CN113376949A - Laser projection system and method for controlling ascending and descending of projection screen - Google Patents

Laser projection system and method for controlling ascending and descending of projection screen Download PDF

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Publication number
CN113376949A
CN113376949A CN202010115286.3A CN202010115286A CN113376949A CN 113376949 A CN113376949 A CN 113376949A CN 202010115286 A CN202010115286 A CN 202010115286A CN 113376949 A CN113376949 A CN 113376949A
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China
Prior art keywords
projection screen
projection
projected
content area
effective content
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Granted
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CN202010115286.3A
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Chinese (zh)
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CN113376949B (en
Inventor
肖纪臣
陈许
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Qingdao Hisense Laser Display Co Ltd
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Qingdao Hisense Laser Display Co Ltd
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Priority to CN202010115286.3A priority Critical patent/CN113376949B/en
Priority to PCT/CN2021/075977 priority patent/WO2021169789A1/en
Publication of CN113376949A publication Critical patent/CN113376949A/en
Priority to US17/491,460 priority patent/US11856338B2/en
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Publication of CN113376949B publication Critical patent/CN113376949B/en
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/54—Accessories
    • G03B21/56—Projection screens
    • G03B21/58—Projection screens collapsible, e.g. foldable; of variable area

Abstract

The application discloses a laser projection system and a method for controlling ascending and descending of a projection screen, and belongs to the technical field of laser projection. The laser projection system includes: projection display module, projection screen, control assembly and pivot. When the laser projection system is not used, the rotating shaft is driven to rotate through the control assembly, so that the projection screen is wound on the rotating shaft, the occupied space of the projection screen is effectively reduced, and the whole occupied space of the laser projection system is further reduced. In addition, the projection display module can adjust the projection frame rate of multiple frames of images to be projected to adjust the lifting speed of the effective content area when the pixel line number ratio of the effective content area in one frame of images to be projected currently projected is determined to be inconsistent with the real-time lifting process parameter of the projection screen in the process that the control component drives the projection screen to lift, so that the boundary of the effective content area and the boundary of the unfolded projection screen coincide as much as possible in the process that the projection screen lifts and lowers.

Description

Laser projection system and method for controlling ascending and descending of projection screen
Technical Field
The present disclosure relates to the field of laser projection technologies, and in particular, to a laser projection system and a method for controlling ascending and descending of a projection screen.
Background
The laser projection system comprises a projection screen and a laser projection host, and is used for realizing the functions of video playing and the like.
The laser projection host adopts a laser light source which has the advantages of good monochromaticity, high brightness and the like, so that the projection picture also has richer colors, better brightness and contrast and higher projection picture quality. However, the traditional projection curtain adopts a diffuse reflection light emitting mode, has low gain, and cannot well restore the picture advantages brought by a laser light source.
Therefore, laser projection devices are usually equipped with a dedicated optical screen, such as a fresnel screen, comprising a plurality of optical films, which have a high gain and are particularly suitable for ultra-short-focus projection of reflections of obliquely incident light. With the increase of the projection size, the optical screen is also increased to match with the picture, the size of the optical film is also increased, and as the size of the optical film is larger but the rigidity of the optical film is limited, a back plate or a frame with the same area is generally required to be arranged for supporting, so that the fixation of the optical film is realized, the flatness of the optical film is also required to be maintained (which is very important for the display of the projection picture), and the whole projection screen also occupies a larger plane space.
The support structure of the projection screen is usually fixed on the wall surface or on the support medium by means of screw drilling, which is a kind of destructive fixation. Once the fixing device is fixedly installed, the device is not suitable to be moved.
Moreover, for the ultra-short-focus laser projection system, the requirement of a projection ratio is met, the position and the distance between the laser projection host and the projection screen are fixed, if the projection host is displaced, debugging and resetting are needed again, and the debugging difficulty is increased due to the particularity of ultra-short-focus imaging. Therefore, the whole laser projection system in the prior art occupies a large space, and brings many limitations to the use of users.
Disclosure of Invention
The embodiment of the application provides a laser projection system with a retractable projection screen and good user experience, and a method for controlling the ascending and descending of the projection screen, wherein the technical scheme is as follows:
in one aspect, a laser projection system is provided, comprising: the projection display device comprises a projection display module, a projection screen, a control assembly and a rotating shaft, wherein the control assembly is connected with the projection display module, and the rotating shaft is fixedly connected with one end of the projection screen;
the control assembly is configured to: driving the rotating shaft to rotate so as to drive the projection screen to be wound on the rotating shaft or unfolded from the rotating shaft, so that the projection screen is lifted;
the projection display module is used for: in the process that the control assembly drives the projection screen to ascend and descend, multiple frames of images to be projected are projected to the plane where the projection screen is located in sequence; each frame of the image to be projected comprises an effective content area and an ineffective content area, and the effective content areas in at least two frames of the image to be projected in the plurality of frames of the image to be projected are different;
simultaneously acquiring real-time lifting process parameters of the projection screen and the pixel line number ratio of the effective content area in the currently projected frame of the image to be projected;
and when the real-time lifting process parameters of the projection screen are inconsistent with the pixel line number ratio of the effective content area, adjusting the projection frame rate of the plurality of frames of images to be projected.
In another aspect, a method for controlling the ascending of a projection screen is provided, which is applied to the above laser projection system, where the laser projection system includes: the projection display device comprises a projection display module, a projection screen, a control assembly and a rotating shaft, wherein the control assembly is connected with the projection display module, and the rotating shaft is fixedly connected with one end of the projection screen; the method comprises the following steps:
after the laser projection system receives a starting-up instruction, the control component drives the rotating shaft to rotate so as to drive the projection screen to be wound and unfolded from the rotating shaft, so that the projection screen ascends, and meanwhile, the projection display module sequentially projects a plurality of frames of images to be projected to the surface where the projection screen is located; each frame of the image to be projected comprises an effective content area and an ineffective content area, and the effective content areas in at least two frames of the image to be projected in the plurality of frames of the image to be projected are different;
the projection display module simultaneously obtains real-time lifting process parameters of the projection screen and the pixel line number ratio of the effective content area in the currently projected frame of the image to be projected;
and the projection display module adjusts the projection frame rate of the plurality of frames of images to be projected when the real-time lifting process parameters of the projection screen are inconsistent with the pixel line number ratio of the effective content area.
In another aspect, a method for controlling the descending of a projection screen is provided, which is applied to the above laser projection system, and the laser projection system includes: the projection display device comprises a projection display module, a projection screen, a control assembly and a rotating shaft, wherein the control assembly is connected with the projection display module, and the rotating shaft is fixedly connected with one end of the projection screen; the method comprises the following steps:
after the laser projection system receives a shutdown instruction, the control component drives the rotating shaft to rotate so as to drive the projection screen to be wound on the rotating shaft, so that the projection screen descends, and meanwhile, the projection display module sequentially projects a plurality of frames of images to be projected to the surface where the projection screen is located; each frame of the image to be projected comprises an effective content area and an ineffective content area, and the effective content areas in at least two frames of the image to be projected in the plurality of frames of the image to be projected are different;
the projection display module simultaneously obtains real-time lifting process parameters of the projection screen and the pixel line number ratio of the effective content area in the currently projected frame of the image to be projected;
and the projection display module adjusts the projection frame rate of the plurality of frames of images to be projected when the real-time lifting process parameters of the projection screen are inconsistent with the pixel line number ratio of the effective content area.
The beneficial effects brought by the technical scheme provided by the embodiment of the application at least comprise:
when the laser projection system is not used, the rotating shaft is driven to rotate through the control assembly, so that the projection screen is wound on the rotating shaft, the occupied space of the projection screen is effectively reduced, and the whole occupied space of the laser projection system is further reduced. And the projection display module can adjust the projection frame rate of a plurality of frames of images to be projected to adjust the lifting speed of the effective content area when determining that the pixel line number ratio of the effective content area in the currently projected image to be projected is not consistent with the real-time lifting process parameter of the projection screen in the process of driving the projection screen to lift by the control component, so that the pixel line number ratio of the effective content area is the same as the real-time lifting process parameter of the projection screen as much as possible, and further, in the process of lifting the projection screen, the boundary of the effective content area is overlapped with the boundary of the unfolded projection screen as much as possible, thereby improving the display effect of the projection content displayed by the projection screen in the process of lifting the projection screen.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a block diagram of a laser projection system provided by an embodiment of the present application;
FIG. 2 is a schematic diagram of an image to be projected according to an embodiment of the present disclosure;
FIG. 3 is a schematic diagram of a laser projection system according to an embodiment of the present disclosure;
FIG. 4 is a side view of the laser projection system shown in FIG. 3;
FIG. 5 is a schematic diagram of another laser projection system provided in an embodiment of the present application;
FIG. 6 is a diagram illustrating an effect of a projection screen in a fully extended state according to an embodiment of the present disclosure;
FIG. 7 is a diagram illustrating an effect of another projection screen provided in an embodiment of the present application in a fully unfolded state;
FIG. 8 is a schematic diagram of a laser projection system according to an embodiment of the present disclosure;
FIG. 9 is a block diagram of another laser projection system through which embodiments of the present application may pass;
FIG. 10 is a graph of the velocity of a projection screen as it rises according to an embodiment of the present disclosure;
FIG. 11 is a graph illustrating the speed of a projection screen as it descends according to an embodiment of the present disclosure;
fig. 12 is a flowchart of a method for controlling the lifting of a projection screen according to an embodiment of the present disclosure;
fig. 13 is a flowchart of another method for controlling the lifting of a projection screen according to an embodiment of the present disclosure.
Detailed Description
To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
Referring to fig. 1, fig. 1 is a block diagram of a laser projection system according to an embodiment of the present disclosure. The laser projection system 00 may be a laser television, and the laser projection system 00 may include: projection display module 10, projection screen 20, control assembly 30, and hinge 40.
The control assembly 30 may be coupled to the projection display module 10, and, for example, a communication link may be established between the control assembly 30 and the projection display module 10. The communication connection means a connection established by wire or wirelessly. For example, the control component 30 and the projection display module 10 may be communicatively connected by RS232 communication.
The rotation shaft 40 is fixedly connected to one end of the projection screen 20. The control assembly 30 may also be coupled to a shaft 40. The control assembly 40 is configured to: the rotating shaft 40 is driven to rotate to drive the projection screen 20 to wind around the rotating shaft 40 or unwind from the rotating shaft 40, so that the projection screen 20 is lifted. In the embodiment of the present application, since the projection screen 20 can be wound on the rotating shaft 40 or unwound from the rotating shaft 40, when the laser projection system 00 is used, the rotating shaft 40 is driven to rotate by the control component 30, so that the projection screen 20 is unwound from the rotating shaft 40; when the laser projection system 00 is not used, the control component 30 drives the rotating shaft 40 to rotate, so that the projection screen 20 is wound on the rotating shaft 40, the occupied space of the projection screen 20 is effectively reduced, and the whole occupied space of the laser projection system is further reduced.
The projection display module 10 is configured to: in the process that the control component 30 drives the projection screen to ascend and descend, multiple frames of images to be projected are projected to the plane of the projection screen 20 in sequence; wherein, each frame of the image to be projected comprises an effective content area and an ineffective content area. For example, please refer to fig. 2, fig. 2 is a schematic diagram of an image to be projected according to an embodiment of the present application. The image to be projected includes: an effective content area 01 and an ineffective content area 02. The pixel value of each pixel in the invalid content area 02 is 0, that is, the image located in the invalid content area 02 is a black image. The image in the effective content area 01 may be a black image or a color image, for example, when the image in the effective content area 01 is a color image, the effective content area 01 includes at least pixels having a pixel value greater than 0.
It should be noted that the effective content areas in at least two frames of the images to be projected in the plurality of frames of images to be projected are different. In an implementation manner, the number of pixel lines in the effective content area in any two frames of images to be projected in the plurality of frames of images to be projected is different, and the difference value between the number of pixel lines in the effective content area in any two adjacent frames of images to be projected is the same, for example, the number of pixel lines in the effective content area in the 1 st frame of image to be projected is 1 line, the number of pixel lines in the effective content area in the 2 nd frame of image to be projected is 2 lines, and the number of pixel lines in the effective content area in the 3 rd frame of image to be projected is 3 lines. In another implementation manner, the multiple frames of images to be projected may be divided into multiple groups of images to be projected, the number of pixel lines in the effective content area in each group of images to be projected is the same, and the number of pixel lines in the effective content area in any two adjacent image groups to be projected is different, for example, the 1 st image to be projected and the 2 nd image to be projected are in the same group, the 3 rd image to be projected and the 4 th image to be projected are in the same group, the number of pixel lines in the effective content area of the 1 st image to be projected is 1 line, the number of pixel lines in the effective content area of the 2 nd image to be projected is 1 line, the number of pixel lines in the effective content area of the 3 rd image to be projected is 2 lines, and the number of pixel lines in the effective content area of the 4 th image to be projected is 2 lines.
The projection display module 10 is further configured to: in the process that the control component 30 drives the projection screen 20 to ascend and descend, the real-time ascending and descending process parameters of the projection screen 20 and the pixel line number ratio of an effective content area in a frame of a currently projected image to be projected are obtained at the same time; when the pixel line number ratio of the effective content area is not consistent with the real-time lifting process parameter of the projection screen 20, adjusting the projection frame rate of the multi-frame image to be projected, so that the pixel line number ratio of the effective content area is as same as the real-time lifting process parameter of the projection screen 20 as possible. The ratio of the number of pixel lines of the effective content area in the currently projected image to be projected is also referred to as the ratio of the number of pixel lines of the effective content area in the currently projected image to the total number of pixel lines of the image to be projected.
In the embodiment of the present application, when the projection display module 10 projects multiple frames of images to be projected onto the projection screen 20, in order to enable the effective content area (i.e. the projection content displayed on the projection screen 20) to have the effect of moving up and down along with the movement of the projection screen 20, the projection display module 10 needs to process multiple frames of images to be projected in real time before the projection screen 20 moves up and down or during the movement of the projection screen 20. For example, assuming that when the control component 30 drives the projection screen 20 to ascend and descend at a constant speed, and the ascending and descending speed of the projection screen 20 is the ideal ascending and descending speed of the projection screen 20, the projection display module 10 may process multiple frames of images to be projected based on the ideal ascending and descending speed of the projection screen 20.
In order to enable the projection content displayed on the projection screen 20 to have a better display effect during the lifting process of the projection screen 20, it is necessary to ensure that the lifting speed of the effective content area is the same as the lifting speed of the projection screen 20 during the projection process of the projection display module 10. In general, if the frame rate of the projection display module 10 projecting multiple frames of images to be projected onto the projection screen 20 is fixed, the lifting speed of the projection content displayed on the projection screen 20 is also constant, but the control module 30 is difficult to drive the projection screen 20 to lift in a constant speed manner during the driving of the projection screen 20 to lift, and there may be a problem that the boundary of the effective content area does not coincide with the boundary of the expanded projection screen. Therefore, in the embodiment of the present application, the projection display module 10 needs to adjust the projection frame rate of multiple frames of images to be projected based on the pixel line count ratio of the effective content area in the currently projected image to be projected and the real-time ascending and descending progress parameter of the projection screen 20, so as to adjust the ascending and descending speed of the effective content area, so that the real-time ascending and descending progress parameter of the projection screen 20 is the same as possible as the pixel line count ratio of the effective content area, and further, in the process of ascending and descending the projection screen 20, the boundary of the effective content area coincides with the boundary of the expanded projection screen as possible.
In summary, the laser projection system provided in the embodiment of the present application includes: projection display module, projection screen, control assembly and pivot. When the laser projection system is not used, the rotating shaft is driven to rotate through the control assembly, so that the projection screen is wound on the rotating shaft, the occupied space of the projection screen is effectively reduced, and the whole occupied space of the laser projection system is further reduced. And the projection display module can adjust the projection frame rate of a plurality of frames of images to be projected to adjust the lifting speed of the effective content area when determining that the pixel line number ratio of the effective content area in the currently projected image to be projected is not consistent with the real-time lifting process parameter of the projection screen in the process of driving the projection screen to lift by the control component, so that the pixel line number ratio of the effective content area is the same as the real-time lifting process parameter of the projection screen as much as possible, and further, in the process of lifting the projection screen, the boundary of the effective content area is overlapped with the boundary of the unfolded projection screen as much as possible, thereby improving the display effect of the projection content displayed by the projection screen in the process of lifting the projection screen.
In an embodiment of the present application, please refer to fig. 3 and fig. 4, where fig. 3 is a schematic structural diagram of a laser projection system provided in the embodiment of the present application, and fig. 4 is a side view of the laser projection system shown in fig. 3. The laser projection system 00 may further include: the box 50, the projection display module 10, the control assembly 30 and the rotating shaft 40 are all located in the box 50. When the projection screen 20 is fully wound around the shaft 40 (i.e., the projection screen 20 is in a fully retracted state), the projection screen 20 is also located in the box 50. In this way, the occupied space of the projection screen 20 can be further reduced, and the overall occupied space of the laser projection system 00 can be further reduced.
In the embodiment of the present application, the projection display module 10 needs to simultaneously obtain the pixel line count ratio of the effective content area in one frame of image to be projected currently projected by the projection display module 10 and the real-time elevation progress parameter of the projection screen 20 in the process that the control component 30 drives the projection screen 20 to elevate. The projection display module 10 may directly calculate the ratio of the number of pixel lines of the effective content area based on the number of pixel lines of the effective content area in the currently projected frame of image to be projected.
An implementation for acquiring real-time elevation process parameters of projection screen 20 for projection display module 10. In the present application, the real-time ascending and descending process parameters of the projection screen 20 are used to characterize: the real-time progress of the projection screen 20 is made when the control unit 30 normally drives the projection screen 20 to ascend or descend. It should be noted that, when the control unit 30 drives the projection screen 20 to ascend or descend normally, the ascending or descending speed of the projection screen 20 is not constant. The control component 30 may obtain the real-time lifting process parameter of the projection screen 20, and then send the real-time lifting process parameter of the projection screen 20 to the projection display module 10, so that the projection display module 10 may obtain the real-time lifting process parameter of the projection screen 20. It should be noted that there are various ways for the control component 30 to obtain the real-time ascending and descending process parameters of the projection screen 20, and the embodiment of the present application is schematically illustrated by taking the following two realizable ways as examples:
in a first alternative implementation, the control component 30 may determine a ratio of the current unfolded width of the projection screen 20 to the maximum unfolded width of the projection screen 20 as a real-time lifting progress parameter of the projection screen 20.
For example, please refer to fig. 5, fig. 5 is a schematic structural diagram of another laser projection system provided in the embodiment of the present application. The laser projection system 00 may further include: a cartridge 50, a plurality of reference structures 60 and a detector 70. The spindle 40 of the laser projection system 00 is located within the housing 50. The detector 70 may be on the shaft 40 and aligned with the plurality of reference structures 60. The reference structures 60 are located at the edge of the projection screen and are sequentially arranged along the lifting direction x of the projection screen 20, and it should be noted that the reference structures 60 are arranged at equal intervals, that is, when the projection screen 20 is in the fully unfolded state, the distances between any two adjacent reference structures are the same. Since the plurality of reference structures 60 are arranged at equal intervals, after the control unit 30 determines the number of reference structures 60 located outside the box 50, the control unit 30 can determine the current expansion width of the projection screen 20.
In the present application, the detector 70 is used to: detects the number of reference structures 60 located outside the cartridge 50 and sends the number of reference structures 60 located outside the cartridge 50 to the control assembly 30. The control assembly is used for: the number of reference structures 60 located outside the box 50 is received and the current deployed width of the projection screen 20 is determined based on the number of reference structures 60 located outside the box 50.
It should be noted that, because there are many possible implementations of the structure of the plurality of reference structures 60 in the present application, there are also many ways in which the detector 70 detects the number of reference structures 60 located outside the cartridge, and the present embodiment is schematically illustrated in the following two cases as examples.
In a first situation, please refer to fig. 6, where fig. 6 is an effect diagram of a projection screen in a fully unfolded state according to an embodiment of the present application. The plurality of reference structures 60 on the edge of the projection screen 20 may include: the first reference structure 601 and the second reference structure 602 are arranged at intervals, and the reflectivity of the first reference structure 601 is different from the reflectivity of the second reference structure 602. For example, the first reference structure 601 and the second reference structure 602 may be two reflection patterns with different reflectivities. For example, the first reference structure 601 may be a white pattern and the second reference structure 602 may be a black pattern.
In this case, the detector 70 may be a light sensor for emitting light, and receiving light. Illustratively, the detector 70 is configured to: emitting detection light to the plurality of reference structures 60; receiving detection light rays reflected by a plurality of reference structures, and generating a detection square wave signal based on the received detection light rays; based on this detected square wave signal, the number of first reference structures 601 and second reference structures 602 located outside the cartridge body 50 is determined.
In the embodiment of the present application, since the reflectivity of the first reference structure 601 is different from the reflectivity of the second reference structure 602, after the detector 70 emits the detection light to the plurality of reference structures 60, the intensity of the detection light reflected by the first reference structure 601 is different from the intensity of the detection light reflected by the second reference structure 602. Thus, the detection light emitted through the plurality of reference structures 60 is received at the detector 70, and the detector 70 may generate a detection square wave signal including a first level signal and a second level signal which are distributed at intervals based on the received detection light. The first level signal is generated based on the detected light reflected by the first reference structure 601 and the second level signal is generated based on the detected light reflected by the second reference structure 602. The level of the first level signal is different from the level of the second level signal, and in a normal case, if the reflectivity of the first reference structure 601 is greater than the reflectivity of the second reference structure 602, the level of the first level signal is higher than the level of the second level signal; if the reflectivity of the first reference structure 601 is smaller than the reflectivity of the second reference structure 602, the level of the first level signal is lower than the level of the second level signal.
It should be noted that, since the first reference structure 601 and the second reference structure 602 are both reflective patterns and there is no gap between the adjacent first reference structure 601 and the second reference structure 602, after the detector 70 sends the number of the first reference structure 601 and the second reference structure 602 located outside the box 50 to the control component 30, the control component 30 may calculate the current unfolded width of the projection screen 20 based on the number of the first reference structure 601 and the second reference structure 602, the length of the first reference structure 601 and the length of the second reference structure 602. The length direction of the first reference structure 601 and the length direction of the second reference structure 602 are both parallel to the lifting direction of the projection screen 20.
For example, the control unit 30 may calculate the current expansion width of the projection screen 20 by a first expansion width calculation formula. The first expansion width calculation formula is:
h0＝n×L1+m×L2；
wherein h is0Is the current unfolded width of projection screen 20; n is the number of first reference structures 601 located outside the cartridge 50; l is1For the length of each first reference structure 601; m is the number of second reference structures 602 located outside the cartridge 50; l is2For the length of each second reference structure 602. It should be noted that the relationship between n and m is: n is m, or n is m ± 1.
In a second case, please refer to fig. 7, fig. 7 is an effect diagram of another projection screen provided in the embodiment of the present application in a fully unfolded state. The reference structure 60 on the edge of the projection screen 20 may include: a sensor connected to the detector 70. In the embodiment of the present application, each sensor may be communicatively coupled to the detector 70 by way of wireless communication.
In this case, the sensor is used to: when outside the cassette 50, a position signal is sent to the detector 70. The detector 70 is used to: based on the received position signals, the number of sensors located outside the cartridge 50 is determined.
In the embodiment of the present application, since the distance between any two adjacent sensors is the same, after the detector 70 transmits the number of sensors located outside the box 50 to the control assembly 30, the control assembly 30 may calculate the current developed width of the projection screen 20 based on the number of sensors located outside the box 50, the length of the sensors, and the distance between any two sensors. Wherein the length direction of the sensor is parallel to the lifting direction of the projection screen 20.
For example, the control unit 30 may calculate the current expansion width of the projection screen 20 by a second expansion width calculation formula. The second expansion width calculation formula is:
h0＝k×L3+(k－1)×L4；
wherein h is0Is the current unfolded width of projection screen 20; k is the number of sensors located outside the cartridge 50; l is3For each sensor length; l is4For any two transmissionsThe distance between the sensors.
It should be noted that, for the above two cases, the control component 30 can obtain the current expansion width of the projection screen 20, and further can determine the real-time lifting progress parameter of the projection screen 20.
In a second alternative implementation manner, please refer to fig. 8, and fig. 8 is a schematic structural diagram of another laser projection system provided in the embodiment of the present application. The laser projection system 00 further comprises: the motor 80 is driven. The drive motor 80 has a transmission shaft 801. The control assembly 30 in the laser projection system 00 can be connected to the driving motor 80, the transmission shaft 801 of the driving motor 80 can be connected to the rotating shaft 40, and the control assembly 30 can rotate by controlling the transmission shaft 801 of the driving motor 80 to drive the rotating shaft 40 to rotate, so as to drive the projection screen 20 to go up and down.
Alternatively, the driving motor 80 may be a stepping motor, which is a motor that drives the transmission shaft 801 to rotate step by step at a fixed angle (generally referred to as a stepping angle). In general, in the case where the model of the stepping motor is determined, the step angle of the stepping motor is also determined. For example, if the stepping angle of the stepping motor is 7.5 °, when the stepping motor drives the transmission shaft 801 to rotate once, the transmission shaft 801 needs to perform 48 pitch angles of 360 °/7.5 °.
In this case, the control unit 30 may determine, as the real-time ascending and descending process parameter of the projection screen 20, a ratio of the number of advance angles currently performed by the transmission axis 801 to the number of step angles that the transmission axis 801 needs to perform during the switching between the fully expanded state and the fully retracted state of the projection screen 20.
In the present embodiment, the number of advance angles performed by the transmission axis 801 can be represented by the pulse amount of the pulse signal. For example, the laser projection system 00 may further include: the pulse encoder 90, the control module 30 in the laser projection system 00 can also be connected to the pulse encoder 90, and the pulse encoder 90 can be connected to the transmission shaft 801 of the driving motor 80. For example, the pulse encoder 90 may be sleeved on the transmission shaft 801, so that when the transmission shaft 801 rotates, the pulse encoder 90 can detect the number of the step angles performed by the transmission shaft 801 to generate a corresponding pulse signal, so that the pulse amount of the pulse signal generated by the pulse encoder can represent the number of the step angles performed by the transmission shaft 801.
In this case, the pulse encoder 90 is configured to: the first pulse signal is generated according to the number of currently performed step angles of the drive shaft 801. The control assembly 30 is also configured to: and determining the pulse quantity ratio of the first pulse signal and the second pulse signal as a real-time lifting process parameter of the projection screen 20. The second pulse signal is used for characterizing: the number of pitch angles of execution of the transmission shaft 801 of the driving motor 80 during switching of the projection screen 20 between the fully expanded state and the fully retracted state.
For example, in the case where the type of the pulse encoder 80 is determined, the pulse amount of the pulse signal output from the pulse encoder 80 is fixed when the transmission shaft 801 of the driving motor 80 rotates once, and therefore, the control unit 30 may acquire the pulse amount of the first pulse signal and the pulse amount of the second pulse signal.
For example, if the pulse amount of the pulse signal output from the pulse encoder 80 is 360 degrees and the step angle of the driving motor 80 is 7.5 degrees when the transmission shaft 801 of the driving motor 80 makes one rotation, the relationship between the pulse amount m of the pulse signal and the number s of step angles performed by the transmission shaft 801 can be determined as follows: m is 7.5 × s. Since the number of pitch angles that the transmission axis 801 needs to perform during switching between the fully expanded state and the fully retracted state of the projection screen 20 can be determined by the maximum expansion width of the projection screen 20, the pulse amount of the second pulse signal can be calculated from the relationship between the pulse amount of the pulse signal and the number of advancement angles that the transmission axis 801 performs.
It should be noted that, through the two optional implementation manners, the projection display module 10 may obtain the real-time lifting process parameter of the projection screen 20.
In this application, after the projection display module 10 simultaneously obtains the pixel line count ratio of the effective content area in the currently projected one frame of image to be projected and the real-time lifting process parameter of the projection screen 20, if the projection display module 10 determines that the pixel line count ratio of the effective content area is consistent with the real-time lifting process parameter of the projection screen 20, the projection display module 10 does not need to adjust the projection frame rate of the multiple frames of image to be projected, and does not need to adjust the lifting speed of the projection screen 20 through the control component 30. If the projection display module 10 determines that the pixel line count ratio of the effective content area is not consistent with the real-time lifting process parameter of the projection screen 20, the projection display module 10 needs to adjust the projection frame rate of multiple frames of images to be projected, or adjust the lifting speed of the projection screen 20 through the control component 30.
In this embodiment, when the projection display module 10 determines that the pixel line count ratio of the effective content area is inconsistent with the real-time ascending and descending process parameter of the projection screen 20, the projection display module 10 needs to detect whether the absolute value of the difference between the pixel line count ratio of the effective content area and the real-time ascending and descending process parameter of the projection screen 20 is smaller than the difference threshold.
If the projection display module 10 detects that the absolute value of the difference between the pixel line count ratio of the effective content area and the real-time ascending/descending process parameter of the projection screen 20 is smaller than the difference threshold, the projection display module 10 needs to adjust the projection frame rate of the multiple frames of images to be projected so as to adjust the ascending/descending speed of the effective content area.
If the projection display module 10 detects that the absolute value of the difference between the pixel line count ratio of the effective content area and the real-time ascending and descending process parameter of the projection screen 20 is not less than the difference threshold, the projection display module 10 needs to send instruction information for adjusting the ascending and descending speed of the projection screen 20 to the control component 30, so as to adjust the ascending and descending speed of the projection screen 20 through the control component 30.
And adjusting the projection frame rate of a plurality of frames of images to be projected by the projection display module 10. For example, if the projection display module 10 determines that the pixel line number of the effective content area is greater than the real-time ascending and descending process parameter of the projection screen 20 during the ascending process of the projection screen 20, and the ascending speed of the effective content area is too fast, the projection display module 10 reduces the projection frame rate of multiple frames of images to be projected, so as to reduce the ascending speed of the effective content area; when the projection display module 10 determines that the ratio of the number of pixel lines in the effective content area is smaller than the real-time lifting process parameter of the projection screen 20, and the lifting speed of the effective content area is too slow, the projection display module 10 increases the projection frame rate of multiple frames of images to be projected so as to increase the lifting speed of the effective content area. If the projection display module 10 determines that the pixel line number proportion of the effective content area is greater than the real-time lifting process parameter of the projection screen 20 and the falling speed of the effective content area is too slow in the process of descending the projection screen 20, the projection display module 10 increases the projection frame rate of the multi-frame image to be projected so as to increase the falling speed of the effective content area; when the projection display module 10 determines that the pixel line number ratio of the effective content area is smaller than the real-time lifting process parameter of the projection screen 20, and the falling speed of the effective content area is too fast, the projection display module 10 reduces the projection frame rate of the multi-frame image to be projected so as to reduce the falling speed of the effective content area.
The projection display module 10 adjusts the lifting speed of the projection screen 20 through the control component 30. For example, if the projection display module 10 determines that the pixel line count ratio of the effective content area is greater than the real-time ascending and descending process parameter of the projection screen 20 during the ascending process of the projection screen 20, the ascending speed of the projection screen 20 is too slow, the projection display module 10 needs to send first indication information for increasing the ascending speed of the projection screen 20 to the control component 30, and after the control component 30 receives the first indication information, the control component 30 increases the ascending speed of the projection screen 20; when the projection display module 10 determines that the pixel line number ratio of the effective content area is smaller than the real-time ascending and descending process parameter of the projection screen 20, the ascending speed of the projection screen 20 is too fast, the projection display module 10 needs to send second indication information for reducing the ascending speed of the projection screen 20 to the control component 30, and after the control component 30 receives the second indication information, the control component 30 reduces the ascending speed of the projection screen 20. If the projection display module 10 determines that the pixel line count ratio of the effective content area is greater than the real-time ascending and descending process parameter of the projection screen 20 in the descending process of the projection screen 20, the descending speed of the projection screen 20 is too fast, the projection display module 10 needs to send third indication information for reducing the descending speed of the projection screen 20 to the control component 30, and after the control component 30 receives the third indication information, the control component 30 reduces the descending speed of the projection screen 20; when the projection display module 10 determines that the pixel line number ratio of the effective content area is smaller than the real-time lifting process parameter of the projection screen 20, the lowering speed of the projection screen 20 is too slow, the projection display module 10 needs to send fourth indication information for increasing the lowering speed of the projection screen 20 to the control component 30, and after the control component 30 receives the fourth indication information, the control component 30 increases the lowering speed of the projection screen 20.
In the embodiment of the present application, the control module 30 in the laser projection system 00 can control the lifting speed of the projection screen 20 by controlling the rotation speed of the transmission shaft 801 of the driving motor 80. For example, when the lifting speed of the projection screen 20 needs to be reduced, the control component 30 may send a control signal for reducing the rotation speed of the transmission shaft 801 to the driving motor 80 to reduce the lifting speed of the projection screen 20; when the lifting speed of the projection screen 20 needs to be increased, the control component 30 may send a control signal for increasing the rotation speed of the transmission shaft 801 to the driving motor 80, so as to increase the lifting speed of the projection screen 20. In the present application, when the driving motor 80 is a stepping motor, since the stepping motor is an open-loop control motor that converts an electrical pulse signal into an angular displacement, the rotation speed of the transmission shaft 801 is in positive correlation with the frequency of the electrical pulse signal output by the stepping motor, and therefore, the control unit 30 can control the frequency of the electrical pulse signal output by the stepping motor to control the rotation speed of the transmission shaft 801.
In the application, the projection display module 10 needs to periodically and simultaneously acquire the pixel line count ratio of the effective content area in one frame of currently projected image to be projected and the real-time lifting progress parameter of the projection screen 20, and when the acquisition period is sufficiently small, the lifting speed of the effective content area can be infinitely close to the lifting speed of the projection screen 20 by adjusting the projection frame rate of multiple frames of images to be projected or the lifting speed of the projection screen 20, so that the boundary of the effective content area and the boundary of the unfolded projection screen coincide as much as possible, thereby improving the display effect of the projection content displayed by the projection screen in the lifting process of the projection screen.
Optionally, the control assembly 30 is configured to: in the process of driving the projection screen 20 to ascend and descend, acquiring real-time ascending and descending process parameters of the projection screen 20 and preset ascending and descending process parameters of the projection screen 20 at the same time; if the real-time lifting process parameter of the projection screen 20 is different from the preset lifting process parameter of the projection screen 20, the lifting speed of the projection screen 20 is adjusted to adjust the lifting process of the projection screen 20. In the present application, the preset lifting process parameters of the projection screen 20 are used to characterize: the real-time process of the projection screen 20 is performed when the control unit 30 drives the projection screen 20 to ascend or descend at a constant speed. In this way, in the lifting process of the projection screen 20, the control component 30 can adjust the lifting process of the projection screen 20 to drive the projection screen 20 to lift in a constant speed driving manner as much as possible, so as to further improve the overlapping degree between the boundary of the effective content area and the boundary of the expanded projection screen.
It should be noted that, reference may be made to corresponding parts in the foregoing embodiments for the manner of acquiring the real-time ascending and descending process parameters of the projection screen 20 by the control component 30, and details are not described herein again.
Implementation of the control component 30 to obtain the preset lifting process parameters of the projection screen 20. Assuming that the control module 30 drives the projection screen 20 to ascend and descend at a constant speed, the ascending and descending speed of the projection screen 20 is the ideal ascending and descending speed of the projection screen 20, and the preset process parameter of the projection screen 20 can be obtained based on the ideal ascending and descending speed of the projection screen 20. For example, the preset process parameters of the projection screen 20 may be: the ratio of the desired current deployed width of the projection screen 20 to the maximum deployed width of the projection screen 20, the control component 30 may obtain the desired current deployed width of the projection screen 20 based on the desired lifting speed of the projection screen 20. For example, the ideal current spreading width of the projection screen 20 is the product of the ideal lifting speed of the projection screen 20 and the current lifting time of the projection screen 20.
In another alternative implementation, if the control component drives the projection screen 20 at a constant speed, the preset process parameters of the projection screen 20 may also be: the ratio of the length of time currently in progress during the raising and lowering of the projection screen 20 to the desired total length of time when the raising and lowering of the projection screen 20 is completed.
It should be noted that the ideal total time length when the projection screen 20 is completely lifted is determined based on the ideal lifting speed of the projection screen 20 and the maximum spread width of the projection screen 20. For example, the total time period when the projection screen 20 is completely lifted is the ratio of the maximum spread width of the projection screen 20 to the ideal lifting speed of the projection screen 20.
Optionally, please refer to fig. 9, fig. 9 is a block diagram of another laser projection system according to an embodiment of the present application. The projection display module 10 in the laser projection system 00 may include: a video processing sub-module 101, a video control sub-module 102 and a projection sub-module 103. The video processing sub-module 101 is connected to the video control sub-module 102 and the projection sub-module 103, respectively. The control assembly 30 may include: a lifting control unit 301 and a lifting progress detection unit 302. The lifting control unit 301 is connected with the lifting process detection unit 302, the lifting control unit 301 is connected with the video control submodule 102, and the lifting process detection unit 302 is connected with the video control submodule 102.
The elevation control unit 301 is configured to drive the projection screen 20 to ascend and descend. The video processing submodule 101 is configured to process a plurality of frames of images to be projected. The projection submodule 103 is used for projecting a plurality of frames of images to be projected onto the plane of the projection screen 20.
The lifting process detection unit 302 is configured to obtain real-time lifting process parameters of the projection screen 20, and send the real-time lifting process parameters to the video control sub-module 102 and the lifting control unit 301.
The video control submodule 102 is configured to obtain a real-time lifting process parameter of the projection screen 20 and a pixel line count ratio of an effective content area in the image to be projected currently projected by the projection submodule 103 at the same time, and adjust a projection frame rate of multiple frames of images to be projected when the real-time lifting process parameter of the projection screen 20 is inconsistent with the pixel line count ratio of the effective content area.
The video control sub-module 102 is further configured to send, to the lifting control unit 301, indication information for adjusting the lifting speed of the projection screen 20 when the absolute value of the difference between the real-time lifting progress parameter of the projection screen 20 and the ratio of the number of pixel lines in the effective content area is not less than the difference threshold.
The elevation control unit 301 is configured to, after receiving the instruction information sent by the video control sub-module 102, adjust the elevation speed of the projection screen 20 based on the instruction information.
The lifting control unit 301 is further configured to obtain a real-time lifting process parameter of the projection screen 20 and a preset process parameter of the projection screen 20 at the same time, and adjust a lifting speed of the projection screen 20 when the real-time lifting process parameter of the projection screen 20 is inconsistent with the preset process parameter of the projection screen 20.
With reference to the above embodiments, the following embodiments schematically illustrate the laser projection system 00 as being powered on (i.e., the projection screen 20 needs to be raised) and powered off (i.e., the projection screen 20 needs to be lowered).
For the startup of the laser projection system 00, after the laser projection system 00 receives a startup instruction, the control component 30 in the laser projection system 00 may control the projection screen 10 to ascend, and the projection host 10 may project multiple frames of images to be projected onto the surface where the projection screen 10 is located. Then, the projection display module 10 needs to simultaneously obtain the pixel line count ratio of the effective content area in the currently projected frame of image to be projected and the real-time lifting process parameter of the projection screen 20; when the real-time ascending and descending process parameter of the projection screen 20 is not consistent with the pixel line number ratio of the effective content area, the projection host 10 needs to adjust the projection frame rate of a plurality of frames of images to be projected or the ascending speed of the projection screen 20.
For example, please refer to fig. 10, fig. 10 is a graph of a speed of a projection screen during ascending according to an embodiment of the present disclosure. Wherein, the abscissa represents the duration of operation, and the unit is: second; the ordinate represents height in units of: and (4) millimeter. The solid line represents the actual speed profile of the projection screen 20 during the ascent, and the dotted line represents the ideal speed profile of the projection screen 20 during the ascent, which is the speed at which the control unit 30 drives the projection screen 20 at a constant speed to perform the ascent.
In the process of ascending the projection screen 20, as shown in fig. 10, assuming that the ratio of the number of pixel lines in the effective content area is smaller than the real-time ascending and descending process parameter of the projection screen 20 at 0-t1, if the difference value between the ratio of the real-time ascending and descending process parameter of the projection screen 20 and the number of pixel lines in the effective content area is smaller than the difference threshold, the projection display module 10 increases the projection frame rate of multiple frames of images to be projected so as to increase the ascending speed of the effective content area; if the difference between the real-time ascending and descending process parameter of the projection screen 20 and the ratio of the number of pixel lines in the effective content area is not less than the difference threshold, the projection display module 10 needs to send second indication information to the control component 30, and after the control component 30 receives the second indication information, the control component 30 reduces the ascending speed of the projection screen 20. Assuming that the pixel line count ratio of the effective content area is greater than the real-time ascending and descending process parameter of the projection screen 20 at t1-t2, if the difference value between the pixel line count ratio of the effective content area and the real-time ascending and descending process parameter of the projection screen 20 is less than the difference threshold value, the projection display module 10 reduces the projection frame rate of the multi-frame image to be projected so as to reduce the ascending speed of the effective content area; if the difference between the pixel line count ratio of the effective content area and the real-time ascending and descending process parameter of the projection screen 20 is not less than the difference threshold, the projection display module 10 needs to send first indication information to the control component 30, and after the control component 30 receives the first indication information, the control component 30 increases the ascending speed of the projection screen 20.
For shutdown of the laser projection system 00, after the laser projection system 00 receives a shutdown instruction, the control component 30 in the laser projection system 00 may control the projection screen 10 to descend, and at the same time, the projection host 10 may project multiple frames of images to be projected onto the plane on which the projection screen 10 is located. Then, the projection display module 10 needs to obtain the pixel line count ratio of the effective content area and the real-time lifting process parameter of the projection screen 20 at the same time; when the real-time ascending and descending process parameters of the projection screen 20 are not consistent with the pixel line number ratio of the effective content area, the projection host 10 needs to adjust the projection frame rate of a plurality of frames of images to be projected or the descending speed of the projection screen 20.
For example, please refer to fig. 11, fig. 11 is a speed curve diagram of a projection screen descending according to an embodiment of the present application. Wherein, the abscissa represents the duration of operation, and the unit is: second; the ordinate represents height in units of: and (4) millimeter. The solid line represents the actual speed profile of the projection screen 20 as it descends, and the dotted line represents the ideal speed profile of the projection screen 20 as it descends, which is the speed at which the control unit 30 drives the projection screen 20 to descend at a constant speed.
In the process of descending the projection screen 20, as shown in fig. 11, assuming that the pixel line count ratio of the effective content area is greater than the real-time ascending and descending process parameter of the projection screen 20 at 0-t3, if the difference value between the pixel line count ratio of the effective content area and the real-time ascending and descending process parameter of the projection screen 20 is less than the difference threshold, the projection display module 10 reduces the projection frame rate of the multi-frame image to be projected so as to reduce the descending speed of the effective content area; if the difference between the pixel line count ratio of the effective content area and the real-time ascending and descending process parameter of the projection screen 20 is not less than the difference threshold, the projection display module 10 needs to send third indication information to the control component 30, and after the control component 30 receives the third indication information, the control component 30 reduces the descending speed of the projection screen 20. Assuming that the ratio of the pixel line number of the effective content area is smaller than the real-time ascending and descending process parameter of the projection screen 20 at t3-t4, if the difference value between the ratio of the real-time ascending and descending process parameter of the projection screen 20 and the pixel line number of the effective content area is smaller than the difference threshold, the projection display module 10 increases the projection frame rate of the multi-frame image to be projected so as to increase the descending speed of the effective content area; if the difference between the real-time ascending and descending process parameter of the projection screen 20 and the ratio of the number of pixel lines in the effective content area is not less than the difference threshold, the projection display module 10 needs to send fourth indication information to the control component 30, and after the control component 30 receives the fourth indication information, the control component 30 increases the descending speed of the projection screen 20.
In summary, the laser projection system provided in the embodiment of the present application includes: projection display module, projection screen, control assembly and pivot. When the laser projection system is not used, the rotating shaft is driven to rotate through the control assembly, so that the projection screen is wound on the rotating shaft, the occupied space of the projection screen is effectively reduced, and the whole occupied space of the laser projection system is further reduced. And the projection display module can adjust the projection frame rate of a plurality of frames of images to be projected to adjust the lifting speed of the effective content area when determining that the pixel line number ratio of the effective content area in the currently projected image to be projected is not consistent with the real-time lifting process parameter of the projection screen in the process of driving the projection screen to lift by the control component, so that the pixel line number ratio of the effective content area is the same as the real-time lifting process parameter of the projection screen as much as possible, and further, in the process of lifting the projection screen, the boundary of the effective content area is overlapped with the boundary of the unfolded projection screen as much as possible, thereby improving the display effect of the projection content displayed by the projection screen in the process of lifting the projection screen.
The embodiment of the application also provides a rising control method of the projection screen. The method for controlling the elevation of the projection screen is applied to the laser projection system 00 shown in fig. 1, 3, 5, 8, or 9. The laser projection system 00 may include: projection display module 10, projection screen 20, control assembly 30, and hinge 40. Referring to fig. 12, fig. 12 is a flowchart illustrating a method for controlling the ascending of a projection screen according to an embodiment of the present disclosure. The elevation control method of the projection screen may include:
step 1201, after the laser projection system receives a starting-up instruction, the control component drives the rotating shaft to rotate so as to drive the projection screen to be wound and unfolded from the rotating shaft, so that the projection screen ascends, and meanwhile, a plurality of frames of images to be projected are projected to the surface where the projection screen is located in sequence; each frame of image to be projected comprises an effective content area and an ineffective content area, and the effective content areas in at least two frames of images to be projected in the plurality of frames of images to be projected are different.
Step 1202, the projection display module simultaneously obtains real-time lifting process parameters of the projection screen and the pixel line number ratio of an effective content area in a currently projected frame of image to be projected.
Step 1203, when the real-time lifting process parameter of the projection screen is not consistent with the pixel line number ratio of the effective content area, the projection display module adjusts the projection frame rate of the multiple frames of images to be projected.
The embodiment of the application also provides a descending control method of the projection screen. The method for controlling the descent of the projection screen is applied to the laser projection system 00 shown in fig. 1, 3, 5, 8, or 9. The laser projection system 00 may include: projection display module 10, projection screen 20, control assembly 30, and hinge 40. Referring to fig. 13, fig. 13 is a flowchart illustrating a method for controlling a descending of a projection screen according to an embodiment of the present disclosure. The method for controlling the descent of the projection screen may include:
step 1301, after the laser projection system receives a shutdown instruction, the control component drives the rotating shaft to rotate so as to drive the projection screen to be wound on the rotating shaft, so that the projection screen descends, and meanwhile, multiple frames of images to be projected are projected to the surface where the projection screen is located in sequence; each frame of image to be projected comprises an effective content area and an ineffective content area, and the effective content areas in at least two frames of images to be projected in the plurality of frames of images to be projected are different.
Step 1302, the projection display module simultaneously obtains real-time lifting process parameters of the projection screen and a pixel line number ratio of an effective content area in a currently projected frame of the image to be projected.
And step 1303, when the real-time lifting process parameters of the projection screen are inconsistent with the pixel line number ratio of the effective content area, the projection display module adjusts the projection frame rate of multiple frames of images to be projected.
Optionally, the acquiring, by the projection display module, a real-time lifting process parameter of the projection screen includes: and receiving the real-time lifting process parameters of the projection screen sent by the control component. There are various ways for the control component to obtain the real-time lifting process parameters of the projection screen, and the following two optional implementation manners are taken as examples in the embodiment of the present application to schematically illustrate the method.
In a first optional implementation manner, the acquiring, by the control component, a real-time lifting process parameter of the projection screen includes: and the control component determines the ratio of the current expansion width of the projection screen to the maximum expansion width of the projection screen as a real-time lifting process parameter of the projection screen.
Optionally, the laser projection system further comprises: a cartridge, a plurality of reference structures, and a detector. The rotating shaft is located in the box body, the reference structure is located at the edge of the projection screen and is sequentially arranged along the lifting direction of the projection screen. The detector is used for detecting the number of reference structures positioned outside the box body;
the control assembly determines the ratio of the current expansion width of the projection screen to the maximum expansion width of the projection screen as a real-time lifting process parameter of the projection screen, and comprises the following steps:
the control assembly determines a current deployed width of the projection screen based on the number of reference structures located outside the enclosure detected by the detector.
In the embodiments of the present application, there are various ways in which the detector detects the number of reference structures located outside the cartridge, and the embodiments of the present application are described below by taking two cases as examples.
In a first case, the plurality of reference structures comprises: the first reference structures and the second reference structures are arranged at intervals, and the reflectivity of the first reference structures is different from that of the second reference structures. The detector detects the number of reference structures located outside the cartridge, including: the detector emits detection light to the plurality of reference structures; the detector receives the detection light rays reflected by the plurality of reference structures and generates a detection square wave signal based on the received detection light rays; the detector determines the number of first reference structures and second reference structures located outside the cartridge body based on detecting the square wave signal. The detection square wave signal comprises a first level signal and a second level signal which are distributed at intervals, the first level signal is generated based on detection light reflected by the first reference structure, and the second level signal is generated based on detection light reflected by the second reference structure.
In a second case, the reference structure comprises: a sensor connected to the detector. The sensor is adapted to send a position signal to the detector when outside the housing. The detector detects the number of reference structures located outside the cartridge, including: the detector determines the number of sensors located outside the cartridge body based on the received position signals.
In a second alternative implementation, the laser projection system further includes: a pulse encoder and a drive motor having a transmission shaft. The control assembly is connected with the pulse encoder and the driving motor, and a transmission shaft of the driving motor is connected with the pulse encoder and the rotating shaft. The control assembly is used for controlling the transmission shaft of the driving motor to rotate so as to drive the rotating shaft to rotate. The pulse encoder is used for generating a first pulse signal according to the number of the currently executed step angles of the transmission shaft.
The control component acquires real-time lifting process parameters of the projection screen, and the control component comprises the following steps: and the control component determines the pulse quantity ratio of the first pulse signal and the second pulse signal as a real-time lifting process parameter of the projection screen. Wherein the second pulse signal is used to characterize: the number of step angles that the axes perform is transmitted during the switching of the projection screen between the fully extended state and the fully retracted state.
Optionally, before adjusting the frame rate of projection of the plurality of frames of images to be projected, the method may further include: the projection display module detects whether the absolute value of the difference value of the real-time lifting process parameter of the projection screen and the pixel line number ratio of the effective content area is smaller than a difference value threshold value; if the absolute value of the difference value of the real-time lifting process parameter of the projection screen and the ratio of the pixel line number of the effective content area is smaller than the difference value threshold, adjusting the projection frame rate of a plurality of frames of images to be projected; and if the absolute value of the difference value of the real-time lifting process parameter of the projection screen and the pixel line number ratio of the effective content area is not less than the difference value threshold, sending indication information for adjusting the lifting speed of the projection screen to the control assembly.
Optionally, the method may further include: the control assembly simultaneously acquires real-time lifting process parameters of the projection screen and preset lifting process parameters of the projection screen in the process of driving the projection screen to lift; and when the real-time lifting process parameters of the projection screen are inconsistent with the preset lifting process parameters of the projection screen, adjusting the lifting process of the projection screen.
Optionally, the step 1203 may include: if the pixel line number ratio of an effective content area in a frame of image to be projected currently projected by the projection display module is greater than the real-time lifting process parameter of the projection screen, the projection display module reduces the projection frame rate of multiple frames of images to be projected; and if the pixel line number ratio of the effective content area in one frame of the image to be projected currently projected by the projection display module is smaller than the real-time lifting process parameter of the projection screen, the projection display module improves the projection frame rate of the multi-frame image to be projected.
Optionally, the step 1303 may include: if the pixel line number ratio of an effective content area in a frame of image to be projected currently projected by the projection display module is greater than the real-time lifting process parameter of the projection screen, the projection display module increases the projection frame rate of multiple frames of images to be projected; and if the pixel line number ratio of the effective content area in one frame of the image to be projected currently projected by the projection display module is smaller than the real-time lifting process parameter of the projection screen, reducing the projection frame rate of the multi-frame image to be projected by the projection display module.
It should be noted that, the ascending control method of the projection screen and the descending control method of the projection screen provided in the embodiments of the present application may be appropriately adjusted in sequence of steps, and the steps may also be increased or decreased according to the circumstances.
It should be noted that, in the above embodiments of the method for controlling the ascending of the projection screen and the method for controlling the descending of the projection screen, the connection relationship of the components in the laser projection system and the operation principle of the components can refer to the structural embodiments of the laser projection system. The embodiments of the present application are not described herein again.
In this application, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The term "plurality" means two or more unless expressly limited otherwise.
It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, where the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.
The above description is intended to be exemplary only, and not to limit the present application, and any modifications, equivalents, improvements, etc. made within the spirit and scope of the present application are intended to be included therein.

Claims (10)

1. A laser projection system, comprising: the projection display device comprises a projection display module, a projection screen, a control assembly and a rotating shaft, wherein the control assembly is connected with the projection display module, and the rotating shaft is fixedly connected with one end of the projection screen;
the control assembly is configured to: driving the rotating shaft to rotate so as to drive the projection screen to be wound on the rotating shaft or unfolded from the rotating shaft, so that the projection screen is lifted;
the projection display module is used for: in the process that the control assembly drives the projection screen to ascend and descend, multiple frames of images to be projected are projected to the plane where the projection screen is located in sequence; each frame of the image to be projected comprises an effective content area and an ineffective content area, and the effective content areas in at least two frames of the image to be projected in the plurality of frames of the image to be projected are different;
simultaneously acquiring real-time lifting process parameters of the projection screen and the pixel line number ratio of the effective content area in the currently projected frame of the image to be projected;
and when the real-time lifting process parameters of the projection screen are inconsistent with the pixel line number ratio of the effective content area, adjusting the projection frame rate of the plurality of frames of images to be projected.
2. The laser projection system of claim 1, wherein the control component is configured to send real-time elevation process parameters of the projection screen to the projection display module;
wherein, the real-time lift process parameter of projection screen includes: a ratio of a current unfolded width of the projection screen to a maximum unfolded width of the projection screen.
3. The laser projection system of claim 2, further comprising: the detection assembly is connected with the control assembly;
the rotating shaft is positioned in the box body, the reference structures are positioned at the edge of the projection screen and are sequentially arranged along the lifting direction of the projection screen;
the detector is used for: detecting the number of reference structures located outside the cassette;
the control assembly is configured to: determining a current unfolded width of the projection screen based on the number of reference structures located outside the housing detected by the detector.
4. The laser projection system of claim 1, further comprising: a pulse encoder and a driving motor having a transmission shaft;
the control assembly is connected with the pulse encoder and the driving motor, and a transmission shaft of the driving motor is connected with the pulse encoder and the rotating shaft;
the control assembly is configured to: the transmission shaft of the driving motor is controlled to rotate so as to drive the rotating shaft to rotate;
the pulse encoder is configured to: generating a first pulse signal according to the number of currently executed step angles of the transmission shaft;
the control assembly is further configured to: determining the pulse quantity ratio of the first pulse signal to the second pulse signal as a real-time lifting process parameter of the projection screen; wherein the second pulse signal is used to characterize: the number of pitch angles the transmission axis performs during switching of the projection screen between the fully extended state and the fully retracted state.
5. The laser projection system of any of claims 1 to 4, wherein the projection display module is configured to:
in the process that the control component drives the projection screen to ascend, if the pixel line number ratio of the effective content area is greater than the real-time ascending and descending process parameter of the projection screen, reducing the projection frame rate of the multiple frames of images to be projected; if the pixel line number ratio of the effective content area is smaller than the real-time lifting process parameter of the projection screen, improving the projection frame rate of the multi-frame image to be projected;
in the process that the control component drives the projection screen to descend, if the pixel line number ratio of the effective content area is greater than the real-time lifting process parameter of the projection screen, the projection frame rate of the multiple frames of images to be projected is increased; and if the pixel line number ratio of the effective content area is smaller than the real-time lifting process parameter of the projection screen, reducing the projection frame rate of the plurality of frames of images to be projected.
6. The laser projection system of any of claims 1 to 4, wherein the projection display module is configured to: before adjusting the projection frame rate of the plurality of frames of images to be projected, detecting whether the absolute value of the difference value of the real-time lifting process parameter of the projection screen and the pixel line number ratio of the effective content area is smaller than a difference threshold value;
if the absolute value of the difference value of the real-time lifting process parameter of the projection screen and the ratio of the pixel line number of the effective content area is smaller than the difference value threshold, adjusting the projection frame rate of the plurality of frames of images to be projected;
and if the absolute value of the difference value of the real-time lifting process parameter of the projection screen and the pixel line number ratio of the effective content area is not less than the difference value threshold, sending indication information for adjusting the lifting speed of the projection screen to the control assembly.
7. A laser projection system as claimed in any one of claims 1 to 4, wherein the control assembly is configured to: in the process of driving the projection screen to lift, simultaneously acquiring real-time lifting process parameters of the projection screen and preset lifting process parameters of the projection screen;
and when the real-time lifting process parameters of the projection screen are inconsistent with the preset lifting process parameters of the projection screen, adjusting the lifting process of the projection screen.
8. A laser projection system as claimed in any one of claims 1 to 4, further comprising: a box body;
the projection display module, the control assembly and the rotating shaft are all located in the box body, and when the projection screen is in a complete retraction state, the projection screen is located in the box body.
9. A method for controlling the ascending of a projection screen, which is applied to the laser projection system according to any one of claims 1 to 8, the laser projection system comprising: the projection display device comprises a projection display module, a projection screen, a control assembly and a rotating shaft, wherein the control assembly is connected with the projection display module, and the rotating shaft is fixedly connected with one end of the projection screen; the method comprises the following steps:
after the laser projection system receives a starting-up instruction, the control component drives the rotating shaft to rotate so as to drive the projection screen to be wound and unfolded from the rotating shaft, so that the projection screen ascends, and meanwhile, the projection display module sequentially projects a plurality of frames of images to be projected to the surface where the projection screen is located; each frame of the image to be projected comprises an effective content area and an ineffective content area, and the effective content areas in at least two frames of the image to be projected in the plurality of frames of the image to be projected are different;
the projection display module simultaneously obtains real-time lifting process parameters of the projection screen and the pixel line number ratio of the effective content area in the currently projected frame of the image to be projected;
and the projection display module adjusts the projection frame rate of the plurality of frames of images to be projected when the real-time lifting process parameters of the projection screen are inconsistent with the pixel line number ratio of the effective content area.
10. A method for controlling lowering of a projection screen, which is applied to the laser projection system according to any one of claims 1 to 8, the laser projection system comprising: the projection display device comprises a projection display module, a projection screen, a control assembly and a rotating shaft, wherein the control assembly is connected with the projection display module, and the rotating shaft is fixedly connected with one end of the projection screen; the method comprises the following steps:
after the laser projection system receives a shutdown instruction, the control component drives the rotating shaft to rotate so as to drive the projection screen to be wound on the rotating shaft, so that the projection screen descends, and meanwhile, the projection display module sequentially projects a plurality of frames of images to be projected to the surface where the projection screen is located; each frame of the image to be projected comprises an effective content area and an ineffective content area, and the effective content areas in at least two frames of the image to be projected in the plurality of frames of the image to be projected are different;
the projection display module simultaneously obtains real-time lifting process parameters of the projection screen and the pixel line number ratio of the effective content area in the currently projected frame of the image to be projected;
and the projection display module adjusts the projection frame rate of the plurality of frames of images to be projected when the real-time lifting process parameters of the projection screen are inconsistent with the pixel line number ratio of the effective content area.
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PCT/CN2021/075977 WO2021169789A1 (en) 2020-02-25 2021-02-08 Projection system, and startup operation method and shutdown operation method for same
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