Patent Publication Number: US-2022215781-A1

Title: Projection apparatus and projection method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation Application of International Patent Application No. PCT/CN2021/089268 filed on Apr. 23, 2021, which claims priority to Chinese Patent Application No. 202010555370.7 filed on Jun. 17, 2020, and the entireties are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of projection display, and in particular, to a projection apparatus and a projection method thereof. 
     BACKGROUND 
     With the development of laser technologies, laser projection apparatuses have been used widely. In some situations, a laser projection apparatus includes not only a projector but also a projection screen. The projector may project laser beams to the projection screen according to an image to be displayed, so as to display the image on the projection screen. 
     SUMMARY 
     In an aspect, a projection apparatus is provided. The projection apparatus includes a main control circuit, a power supply, a display driving circuit, an audio playback component and a display component. The main control circuit is coupled with the power supply, the display driving circuit and the audio playback component. The main control circuit is coupled with the display component through the display driving circuit. The power supply is coupled with the display driving circuit and the audio playback component. 
     The main control circuit is configured to receive a standby command, send a power-off command to the power supply in response to the standby command, receive a turn-on command, and send a power-on command to the power supply in response to the turn-on command. The power supply is configured to receive the power-off command, stop supplying power to the display driving circuit in response to the power-off command, receive the power-on command, and supply power to the display driving circuit in response to the power-on command. 
     The main control circuit is further configured to send a first image signal to the display driving circuit. The display driving circuit is configured to receive the first image signal and control the display component to display an image corresponding to the first image signal. The main control circuit is further configured to send a second image signal and an audio signal corresponding to the second image signal to the display driving circuit and the audio playback component respectively. An image corresponding to the second image signal is an image displayed by the display component when the main control circuit receives the standby command. The display driving circuit is configured to receive the second image signal and control the display component to display the image corresponding to the second image signal. The audio playback component is configured to receive the audio signal corresponding to the second image signal and play audio corresponding to the audio signal. 
     In another aspect, a projection apparatus is provided. The projection apparatus includes a main control circuit, a power supply, a display driving circuit, an audio playback component and a display component. The main control circuit is coupled with the power supply, the display driving circuit and the audio playback component. The main control circuit is coupled with the display component through the display driving circuit. The power supply is coupled with the display driving circuit and the audio playback component. 
     The main control circuit is configured to receive a standby command, send a power-off command to the power supply in response to the standby command, receive a turn-on command, and send a power-on command to the power supply in response to the turn-on command. The power supply is configured to stop supplying power to the display driving circuit in response to the power-off command and supply power to the display driving circuit in response to the power-on command. 
     The main control circuit is further configured to send a second image signal and an audio signal corresponding to the second image signal to the display driving circuit and the audio playback component respectively, in a case where it is determined that the display component is in an ON state. An image corresponding to the second image signal is an image displayed by the display component when the main control circuit receives the standby command. The display driving circuit is configured to receive the second image signal and control the display component to display the image corresponding to the second image signal. The audio playback component is configured to receive the audio signal corresponding to the second image signal and play audio corresponding to the audio signal. 
     In yet another aspect, a projection method of a projection apparatus is provided. The projection apparatus includes a main control circuit, a power supply, a display driving circuit, an audio playback component and a display component. The main control circuit is coupled with the power supply, the display driving circuit and the audio playback component. The main control circuit is coupled with the display component through the display driving circuit. The power supply is coupled with the display driving circuit and the audio playback component. 
     The projection method includes: the main control circuit receiving a standby command when the display component displays a second image; the main control circuit sending a power-off command to the power supply in response to the standby command; the power supply receiving the power-off command and stopping supplying power to the display driving circuit in response to the power-off command; the main control circuit receiving a turn-on command and sending a power-on command to the power supply in response to the turn-on command; the power supply receiving the power-on command and supplying power to the display driving circuit in response to the power-on command. 
     The projection method further includes: the main control circuit sending a first image signal to the display driving circuit; the display driving circuit receiving the first image signal and controlling the display component to display an image corresponding to the first image signal; the main control circuit sending a second image signal and an audio signal corresponding to the second image signal to the display driving circuit and the audio playback component respectively; the display driving circuit receiving the second image signal and controlling the display component to display an image corresponding to the second image signal; and the audio playback component receiving the audio signal corresponding to the second image signal and playing audio corresponding to the audio signal. 
     In yet another aspect, a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium stores computer program instructions that, when executed by a projection apparatus, perform the projection method of the projection apparatus as described above. 
     In yet another aspect, a computer program product stored on a non-transitory computer readable storage medium is provided. The computer program product includes computer program instructions, and the computer program instructions cause a computer to perform the projection method of the projection apparatus as described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe technical solutions in the present disclosure more clearly, accompanying drawings to be used in some embodiments of the present disclosure will be introduced briefly below. However, the accompanying drawings to be described below are merely accompanying drawings of some embodiments of the present disclosure, and a person of ordinary skill in the art may obtain other drawings according to these drawings. In addition, the accompanying drawings to be described below may be regarded as schematic diagrams, and are not limitations on actual sizes of products, actual processes of methods and actual timings of signals to which the embodiments of the present disclosure relate. 
         FIG. 1  is a diagram showing a structure of a laser projection apparatus, in accordance with some embodiments of the present disclosure; 
         FIG. 2  is a diagram showing a structure of a host in a laser projection apparatus, in accordance with some embodiments of the present disclosure; 
         FIG. 3  is a diagram showing a simplified structure of a laser source, an optical engine, and a projection lens in a laser projection apparatus, in accordance with some embodiments of the present disclosure; 
         FIG. 4  is a diagram showing an optical path of a laser projection apparatus, in accordance with some embodiments of the present disclosure; 
         FIG. 5  is a diagram showing a circuit structure of a laser projection apparatus, in accordance with some embodiments of the present disclosure; 
         FIG. 6  is a diagram showing a circuit structure of a projection apparatus, in accordance with some embodiments of the present disclosure; 
         FIG. 7  is a flow diagram of a projection method of a projection apparatus, in accordance with some embodiments of the present disclosure; 
         FIG. 8  is a flow diagram of another projection method of a projection apparatus, in accordance with some embodiments of the present disclosure; and 
         FIG. 9  is a flow diagram of yet another projection method of a projection apparatus, in accordance with some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Technical solutions in some embodiments of the present disclosure will be described clearly and completely with reference to the accompanying drawings below. However, the described embodiments are merely some but not all embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure shall be included in the protection scope of the present disclosure. 
     Unless the context requires otherwise, throughout the description and the claims, the term “comprise” and other forms thereof such as the third-person singular form “comprises” and the present participle form “comprising” are construed as open and inclusive, i.e., “including, but not limited to”. 
     In the description, the terms such as “one embodiment”, “some embodiments”, “exemplary embodiments”, “example”, “specific example” or “some examples” are intended to indicate that specific features, structures, materials or characteristics related to the embodiment(s) or example(s) are included in at least one embodiment or example of the present disclosure. Schematic representations of the above terms do not necessarily refer to the same embodiment(s) or example(s). In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any suitable manner. 
     Hereinafter, the terms “first” and “second” are used for descriptive purposes only, and are not to be construed as indicating or implying the relative importance or implicitly indicating the number of indicated technical features. Thus, features defined with “first” and “second” may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, “a plurality of/the plurality of” means two or more unless otherwise specified. 
     In the description of some embodiments, the term “coupled” and “connected” and their extensions may be used. For example, the term “connected” may be used in the description of some embodiments to indicate that two or more components are in direct physical or electrical contact with each other. For another example, the term “coupled” may be used in the description of some embodiments to indicate that two or more components are in direct physical or electrical contact. However, the term “coupled” or “communicatively coupled” may also mean that two or more components are not in direct contact with each other, but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the contents herein. 
     The phrase “at least one of A, B and C” has a same meaning as the phrase “at least one of A, B or C”, and both include the following combinations of A, B and C: only A, only B, only C, a combination of A and B, a combination of A and C, a combination of B and C, and a combination of A, B and C. 
     The phrase “A and/or B” includes the following three combinations: only A, only B, and a combination of A and B. 
     As used herein, the term “if”, depending on the context, is optionally construed as “when” or “in a case where” or “in response to determining” or “in response to detecting”. Similarly, the phrase “if it is determined” or “if a stated condition or event is detected”, depending on the context, is optionally construed as “in a case where it is determined” or “in response to determining” or “in a case where the stated condition or event is detected” or “in response to detecting the stated condition or event”. 
     The use of the phrase “applicable to” or “configured to” herein means an open and inclusive language, which does not exclude devices that are applicable to or configured to perform additional tasks or steps. 
     In addition, the use of the phrase “based on” means openness and inclusiveness, because processes, steps, calculations or other actions “based on” one or more of the stated conditions or values may be based on additional conditions or exceed the stated values in practice. 
     As used herein, the term “about”, “substantially” or “approximately” includes a stated value and an average value within an acceptable range of deviation of a particular value. The acceptable range of deviation is determined by a person of ordinary skill in the art, considering measurement in question and errors associated with measurement of a particular quantity (i.e., limitations of a measurement system). 
     As used herein, “parallel”, “perpendicular” and “equal” include the stated conditions and the conditions similar to the stated conditions, and the range of the similar conditions is within the acceptable deviation range, where the acceptable deviation range is determined by a person of ordinary skill in the art in consideration of the measurement in question and the error associated with the measurement of a specific quantity (i.e., the limitation of the measurement system). For example, the term “parallel” includes absolute parallelism and approximate parallelism, and an acceptable range of deviation of the approximate parallelism may be, for example, a deviation within 5°; the term “perpendicular” includes absolute perpendicularity and approximate perpendicularity, and an acceptable range of deviation of the approximate perpendicularity may also be, for example, a deviation within 5°. The term “equal” includes absolute equality and approximate equality, and an acceptable range of deviation of the approximate equality may be, for example, a difference between two equals of less than or equal to 5% of either of the two equals. 
       FIG. 1  is a diagram showing a structure of a laser projection apparatus according to some embodiments of the present disclosure. As shown in  FIG. 1 , the laser projection apparatus includes a host  100  and a projection screen  200 . In some embodiments, the laser projection apparatus further includes a remote controller  300 . The remote controller  300  may send a turn-on command, a turn-off command, a standby command and some adjustment commands, such as a brightness adjustment command, to the host  100 . In some embodiments, the host  100  further includes a touch button  101 . A user may send the turn-on command, the turn-off command, the standby command and the adjustment command to the host  100  through the touch button  101  without using the remote controller. 
       FIG. 2  is a diagram showing a structure of a host in a laser projection apparatus according to some embodiments of the present disclosure. As shown in  FIG. 2 , the host  100  includes an apparatus housing  1000  (only part of the housing  1000  is shown in  FIG. 3 ), and a laser source  1100 , an optical engine  1200  and a projection lens  1300  that are assembled in the apparatus housing  1000 . The laser source  1100  is configured to provide illumination beams (laser beams). The optical engine  1200  is configured to modulate the illumination beams provided by the laser source  1100  with image signals to obtain projection beams. The projection lens  1300  is configured to project the projection beams on the projection screen  200  for imaging. 
     The laser source  1100 , the optical engine  1200  and the projection lens  1300  are sequentially connected in a propagation direction of light beams, and are each wrapped by a corresponding housing. The respective housings of the laser source  1100 , the optical engine  1200  and the projection lens  1300  support corresponding optical components and make the optical components meet certain sealing or airtight requirements. For example, the laser source  1100  is hermetically sealed through its corresponding housing, which may better improve a light attenuation problem of the laser source  1100 . 
     An end of the optical engine  1200  is connected to the projection lens  1300 , and the optical engine  1200  and the projection lens  1300  are disposed in a first direction X. For example, the first direction X may be an exit direction of the projection beams of the host  100 . The other end of the optical engine  1200  is connected to the laser source  1100 . In the example shown in  FIG. 3 , the laser source  1100 , the optical engine  1200  and the projection lens  1300  are connected in an “L” shape. That is, the exit direction of the projection beams of the host  100  is substantially perpendicular to an exit direction of the illumination beams of the host  100 . This connection structure may adapt to characteristics of an optical path of a reflective light valve (which will be described later) in the optical engine  1200 . 
     As shown in  FIGS. 3 and 4 , the laser source  1100  may include three laser arrays. The three laser arrays may be a blue laser array  1110 , a green laser array  1120  and a red laser array  1130 . That is, the laser source  1100  is a tri-color laser source, but it is not limited to this. The three laser arrays may also all be blue laser arrays  1110 , and in this case, the laser source  1100  is a mono-color laser source; alternatively, two laser arrays are blue laser arrays  1110  and one laser array is a red laser array  1130 , and in this case, the laser source  1100  is a dual-color laser source. 
     The illumination beams emitted by the laser source  1100  enter the optical engine  1200 . The optical engine  1200  may include a light pipe  1210 , a lens assembly  1220 , a mirror  1230 , a light valve  1240  (which may be a digital micro-mirror device) and a prism assembly  1250 . The light pipe  1210  may receive the illumination beams provided by the laser source  1100  and homogenize the illumination beams. The lens assembly  1220  may first collimate the illumination beams, and then converge the collimated illumination beams and emit the converged illumination beams to the mirror  1230 . The mirror  1230  may reflect the illumination beams to the prism assembly  1250 . The prism assembly  1250  reflects the illumination beams to the light valve  1240 . The light valve  1240  modulates the illumination beams to obtain the projection beams, and reflects the modulated projection beams into the projection lens  1300 . 
     In the optical engine  1200 , the light valve  1240  is a core component, which plays a role of modulating the illumination beams provided by the laser source  1100  with the image signals. That is, the light valve  1240  changes the illumination beams to form the projection beams according to colors and brightness required by different pixels of an image to be displayed. Depending on whether the light valve transmits or reflects the illumination beams, the light valve may be classified as a transmissive light valve or a reflective light valve. For example, the light valve  1240  shown in  FIG. 4  reflects the illumination beams, and thus it is a reflective light valve. A liquid crystal light valve transmits the illumination beams, and thus it is a transmissive light valve. 
     The projection lens  1300  includes a combination of a plurality of lenses. The projection lens  1300  may be a zoom projection lens, or a prime adjustable-focus projection lens, or a prime projection lens. In some embodiments, the laser projection apparatus is an ultra-short-focus laser projection apparatus. The projection lens  1300  is an ultra-short-focus projection lens, and a projection ratio of the projection lens  1300  is usually less than 0.3, such as 0.24. 
     The host  100  further includes a printed circuit board assembly (PCBA). The printed circuit board assembly in  FIG. 2  is hidden from view by other objects. As shown in  FIG. 5 , the printed circuit board assembly may include a power supply  10 , a display driving circuit  20 , an audio playback component  30 , a display component  40  and a main control circuit  50 . The power supply  10  supplies power to the display driving circuit  20 , the audio playback component  30 , the display component  40  and the main control circuit  50 . The main control circuit  50  is coupled with the display component  40  through the display driving circuit  20 , and the main control circuit  50  is further coupled with the audio playback component  30 . 
     Usually, the main control circuit  50  controls the power supply  10  to stop supplying power to the display driving circuit  20  after receiving a standby command to cause the laser projection apparatus to be in a standby mode, and in this case, the display component  40  is turned off. Moreover, the main control circuit  50  saves an image currently displayed by the laser projection apparatus and audio corresponding to the image. In addition, the main control circuit  50  controls the power supply  10  to supply power to the display driving circuit  20  after receiving a turn-on command indicating that the laser projection apparatus is turned on, so that the display driving circuit  20  turns on the display component  40 . Moreover, the main control circuit  50  sends the saved image to the display driving circuit  20 , and sends the audio corresponding to the image to the audio playback component  30 , so as to continue to display the image displayed when the standby command is received and play sounds played when the standby command is received. 
     However, for some laser projection apparatuses, the power supply only stops supplying power to the display driving circuit during a standby process, but does not stop supplying power to the main control circuit. Therefore, after receiving the turn-on command, the main control circuit may send the saved image to the display driving circuit, and send the audio corresponding to the image to the audio playback component. However, since the display driving circuit will not turn on the display component until the display driving circuit starts, a situation that the audio playback component has already started to play the audio corresponding to the image when the display component has not yet started and displayed the image will occur, so that the played audio is out of sync with the displayed image. 
     To this end, some embodiments of the present disclosure provide a projection apparatus, which may be the above-mentioned laser projection apparatus. The projection apparatus may include a power supply  10 , a display driving circuit  20 , an audio playback component  30 , a display component  40  and a main control circuit  50 . The main control circuit  50  is coupled with the power supply  10 , the display driving circuit  20  and the audio playback component  30 , and the main control circuit  50  is coupled with the display component  40  through the display driving circuit  20 . The power supply  10  is coupled with the display driving circuit  20  and the audio playback component  30 . 
     The main control circuit  50  is configured to receive a standby command, and send a power-off command to the power supply  10  in response to the standby command. The power supply  10  is configured to receive the power-off command and stop supplying power to the display driving circuit  20  in response to the power-off command. In this case, the display component  40  is turned off. 
     In some embodiments, the main control circuit  50  may further be configured to send a shutdown command to the display driving circuit  20  in response to the standby command, before sending the power-off command to the power supply  10 . The display driving circuit  20  is configured to receive the shutdown command and turn off the display component  40  in response to the shutdown command. Then, the main control circuit  50  sends the power-off command to the power supply  10 . That is, the main control circuit  50  may be configured to instruct the display driving circuit  20  to turn off the display component  40  first, before the power supply  10  stops supplying power to the display driving circuit  20 . 
     For example, the above-mentioned standby command may be a standby command sent by the user to the main control circuit  50  through the remote controller  300 , or may be a standby command sent by the user to the main control circuit  50  through the touch button  101 . The present disclosure does not limit a triggering manner of the standby command. 
     In some embodiments, as shown in  FIG. 6 , the display driving circuit  20  may include a display driving sub-circuit  21 , a laser driving sub-circuit  22  and at least one light valve driving sub-circuit  23 . The display driving sub-circuit  21  is coupled with the main control circuit  50 , the laser driving sub-circuit  22  and the light valve driving sub-circuit  23 . For example, the main control circuit  50  may be coupled with the display driving sub-circuit  21  through an inter-integrated circuit (I2C), and the display driving sub-circuit  21  may also be coupled with the laser driving sub-circuit  22  and the light valve driving sub-circuit  23  through the I2C. 
     The projection apparatus may further include a fan  1400  (as shown in  FIG. 2 ), and the fan  1400  is connected with the display driving sub-circuit  21 . The display component  40  may include a light valve  1240  and at least one laser array. The at least one laser array may include at least one of a blue laser array  1110 , a green laser array  1120  or a red laser array  1130 . In some embodiments of the present disclosure, the description is made by considering an example where the at least one laser array includes three laser arrays, and the three laser arrays include a blue laser array  1110 , a green laser array  1120  and a red laser array  1130 . The laser driving sub-circuit  22  is coupled with the laser arrays  1110 ,  1120  and  1130 , and the light valve driving sub-circuit  23  is coupled with the light valve  1240  through a flat cable. 
     In some embodiments, as shown in  FIG. 6 , when the display component  40  displays a second image and the audio playback component  30  plays audio corresponding to the second image, if the user triggers a standby command, the main control circuit  50  is configured to receive the standby command and send a shutdown command to the display driving sub-circuit  21  in response to the standby command. The display driving sub-circuit  21  is configured to receive the shutdown command, turn off the fan  1400  in response to the shutdown command, and send the shutdown command to the laser driving sub-circuit  22  and the light valve driving sub-circuit  23 . The laser driving sub-circuit  22  is configured to receive the shutdown command, and turn off the laser arrays  1110 ,  1120  and  1130  in response to the shutdown command. The light valve driving sub-circuit  23  is configured to receive the shutdown command, and turn off the light valve  1240  in response to the shutdown command. 
     The second image is an image displayed by the display component when the main control circuit receives the standby command. For example, the second image is an image displayed when the projection apparatus is in normal use. 
     In some embodiments, the power supply  10  is configured to stop supplying power to the display driving sub-circuit  21  and the light valve driving sub-circuit  23  in response to the power-off command. The display driving sub-circuit  21  is configured to stop supplying a drive current to the laser driving sub-circuit  22  after being powered off, so as to control the laser driving sub-circuit  22  to be powered off. The laser driving sub-circuit  22  is configured to stop supplying a drive current to the laser arrays  1110 ,  1120  and  1130  after being powered off, so as to control the laser arrays  1110 ,  1120  and  1130  to be turned off. The light valve driving sub-circuit  23  is configured to stop supplying a drive current to the light valve  1240  after being powered off, so as to control the light valve  1240  to be turned off. 
     The main control circuit  50  is further configured to receive a turn-on command, and send a power-on command to the power supply  10  in response to the turn-on command. The power supply  10  receives the power-on command and supplies power to the display driving circuit  20  in response to the power-on command. 
     For example, the above turn-on command may be a turn-on command sent by the user to the main control circuit  50  through the remote controller  300 , or may be a turn-on command sent by the user to the main control circuit  50  through the touch button  101 . The present disclosure does not limit a triggering manner of the turn-on command. 
     In some embodiments, the display driving circuit  20  is further configured to control the display component  40  to be turned on after being powered on, and send a start-up completion command for instructing that the display component  40  is turned on to the main control circuit  50 . 
     As shown in  FIG. 6 , if the user triggers the turn-on command, the main control circuit  50  is configured to receive the turn-on command and send a power-on command to the power supply  10  in response to the turn-on command. The power supply  10  is configured to receive the power-on command and supply power to the display driving sub-circuit  21  and the light valve driving sub-circuit  23  in response to the power-on command. The light valve driving sub-circuit  23  is configured to supply a drive current to the light valve  1240  and turn on the light valve  1240  after it is started up. In this case, the display driving sub-circuit  21  is configured to turn on the fan  1400  and send a start-up command to the laser driving sub-circuit  22  after it is started up. The laser driving sub-circuit  22  is configured to receive the start-up command and be turned on, and supply a drive current to the laser arrays  1110 ,  1120  and  1130  and turn on the laser arrays  1110 ,  1120  and  1130  after it is started up. The display driving sub-circuit  21  is further configured to send a start-up completion command to the main control circuit  50  after the laser arrays  1110 ,  1120  and  1130  are started up. 
     In some embodiments, as shown in  FIG. 6 , the display driving circuit  20  may further include an image processing sub-circuit  24 , a first memory  61  and at least one second memory  62 . The first memory  61  is coupled with the image processing sub-circuit  24 , and the at least one second memory  62  is coupled to the at least one light valve driving sub-circuit  23  respectively. The first memory  61  is configured to store programs for initialization and start-up of the image processing sub-circuit  24 , and a second memory  62  is configured to store programs for initialization and start-up of the light valve driving sub-circuit  23 . The main control circuit  50  is coupled with the light valve driving sub-circuit  23  through the image processing sub-circuit  24 . 
     The power supply  10  is configured to receive a power-off command and stop supplying power to the display driving sub-circuit  21 , the light valve driving sub-circuit  23  and the image processing sub-circuit  24  in response to the power-off command. The power supply  10  is further configured to receive a power-on command and supply power to the display driving sub-circuit  21 , the light valve driving sub-circuit  23  and the image processing sub-circuit  24  in response to the power-on command. After the power supply  10  supplies power to the image processing sub-circuit  24 , the image processing sub-circuit  24  may read the programs stored in the first memory  61  and perform initialization to complete the start-up. Each light valve driving sub-circuit  23  may read programs stored in a second memory  62  connected thereto and perform initialization to complete the start-up. 
     The main control circuit  50  is further configured to send a first image signal to the display driving circuit  20 . The display driving circuit  20  is configured to receive the first image signal and control the display component  40  to display an image corresponding to the first image signal. 
     For example, the image (which may also be referred to as a first image) corresponding to the first image signal is a black image (e.g., a black image card). Before an image (which may also be referred to as a second image, and the second image is an image displayed by the display component when the main control circuit receives the standby command) corresponding to a second image signal is displayed and audio corresponding to the second image is played, a black first image is displayed first, which may not only enable the display component to be turned on before the display component displays the second image, but also prevent a splash screen or a blue screen on the projection apparatus. 
     For example, the main control circuit  50  may be configured to send the first image signal to the display driving circuit  20  in response to the turn-on command, and the main control circuit  50  may further be configured to send the first image signal to the display driving circuit  20  in response to the standby command. When the main control circuit  50  is configured to send the first image signal to the display driving circuit  20  in response to the standby command, if the main control circuit  50  receives the turn-on command, the display driving circuit  20  will control the display component to be turned on after being powered on, and the display component may display the image corresponding to the first image signal after being turned on. That is to say, the main control circuit  50  may send the first image signal to the display driving circuit  20  when receiving the standby command, and may also send the first image signal to the display driving circuit  20  when receiving the turn-on command. In the following embodiments, the description is made by considering an example where the main control circuit  50  is configured to send the first image signal to the display driving circuit  20  in response to the turn-on command. 
     In some embodiments, the main control circuit  50  is configured to send the first image signal to the at least one light valve driving sub-circuit  23  in response to the turn-on command. The at least one light valve driving sub-circuit  23  is configured to receive the first image signal and control operation of the light valve  1240 , and the light valve  1240  is configured to modulate the illumination beams irradiated on its surface into the projection beams and reflect the projection beams to the projection screen  200 , thereby achieving display of the first image. 
     In some embodiments, the main control circuit  50  is configured to send the first image signal to the image processing sub-circuit  24  in response to the turn-on command. The image processing sub-circuit  24  is configured to decode image data corresponding to the first image signal, and send the decoded image data to the light valve driving sub-circuit  23 . The light valve driving sub-circuit  23  is configured to control operation of the light valve  1240  according to the decoded image data, and the light valve  1240  is configured to modulate the illumination beams irradiating its surface into the projection beams and reflect the projection beams to the projection screen  200 , thereby achieving display of an image corresponding to the first image signal. 
     In some embodiments, the main control circuit  50  is configured to send the first image signal to the display driving circuit  20  in response to the standby command. It will be noted that a manner in which the main control circuit  50  sends the first image signal to the display driving circuit  20  in response to the standby command is the same as a manner in which the main control circuit  50  sends the first image signal to the display driving circuit  20  in response to the turn-on command, which will not be repeated here. 
     The main control circuit  50  is further configured to send the second image signal to the display driving circuit  20 , and send an audio signal corresponding to the second image signal to the audio playback component  30 . An image (a second image) corresponding to the second image signal is an image displayed by the display component  40  when the main control circuit  50  receives the above-mentioned standby command. The display driving circuit  20  is configured to receive the second image signal and control the display component  40  to display the image corresponding to the second image signal. The audio playback component is configured to receive the audio signal corresponding to the second image signal, and play audio corresponding to the audio signal. 
     As shown in  FIG. 6 , the audio playback component  30  includes a power amplifier circuit  31  and a player  32 . The player  32  may be a speaker. The main control circuit  50  is further configured to send the audio signal corresponding to the second image signal to the power amplifier circuit  31 , and the power amplifier circuit  31  is configured to control the player  32  to play the audio corresponding to the audio signal. 
     In some embodiments, the main control circuit  50  is further configured to send the second image signal to the display driving circuit  20 , and send the audio signal corresponding to the second image signal to the audio playback component  30 , in a case where it is determined that the display component  40  is in an ON state. Therefore, the main control circuit sends the second image signal to the display driving circuit  20 , and sends the audio signal corresponding to the second image signal to the audio playback component  30  in the case where display component is in the ON state, which can ensure that the image displayed by the display component is synchronized with the audio played by the audio playback component. 
     For example, the main control circuit  50  is further configured to obtain an indication value for indicating whether the display component  40  is in the ON state from the display driving circuit  20 , and determine that the display component  40  is in the ON state in a case where the indication value is a target value. 
     For example, considering an example where when the indication value is 1, it indicates that the display component  40  is in the ON state, the main control circuit  50  may obtain the indication value from a register of the display driving sub-circuit  21 . When the indication value is 1, the main control circuit  50  determines that the display component  40  is in the ON state. 
     For example, the main control circuit  50  is further configured to receive a start-up completion command from the display driving circuit  20  and determine that the display component  40  is in the ON state. 
     For example, as shown in  FIG. 6 , after the laser arrays  1110 ,  1120 ,  1130  and the light valve  1240  are turned on, the display driving sub-circuit  21  is configured to send a start-up completion command to the main control circuit  50 , and the main control circuit  50  is configured to receive the start-up completion command and determine that the display component  40  is in the ON state. 
     In some embodiments of the present disclosure, after the main control circuit receives the turn-on command, and before the main control circuit sends the second image displayed at time the standby command is received and corresponding audio to the display driving circuit and the audio playback component respectively, a black first image is sent to the display driving circuit. Thus, when the audio playback component plays audio, the display component has already been turned on, so that the second image displayed by the display component may be synchronized with the audio corresponding to the second image played by the audio playback component. 
     In some embodiments, the main control circuit  50  may not send the first image signal to the display driving circuit before sending the second image signal and the audio signal corresponding to the second image signal to the display driving circuit  20  and the audio playback component  30  respectively. Instead, the main control circuit  50  sends the second image signal to the display driving circuit  20  and the audio signal corresponding to the second image signal to the audio playback component  30  after sending the power-on command to the power supply  10  and determining that the display component  40  is in the ON state. In this way, it may also be possible to ensure that the display component has already been turned on before the audio playback component plays audio, which ensures that the second image displayed by the display component can be synchronized with the audio corresponding to the second image played by the audio playback component. 
     Some embodiments of the present disclosure further provide a projection method of a projection apparatus, and the projection apparatus may be any of the above-mentioned projection apparatuses. As shown in  FIG. 7 , the projection method may include steps  701  to  711 . 
     In step  701 , when the display component displays a second image, the main control circuit  50  receives a standby command. 
     In step  702 , the main control circuit  50  sends a power-off command to the power supply  10  in response to the standby command. 
     In some embodiments, the main control circuit  50  may first send a shutdown command to the display driving circuit  20  before sending the power-off command to the power supply  10 . After the display driving circuit  20  receives the shutdown command and turns off the display component in response to the shutdown command, the power supply  10  stops supplying power to the display driving circuit  20 . 
     In step  703 , the power supply  10  receives the power-off command and stops supplying power to the display driving circuit  20  in response to the power-off command. 
     In step  704 , the main control circuit  50  receives a turn-on command. 
     In step  705 , the main control circuit  50  sends a power-on command to the power supply  10  in response to the turn-on command. 
     In step  706 , the power supply  10  receives the power-on command and supplies power to the display driving circuit  20  in response to the power-on command. 
     In some embodiments, the display driving circuit  20  controls the display component to be turned on after being powered on, and sends a start-up completion command for instructing that the display component is turned on to the main control circuit  50 . 
     In step  707 , the main control circuit  50  sends a first image signal to the display driving circuit  20 . 
     In some embodiments, the main control circuit  50  may send the first image signal to the display driving circuit  20  in response to the turn-on command. 
     In some embodiments, the main control circuit  50  may send the first image signal to the display driving circuit  20  in response to the standby command. 
     In step  708 , the display driving circuit  20  receives the first image signal and controls the display component to display an image corresponding to the first image signal. 
     In step  709 , the main control circuit  50  sends a second image signal to the display driving circuit  20 , and sends an audio signal corresponding to the second image signal to the audio playback component  30 . 
     In some embodiments, an image corresponding to the second image signal is an image displayed by the display component when the main control circuit  50  receives the standby command. 
     In step  710 , the display driving circuit  20  receives the second image signal, and controls the display component to display an image corresponding to the second image signal. 
     In step  711 , the audio playback component  30  is configured to receive the audio signal corresponding to the second image signal, and play audio corresponding to the audio signal. 
     It will be noted that some embodiments of the present disclosure do not limit an execution sequence of the foregoing steps  701  to  711 , and  FIG. 7  is an exemplary diagram. For example, step  707  may be performed after step  704 , or may be performed after step  701  and before step  704 . For another example, step  705  and step  707  may be performed simultaneously. 
     In some embodiments of the present disclosure, after the main control circuit  50  receives the turn-on command, and before the main control circuit  50  sends the second image displayed at time the standby command is received to the display driving circuit  20  and corresponding audio to the audio playback component  30 , a first image (e.g., the first image is a black image) is sent to the display driving circuit  20 . Thus, the display component has already been turned on when the audio playback component  30  plays audio, so that the second image displayed by the display component may be synchronized with the audio corresponding to the second image played by the audio playback component  30 . 
     In order to further ensure that the second image displayed by the display component may be synchronized with the audio corresponding to the second image played by the audio playback component, some embodiments of the present disclosure further provide a projection method of a projection apparatus, and the projection apparatus may be any of the above-mentioned projection apparatuses. As shown in  FIG. 8 , the projection method includes steps  801  to  811 . 
     In step  801 , when the display component displays a second image, the main control circuit  50  receives a standby command. 
     In step  802 , the main control circuit  50  sends a power-off command to the power supply  10  in response to the standby command. 
     In some embodiments, the main control circuit  50  may send a shutdown command to the display driving circuit  20  before sending the power-off command to the power supply  10 . The display driving circuit  20  receives the shutdown command and turns off the display component in response to the shutdown command. 
     In step  803 , the power supply  10  receives the power-off command and stops supplying power to the display driving circuit  20  in response to the power-off command. 
     In step  804 , the main control circuit  50  receives a turn-on command. 
     In step  805 , the main control circuit  50  sends a power-on command to the power supply  10  in response to the turn-on command. 
     In step  806 , the power supply  10  receives the power-on command and supplies power to the display driving circuit  20  in response to the power-on command. 
     In some embodiments, the display driving circuit  20  controls the display component to be turned on after being powered on, and sends a start-up completion command for instructing that the display component is turned on to the main control circuit  50 . 
     In step  807 , the main control circuit  50  sends a first image signal to the display driving circuit  20 . 
     In some embodiments, the main control circuit  50  may send the first image signal to the display driving circuit  20  in response to the turn-on command. 
     In some embodiments, the main control circuit  50  may send the first image signal to the display driving circuit  20  in response to the standby command. 
     In step  808 , the display driving circuit  20  receives the first image signal and controls the display component to display an image corresponding to the first image signal. 
     In step  809 , the main control circuit  50  determines that the display component is in an ON state. 
     For example, the main control circuit  50  obtains an indication value for indicating whether the display component is in the ON state from the display driving circuit  20 , and determines that the display component is in the ON state in a case where the indication value is a target value. 
     For example, the main control circuit  50  may further receive a start-up completion command from the display driving circuit  20 , and determine that the display component is in the ON state. 
     In step  810 , the main control circuit  50  sends a second image signal to the display driving circuit  20 , and sends an audio signal corresponding to the second image signal to the audio playback component  30 . 
     In step  811 , the display driving circuit  20  receives the second image signal, and controls the display component to display an image corresponding to the second image signal. 
     In step  812 , the audio playback component  30  is configured to receive the audio signal corresponding to the second image signal, and play audio corresponding to the audio signal. 
     The embodiments of the present disclosure do not limit an execution sequence of the foregoing steps  801  to  812 . For example, step  805  and step  807  may be performed simultaneously, and step  808  and step  809  may be performed simultaneously. 
     In some embodiments of the present disclosure, in a case where the display component is in the ON state, the main control circuit  50  sends the second image signal to the display driving circuit  20  and the audio signal corresponding to the second image signal to the audio playback component  30 , which may further ensure that an image displayed by the display component is synchronized with audio played by the audio playback component  30 . 
     Some embodiments of the present disclosure further provide another projection method of a projection apparatus, and the projection apparatus may be any of the above-mentioned projection apparatuses. As shown in  FIG. 9 , the projection method may include steps  901  to  910 . 
     In step  901 , when the display component displays a second image, the main control circuit  50  receives a standby command. 
     In step  902 , the main control circuit  50  sends a power-off command to the power supply  10  in response to the standby command. 
     In step  903 , the power supply  10  receives the power-off command and stops supplying power to the display driving circuit  20  in response to the power-off command. 
     In step  904 , the main control circuit  50  receives a turn-on command. 
     In step  905 , the main control circuit  50  sends a power-on command to the power supply  10  in response to the turn-on command. 
     In step  906 , the power supply  10  receives the power-on command and supplies power to the display driving circuit  20  in response to the power-on command. 
     In step  907 , the main control circuit  50  determines that the display component is in an ON state. 
     A manner in which the main control circuit  50  determines whether the display component is in the ON state here is the same as that in step  809 , which will not be repeated here. 
     In step  908 , the main control circuit  50  sends a second image signal to the display driving circuit  20 , and sends an audio signal corresponding to the second image signal to the audio playback component  30 . 
     In step  909 , the display driving circuit  20  receives the second image signal, and controls the display component to display an image corresponding to the second image signal. 
     In step  910 , the audio playback component  30  is configured to receive the audio signal corresponding to the second image signal, and play audio corresponding to the audio signal. 
     The embodiments of the present disclosure do not limit an execution sequence of the foregoing steps  901  to  910 . For example, step  905  and step  907  may be performed simultaneously. 
     In some embodiments of the present disclosure, before sending the second image signal to the display driving circuit  20  and the audio signal corresponding to the second image signal to the audio playback component  30 , the main control circuit  50  may not send the first image signal to the display driving circuit  20 . Instead, the main control circuit  50  sends the second image signal to the display driving circuit  20  and the audio signal corresponding to the second image signal to the audio playback component  30  after sending the power-on command to the power supply  10  and determining that the display component  40  is in the ON state. In this way, it may also be possible to ensure that the display component has already been turned on before the audio playback component plays audio, which ensures that the second image displayed by the display component can be synchronized with the audio corresponding to the second image played by the audio playback component. 
     Some embodiments of the present disclosure provide a computer-readable storage medium (e.g., a non-transitory computer-readable storage medium). The computer-readable storage medium stores computer program instructions that, when executed by a projection apparatus, cause the projection apparatus to perform one or more steps in the projection method of the projection apparatus described in any of the foregoing embodiments. 
     Some embodiments of the present disclosure provide a computer program product stored on a non-transitory computer-readable storage medium, and the computer program product includes computer program instructions that cause a computer (e.g., a projection apparatus) to perform the projection method of the projection apparatus shown in any of the embodiments of  FIGS. 7 to 9 . 
     For example, the computer-readable storage medium may include, but is not limited to: a magnetic storage device (e.g., a hard disk, a floppy disk, or a magnetic tape), an optical disk (e.g., a compact disk (CD)), a digital versatile disk (DVD), a smart card and a flash memory device (e.g., an erasable programmable read-only memory (EPROM), a card, a stick or a key drive). The various computer-readable storage media described in the present disclosure may represent one or more devices and/or other machine-readable storage media for storing information. The term “machine-readable storage media” may include, but are not limited to, wireless channels and various other media capable of storing, containing, and/or carrying instruction(s) and/or data. 
     The foregoing descriptions are merely specific implementations of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or replacements that a person skilled in the art could readily conceive of within the technical scope of the present disclosure shall be included in the protection scope of the present disclosure. Therefore, the scope of the present disclosure shall be subject to the protection scope of the claims.