低，因此，本申请实施例提出主从处理器协同处理图像显示数据的方式，以提高处理效率。
如图17所示，控制处理模块102可以包括：主控处理器1021和从控处理器1022，算法处理器101分别与主控处理器1021和从控处理器1022连接。主控处理器1021还分别与激光器驱动组件30以及光调制器件40连接，从控处理器1022还与光调制器件40连接。
算法处理器101，用于根据每一帧图像的灰阶值，确定每一帧图像的增益值α，α≥1。
算法处理器101，还用于向主控处理器1021发送电流控制信号和第一子数据，并向从控处理器发送第二子数据。该第一子数据和第二子数据组成上述图像显示数据。
示例的，当该图像显示数据为4K数据时，第一子数据和第二子数据均为60bit(比特)数据，且第一子数据和第二子数据均可以为低电压差分信号(Low‐Voltage Differential Signaling，LVDS)，其中，第一子数据为两路west(西)LVDS，第二子数据可以为两路east(东)LVDS。
可选的，算法处理器101可以通过多种方式输出电流控制信号。本申请实施例以下两种为例进行说明。
在一种可选方式中，算法处理器101确定了每一帧图像的增益值α后，计算得到每组激光器组件的亮度，并通过第二预设算法基于该亮度输出电流控制信号。
在另一种可选方式中，算法处理器101可以预存有电流控制信号与亮度的对应关系，在确定了每一帧图像的增益值α后，算法处理器101计算得到每组激光器组件的亮度，然后根据计算得到的亮度查询该对应关系，得到与激光器组件相应的电流控制信号。
示例的，当电流控制信号为PWM信号时，该电流控制信号与电流的对应关系可以由PWM值与亮度的对应关系表征。该对应关系可以参考上述表1中PWM值与亮度的对应关系。
主控处理器1021，用于向激光器驱动组件30发送电流控制信号和使能信号，并向光调制器件40发送第一子数据。
从控处理器1022，用于向光调制器件40发送第二子数据。
光调制器件40，用于基于第一子数据和第二子数据，对激光光源的光束进行调制，以输出影像光束，并将该影像光束投影至显示屏上，实现每一帧图像的显示。
进一步的，如图18所示，该激光投影设备还包括：存储器50，振镜驱动电路60，振镜70和电源模块80。
其中，存储器50与算法处理器101连接，用于存储图像显示数据。请参考图16和图17，即存储调整后的每一帧图像的灰阶值，例如，该存储器为双倍速率(Double Data Rate，DDR)存储器。
振镜驱动电路60分别与算法处理器101以及振镜70连接，用于在算法处理器101的控制下带动振镜70振动。示例的，该振镜70可以为4维振镜，也即是能够在4个方向上振动，通过设置该振镜驱动电路60以及振镜70，可以进行图像叠加显示，增加细节表现力，相当于分辨率提升。
电源模块80用于为用电元件提供电能，其与激光投影设备中的各个用电元件分别连接，图18仅以其与主控处理器1021连接进行示意图说明。
值得说明的是，该激光投影设备还可以包括：两个二向色镜200、反射镜300、聚光透镜400、扩散轮500和光棒600等，各个元件的功能可以参考图1，本申请实施例对此不再赘述。
本领域技术人员在考虑说明书及实践这里公开的申请后，将容易想到本申请的其它实施方案。本申请旨在涵盖本申请的任何变型、用途或者适应性变化，这些变型、用途或者适应性变化遵循本申请的一般性原理并包括本申请未公开的本技术领域中的公知常识或惯用技术手段。说明书和实施例仅被视为示例性的，本申请的真正范围和精神由权利要求指出。
应当理解的是，本申请并不局限于上面已经描述并在附图中示出的精确结构，并且可以在不脱离其范围进行各种修改和改变。本申请的范围仅由所附的权利要求来限制。

Claims (10)

  1. 一种激光投影设备，其特征在于，所述激光投影设备包括：显示控制电路，激光光源和三组激光器驱动组件，所述激光光源包括颜色互不相同的三组激光器组件，三组所述激光器组件与所述三组激光器驱动组件一一对应；
    所述显示控制电路分别与每个所述激光器驱动组件连接，用于输出与多帧显示图像中的每一帧图像的三种基色一一对应的三个使能信号，将三个所述使能信号分别传输至对应的所述激光器驱动组件，以及，输出与所述每一帧图像的三种基色一一对应的三个电流控制信号，将三个所述电流控制信号分别传输至对应的所述激光器驱动组件；
    每个所述激光器驱动组件与对应的一个所述激光器组件连接，用于向其所连接的所述激光器组件提供所述激光器组件对应的驱动电流，以及根据所述激光器组件当前的工作电流和发光亮度，调节对应的所述电流控制信号；
    每个所述激光器组件用于在对应的激光器驱动组件的驱动下发光。
  2. 根据权利要求1所述的激光投影设备，其特征在于，所述激光器驱动组件包括：驱动电路和电流调节电路；
    所述驱动电路分别与电流调节电路和驱动输出端连接，所述驱动输出端用于连接所述激光器组件，所述驱动电路用于基于接收到的所述电流控制信号和所述使能信号，向所述驱动输出端加载驱动电压；
    所述电流调节电路分别与驱动电路和所述激光器组件的电流通路中的检测节点连接，用于检测所述激光器组件的工作电流，并根据所述工作电流、所述激光器组件的发光亮度和所述激光器组件的初始亮度，调节所述电流控制信号。
  3. 根据权利要求2所述的激光投影设备，其特征在于，所述电流调节电路包括：放大子电路和处理子电路；
    所述放大子电路分别与所述检测节点和所述处理子电路连接，用于将检测到的所述激光器组件的工作电流转换为工作电压，放大所述工作电压，并将放大后的工作电压传输至所述处理子电路；
    所述处理子电路与所述驱动电路连接，用于根据所述放大后的工作电压、所述激光器组件的发光亮度和所述激光器组件的初始亮度，输出所述电流控制信号。
  4. 根据权利要求3所述的激光投影设备，其特征在于，所述放大子电路包括：第一运算放大器、第一电阻、第二电阻、第三电阻和第四电阻；
    所述第一运算放大器的同相输入端与所述第二电阻的一端连接，所述第一运算放大器的反相输入端分别与所述第三电阻的一端和所述第四电阻的一端连接，所述第一运算放大器的输出端分别与所述第四电阻的另一端和所述处理子电路连接；
    所述第一电阻的一端与所述检测节点连接，所述第一电阻的另一端与参考电源端连接；
    所述第二电阻的另一端与所述检测节点连接，所述第三电阻的另一端与参考电源端连接。
  5. 根据权利要求2所述的激光投影设备，其特征在于，所述驱动电路包括：驱动子电路、电压调节子电路和开关子电路；
    所述驱动子电路分别与所述电压调节子电路、所述开关子电路和所述驱动输出端连接，所述驱动子电路用于基于接收到的所述电流控制信号和所述电压调节子电路的电压输出端的输出电压向所述驱动输出端加载驱动电压，并将接收到的所述使能信号传输至所述开关子电路；
    所述驱动子电路还用于根据所述输出电压向所述电压调节子电路输出控制信号；所述电压调节子电路，用于在所述控制信号的控制下，将所述输出电压调节为所述激光器组件的额定电压；
    所述开关子电路串联在所述激光器组件的电流通路中，用于在接收到的使能信号为有效电位时，控制所述电流通路导通。
  6. 根据权利要求5所述的激光投影设备，其特征在于，所述电压调节子电路为升压子电路；
    所述升压子电路还与输入电源端连接，用于在所述控制信号的控制下，将所述输入电源端提供的输入电压升压至所述额定电压。
  7. 根据权利要求6所述的激光投影设备，其特征在于，所述升压子电路包括：电感、第一场效应管、二极管、电容、第五电阻、第六电阻和第七电阻；
    所述电感的一端分别与所述驱动子电路和所述输入电源端连接，所述电感的另一端分别与所述第一场效应管的第一极和所述二极管的正极连接；
    所述第一场效应管的栅极与所述驱动子电路连接，所述第一场效应管的第二极分别与所述驱动子电路和所述第七电阻的一端连接；
    所述二极管的负极分别与所述电容的一端、所述第五电阻的一端以及所述电压 输出端连接；
    所述第五电阻的另一端分别与所述驱动子电路和所述第六电阻的一端连接；
    所述电容的另一端、所述第六电阻的另一端以及所述第七电阻的另一端均与所述参考电源端连接。
  8. 根据权利要求5至7任一所述的激光投影设备，其特征在于，所述驱动子电路包括：驱动芯片和电流检测电阻；
    所述驱动芯片分别与所述电压调节子电路的电压输出端、所述开关子电路、所述电流调节电路和所述驱动输出端连接；
    所述电流检测电阻的一端与所述电压输出端连接，所述电流检测电阻的另一端与所述驱动输出端连接。
  9. 根据权利要求5至7任一所述的激光投影设备，其特征在于，所述开关子电路包括：第二场效应管；
    所述第二开关场效应管的栅极与所述驱动子电路连接，所述第二场效应管的第一极和第二极分别与所述电流通路中的两个节点连接。
  10. 根据权利要求2至7任一所述的激光投影设备，其特征在于，所述电流控制信号为PWM信号，所述激光器驱动组件还包括：
    电压跟随器，所述电压跟随器与所述驱动电路连接，用于对接收到的与所述激光器组件对应的电流控制信号进行处理，并将处理后的电流控制信号输出至所述驱动电路。
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