Projector based on holographic projection technology

Abstract

The invention relates to the technical field of holographic projection, and discloses a projector based on a holographic projection technology, and the projector comprises a box body. A four-side projection screen is mounted above the box body through a rotating shaft; the four projection screens can rotate around the rotating shaft to abut against each other and be spliced into an inverted pyramid structure, or are parallel to the upper surface of the box body. A mounting frame sleeves the upper part of the outer surface of the box body and can move up and down relative to the box body; the four sides, facing the box body, of the installation frame are each of an open structure, and four installation cavities communicating in sequence are formed. An unwinding shaft and a rope winding shaft are arranged in the two opposite mounting cavities respectively, a protective film is fixed to one end of the unwinding shaft, the other end of the protective film is fixedly connected with an exhaust shaft, and the exhaust shaft is connected with the rope winding shaft through a pull rope; the protection film can cover the four projection screens parallel to the upper surface of the box body. The operation that the projection screen is protected by a special protection device after being detached is avoided, the convenience in the using process is effectively improved, and transportation and storage are further facilitated.

Description

Technical Field

[0001] This invention relates to the field of holographic projection technology, specifically to a projector based on holographic projection technology. Background Technology

[0002] A pyramid-shaped holographic projector mainly consists of a mounting platform, a projection source, and a pyramid-shaped projection screen. Before and after use, the pyramid-shaped projection screen needs to be disassembled and reassembled on the mounting platform, and requires protection using a special protective device. This design makes the pyramid-shaped holographic projector inconvenient to disassemble and reassemble in practical use, and also inconvenient to store and transport. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a projector based on holographic projection technology, which can effectively solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a projector based on holographic projection technology, comprising a housing, with four projection screens disposed on the top of the housing; each of the four projection screens is connected to the housing via a pivot, and the four projection screens can rotate around the pivot until they abut against each other and are spliced ​​into an inverted pyramid structure, or parallel to the upper surface of the housing; a mounting frame is fitted onto the upper part of the outer surface of the housing, and the mounting frame can move up and down relative to the housing; the four sides of the mounting frame facing the housing are open structures, forming four sequentially connected mounting cavities; an unwinding shaft and a winding shaft are respectively disposed in two opposite mounting cavities, and both ends of the unwinding shaft and the winding shaft are rotatably connected to the mounting frame; a protective film is fixed to one end of the unwinding shaft, and an exhaust shaft is fixedly connected to the other end of the protective film, and the exhaust shaft is connected to the winding shaft via a pull rope; the rotation of the unwinding shaft and the rotation of the winding shaft can be used to wind and unwind the protective film; the protective film can cover the four projection screens parallel to the upper surface of the housing; The protective film is hollow and has an air bladder connected to one side; both the protective film and the air bladder can be inflated and deflated; the inflated rear air bladder can surround the projection screen parallel to the upper surface of the box and form a seal with the upper part of the box.

[0005] Preferably, the unwinding shaft is provided with a first chamber, a second chamber, a third chamber and a fourth chamber in sequence along the axial direction, with the first chamber and the fourth chamber passing through both ends of the unwinding shaft respectively; an air inlet pipe is provided in the fourth chamber, with the other end of the air inlet pipe passing through and being fixedly connected to the mounting frame; the end face of the air inlet pipe located in the fourth chamber is arranged at an angle; the inner cavity of the protective film is connected to the second chamber.

[0006] Preferably, a piston is slidably installed in the third chamber; one-way valves are installed between the second and third chambers and between the third and fourth chambers; the piston is also equipped with a one-way valve; a piston rod is fixedly connected to one end of the piston, and the other end of the piston rod extends into the fourth chamber and abuts against the inclined surface on the intake pipe; a spring abuts against the other end of the piston.

[0007] Preferably, both ends of the exhaust shaft are open to form two exhaust chambers, and an intake chamber is provided between the two intake chambers; a rotating sleeve is provided inside the exhaust chamber, the rotating sleeve is rotatably connected to the exhaust shaft, and an exhaust hole is provided inside the rotating sleeve, and the intake chamber is intermittently connected to the exhaust chamber through the air hole; the inner cavity of the protective film is connected to the intake chamber.

[0008] Preferably, a push rod is screwed to one end of the rotating sleeve away from the intake chamber, and a slider is fixedly connected to the other end of the push rod; the slider is axially slidably connected to the exhaust shaft and can drive the rotating sleeve to reciprocate.

[0009] Preferably, a first magnetic block is embedded in the slider, and a second magnetic block and a third magnetic block are disposed in the mounting frame between the unwinding shaft and the winding shaft; the second magnetic block is close to the unwinding shaft and is attracted to the first magnetic block; the third magnetic block is close to the exhaust assembly and is repelled by the first magnetic block.

[0010] Preferably, the axial reciprocating movement of the slider is achieved by alternating cooperation between magnetic block one and magnetic block two and magnetic block three. When magnetic block one and magnetic block two are in cooperation, the air intake chamber and the exhaust chamber are separated from each other. When magnetic block one and magnetic block three are in cooperation, the air intake chamber and the exhaust chamber are connected to each other.

[0011] Compared with the prior art, the present invention provides a projector based on holographic projection technology, which has the following beneficial effects: 1. This invention uses four independent projection screens hinged to the housing, so that when projection is in use, the four projection screens can form an inverted pyramid structure together and cooperate with four projection sources. When not in use, all four projection screens can be rotated to be parallel to the upper surface of the housing and respectively abut against the upper surface of the four pads, which greatly reduces the height of the entire projector, thereby facilitating the storage and transportation of the entire projector.

[0012] 2. By using a rotatable unwinding shaft and a winding rope, the protective film can be unwound and rewound. When the projector is not in use, the protective film can cover all four projection screens. An inflation device is installed inside the unwinding shaft, creating a hollow structure for the protective film. Airbags are connected to the protective film, with the length and width of the airbags being smaller than the length and width of the upper surface of the housing, but larger than the length and width of the rectangle containing the four pads. This allows the protective film and airbags to be inflated as the unwinding shaft rotates. The inflated airbags surround all four projection screens and form a seal with the upper surface of the housing, thus providing complete protection for all four projection screens. This eliminates the need to disassemble and apply a dedicated protective device, significantly improving convenience during use and further facilitating transportation and storage. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention when used for holographic projection; Figure 2 This is a schematic diagram of the structure when the invention is decommissioned; Figure 3 This is a schematic diagram of the internal structure of the present invention. Figure 1 ; Figure 4 This is a schematic diagram of the internal structure of the present invention. Figure 2 ; Figure 5 This is a schematic diagram of the structure of the second transposition component of the present invention; Figure 6 This is a schematic diagram of the mounting frame of the present invention; Figure 7 This is a schematic diagram of the structure of the unwinding assembly of the present invention; Figure 8 This is a schematic diagram of the exhaust assembly of the present invention.

[0014] The components include: 1. Housing; 101. Pad strip; 102. Bayonet; 2. Projection source; 21. First transposition assembly; 211. Transposition shaft; 212. Shaft seat; 213. First clamping plate; 214. Second clamping plate; 215. Motor; 3. Projection screen; 31. Second transposition assembly; 311. Lifting block; 312. Fixing block; 313. Support; 314. Clamping block; 315. Tension spring; 316. Pull rod; 317. Guide groove; 318. Electric push rod. 4. Enclosure frame; 5. Mounting frame; 51. Guide groove; 6. Protective film; 61. Airbag; 7. Unwinding assembly; 71. Unwinding shaft; 711. First chamber; 712. Second chamber; 713. Third chamber; 714. Fourth chamber; 72. Inlet pipe; 73. Piston; 74. One-way valve; 75. Spring; 76. Plug rod; 77. Motor three; 8. Exhaust assembly; 81. Exhaust shaft; 811. Inlet chamber; 812. Exhaust chamber; 82. Rotating sleeve; 83. Push rod; 84. Slider; 85. Magnetic block one; 9. Rope winding shaft; 10. Pull rope; 11. Motor two; 12. Electric push rod two. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Please see Figures 1 to 8 The present invention discloses a projector based on holographic projection technology, comprising a housing 1, four projection sources 2, and four projection screens 3; wherein, the four projection sources 2 are detachably mounted on the upper end of the housing 1 and arranged in a circular array; the four projection screens 3 are all located above the housing 1 between the four projection sources 2 and are all connected to the housing 1 via a rotating shaft; the four projection sources 2 are respectively engaged with the four projection screens 3.

[0017] Four pads 101 are fixedly connected to the upper end of the housing 1; by rotating around the pivot, the four projection screens 3 can switch between the first state and the second state; in the first state, the four projection screens 3 are spliced ​​together to form an inverted pyramid structure; in the second state, the four projection screens 3 are arranged in parallel above the housing 1 and respectively abut against the upper surface of the four pads 101.

[0018] A frame 4 is fixedly fitted on the upper part of the outer surface of the housing 1, and an installation frame 5 is installed between the frame 4 and the housing 1. The installation frame 5 is arranged around the housing 1, and the four sides facing the housing 1 are open structures, forming four sequentially connected installation cavities. Guide grooves 51 are respectively opened on the vertical walls of the two opposite installation cavities. The two ends of the guide grooves 51 extend first along the length of the installation cavity, and then extend downward at an angle. The length of the guide grooves 51 is greater than the length of the housing 1.

[0019] An unwinding assembly 7 is installed in an installation cavity located between two guide grooves 51, and a protective film 6 is wound on the unwinding assembly 7. The unwinding and rewinding of the protective film 6 are achieved through the winding and unwinding actions of the unwinding assembly 7.

[0020] The protective film 6 is connected to an exhaust assembly 8 at the end away from the unwinding assembly 7, and the two ends of the exhaust assembly 8 extend into two guide grooves 51 respectively.

[0021] A winding shaft 9 and a second motor 11 are located in another mounting cavity between the two guide grooves 51. Both ends of the winding shaft 9 are rotatably connected to the mounting frame 5. A pull rope 10 is wound around the winding shaft 9, and the end of the pull rope 10 away from the winding shaft 9 is connected to the exhaust assembly 8. The second motor 11 is fixedly connected to the mounting frame 5, and the output end of the second motor 11 is driven by the winding shaft 9 through a gear transmission mechanism. The rotation of the output end of the second motor 11 realizes the rotation of the winding shaft 9, thereby realizing the winding and unwinding of the pull rope 10 on the winding shaft 9.

[0022] An electric push rod 12 is fixedly connected to the lower end of the frame 4, and the output end of the electric push rod 12 is fixedly connected to the mounting frame 5. The up-and-down reciprocating motion of the mounting frame 5 is achieved by the extension and retraction of the output end of the electric push rod 12.

[0023] The upper surface of the frame 4 is flush with the upper surface of the housing 1. The upper surface of the mounting frame 5 can be lowered to be flush with the upper surface of the housing 1.

[0024] like Figure 1 As shown, the present invention provides a projector based on holographic projection technology. When using holographic projection, the upper surface of the housing 1, the upper surface of the frame 4, and the upper surface of the mounting frame 5 are on the same plane. The four projection screens 3 together form an inverted pyramid structure, and the four projection sources 2 point to the four projection screens 3 respectively.

[0025] It should be noted that the projection screen 3 is made of acrylic sheet.

[0026] like Figure 2 and Figure 3 As shown, the present invention discloses a projector based on holographic projection technology. When not in use, the upper surface of the mounting frame 5 moves up to the top of the housing 1 under the drive of the electric push rod 12. The four projection screens 3 are arranged parallel to each other above the housing 1 and respectively abut against the upper surfaces of the four pads 101. The protective film 6 is in an unrolled state and covers the top of the four projection screens 3, protecting the projection screens 3.

[0027] As a further explanation of the above technical solution, the upper end of the housing 1 is provided with four bayonet slots 102. Inside the housing 1, below each of the four bayonet slots 102, a first transposition component 21 is installed. The four first transposition components 21 are used to install four projection sources 2 respectively. Through the transposition action of the first transposition components 21, the transmitting end of the projection source 2 can move back and forth between the top of the housing 1 and inside the housing 1 through the bayonet slots 102. With the first transposition components 21, the projector can be completely retracted into the housing 1 when not in use, thus achieving protection.

[0028] like Figure 4 As shown, the first transposition assembly 21 includes a transposition shaft 211, a bearing seat 212, and a motor 215. The bearing seat 212 is fixed to the inner bottom surface of the housing 1. The transposition shaft 211 passes horizontally through and is rotatably connected to the bearing seat 212. The motor 215 is fixedly installed on the bearing seat 212 and is connected to the transposition shaft 211 in a transmission manner. The motor 215 drives the transposition shaft 211 to reciprocate on the bearing seat 212.

[0029] The first transposition component 21 also includes a first card plate 213 and a second card plate 214; both the first card plate 213 and the second card plate 214 are fixedly installed on the outer circumferential surface of the transposition shaft 211, and can be alternately inserted into the slot 102 by the reciprocating swing of the transposition shaft 211. The projection source 2 is embedded in the second card plate 214.

[0030] As a further explanation of the above technical solution, such as Figure 3 , Figure 4 and Figure 5 As shown, a second switching component 31 is installed inside the housing 1. The second switching component 31 is used to switch the four projection screens 3 between the first state and the second state.

[0031] The second switching component 31 includes a lifting block 311 and an electric push rod 318. The electric push rod 318 is vertically fixed to the inner bottom surface of the housing 1. The output end of the electric push rod 318 faces upward and is fixedly connected to the lifting block 311. Four supports 313 are fixedly installed in a circular array on the upper end of the lifting block 311. Each of the four supports 313 has a clamping block 314 hinged to its upper end. The upper ends of the four clamping blocks 314 extend to the top of the housing 1 and are fixedly connected to the four projection screens 3 respectively. Above the lifting block 311, there are four fixing blocks 312 located between the four supports 313. One side of the upper end of each of the four fixing blocks 312 is fixed to the inner top surface of the box 1. The other side of the upper end of each of the four fixing blocks 312 is inclined downward and each has a guide groove 317 arranged along the inclined direction. Each of the four guide slots 317 contains a pull rod 316, which is fixedly connected to the four clamping blocks 314. Each of the four pull rods 316 is equipped with a tension spring 315, which is connected to the four fixing blocks 312. All four tension springs 315 are in a pre-tensioned state.

[0032] When the four-sided projection screen 3 is in the first state, the lifting block 311 is in the highest position, and the four tension springs 315 pull the four pull rods 316 to the top of the four guide slots 317; under the action of the rebound force of the four tension springs 315, the four-sided projection screen 3 remains in the first state.

[0033] When the four-sided projection screen 3 is switched from the first state to the second state, the output end of the electric push rod 318 retracts, moves the lifting block 311 and the support 313 downward, moves the clamping block 314 downward, and swings under the cooperation of the pull rod 316 and the guide groove 317, further stretching the tension spring 315, so that the projection screen 3 swings until it is parallel to the upper surface of the housing 1.

[0034] When switching the four-sided projection screen 3 from the second state to the first state, the output end of the electric push rod 318 extends, causing the lifting block 311 and the support 313 to move upward, causing the clamping block 314 to move upward, the tension spring 315 to rebound, and the pull rod 316 to move along the guide groove 317 to the top of the guide groove 317, thereby causing the clamping block 314 to swing, causing the projection screen 3 to swing, until the four-sided projection screen 3 is in the first state.

[0035] It should be noted that the upper end of the box 1 has four openings, and four clamping blocks 314 extend to the top of the box 1 through the four openings.

[0036] As a further explanation of the above technical solution, such as Figure 3 , Figure 6 , Figure 7 and Figure 8 As shown, the unwinding assembly 7 includes an unwinding shaft 71, an air inlet pipe 72, and a motor 77; Both ends of the unwinding shaft 71 are rotatably connected to the mounting frame 5. The unwinding shaft 71 is provided with a first chamber 711, a second chamber 712, a third chamber 713 and a fourth chamber 714 in sequence along the axial direction. The first chamber 711 and the fourth chamber 714 pass through both ends of the unwinding shaft 71 respectively. One end of the air intake pipe 72 extends into the fourth chamber 714, and the other end passes through the mounting frame 5 and is fixedly connected to the mounting frame 5; the end face of the air intake pipe 72 located in the fourth chamber 714 is arranged at an angle; the output shaft of the motor 3 77 is located in the first chamber 711 and is connected to the unwinding shaft 71; the housing of the motor 3 77 is exposed in the first chamber 711 and is fixedly connected to the mounting frame 5. One-way valves 74 are installed between the second chamber 712 and the third chamber 713, and between the third chamber 713 and the fourth chamber 714. A piston 73 is slidably installed in the third chamber 713. One end of the piston 73 is fixedly connected to a stopper rod 76, and the other end of the stopper rod 76 extends into the fourth chamber 714 and abuts against the inclined surface on the intake pipe 72. The other end of the piston 73 abuts against a spring 75, which is in a pre-compressed state. A one-way valve 74 is also installed on the piston 73.

[0037] The protective film 6 is hollow and has an airbag 61 connected to one side; one end of the protective film 6 is fixed to one end of the unwinding shaft 71, and the inner cavity of the protective film 6 is connected to the second chamber 712. The length and width of the airbag 61 are smaller than the length and width of the upper surface of the housing 1, respectively, and larger than the length and width of the rectangle containing the four pads 101, so as to be able to surround the four projection screens 3 parallel to the upper surface of the housing 1.

[0038] like Figure 3 and Figure 6 As shown, when the projector is not in use, the airbag 61 abuts against the upper surface of the housing 1 and is located on the outside of the four pads 101, forming a protective enclosure for the projection screen 3 together with the housing 1 and the protective film 6.

[0039] The exhaust assembly 8 includes an exhaust shaft 81, which is fixed to the pull rope 10 and has its two ends located in two guide grooves 51 respectively. Both ends of the exhaust shaft 81 are open to form two exhaust chambers 812, and an intake chamber 811 is provided between the two intake chambers 811.

[0040] Inside the exhaust chamber 812, a rotating sleeve 82, a push rod 83, and a slider 84 are arranged sequentially from near to far from the intake chamber 811. The rotating sleeve 82 is rotatably connected to the exhaust shaft 81. An exhaust hole is provided inside the rotating sleeve 82. The exhaust hole intermittently connects the intake chamber 811 and the exhaust chamber 812 through the reciprocating rotation of the rotating sleeve 82. One end of the push rod 83 is screwed into the rotating sleeve 82, and the other end is fixedly connected to the slider 84. The slider 84 is axially slidably connected to the exhaust shaft 81. By sliding the slider 84 axially back and forth, the push rod 83 is pushed to move back and forth, thereby realizing the reciprocating swing of the rotating sleeve 82, and thus realizing the intermittent connection between the exhaust port and the intake chamber 811 and the exhaust chamber 812.

[0041] The other end of the protective film 6 is fixed to the exhaust shaft 81, and its inner cavity is connected to the intake cavity 811.

[0042] A magnetic block 85 is embedded in the slider 84. Magnetic blocks 2 and 3 are respectively embedded at both ends of the guide groove 51 in the mounting frame 5. Magnetic block 2 is close to the unwinding assembly 7 and is attracted to magnetic block 85, while magnetic block 3 is close to the exhaust assembly 8 and is repelled by magnetic block 85. The slider 84 moves axially back and forth by alternating cooperation between magnetic block 85 and magnetic blocks 2 and 3. When magnetic block 85 cooperates with magnetic block 2, the air intake chamber 811 and the exhaust chamber 812 are separated from each other. When magnetic block 85 cooperates with magnetic block 3, the air intake chamber 811 and the exhaust chamber 812 are connected.

[0043] As a further explanation of the above technical solution, the unwinding assembly 7, the venting assembly 8, and the second and third magnetic blocks are used in the following manner: exist Figure 1As shown, the protective film 6 is wound onto the unwinding shaft 71, the pull rope 10 unwinds, the exhaust assembly 8 is on the same side as the unwinding assembly 7, and the magnetic block 1 85 and the magnetic block 2 are attracted to each other, and the air inlet chamber 811 and the exhaust chamber 812 are separated from each other.

[0044] from Figure 1 Switch to as shown Figure 2 In the indicated state, the projection source 2 is first fully retracted into the housing 1 by the first switching component 21, so that the first card plate 213 closes the slot 102. The four projection screens 3 are placed in a horizontal state by the second switching component 31. Then, the third motor 77 and the second motor 11 are started to drive the unwinding shaft 71 to rotate, unwinding the protective film 6. The winding shaft 9 is driven to rotate, winding the pull rope 10, so that the exhaust component 8 moves along the guide groove 51 to the side of the winding shaft 9, pulling the protective film 6 and making the protective film 6 cover the top of the four projection screens 3. After the airbag 61 surrounds the four pads 101, the third motor 77 and the second motor 11 are both stopped. At this time, the magnetic block 3 is located between the magnetic block 85 and the winding shaft 9, and the air inlet chamber 811 and the exhaust chamber 812 remain separated from each other.

[0045] During the unwinding of the protective film 6 and the process of surrounding the four pads 101 with the airbag 61, the stopper rod 76 rotates with the unwinding shaft 71 and cooperates with the inclined surface on the air inlet pipe 72, causing the spring 75 to reciprocate and return to its original position. This causes the piston 73 to move within the third chamber 713, drawing in air from outside the housing 1 through the air inlet pipe 72 into the fourth chamber 714. Then, the air enters the third chamber 713 and the second chamber 712 sequentially through the one-way valves 74, and finally enters the protective film 6 and the airbag 61 to inflate them. This creates a seal between the inflated rear airbag 61 and the upper end of the housing 1, thereby achieving effective protection for the four projection screens 3.

[0046] Before winding up the protective film 6, the protective film 6 is further unwound by motor 3 77 and motor 2 11, so that magnetic block 1 85 moves to cooperate with magnetic block 3, pushes slider 84 to slide, and makes rotating sleeve 82 rotate, realizing the connection between air inlet chamber 811 and air outlet chamber 812. Then, the protective film 6 is wound up by motor 3 77 and motor 2 11, and the air in the protective film 6 and air bag 61 is discharged through air inlet chamber 811 and air outlet chamber 812, thus performing the air exhaust operation of protective film 6 and air bag 61.

[0047] It should be noted that during the winding process of the protective film 6, the piston 73 continues to move, inflating the protective film 6 and the air bladder 61. However, since the cavity in the protective film 6 is strip-shaped, connecting the second chamber 712 and the air inlet chamber 811, and the cavity is not completely blocked during the winding process, the inflated gas can also be discharged through the air inlet chamber 811 and the exhaust chamber 812 during the winding process.

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A projector based on holographic projection technology comprising a box (1), characterized in that: The upper part of the box (1) is provided with four projection screens (3); the four projection screens (3) are connected with the box (1) through rotating shafts, and the four projection screens (3) can be rotated around the rotating shafts to abut against each other and be spliced into an inverted pyramid structure, or be parallel to the upper surface of the box (1); the upper part of the outer surface of the box (1) is sleeved with a mounting frame (5), the mounting frame (5) can move up and down relative to the box (1); the four sides of the mounting frame (5) facing the box (1) are all open structures, and four mounting cavities in sequence are formed; two opposite mounting cavities are respectively provided with a pay-off shaft (71) and a rope winding shaft (9), the two ends of the pay-off shaft (71) and the two ends of the rope winding shaft (9) are all rotationally connected with the mounting frame (5); one end of the pay-off shaft (71) is fixedly provided with a protective film (6), the other end of the protective film (6) is fixedly connected with an exhaust shaft (81), and the exhaust shaft (81) is connected with the rope winding shaft (9) through a pull rope (10); the pay-off and pay-in of the protective film (6) can be realized through the rotation of the pay-off shaft (71) and the rotation of the rope winding shaft (9); the protective film (6) can cover the four projection screens (3) parallel to the upper surface of the box (1); The protective film (6) is hollow, and one side is communicated with an air bag (61); the protective film (6) and the air bag (61) can be inflated and deflated; the inflated air bag (61) can surround the four projection screens (3) parallel to the upper surface of the box (1), and a seal can be formed between the air bag (61) and the upper end of the box (1).

2. A projector based on holographic projection technology according to claim 1, characterized in that: The pay-off shaft (71) is sequentially provided with a first chamber (711), a second chamber (712), a third chamber (713) and a fourth chamber (714) in the axial direction, and the first chamber (711) and the fourth chamber (714) penetrate through the two ends of the pay-off shaft (71); the fourth chamber (714) is provided with an air inlet pipe (72), one end of the air inlet pipe (72) penetrates through and is fixedly connected with the mounting frame (5); the end face of the air inlet pipe (72) located in the fourth chamber (714) is arranged in a slope; the inner cavity of the protective film (6) is communicated with the second chamber (712).

3. A projector based on holographic projection technology according to claim 2, characterized in that: The third chamber (713) is slidably provided with a piston (73); the second chamber (712) and the third chamber (713), and the third chamber (713) and the fourth chamber (714) are all provided with one-way valves (74); the piston (73) is also provided with a one-way valve (74); one end of the piston (73) is fixedly connected with a plug rod (76), the other end of the plug rod (76) extends into the fourth chamber (714) and abuts against the slope on the air inlet pipe (72); the other end of the piston (73) abuts against a spring (75).

4. A projector based on holographic projection technology according to claim 3, characterized in that: Both ends of the exhaust shaft (81) are open, forming two exhaust chambers (812), and an intake chamber (811) is provided between the two intake chambers (811); a rotating sleeve (82) is provided inside the exhaust chamber (812), the rotating sleeve (82) is rotatably connected to the exhaust shaft (81), an exhaust hole is provided inside the rotating sleeve (82), and the intake chamber (811) is intermittently connected to the exhaust chamber (812) through the air hole; the inner cavity of the protective film (6) is connected to the intake chamber (811).

5. A projector based on holographic projection technology according to claim 4, characterized in that: The rotating sleeve (82) is screwed with a push rod (83) at one end away from the air intake chamber (811), and a slider (84) is fixedly connected to the other end of the push rod (83); the slider (84) is axially slidably connected to the exhaust shaft (81) and can drive the rotating sleeve (82) to reciprocate.

6. A projector based on holographic projection technology according to claim 5, characterized in that: The slider (84) is embedded with a magnetic block 1 (85). The mounting frame (5) is provided with a magnetic block 2 and a magnetic block 3 located between the unwinding shaft (71) and the winding shaft (9). The magnetic block 2 is close to the unwinding shaft (71) and is attracted to the magnetic block 1 (85). The magnetic block 3 is close to the exhaust assembly (8) and is repelled by the magnetic block 1 (85).

7. A projector based on holographic projection technology according to claim 6, characterized in that: By alternating between magnetic block one (85) and magnetic block two and magnetic block three, the slider (84) can move axially back and forth. When magnetic block one (85) and magnetic block two are engaged, the intake chamber (811) and the exhaust chamber (812) are separated from each other. When magnetic block one (85) and magnetic block three are engaged, the intake chamber (811) and the exhaust chamber (812) are connected to each other.

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