Projection equipment and projection screen lifting control method thereof

Abstract

The present application discloses a projection device and a method for controlling the lifting of a projection screen thereof, and belongs to the field of projection display. A signal detector in the projection device can send a first detection signal to a control component upon detecting the presence of a foreign object at the opening of a receiving slot. Upon receiving the first detection signal, the control component can stop providing a lifting drive signal to the screen drive component. Since the present application can stop providing a lifting drive signal to the screen drive component upon detecting the presence of a foreign object at the opening of the receiving slot, this avoids the situation where the projection screen is blocked by the foreign object when it is rising, thereby improving the reliability of the projection screen lifting control.

Description

Technical Field

[0001] The present disclosure relates to the field of projection display, and in particular to a projection device and a method for controlling the lifting and lowering of a projection screen thereof. Background Art

[0002] Currently, the projection screen and the main unit of the projection device can be an integrated structure. The main unit of the projection device is provided with a receiving slot, and the receiving slot is provided with a screen driving assembly, which is connected to the projection screen and is used to drive the projection screen to rise or fall.

[0003] However, if there is a foreign object at the opening of the receiving groove, the projection screen will be blocked by the foreign object when it is rising and cannot be raised, or the projection screen will be blocked by the foreign object when it is lowered and cannot be retracted into the receiving groove, resulting in low reliability of the projection screen lifting and lowering control. Summary of the Invention

[0004] The present disclosure provides a projection device and a method for controlling the lifting of a projection screen, which can solve the problem of low reliability of the lifting control of the projection screen in related technologies. The technical solution is as follows:

[0005] In one aspect, a projection device is provided, comprising: a housing, a signal detector, a projection screen, a screen drive assembly, and a control assembly located within the housing;

[0006] A receiving groove for receiving the projection screen is provided on one side of the housing;

[0007] The signal detector is connected to the control component and is used to detect whether there is a foreign object at the opening of the receiving slot in response to a power-on instruction, and when it is detected that there is a foreign object at the opening of the receiving slot, send a first detection signal to the control component, and when it is detected that there is no foreign object at the opening of the receiving slot, send a second detection signal to the control component;

[0008] The control component is further connected to the screen drive component, and is configured to stop providing the rising drive signal to the screen drive component when receiving the first detection signal, and provide the rising drive signal to the screen drive component when receiving the second detection signal;

[0009] The screen driving group is connected to the projection screen and is used to control the projection screen to rise out of the accommodating slot under the control of the rising driving signal.

[0010] In another aspect, a projection device is provided, comprising: a housing, a signal detector, a projection screen, a screen drive assembly, and a control assembly located within the housing;

[0011] A receiving groove for receiving the projection screen is provided on one side of the housing;

[0012] The signal detector is connected to the control component and is configured to detect whether there is a foreign object at the opening of the receiving slot in response to a power-off instruction or when the projection screen has descended a distance greater than a third distance threshold, and to send a fifth detection signal to the control component when a foreign object is detected at the opening of the receiving slot, and to send a sixth detection signal to the control component when no foreign object is detected at the opening of the receiving slot;

[0013] The control component is further connected to the screen driving component, and is configured to stop providing the descending driving signal to the screen driving component when receiving the fifth detection signal, and provide the descending driving signal to the screen driving component when receiving the sixth detection signal;

[0014] The screen driving group is connected to the projection screen and is used to control the projection screen to retract into the accommodating slot under the control of the descending driving signal.

[0015] In another aspect, a projection device is provided, comprising: a housing, a signal detector, a projection screen, a screen drive assembly, and a control assembly located in the housing;

[0016] A receiving groove for receiving the projection screen is provided on one side of the housing;

[0017] The signal detector is connected to the control component and is configured to detect whether there is a foreign object at the opening of the receiving slot in response to a power-off instruction or when the projection screen has descended a distance greater than a third distance threshold, and to send a fifth detection signal to the control component when a foreign object is detected at the opening of the receiving slot, and to send a sixth detection signal to the control component when no foreign object is detected at the opening of the receiving slot;

[0018] The control component is further connected to the screen driving component, and is configured to stop providing the descending driving signal to the screen driving component when receiving the fifth detection signal, and provide the descending driving signal to the screen driving component when receiving the sixth detection signal;

[0019] The screen drive group is connected to the projection screen and is used to control the projection screen to retract into the receiving slot under the control of the descending drive signal;

[0020] The control component is further configured to increase the frequency of the descending drive signal provided to the screen drive component when the descending distance of the projection screen exceeds a fourth distance threshold during the process of controlling the projection screen to retract into the accommodating slot;

[0021] The fourth distance threshold is greater than the third distance threshold, and the moving speed of the projection screen is positively correlated with the frequency.

[0022] In another aspect, a method for controlling the raising and lowering of a projection screen is provided. The method is applied to a control assembly located within a housing of a projection device, wherein the projection device further comprises: a signal detector, a projection screen, and a screen drive assembly; a receiving slot for accommodating the projection screen is provided on one side of the housing; the control assembly is connected to the signal detector and the screen drive assembly, respectively, and the screen drive assembly is connected to the projection screen; the method comprises:

[0023] When receiving the first detection signal sent by the signal detector, stopping providing the rising drive signal to the screen driving component;

[0024] When receiving the second detection signal sent by the signal detector, providing an ascending drive signal to the screen drive assembly, wherein the ascending drive signal is used to control the screen drive assembly to control the projection screen to ascend from the receiving slot;

[0025] Among them, the first detection signal is that the signal detector responds to the power-on instruction to detect whether there is a foreign object at the opening of the receiving slot, and when the foreign object is detected at the opening of the receiving slot, the signal detector sends it to the control component; the second detection signal is that the signal detector responds to the power-on instruction to detect whether there is a foreign object at the opening of the receiving slot, and when the foreign object is detected at the opening of the receiving slot, the signal detector sends it to the control component.

[0026] In another aspect, a method for controlling the raising and lowering of a projection screen is provided, the method being applied to a control assembly located within a housing of a projection device, the projection device further comprising: a signal detector, a projection screen, and a screen drive assembly; a receiving slot for accommodating the projection screen being provided on one side of the housing; the control assembly being connected to the signal detector and the screen drive assembly, respectively, and the screen drive assembly being connected to the projection screen; the method comprising:

[0027] When receiving the fifth detection signal sent by the signal detector, stopping providing the descending drive signal to the screen driving assembly;

[0028] When receiving the sixth detection signal sent by the signal detector, a descending drive signal is provided to the screen drive assembly, wherein the descending drive signal is used to control the screen drive assembly to control the projection screen to retract into the receiving slot;

[0029] The fifth detection signal is sent to the control component by the signal detector when the signal detector detects whether there is a foreign object at the opening of the accommodating slot in response to a shutdown instruction or when the descending distance of the projection screen is greater than a third distance threshold, and the sixth detection signal is sent to the control component ... that there is no foreign object at the opening of the accommodating slot.

[0030] In another aspect, a projection device is provided, which is applied to a control assembly located within a housing of the projection device. The projection device further comprises: a signal detector, a projection screen, and a screen drive assembly. A receiving slot for receiving the projection screen is provided on one side of the housing. The control assembly is connected to the signal detector and the screen drive assembly, respectively, and the screen drive assembly is connected to the projection screen. The method comprises:

[0031] When receiving the fifth detection signal sent by the signal detector, stopping providing the descending drive signal to the screen driving assembly;

[0032] When receiving the sixth detection signal sent by the signal detector, a descending drive signal is provided to the screen drive assembly, wherein the descending drive signal is used to control the screen drive assembly to control the projection screen to retract into the receiving slot;

[0033] In the process of controlling the projection screen to retract into the receiving slot, when the descending distance of the projection screen is greater than a fourth distance threshold, increasing the frequency of the descending drive signal provided to the screen drive assembly;

[0034] The fifth detection signal is sent to the control component by the signal detector when the signal detector detects whether a foreign object is present at the opening of the accommodating slot in response to a shutdown instruction or when the descending distance of the projection screen is greater than a third distance threshold, and the sixth detection signal is sent to the control component when the signal detector detects whether a foreign object is present at the opening of the accommodating slot in response to a shutdown instruction or when the descending distance of the projection screen is greater than a third distance threshold, and the fourth distance threshold is greater than the third distance threshold. The moving speed of the projection screen is positively correlated with the frequency.

[0035] The beneficial effects of the technical solutions provided by the embodiments of the present disclosure include at least:

[0036] The disclosed embodiments provide a projection device and a method for controlling the raising and lowering of a projection screen therein. A signal detector in the projection device can, in response to a power-on command, detect the presence of a foreign object at the opening of a receiving slot. Upon detecting the presence of a foreign object at the opening of the receiving slot, the signal detector sends a first detection signal to a control component. Upon receiving the first detection signal, the control component can stop providing an upward drive signal to the screen drive component. This prevents the projection screen from being blocked from rising by the foreign object when the foreign object is present at the opening of the receiving slot, thereby improving the reliability of the projection screen raising control. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0038] Figure 1 is a structural schematic diagram of a projection device provided by an embodiment of the present disclosure;

[0039] Figure 2 is a structural diagram of another projection device provided by an embodiment of the present disclosure;

[0040] Figure 3 is a structural diagram of another projection device provided by an embodiment of the present disclosure;

[0041] Figure 4 is a structural diagram of a signal detector provided by an embodiment of the present disclosure;

[0042] Figure 5 is a structural diagram of another projection device provided by an embodiment of the present disclosure;

[0043] Figure 6 is a structural diagram of another projection device provided by an embodiment of the present disclosure;

[0044] Figure 7 is a structural diagram of another projection device provided by an embodiment of the present disclosure;

[0045] Figure 8 is a structural diagram of another projection device provided by an embodiment of the present disclosure;

[0046] Figure 9 is a structural diagram of another projection device provided by an embodiment of the present disclosure;

[0047] Figure 10 is a structural diagram of another projection device provided by an embodiment of the present disclosure;

[0048] Figure 11 is a structural diagram of another projection device provided by an embodiment of the present disclosure;

[0049] Figure 12 is a structural schematic diagram of a shielding rod provided by an embodiment of the present disclosure;

[0050] Figure 13 is a structural diagram of another projection device provided by an embodiment of the present disclosure;

[0051] Figure 14 is a schematic diagram of a pulse signal sequence provided by an embodiment of the present disclosure;

[0052] Figure 15 is a schematic diagram of another pulse signal sequence provided by an embodiment of the present disclosure;

[0053] Figure 16 This is a flow chart of a method for controlling the lifting of a projection screen provided by an embodiment of the present disclosure;

[0054] Figure 17 This is a flow chart of another method for controlling the lifting of a projection screen provided by an embodiment of the present disclosure;

[0055] Figure 18 This is a flowchart of another method for controlling the lifting of a projection screen provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0056] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0057] Figure 1 It is a structural schematic diagram of a projection device provided by an embodiment of the present disclosure. Figure 2 FIG. 1 is a schematic diagram of another projection device provided by an embodiment of the present disclosure. Figure 1 and Figure 2 As shown, the projection device may include a housing 10, a signal detector 20, a projection screen 30, a screen drive assembly 40, and a control assembly 50 located in the housing 10. Figure 3 As shown, a receiving groove 00 for receiving the projection screen 30 is provided on one side of the housing 10 , and one end of the projection screen 30 can be fixed in the receiving groove 00 .

[0058] refer to Figure 2The signal detector 20 is connected to the control component 50. The signal detector 20 is used to detect whether there is a foreign object at the opening of the receiving slot 00 in response to a power-on command, and when a foreign object is detected at the opening of the receiving slot 00, send a first detection signal to the control component 50. When no foreign object is detected at the opening of the receiving slot 00, send a second detection signal to the control component 50.

[0059] In the embodiment of the present disclosure, upon receiving a power-on command for the projection device, the control component 50 may activate the signal detector 20 and transmit the power-on command to the signal detector 20. In response to the power-on command, the signal detector 20 may detect whether a foreign object is present at the opening of the receiving slot 00. A foreign object is an object that can block the opening of the receiving slot 00. For example, the foreign object may be a cup, a toy, or a user's hand.

[0060] refer to Figure 2 The control component 50 is also connected to the screen driving component 40. The control component 50 is configured to stop providing the rising driving signal to the screen driving component 40 when receiving the first detection signal. The control component 50 provides the rising driving signal to the screen driving component 40 when receiving the second detection signal.

[0061] refer to Figure 2 The screen drive assembly 40 is connected to the projection screen 30. The screen drive assembly 40 is used to control the projection screen 30 to rise from the accommodating slot 00 or retract the accommodating slot 00 under the control of the rising drive signal.

[0062] Example, reference Figure 2 and Figure 3 When the projection device is in the off state, the projection screen 30 is located within the receiving slot 00. Upon receiving a power-on command for the projection device, the control component 50 may activate the signal detector 20 and transmit the power-on command to the signal detector 20. The signal detector 20 may then, in response to the power-on command, detect whether a foreign object is present at the opening of the receiving slot 00. Upon detecting the presence of a foreign object at the opening of the receiving slot 00, the control component 50 may transmit a first detection signal to the control component 50. Upon receiving the first detection signal, the control component 50 may not provide an ascending drive signal to the screen drive component 40, thereby preventing the projection screen from being blocked by foreign objects during its ascending process.

[0063] When the signal detector 20 detects that there is no foreign matter at the opening of the receiving slot 00, it can send a second detection signal to the control component 50. After receiving the second detection signal, the control component 50 can provide an upward driving signal to the screen driving component 40, and the screen driving component 40 can control the projection screen 30 to move upward. Figure 3 The state shown is from the receiving groove 00 rising to Figure 1 Furthermore, the control component 50 may turn off the signal detector 20 after receiving the second detection signal.

[0064] In summary, the disclosed embodiments provide a projection device in which a signal detector is capable of detecting the presence of a foreign object at the opening of a receiving slot in response to a power-on command. Upon detecting the presence of a foreign object at the opening of the receiving slot, a first detection signal is transmitted to a control component. Upon receiving the first detection signal, the control component can stop providing the upward drive signal to the screen drive component. This prevents the projection screen from being blocked from ascending by the foreign object when the foreign object is present at the opening of the receiving slot, thereby improving the reliability of the projection screen's upward control.

[0065] refer to Figure 4 The signal detector 20 may include a signal transmitter 21 and a signal receiver 22. The signal transmitter 21 is used to transmit a detection signal, and the signal receiver 22 is used to receive the detection signal transmitted by the signal transmitter 21. If the signal receiver 22 does not receive the detection signal transmitted by the signal transmitter 21, the signal receiver 22 may determine that a foreign object is present at the opening of the receiving slot 00 and may send a first detection signal to the control component 50. If the signal receiver 22 receives the detection signal transmitted by the signal transmitter 21, the signal receiver 22 may determine that no foreign object is present at the opening of the receiving slot 00 and may send a second detection signal to the control component 50.

[0066] As an optional implementation of the embodiment of the present disclosure, the signal transmitter 21 and the signal receiver 22 are relatively arranged on two sides of the receiving slot 00, wherein the signal detector 20 can be a projected infrared sensor or a projected non-infrared sensor.

[0067] For example, reference Figure 5 The opening of the receiving slot 00 may be a quadrilateral, for example, a rectangle. The signal transmitter 21 and the signal receiver 22 may be relatively arranged on both sides of the long side of the opening of the receiving slot 00, and the signal transmitter 21 transmits the detection signal along the extension direction of the long side of the opening of the receiving slot 00. Alternatively, the signal transmitter 21 and the signal receiver 22 may also be relatively arranged on both sides of the short side of the opening of the receiving slot 00, and the signal transmitter 21 transmits the detection signal along the extension direction of the short side of the opening of the receiving slot 00. If the signal receiver 22 receives the detection signal sent by the signal transmitter 21, the signal receiver 22 may determine that there is no foreign matter at the opening of the receiving slot 00. If the signal receiver 22 cannot receive the detection signal sent by the signal transmitter 21, the signal receiver 22 may determine that there is a foreign matter at the opening of the receiving slot 00.

[0068] As another optional implementation of the embodiment of the present disclosure, the signal transmitter 21 and the signal receiver 22 are both arranged on one side of the receiving slot 00 .

[0069] For example, reference Figure 5 The signal transmitter 21 and the signal receiver 22 may both be disposed on one side of the long side of the opening of the receiving slot 00 . Alternatively, the signal transmitter 21 and the signal receiver 22 may both be disposed on one side of the short side of the opening of the receiving slot 00 .

[0070] Assuming that the signal transmitter 21 and the signal receiver 22 are both disposed on one side of the short side of the opening of the receiving slot 00, if the signal receiver 22 receives the detection signal transmitted by the signal transmitter 21, the signal receiver 22 can determine that a foreign object is present at the opening of the receiving slot 00. That is, the detection signal transmitted by the signal transmitter 21 is reflected by the foreign object and then received by the signal receiver 22. If the signal receiver 22 does not receive the detection signal transmitted by the signal transmitter 21, the signal receiver 22 can determine that no foreign object is present at the opening of the receiving slot 00.

[0071] As another optional implementation of the embodiment of the present disclosure, the signal transmitter 21 and the signal receiver 22 are both arranged in the receiving slot 00. Figure 1 、 Figure 5 、 Figure 6 and Figure 7 The screen drive assembly 40 may include a crossbar assembly 41, which is connected to the projection screen 30. The crossbar assembly 41 has a light-transmitting area 01. The orthographic projection of the signal transmitter 21 on the crossbar assembly 41 and the orthographic projection of the signal receiver 22 on the crossbar assembly 41 are both located in the light-transmitting area 01 of the crossbar assembly 41. As a result, the detection signal emitted by the signal transmitter 21 can pass through the crossbar assembly 41, thereby avoiding the situation where the detection signal emitted by the signal transmitter 21 is blocked by the crossbar assembly 41, resulting in the signal receiver 22 being unable to receive the detection signal and causing a misjudgment, thereby ensuring the reliability of foreign object detection. Among them, the signal detector 20 can be a transmitting infrared sensor or a reflective non-infrared sensor.

[0072] As another optional implementation of the embodiment of the present disclosure, the signal transmitter 21 and the signal receiver 22 can both be disposed on the crossbar assembly 41. Optionally, the crossbar assembly 41 has a light-transmitting area 01, and the orthographic projection of the signal transmitter 21 on the crossbar assembly 41 and the orthographic projection of the signal receiver 22 on the crossbar assembly 41 are both located in the light-transmitting area 01 of the crossbar assembly 41.

[0073] The detection signal emitted by the signal transmitter 21 can pass through the crossbar assembly 41. If the signal receiver 22 receives the detection signal sent by the signal transmitter 21, the signal receiver 22 can determine that there is a foreign object at the opening of the receiving slot 00, that is, the detection signal emitted by the signal transmitter 21 passes through the crossbar assembly 41 and is reflected by the foreign object, and the reflected detection signal passes through the crossbar assembly 41 again and is received by the signal receiver 22.

[0074] As another optional implementation of the embodiment of the present disclosure, one of the signal transmitter 21 and the signal receiver 22 is disposed in the receiving slot 00, and the other is disposed on the crossbar assembly 41. For example, the signal transmitter 21 can be disposed in the receiving slot 00, and the signal receiver 22 can be disposed on the crossbar assembly 41. The crossbar assembly 41 has a light-transmitting area 01, and the orthographic projection of the signal transmitter 21 on the crossbar assembly 41 and the orthographic projection of the signal receiver 22 on the crossbar assembly 41 are both located in the light-transmitting area 01 of the crossbar assembly 41.

[0075] Optionally, the detection signal emitted by the signal transmitter 21 may pass through the crossbar assembly 41. If the signal receiver 22 receives the detection signal sent by the signal transmitter 21, the signal receiver 22 may determine that there is a foreign object at the opening of the receiving slot 00, that is, the detection signal emitted by the signal transmitter 21 passes through the crossbar assembly 41 and is reflected by the foreign object, and the reflected detection signal passes through the crossbar assembly 41 again and is received by the signal receiver 22.

[0076] Therefore, the detection signal emitted by the signal transmitter 21 can pass through the cross bar assembly 41, and the detection signal reflected by the foreign object can also pass through the cross bar assembly 41, thereby avoiding the situation where the detection signal emitted by the signal transmitter 21 and the detection signal reflected by the foreign object are blocked by the cross bar assembly 41, resulting in the signal receiver 22 being unable to receive the detection signal and causing misjudgment, thereby ensuring the reliability of foreign object detection.

[0077] refer to Figure 7 The screen driving assembly 40 may further include a screen driving circuit 42, a motor 43, a lifting rod 44 and a lifting rod driving assembly 45. Optionally, the motor 43 may also be referred to as a motor.

[0078] The screen driving circuit 42 is connected to the control component 50 and the motor 43 respectively. The screen driving circuit 42 is used to provide a first driving current to the motor 43 in response to the rising driving signal.

[0079] The lifting rod driving assembly 45 is connected to the motor 43 and the lifting rod 44 respectively. The motor 43 is used to drive the lifting rod driving assembly 45 to push the lifting rod 44 up under the driving of the first driving current.

[0080] The lifting rod 44 is connected to the crossbar assembly 41 . The lifting rod 44 is used to push the crossbar assembly 41 upward under the push of the lifting rod driving assembly 45 , thereby pushing the projection screen 30 upward.

[0081] refer to Figure 8 The screen drive assembly 40 may include a guide rail 02 disposed in the receiving slot 00, and two drive subassemblies disposed on both sides of the receiving slot 00, each drive subassembly including a screen drive circuit 42 ( Figure 8 (not shown), a motor 43, a lifting rod 44, and a lifting rod drive assembly 45. Each lifting rod drive assembly 45 includes a slider drive subassembly ( Figure 8 ), a slider 450 and a power rod 451. Each lifting rod 44 may include a first rod body 440, a second rod body 441 and an elastic component 442 for connecting the two rod bodies.

[0082] In each drive subassembly, the motor 43 is connected to a corresponding screen drive circuit 42. One end of the first rod 440 is connected to one end of the crossbar assembly 41, and the other end is connected to one end of the second rod 441 via an elastic component 442. The other end of the second rod 441 is connected to the guide rail 02. One end of the power rod 451 is connected to the slider 450, and the other end of the power rod 451 is connected to the side wall of the second rod 441 near the end of the guide rail 02.

[0083] Each motor 43, driven by the first driving current provided by the corresponding screen drive circuit 42, drives each slider driving subassembly to push the corresponding slider 450 to slide along the guide rail 02 toward the side close to the motor 43, thereby pushing the power rod 451 toward the side close to the motor 43. The power rod 451 can then push the first rod 440 upward through the second rod 441, thereby pushing the lifting rod 44 upward.

[0084] refer to Figure 9 The projection device may further include a position detector 60, which may be disposed within the receiving slot 00 and connected to the control assembly 50. The position detector 60 is configured to detect whether the projection screen 30 is in the top position in response to a power-on command. When the projection screen 30 is detected to be in the top position, the position detector 60 sends a third detection signal to the control assembly 50. When the projection screen 30 is detected to be not in the top position, the position detector 60 sends a fourth detection signal to the control assembly 50.

[0085] When the control component 50 receives the third detection signal, it can determine that the projection screen 30 is currently at the top position, and then stop providing the upward drive signal to the screen drive component 40, and provide a hold signal to the screen drive component 40. When the control component 50 receives the fourth detection signal, it can determine that the projection screen 30 has not currently reached the top position, and then provide the upward drive signal to the screen drive component 40.

[0086] The screen driving assembly 40 is used to control the projection screen 30 to remain at the top position under the control of the maintain driving signal, and to control the projection screen 30 to rise under the control of the rise driving signal.

[0087] refer to Figure 9 The projection device may further include a multimedia component 70, which may include an audio and video control circuit 71. The audio and video control circuit 71 is connected to the control component 50. A start button may be provided on the housing 10 of the projection device. When the audio and video control circuit 71 detects a user clicking the start button, it may generate a power-on command and send the power-on command to the control component 50. After receiving the power-on command, the control component 50 may activate the position detector 60 and send the power-on command to the position detector 60. The position detector 60 may then detect whether the projection screen 30 is in the top position in response to the power-on command.

[0088] Alternatively, the power-on command may be triggered by a user via a remote control. After receiving the power-on command from the remote control, the audio and video control circuit 71 may send the power-on command to the control component 50. After receiving the power-on command, the control component 50 may activate the position detector 60 and send the power-on command to the position detector 60. In response to the power-on command, the position detector 60 may detect whether the projection screen 30 is in the top position.

[0089] Optionally, a communication interface may be provided on the multimedia component 70 and the control component 50. The multimedia component 70 and the control component 50 may be connected via the communication interface and transmit a power-on command according to a serial communication protocol. The communication interface may be a standard (recommended standard, RS) 232 communication interface.

[0090] In the disclosed embodiment, while the screen drive assembly 40 is controlling the projection screen 30 to ascend, the position detector 60 can detect in real time whether the projection screen 30 is in the top position. If it detects that the projection screen 30 is not yet in the top position, it can continue to send a fourth detection signal to the control assembly 50. The control assembly 50 then continues to send an ascending drive signal to the screen drive assembly 40, thereby controlling the projection screen 30 to ascend. This cycle continues until the position detector 60 detects that the projection screen 30 is in the top position. At this point, the position detector 60 can send a third detection signal to the control assembly 50. Upon receiving this third detection signal, the control assembly 50 can stop sending the ascending drive signal to the screen drive assembly 40 and provide a hold signal to the screen drive assembly 40. In response to the hold signal, the screen drive assembly 40 can control the projection screen 30 to remain in the top position.

[0091] refer to Figure 10 、 Figure 11 、 Figure 12 and Figure 13 The screen drive assembly 40 may further include a shielding rod 47. The motor 43 includes a rotating shaft 430, and the shielding rod 47 is disposed on the rotating shaft 430. The motor 43 is further configured to drive the shielding rod 47 to rotate under the drive of the first driving current. The shielding rod 47 and the position detector 60 are disposed opposite each other, and the shielding rod 47 shields the position detector 60 during rotation.

[0092] The position detector 60 is further configured to count the number of rotations m of the shielding rod 431 in response to a power-on command. The position detector 60 detects whether the number of rotations m is less than or equal to a threshold number M. If the number of rotations m is equal to the threshold number M, the projection screen 30 is determined to be in the top position. If the number of rotations m is less than the threshold number M, the projection screen 30 is determined to be not in the top position. The threshold number M is a fixed value pre-stored in the position detector 60.

[0093] Optionally, the position detector 60 may include a transmitter and a receiver, wherein the transmitter is configured to transmit a light signal and the receiver is configured to receive the light signal transmitted by the transmitter. If the light path between the transmitter and the receiver is not blocked, the receiver can receive the light signal transmitted by the transmitter, and in this case, the receiver cannot detect a pulse signal. If the light path between the transmitter and the receiver is blocked, the receiver cannot receive the light signal transmitted by the transmitter, and in this case, the receiver can detect a pulse signal.

[0094] refer to Figure 11 、 Figure 12 and Figure 13 The shielding rod 47 may include h shielding parts 470 and a connecting rod 471, one end of the connecting rod 471 is sleeved on the rotating shaft 430, and the other end of the connecting rod 471 is connected to the shielding part 470. For example, Figure 12 The shielding rod 47 is shown to include three shielding portions, namely a first shielding portion 4701 and two second shielding portions 4702. The first shielding portion 4701 is located on one side of the connecting rod 471, and one end of the first shielding portion 4701 is connected to one end of each of the two second shielding portions 4702. The two second shielding portions 4702 are located on the other side of the connecting rod 471, and one end of the two second shielding portions 4702 is also connected. Here, h is a positive integer greater than 0.

[0095] During one rotation of the rotating shaft 430 , the position detector 60 can detect a pulse signal sequence with a period T. In this period T, the h shielding portions 470 sequentially shield the position detector 60 , and the position detector 60 can detect h pulse signals.

[0096] During the process of controlling the projection screen 30 to rise, the screen drive circuit 42, under the control of the rising drive signal provided by the control assembly 50, provides a first drive current to the motor 43. Driven by the first drive current, the rotating shaft 430 of the motor 43 rotates in a first direction, thereby driving the connecting rod 471 to rotate in the first direction, and further driving the shielding portion 470 to rotate in the first direction. The first direction can be clockwise.

[0097] refer to Figure 12 and Figure 14 During one rotation of the rotating shaft 430 in the first direction, the position detector 60 can detect a pulse signal sequence with a period T. Furthermore, within this period T, if the two second blocking portions 4702 sequentially block the position detector 60, the position detector 60 can detect two pulse signals with a short time interval during time period t1. If the first blocking portion 4701 blocks the position detector 60, the position detector 60 can detect a single pulse signal during time period t2.

[0098] In the disclosed embodiment, assume that during the movement of the projection screen 30 from its initial position to its top position, the position detector 60 detects a total of k pulse signals. Since the position detector 60 detects a pulse signal sequence with a period T for each rotation of the rotating shaft 430 in the motor 43, and within this period T, the position detector 60 detects h pulse signals. Therefore, the position detector 60 can calculate the number of rotations of the shielding rod 47 as m, which satisfies the following equation: Here, k is a positive integer greater than 0.

[0099] During the starting process of the motor 43 , if its starting frequency is too high or its load is too heavy, the number of rotations m may be less than the threshold value M.

[0100] Assuming that the motor 43 has a normal starting frequency and a normal load during startup, the motor 43 needs to rotate N step angles, which are θ degrees, during the process of the projection screen 30 moving from the initial position to the top position. The motor 43 rotates 360 degrees in one circle, so it needs to rotate n step angles in one circle. The projection screen 30 moves from the initial position to the top position, and the motor 43 needs to rotate y times. Wherein, N and θ are both greater than 0.

[0101] Since the position detector 60 can detect a pulse signal sequence with a period T for each rotation of the rotating shaft 430 in the motor 43, and in this period T, the position detector 60 can detect h pulse signals. Therefore, when the rotating shaft 430 in the motor 43 rotates y times, the position detector 60 can detect h×y pulse signals. Based on the number of pulse signals detected when the projection screen 30 moves from the initial position to the top position, and the number of pulse signals detected in each period T, the revolution threshold M can be determined. The revolution threshold M is

[0102] For example, assuming N = 480, step angle θ = 7.5°, the motor 43 needs to rotate once Step angle, the projection screen 30 moves from the initial position to the top position, the motor 43 needs to rotate Then the circle number threshold M=y=10.

[0103] Optionally, the control component 50 is further configured to, during each detection cycle while controlling the projection screen 30 to be raised from the receiving slot 00, obtain the distance traveled by the projection screen 30 within the detection cycle. The control component 50 then detects whether the travel distance is greater than a first distance threshold. If the travel distance is greater than the first distance threshold, indicating that the projection screen 20 is moving at a relatively fast speed, the frequency of the rising drive signal provided to the screen drive component 40 may be reduced, thereby reducing the speed of the projection screen 30. If the travel distance is less than or equal to the first distance threshold, the control component 50 detects whether the travel distance is less than a second distance threshold. If the travel distance is less than the second distance threshold, indicating that the projection screen 30 is moving at a relatively slow speed, the frequency of the rising drive signal provided to the screen drive component 40 may be increased, thereby increasing the speed of the projection screen 30.

[0104] The first distance threshold is greater than the second distance threshold, and the moving speed of the projection screen 30 is positively correlated with the frequency. That is, the greater the frequency of the rising drive signal, the faster the moving speed of the projection screen 30; and the smaller the frequency of the rising drive signal, the slower the moving speed of the projection screen 30.

[0105] In the embodiment of the present disclosure, when controlling the projection screen 30 to be lifted out of the receiving slot 00, the moving speed of the projection screen 30 can be dynamically adjusted according to the moving distance of the projection screen 30 within the detection cycle, thereby improving the flexibility of the control over the lifting of the projection screen.

[0106] refer to Figure 9 The projection device may further include a distance detector 80, which is disposed on at least one side of the receiving slot 00. Optionally, a distance sensor 80 is disposed on either side of the long side of the opening of the receiving slot 00. Alternatively, referring to Figure 5 , distance detectors 80 are provided on both sides of the long side of the opening of the receiving slot 00. Optionally, the distance detector 80 can be an infrared sensor or a non-infrared sensor.

[0107] The distance detector 80 is connected to the control assembly 50 . The distance detector 80 is used to transmit an optical signal and receive an optical signal reflected by the crossbar assembly 41 .

[0108] The control component 50 is further configured to determine the moving distance d of the projection screen 30 during the detection period based on the time t3 at which the distance detector 80 transmits the light signal and the time t4 at which the light signal reflected by the crossbar component 41 is received.

[0109] Optionally, the control component 50 pre-stores the transmission speed V of the optical signal. During each detection cycle, the control component 50 can obtain the emission time t3 of the optical signal emitted by the distance detector 80 and the reception time t4 of the optical signal reflected by the crossbar assembly 41. Based on the emission time t3 and the reception time t4 of the optical signal, the control component 50 can determine the transmission duration T1 of the optical signal during the detection cycle. The transmission duration T1 = t4 - t3.

[0110] Afterwards, the control component 50 can determine the moving distance d of the projection screen 30 within the detection cycle according to the transmission speed V and transmission time T1 of the pre-stored optical signal. The moving distance d satisfies:

[0111]

[0112] In the embodiments of the present disclosure, reference Figure 5 If distance detectors 80 are provided on both sides of the long side of the opening of the receiving slot 00, the control component 50 can determine two moving distances based on the two distance detectors 80. The control component 50 can use the average of the two moving distances as the moving distance of the projection screen 30 during the detection cycle.

[0113] refer to Figure 5 and Figure 8Distance detectors 80 are provided on both sides of the long side of the opening of the receiving slot 00. During the process of controlling the projection screen 30 to rise via the two motors 43, the control component 50 determines two moving distances based on the two distance detectors during each detection cycle. The control component 50 can then detect whether the difference between the two moving distances is greater than a difference threshold. If the difference is greater than the difference threshold, it indicates that the difference in moving distance between the two sides of the projection screen 30 is significant. Therefore, the frequency of the rising drive signal provided to either screen drive circuit 42 can be adjusted to ensure that the difference in moving distance between the two sides of the projection screen 30 remains within a constant range. If the difference is less than or equal to the difference threshold, it indicates that the difference in moving distance between the two sides of the projection screen 30 is small, and there is no need to adjust the frequency of the rising drive signal provided to the two screen drive circuits 42.

[0114] Optionally, when adjusting the frequency of the rising drive signal provided to any one of the screen drive circuits 42, the control component 50 may reduce the frequency of the rising drive signal provided to one screen drive circuit 42, thereby reducing the movement speed of one side of the projection screen 30. Alternatively, the control component 50 may increase the frequency of the rising drive signal provided to the other screen drive circuit 42, thereby increasing the movement speed of the other side of the projection screen 30.

[0115] The one screen driving circuit 42 is the screen driving circuit that drives one side of the projection screen 30 to move a larger distance during the detection period. The other screen driving circuit 42 is the screen driving circuit that drives the other side of the projection screen 30 to move a smaller distance during the detection period.

[0116] In summary, the disclosed embodiments provide a projection device in which a signal detector can transmit a first detection signal to a control assembly upon detecting the presence of a foreign object at the opening of a receiving slot. Upon receiving this first detection signal, the control assembly can stop providing the upward drive signal to the screen drive assembly. This prevents the projection screen from being blocked from ascending by the foreign object when the foreign object is present at the opening of the receiving slot, thereby improving the reliability of the projection screen's upward control.

[0117] In the embodiments of the present disclosure, reference Figure 2 The signal detector 20 is further configured to detect whether there is a foreign object at the opening of the receiving slot 00 in response to a power-off command or when the projection screen 30 descends a distance greater than a third distance threshold, and to send a fifth detection signal to the control component 50 when a foreign object is detected at the opening of the receiving slot 00. When no foreign object is detected at the opening of the receiving slot 00, a sixth detection signal is sent to the control component 50.

[0118] In the embodiment of the present disclosure, after receiving a shutdown command for the projection device, the control component 50 can start the signal detector 20 and send the shutdown command to the signal detector 20. The signal detector 20 can detect whether there is a foreign object at the opening of the receiving slot 00 in response to the shutdown command.

[0119] Alternatively, while controlling the projection screen 30 to retract into the receiving slot 00, the control component 50 can obtain the distance the projection screen 30 has descended in real time and detect whether the distance is greater than a third distance threshold. If the distance is greater than the third distance threshold, it can be determined that the projection screen 30 has descended into the detection range of the signal detector 20. The control component 50 can activate the signal detector 20, which can detect whether a foreign object is present at the opening of the receiving slot 00. The third distance threshold is a fixed value pre-stored in the control component 50.

[0120] refer to Figure 2 The control component 50 is further configured to stop providing the descending drive signal to the screen driving component 40 when the fifth detection signal is received. The control component 50 is configured to provide the descending drive signal to the screen driving component 40 when the sixth detection signal is received.

[0121] refer to Figure 2 The screen driving assembly 40 is connected to the projection screen 30 and is used to control the projection screen 30 to retract into the receiving slot 00 under the control of the descending driving signal.

[0122] refer to Figure 1 and Figure 2 When the projection device is turned on, the projection screen 30 is in the open state. After receiving a shutdown command for the projection device, the control component 50 can re-enable the signal detector 20. The signal detector 20 can then detect whether there is a foreign object at the opening of the receiving slot 00. Upon detecting the presence of a foreign object at the opening of the receiving slot 00, the control component 50 sends a fifth detection signal to the control component 50. Upon receiving the fifth detection signal, the control component 50 stops providing the descending drive signal to the screen drive component 40, thereby preventing the projection screen from being blocked by foreign objects during its descent and unable to retract into the receiving slot 00.

[0123] When the signal detector 20 detects that there is no foreign matter in the receiving slot 00, the signal detector 20 can send a sixth detection signal to the control component 50. After receiving the sixth detection signal, the control component 50 provides a descending drive signal to the screen drive component 40, thereby controlling the projection screen 30 to move downward. Figure 1 In the state shown, the receiving slot 00 is retracted.

[0124] In summary, the embodiments of the present disclosure provide a projection device in which a signal detector is capable of detecting the presence of a foreign object at the opening of the receiving slot in response to a shutdown command or when the projection screen has descended a distance greater than a third distance threshold. When the presence of a foreign object at the opening of the receiving slot is detected, a fifth detection signal is sent to the control component. Upon receiving the fifth detection signal, the control component can stop providing a descending drive signal to the screen drive component. This prevents the projection screen from being blocked from descending by a foreign object at the opening of the receiving slot, thereby improving the reliability of the projection screen's descending control.

[0125] refer to Figure 4 The signal detector 20 may include a signal transmitter 21 and a signal receiver 22. The signal transmitter 21 and the signal receiver 22 are disposed on opposite sides of the receiving slot 00. Alternatively, the signal transmitter 21 and the signal receiver 22 are both disposed on one side of the receiving slot 00. Alternatively, the signal transmitter 21 and the signal receiver 22 are both disposed within the receiving slot 00.

[0126] Alternatively, the signal transmitter 21 and the signal receiver 22 may both be disposed on the crossbar assembly 41 .

[0127] Alternatively, one of the signal transmitter 21 and the signal receiver 22 is disposed within the receiving slot 00, and the other is disposed on the crossbar assembly 41. Optionally, the detection signal emitted by the signal transmitter 21 can pass through the crossbar assembly 41. If the signal receiver 22 receives the detection signal emitted by the signal transmitter 21, the signal receiver 22 can determine that no foreign object is present at the opening of the receiving slot 00. If the signal receiver 22 cannot receive the detection signal emitted by the signal transmitter 21, the signal receiver 22 can determine that a foreign object is present at the opening of the receiving slot 00.

[0128] refer to Figure 7 The screen drive circuit 42 is further configured to provide a second drive current to the motor 43 in response to the descending drive signal. Driven by the second drive current, the motor 43 drives the lift rod drive assembly 45 to pull the lift rod 44 downward. The lift rod 44 is also configured to pull the crossbar assembly 41 downward, thereby pulling the projection screen 30 downward, driven by the lift rod drive assembly 45.

[0129] refer to Figure 8 Each motor 43, driven by the second driving current provided by the corresponding screen drive circuit 42, drives each slider driving subassembly to push the corresponding slider 450 to slide along the guide rail 02 toward the side away from the motor 43, thereby pushing the power rod 451 to move toward the side away from the motor 43. The power rod 451 can then pull the first rod 440 downward through the second rod 441, thereby pulling the lifting rod 44 downward.

[0130] refer to Figure 9 The position detector 60 is further configured to detect, in response to a shutdown instruction, whether the projection screen 30 is in the initial position, and to send a seventh detection signal to the control component 50 when detecting that the projection screen 30 is in the initial position, and to send an eighth detection signal to the control component 50 when detecting that the projection screen 30 is not in the initial position.

[0131] The control component 50 is configured to, upon receiving the seventh detection signal, determine that the projection screen 30 is currently in the initial position and stop providing the downward drive signal to the screen drive component 40. Upon receiving the eighth detection signal, it is configured to determine that the projection screen 30 is currently not in the initial position and, therefore, send the downward drive signal to the screen drive component 40.

[0132] The screen driving assembly 40 is further used to control the projection screen 30 to descend under the control of the descending driving signal.

[0133] Optionally, a shutdown button may be provided on the housing 10 of the projection device. Figure 9 When the audio and video control circuit 71 detects that the user clicks the shutdown button, it can generate a shutdown command and send the shutdown command to the control component 50. After receiving the shutdown command, the control component 50 can start the position detector 60 and send the shutdown command to the position detector 60. In response to the shutdown command, the position detector 60 detects whether the projection screen 30 is in the initial position.

[0134] Alternatively, the shutdown command may be triggered by a user via a remote control. After receiving the shutdown command from the remote control, the audio and video control circuit 71 may send the shutdown command to the control component 50. After receiving the shutdown command, the control component 50 may activate the position detector 60 and send the shutdown command to the position detector 60. The position detector 60 may detect whether the projection screen 30 is in the initial position in response to the shutdown command.

[0135] In the disclosed embodiment, while the screen drive assembly 40 is controlling the projection screen 30 to descend, the position detector 60 can detect in real time whether the projection screen 30 is in its initial position. If it detects that the projection screen 30 is not in its initial position, the position detector 60 can continue to send an eighth detection signal to the control assembly 50. Upon receiving the eighth detection signal, the control assembly 50 can determine that the projection screen 30 is not in its initial position and can continue to send a descending drive signal to the screen drive assembly 40 to control the projection screen 30 to descend. This cycle continues until the position detector 60 detects that the projection screen 30 is in its initial position and sends a fifth detection signal to the control assembly 50. Upon receiving the seventh detection signal, the control assembly 50 stops providing the descending drive signal to the screen drive assembly 40.

[0136] In the disclosed embodiment, the position detector 60 is further configured to, in response to a shutdown command, count the number m of rotations of the shielding rod 431 within a fixed period. The position detector 60 then detects whether the number m is less than or equal to a threshold number M. If the number m is equal to the threshold number M, the projection screen 30 is determined to be in the initial position. If the number m is less than the threshold number M, the projection screen 30 is determined to be not in the initial position.

[0137] During the process of controlling the projection screen 30 to descend, the screen drive circuit 42, under the control of the descending drive signal provided by the control assembly 50, provides a second drive current to the motor 43. Driven by the second drive current, the rotating shaft 430 of the motor 43 rotates in the second direction, thereby driving the connecting rod 471 to rotate in the second direction, and further driving the shielding portion 470 to rotate in the second direction. The second direction can be counterclockwise.

[0138] refer to Figure 12 and Figure 15 During one rotation of the rotating shaft 430 in the second direction, the position detector 60 can detect a pulse signal sequence with a period T. Furthermore, within this period T, if the first blocking portion 4701 blocks the position detector 60, the position detector 60 can detect a pulse signal during time period t5. If the two second blocking portions 4702 block the position detector 60 in sequence, the position detector 60 can detect two pulse signals with a shorter time interval in sequence during time period t6.

[0139] Optionally, when controlling the projection screen 30 to move from the top position to the initial position, the calculation method of the circle threshold M and the rotation circle m can refer to the calculation method of the circle threshold M and the rotation circle m when controlling the projection screen 30 to move from the initial position to the top position.

[0140] Optionally, the control component 50 is further configured to obtain a descending distance of the projection screen 30 while controlling the projection screen 30 to retract into the receiving slot 00. If the descending distance is greater than a fourth distance threshold, the signal detector 20 is turned off and the frequency of the descending drive signal provided to the screen drive component 40 is increased.

[0141] The descending distance refers to the distance between the side of the projection screen 30 connected to the crossbar assembly 41 and the housing 10 . The fourth distance threshold is greater than the third distance threshold and is a fixed value pre-stored in the control assembly 50 .

[0142] In the embodiment of the present disclosure, the control component 50 can obtain the descending distance of the projection screen 30 in real time during the process of controlling the projection screen 30 to retract into the receiving slot 00. When detecting whether the descending distance is greater than a fourth distance threshold, it can be determined that the distance between the projection screen 30 and the housing 10 is relatively close. For example, the distance can be 30 millimeters (mm). In this case, the control component 50 can turn off the signal detector 20 and increase the frequency of the descending drive signal provided to the screen drive component 40 to quickly retract the projection screen 30 into the receiving slot 00.

[0143] Optionally, the control component 50 is further configured to, during each detection cycle while controlling the projection screen 30 to retract into the receiving slot 00, obtain the distance traveled by the projection screen 30 within the detection cycle. The control component 50 then detects whether the travel distance is greater than a first distance threshold. If the travel distance is greater than the first distance threshold, indicating that the projection screen 20 is moving rapidly, the frequency of the descending drive signal provided to the screen drive component 40 may be reduced, thereby reducing the speed of the projection screen 30. If the travel distance is less than or equal to the first distance threshold, the control component 50 detects whether the travel distance is less than a second distance threshold. If the travel distance is less than the second distance threshold, indicating that the projection screen 30 is moving slowly, the frequency of the descending drive signal provided to the screen drive component 40 may be increased, thereby increasing the speed of the projection screen 30.

[0144] The first distance threshold is greater than the second distance threshold, and the moving speed of the projection screen 30 is positively correlated with the frequency. That is, the greater the frequency of the descending drive signal, the faster the moving speed of the projection screen 30; and the smaller the frequency of the descending drive signal, the slower the moving speed of the projection screen 30.

[0145] In the embodiment of the present disclosure, when controlling the projection screen 30 to be retracted from the receiving slot 00, the moving speed of the projection screen 30 can be dynamically adjusted according to the moving distance of the projection screen 30 during the detection cycle, thereby improving the flexibility of the projection screen lifting control.

[0146] refer to Figure 9 In the process of controlling the projection screen 30 to be retracted from the receiving slot 00, the control component 50 can determine the moving distance d of the projection screen 30 within the detection period based on the emission time t3 of the optical signal emitted by the distance detector 80 and the reception time t4 of the optical signal reflected by the crossbar component 41.

[0147] Optional, reference Figure 5If distance detectors 80 are provided on both sides of the long side of the opening of the receiving slot 00, the control component 50 can determine two movement distances based on the two distance detectors 80 when controlling the projection screen 30 to be retracted from the receiving slot 00. The control component 50 can use the average of the two movement distances as the movement distance of the projection screen 30 during the detection cycle.

[0148] Optionally, the control component 50 may also determine the descending distance of the projection screen 30 according to the distance detector 80 , wherein the emission time of the light signal is the time when the control component 50 provides the descending driving signal to the screen driving component 40 .

[0149] Meanwhile, if distance detectors 80 are provided on both sides of the long side of the opening of the receiving slot 00, the control component 50 can determine two lowering distances based on the two distance detectors 80. The control component 50 can use the average of the two lowering distances as the lowering distance of the projection screen 30.

[0150] refer to Figure 5 and Figure 8 Distance detectors 80 are provided on both sides of the long side of the opening of the receiving slot 00. During the process of controlling the lowering of the projection screen 30 by the two motors 43, the control component 50 determines two moving distances based on the two distance detectors during each detection cycle. It then detects whether the difference between the two moving distances is greater than a difference threshold. If the difference is greater than the difference threshold, it indicates that the difference in moving distance between the two sides of the projection screen 30 is significant. Therefore, the frequency of the lowering drive signal provided to either screen drive circuit 42 can be adjusted to ensure that the difference in moving distance between the two sides of the projection screen 30 remains within a constant range. If the difference is less than or equal to the difference threshold, it indicates that the difference in moving distance between the two sides of the projection screen 30 is small, and there is no need to adjust the frequency of the lowering drive signal provided to the two screen drive circuits 42.

[0151] Optionally, when adjusting the frequency of the descending drive signal provided to any one of the screen drive circuits 42, the control component 50 may reduce the frequency of the descending drive signal provided to one screen drive circuit 42, thereby reducing the movement speed of one side of the projection screen 30. Alternatively, the control component 50 may increase the frequency of the descending drive signal provided to the other screen drive circuit 42, thereby increasing the movement speed of the other side of the projection screen 30.

[0152] refer to Figure 9The multimedia component 70 may further include a power amplifier component 72 and a speaker 73. The power amplifier component 72 is connected to the audio and video control circuit 71 and the speaker 74, respectively. After receiving the first detection signal sent by the signal detector 20, the control component 50 may also send an alarm message to the audio and video control circuit 71. After receiving the alarm message, the audio and video control circuit 71 may send the alarm message to the power amplifier component 72. The power amplifier component 72 drives the speaker 74 to emit an alarm sound, thereby prompting the user to remove the foreign object in time.

[0153] refer to Figure 5 and Figure 9 The projection device may further include an eye protection component 90 and a display control component 100. The eye protection component 90 is disposed on the front side of the housing 10. The eye protection component 90 may include a human eye protection sensor 91, an amplification circuit 92, a comparison circuit 93, and a trigger 94. The display control component 100 may include a display driver circuit 1001 and a slave control circuit 1002. The slave control circuit 1002 may be a microcontroller unit (MCU).

[0154] The amplifier circuit 92 is connected to the eye protection sensor 91 and the comparison circuit 93, respectively. The trigger 94 is connected to the comparison circuit 93 and the slave control circuit 1002, respectively. The slave control circuit 1002 is connected to the audio and video control circuit 71. The eye protection sensor 90 can be an infrared sensor or a non-infrared sensor.

[0155] Before controlling the projection screen 30 to rise, or during its descent, the eye protection sensor 91 detects the distance between the human body and the projection device and transmits the detected distance to the amplifier circuit 92 and the comparison circuit 93. The comparison circuit 93 compares the distance with a pre-stored distance threshold. If the distance threshold is less than the threshold, a control signal is provided to the trigger 94. When the slave control circuit 1002 detects that the number of pulse signals output by the trigger 94 per unit time is greater than the threshold, it determines that the human body is close to the projection device, indicating a possibility that the person is blocking the rise or fall of the projection screen. The slave control circuit 1002 then transmits an alarm message to the audio and video control circuit 71. The audio and video control circuit 71 transmits the received alarm message to the power amplifier component 72, which drives the speaker 74 to emit an alarm sound to remind the user to stay away from the projection screen 30.

[0156] refer to Figure 9The projection device may further include a light source driving assembly 110 and a laser light source 120. The laser light source 120 is configured to emit laser light. The laser light source 120 includes a red laser, a green laser assembly, a blue laser assembly, and a yellow laser assembly. A glass lens with a light-combining function is provided on the light-emitting side of each laser.

[0157] The multimedia component 70 may further include a first memory 73. The first memory 73 is connected to the audio and video control circuit 71. The first memory 73 may be used to store images to be projected and displayed. The audio and video control circuit 71 is further used to obtain the images to be projected and displayed from the first memory 73, and send the images to be projected and displayed to the slave control circuit 1002, and then to the display driver circuit 1001. The display driver circuit 1001 may output a red PWM signal R_PWM corresponding to the red laser assembly based on the red primary color component of the image to be displayed, a green PWM signal G_PWM corresponding to the green laser assembly based on the green primary color component of the image to be displayed, a blue PWM signal B_PWM corresponding to the blue laser assembly based on the blue primary color component of the image to be displayed, and a yellow PWM signal Y_PWM corresponding to the yellow laser assembly based on the yellow primary color component of the image to be displayed. Furthermore, the display driving circuit 1001 may output an enable signal R_EN corresponding to the red laser assembly based on the duration of the red laser assembly being on during the driving cycle, an enable signal G_EN corresponding to the green laser assembly based on the duration of the green laser assembly being on during the driving cycle, an enable signal B_EN corresponding to the blue laser assembly based on the duration of the blue laser assembly being on during the driving cycle, and an enable signal Y_EN corresponding to the yellow laser assembly based on the duration of the yellow laser assembly being on during the driving cycle.

[0158] refer to Figure 9 The display control component 100 may further include a second memory 1003 for storing primary color scale values ​​of pixels in the image to be projected. The display driver circuit 1001 is further configured to retrieve the stored primary color scale values ​​of the pixels in the image to be projected from the second memory and control the light valve to flip according to the primary color scale values ​​of the pixels in the image to be projected, thereby projecting the image to be projected onto the projection screen.

[0159] In the embodiment of the present disclosure, the slave control circuit 1001 is also used to control the ambient temperature inside the housing 10 and the temperature of the laser light source 120 , and adjusts the ambient temperature inside the housing 10 and the temperature of the laser light source 120 by controlling the fan.

[0160] In summary, the embodiments of the present disclosure provide a projection device, wherein a signal detector in the projection device detects whether a foreign object is present at the opening of the receiving slot in response to a shutdown command. When a foreign object is detected at the opening of the receiving slot, a fifth detection signal is sent to the control component. After receiving the fifth detection signal, the control component can stop providing a descending drive signal to the screen drive component. This avoids the situation where the projection screen is blocked by the foreign object when the foreign object is present at the opening of the receiving slot, thereby improving the reliability of the projection screen descent control. At the same time, it can avoid the situation where the user's hand is placed at the opening of the receiving slot during the projection screen descent and is pinched, thereby ensuring the safety of the user.

[0161] In the embodiments of the present disclosure, reference Figure 2 The signal detector 20 is further configured to detect whether there is a foreign object at the opening of the receiving slot 00 in response to a power-off command or when the projection screen 30 descends a distance greater than a third distance threshold, and to send a fifth detection signal to the control component 50 when a foreign object is detected at the opening of the receiving slot 00. When no foreign object is detected at the opening of the receiving slot 00, a sixth detection signal is sent to the control component 50.

[0162] refer to Figure 2 The control component 50 is further configured to stop providing the descending drive signal to the screen driving component 40 when the fifth detection signal is received. The control component 50 is configured to provide the descending drive signal to the screen driving component 40 when the sixth detection signal is received.

[0163] refer to Figure 2 The screen driving assembly 40 is connected to the projection screen 30 and is used to control the projection screen 30 to retract into the receiving slot 00 under the control of the descending driving signal.

[0164] refer to Figure 2 The control component 50 is further configured to increase the frequency of the descending driving signal provided to the screen driving component 30 when the descending distance of the projection screen 00 is greater than a fourth distance threshold during the process of controlling the projection screen 30 to retract into the receiving slot 00 .

[0165] The fourth distance threshold is greater than the third distance threshold, and the moving speed of the projection screen is positively correlated with the frequency.

[0166] In summary, the embodiments of the present disclosure provide a projection device in which a signal detector detects whether a foreign object is present at the opening of the receiving slot in response to a shutdown command. When a foreign object is detected at the opening of the receiving slot, a fifth detection signal is sent to the control component. Upon receiving the fifth detection signal, the control component can stop providing a descending drive signal to the screen drive component. This prevents the projection screen from being blocked by the foreign object when descending when the foreign object is present at the opening of the receiving slot, thereby improving the reliability of the projection screen descent control. Furthermore, this prevents the projection screen from being pinched by a user's hand placed at the opening of the receiving slot during descent, thereby ensuring user safety. Furthermore, since the projection screen's movement speed is increased when the descent distance of the projection screen exceeds the fourth distance threshold, the retraction of the projection screen into the receiving slot can be accelerated.

[0167] Figure 16 This is a flow chart of a method for controlling the lifting of a projection screen provided by an embodiment of the present disclosure. The lifting control method can be applied to Figures 1 to 13 As shown in any one of the control components 50 located in the housing 10 of the projection device, the projection device may further include a signal detector 20, a projection screen 30, and a screen drive component 40. A receiving slot 00 for receiving the projection screen 30 is provided on one side of the housing 10. The control component 50 is connected to the signal detector 20 and the screen drive component 40 respectively. Figure 16 As shown, the method may include:

[0168] Step 1601: When a first detection signal sent by a signal detector is received, the rising drive signal is stopped from being provided to the screen drive assembly.

[0169] Step 1602: When a second detection signal sent by the signal detector is received, a rising drive signal is provided to the screen drive assembly.

[0170] The rising drive signal is used to control the screen drive assembly 40 to control the projection screen 30 to rise from the receiving slot 00. The first detection signal is sent by the signal detector 20 to the control assembly 50 in response to a power-on command, detecting whether a foreign object is present at the opening of the receiving slot 00. The second detection signal is sent by the signal detector 20 to the control assembly 50 in response to a power-on command, detecting whether a foreign object is present at the opening of the receiving slot 00, and detecting that no foreign object is present at the opening of the receiving slot 00.

[0171] In summary, the disclosed embodiments provide a method for controlling the raising and lowering of a projection screen. In this method, a signal detector can detect the presence of a foreign object at the opening of a receiving slot in response to a power-on command. Upon detecting the presence of a foreign object at the opening of the receiving slot, the signal detector sends a first detection signal to a control component. Upon receiving the first detection signal, the control component can stop providing a drive signal to the screen drive component. This prevents the projection screen from being blocked from rising by a foreign object at the opening of the receiving slot, thereby improving the reliability of the projection screen's raising control.

[0172] Figure 17 FIG. 1 is a flow chart of another method for controlling the lifting of a projection screen provided by an embodiment of the present disclosure. Figure 17 As shown, the method may include:

[0173] Step 1701: When a fifth detection signal is received from a signal detector, the supply of the descending drive signal to the screen driving assembly is stopped.

[0174] Step 1702: When the sixth detection signal sent by the signal detector is received, a descending driving signal is provided to the screen driving assembly.

[0175] The descending drive signal is used to control the screen drive assembly 40 to control the projection screen 30 to retract into the receiving slot 00. The fifth detection signal is sent by the signal detector 20 to the control assembly 50 in response to a shutdown command or when the projection screen 30 has descended a distance greater than a third distance threshold, detecting whether a foreign object is present at the opening of the receiving slot 00. The sixth detection signal is sent by the signal detector to the control assembly 50 in response to a shutdown command or when the projection screen 30 has descended a distance greater than a third distance threshold, detecting whether a foreign object is present at the opening of the receiving slot 00. The sixth detection signal is sent by the signal detector to the control assembly 50 in response to a shutdown command or when the projection screen 30 has descended a distance greater than a third distance threshold, detecting whether a foreign object is present at the opening of the receiving slot 00.

[0176] In summary, the embodiments of the present disclosure provide a method for controlling the lifting of a projection screen. The method can detect whether a foreign object is present at the opening of the receiving slot in response to a power-off command or when the projection screen has descended a distance greater than a third distance threshold. When a foreign object is detected at the opening of the receiving slot, a fifth detection signal is sent to the control component. Upon receiving the fifth detection signal, the control component can stop providing a descending drive signal to the screen drive component. This prevents the projection screen from being blocked by the foreign object when the projection screen is lowered, thereby improving the reliability of the projection screen descent control. At the same time, this method can prevent the projection screen from being pinched by a user's hand at the opening of the receiving slot during its descent, thereby ensuring user safety.

[0177] Figure 18 FIG. 1 is a flow chart of another method for controlling the lifting of a projection screen provided by an embodiment of the present disclosure. Figure 18 As shown, the method may include:

[0178] Step 1801: When a fifth detection signal is received from a signal detector, the supply of the descending drive signal to the screen drive assembly is stopped.

[0179] Step 1802: When the sixth detection signal sent by the signal detector is received, a descending driving signal is provided to the screen driving assembly.

[0180] Step 1803: When the descending distance of the projection screen is greater than a fourth distance threshold, increase the frequency of the descending driving signal provided to the screen driving assembly.

[0181] The descending drive signal is used to control the screen drive assembly 40 to retract the projection screen 30 into the receiving slot 00. The fifth detection signal is sent to the control assembly 50 by the signal detector 20 in response to a shutdown command or when the descending distance of the projection screen 30 exceeds a third distance threshold, detecting whether a foreign object is present at the opening of the receiving slot 00. The sixth detection signal is sent to the control assembly 50 by the signal detector 20 in response to a shutdown command or when the descending distance of the projection screen 30 exceeds a third distance threshold, detecting whether a foreign object is present at the opening of the receiving slot 00. The fourth distance threshold is greater than the third distance threshold, and the moving speed of the projection screen 30 is positively correlated with the frequency.

[0182] In summary, embodiments of the present disclosure provide a method for controlling the raising and lowering of a projection screen. In response to a power-off command or when the projection screen has descended a distance greater than a third distance threshold, the method detects the presence of a foreign object at the opening of the receiving slot. Upon detecting the presence of a foreign object at the opening of the receiving slot, the method sends a fifth detection signal to a control component. Upon receiving the fifth detection signal, the control component can stop providing the descending drive signal to the screen drive component. This prevents the projection screen from being blocked by the foreign object during descent when it is located at the opening of the receiving slot, thereby improving the reliability of the projection screen descent control. Furthermore, this method prevents a user's hand from being pinched by the opening of the receiving slot during descent, thereby ensuring user safety. Furthermore, by increasing the projection screen's movement speed when the projection screen has descended a distance greater than a fourth distance threshold, the projection screen can be retracted into the receiving slot more quickly.

[0183] The above description is merely an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.

Claims

1. A projection device, characterized in that: The projection device includes: a housing, a signal detector, a projection screen, a screen drive assembly, and a control assembly located in the housing; A receiving groove for receiving the projection screen is provided on one side of the housing; The signal detector is connected to the control component and is used to detect whether there is a foreign object at the opening of the receiving slot in response to a power-on instruction, and when it is detected that there is a foreign object at the opening of the receiving slot, send a first detection signal to the control component, and when it is detected that there is no foreign object at the opening of the receiving slot, send a second detection signal to the control component; The control component is further connected to the screen drive component, and is configured to stop providing the rising drive signal to the screen drive component when receiving the first detection signal, and provide the rising drive signal to the screen drive component when receiving the second detection signal; The screen driving assembly is connected to the projection screen and is used to control the projection screen to rise out of the accommodating slot under the control of the rising driving signal; The screen drive assembly includes a crossbar assembly, a guide rail disposed within the receiving slot, and two drive subassemblies disposed on opposite sides of the receiving slot. The crossbar assembly is connected to the projection screen. Each drive subassembly includes a screen drive circuit, a motor, a lift rod, and a lift rod drive assembly. Each lift rod drive assembly includes a slider drive subassembly, a slider, and a power rod. Each lift rod includes a first rod body, a second rod body, and an elastic component for connecting the two rod bodies. In each drive subassembly, the motor is connected to a corresponding screen drive circuit. One end of the first rod body is connected to one end of the crossbar assembly, and the other end is connected to one end of the second rod body via an elastic component. The other end of the second rod body is connected to the guide rail. One end of the power rod is connected to the slider, and the other end of the power rod is connected to a side wall of the second rod body near the guide rail. Each motor, driven by a first drive current provided by the corresponding screen drive circuit, drives each slider drive subassembly to push the corresponding slider to slide along the guide rail toward the side near the motor, thereby pushing the power rod toward the side near the motor. The power rod then pushes the first rod body upward through the second rod body, thereby pushing the lift rod upward. The control component is further configured to: during the process of controlling the projection screen to rise from the receiving slot, obtain, at each detection period, a movement distance of the projection screen within the detection period; if the movement distance is greater than a first distance threshold, reduce the frequency of the rising drive signal provided to the screen drive component; and if the movement distance is less than a second distance threshold, increase the frequency of the rising drive signal provided to the screen drive component; wherein, if the first distance threshold is greater than the second distance threshold, the movement speed of the projection screen is positively correlated with the frequency; Distance detectors are provided on both sides of the long side of the opening of the receiving slot, and the control component is used to determine two moving distances based on the two distance detectors, and use the average of the two moving distances as the moving distance of the projection screen during the detection period; Furthermore, during the process of controlling the projection screen to ascend using the two motors, the control component determines two moving distances using the two distance detectors at each detection cycle, and then detects whether the difference between the two moving distances is greater than a difference threshold. If the difference is greater than the difference threshold, the frequency of the ascending drive signal provided to either screen drive circuit is adjusted, thereby ensuring that the difference in the moving distances on both sides of the projection screen remains within a constant range. If the difference is less than or equal to the difference threshold, there is no need to adjust the frequency of the ascending drive signal provided to the two screen drive circuits.

2. The projection device according to claim 1, wherein: The signal detector includes a signal transmitter and a signal receiver; the signal transmitter and the signal receiver are arranged on two sides of the receiving groove opposite to each other; Alternatively, the signal transmitter and the signal receiver are both arranged on one side of the receiving slot; Alternatively, the signal transmitter and the signal receiver are both arranged in the receiving slot; Alternatively, the signal transmitter and the signal receiver are both arranged on the crossbar assembly; Alternatively, one of the signal transmitter and the signal receiver is disposed in the receiving groove, and the other is disposed on the crossbar assembly.

3. The projection device according to any one of claims 1 to 2, characterized in that: The control component is also used to: When the second detection signal is received, the signal detector is turned off.

4. A projection device, characterized in that: The projection device includes: a housing, a signal detector, a projection screen, a screen drive assembly, and a control assembly located in the housing; A receiving groove for receiving the projection screen is provided on one side of the housing; The signal detector is connected to the control component and is configured to detect whether there is a foreign object at the opening of the receiving slot in response to a shutdown instruction or when the projection screen has descended a distance greater than a third distance threshold, and to send a fifth detection signal to the control component when a foreign object is detected at the opening of the receiving slot, and to send a sixth detection signal to the control component when no foreign object is detected at the opening of the receiving slot; The control component is further connected to the screen driving component, and is configured to stop providing the descending driving signal to the screen driving component when receiving the fifth detection signal, and provide the descending driving signal to the screen driving component when receiving the sixth detection signal; The screen driving assembly is connected to the projection screen and is used to control the projection screen to retract into the receiving slot under the control of the descending driving signal; The screen drive assembly includes a crossbar assembly, a guide rail arranged in the receiving slot, and two drive subassemblies arranged on both sides of the receiving slot. The crossbar assembly is connected to the projection screen. Each drive subassembly includes a screen drive circuit, a motor, a lifting rod, and a lifting rod drive assembly. Each lifting rod drive assembly includes a slider drive subassembly, a slider, and a power rod. Each lifting rod includes a first rod body, a second rod body, and an elastic assembly for connecting the two rod bodies. In each drive subassembly, the motor is connected to a corresponding screen drive circuit. The first rod body is connected to the second rod body. One end is connected to one end of the crossbar assembly, and the other end is connected to one end of the second rod body through an elastic component. The other end of the second rod body is connected to the guide rail. One end of the power rod is connected to the slider, and the other end of the power rod is connected to the side wall of the second rod body near the guide rail. Each motor, driven by the second driving current provided by the corresponding screen driving circuit, drives each slider driving subassembly to pull the corresponding slider to slide along the guide rail toward the side away from the motor, thereby pulling the power rod to move toward the side close to the motor. The power rod then pulls the first rod body down through the second rod body, thereby pulling the lifting rod down. In the process of controlling the retraction of the projection screen into the accommodating slot, the movement distance of the projection screen within each detection period is obtained; if the movement distance is greater than a first distance threshold, the frequency of the descending drive signal provided to the screen drive assembly is reduced; if the movement distance is less than a second distance threshold, the frequency of the descending drive signal provided to the screen drive assembly is increased; wherein the first distance threshold is greater than the second distance threshold, the movement speed of the projection screen is positively correlated with the frequency, and distance detectors are provided on both sides of the long side of the opening of the accommodating slot. The control component is configured to determine two movement distances based on the two distance detectors, and use the average of the two movement distances as the movement distance of the projection screen within the detection period; Furthermore, during the process of controlling the projection screen to descend by the two motors, the control component determines two moving distances according to the two distance detectors at each detection cycle, and then detects whether the difference between the two moving distances is greater than a difference threshold. If the difference is greater than the difference threshold, the frequency of the descending drive signal provided to either screen drive circuit is adjusted, thereby ensuring that the difference in the moving distances on both sides of the projection screen is within a constant range. If the difference is less than or equal to the difference threshold, there is no need to adjust the frequency of the descending drive signal provided to the two screen drive circuits.

5. The projection device according to claim 4, characterized in that: The signal detector includes a signal transmitter and a signal receiver; The signal transmitter and the signal receiver are arranged oppositely on two sides of the receiving slot; Alternatively, the signal transmitter and the signal receiver are both arranged on one side of the receiving slot; Alternatively, the signal transmitter and the signal receiver are both arranged in the receiving slot; Alternatively, the signal transmitter and the signal receiver are both arranged on the crossbar assembly; Alternatively, one of the signal transmitter and the signal receiver is disposed in the receiving groove, and the other is disposed on the crossbar assembly.

6. The projection device according to any one of claims 4 to 5, characterized in that: The control component is further used to: When the descending distance of the projection screen is greater than a fourth distance threshold, turning off the signal detector and increasing the frequency of the descending drive signal provided to the screen drive assembly; The fourth distance threshold is greater than the third distance threshold.

7. A projection device, characterized in that: The projection device includes: a housing, a signal detector, a projection screen, a screen drive assembly, and a control assembly located in the housing; A receiving groove for receiving the projection screen is provided on one side of the housing; The signal detector is connected to the control component and is configured to detect whether there is a foreign object at the opening of the receiving slot in response to a shutdown instruction or when the projection screen has descended a distance greater than a third distance threshold, and to send a fifth detection signal to the control component when a foreign object is detected at the opening of the receiving slot, and to send a sixth detection signal to the control component when no foreign object is detected at the opening of the receiving slot; The control component is further connected to the screen driving component, and is configured to stop providing the descending driving signal to the screen driving component when receiving the fifth detection signal, and provide the descending driving signal to the screen driving component when receiving the sixth detection signal; The screen driving assembly is connected to the projection screen and is used to control the projection screen to retract into the receiving slot under the control of the descending driving signal; The control component is further configured to increase the frequency of the descending drive signal provided to the screen drive component when the descending distance of the projection screen is greater than a fourth distance threshold; Wherein, the fourth distance threshold is greater than the third distance threshold, and the moving speed of the projection screen is positively correlated with the frequency; The screen drive assembly includes a crossbar assembly, a guide rail arranged in the receiving slot, and two drive subassemblies arranged on both sides of the receiving slot. The crossbar assembly is connected to the projection screen. Each drive subassembly includes a screen drive circuit, a motor, a lifting rod, and a lifting rod drive assembly. Each lifting rod drive assembly includes a slider drive subassembly, a slider, and a power rod. Each lifting rod includes a first rod body, a second rod body, and an elastic assembly for connecting the two rod bodies. In each drive subassembly, the motor is connected to a corresponding screen drive circuit. The first rod body is connected to the second rod body. One end is connected to one end of the crossbar assembly, and the other end is connected to one end of the second rod body through an elastic component. The other end of the second rod body is connected to the guide rail. One end of the power rod is connected to the slider, and the other end of the power rod is connected to the side wall of the second rod body near the guide rail. Each motor, driven by the second driving current provided by the corresponding screen driving circuit, drives each slider driving subassembly to pull the corresponding slider to slide along the guide rail toward the side away from the motor, thereby pulling the power rod to move toward the side close to the motor. The power rod then pulls the first rod body down through the second rod body, thereby pulling the lifting rod down. In the process of controlling the retraction of the projection screen into the accommodating slot, the movement distance of the projection screen within each detection period is obtained; if the movement distance is greater than a first distance threshold, the frequency of the descending drive signal provided to the screen drive assembly is reduced; if the movement distance is less than a second distance threshold, the frequency of the descending drive signal provided to the screen drive assembly is increased; wherein the first distance threshold is greater than the second distance threshold, the movement speed of the projection screen is positively correlated with the frequency, and distance detectors are provided on both sides of the long side of the opening of the accommodating slot. The control component is configured to determine two movement distances based on the two distance detectors, and use the average of the two movement distances as the movement distance of the projection screen within the detection period; Furthermore, during the process of controlling the projection screen to descend by the two motors, the control component determines two moving distances according to the two distance detectors at each detection cycle, and then detects whether the difference between the two moving distances is greater than a difference threshold. If the difference is greater than the difference threshold, the frequency of the descending drive signal provided to either screen drive circuit is adjusted, thereby ensuring that the difference in the moving distances on both sides of the projection screen is within a constant range. If the difference is less than or equal to the difference threshold, there is no need to adjust the frequency of the descending drive signal provided to the two screen drive circuits.

8. A method for controlling the lifting of a projection screen, characterized in that: A control assembly is applied to a housing of a projection device, the projection device further comprising: a signal detector, a projection screen, and a screen drive assembly, wherein a side of the housing is provided with a receiving slot for receiving the projection screen; the control assembly is respectively connected to the signal detector and the screen drive assembly, and the screen drive assembly is connected to the projection screen; the method comprises: When receiving the first detection signal sent by the signal detector, stopping providing the rising drive signal to the screen driving component; When receiving the second detection signal sent by the signal detector, providing an ascending drive signal to the screen drive assembly, wherein the ascending drive signal is used to control the screen drive assembly to control the projection screen to ascend from the receiving slot; Wherein, the first detection signal is sent to the control component by the signal detector in response to the power-on instruction to detect whether there is a foreign object at the opening of the receiving slot, and when the foreign object is detected at the opening of the receiving slot, the second detection signal is sent to the control component by the signal detector in response to the power-on instruction to detect whether there is a foreign object at the opening of the receiving slot, and when the foreign object is detected at the opening of the receiving slot, the screen drive assembly includes a crossbar assembly, a guide rail arranged in the receiving slot, and two drive subassemblies arranged on both sides of the receiving slot, the crossbar assembly is connected to the projection screen, each drive subassembly includes a screen drive circuit, a motor, a lifting rod, and a lifting rod drive assembly, and each lifting rod drive assembly includes a slider drive subassembly The lifting rod comprises a first rod body, a second rod body and an elastic component for connecting the two rod bodies; in each driving subassembly, a motor is connected to a corresponding screen driving circuit, one end of the first rod body is connected to one end of the crossbar assembly, and the other end is connected to one end of the second rod body through an elastic component, the other end of the second rod body is connected to the guide rail, one end of the power rod is connected to the slider, and the other end of the power rod is connected to the side wall of the second rod body near the guide rail; each motor, driven by a first driving current provided by the corresponding screen driving circuit, drives each slider driving subassembly to push the corresponding slider to slide along the guide rail toward the side near the motor, so as to push the power rod to move toward the side near the motor, and the power rod then pushes the first rod body to rise through the second rod body, thereby pushing the lifting rod to rise; In the process of controlling the projection screen to rise from the accommodating slot, the distance moved by the projection screen within each detection period is obtained; if the movement distance is greater than a first distance threshold, the frequency of the rising drive signal provided to the screen drive assembly is reduced; if the movement distance is less than a second distance threshold, the frequency of the rising drive signal provided to the screen drive assembly is increased; wherein the first distance threshold is greater than the second distance threshold, and the movement speed of the projection screen is positively correlated with the frequency; distance detectors are provided on both sides of the long side of the opening of the accommodating slot, and the control component is configured to determine two movement distances based on the two distance detectors, and use the average of the two movement distances as the movement distance of the projection screen within the detection period; Furthermore, during the process of controlling the projection screen to ascend using the two motors, the control component determines two moving distances using the two distance detectors at each detection cycle, and then detects whether the difference between the two moving distances is greater than a difference threshold. If the difference is greater than the difference threshold, the frequency of the ascending drive signal provided to either screen drive circuit is adjusted, thereby ensuring that the difference in the moving distances on both sides of the projection screen remains within a constant range. If the difference is less than or equal to the difference threshold, there is no need to adjust the frequency of the ascending drive signal provided to the two screen drive circuits.

9. A method for controlling the lifting of a projection screen, characterized in that: A control assembly is applied to a housing of a projection device, the projection device further comprising: a signal detector, a projection screen, and a screen drive assembly, wherein a side of the housing is provided with a receiving slot for receiving the projection screen; the control assembly is respectively connected to the signal detector and the screen drive assembly, and the screen drive assembly is connected to the projection screen; the method comprises: When receiving the fifth detection signal sent by the signal detector, stopping providing the descending drive signal to the screen driving assembly; When receiving the sixth detection signal sent by the signal detector, a descending drive signal is provided to the screen drive assembly, wherein the descending drive signal is used to control the screen drive assembly to control the projection screen to retract into the receiving slot; The fifth detection signal is generated when the signal detector detects whether a foreign object is present at the opening of the receiving slot in response to a power-off instruction or when the projection screen has descended a distance greater than a third distance threshold, and is sent to the control component when the foreign object is detected at the opening of the receiving slot. The sixth detection signal is generated when the signal detector detects whether a foreign object is present at the opening of the receiving slot in response to a power-off instruction or when the projection screen has descended a distance greater than a third distance threshold, and is sent to the control component when the foreign object is detected at the opening of the receiving slot. The screen drive assembly includes a crossbar assembly, a guide rail arranged in the receiving slot, and two drive subassemblies arranged on both sides of the receiving slot. The crossbar assembly is connected to the projection screen. Each drive subassembly includes a screen drive circuit, a motor, a lifting rod, and a lifting rod drive assembly. Each lifting rod drive assembly includes a slider drive subassembly, a slider, and a power rod. Each lifting rod includes a first rod body, a second rod body, and an elastic assembly for connecting the two rod bodies. In each drive subassembly, the motor is connected to a corresponding screen drive circuit. The first rod body is connected to the second rod body. One end is connected to one end of the crossbar assembly, and the other end is connected to one end of the second rod body through an elastic component. The other end of the second rod body is connected to the guide rail. One end of the power rod is connected to the slider, and the other end of the power rod is connected to the side wall of the second rod body near the guide rail. Each motor, driven by the second driving current provided by the corresponding screen driving circuit, drives each slider driving subassembly to pull the corresponding slider to slide along the guide rail toward the side away from the motor, thereby pulling the power rod to move toward the side close to the motor. The power rod then pulls the first rod body down through the second rod body, thereby pulling the lifting rod down. In the process of controlling the retraction of the projection screen into the accommodating slot, the movement distance of the projection screen within each detection period is obtained; if the movement distance is greater than a first distance threshold, the frequency of the descending drive signal provided to the screen drive assembly is reduced; if the movement distance is less than a second distance threshold, the frequency of the descending drive signal provided to the screen drive assembly is increased; wherein the first distance threshold is greater than the second distance threshold, the movement speed of the projection screen is positively correlated with the frequency, and distance detectors are provided on both sides of the long side of the opening of the accommodating slot. The control component is configured to determine two movement distances based on the two distance detectors, and use the average of the two movement distances as the movement distance of the projection screen within the detection period; Furthermore, during the process of controlling the projection screen to descend by the two motors, the control component determines two moving distances according to the two distance detectors at each detection cycle, and then detects whether the difference between the two moving distances is greater than a difference threshold. If the difference is greater than the difference threshold, the frequency of the descending drive signal provided to either screen drive circuit is adjusted, thereby ensuring that the difference in the moving distances on both sides of the projection screen is within a constant range. If the difference is less than or equal to the difference threshold, there is no need to adjust the frequency of the descending drive signal provided to the two screen drive circuits.

10. A method for controlling the lifting of a projection screen, characterized in that: A control assembly is applied to a housing of a projection device, the projection device further comprising: a signal detector, a projection screen, and a screen drive assembly, wherein a side of the housing is provided with a receiving slot for receiving the projection screen; the control assembly is respectively connected to the signal detector and the screen drive assembly, and the screen drive assembly is connected to the projection screen; the method comprises: When receiving the fifth detection signal sent by the signal detector, stopping providing the descending drive signal to the screen driving assembly; When receiving the sixth detection signal sent by the signal detector, a descending drive signal is provided to the screen drive assembly, wherein the descending drive signal is used to control the screen drive assembly to control the projection screen to be retracted into the receiving slot; When the descending distance of the projection screen is greater than a fourth distance threshold, increasing the frequency of the descending drive signal provided to the screen drive assembly; The fifth detection signal is sent to the control component by the signal detector when the signal detector detects whether a foreign object is present at the opening of the accommodating slot in response to a power-off instruction or when the projection screen has descended a distance greater than a third distance threshold, and when the foreign object is detected at the opening of the accommodating slot. The sixth detection signal is sent to the control component when the signal detector detects whether a foreign object is present at the opening of the accommodating slot in response to a power-off instruction or when the projection screen has descended a distance greater than a third distance threshold, and when the foreign object is detected at the opening of the accommodating slot. The fourth distance threshold is greater than the third distance threshold, and the moving speed of the projection screen is positively correlated with the frequency. The screen drive assembly includes a crossbar assembly, a guide rail arranged in the receiving slot, and two drive subassemblies arranged on both sides of the receiving slot. The crossbar assembly is connected to the projection screen. Each drive subassembly includes a screen drive circuit, a motor, a lifting rod, and a lifting rod drive assembly. Each lifting rod drive assembly includes a slider drive subassembly, a slider, and a power rod. Each lifting rod includes a first rod body, a second rod body, and an elastic assembly for connecting the two rod bodies. In each drive subassembly, the motor is connected to a corresponding screen drive circuit. The first rod body is connected to the second rod body. One end is connected to one end of the crossbar assembly, and the other end is connected to one end of the second rod body through an elastic component. The other end of the second rod body is connected to the guide rail. One end of the power rod is connected to the slider, and the other end of the power rod is connected to the side wall of the second rod body near the guide rail. Each motor, driven by the second driving current provided by the corresponding screen driving circuit, drives each slider driving subassembly to pull the corresponding slider to slide along the guide rail toward the side away from the motor, thereby pulling the power rod to move toward the side close to the motor. The power rod then pulls the first rod body down through the second rod body, thereby pulling the lifting rod down. In the process of controlling the retraction of the projection screen into the accommodating slot, the movement distance of the projection screen within each detection period is obtained; if the movement distance is greater than a first distance threshold, the frequency of the descending drive signal provided to the screen drive assembly is reduced; if the movement distance is less than a second distance threshold, the frequency of the descending drive signal provided to the screen drive assembly is increased; wherein the first distance threshold is greater than the second distance threshold, the movement speed of the projection screen is positively correlated with the frequency, and distance detectors are provided on both sides of the long side of the opening of the accommodating slot. The control component is configured to determine two movement distances based on the two distance detectors, and use the average of the two movement distances as the movement distance of the projection screen within the detection period; Furthermore, during the process of controlling the projection screen to descend by the two motors, the control component determines two moving distances according to the two distance detectors at each detection cycle, and then detects whether the difference between the two moving distances is greater than a difference threshold. If the difference is greater than the difference threshold, the frequency of the descending drive signal provided to either screen drive circuit is adjusted, thereby ensuring that the difference in the moving distances on both sides of the projection screen is within a constant range. If the difference is less than or equal to the difference threshold, there is no need to adjust the frequency of the descending drive signal provided to the two screen drive circuits.

Images