Projection equipment

Abstract

The present application discloses a projection device, belonging to the field of projection technology. The projection device includes: an optical engine and a projection screen; the projection screen includes a base, a control mechanism, a screen, guide rollers, a transmission mechanism, and a drive motor; the control mechanism is fixed to the base and is used to support the screen; the base has two first guide grooves positioned opposite each other, the two ends of the guide roller are respectively located in the two first guide grooves, the transmission mechanism is rotatably limited on the base, and the drive motor is fixed to the base, the output shaft of the drive motor is connected to the transmission mechanism, and the transmission mechanism is also connected to the guide roller. In the embodiment of the present application, the drive motor can drive the guide roller to move within the first guide groove through the transmission mechanism, so that the guide roller can push the screen to achieve the purpose of limiting the pitch angle of the screen, thereby correcting the position of the screen and avoiding distortion, blurring, and distortion of the image displayed on the screen, thereby improving the display effect of the projection screen.

Description

[0001] The embodiments of this application claim priority to Chinese patent application number 202010340787.1, filed on April 26, 2020, with the invention name “Projection Device”, the entire contents of which are incorporated by reference into the embodiments of this application. Technical Field

[0002] The embodiments of the present application relate to the field of projection technology, and in particular to a projection device. Background Art

[0003] With the continuous development of technology, projection equipment is increasingly used in people's work and life. Currently, projection equipment mainly consists of an optical engine and a projection screen. The light outlet of the optical engine faces the projection screen, emitting a light beam to the projection screen, which receives the light beam and displays the image.

[0004] In related technologies, such as Figure 1 As shown, the projection screen 1 includes a screen 11, a rolling assembly 12, a lifting assembly 13, and a base 14. The rolling assembly 12 is fixed to the base 14, and the screen 11 is fixedly connected to the rolling assembly 12. At the same time, the screen 11 is also fixedly connected to the end of the lifting assembly 13 away from the rolling assembly 12. The lifting assembly 13 and the rolling assembly 12 can control the unfolding and curling of the screen 11. The lifting assembly 13 includes multiple sets of brackets, each set of brackets includes a first support rod 131 and a second support rod 132. The three movable joints between the first end of the first support rod 131 and the base 14, between the second end of the first support rod 131 and the first end of the second support rod 132, and between the second end of the second support rod 132 and the screen 11 are all rotatably connected. The multiple sets of brackets can control the unfolding of the screen 11.

[0005] However, because the three movable joints each have clearances, when the lifting assembly 13 is lifted to unfold the screen 11, the reverse force from the screen 11 can easily cause the lifting assembly 13 to tilt due to the clearances reserved at the three movable joints. Furthermore, the three movable joints are susceptible to wear, further exacerbating the tilt of the lifting assembly 13. Consequently, when the lifting assembly tilts, the screen 11 also tilts, causing the image displayed on the screen 11 to become distorted, blurry, and blurry, thereby affecting the display quality of the projection screen 1. Summary of the Invention

[0006] The embodiment of the present application provides a projection device that can solve the problem that the screen included in the projection device is prone to tilt. The technical solution is as follows:

[0007] A projection device, comprising:

[0008] an optical engine, the optical engine being used to emit a light beam;

[0009] A projection screen comprising a base, a control mechanism, a screen, a guide roller, a transmission mechanism and a drive motor;

[0010] The control mechanism is fixed on the base, and the control mechanism is used to support the screen, and the screen is used to receive the light beam when supported;

[0011] The base has two first guide grooves positioned opposite to each other, and the two ends of the guide roller are respectively located in the two first guide grooves. The transmission mechanism is rotatably limited on the base. The drive motor is fixed to the base, and the output shaft of the drive motor is connected to the transmission mechanism. The transmission mechanism is also connected to the guide roller. The drive motor can drive the guide roller to move in the first guide groove through the transmission mechanism to press against the screen piece and limit the pitch angle of the screen piece.

[0012] Optionally, the transmission mechanism includes a worm and a worm wheel;

[0013] The length direction of the worm is parallel to the length direction of the first guide groove, and the worm is rotatably limited on the base. The worm is connected to the output shaft of the drive motor, and the drive motor can drive the worm to rotate along its own circumferential direction;

[0014] The worm wheel is axially limited at the first end of the guide roller, and the worm is engaged with the worm wheel.

[0015] Optionally, the axial direction of the output shaft of the drive motor is colinear with the length direction of the worm, and the output shaft of the drive motor is fixedly connected to the end of the worm.

[0016] Optionally, the transmission mechanism further includes a first gear and a second gear, the first gear being fixedly connected to the output shaft of the drive motor along the axial direction, the second gear being fixedly connected to one end of the worm along the axial direction, and the first gear being meshed with the second gear.

[0017] Optionally, the axial direction of the output shaft of the drive motor is parallel to the length direction of the worm, and the first gear and the second gear are both cylindrical gears.

[0018] Optionally, the axial direction of the output shaft of the drive motor is perpendicular to the length direction of the worm, and the first gear and the second gear are both bevel gears.

[0019] Optionally, the transmission mechanism includes a lead screw;

[0020] The length direction of the lead screw is parallel to the length direction of the first guide groove, and the lead screw is rotatably limited on the base, and the lead screw is threadedly connected to the first end of the guide roller;

[0021] The output shaft of the driving motor is connected to the lead screw, and the driving motor can drive the lead screw to rotate.

[0022] Optionally, the transmission mechanism also includes a third gear and a rack, the third gear is axially limited at the second end of the guide roller, the rack is fixed on the base, the length direction of the rack is parallel to the length direction of the first guide groove, and is engaged with the third gear.

[0023] Optionally, the length direction of the first guide groove is horizontal.

[0024] Optionally, the control mechanism includes a curling assembly and a lifting assembly;

[0025] The curling assembly is limited on the base, the first side of the curtain piece is fixedly connected to the curling assembly, and the curling assembly can rotate along its own circumferential direction to control the curtain piece to be retracted;

[0026] The first end of the lifting assembly is fixedly connected to the base, and the second end of the lifting assembly is fixedly connected to a second side of the curtain piece opposite to the first side. The lifting assembly can control the unfolding of the curtain piece.

[0027] The beneficial effects of the technical solutions provided by the embodiments of the present application may include at least:

[0028] When the control mechanism props up the screen, the drive motor drives the transmission mechanism, achieving automatic control, thereby facilitating the movement of the guide roller. Because the guide roller can move within the first guide groove, once the guide roller contacts the screen and continues to move within the first guide groove, it pushes and presses the screen against it, defining its pitch angle. This allows the guide roller to correct the screen's position, preventing distortion and blurring of the image displayed on the screen, thereby improving the display quality of the projection screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] Figure 1This is a partially enlarged structural diagram of a projection screen provided by the related art;

[0031] Figure 2 This is a schematic diagram of the side view structure of a projection screen provided by the related art;

[0032] Figure 3 This is a side view structural diagram of another projection screen provided by the related art;

[0033] Figure 4 This is a schematic structural diagram of a projection device provided in an embodiment of the present application;

[0034] Figure 5 This is a schematic structural diagram of a transmission mechanism provided in an embodiment of the present application;

[0035] Figure 6 This is a structural diagram of another transmission mechanism provided in an embodiment of the present application;

[0036] Figure 7 This is a structural diagram of another transmission mechanism provided in an embodiment of the present application;

[0037] Figure 8 This is a schematic diagram of the exploded structure of another transmission mechanism provided in an embodiment of the present application;

[0038] Figure 9 This is a structural diagram of another transmission mechanism provided in an embodiment of the present application;

[0039] Figure 10 This is a schematic structural diagram of a projection screen provided by an embodiment of the present application;

[0040] Figure 11 This is a schematic side view of the structure of a projection screen provided in an embodiment of the present application;

[0041] Figure 12 This is a schematic side view of the structure of a projection screen provided in an embodiment of the present application;

[0042] Figure 13 is a schematic side view of another projection screen provided in an embodiment of the present application;

[0043] Figure 14 It is a structural schematic diagram of a projection device provided in an embodiment of the present application.

[0044] Reference numerals:

[0045] Related technologies:

[0046] 1: Projection screen; 11: Screen; 12: Curling assembly; 13: Lifting assembly; 14: Base;

[0047] 131: first support rod; 132: second support rod; 133: connecting shaft.

[0048] Examples of this application:

[0049] 1: Optical engine; 2: Projection screen; 3: Storage unit;

[0050] 21: base; 22: control mechanism; 23: screen piece; 24: guide roller; 25: transmission mechanism; 26: drive motor; 31: light-transmitting area; 32: opening;

[0051] 211: first guide groove; 221: curling assembly; 222: lifting assembly; 251: worm; 252: worm wheel; 253: first gear; 254: second gear; 255: lead screw; 256: third gear; 257: rack; 258: nut; 259: sleeve;

[0052] 2510: guide shaft; 2511: fourth gear; 2512: fifth gear; 2221: crossbeam; 2222: first support rod; 2223: second support rod. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the following will explain the situation where the screen is cut or twisted in combination with related technologies.

[0054] In the related art, the lifting assembly 13 includes multiple sets of brackets, such as Figure 1 As shown, each bracket set further includes a connecting shaft 133; the second end of the first support rod 131 is provided with a first connecting groove, and the first end of the second support rod 132 extends into the first connecting groove. The second end of the first support rod 131 and the first end of the second support rod 132 are rotatably connected via the connecting shaft 133. The two groove walls of the first connecting groove and the side wall of the first end of the second support rod 132 are both provided with connecting holes. The connecting shaft 133 passes through the connecting holes on the two groove walls and the connecting hole on the second support rod 132 to achieve rotatable connection between the first support rod 131 and the second support rod 132.

[0055] Typically, an assembly gap is provided between the wall of the connecting hole in the slot wall and the connecting shaft 133. For example, the gap between the wall of the connecting hole in the slot wall and the connecting shaft 133 is less than or equal to 0.2 mm. This makes it easy for the second support rod 132 to tilt under external forces, causing the relative position between the second end of the first support rod 131 and the first end of the second support rod 132 to change, and also causing the straight line between the center points of the two connecting holes in the first connecting slot to form an angle with the axial direction of the connecting shaft 133. Furthermore, when the second support rod 132 tilts, it causes the screen 11 to tilt forward or backward.

[0056] The inclination angle of the second support rod 132 is equal to the angle between the straight line where the center points of the two connecting holes on the first connecting groove are located and the axial direction of the connecting shaft 133. The maximum angle between the straight line where the center points of the two connecting holes on the first connecting groove are located and the axial direction of the connecting shaft 133 is calculated according to the following formula:

[0057] α=tan -1 D / B

[0058] Among them, α is the maximum angle between the straight line where the center points of the two connecting holes on the first connecting groove are located and the axial direction of the connecting shaft 133, D is the gap between the hole wall of the connecting hole and the connecting shaft 133, and B is the distance between the two groove walls of the first connecting groove.

[0059] It should be noted that, since the position of the curling assembly 12 is fixed, the position of the side of the screen 11 connected to the curling assembly 12 will not change. Figure 2 As shown, the second support rods 132 included in the multiple sets of brackets may all tilt away from the screen 11, so that one side of the screen 11 connected to the multiple sets of brackets will tilt backward, causing the screen 11 to tilt backward; Figure 3 As shown, the second support rods 132 included in the multiple sets of brackets may also tilt closer to the screen 11, so that one side of the screen 11 connected to the multiple sets of brackets will tilt forward, thereby causing the screen 11 to tilt forward.

[0060] It should also be noted that the contact areas between the first support rod 131 and the connecting shaft 133, the first support rod 131 and the second support rod 132, and the second support rod 132 and the connecting shaft 133 are all prone to wear, thereby further aggravating the degree of forward or backward tilt of the screen 11.

[0061] Based on the above description, in the related art, there is a problem that the screen 11 included in the projection screen 1 is prone to tilting forward or backward, which causes the screen 11 to be unable to normally receive the light beam emitted by the optical engine, resulting in problems such as distortion, blurring and distortion of the displayed image.

[0062] Next, the embodiments of the present application will be described in further detail with reference to the accompanying drawings.

[0063] Figure 4 A schematic diagram illustrating the structure of a projection device according to an embodiment of the present application is shown. Figure 5 The schematic diagram of the structure of a transmission mechanism of an embodiment of the present application is illustrated. Figure 4 and Figure 5As shown, the projection device includes: an optical engine 1 and a projection screen 2. The optical engine 1 is configured to emit a light beam. The projection screen 2 includes a base 21, a control mechanism 22, a screen 23, a guide roller 24, a transmission mechanism 25, and a drive motor 26. The control mechanism 22 is fixed to the base 21 and configured to support the screen 23. The screen 23 is configured to receive the light beam when supported. The base 21 has two first guide grooves 211 positioned opposite each other. The ends of the guide roller 24 are respectively located in the two first guide grooves 211. The transmission mechanism 25 is rotatably restrained on the base 21. The drive motor 26 is fixed to the base 21. The output shaft of the drive motor 26 is connected to the transmission mechanism 25. The transmission mechanism 25 is also connected to the guide roller 24. The drive motor 26 can drive the guide roller 24 to move within the first guide grooves 211 via the transmission mechanism 25 to press against the screen 23 and limit the pitch angle of the screen 23.

[0064] In the embodiment of the present application, when the control mechanism 22 props up the screen 23, the drive motor 26 drives the transmission mechanism 25 to operate, achieving automatic control of the transmission mechanism 25, thereby facilitating the transmission mechanism 25 to drive the guide roller 24 to move. Because the guide roller 24 is movable within the first guide groove 211, after the guide roller 24 contacts the screen 23 and continues to move within the first guide groove 211, it pushes and presses the screen 23 against it, thereby defining the pitch angle of the screen 23. This allows the guide roller 24 to correct the position of the screen 23, thereby preventing distortion, blurring, and other issues in the image displayed on the screen 23, thereby improving the display quality of the projection screen 2.

[0065] It should be noted that the projection screen 2 also includes a control system, which is electrically connected to the drive motor 26. When the position of the screen 23 needs to be corrected, the control system sends a start command to the drive motor 26 to start operating. The drive motor 26 then drives the guide roller 24 via the transmission mechanism 25 to adjust the pitch angle of the screen 23. When the pitch angle of the screen 23 is adjusted to the target pitch angle, the control system sends a stop command to the drive motor 26 to stop operating, thereby stopping the transmission mechanism 25. This allows the guide roller 24 to remain pressed against the screen 23, thereby limiting the pitch angle of the screen 23. Therefore, the control system can start and stop the drive motor 26 based on the actual position of the screen 23, thereby ensuring the accuracy of the movement of the guide roller 24. The target pitch angle of the screen 23 is the angle between the plane in which the screen 23 lies and the vertical line, without causing unnecessary tilt. For example, the target pitch angle of the screen 23 is 0 degrees, 5 degrees, or the like.

[0066] The base 21 is used to be fixedly connected to the support body to achieve the fixation of the projection screen 2. The support body is the support surface of the fixed bracket or the wall surface of the wall. Of course, in other embodiments, the support body is a support cabinet or a table, etc., as long as the projection screen 2 can be fixedly supported.

[0067] Optionally, optical engine 1 is an ultra-short-throw optical engine. In this way, the distance from optical engine 1 to the plane of projection screen 2 is set to a relatively short distance to achieve a miniaturized design of the entire laser projection device. Optical engine 1 includes a light source, an optical-mechanical system, and a lens. The optical-mechanical system includes a DMD (Digital Micromirror Device) board and the DMD. The light source is used to emit a light beam to the optical-mechanical system. The DMD board included in the optical-mechanical system is used to provide a driving signal to the DMD, so that the DMD can modulate the light beam emitted by the light source based on the driving signal and emit the modulated light beam to the lens. The light beam is then emitted through the lens to the projection screen 2 for display.

[0068] Optionally, in an embodiment of the present application, the projection device is a laser ultra-short-throw projection device, the ultra-short-throw optical engine is a DLP (Digital Light Processing) projection optical engine, and the lens included in the optical engine 1 is an ultra-short-throw projection lens. Furthermore, the screen 23 of the projection screen 2 is an optical screen 23, such as a rollable Fresnel optical screen or a flexible black screen. Such an optical screen 23 has higher optical gain than a traditional screen, can restore the brightness and contrast of the light beam as much as possible, and can achieve a high degree of flatness through the control and stretching of the control mechanism 22, making it suitable for ultra-short-throw projection imaging applications.

[0069] In some embodiments, as shown in the figures, the guide roller 24 is an elongated structure, so as to press against the screen piece 23 along its length, thereby limiting the position of the screen piece 23 over a wide range. Of course, the guide roller 24 can also have other shapes, as long as it can press against the screen piece 23 and limit the pitch angle of the screen piece 23.

[0070] The cross-sectional shape of the guide roller 24 is circular or polygonal. A guide roller 24 with a circular cross-sectional shape is easier to process, and its surface is smoother, less likely to damage the screen 23. A guide roller 24 with a polygonal cross-sectional shape is more stable and less likely to wobble. When the cross-sectional shape of the guide roller 24 is polygonal, for example, the cross-sectional shape is square, hexagonal, or other shapes.

[0071] In some embodiments, the base 21 includes two support plates, and the two first guide grooves 211 are respectively provided on the two support plates, so that the two ends of the guide roller 24 can pass through the two first guide grooves 211 respectively.

[0072] The first guide groove 211 is shaped like an elongated strip or an ellipse, though other shapes are acceptable as long as the guide roller 24 can move within the first guide groove 211. The width of the first guide groove 211 is slightly larger than the diameter or side length of the cross section of the guide roller 24. This allows the guide roller 24 to move more flexibly within the first guide groove 211. The length of the first guide groove 211 is set based on the maximum tilting amount of the screen piece 23 along the length of the first guide groove 211. The length of the first guide groove 211 is slightly larger than the maximum tilting amount of the screen piece 23 along the length of the first guide groove 211 to avoid interference with the guide roller 24 when it limits the pitch angle of the screen piece 23.

[0073] In some embodiments, the length of the first guide groove 211 is horizontal or at an acute angle to the horizontal. For example, when the guide roller 24 moves within the first guide groove 211, it has a horizontal component, thereby compressing or pushing the screen piece 23 in the horizontal direction, thereby adjusting or eliminating the angle between the screen piece 23 and the vertical direction, thereby limiting the pitch angle of the screen piece 23 when the guide roller 24 is pressed against the screen piece 23.

[0074] It should be noted that the target pitch angle of the screen 23 is set according to the angle of the light beam emitted by the optical engine 1 or other factors, and the angle of the first guide groove 211 is further set according to the target pitch angle of the screen 23. As long as the guide roller 24 moving along the length direction of the first guide groove 211 can limit the pitch angle of the screen 23 to the target pitch angle, this embodiment of the present application is not limited to this.

[0075] In some embodiments, a lubricating member that fits tightly against the inner wall of each first guide groove 211 is provided on the inner wall of each first guide groove 211. This can reduce the friction between the guide roller 24 and the first guide groove 211, and enhance the smoothness of the movement of the guide roller 24 in the first guide groove 211. At the same time, it can facilitate improving the movement accuracy of the guide roller 24.

[0076] In the embodiment of the present application, the transmission mechanism 25 is a transmission mechanism 25 including a worm gear 252 and a worm 251, or a transmission mechanism 25 including a lead screw 255. Of course, it can also be other transmission mechanisms 25, as long as it can drive the guide roller 24 to move within the first guide groove 211. When the transmission mechanism 25 is a transmission mechanism 25 including a worm gear 252 and a worm 251, the axial direction of the output shaft of the drive motor 26 and the length direction of the worm 251 can be collinear, parallel, perpendicular, or the angle between the two is acute. When the transmission mechanism 25 is a transmission mechanism 25 including a lead screw 255, the axial direction of the output shaft of the drive motor 26 and the length direction of the lead screw 255 can also be collinear, parallel, perpendicular, or the angle between the two is acute.

[0077] Next, the transmission mechanism 25 including the worm wheel 252 and the worm 251 will be described in detail.

[0078] In some embodiments, as Figure 5 As shown, the transmission mechanism 25 includes a worm 251 and a worm wheel 252; the length direction of the worm 251 is parallel to the length direction of the first guide groove 211, and the worm 251 is rotatably limited on the base 21, and the worm 251 is connected to the output shaft of the drive motor 26, and the drive motor 26 can drive the worm 251 to rotate along its own circumferential direction; the worm wheel 252 is axially limited at the first end of the guide roller 24, and the worm 251 is engaged with the worm wheel.

[0079] In this way, after the driving motor 26 is started, it can drive the worm 251 to rotate, and then drive the worm wheel 252 engaged with it to roll along the length direction of the worm 251 through the worm 251. Since the worm wheel 252 is axially limited at the first end of the guide roller 24, the worm wheel 252 can drive the guide roller 24 to move along the length direction of the worm 251 when rolling. Furthermore, since the length direction of the worm 251 is parallel to the length direction of the first guide groove 211, it can ensure that the guide roller 24 moves along the length direction of the first guide groove 211 at the same time.

[0080] Optionally, two limiting sleeves are fixed to the base 21, one on each side of the helical teeth of the worm 251, and the two limiting sleeves are rotatable with the worm 251. In this way, the two limiting sleeves can support the worm 251 and ensure that the worm 251 rotates along its own circumferential direction. For example, lubricating oil is provided at the contact area between the worm 251 and the limiting sleeves to ensure flexibility during rotation of the worm 251.

[0081] Optionally, the worm gear 252 is fixedly connected to the first end of the guide roller 24. In this way, when the worm gear 252 rolls, it can drive the guide roller 24 to roll together. At the same time, the fixed connection between the worm gear 252 and the guide roller 24 can achieve smooth force transmission. Of course, in other embodiments, the worm gear 252 is rotatably limited to the first end of the guide roller 24. In this way, due to the rotatable connection between the worm gear 252 and the guide roller 24, when the worm gear 252 rolls along the length direction of the worm 251, it can keep the guide roller 24 in a translational state.

[0082] Next, when the transmission mechanism 25 includes the worm 251 and the worm wheel 252 , the relative positions of the axial direction of the output shaft of the drive motor 26 and the longitudinal direction of the worm 251 will be described.

[0083] In some embodiments, the axial direction of the output shaft of the drive motor 26 is collinear with the length direction of the worm 251, and the output shaft of the drive motor 26 is fixedly connected to the end of the worm 251. In this way, after the drive motor 26 is started, the output shaft rotates and can drive the worm 251 fixedly connected thereto to rotate together.

[0084] Optionally, the output shaft of the drive motor 26 and the end of the worm 251 are fixedly connected via a coupling, and of course they can also be fixedly connected in other ways.

[0085] In other embodiments, Figure 5 As shown, the axial direction of the output shaft of the drive motor 26 is parallel to the length direction of the worm 251. Optionally, the transmission mechanism 25 further includes a first gear 253 and a second gear 254. The first gear 253 is fixedly connected to the output shaft of the drive motor 26 along the axial direction, and the second gear 254 is fixedly connected to one end of the worm 251 along the axial direction, and the first gear 253 and the second gear 254 are meshed. In this embodiment, the first gear 253 and the second gear 254 are both cylindrical gears. Thus, after the drive motor 26 is started, it drives the first gear 253 to rotate, and the first gear 253 drives the meshed second gear 254 to rotate, and then the second gear 254 drives the worm 251 to rotate together. Furthermore, since the first gear 253 and the second gear 254 are both cylindrical gears, the axial direction of the first gear 253 is parallel to the axial direction of the second gear 254, so as to accommodate the situation where the axial direction of the output shaft of the drive motor 26 is parallel to the length direction of the worm 251.

[0086] Optionally, the first gear 253 and the second gear 254 are both spur gears, which have a strong load-bearing capacity and are easy to process and produce. In some embodiments, the first gear 253 and the second gear 254 are both helical gears, which have good gear meshing performance, relatively stable operation, and can ensure a more constant transmission ratio.

[0087] In yet other embodiments, the axial direction of the output shaft of the drive motor 26 is perpendicular to the length of the worm 251. Accordingly, the transmission mechanism 25 includes the first gear 253 and the second gear 254 of the above-described embodiment, wherein the first gear 253 and the second gear 254 are both bevel gears. In this way, the bevel gears can achieve transmission between two mutually perpendicular shafts.

[0088] Optionally, the first gear 253 and the second gear 254 are both straight bevel gears, which have the same or similar advantages as the above-mentioned straight cylindrical gears. In some embodiments, the first gear 253 and the second gear 254 are both helical bevel gears, which have the same or similar advantages as the above-mentioned helical cylindrical gears, and this embodiment of the present application will not be repeated.

[0089] In other embodiments, the axial direction of the output shaft of the drive motor 26 forms any acute angle with the longitudinal direction of the worm 251. Accordingly, the transmission mechanism 25 includes the first gear 253 and the second gear 254 of the above-mentioned embodiment, wherein the first gear 253 and the second gear 254 are both bevel gears. In this way, the parameters of the hammer gear are selected according to actual conditions to adapt to the angle between the axial direction of the output shaft of the drive motor 26 and the longitudinal direction of the worm 251.

[0090] It should be noted that, due to the different spatial environments in which the projection screen 2 is located, the fixed position of the drive motor 26 and the axial direction of the output shaft of the drive motor 26 will be adaptively adjusted according to the spatial environment in which the projection screen 2 is located. Accordingly, the positional relationship between the axial direction of the output shaft of the drive motor 26 and the length direction of the worm 251 will be adaptively changed, and the types of the first gear 253 and the second gear 254 can be selected from any of the above embodiments.

[0091] Next, the transmission mechanism 25 including the lead screw 255 will be described in detail.

[0092] In some embodiments, as Figure 6 As shown, the transmission mechanism 25 includes a screw 255; the length direction of the screw 255 is parallel to the length direction of the first guide groove 211, and the screw 255 is rotatably limited on the base 21, and the screw 255 is threadedly connected to the first end of the guide roller 24; the output shaft of the drive motor 26 is connected to the screw 255, and the drive motor 26 can drive the screw 255 to rotate.

[0093] In this way, after the drive motor 26 is started, it can drive the screw 255 to rotate, and then the screw 255 drives the guide roller 24 threadedly connected thereto to move along the length direction of the screw 255. Since the length direction of the screw 255 is parallel to the length direction of the first guide groove 211, it can ensure that the guide roller 24 moves along the length direction of the first guide groove 211 at the same time, and further enables the guide roller 24 to move toward the screen piece 23 and press against the screen piece 23.

[0094] In some embodiments, the first end of the guide roller 24 has a threaded hole, and one end of the lead screw 255 passes through the threaded hole and is threadedly connected to the guide roller 24. In this way, the guide roller 24 can be threadedly connected to the lead screw 255 based on the threaded hole it has.

[0095] Optionally, the transmission mechanism 25 further includes a guide shaft positioned on the base 21, with its length parallel to the length of the lead screw 255. Accordingly, the guide roller 24 has a guide hole through which the guide shaft passes, with its length being greater than the length of the guide hole. Thus, when the guide roller 24 moves along the length of the lead screw 255, the guide shaft serves as a guide and limiter, thereby improving the movement accuracy of the guide roller 24 and preventing unnecessary shaking of the guide roller 24.

[0096] In other embodiments, Figure 6 As shown, the transmission mechanism 25 further includes a nut 258, which is positioned at the first end of the guide roller 24. One end of the lead screw 255 is threadedly connected to the nut 258. Thus, the guide roller 24 can be threadedly connected to the lead screw 255 via the nut 258. Furthermore, for lead screws 255 of different specifications, the corresponding nuts 258 of different specifications can be replaced, allowing the guide roller 24 to be used in conjunction with lead screws 255 of different specifications.

[0097] Alternatively, as Figure 7 As shown, the transmission mechanism 25 further includes a sleeve 259, which is sleeved on the first end of the guide roller 24, and a nut 258 is fixedly connected to the sleeve 259. Thus, the slider can be connected to the guide roller 24 based on the sleeve 259. The sleeve 259 is fixedly connected to the first end of the guide roller 24 to achieve smooth transmission of force between the sleeve 259 and the guide roller 24. Of course, the sleeve 259 can also be rotatably connected to the first end of the guide roller 24, which is not limited in this embodiment of the present application.

[0098] Alternatively, as Figure 8As shown, when the transmission mechanism 25 includes a guide shaft 2510, the side wall of the nut 258 has a protrusion with a guide hole. The guide shaft 2510 passes through the guide hole, and the length of the guide shaft 2510 is greater than the length of the guide hole. In this way, when the nut 258 moves along the length of the lead screw 255, the guide shaft 2510 can serve as a guide and limiter, thereby improving the movement accuracy of the nut 258 and preventing unnecessary shaking of the nut 258.

[0099] Optionally, the transmission mechanism 25 further includes balls, and the nut 258 has a circuit connected to the internal thread. The balls are arranged in the spiral space and circuit formed by the nut 258 and the lead screw 255. When the nut 258 moves along the length of the lead screw 255, the balls can circulate in the spiral space and circuit. In this way, the balls can reduce the friction between the lead screw 255 and the nut 258, thereby enhancing the flexibility of the nut 258 when moving relative to the lead screw 255.

[0100] Next, in the case where the transmission mechanism 25 includes the lead screw 255 , the relative positions of the axial direction of the output shaft of the drive motor 26 and the longitudinal direction of the lead screw 255 will be described.

[0101] In some embodiments, the axial direction of the output shaft of the drive motor 26 is collinear with the length direction of the lead screw 255, and the output shaft of the drive motor 26 is fixedly connected to the end of the lead screw 255. The connection method between the drive motor 26 and the lead screw 255 is the same or similar to the connection method between the drive motor 26 and the worm 251, and will not be described in detail in this embodiment of the application.

[0102] In other embodiments, Figure 6 As shown, the axial direction of the output shaft of the drive motor 26 is parallel to the length direction of the lead screw 255. Optionally, the transmission mechanism 25 also includes a fourth gear 2511 and a fifth gear 2512. The fourth gear 2511 is fixedly connected to the output shaft of the drive motor 26 along the axial direction, and the fifth gear 2512 is fixedly connected to one end of the lead screw 255 along the axial direction. The fourth gear 2511 and the fifth gear 2512 are meshed. In this embodiment, the fourth gear 2511 and the fifth gear 2512 are both cylindrical gears. In this way, after the drive motor 26 is started, it drives the fourth gear 2511 to rotate, and the fourth gear 2511 drives the fifth gear 2512 meshed therewith to rotate, and then the fifth gear 2512 drives the lead screw 255 to rotate together. Furthermore, since the fourth gear 2511 and the fifth gear 2512 are both cylindrical gears, the axial direction of the fourth gear 2511 is parallel to the axial direction of the fifth gear 2512, so as to adapt to the situation where the axial direction of the output shaft of the drive motor 26 is parallel to the length direction of the lead screw 255.

[0103] In yet other embodiments, the axial direction of the output shaft of the drive motor 26 is perpendicular to the length of the lead screw 255. Accordingly, the transmission mechanism 25 includes the fourth gear 2511 and the fifth gear 2512 in the above-described embodiment, wherein the fourth gear 2511 and the fifth gear 2512 are both bevel gears. In this way, the bevel gears can achieve transmission between two mutually perpendicular shafts.

[0104] In yet other embodiments, the axial direction of the output shaft of the drive motor 26 forms any acute angle with the longitudinal direction of the lead screw 255. Accordingly, the transmission mechanism 25 includes the fourth gear 2511 and the fifth gear 2512 of the above-described embodiment, wherein both the fourth gear 2511 and the fifth gear 2512 are bevel gears. Thus, the parameters of the hammer gear are selected based on actual conditions to accommodate the angle between the axial direction of the output shaft of the drive motor 26 and the longitudinal direction of the worm 251.

[0105] In the embodiments of the present application, to ensure smooth movement of the guide roller 24, in some embodiments, a transmission mechanism 25 is also provided at the second end of the guide roller 24. When the transmission mechanism 25 includes a worm 251 and a worm gear 252, the worm gear 252 is axially constrained at the second end of the guide roller 24. When the transmission mechanism 25 includes a lead screw 255, the lead screw 255 is threadedly connected to the second end of the guide roller 24. Thus, the transmission mechanism 25 is provided at both ends of the guide roller 24, thereby controlling the synchronous movement of both ends of the guide roller 24 to ensure smooth movement of the entire guide roller 24. Accordingly, a control system is connected to two drive motors 26 located at each end of the guide roller 24. The control system controls the synchronous operation of the two drive motors 26, thereby enabling the two drive motors 26 to drive the guide roller 24 to move based on the two ends of the guide roller 24.

[0106] It should be noted that the two drive motors 26 can control the movement of the corresponding ends of the guide roller 24 in the same or different directions, that is, one end of the guide roller 24 can move toward the screen 23 and the other end can move away from the screen 23, or both ends of the guide roller 24 can move toward or away from the screen 23. Furthermore, the two drive motors 26 can control the movement of the corresponding ends of the guide roller 24 by the same or different amounts. In this way, when the screen 23 swings left and right, the swing directions and amounts on the left and right sides of the screen 23 will differ. Therefore, the activation timing and forward and reverse rotation of the two drive motors 26 can be controlled based on the different swing amounts and directions of the left and right sides of the screen 23, so that the corresponding ends of the guide roller 24 have different movement amounts and directions, thereby adapting to the actual correction of the left and right swing of the screen 23.

[0107] In other embodiments, Figure 9As shown, the transmission mechanism 25 also includes a third gear 256 and a rack 257. The third gear 256 is axially limited at the second end of the guide roller 24. The rack 257 is fixed on the base 21. The length direction of the rack 257 is parallel to the length direction of the first guide groove 211 and is engaged with the third gear 256.

[0108] Thus, when the drive motor 26 drives the guide roller 24 to roll based on the first end of the guide roller 24 via the worm gear 252, the third gear 256 is fixedly connected to the second end of the guide roller 24, so that the guide roller 24 drives the third gear 256 fixed to its second end to roll together, and the third gear 256 can then roll along the length of the rack 257 with which it meshes. Because the length of the rack 257 is parallel to the length of the first guide groove 211, the third gear 256 can be ensured to move along the length of the first guide groove 211 while rolling along the length of the rack 257. Furthermore, the third gear 256 can guide the guide roller 24, causing the second end of the guide roller 24 to move along the length of the first guide groove 211 synchronously with the first end.

[0109] When the drive motor 26 drives the guide roller 24 to move based on the first end of the guide roller 24 via the lead screw 255, the third gear 256 is rotatably mounted on the second end of the guide roller 24. Since the third gear 256 is also meshed with the rack 257, the movement of the guide roller 24 drives the third gear 256 mounted on its second end to move. At the same time, the rack 257 causes the third gear 256 to roll along the length of the rack 257, thereby enabling the third gear 256 to roll along the length of the meshed rack 257. Similarly, the third gear 256 can cause the second end of the guide roller 24 to move synchronously with the first end along the length of the first guide groove 211.

[0110] In some embodiments, as Figure 10 As shown, the control mechanism 22 includes a winding assembly 221 and a lifting assembly 222. The winding assembly 221 is fixedly attached to the base 21, and a first side of the screen 23 is fixedly connected to the winding assembly 221. The winding assembly 221 can rotate along its own circumferential direction to control the retraction of the screen 23. The lifting assembly 222 is fixedly attached to the base 21 at its first end, and fixedly attached to a second side of the screen 23 opposite the first side. The lifting assembly 222 can control the unfolding of the screen 23. Thus, when the projection device is in use, the lifting assembly 222 unfolds the screen 23 on the winding assembly 221 so that the screen can receive the light beam emitted by the optical engine 1. When the projection device is not in use, the winding assembly 221 can rotate along its own circumferential direction, thereby controlling the screen 23 to be rolled up on the winding assembly 221 to achieve the folding of the screen 23, thereby reducing the space occupied by the projection screen 2.

[0111] In some embodiments, a protective coating is provided on the back side of the screen piece 23, that is, the side of the screen piece 23 facing the control mechanism 22. This protective coating prevents the back side of the screen piece 23 from directly contacting the front side of the screen piece 23 when the screen piece 23 is in a curled state, thereby preventing the back side of the screen piece 23 from rubbing against the front side of the screen piece 23 and causing wear of the screen piece 23, thereby extending the service life of the screen piece 23. The protective coating is a coating composed of flexible particles or a colloidal coating, which is not limited in this embodiment of the present application. The protective coating is made of nanomaterials, which have excellent toughness, impact resistance, and thermal stability. Therefore, after the protective coating contacts the screen piece 23, it can also improve the flatness, wind resistance, and stability of the screen piece 23, and extend the service life of the screen piece 23.

[0112] In some embodiments, the guide roller 24 can be fixed or rotatable when pressed against the screen 23. When the guide roller 24 is rotatable, when the screen 23 is being rolled up by the winding assembly 221 or unrolled by the lifting assembly 222, the guide roller 24 can rotate, thereby reducing friction between the guide roller 24 and the screen 23 and preventing damage to the screen 23 caused by friction between the guide roller 24 and the screen 23.

[0113] Of course, when the winding assembly 221 controls the winding of the screen 23 or the lifting assembly 222 controls the unwinding of the screen 23, the guide roller 24 is controlled to move away from the screen 23 to prevent friction, thereby avoiding direct contact between the guide roller 24 and the screen 23. Optionally, during the unwinding of the screen 23 by the lifting assembly 222, the guide roller 24 is controlled to move away from the screen 23. When the screen 23 is unrolled on the control mechanism 22, the guide roller 24 is controlled to press against the screen 23 to define the pitch angle of the screen 23. During the unwinding of the screen 23 by the winding assembly 221, the guide roller 24 that was originally pressing against the screen 23 is moved away to avoid direct contact and friction between the guide roller 24 and the screen 23. Furthermore, the next time the projection screen 2 is used, the guide roller 24 is kept in its original position, and when the screen 23 is unrolled on the control mechanism 22 again, the guide roller 24 is controlled to continue to press against the screen 23.

[0114] It should be noted that in order to enable the guide roller 24 pressed against the curtain piece 23 to rotate around its own circumferential direction, the guide roller 24 and the worm gear 252, the guide roller 24 and the nut 258 included in the slider, or the guide roller 24 and the third gear 256 are all rotatably connected.

[0115] Of course, in some embodiments, the guide roller 24 is a drum-type guide roller 24, which includes a central shaft and a drum. Both ends of the central shaft are connected to a worm gear 252, a lead screw 255, or a third gear 256. The drum is rotatably mounted on the central shaft. In this way, the drum can rotate about the central shaft. The drum can be a hollow cylindrical drum or a hollow prismatic drum.

[0116] In some embodiments, a protective coating is provided on the guide roller 24. This coating prevents direct contact between the guide roller 24 and the screen sheet 23. This prevents the screen sheet 23 from being scratched by the rough surface of the guide roller 24 during relative motion between the screen sheet 23 and the guide roller 24, thereby extending the service life of the screen sheet 23. The protective coating is a coating composed of flexible particles or a gel-like coating.

[0117] In some embodiments, as Figure 10 As shown, when the guide roller 24 is in a strip-shaped structure, the length direction of the guide roller 24 is parallel to the axial direction of the winding assembly 221. In this way, the guide roller 24 presses the screen piece 23 tightly, thereby ensuring the flatness of the screen piece 23 and preventing the screen piece 23 from being twisted due to the presence of the guide roller 24.

[0118] In some embodiments, as Figure 11 As shown, when the intersection line between the curtain 23 and the curling assembly 221 is located horizontally between the first and second ends of the lifting assembly 222, the guide roller 24 compresses the curtain 23 on the side of the curtain 23 closest to the lifting assembly 222. Thus, when the intersection line between the curtain 23 and the curling assembly 221 is located between the first and second ends of the lifting assembly 222, because the first side of the curtain 23 is fixedly connected to the curling assembly 221 and the second side of the curtain 23 is fixedly connected to the second end of the lifting assembly 222, the intersection line between the curtain 23 and the curling assembly 221 is close to the first side of the curtain 23. As a result, the curtain 23 tilts toward the lifting assembly 222 relative to the vertical direction. Furthermore, the guide roller 24 on the side of the curtain 23 closest to the lifting assembly 222 can compress and push the curtain 23 away from the lifting assembly 222, thereby correcting the pitch angle of the curtain 23.

[0119] The intersection line between the curtain piece 23 and the curling assembly 221 is a line along the length direction of the curling assembly 221 formed at the position where the curtain piece 23 curled on the curling assembly 221 is about to leave the curling assembly 221, that is, a line along the length direction of the curling assembly 221 at the position where the unfolded portion of the curtain piece 23 is tangent to the curling assembly 221.

[0120] It should be noted that the lifting assembly 222 includes a crossbeam 2221 and multiple sets of brackets, each set of which includes a first support rod 2222 and a second support rod 2223. The first end of the first support rod 2222 is connected to the base 21, the second end of the first support rod 2222 is connected to the first end of the second support rod 2223, and the second end of the second support rod 2223 is connected to a side edge of the crossbeam 2221 along its length. Simultaneously, the other side edge of the crossbeam 2221 along its length is fixedly connected to the second side edge of the curtain panel 23, and the length of the crossbeam 2221 is equal to the length of the second side edge of the curtain panel 23. In this way, the crossbeam 2221 fully limits the length of the curtain panel 23, thereby ensuring the flatness of the curtain panel 23. In this embodiment, the second end of the lifting assembly 222 is specifically a side edge of the crossbeam 2221 fixedly connected to the curtain panel 23.

[0121] It should also be noted that if Figure 12 As shown, compared with Figure 5 The angle between the crossbeam 2221 and the horizontal plane will change due to the pulling force of the screen piece 23. In other words, the relative positions of the two side edges along the length direction of the crossbeam 2221 in the vertical direction will change due to the pulling force of the screen piece 23. Therefore, the positional relationship between the intersection line between the screen piece 23 and the curling assembly 221 and the first end and the second end of the lifting assembly 222 will change due to the change of the crossbeam 2221. Therefore, the crossbeam 2221 will affect the setting of the guide roller 24 to a certain extent.

[0122] In other embodiments, Figure 13 As shown, in the horizontal direction, when the intersection line between the screen 23 and the curling assembly 221 is located on the side close to the second end of the lifting assembly 222, the guide roller 24 compresses the screen 23 on the side of the screen 23 away from the lifting assembly 222. Thus, when the intersection line between the screen 23 and the curling assembly 221 is located on the side of the lifting assembly 222 close to the second end, because the first side of the screen 23 is fixedly connected to the curling assembly 221 and the second side of the screen 23 is fixedly connected to the second end of the lifting assembly 222, the intersection line between the screen 23 and the curling assembly 221 is close to the first side of the screen 23. As a result, the screen 23 tilts away from the lifting assembly 222 relative to the vertical direction. Furthermore, the guide roller 24 on the side of the screen 23 away from the lifting assembly 222 compresses and pushes the screen 23, bringing it closer to the lifting assembly 222, thereby correcting the pitch angle of the screen 23.

[0123] It should be noted that in both of the above embodiments, the tilt of the lifting assembly 222 is such that the second end of the lifting assembly 222 is tilted toward the direction where the screen piece 23 is located. When the tilt of the lifting assembly 222 is such that the second end of the lifting assembly 222 is tilted away from the screen piece 23, the intersection line between the screen piece 23 and the curling assembly 221 is located on the side closer to the first end of the lifting assembly 222. In this case, the guide roller 24 presses the screen piece 23 against the side of the screen piece 23 away from the lifting assembly 222.

[0124] It should also be noted that in the above two embodiments, the guide roller 24 corrects the pitch angle of the screen 23 in the area between the guide roller 24 and the second end of the lifting assembly 222. Therefore, the guide roller 24 is arranged near the curling assembly 221 to ensure that a large area of ​​the screen 23 can be adjusted.

[0125] In some embodiments, the guide rollers 24 include two guide rollers, each of which is designed with a gap between them, allowing the screen 23 to pass through the gap. Thus, in the horizontal direction, whether the intersection line between the screen 23 and the winding assembly 221 is between the first and second ends of the lifting assembly 222, or the intersection line between the screen 23 and the winding assembly 221 is located closer to the second end of the lifting assembly 222, either guide roller can push and press the screen 23, thereby correcting the pitch angle of the screen 23.

[0126] It should be noted that when the lifting assembly 222 rises to unfold the curtain piece 23, the curling assembly 221 can rotate clockwise or counterclockwise. When the central axis of the curling assembly 221 remains fixed, the intersection line between the clockwise rotating curling assembly 221 and the curtain piece 23 and the counterclockwise rotating curling assembly 221 and the curtain piece 23 will be at different positions. Therefore, the relationship between the intersection line between the curtain piece 23 and the curling assembly 221, the first end of the lifting assembly 222, and the second end of the lifting assembly 222 will be different.

[0127] In some embodiments, the projection screen 2 further comprises a rollable substrate, to which the screen piece 23 is adhered. A plurality of reinforcing ribs are provided on a side of the rollable substrate away from the screen piece 23, wherein the length direction of each reinforcing rib is not parallel to the longitudinal direction of the rollable substrate. A first side of the rollable substrate is fixedly connected to a rollable assembly 221, and a second side of the rollable substrate opposite to the first side is fixedly connected to a lifting assembly 222. The rollable assembly 221 is capable of rolling up the rollable substrate, and the lifting assembly 222 is capable of unfolding the rollable substrate. When the rollable substrate is unfolded, the support screen piece 23 is kept in a flat state.

[0128] In this way, the multiple reinforcing ribs enhance the strength of the rollable substrate, facilitate its curling, and evenly distribute force across the flat surface, making it less susceptible to ripples and wrinkles. Because the screen 23 is bonded to the rollable substrate, wrinkles and deformation are less likely to occur, thereby enhancing the display quality of the screen 23.

[0129] In some embodiments, the projection screen 2 further includes a flexible carrier; the screen piece 23 is adhered to the flexible carrier, a first side of the flexible carrier is fixedly connected to a curling assembly 221, and a second side of the flexible carrier opposite to the first side is fixedly connected to a lifting assembly 222. The curling assembly 221 can curl the flexible carrier, and the lifting assembly 222 can unfold the flexible carrier. When the flexible carrier is unfolded, the supporting screen piece 23 is in a flat state.

[0130] In this way, while the control mechanism 22 indirectly tightens the screen piece 23 through the flexible carrier, the flexible carrier bears a portion of the tensioning force of the control mechanism 22 , making the screen piece 23 less susceptible to damage, thereby ensuring the flatness of the screen piece 23 .

[0131] The flexible carrier can be a synthetic fabric, film, or other carrier that is easily curled and has sufficient load-bearing strength. When the flexible carrier is a synthetic fabric, the material of the flexible carrier is a synthetic material containing nylon. Nylon has high mechanical strength, good toughness, and high tensile and compressive strength. Therefore, when the control mechanism 22 tightens the flexible carrier, the flexible carrier is not easily deformed and has a smooth surface, thereby improving the flatness of the screen sheet 23.

[0132] The screen piece 23 and the flexible carrier are bonded together by double-sided tape or adhesive film, etc. Of course, they can also be bonded together by other means, which is not limited in the embodiment of the present application.

[0133] In some embodiments, the projection screen 2 includes a screen piece 23, a rollable substrate, and a flexible carrier. The screen piece 23 is bonded to the rollable substrate, and the side of the rollable substrate away from the screen piece 23 is bonded to the flexible carrier. A first side of the flexible carrier is fixedly connected to the rolling assembly 221, and a second side of the flexible carrier opposite to the first side is fixedly connected to the lifting assembly 222.

[0134] In some embodiments, when the control mechanism 22 includes a winding assembly 221, the winding assembly 221 includes a winding controller, a winding motor, and a reel. The winding controller is electrically connected to the winding motor, which is fixed to the base 21. The output shaft of the winding motor is fixedly connected to the end of the reel, and the first side of the screen 23 is fixedly connected to the reel. The winding controller can control the start and stop of the winding motor. When the winding motor is started, it can drive the reel to rotate. In this way, when the winding controller controls the reel to rotate, the screen 23 can be controlled to be wound around the reel.

[0135] In some embodiments, as Figure 14 As shown, the projection device also includes a storage portion 3 for accommodating the optical engine 1 and projection screen 2. The storage portion 3 has a light-transmitting area 31 and an opening 32. The light beam emitted by the optical engine 1 can pass through the light-transmitting area 31, and the control mechanism 22 can control the screen 23 to pass through the opening 32 and unfold. Thus, when the projection device is not in use, the optical engine 1 and projection screen 2 are stored in the storage portion 3, saving space. When the projection device is in use, the control mechanism 22 controls the screen 23 to unfold, and the optical engine 1 projects a light beam onto the screen 23, causing it to display an image.

[0136] The vertical distance from the center of the light-transmitting area 31 to the plane where the unfolded screen 23 lies is equal to the product of the throw ratio of the optical engine 1 and the width of the display area on the screen 23. The width of the display area refers to the horizontal dimension of the display area. This ensures that the light beam emitted by the optical engine 1 is accurately projected onto the display area of ​​the screen 23, ensuring clarity of the image displayed on the screen 23.

[0137] Because the throw ratio is a performance parameter of the optical engine 1 itself, its value depends on the selected optical engine 1. Specifically, different optical engines 1 result in different throw ratios, and consequently, different vertical distances from the center of the light-transmitting area 31 to the plane where the unfolded screen 23 lies. Therefore, during actual setup, the vertical distance from the center of the light-transmitting area 31 to the plane where the unfolded screen 23 lies is calculated based on the throw ratio of the optical engine 1 and the width of the display area. This ensures that the light beam emitted by the optical engine 1 is fully projected onto the display area of ​​the screen 23.

[0138] Optionally, the guide roller 24 is located within the storage portion 3. In this way, the guide roller 24 can be hidden within the storage portion 3, thereby enhancing the aesthetics of the projection screen 2 and pressing the screen 23 before it extends out of the storage portion 3. In other embodiments, the guide roller 24 is located above the storage portion 3 and is positioned so as not to interfere with the display of the projection image by the screen 23. Typically, the guide roller 24 is positioned near the storage portion 3 and below the lower edge of the projection image.

[0139] It should be noted that when the projection screen 2 includes a screen piece 23 and a flexible carrier, the size of the screen piece 23 is smaller than the size of the flexible carrier, and the edge of the screen piece 23 close to the storage portion 3 is spaced a certain distance from the storage portion 3. In this way, the guide roller 24 is located below the screen piece 23 and pressed against the flexible carrier, thereby avoiding obstruction of the projected image.

[0140] Next, the structure of the projection screen including the tensioning mechanism is explained in detail.

[0141] In some embodiments, the projection screen further includes a tensioning mechanism; the tensioning mechanism is fixedly connected to the curling assembly, and the curling assembly can control the tensioning mechanism to curl on the curling assembly; the second end of the lifting assembly is fixedly connected to the tensioning mechanism, and the lifting assembly can control the synchronous unfolding of the screen piece and the tensioning mechanism, and the tensioning mechanism can limit the pitch angle of the screen piece when unfolded; wherein the lifting assembly is located between the screen piece and the tensioning mechanism.

[0142] In this way, when the screen piece and the tensioning mechanism are in the extended state, since the lifting assembly is located between the screen piece and the tensioning mechanism, the pulling force of the tensioning mechanism on the lifting assembly is balanced with the pulling force of the screen piece on the lifting assembly. In this way, the tensioning mechanism can limit the pitch angle of the screen piece and correct the pitch angle of the screen piece at the same time.

[0143] In some embodiments, when the lifting assembly includes a crossbeam, the crossbeam is a thin plate-shaped crossbeam. The screen piece is fixedly connected to a first longitudinal side of the crossbeam, and the tensioning mechanism is connected to a second longitudinal side of the crossbeam. The screen piece and the tensioning mechanism are respectively located on opposite sides of the second support rod. In this way, the tensioning mechanism balances the tensioning force of the screen piece on the crossbeam by tensioning the crossbeam, thereby limiting the pitch angle of the screen piece.

[0144] In some embodiments, the curling assembly includes a first sub-curling assembly and a second sub-curling assembly; the first sub-curling assembly and the second sub-curling assembly are both connected to the base, the first sub-curling assembly and the curtain piece are located on the same side of the lifting assembly, and the second sub-curling assembly and the tensioning mechanism are located on the same side of the lifting assembly; the curtain piece is fixedly connected to the first sub-curling assembly, and the first sub-curling assembly can control the curtain piece to curl on the first sub-curling assembly; the tensioning mechanism is fixedly connected to the second sub-curling assembly, and the second sub-curling assembly can control the tensioning mechanism to curl on the second sub-curling assembly.

[0145] Thus, since the above embodiment describes the lifting assembly as being located between the screen piece and the tensioning mechanism, the first sub-rolling assembly and the screen piece are located on one side of the lifting assembly, while the second sub-rolling assembly and the tensioning mechanism are located on the other side of the lifting assembly. Furthermore, since the second sub-rolling assembly can control the tensioning mechanism to curl around the second sub-rolling assembly, after the screen piece tilts forward, the second sub-rolling assembly can be slightly adjusted in the positive direction to further curl the tensioning mechanism, thereby increasing the tensioning force of the tensioning mechanism on the second end of the lifting assembly to adjust the pitch angle of the screen piece. After the screen piece tilts backward, the second sub-rolling assembly can be slightly adjusted in the negative direction to slightly expand the tensioning mechanism, thereby reducing the tensioning force of the tensioning mechanism on the second end of the lifting assembly to adjust the pitch angle of the screen piece. Similarly, after the screen piece tilts forward or backward, the pitch angle of the screen piece can be adjusted by slightly adjusting the first sub-rolling assembly, or by simultaneously adjusting the first and second sub-rolling assemblies.

[0146] It should be noted that the first sub-curling assembly independently controls the curtain piece, and the second sub-curling assembly independently controls the tensioning mechanism, so that it is convenient to independently adjust the tensioning force of the curtain piece on the second end of the lifting assembly, and independently adjust the tensioning force of the tensioning mechanism on the second end of the lifting assembly.

[0147] In some embodiments, the tensioning mechanism includes an auxiliary roller and a tensioning assembly; the first end of the tensioning assembly is fixedly connected to the second end of the lifting assembly, the second end of the tensioning assembly is fixedly connected to the curling assembly, and both ends of the auxiliary roller are limited on the base and pressed on the tensioning assembly.

[0148] In this manner, because the first end of the tensioning assembly is fixedly connected to the second end of the lifting assembly, and the second end of the tensioning assembly is fixedly connected to the winding assembly, the winding assembly can be wound to retract the tensioning assembly, and the lifting assembly can be raised and lowered to deploy the tensioning assembly. The winding assembly can simultaneously control the screen sheet and the tensioning assembly to be wound around the winding assembly, thereby facilitating the synchronous winding and deployment of the screen sheet and the tensioning assembly. Furthermore, because the auxiliary roller is pressed against the tensioning assembly, it can control the tensioning force exerted by the tensioning assembly on the second end of the lifting assembly.

[0149] In some embodiments, the tensioning assembly is a first auxiliary cloth or a plurality of first tensioning ropes. In the case where the lifting assembly includes a thin plate-shaped crossbeam, if the tensioning assembly is the first auxiliary cloth, one side of the first auxiliary cloth is fixedly connected to a second side of the crossbeam along its length, and the other side of the first auxiliary cloth opposite the first side is fixedly connected to the coiling assembly. In this way, the first auxiliary cloth can tension the lifting assembly based on the crossbeam. If the tensioning assembly is a plurality of first tensioning ropes, each first tensioning rope is parallel to each other, and one end of each first tensioning rope can be fixedly connected to the second side of the crossbeam along its length, and the other end of each first tensioning rope is fixedly connected to the coiling assembly. In this way, the plurality of first tensioning ropes can tension the lifting assembly based on the crossbeam.

[0150] The first auxiliary cloth is fixedly connected to the crossbeam by screws or other means. Furthermore, the length of the side of the first auxiliary cloth fixedly connected to the crossbeam and the length of the side of the screen piece fixedly connected to the crossbeam are both less than or equal to the length of the crossbeam. Thus, under the condition that the forces on both sides of the lifting assembly are more balanced, the crossbeam can more comprehensively limit the position of the first auxiliary cloth and the screen piece.

[0151] When the tensioning assembly comprises multiple first tensioning ropes, the crossbeam may be provided with multiple fixing holes corresponding to the first tensioning ropes. Each tensioning rope may be tied to the crossbeam through a corresponding fixing hole. The spacing between each pair of first tensioning ropes is equal, so that each first tensioning rope exerts an equal tensioning force on the crossbeam, thereby ensuring the stability of the crossbeam and preventing deflection.

[0152] It should be noted that when the lifting assembly includes a crossbeam, when the curling assembly includes a first sub-curling assembly and a second sub-curling assembly, the tensioning mechanism is a second auxiliary cloth or multiple second tensioning ropes. When the lifting assembly includes a thin plate-shaped crossbeam, when the tensioning mechanism is a second auxiliary cloth, the connection method and connection position of the second auxiliary cloth to the crossbeam are the same or similar to the connection method and connection position of the first auxiliary cloth to the crossbeam, with the difference being that the second auxiliary cloth is fixedly connected to the second sub-curling assembly. When the tensioning mechanism is multiple second tensioning ropes, the connection method and connection position of the multiple second tensioning ropes to the crossbeam are the same or similar to the connection method and connection position of the multiple first tensioning ropes to the crossbeam, with the difference being that the multiple second tensioning ropes are fixedly connected to the second sub-curling assembly. This embodiment of the present application will not be further described.

[0153] In some embodiments, the auxiliary roller is strip-shaped, with its length parallel to the axis of the winding assembly. This allows the strip-shaped auxiliary roller to press against the tensioning assembly along its length, providing a wide range of positional control for the tensioning assembly. Furthermore, because the auxiliary roller's length is parallel to the axis of the winding assembly, the auxiliary roller ensures the smoothness of the tensioning assembly, preventing distortion of the tensioning assembly caused by the auxiliary roller, and thus preventing distortion of the lifting assembly.

[0154] The cross-section of the auxiliary roller is circular or polygonal. The auxiliary roller with a circular cross-section is easy to process and has a smooth surface, which is not likely to damage the screen piece.

[0155] It should be noted that when the auxiliary roller is pressed against the tensioning assembly, it may be stationary or capable of rotating about its longitudinal axis. If the auxiliary roller is capable of rotating, when the winding assembly is wound to retract the tensioning assembly or the lifting assembly is controlling the tensioning assembly to deploy, the auxiliary roller rotates, thereby reducing friction between the auxiliary roller and the tensioning assembly, thereby preventing damage to the tensioning assembly caused by friction between the auxiliary roller and the tensioning assembly. Of course, when the winding assembly is wound to retract the tensioning assembly or tightened to deploy the tensioning assembly, to prevent friction, the auxiliary roller is moved away from the tensioning assembly to avoid direct contact between the auxiliary roller and the tensioning assembly. After the tensioning assembly is deployed, the auxiliary roller is pressed against the tensioning assembly to limit the pitch angle of the screen piece.

[0156] In some embodiments, the auxiliary roller comprises a central shaft and a roller. The central shaft is connected to a base at both ends, and the roller is rotatably mounted on the central shaft. This allows the auxiliary roller to press against the tensioning assembly on the side closest to the screen sheet. Because the roller can rotate about the central shaft, relative motion occurs between the tensioning assembly and the roller when the winding assembly retracts or deploys the tensioning assembly. This significantly reduces friction between the roller and the tensioning assembly, thereby preventing wear on the tensioning assembly and improving flexibility in deploying and deploying the winding assembly.

[0157] In some embodiments, the auxiliary roller is provided with a lubricating coating. This coating prevents direct contact between the auxiliary roller and the tensioning assembly and provides lubrication between the two. This ensures smoother relative motion between the auxiliary roller and the tensioning assembly and prevents scratches on the tensioning assembly caused by the rough surface of the auxiliary roller, thereby extending the service life of the tensioning assembly. The lubricating coating can be a coating composed of flexible particles or a colloidal coating.

[0158] In some embodiments, the base is provided with two second guide grooves positioned opposite each other, with the ends of the auxiliary roller respectively positioned within the two second guide grooves and capable of moving within the second guide grooves under the action of an external force to adjust the pressure applied to the tensioning assembly. Thus, after the auxiliary roller contacts the tensioning assembly and continues to move along the length of the second guide grooves, it can push the tensioning assembly. Because the first end of the tensioning assembly is fixedly connected to the second end of the lifting assembly, the second end of the tensioning assembly is fixedly connected to the curling assembly, and both the lifting assembly and the curling assembly are in a stationary state, when the auxiliary roller pushes the tensioning assembly, it can increase the pressure applied to the tensioning assembly, thereby tightening the tensioning assembly. In this way, the tensioning force applied by the tensioning assembly to the second end of the lifting assembly is increased to a certain extent. Similarly, when the auxiliary roller moves away from the tensioning assembly along the length of the second guide grooves, the pressure applied by the auxiliary roller to the tensioning assembly decreases, and the tensioning force applied by the tensioning assembly to the second end of the lifting assembly decreases.

[0159] It should be noted that the projection screen also includes an auxiliary drive motor and an auxiliary transmission mechanism for controlling the movement of the auxiliary roller along the length direction of the second guide groove, wherein the auxiliary transmission mechanism has the same or similar structure as the transmission mechanism in the embodiment of the present application, and the embodiment of the present application will not elaborate on this.

[0160] Furthermore, the auxiliary roller can change the pitch angle of the screen piece based on the adjustment of the pressing force of the tensioning assembly. When the pitch angle of the screen piece is changed to the target pitch angle, the auxiliary roller is controlled to stop moving and fixed, thereby achieving the limitation of the pitch angle of the screen piece.

[0161] Since there are two second guide grooves, the base accordingly includes two support plates, and the two second guide grooves are respectively provided on the two support plates, so that the two ends of the auxiliary roller can pass through the two second guide grooves respectively.

[0162] The second guide groove may be in the shape of an elongated strip, an ellipse, or any other shape, as long as the auxiliary roller can be moved within and secured to the second guide groove. This embodiment of the present application is not limited thereto. The width of the second guide groove is slightly larger than the diameter or side length of the auxiliary roller's cross section. This allows the auxiliary roller to move more flexibly along the length of the second guide groove.

[0163] In some embodiments, the length of the second guide groove is horizontal or at an acute angle to the horizontal. For example, when the auxiliary roller moves within the second guide groove, it can move in the horizontal direction, thereby adjusting the contact position between the tensioning assembly and the auxiliary roller, and the relative horizontal position of the first end and the second end of the tensioning assembly, thereby adjusting the pressure applied by the auxiliary roller on the tensioning assembly.

[0164] In some embodiments, a lubricating member that fits tightly against the inner wall of each second guide groove is provided on the inner wall of the second guide groove. This can reduce the friction between the auxiliary roller and the second guide groove, enhance the smoothness of the movement of the auxiliary roller in the second guide groove, and facilitate improving the movement accuracy of the auxiliary roller.

[0165] Next, the structure of the projection screen including the adjustment screws is explained in detail.

[0166] In some embodiments, when the lifting assembly includes multiple groups of brackets, each group of brackets includes a first support rod and a second support rod, the first end of the first support rod and the base, the second end of the first support rod and the first end of the second support rod, and the second end of the second support rod and the screen are all rotatably connected, and the multiple groups of brackets can control the unfolding of the screen; an adjustment screw is provided on one of the first support rod and the second support rod, and one end of the adjustment screw abuts against the side wall of the other, and the adjustment screw is used to adjust the relative position of the second end of the first support rod and the first end of the second support rod to adjust the pitch angle of the screen.

[0167] In this way, when the screen is in the unfolded state, since one end of the adjustment screw provided on one of the first support rod and the second support rod abuts against the side wall of the other, the relative position of the second end of the first support rod and the first end of the second support rod can be adjusted by rotating the adjustment screw, thereby adjusting the inclination angle of the second support rod. Since the second end of the second support rod is connected to the screen, the pitch angle of the screen can be adjusted.

[0168] In some embodiments, the number of brackets is set to two, such that one bracket is respectively provided near the ends of the curling assembly, so that the two brackets can unfold the screen from the two ends near one side of the screen. Of course, the number of brackets can also be set to three, such that one bracket is respectively provided near the ends of the curling assembly, and one bracket is provided near the middle of the curling assembly. In this way, the three brackets can unfold the screen from the two ends of one side of the screen and the center of the side of the screen.

[0169] It should be noted that, in each set of brackets, assembly gaps are provided at the rotatable connections between the first end of the first support rod and the base, between the second end of the first support rod and the first end of the second support rod, and between the second end of the second support rod and the screen piece, so as to facilitate flexible extension and folding of the brackets.

[0170] In some embodiments, each bracket group includes a first connecting shaft, a first connecting slot is provided at the second end of the first support rod, the first end of the second support rod extends into the first connecting slot, and the second end of the first support rod and the first end of the second support rod are rotatably connected via the first connecting shaft. One end of an adjustment screw is screwed into the first connecting slot based on the outer wall of the first support rod and abuts the outer wall of the second support rod. In this way, the cooperation between the first connecting slot and the first end of the second support rod facilitates the adjustment screw disposed on the first support rod to abut the side wall of the second support rod.

[0171] The shape of the bottom surface of the first connecting groove is set according to the shape of the first support rod. For example, when the cross-section of the first support rod is square, the shape of the bottom surface of the first connecting groove is also square; when the cross-section of the first support rod is circular, the shape of the bottom surface of the first connecting groove is also circular.

[0172] A fixing nut is provided at each end of the first connecting shaft, and each fixing nut, when tightened, presses against the side wall of the first support rod. In this way, the first connecting shaft is fixedly connected to the first support rod, and when the second support rod rotates around the first connecting shaft, the angle between the second support rod and the first support rod changes, thereby enabling the bracket to be extended and folded.

[0173] In some embodiments, the first support rod includes a rod body and two first connecting plates; the first end of the rod body is rotatably connected to the base, the two first connecting plates are disposed at opposite ends of the second end of the rod body to form a first connecting slot, and at least one of the first connecting plates is provided with at least one adjustment screw. Thus, because the first end of the second support rod extends into the first connecting slot formed by the two first connecting plates, and at least one of the first connecting plates is provided with at least one adjustment screw, rotating the adjustment screw on the first connecting plate causes the adjustment screw to push the second support rod, thereby achieving adjustment of the relative position of the second support rod to the first support rod.

[0174] The two first connecting plates are arranged opposite to each other and are fixedly connected to the side walls of the rod body to form a first connecting groove with a larger space. The two first connecting plates are respectively welded to the rod body or respectively integrally formed with the rod body, which is not limited to the embodiment of the present application.

[0175] An adjustment screw is provided on any one of the two first connecting plates, and the adjustment screw is not located at the same height as the first connecting shaft. Thus, when the adjustment screw is rotated, the first connecting shaft is used as a fulcrum, the rotating screw abuts against the second support rod and pushes the second support rod, thereby adjusting the inclination angle of the second support rod and achieving adjustment of the relative position of the first end of the second support rod and the second end of the first support rod.

[0176] Of course, in some embodiments, two adjustment screws are provided on any one of the first connecting plates, and the line formed by the two adjustment screws is along the vertical direction or at an acute angle to the vertical direction. In actual use, the two adjustment screws are typically used in combination. Specifically, one of the adjustment screws located relatively above is fixed and kept in contact with the side wall of the second support rod, and the other adjustment screw is rotated so that it pushes the second support rod. In this way, the second support rod is controlled to swing in a direction perpendicular to the line connecting the two adjustment screws, thereby adjusting the inclination angle of the second support rod and adjusting the relative position of the first end of the second support rod and the second end of the first support rod.

[0177] Of course, in some embodiments, three adjustment screws are provided on any one of the first connecting plates, and the three adjustment screws are connected to form an equilateral triangle. In this way, the three adjustment screws can constrain the second support rod at three locations, and the ends of the three adjustment screws can form a plane, thereby effectively preventing the second support rod from randomly shaking toward the plane where the ends of the three adjustment screws lie, thereby making the movement state of the second support rod more stable.

[0178] It should be noted that one, two or three adjustment screws can be set on each first connecting plate. Since the first end of the second support rod extends into the first connecting groove formed by the two first connecting plates, the adjustment screws on the two first connecting plates push the second support rod in opposite directions, thereby realizing reciprocating adjustment of the inclination angle of the second support rod, and then realizing adjustment of the relative position of the first end of the second support rod and the second end of the first support rod.

[0179] In some embodiments, an adjustment screw is provided on one of the first support rod and the base, with one end of the adjustment screw abutting against a side wall of the other, and the adjustment screw is used to adjust the relative position of the first end of the first support rod and the base. In this way, the relative position of the first support rod and the base can be adjusted by rotating the adjustment screw.

[0180] In some embodiments, each bracket set further includes a second connecting shaft; the base is provided with a second connecting slot, into which the first end of the first support rod extends, and the first end of the first support rod and the base are rotatably connected via the second connecting shaft; one end of the adjustment screw can be screwed into the second connecting slot based on the outer wall of the base and abut against the outer wall of the first support rod. In this way, the cooperation between the second connecting slot and the first end of the first support rod facilitates the adjustment screw disposed in the second connecting slot of the base to abut against the side wall of the first support rod.

[0181] It should be noted that the structure of the second connecting groove is the same as or similar to that of the first connecting groove, and the setting method of the adjustment screw on the second connecting groove can be the same as or similar to the setting method of the adjustment screw on the first connecting groove, which will not be repeated in the embodiments of the present application.

[0182] In some embodiments, when the lifting assembly includes a crossbeam, an adjustment screw is provided on one of the second support rod and the crossbeam, with one end of the adjustment screw abutting against a sidewall of the other, and the adjustment screw is used to adjust the relative position of the second end of the second support rod and the crossbeam. Thus, the relative position of the second support rod and the crossbeam can be adjusted by rotating the adjustment screw.

[0183] In some embodiments, each bracket set further includes a third connecting shaft; a third connecting slot is provided on the crossbeam, into which the second end of the second support rod extends, and the second end of the second support rod and the crossbeam are rotatably connected via the third connecting shaft; one end of the adjustment screw is screwed into the third connecting slot based on the outer wall of the crossbeam and abuts against the outer wall of the second support rod. In this way, the cooperation between the third connecting slot and the second end of the second support rod facilitates the adjustment screw disposed in the third connecting slot of the crossbeam to abut against the side wall of the second support rod.

[0184] It should be noted that the structure of the third connecting groove is the same as or similar to that of the first connecting groove, and the setting method of the adjustment screw on the third connecting groove can be the same as or similar to the setting method of the adjustment screw on the first connecting groove, which will not be repeated in the embodiments of the present application.

[0185] In some embodiments, the projection screen further includes an adjustment washer positioned within the first connecting slot and slidably mounted on the first connecting shaft, with the adjustment washer being clamped between one end of the adjustment screw and the sidewall of the second support rod. Thus, the adjustment screw directly abuts the adjustment washer, thereby distributing the thrust applied by the end of the adjustment screw. This allows for a more even force distribution across the second support rod, while avoiding stress concentration and uneven force distribution caused by direct contact between the adjustment screw and the sidewall of the second support rod.

[0186] The adjustment washer may be a circular thin sheet structure, or a square, triangular or other shaped structure. It should be noted that when the first support rod includes a first connecting plate, in order to ensure that the adjustment screw provided at any position of the first connecting plate can abut against the adjustment washer, the shape of the adjustment washer can be set to be similar to that of the first connecting plate.

[0187] The thickness of the adjustment washer is much smaller than the width of the gap between the second end of the first support rod and the first end of the second support rod along the length direction of the first connecting axis, so that the adjustment screw can freely adjust the positional relationship between the first support rod and the second support rod. For example, the thickness of the adjustment washer is one-sixth of the width of the gap.

[0188] In some embodiments, each bracket set includes a second connecting shaft. When the base is provided with a second connecting slot, an adjustment washer is disposed within the second connecting slot. The adjustment washer is slidably mounted on the second connecting shaft and is clamped between one end of an adjustment screw threaded into the second connecting slot and a sidewall of the first support rod. The function and shape of the adjustment washer are the same as or similar to those of the adjustment washer in the above-described embodiments and are not further described in this embodiment.

[0189] In some embodiments, each bracket group includes a third connecting shaft. When a third connecting slot is provided on the crossbeam, an adjustment washer is also provided in the third connecting slot. The adjustment washer is slidably mounted on the third connecting shaft and is clamped between one end of an adjustment screw threaded into the third connecting slot and a sidewall of the second support rod. Similarly, the function and shape of the adjustment washer are the same as or similar to those of the adjustment washer in the above-described embodiments and are not further described in this embodiment.

[0190] In an embodiment of the present application, when the control mechanism propels the screen, the drive motor drives the transmission mechanism to automatically control the transmission mechanism, thereby facilitating the movement of the guide roller. Because the guide roller is movable within the first guide groove, after the guide roller contacts the screen and continues to move within the first guide groove, it pushes and presses the screen against it, thereby defining its pitch angle. This allows the guide roller to correct the position of the screen, thereby preventing distortion, blurring, and other issues in the image displayed on the screen, thereby improving the display quality of the projection screen. When the projection device is in use, the lifting assembly unfolds the screen from the reel assembly so that the screen receives the light beam emitted by the optical engine. When the projection device is not in use, the reel assembly controls the screen to reel back onto the reel assembly, thereby reducing the space occupied by the projection screen.

[0191] The above description is merely an illustrative embodiment of the embodiments of the present application and is not intended to limit the embodiments of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the embodiments of the present application.

Claims

1. A projection device, characterized in that: The projection device comprises: An optical engine, the optical engine is used to emit a light beam, and the optical engine includes a light source, an optical-mechanical system, and a lens; A projection screen comprising a base, a control mechanism, a screen, a guide roller, a transmission mechanism and a drive motor; The control mechanism is fixed on the base, and the control mechanism is used to support the screen, and the screen is used to receive the light beam when supported; The base has two first guide grooves positioned opposite to each other, and the two ends of the guide roller are respectively located in the two first guide grooves. The transmission mechanism is rotatably limited on the base. The drive motor is fixed to the base, and the output shaft of the drive motor is connected to the transmission mechanism. The transmission mechanism is also connected to the guide roller. The drive motor can drive the guide roller to move in the first guide groove through the transmission mechanism to press against the screen piece and limit the pitch angle of the screen piece.

2. The projection device according to claim 1, wherein: The transmission mechanism includes a worm and a worm wheel; The length direction of the worm is parallel to the length direction of the first guide groove, and the worm is rotatably limited on the base. The worm is connected to the output shaft of the drive motor, and the drive motor can drive the worm to rotate along its own circumferential direction; The worm wheel is axially limited at the first end of the guide roller, and the worm is engaged with the worm wheel.

3. The projection device according to claim 2, wherein: The axial direction of the output shaft of the driving motor is collinear with the length direction of the worm, and the output shaft of the driving motor is fixedly connected to the end of the worm.

4. The projection device according to claim 2, wherein: The transmission mechanism further includes a first gear and a second gear, wherein the first gear is fixedly connected to the output shaft of the drive motor along the axial direction, and the second gear is fixedly connected to one end of the worm along the axial direction, and the first gear is meshed with the second gear.

5. The projection device according to claim 4, wherein: The axial direction of the output shaft of the driving motor is parallel to the length direction of the worm, and the first gear and the second gear are both cylindrical gears.

6. The projection device according to claim 4, wherein: The axial direction of the output shaft of the driving motor is perpendicular to the length direction of the worm, and the first gear and the second gear are both bevel gears.

7. The projection device according to claim 1, wherein: The transmission mechanism includes a lead screw; The length direction of the lead screw is parallel to the length direction of the first guide groove, and the lead screw is rotatably limited on the base, and the lead screw is threadedly connected to the first end of the guide roller; The output shaft of the driving motor is connected to the lead screw, and the driving motor can drive the lead screw to rotate.

8. The projection device according to claim 2 or 7, wherein: The transmission mechanism also includes a third gear and a rack. The third gear is axially limited at the second end of the guide roller. The rack is fixed on the base. The length direction of the rack is parallel to the length direction of the first guide groove and is engaged with the third gear.

9. The projection device according to claim 1, wherein: The length direction of the first guide groove is horizontal.

10. The projection device according to claim 1, wherein: The control mechanism includes a curling assembly and a lifting assembly; The curling assembly is limited on the base, the first side of the curtain piece is fixedly connected to the curling assembly, and the curling assembly can rotate along its own circumferential direction to control the curtain piece to be retracted; The first end of the lifting assembly is fixedly connected to the base, and the second end of the lifting assembly is fixedly connected to a second side of the curtain piece opposite to the first side. The lifting assembly can control the unfolding of the curtain piece.

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