CN112114479A

CN112114479A - Laser projection device

Info

Publication number: CN112114479A
Application number: CN201910538290.8A
Authority: CN
Inventors: 崔荣荣; 郭大勃
Original assignee: Qingdao Hisense Laser Display Co Ltd
Current assignee: Qingdao Hisense Laser Display Co Ltd
Priority date: 2019-06-20
Filing date: 2019-06-20
Publication date: 2020-12-22
Anticipated expiration: 2039-06-20
Also published as: CN113848677A; CN113835287A; WO2020252888A1; CN113835287B; CN112114479B; CN113848677B

Abstract

The invention relates to laser projection equipment, and belongs to the field of projection display. The method comprises the following steps: the display control circuit, the laser light source, a plurality of laser drive circuits, the laser light source includes the laser assembly of three primary colors; the display control circuit is used for generating a plurality of enabling signals which are in one-to-one correspondence with three primary colors of each frame of image in a plurality of frames of display images, respectively transmitting the plurality of enabling signals to the corresponding laser driving circuits, generating a plurality of current control signals which are in one-to-one correspondence with the three primary colors of each frame of image, and respectively transmitting the plurality of current control signals to the corresponding laser driving circuits; each laser driving circuit is used for providing driving current corresponding to the laser component for the laser component connected with the laser driving circuit, wherein the current control signals corresponding to each laser component are different in size when corresponding to at least two frames of display images; the laser components are used for emitting light under the drive of the corresponding laser drive circuits. The invention improves the image display effect.

Description

Laser projection device

Technical Field

The invention belongs to the field of projection display, and particularly relates to laser projection equipment.

Background

Laser televisions such as ultra-short-focus laser televisions are widely used in the display field because of their advantages of high color purity, large color gamut, high brightness, and the like.

The light source system of the current laser television generally includes a laser light source, which is generally a blue laser for emitting blue laser light, a fluorescent wheel, and a color filter wheel. The blue laser irradiates three different areas of the fluorescent wheel in time sequence to generate three colors of light, and the three colors of light are filtered by the color filter wheel in sequence to obtain three colors of light with higher purity. However, since the light source system irradiates blue laser to the fluorescent wheel to generate three-color light, the control requirement for the fluorescent wheel is increased, and the color effect of the three-color light generated by the fluorescent wheel is poor. Therefore, an all three-color light source system has been developed, in which a laser light source includes three color lasers so as to directly generate three color lights.

However, due to the increase of the number of lasers included in the laser light source in the all three-color light source system, the lasers of each color need to be controlled separately, and the lasers of each color can only provide laser light with fixed brightness, so the display effect of the final laser projection device is poor.

Disclosure of Invention

The invention provides laser projection equipment, which can solve the problem of poor display effect of the laser projection equipment, and adopts the following technical scheme:

in a first aspect, a laser projection apparatus is provided, which includes:

the laser driving circuit comprises a display control circuit, a laser light source and a plurality of laser driving circuits, wherein the laser light source comprises laser components with three primary colors, the laser components correspond to the laser driving circuits one by one, and the laser components comprise at least one laser;

the display control circuit is used for generating a plurality of enable signals which are in one-to-one correspondence with three primary colors of each frame of image in a plurality of frames of display images, respectively transmitting the enable signals to the corresponding laser driving circuits, generating a plurality of current control signals which are in one-to-one correspondence with the three primary colors of each frame of image, and respectively transmitting the current control signals to the corresponding laser driving circuits;

each laser driving circuit is used for providing driving current corresponding to the laser component for the laser component connected with the laser driving circuit, wherein the current control signal corresponding to each laser component has different sizes when corresponding to at least two frames of display images;

the laser assembly is used for emitting light under the drive of the corresponding laser drive circuit.

The technical scheme provided by the invention can have the following beneficial effects:

according to the laser projection equipment provided by the invention, the display control circuit in the laser projection equipment can generate a plurality of enabling signals which are in one-to-one correspondence with the three primary colors of each frame image in a plurality of frames of display images, the plurality of enabling signals are respectively transmitted to the corresponding laser driving circuits, a plurality of current control signals which are in one-to-one correspondence with the three primary colors of each frame image are generated, the plurality of current control signals are respectively transmitted to the corresponding laser driving circuits, and each laser driving circuit can provide the driving current corresponding to the laser component for the laser component connected with the laser driving circuit. Because the current control signals corresponding to each laser component have different sizes when corresponding to at least two frames of display images, the laser projection equipment can support the laser components with variable brightness, and the display effect of the laser projection equipment is effectively improved.

And because the laser projection equipment expands the range of the gray-scale value of each frame of image according to the gain value and reduces the brightness of the laser light source, the detailed expression of the image is enhanced, and the contrast of the image is improved, namely the contrast of the laser projection equipment when the image is displayed is improved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

Drawings

In order to illustrate the embodiments of the present invention more clearly, the drawings that are needed in the description of the embodiments will be briefly described below, it being apparent that the drawings in the following description are only some embodiments of the invention, and that other drawings may be derived from those drawings by a person skilled in the art without inventive effort.

Fig. 1 is a schematic partial structural diagram of a light source system according to an embodiment of the present invention;

FIG. 2 is a block diagram of a laser projection device provided by an embodiment of the invention;

fig. 3 is a schematic structural diagram of a laser driving circuit according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a partial structure of a laser driving circuit according to an embodiment of the present invention;

FIG. 5 is a graph of current versus brightness according to an embodiment of the present invention;

fig. 6 is a schematic diagram of a partial structure of a laser driving circuit according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a repeater according to an embodiment of the present invention;

fig. 8 is a schematic waveform diagram of a PWM signal before and after being processed by a repeater according to an embodiment of the present invention;

fig. 9 is a schematic diagram of a partial structure of a voltage boosting circuit according to an embodiment of the present invention;

fig. 10 is a schematic diagram of a partial structure of a laser driving circuit according to an embodiment of the present invention;

fig. 11 is a schematic structural diagram of a laser driving circuit according to an embodiment of the present invention;

FIG. 12 is a graph showing the relationship between the gray level of an input signal and the screen brightness according to an embodiment of the present invention;

FIG. 13 is a graph showing the relationship between the gray level of an input signal and the screen brightness according to an embodiment of the present invention;

FIG. 14 is a graph of gray level of an input signal versus screen brightness according to an embodiment of the present invention;

FIG. 15 is a block diagram of a laser projection device provided by an embodiment of the invention;

FIG. 16 is a block diagram of a laser projection device provided by an embodiment of the invention;

fig. 17 is a block diagram of a laser projection apparatus according to an embodiment of the present invention.

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

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, a partial structural schematic diagram of a light source system according to an embodiment of the invention is shown. As shown in fig. 1, the all-three-color light source system generally includes a laser light source 10, two dichroic mirrors 20, a reflecting mirror 30, a condensing lens 40, a diffusion wheel 50, and a light rod 60. The laser light source 10 includes a red laser assembly 101 for emitting red laser light, a green laser assembly 102 for emitting green laser light, and a blue laser assembly 103 for emitting blue laser light. The red laser light emitted from the red laser assembly 101 may be transmitted to the condensing lens 40 through a dichroic mirror 201. The green laser light emitted from the green laser assembly 102 may be reflected to another dichroic mirror 202 through the reflecting mirror 30, then reflected to one dichroic mirror 201 through the another dichroic mirror 202, and then reflected to the condensing lens 40 through the one dichroic mirror 201. The blue laser light emitted from the blue laser module 103 may be transmitted to one dichroic mirror 201 through another dichroic mirror 202, and then reflected to the condenser lens 40 through the one dichroic mirror 201. The laser light applied to the condensing lens 40 is condensed by the condensing lens 40 and then applied to the diffusion wheel 50. The laser irradiated on the diffusion wheel 50 is irradiated into the light bar 60 after being homogenized by the diffusion wheel 50, and a three-color light source is realized under the action of the homogenized light of the light bar 60. Wherein the laser assembly comprises at least one laser.

Since the lasers of each color (i.e., the laser assemblies) in the all-three-color light source system need to be controlled separately, and the lasers of each color can only provide laser light with a fixed brightness, the display effect of the final laser projection device is poor.

An embodiment of the present invention provides a laser projection apparatus, which may be a laser television, for example, as shown in fig. 2, and includes:

the display control circuit 70, the laser light source 10, a plurality of laser drive circuits 00, the laser light source 10 includes laser components 101 of three primary colors, the plurality of laser components 101 correspond to the plurality of laser drive circuits 00 one by one, and the laser components include at least one laser.

The display control circuit 70 is configured to generate a plurality of enable signals corresponding to the three primary colors of each frame of image one to one, transmit the plurality of enable signals to the corresponding laser driving circuits 00, and generate a plurality of current control signals corresponding to the three primary colors of each frame of image one to one, and transmit the plurality of current control signals to the corresponding laser driving circuits 00.

Each laser driving circuit 00 is configured to provide a driving current corresponding to a laser component to the laser component connected to the laser driving circuit 00, where the current control signal corresponding to each laser component has a different magnitude when corresponding to at least two frames of display images.

The laser assembly 101 is used for emitting light under the driving of the corresponding laser driving circuit 00.

Fig. 2 assumes that the primary colors are red, green, and blue, the corresponding enable signals are a red enable signal R _ EN, a green enable signal R _ EN, and a blue enable signal R _ EN, respectively, and the current control signals are a red current control signal R _ PWM, a green current control signal G _ PWM, and a blue current control signal B _ PWM, respectively. For convenience of illustration, the following embodiments are all described by taking the foregoing primary colors as red, green and blue as examples, and when the embodiments of the present invention are actually implemented, the primary colors may have other colors, which is not limited herein.

In summary, since the display control circuit in the laser projection apparatus may generate a plurality of enable signals corresponding to three primary colors of each frame of image in the multiple frames of display images one by one, respectively transmit the plurality of enable signals to the corresponding laser driving circuits, and generate a plurality of current control signals corresponding to three primary colors of each frame of image one by one, respectively transmit the plurality of current control signals to the corresponding laser driving circuits, each laser driving circuit may provide the laser components connected thereto with driving currents corresponding to the laser components. Because the current control signals corresponding to each laser component have different sizes when corresponding to at least two frames of display images, the laser projection equipment can support the laser components with variable brightness, and the display effect of the laser projection equipment is effectively improved.

As shown in fig. 3, each laser driving circuit 00 includes:

the driving circuit comprises a driving chip 01, a voltage output circuit 02 and a light source switch circuit 03, wherein the light source switch circuit 03 is used for being connected with a laser assembly, and the laser assembly comprises at least one laser for emitting laser light of one color. When the laser assembly comprises a plurality of lasers, the plurality of lasers may be connected in series or in parallel. Illustratively, the laser assembly includes 7-9 lasers, such as 8 lasers. For example, the laser assembly may be a red laser assembly, a green laser assembly, or a blue laser assembly.

And the driving chip 01 is configured to receive a current control signal corresponding to the laser component, and provide a driving current of the corresponding laser component to the light source switching circuit 03 based on the current control signal. In general, the current control signal is Pulse Width Modulation (PWM), the PWM signal is a signal composed of a series of Pulse signals with equal amplitude, and the PWM value is an average value of the summation of the conduction time lengths of the switching tubes in one driving period. The longer the on-time, the larger the average value of the direct current output; the PWM frequency is a ratio of the duration of the on period to the duration of the drive period within a period, also referred to as the duty cycle.

The driving chip 01 is further configured to receive an enable signal corresponding to the laser component, and control, based on the enable signal, a lighting duration of the corresponding laser component driven by the light source switching circuit 03 through the switch control signal. For example, if the laser component is a red laser component, the enable signal is a red enable signal.

And the voltage output circuit 02 is used for providing the rated voltage of the laser component for the light source switching circuit 03. The nominal voltage of the laser assembly is the voltage required for the laser assembly to operate properly, also known as the nominal voltage.

And the light source switch circuit 03 is used for conducting when the switch control signal is an effective potential, and providing a driving current corresponding to the laser component connected with the light source switch circuit under a rated voltage.

For example, as shown in fig. 4, the driving chip 01 includes a first pin ENOUT, a second pin ISN, and a third pin ISP, the first pin ENOUT is used for outputting a switching control signal, and the light source switching circuit 03 includes: a current sense resistor R5 and a first switching transistor Q1. The switch control signal is used for controlling the on and off of the light source switch circuit, so that the light source switch circuit drives the lighting time of the corresponding laser component.

One end of the current detection resistor R5 is connected to the rated voltage output end and the second pin ISN of the voltage output circuit (not shown in fig. 4), and the other end is connected to the anode and the third pin ISP of the laser device, respectively, in fig. 4, it is assumed that the voltage at one end of the current detection resistor R5 is the rated voltage Vo, and the voltage at the other end is the output voltage Vout, the source S1 of the first switching transistor Q1 is connected to the cathode of the laser device, the gate G1 of the first switching transistor Q1 is connected to the first pin ENOUT, the drain D1 of the first switching transistor is connected to the first signal output end O1, the first signal output end O1 is used to output a level signal lower than the level of the drain D1 of the first switching transistor, fig. 4 is described by taking as an example that the drain D1 of the first switching transistor is grounded, and the first signal output end O1 is referred to the ground. When the light source switching circuit 03 is turned on, a current loop h1 is formed. It should be noted that fig. 4 assumes that the laser assembly includes n lasers, i.e., the lasers LD1 to LDn, connected in series. The lasers LD1 to LDn do not belong to the light source switching circuit 03. Optionally, the first switch transistor Q1 may be an N-Metal-Oxide-Semiconductor (NMOS) transistor.

The driver chip 01 is configured to detect a current loaded on the current detection resistor R5 through the second pin ISN and the third pin ISP, and adjust the current loaded on the current detection resistor R5 to a driving current of a corresponding laser component. Referring to fig. 4, the current I is (Vo-Vout)/R, where R represents the resistance of the resistor R5, and I represents the current flowing through the current detection resistor R5.

It should be noted that the driving chip 01 can determine the driving current (i.e. the value of the driving current) corresponding to the laser component in various ways. In an optional mode, after receiving the current control signal, the driving chip 01 calculates a value of the driving current corresponding to the laser component through a first preset algorithm; in another optional mode, the driving chip 01 prestores a corresponding relationship between the current control signal and the current, and after receiving the current control signal, the driving chip 01 queries the corresponding relationship to obtain the corresponding driving current. For example, when the current control signal is a PWM signal, the correspondence relationship between the current control signal and the current may be characterized by a correspondence relationship between a PWM value and a current. Referring to table 1 and fig. 5, for the convenience of the reader to understand, table 1 shows a correspondence table of PWM values, currents and luminances (in practical applications, the driving chip 01 only needs to pre-store the correspondence table of PWM values and currents), and fig. 5 is a graph of a relationship between currents and luminances corresponding to the correspondence table. As can be seen from fig. 5, there is a linear relationship between the current and the brightness, and generally the brightness is larger when the current is larger, so that the brightness of the laser component can be effectively adjusted by adjusting the current of the laser component. For example, when the PWM value of the received PWM signal is 1023 and the driving current obtained by looking up table 1 is 2.6A (ampere), the current loaded on the current detection resistor R5 is adjusted to 2.6A. The brightness of the final laser assembly was 2540lumen (lumens).

TABLE 1

As mentioned above, the current control signal may be a PWM signal, and the PWM signal may generate a certain attenuation during transmission, and the attenuation causes the amplitude (also called high level amplitude) of the PWM signal to be lower than the full scale amplitude that is effectively set. The embodiment of the invention provides a repeater, which can adjust the received PWM signal with the amplitude lower than the full-scale amplitude into the PWM signal with the amplitude of the full-scale amplitude without changing the duty ratio of the PWM signal, so that the signal attenuation caused by signal transmission is avoided, the accuracy of a current control signal input into a driving chip is ensured, and the subsequent driving precision is improved.

As shown in fig. 6, when the current control signal is a PWM signal, the laser driving circuit 00 further includes:

and the repeater 04 is connected with the driving chip 01 and is positioned at the front end of the driving chip 01, and the repeater 04 is used for receiving the current control signal corresponding to the laser component and outputting the current control signal with the amplitude equal to the rated amplitude voltage VCC to the driving chip 01.

Illustratively, as shown in fig. 7, the repeater 04 includes:

the operational amplifier circuit comprises a first resistor R1, a second resistor R2 and an operational amplifier (also called an operational amplifier) P, wherein the first resistor R1 and the second resistor R2 are equal in resistance value, a same-direction input end (also called a non-inverting input end) u + of the operational amplifier P is respectively connected with one end of the first resistor R1, one end of the first resistor R1 is an input end of a current control signal, an inverting input end (also called an inverting input end) u-of the operational amplifier P is connected with one end of the second resistor R2, an output end (also called a common end) o of the operational amplifier P is connected with the other end of the second resistor R2, an output end o of the operational amplifier P is further connected with a driving chip, and the rated voltage (also called an operating voltage) of the operational amplifier P is an amplitude voltage VCC. The ground terminal of the operational amplifier P is connected to a second signal output terminal O2, the second signal output terminal O2 is used for providing a level signal lower than the amplitude voltage VCC, and the second signal output terminal O2 is normally a reference ground.

In practical implementation of the embodiment of the present application, since the rated voltages of the repeater and the driver chip may be different, a third resistor R3 and a fourth resistor R4 are further connected in series between the output terminal O of the operational amplifier P and the third signal output terminal O3, the third signal output terminal O3 is used for providing a level signal lower than the level of the output terminal O, for example, the third signal output terminal O3 is grounded. The third resistor R3 and the fourth resistor R4 are voltage dividing resistors, a node e between the third resistor R3 and the fourth resistor R4 is used for outputting a current control signal after voltage division processing, and the voltage output by the node e is the rated voltage of the driving chip. The resistance values of the third resistor R3 and the fourth resistor R4 are set according to the rated voltages of the repeater and the driver chip.

As shown in fig. 8, since the resistances of the first resistor R1 and the second resistor R2 are equal, after the PWM signal passes through the operational amplifier P, the duty ratio of the PWM signal is not changed, but the amplitude of the PWM signal is adjusted from being lower than the amplitude voltage VCC to being equal to the amplitude voltage VCC, i.e., to be a full scale, so that the processed current control signal is ensured to have no attenuation with respect to the initially generated current control signal.

In addition, the repeater has the characteristics of high input impedance and low output impedance. The signal loss generated when the output impedance is higher and the input impedance of the next stage is lower can be avoided to a certain extent, and the effect of starting and stopping, namely the buffering effect, is achieved. The repeater has the characteristics of high input impedance and low output impedance, so that the repeater presents a high-impedance state for a previous-stage circuit and presents a low-impedance state for a next-stage circuit, and the repeater is commonly used for an intermediate stage to isolate front-stage and rear-stage circuits and eliminate mutual influence between the front-stage and rear-stage circuits. In the embodiment of the invention, the repeater can isolate various noises generated by a circuit (such as a display control circuit) at the front end of the driving chip, so that the precision of the laser driving circuit can be improved.

In different application scenarios, the voltage output circuit 02 may be divided into a boost circuit or a buck circuit according to different operation modes. The voltage boosting circuit is a circuit for boosting an input voltage Vi to a rated voltage Vo of the laser component, Vi is less than Vo, and the voltage reducing circuit is a circuit for reducing the input voltage Vi to the rated voltage Vo of the laser component, Vi is greater than Vo. Because the initial input voltage Vi of the booster circuit is lower relative to the voltage reduction circuit, if the booster circuit has faults such as short circuit, the lower initial input voltage Vi does not exceed the rated voltage Vo of the laser component, the laser component cannot be damaged, and the electric shock risk of a human body cannot be caused. Therefore, the booster circuit is less likely to damage the device than the step-down circuit, and is highly safe.

Illustratively, when the voltage output circuit 02 is a booster circuit, the booster circuit is configured to boost the input voltage Vi to a rated voltage Vo of the laser component and to load the rated voltage Vo to the light source switching circuit 03.

As shown in fig. 9, the boosting circuit may include: the voltage regulator comprises an inductor L, a second switching transistor Q2, a diode D, a capacitor C1, a fifth resistor R6, a sixth resistor R7 and a seventh resistor R8, wherein one end of the inductor L is connected with a supply end a of an input voltage, the other end of the inductor L is respectively connected with the anode of the diode D and a source S2 of the second switching transistor Q2, the cathode of the diode D is an output end of a rated voltage Vo, one end of the capacitor C1 is connected with the output end of the rated voltage Vo, the other end of the capacitor C1 is connected with a fourth signal output end O4, and the fourth signal output end O4 is used for outputting a level signal lower than the rated voltage. Fig. 9 illustrates an example in which the other end of the capacitor C1 is grounded, that is, the fourth signal output terminal O4 is referred to as a ground. The fifth resistor R6 and the sixth resistor R7 are connected in series between the output terminal of the rated voltage and the fifth signal output terminal O5, the fifth signal output terminal O5 is used for outputting a level signal lower than the rated voltage, and fig. 9 illustrates an example in which the fifth resistor R6 and the sixth resistor R7 are connected in series between the output terminal of the rated voltage and ground, that is, the fifth signal output terminal O5 is referred to ground. The seventh resistor R8 is connected in series between the drain D2 of the second switch transistor Q2 and the sixth signal output terminal O6, the sixth signal output terminal O6 is used for outputting a level signal lower than the voltage of the drain D2, and fig. 9 illustrates an example in which the seventh resistor R8 is connected in series between the drain D2 of the second switch transistor Q2 and the ground, that is, the sixth signal output terminal O6 is used as the ground.

In the aforementioned booster circuit, the rated voltage Vo may be set by the node b between the fifth resistor R6 and the sixth resistor R7, and the fifth resistor R6 and the sixth resistor R7, wherein the rated voltage is set

Vb is the reference voltage at node b. Since the voltage rating of the laser assembly is generally constant,therefore, the reference voltage Vb at the node b between the fifth resistor R6 and the sixth resistor R7, and the fifth resistor R6 and the sixth resistor R7 are generally constant, i.e., are constant after being set.

The boost circuit is divided into two working processes, namely a charging process and a discharging process, and in the two working processes, the working principle of the boost circuit is as follows:

and (3) charging process: the second switching transistor Q2 is turned on, the input voltage Vi continuously stores energy in the inductor L, the current in the inductor L increases linearly, and the diode D is turned off in the reverse direction, so that the voltage of the capacitor C1 is prevented from discharging to the fourth signal output terminal O4 (when the fourth signal output terminal O4 is referenced to ground, i.e., discharging to ground), and therefore, the dc power continuously charges the inductor L to store energy, thereby forming a current loop h 2.

And (3) discharging: the second switching transistor Q2 is turned off, which corresponds to the open circuit of the current loop h2, and since the current flowing through the inductor L cannot change abruptly, the current flowing through the inductor L is slowly discharged until it is 0. Since the circuit of the current loop h2 is disconnected, the inductor L can only charge the capacitor C1 through the diode D, so that the electromotive force of the capacitor C1 is continuously increased to form the current loop h 3.

The gate G2 of the second switching transistor Q2 is controlled to enable the second switching transistor Q2 to be continuously turned on and off at a certain frequency, the boosting circuit is controlled to be continuously charged and discharged, the voltage at two ends of the capacitor C1 is continuously boosted until the set rated voltage Vo is reached, and boosting of the boosting circuit is completed.

For example, the second switching transistor Q2 may be an NMOS transistor. When the level signal inputted from the gate G2 is high relative to the level signal of the source S2, the NMOS transistor is turned on, and when the level signal inputted from the gate G2 is low relative to the level signal of the source S2, the NMOS transistor is turned off.

It should be noted that the aforementioned control of turning on and off the second switching transistor Q2, and/or the setting of the reference voltage Vb at the node b between the fifth resistor R6 and the sixth resistor R7 may be controlled by a separate control chip or control circuit, or may be controlled by a driving chip. Fig. 9 assumes that the on and off of the second switching transistor Q2 are controlled by the driver chip 01, and the reference voltage Vb of the node b between the fifth resistor R6 and the sixth resistor R7 is set.

As shown in fig. 10, the driver chip 01 further includes a fourth pin FB, a fifth pin GATE, and a sixth pin SENSE, wherein the fourth pin FB is connected to the node b, and is used for providing a reference voltage Vb to the node b; a fifth pin GATE connected to the GATE G2 of the second switching transistor Q2, the fifth pin GATE being used to control the second switching transistor Q2 to turn on and off; the sixth pin SENSE is connected to a node c between the drain D2 of the second switching transistor Q2 and the seventh resistor R8.

The fifth pin GATE and the sixth pin SENSE may constitute an overcurrent protection circuit. The sixth pin SENSE is used for collecting the current of the voltage boosting circuit by detecting the voltage between the drain D2 and the seventh resistor R8, and when the collected current is greater than the set upper limit threshold of the current, the driving chip controls the fifth pin GATE to turn off the current loop of the voltage boosting circuit. Thereby realizing the overcurrent protection of the booster circuit based on the collected current.

Accordingly, referring to fig. 10, the operation principle of the booster circuit is as follows:

and (3) charging process: the driving chip 01 controls the conduction of the second switching transistor Q2 through the fifth pin GATE, the input voltage Vi continuously stores energy for the inductor L, the current on the inductor L linearly increases, meanwhile, the diode D is reversely cut off, and the direct current continuously charges the inductor L for energy storage, so that a current loop h2 is formed.

And (3) discharging: the driving chip 01 controls the second switching transistor Q2 to turn off through the fifth pin GATE, and the current flowing through the inductor L slowly discharges until it is 0. The electromotive force of the capacitor C1 continuously increases to form a current loop h 3.

The driving chip 01 provides a reference voltage Vb for the node b through the fourth pin FB to set a rated voltage Vo, and then controls the gate G2 of the second switching transistor Q2 to continuously turn on and off the second switching transistor Q2 at a certain frequency, so as to control the boosting circuit to continuously charge and discharge, and continuously raise the voltage at the two ends of the capacitor C1 until the set rated voltage Vo is reached, thereby completing the boosting of the boosting circuit.

For example, the driving chip 01 may control the second switching transistor Q2 to be turned on and off at a frequency of 100kHz (kilohertz) or more, that is, a switching frequency of 100kHz or more. The switching frequency can reduce the sizes of discrete components such as inductors, diodes and the like to the maximum extent, keeps higher driving efficiency, ensures that the temperature rise of the generated discrete components is smaller, the heat is easier to control, and avoids overheating of a driving circuit.

Referring to fig. 11, fig. 11 is a schematic structural diagram of a laser driving circuit according to an embodiment of the present invention, where the driving chip includes: the connection relationship and the operation principle of the first pin ENOUT, the second pin ISN, the third pin ISP, the fourth pin FB, the fifth pin GATE, the sixth pin SENSE, the seventh pin CTRL, and the eighth pin EN refer to the contents of fig. 3, fig. 4, and fig. 10 in the foregoing embodiments, and in a normal case, the current control signal and the enable signal are generated by the display control circuit, and the seventh pin CTRL is used to receive the current control signal, which may be directly connected to the display control circuit or connected to the repeater 04 for repeating by the repeater 04. In fig. 11, the seventh pin CTRL is connected to the repeater 04 and is used for receiving the current control signal processed by the repeater. The eighth pin EN is used for receiving an enable signal, which may be directly connected to the display control circuit.

For the convenience of the reader, the laser driving circuit is described below by taking fig. 11 as an example: after receiving the current control signal transmitted by the repeater 04 through the seventh pin CTRL, the driving chip 01 provides a driving current corresponding to the laser device component to the light source switching circuit 03 based on the current control signal. The driving chip 01 receives an enable signal corresponding to the laser component through an eighth pin EN, and controls the time length for the light source switch circuit 03 to drive the corresponding laser component to be turned on through a switch control signal based on the enable signal; a voltage output circuit 02 for providing a rated voltage Vo of the laser component to the light source switching circuit 03; and the light source switching circuit 03 is used for conducting when the switching control signal is an effective potential, and providing a driving current corresponding to the laser component to the connected laser component under the rated voltage Vo. For the specific operation process of each element in fig. 11, reference may be made to the foregoing embodiment, which is not described herein again.

In the embodiment of the present invention, the driving chip 01 may adopt various ways to adjust the current (i.e. adjust the current value), and in combination with the foregoing embodiment, the embodiment of the present invention is described by taking the following two alternative ways as examples:

in a first alternative, the adjustment of the current is realized by adjusting the value of a current control signal sent by the driver chip (e.g. a current control signal sent by the aforementioned main controller). For example, when the current control signal is a PWM signal, the current value can be adjusted by adjusting the PWM value of the PWM signal. The driving chip is used for adjusting the value of the current control signal so as to adjust the current loaded on the current detection resistor to the driving current of the corresponding laser component.

Referring to fig. 4, the driving current I of the laser device is (VCTRL-100 mV)/(R10), wherein R is the resistance of the resistor R5, VCTRL is the average voltage amplitude of the PWM signal, i.e., the average voltage amplitude of the signal received by the seventh pin CTRL, under the condition that the resistance of the resistor R5 is not changed, the adjustment of the current I is adjusted by the average voltage amplitude VCTRL of the PWM signal, the driving current I of the laser assembly is proportional to the average voltage amplitude VCTRL of the signal received by the seventh pin CTRL (when the laser driving circuit 00 includes the relay 04, VCTRL is the average voltage amplitude of the PWM signal output through the relay 04; when the laser driving circuit 00 does not include the relay 04, VCTRL is the average voltage amplitude of the PWM signal), and the driving current rapidly responds to the change of the gray level value of the pixel of each frame image along with the current change corresponding to the brightness value of each pixel in each frame image.

In a second alternative, the current detection resistor R5 is an adjustable resistor, and the driving chip is configured to adjust the resistance of the resistor detection resistor R5, so as to adjust the current loaded on the current detection resistor R5 to the driving current of the corresponding laser module. It should be noted that the current detection resistor R5 may include one or more resistors, and when the current detection resistor R5 includes a plurality of resistors, the plurality of resistors may be connected in series or in parallel, and the current detection resistor R5 may also be an equivalent resistor implemented by using other components or circuits, which is not limited in this embodiment of the present invention.

For example, when the two implementation manners are combined, the current detection resistor R5 is an adjustable resistor, and the driving chip adjusts the current of the current detection resistor R5 to the driving current of the corresponding laser module by synchronously adjusting the value of the current control signal and adjusting the resistance of the resistance detection resistor R5.

In the laser projection device, the display control circuit generates a plurality of current control signals corresponding to three primary colors one by one, for example, the three primary colors are red, green and blue, the display control circuit generates a red current control signal, a green current control signal and a blue current control signal, and accordingly, the red laser component, the green laser component and the blue laser component are turned on in a time sequence within one driving period. Taking the laser driving circuit of the red laser component shown in fig. 11 as an example, assuming that the driving period of each frame of image of one frame is T, the high level is the active potential, and the on duration (i.e., the lighting duration) of the red laser component in one driving period T is T, the high level duration of the enable signal of the red laser component in one driving period T is T, and the enable signal is input to the enable pin (i.e., the eighth pin) EN of the driving chip 01, and the on-off of the light source switch circuit is controlled by the first pin ENOUT, so as to implement the lighting and the extinguishing of the red laser component. When the first pin ENOUT is at a high level, the first switching transistor Q1 is turned on, the light source switching circuit is turned on and works normally, the turn-on duration of the red laser component is T, when the first pin ENOUT is at a low level, the first switching transistor Q1 is turned off, the light source switching circuit is not turned on, the red laser component does not work, and the turn-off duration of the red laser component is T-T. Further, by controlling the on and off of the first switching transistor Q1, self-protection of the switch control circuit, such as overcurrent protection, can also be achieved.

In the light source switch circuit 03, when the first switch transistor Q1 is an MOS transistor, such as an NMOS transistor, the on-off time of the light source switch circuit reaches ns (nanosecond) level, and the on-off time of the laser drive circuit reaches μ s (microsecond) level, so that the current response speed of the laser component is high, the precision is high, the current and the ripple are high, and the problem of serious color mixing of a plurality of primary color lights due to the slow reaction speed of the laser drive circuit is solved.

In summary, in the laser driving circuit provided in the embodiment of the present invention, the display control circuit in the laser projection apparatus may generate a plurality of enable signals corresponding to three primary colors of each frame image in a plurality of frames of display images one to one, respectively transmit the plurality of enable signals to the corresponding laser driving circuits, and generate a plurality of current control signals corresponding to three primary colors of each frame image one to one, respectively transmit the plurality of current control signals to the corresponding laser driving circuits, and each laser driving circuit may provide the laser module connected thereto with a driving current corresponding to the laser module. Because the current control signal corresponding to each laser component has different sizes when corresponding to at least two frames of display images, the laser projection equipment can support the laser component with variable brightness, and the display effect of the laser projection equipment is effectively improved.

With the development of society, people have higher and higher requirements on the display effect of laser projection equipment, and therefore, higher requirements on a series of parameters (such as contrast ratio) influencing the display effect are also provided. Among them, the contrast of the laser projection apparatus is generally classified into a static contrast and a dynamic contrast. Static contrast generally refers to the contrast calculated by using a contrast algorithm established by the American National Standards Institute (ANSI), which refers to the ratio of the luminance of a white area to the luminance of a black area in a picture (i.e., the same frame of image).

The dynamic contrast refers to a brightness-to-darkness ratio of the same frame image in the display process, which is related to the brightness of the laser light source in the display process, that is, the brightness ratio of the brightest white area to the darkest black area in the display process of the frame image. For example, as shown in formula (1), the dynamic contrast C satisfies:

L_wthe brightness L of the brightest white area of the frame image during display_BThe brightness of the darkest black area of the image in the frame during the display process.

From the above formula of dynamic contrast, when L is_wWhen the maximum value is reached, L can be reduced_BThe dynamic contrast is improved. 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, the other factor is the gray-scale value of the image (i.e. the brightness of the image itself), and the superposition of the two factors can finally determine the actual display brightness of one frame of image, so that the display effect can be optimized by adjusting the ratio of the two factors.

In general, the brightness of the image itself in the video displayed by the laser projection device is constantly changed based on the content of the image, and for each frame of image, the laser light source can be adjusted according to the brightness of the image itself, so as to adjust the actual display brightness of the image. For example, when one frame of image is a black image, the actual display brightness of the one frame of image can be made lower than its own brightness by reducing the brightness of the laser light source. In this way, the lower limit value of the actual display luminance of the laser projection apparatus when displaying an image, i.e., the lowest actual display luminance (L) can be reduced by reducing the luminance of the laser light source_B) The dynamic contrast of the laser projection device is improved when the laser projection device displays images. Meanwhile, the brightness of the laser light source is reduced, so that the power consumption of the laser projection equipment is also reduced.

The laser projection equipment provided by the embodiment of the invention can improve the dynamic contrast of the laser projection equipment without changing the actual display brightness of the image. The principle of image display is as follows: the brightness of the laser light source and the gray scale value of the image to be displayed are respectively processed to enhance the detailed expression of the image, so that the brightness of the light source is reduced and the dynamic contrast of the laser projection equipment is improved on the premise of ensuring that the brightness of the displayed image is unchanged. For the convenience of the reader to understand, the embodiment of the present invention will be described with reference to fig. 12 to 14 as an example of the image display principle according to the embodiment of the present invention:

as described in fig. 12 to 14, fig. 12 to 14 show the relationship between the input signal gray-scale value (also referred to as the display gray-scale value or the image luminance itself) and the screen luminance (i.e., the actual display luminance). In fig. 12 to 14, the abscissa represents the input signal gray-scale value, and the ordinate represents the screen brightness. Assuming that the maximum gray-scale value of the image processed by the laser projection apparatus is 256 and the power of the laser light source (since the power of the laser light source is proportional to the brightness of the laser light source, in the embodiment of the present invention, the power of the laser light source is equivalent to the brightness of the laser light source) is a standard quantity (i.e. a reference quantity), for example, one unit, then, as shown in fig. 12, the curve (i.e. gamma curve) of the gray-scale value of the input signal of the laser projection apparatus and the brightness of the screen is the solid line in fig. 12. Assuming that the input signal gray-scale value of the currently displayed frame image a is 160, the corresponding screen brightness is 96, and as shown in fig. 13, the input signal gray-scale value of the frame image a is gained by D times, and the frame image a is converted into an image a ', and the screen brightness of the image a' is 192. As shown in fig. 14, image a' can be converted to image a by reducing the power of the laser light source to reduce the screen brightness to 96. Therefore, the larger the range of the display gray scale value of the image is, the richer the detailed expression of the image is, but the laser projection device provided by the embodiment of the invention can expand the range of the display gray scale value of the image, that is, the upper limit value of the display gray scale value is improved, so that the detailed expression of the image is enhanced, and meanwhile, on the premise of ensuring that the actual display brightness of the image A is not changed, the brightness of the laser light source is reduced, the contrast is improved, and the power consumption is reduced.

Alternatively, as shown in fig. 15, the laser projection apparatus further includes a light modulation Device 80, and the light modulation Device 80 may be a Digital Micro mirror Device (DMD) or a Liquid Crystal On Silicon (LCOS).

Further, the display control circuit 70 includes: the laser driving circuit comprises an algorithm processor 701 and a control processing module 702, wherein the algorithm processor 701 is connected with the control processing module 702, and the control processing module 702 is further connected with the laser driving circuit 00 and the optical modulation device 80 respectively. The algorithm processor may be implemented using a Field-Programmable Gate Array (FPGA).

The algorithm processor 701 is configured to determine a gain value α of each frame of image according to a gray-scale value of each frame of image in the multi-frame display image, where α is greater than or equal to 1. The image display data of each frame of image may reflect the basic distribution and the basic tone of the color of each frame of image, and when the image display data is 4K data, the 4K data may be input to the algorithm processor 701 in the form of a V-by-One (a digital interface standard developed for image transmission).

The algorithm processor 701 is further configured to send image display data and current control signals corresponding to the laser assemblies to the control processing module 702, where each current control signal is used to indicate an adjusted brightness of the corresponding laser assembly, the adjusted brightness is 1/α of the brightness before adjustment, the image display data is used to indicate a gray level value of each frame of image after adjustment, and the gray level value after adjustment is α times of the gray level value before adjustment.

The control processing module 702 is configured to send image display data to the light modulation device 80 and send a current control signal corresponding to the laser component to the laser driving circuit.

And the optical modulation device 80 is configured to modulate a light beam of the laser light source based on the image display data to generate an image light beam, and project the image light beam onto the display screen to realize display of each frame of image. It should be noted that the laser projection apparatus may further include a plurality of optical lenses, which are located between the light modulation device 80 and the display screen, and are used for projecting the image beam onto the display screen after transmitting, reflecting and/or refracting the image beam.

In the embodiment of the present invention, the display control circuit 70 may adjust the brightness of the laser light source in real time based on the gain value α of each frame of image, that is, the change of each frame of image, so as to implement the dynamic contrast. In the light source switch circuit of the laser driving circuit, when the first switch transistor is an MOS transistor, such as an NMOS transistor, the on-off time of the light source switch circuit reaches ns (nanosecond) level, and the on-off time of the laser driving circuit reaches mus (microsecond) level, so that the current response speed of the laser component is high, the precision is high, namely the laser driving circuit can quickly and accurately respond to the change of the brightness of each pixel of an image, the brightness of the laser component can be randomly adjusted from 0 to the brightness corresponding to a rated current value, the image quality problem of serious color mixing of various basic color lights caused by the slow reaction speed of the laser driving circuit is solved, and the driving circuit is the basis for realizing high dynamic contrast, namely supports the dynamic brightness adjustment of the laser projection equipment on hardware.

With the improvement of the resolution of the laser projection device, the image display data of the laser projection device is larger and larger, for example, the image display data is 4K data, that is, data with a pixel resolution of 4096 × 2160, and the display control circuit 70 only uses one processor, which easily causes the processing efficiency of the processor to be low. As shown in fig. 16, the control processing module 702: the main control processor 7021 and the slave control processor 7022, the algorithm processor 701 is respectively connected with the main control processor 7021 and the slave control processor 7022, the main control processor 7021 is further respectively connected with the laser driving circuit 00 and the optical modulation device 80, and the slave control processor 7022 is further connected with the optical modulation device 80.

And the algorithm processor 701 is used for determining the gain value alpha of each frame image according to the gray-scale value of each frame image, wherein alpha is more than or equal to 1.

The algorithm processor 701 is further configured to send the current control signal and the first sub-data to the master control processor 7021, and send the second sub-data to the slave control processor, where the first sub-data and the second sub-data constitute image display data.

For example, when the image display data is 4K data, the first sub-data and the second sub-data are both 60bit data, and both the first sub-data and the second sub-data may be Low-Voltage Differential Signaling (LVDS), where the first sub-data is two-way west LVDS and the second sub-data may be two-way east LVDS.

Optionally, the algorithm processor 701 may generate the current control signal in multiple ways, and in an optional way, after the algorithm processor 701 determines the gain value α of each frame image, the brightness of each laser component is calculated, and the current control signal is generated based on the brightness through a second preset algorithm; in another alternative, the algorithm processor 701 may pre-store a corresponding relationship between the current control signal and the brightness, after the gain value α of each frame image is determined, the algorithm processor 701 calculates the brightness of each laser component, and then queries the corresponding relationship according to the calculated brightness to obtain the current control signal corresponding to the laser component. For example, when the current control signal is a PWM signal, the correspondence relationship between the current control signal and the current can be characterized by the correspondence relationship between the PWM value and the brightness. The correspondence relationship may refer to the correspondence relationship between the PWM value and the brightness in table 1.

And a main control processor 7021 configured to send the current control signal and the enable signal to the laser driving circuit 00, and send the first sub data to the optical modulation device.

And a slave processor 7022 for sending the second sub-data to the light modulation device 80.

The optical modulation device 80 is configured to modulate a light beam of the laser light source based on the first sub data and the second sub data to generate an image light beam, and project the image light beam onto the display screen to realize display of each frame of image.

Further optionally, as shown in fig. 17, the laser projection apparatus further includes: a memory 90, a mirror driving circuit 100, a mirror 110 and a power module 120, wherein the memory 90 is connected to the algorithm processor 701 and is used for storing image display Data, please refer to fig. 15 and 16, that is, storing the adjusted gray level value of each frame of image, for example, the memory is a Double Data Rate (DDR) memory; the galvanometer driving circuit 100 is connected to the algorithm processor 701 and the galvanometer 110, and is configured to drive the galvanometer 110 to vibrate under the control of the algorithm processor 701, for example, the galvanometer 110 may be a 4-dimensional galvanometer, that is, may vibrate in 4 directions, and by setting the galvanometer driving circuit 100 and the galvanometer 110, image superposition display may be performed, so that detail expressive force is increased, which is equivalent to resolution improvement; the power module 120 is used for supplying power to the power consuming components, and is connected to each power consuming component in the laser projection device, and fig. 17 is only schematically illustrated by its connection to the algorithm processor 701, the master control processor 7021, and the slave control processor 7022.

It is worth mentioning that the laser projection apparatus may further include: the functions of the two dichroic mirrors 20, the reflecting mirror 30, the condensing lens 40, the diffusion wheel 50, the light bar 60, and the like can refer to fig. 1, and the description of the embodiments of the present invention is omitted.

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

It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims

1. A laser projection device, comprising:

2. The machine-light projection device of claim 1, wherein each of the laser drive circuits comprises: the driving circuit comprises a driving chip, a voltage output circuit and a light source switching circuit, wherein the light source switching circuit is used for being connected with a laser component;

the driving chip is used for receiving a current control signal corresponding to the laser component and providing a driving current of the corresponding laser component to the light source switch circuit based on the current control signal;

the driving chip is further configured to receive an enable signal corresponding to the laser component, and control, based on the enable signal, a time duration for the light source switching circuit to drive the corresponding laser component to be turned on through the switch control signal;

the voltage output circuit is used for providing rated voltage of the laser component for the light source switch circuit;

and the light source switch circuit is used for conducting when the switch control signal is an effective potential and providing a driving current corresponding to the laser component connected with the light source switch circuit under the rated voltage.

3. The machine light projection device of claim 2,

the driving chip comprises a first pin, a second pin and a third pin, wherein the first pin is used for outputting the switch control signal;

the light source switching circuit includes: a current detection resistor and a first switching transistor;

one end of the current detection resistor is connected with the rated voltage output end of the voltage output circuit and the second pin, the other end of the current detection resistor is connected with the anode of the laser component and the third pin, the source electrode of the first switch transistor is connected with the cathode of the laser component, the grid electrode of the first switch transistor is connected with the first pin, and the drain electrode of the first switch transistor is connected with a low potential;

the driving chip is configured to detect a current loaded on the current detection resistor through the second pin and the third pin, and adjust the current loaded on the current detection resistor to a driving current corresponding to the laser component.

4. The machine-light projection device of claim 3, wherein the driving chip is configured to adjust the value of the current control signal to adjust the current loaded on the current detection resistor to the driving current of the corresponding laser component;

and/or the current detection resistor is an adjustable resistor, and the driving chip is used for adjusting the resistance value of the resistor detection resistor so as to adjust the current loaded on the current detection resistor to the driving current of the corresponding laser component.

5. The machine-light projection device of claim 2, wherein the current control signal is a PWM signal, the laser drive circuit further comprising:

the repeater is connected with the driving chip and used for receiving a current control signal corresponding to the laser component and outputting the current control signal with the amplitude equal to the rated amplitude voltage to the driving chip.

6. The machine-light projection device of claim 5, wherein the relay comprises:

a first resistor, a second resistor and an operational amplifier;

the resistance values of the first resistor and the second resistor are equal, the homodromous input end of the operational amplifier is connected with one end of the first resistor, one end of the first resistor is the input end of the current control signal, the reverse input end of the operational amplifier is connected with one end of the second resistor and the second signal output end, the output end of the operational amplifier is connected with the other end of the second resistor and the driving chip, and the rated voltage of the operational amplifier is the amplitude voltage.

7. The machine light projection device of claim 2,

the voltage output circuit is a booster circuit, and the booster circuit is used for boosting input voltage to rated voltage of the laser component and loading the rated voltage for the light source switch circuit.

8. The machine-light projection device of claim 7, wherein the boost circuit comprises:

the inductor, the second switching transistor, the diode, the capacitor, the fifth resistor, the sixth resistor and the seventh resistor;

one end of the inductor is connected with a supply end of input voltage, the other end of the inductor is respectively connected with the anode of the diode and the source electrode of the second switching transistor, and the cathode of the diode is an output end of rated voltage;

one end of the capacitor is connected with the output end of the rated voltage, the other end of the capacitor is connected with a fourth signal output end, and the fourth signal output end is used for outputting a level signal lower than the rated voltage;

the fifth resistor and the sixth resistor are connected in series between the output end of the rated voltage and a fifth signal output end, and the fifth signal output end is used for outputting a level signal lower than the rated voltage;

the seventh resistor is connected in series between the drain of the second switching transistor and a sixth signal output terminal for outputting a level signal of a voltage lower than the drain.

9. A laser projection device as claimed in any one of claims 1 to 8, wherein the laser projection device further comprises a light modulation device, and the display control circuit comprises: the laser comprises an algorithm processor and a control processing module, wherein the algorithm processor is connected with the control processing module, and the control processing module is also respectively connected with the laser driving circuit and the light modulation device.

10. The laser projection device of claim 9, wherein the control processing module comprises: a master processor and a slave processor, the algorithm processor is respectively connected with the master processor and the slave processor, the master processor is also respectively connected with the laser driving circuit and the optical modulation device, the slave processor is also connected with the optical modulation device,

the algorithm processor is used for determining the gain value alpha of each frame of image according to the gray-scale value of each frame of image, and alpha is more than or equal to 1;

the arithmetic processor is further configured to send the current control signal and first sub-data to the master control processor, and send second sub-data to the slave control processor, where the first sub-data and the second sub-data constitute image display data, each current control signal is used to indicate an adjusted brightness of the corresponding laser component, the adjusted brightness is 1/α of a brightness before adjustment, the image display data is used to indicate a gray level value of each frame of image after adjustment, and the adjusted gray level value is α times of the gray level value before adjustment;

the main control processor is used for sending a current control signal and the enabling signal to the laser driving circuit and sending first subdata to the optical modulation device;

the slave control processor is used for sending the second subdata to the optical modulation device;

the light modulation device is used for modulating the light beam of the laser light source based on the first subdata and the second subdata to generate an image light beam.