阅读说明：本技术 投影屏幕 (Projection screen ) 是由 逄相来 杨长明 张重扬 董淑斌 于 2020-04-15 设计创作，主要内容包括：本申请公开了一种投影屏幕,属于投影技术领域。该投影屏幕包括：固定框架、幕布和边框,幕布的边缘包裹固定框架,且拉紧固定在固定框架上；边框包括至少两根子边框,每根子边框的第一端部设置有第一插接结构和第二插接结构,每根子边框的第二端部设置有第三插接结构和第四插接结构。本申请实施例中,第一子边框的第一插接结构和第二插接结构与第二子边框的第三插接结构和第四插接结构在长边方向、宽边方向和厚度方向上的抵接固定,保证了边框的稳固性,避免了在外力作用下可能发生的扭曲变形,进而避免了幕布发生扭曲变形的可能,提高了幕布的画面显示效果,也即是提高了投影屏幕的画面显示效果。(The application discloses projection screen belongs to projection technical field. The projection screen includes: the curtain comprises a fixed frame, a curtain and a frame, wherein the edge of the curtain wraps the fixed frame and is fastened and fixed on the fixed frame; the frame includes two piece at least sub-frames, and the first end of every sub-frame is provided with first grafting structure and second grafting structure, and the second end of every sub-frame is provided with third grafting structure and fourth grafting structure. In the embodiment of the application, the first inserting structure and the second inserting structure of the first sub-frame and the third inserting structure and the fourth inserting structure of the second sub-frame are fixed in the butt joint in the long edge direction, the wide edge direction and the thickness direction, the stability of the frame is ensured, the distortion which possibly occurs under the action of external force is avoided, the possibility of distortion of the curtain is further avoided, the picture display effect of the curtain is improved, and the picture display effect of the projection screen is also improved.)

1. A projection screen, comprising:

a fixed frame;

the edge of the curtain wraps the fixed frame and is tensioned and fixed on the fixed frame, and the curtain is used for receiving the light beams emitted by the optical engine to display pictures;

the frame comprises at least two sub-frames, a first end part of each sub-frame is provided with a first splicing structure and a second splicing structure, a second end part of each sub-frame is provided with a third splicing structure and a fourth splicing structure, and the at least two sub-frames are spliced in sequence from head to tail based on the first splicing structure, the second splicing structure, the third splicing structure and the fourth splicing structure;

the first inserting structure of the first sub-frame and the third inserting structure of the second sub-frame are in butt joint fixation in the long side direction and the wide side direction of the curtain, the second inserting structure of the first sub-frame and the fourth inserting structure of the second sub-frame are in butt joint fixation in the thickness direction of the curtain, and the first sub-frame and the second sub-frame refer to any two sub-frames to be inserted in the at least two sub-frames.

2. The projection screen of claim 1, wherein each sub-frame comprises a connecting plate and a side plate, the side plate is fixedly connected with the connecting plate, the connecting plate surrounds the edge of the fixed frame, and the side plates are stacked on the fixed frame;

the first end of the connecting plate is provided with the first inserting structure, the second end of the connecting plate is provided with the third inserting structure, the first end of the side plate is provided with the second inserting structure, and the second end of the side plate is provided with the fourth inserting structure.

3. The projection screen of claim 2, wherein the first plug structure is a first plug tongue, the third plug structure is a socket, the first plug tongue of the first connector board enters the socket of the second connector board, an end surface of the first plug tongue of the first connector board abuts against a bottom surface of the socket of the second connector board, and a sidewall of the first plug tongue of the first connector board perpendicular to the thickness direction abuts against a sidewall of the socket of the second connector board perpendicular to the thickness direction;

the second plug-in structure includes second tongue and first draw-in groove, the fourth plug-in structure includes third tongue and second draw-in groove, the second tongue butt of inserting of first curb plate is in on the second draw-in groove of second curb plate with thickness direction vertically lateral wall, just the third tongue butt of inserting of second curb plate is in on the first draw-in groove of first curb plate with thickness direction vertically lateral wall.

4. The projection screen of claim 2 wherein the side panel is located on a side of the fixed frame away from the curtain.

5. The projection screen of claim 1 wherein the at least two sub-frames are two in number, both sub-frames being L-shaped.

6. The projection screen of claim 1 wherein the at least two sub-frames are four in number, the four sub-frames each being linear.

7. The projection screen of any one of claims 1-6, wherein the curtain comprises an optical film and a flexible cloth;

the optical membrane is bonded on the flexible cloth, the edge of the flexible cloth is folded from the first side to the second side of the fixed frame, the edge of the flexible cloth is fixed on the second side of the fixed frame through an elastic tensioning piece, and the inner wall of the frame is in clearance contact with the flexible cloth.

8. The projection screen of claim 7 wherein the elastic tension member is a tension spring having a first end coupled to the edge hook of the flexible cloth and a second end coupled to the fixed structure hook of the second side of the fixed frame.

9. A projection screen according to claim 8 wherein the flexible cloth is provided with registration holes and the edges of the optical film are aligned with the registration holes.

10. The projection screen of claim 7 wherein the flexible cloth is a rectangular structure and the corners of the flexible cloth are chamfered.

Technical Field

The application relates to the technical field of projection, in particular to a projection screen.

Background

With the continuous development of science and technology, projection equipment is more and more applied to the work and the life of people. Currently, a projection device mainly includes an optical engine and a projection screen. The light outlet of the optical engine faces the projection screen to emit light beams to the projection screen, and the projection screen is used for reflecting the light beams to realize the display of pictures.

In the related art, the projection screen includes a curtain, a fixing frame and a frame, the curtain is fixed on the fixing frame to fix the curtain, and the frame is fastened at the edges of the curtain and the fixing frame and is fixedly connected with the fixing frame. The frame comprises four sub-frames with U-shaped sections, and the four sub-frames are sequentially fixedly connected end to obtain the rectangular frame.

However, in the related art, the heads and the tails of the four sub-frames are mainly fixedly connected through the fixing members, and the joints of the sub-frames have installation gaps when the sub-frames are connected through the fixing members, so that the frames are easily distorted and deformed under the action of external force, and the curtain is further distorted. Therefore, the picture displayed by the curtain is distorted, and the display effect of the projection screen is reduced.

Disclosure of Invention

The application provides a projection screen, thereby can avoid the frame in the projection screen to take place distortion and warp the phenomenon that leads to the curtain distortion. The technical scheme is as follows:

a projection screen, comprising:

a fixed frame;

the edge of the curtain wraps the fixed frame and is tensioned and fixed on the fixed frame, and the curtain is used for receiving the light beams emitted by the optical engine to display pictures;

the frame comprises at least two sub-frames, a first end part of each sub-frame is provided with a first splicing structure and a second splicing structure, a second end part of each sub-frame is provided with a third splicing structure and a fourth splicing structure, and the at least two sub-frames are spliced in sequence from head to tail based on the first splicing structure, the second splicing structure, the third splicing structure and the fourth splicing structure;

the first inserting structure of the first sub-frame and the third inserting structure of the second sub-frame are in butt joint fixation in the long side direction and the wide side direction of the curtain, the second inserting structure of the first sub-frame and the fourth inserting structure of the second sub-frame are in butt joint fixation in the thickness direction of the curtain, and the first sub-frame and the second sub-frame refer to any two sub-frames to be inserted in the at least two sub-frames.

Optionally, each sub-frame comprises a connecting plate and a side plate, the side plate is fixedly connected with the connecting plate, the connecting plate surrounds the edge of the fixed frame, and the side plates are stacked on the fixed frame;

the first end of the connecting plate is provided with the first inserting structure, the second end of the connecting plate is provided with the third inserting structure, the first end of the side plate is provided with the second inserting structure, and the second end of the side plate is provided with the fourth inserting structure.

Optionally, the first plugging structure is a first plugging tongue, the third plugging mechanism is a slot, the first plugging tongue of the first connecting plate enters the slot of the second connecting plate, the end surface of the first plugging tongue of the first connecting plate abuts against the bottom surface of the slot of the second connecting plate, and the side wall, perpendicular to the thickness direction, of the first plugging tongue of the first connecting plate abuts against the side wall, perpendicular to the thickness direction, of the slot of the second connecting plate;

the second plug-in structure includes second tongue and first draw-in groove, the fourth plug-in structure includes third tongue and second draw-in groove, the second tongue butt of inserting of first curb plate is in on the second draw-in groove of second curb plate with thickness direction vertically lateral wall, just the third tongue butt of inserting of second curb plate is in on the first draw-in groove of first curb plate with thickness direction vertically lateral wall.

Optionally, the side plate is located on a side of the fixed frame away from the curtain.

Optionally, the number of the at least two sub-frames is two, and both the two sub-frames are L-shaped.

Optionally, the number of the at least two sub-frames is four, and the four sub-frames are all linear.

Optionally, the curtain comprises an optical film and a flexible cloth;

the optical membrane is bonded on the flexible cloth, the edge of the flexible cloth is folded from the first side to the second side of the fixed frame, the edge of the flexible cloth is fixed on the second side of the fixed frame through an elastic tensioning piece, and the inner wall of the frame is in clearance contact with the flexible cloth.

Optionally, the elastic tensioning member is a tension spring, a first end of the tension spring is connected with the edge hook of the flexible cloth, and a second end of the tension spring is connected with the fixing structure hook on the second side of the fixing frame.

Optionally, a positioning hole is provided on the flexible cloth, and an edge of the optical film is aligned with the positioning hole.

Optionally, the flexible cloth is of a rectangular structure, and corners of the flexible cloth are designed to be chamfered.

The technical scheme provided by the application has the beneficial effects that at least:

because two at least sub-frames that the frame includes are pegged graft end to end in proper order, and to first sub-frame and the second sub-frame of pegging graft in two at least sub-frames, the first grafting structure of first sub-frame and the third grafting structure of second sub-frame are all the butt fixed on the long limit direction and the broadside direction of curtain, the second grafting structure of first sub-frame and the fourth grafting structure of second sub-frame are fixed on the thickness direction butt of curtain, thereby realize that the butt in the long limit direction, broadside direction and thickness direction are fixed on three direction, the steadiness of frame has been guaranteed, the distortion that probably takes place under the exogenic action has been avoided, and then the possibility that the curtain takes place distortion, the picture display effect of curtain has been improved, also be the picture display effect that has improved projection screen.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a projection screen provided in an embodiment of the present application;

FIG. 2 is a schematic view of a portion of the area a in FIG. 1;

FIG. 3 is a schematic structural diagram of an end portion of a first sub-frame according to an embodiment of the present disclosure;

FIG. 4 is a schematic structural diagram of an end portion of a second sub-frame according to an embodiment of the present disclosure;

FIG. 5 is a schematic structural diagram of a curtain provided in an embodiment of the present application;

FIG. 6 is a schematic diagram illustrating a contracted partial cross-section of a projection screen according to an embodiment of the present disclosure;

FIG. 7 is a schematic diagram illustrating an expanded partial cross-sectional structure of a projection screen according to an embodiment of the present disclosure;

fig. 8 is a schematic structural diagram of a projection screen according to an embodiment of the present application.

Reference numerals:

1: a fixed frame; 2: a curtain; 3: a frame;

21: an optical film; 22: a flexible cloth; 23: an elastic tension member;

221: positioning holes;

31: a sub-frame; 32: a first plug-in structure; 33: a second plug-in structure; 34, a third plug structure; 35: a fourth plug-in structure;

311: a first sub-frame; 312: a second sub-frame; 313: a connecting plate; 314: a side plate;

321: a first tongue; 331: a second tongue; 332: a first card slot; 34: a slot; 351: a third tongue; 352: and a second card slot.

Detailed Description

To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

Fig. 1 illustrates a schematic structural diagram of a projection screen according to an embodiment of the present application, fig. 2 illustrates a schematic structural diagram of a partial enlargement of a region a of the projection screen, fig. 3 illustrates a schematic structural diagram of a first sub-frame according to an embodiment of the present application, and fig. 4 illustrates a schematic structural diagram of a second sub-frame according to an embodiment of the present application. As shown in fig. 1, 2, 3 and 4, the projection screen includes: a fixed frame 1, a curtain 2 and a frame 3; the edge of the curtain 2 wraps the fixed frame 1 and is tensioned and fixed on the fixed frame 1, and the curtain 2 is used for receiving the light beam emitted by the optical engine to display pictures; the frame 3 includes at least two sub-frames 31, and the first end of each sub-frame 31 is provided with first grafting structure 32 and second grafting structure 33, and the second end of each sub-frame 31 is provided with third grafting structure 34 and fourth grafting structure 35, and at least two sub-frames 31 are based on first grafting structure 32, second grafting structure 33, third grafting structure 34 and fourth grafting structure 35 end to end grafting.

The first inserting structure 32 of the first sub-frame 311 and the third inserting structure 34 of the second sub-frame 312 are both fixed in an abutting manner in the long side direction and the wide side direction of the curtain 2, the second inserting structure 33 of the first sub-frame 311 and the fourth inserting structure 35 of the second sub-frame 312 are fixed in an abutting manner in the thickness direction of the curtain 2, and the first sub-frame 311 and the second sub-frame 312 refer to any two sub-frames 31 to be inserted in at least two sub-frames 31.

In the embodiment of the present application, because at least two sub-frames 31 included in the frame 3 are sequentially inserted end to end, and for the first sub-frame 311 and the second sub-frame 312 inserted into the at least two sub-frames 31, the first insertion structure 32 of the first sub-frame 311 and the third insertion structure 34 of the second sub-frame 312 are both fixed in the long side direction and the wide side direction of the curtain 2, the second insertion structure 33 of the first sub-frame 311 and the fourth insertion structure 35 of the second sub-frame 312 are fixed in the thickness direction of the curtain 2, thereby realizing the abutting fixation in the three directions of the long edge direction, the wide edge direction and the thickness direction, ensuring the stability of the frame 3, avoiding the distortion and deformation possibly generated under the action of external force, and then avoided the curtain 2 to take place the possibility of distortion, improved the picture display effect of curtain 2, also improved the picture display effect of projection screen promptly.

The shape of the fixing frame 1 may be rectangular, and the fixing frame 1 may be made of a metal material, so as to improve the structural stability of the fixing frame 1. In addition, the surface of the fixed frame 1 may be a plane, so that after the curtain 2 is fastened and fixed on the fixed frame 1, a planar picture display effect is achieved.

Of course, the shape of the fixing frame 1 may be other shapes as long as it facilitates the tightening and fixing of the curtain 2. The fixing frame 1 may be made of a material other than a metal material as long as the structural stability of the fixing frame 1 can be ensured. Moreover, the surface of the fixing frame 1 may also be a curved surface with a certain radian along the length direction, so that the screen 2 can be tensioned and fixed to realize the image display effect of the curved surface.

In some embodiments, the number of the at least two sub-frames 31 may be two, and the two sub-frames 31 may have the same shape and are both L-shaped, so as to obtain the frame 3 with a rectangular structure by inserting the two L-shaped sub-frames 31.

Of course, the shapes of the two sub-frames 31 may be different, wherein the first sub-frame 311 may have a door-shaped structure, and the second sub-frame 312 may have a linear shape. In order to facilitate the insertion of the two end portions of the first sub-frame 311 and the two end portions of the second sub-frame 312, the sub-frame 31 may be made of a material with a certain elastic deformation, so that the distance between the two end portions of the first sub-frame 311 is expanded under the action of an external force, and the second sub-frame 312 is placed between the two end portions of the first sub-frame 311, thereby realizing the head-to-tail insertion and fixation of the first sub-frame 311 and the second sub-frame 312.

In other embodiments, the number of the at least two sub-frames 31 is four, at this time, the four sub-frames 31 are all linear, and a first pair of sub-frames 31 and a second pair of sub-frames 31 with equal lengths exist in the four sub-frames 31, so that the frame 3 in a rectangular structure can be obtained by inserting the first pair of sub-frames 31 and the second pair of sub-frames 31.

It should be noted that each sub-frame 31 can elastically deform under the action of an external force, so that after the three sub-frames 31 are fixedly inserted, the distance between two ends to be inserted can be expanded under the action of the external force, and the last sub-frame can be conveniently inserted.

In some embodiments, as shown in fig. 2, each sub-frame 31 may include a connection plate 313 and a side plate 314, the side plate 314 is fixedly connected to the connection plate 313, the connection plate 313 surrounds an edge of the fixed frame 1, and the side plate 314 is stacked on the fixed frame 1; a first end of the connection plate 313 is formed with a first plugging structure 32, a second end of the connection plate 313 is formed with a third plugging structure 34, a first end of the side plate 314 is formed with a second plugging structure 33, and a second end of the side plate 314 is formed with a fourth plugging structure 35.

Wherein, because the tip of curb plate 314 need set up the grafting structure for curb plate 314 has certain width, in order to avoid influencing projection screen's whole outward appearance this moment, curb plate 314 can be located one side of keeping away from curtain 2 on fixed frame 1, also be that curb plate 314 can set up the dorsal part at curtain 2, guarantee projection screen's aesthetic property.

It should be noted that, the edge of the connecting plate 313 far from the side plate 314 is formed with a bending plate, that is, the edge of the fixed frame 1 and the curtain 2 is sandwiched between the bending plate and the side plate 314, so as to realize the integral fixing of the bezel 3 with the fixed frame 1 and the curtain 2 through the side plate 314 and the bending plate.

In some embodiments, referring to fig. 3 and 4, the first plugging structure 32 may be a first plugging tongue 321, the third plugging mechanism may be a plugging slot 34, the first plugging tongue 321 of the first connection plate 313 enters the plugging slot 34 of the second connection plate 313, an end surface of the first plugging tongue 321 of the first connection plate 313 abuts against a bottom surface of the plugging slot 34 of the second connection plate 313, and a sidewall, perpendicular to the thickness direction, of the first plugging tongue 321 of the first connection plate 313 abuts against a sidewall, perpendicular to the thickness direction, of the plugging slot 34 of the second connection plate 313.

The first connection plate 313 is a connection plate 313 included in the first sub-bezel, and the second connection plate 313 is a connection plate 313 included in the second sub-bezel 312. Since the end surface of the first tongue 321 of the first connecting plate 313 abuts against the bottom surface of the slot 34 of the second connecting plate 313, the fixing of the bezel 3 in the extending direction of the first tongue 321 can be achieved; since the sidewall of the first tongue 321 of the first connecting plate 313 perpendicular to the thickness direction abuts against the sidewall of the slot 34 of the second connecting plate 313 perpendicular to the thickness direction, the frame 3 can be fixed in the direction perpendicular to the extending direction of the first tongue 321 in the plane of the frame 3, and thus the two directions perpendicular to each other in the plane of the frame 3 are fixed.

Note that, the side wall of the first tongue 321 of the first connecting plate 313 perpendicular to the thickness direction may be a side wall far from the center, or may be a side wall close to the center, as long as the fixing of the frame 3 can be achieved in the direction perpendicular to the extending direction of the first tongue 321 in the plane where the frame 3 is located, which is not limited in the embodiment of the present application.

The first insertion tongue 321 of the first connection plate 313 and the slot 34 of the second connection plate 313 may be in an interference fit to fix the first connection plate 313 in two directions, and further, an adhesive may be applied to the first insertion tongue 321 of the first connection plate 313 to improve the firmness and stability of the fixation between the first insertion tongue 321 of the first connection plate 313 and the slot 34 of the second connection plate 313 through the adhesive on the basis of the interference fit. The extending direction of the first inserting tongue 321 on the first connecting plate 313 may be the length direction of the first connecting plate 313, and correspondingly, the depth direction of the slot 34 on the second connecting plate 313 may be perpendicular to the length direction of the second connecting plate 313; of course, the extending direction of the first tongue 321 of the first connecting plate 313 may be perpendicular to the longitudinal direction of the first connecting plate 313, and the depth direction of the slot 34 of the second connecting plate 313 is the longitudinal direction of the second connecting plate 313.

In some embodiments, referring to fig. 3 and 4, the second plugging structure 33 includes a second plugging tongue 331 and a first plugging groove 332, the fourth plugging structure 35 includes a third plugging tongue 351 and a second plugging groove 352, the second plugging tongue 331 of the first side plate 314 abuts against a side wall perpendicular to the thickness direction on the third plugging tongue 351 of the second side plate 314, and the first plugging groove 332 of the second side plate 314 abuts against a side wall perpendicular to the thickness direction on the second plugging groove 352 of the first side plate 314.

The first side panel 314 refers to a side panel 314 included in the first sub-bezel, and the second side panel 314 refers to a side panel 314 included in the second sub-bezel 312. Since the second tongue 331 of the first side plate 314 abuts against the third tongue 351 of the second side plate 314, and the first groove 332 of the second side plate 314 abuts against the second groove 352 of the first side plate 314, the side wall of the second side plate is perpendicular to the thickness direction, the fixing of the bezel 3 in the thickness direction can be achieved by the dual functions between the second tongue 331 and the third tongue 351, and between the first groove 332 and the second groove 352.

Note that both ends of the first side plate 314 and both ends of the second side plate 314 may be provided with 45-degree chamfers. Of course, the first end of the first side plate 314 is set to be a 30-degree chamfer, and the second end of the second side plate 314 is set to be a 60-degree chamfer, that is, as long as the first end of the first side plate 314 and the second end of the second side plate 314 can be completely matched and can be fixed in an inserting manner, which is not limited in the embodiment of the present application.

In this embodiment, for each sub-frame 31, after the first inserting mechanism, the second inserting structure 33, the third inserting mechanism and the fourth inserting structure 35 are used to realize the end-to-end inserting connection of at least two sub-frames 31, in order to ensure the stability of the connection between the two inserted sub-frames 31, the frame 3 further includes a fixing member and a plurality of fixing screws corresponding to the fixing member. In this way, one end of the fixing element may be fixed to the first sub-frame 311 by at least one first fixing screw of the plurality of fixing screws, and the other end of the fixing element may be fixed to the second sub-frame 312 by at least one second fixing screw of the plurality of fixing screws, so as to achieve further fixed connection between the first sub-frame 311 and the second sub-frame 312.

The fixing member may have an 8-shaped structure or an L-shaped structure, or of course, may have other structures as long as the first sub-frame 311 and the second sub-frame 312 can be connected by the fixing member at the same time, which is not limited in the embodiment of the present application.

The structure and fixing of the curtain 2 will be described next.

In some embodiments, as shown in fig. 5, the curtain 2 may include an optical film 21 and a flexible cloth 22; the optical diaphragm 21 is bonded on the flexible cloth 22, the edge of the flexible cloth 22 is folded from the first side to the second side of the fixed frame 1, the edge of the flexible cloth 22 is fixed on the second side of the fixed frame 1 through the elastic tensioning piece 23, and the inner wall of the frame 3 is in clearance contact with the flexible cloth 22.

Thus, as shown in fig. 6, when the optical film 21 contracts in a low-temperature environment, a contraction force toward the central point is generated, and the flexible cloth 22 is driven to contract synchronously. Since the edge of the flexible cloth 22 is connected to the second side of the fixed frame 1 via the elastic tension member 23, the elastic tension member 23 can be tensioned. In this way, during the slow extension of the elastic tension member 23, it is ensured that the optical film 21 and the flexible cloth 22 are uniformly contracted toward the center, and at the same time, the flat state is maintained, that is, the possibility of distortion of the optical film 21 due to local contraction is avoided. As shown in fig. 7, when the optical film 21 expands in a high temperature environment, a contraction force away from the central point may be generated, so as to drive the flexible cloth 22 to synchronously expand. Because the edge of the flexible cloth 22 is connected with the second side of the fixed frame 1 through the elastic tensioning piece 23, the optical diaphragm 21 and the flexible cloth 22 can be ensured to uniformly expand all around under the slow tensioning action of the elastic tensioning piece 23, and simultaneously, the smooth state is kept, namely, the possibility that the optical diaphragm 21 is distorted and deformed due to local expansion is avoided. In addition, when the optical film 21 and the flexible cloth 22 contract, the elastic stretching member hinders the contraction of the optical film 21 and the flexible cloth 22, thereby reducing the amount of contraction of the optical film 21. Thus, when the edge of the optical film 21 is wrapped by the frame 3, the width of the edge of the frame 3 on the plane where the optical film 21 is located, that is, the width of the bent portion described above, can be reduced appropriately, so as to achieve the effect of removing the frame 3 from the projection screen.

It should be noted that, for the width of the bent portion on the frame 3, the maximum expansion size and the maximum contraction size of the bent portion in a certain temperature range can be calculated through simulation under the action of the elastic tensioning member 23 according to the linear expansion coefficient of the optical film 21, and then the width of the bent portion is determined based on the maximum expansion size and the maximum contraction size, as long as the bent portion can cover the edge of the optical film 21 after the optical film 21 expands or contracts, which is not limited in the embodiment of the present application.

Wherein, the quantity of the elastic tensioning pieces 23 can be 8, two elastic tensioning pieces 23 are correspondingly distributed on each side edge of the flexible cloth 22, and the two elastic tensioning pieces 23 are distributed at two ends of the corresponding side edge. The number of the elastic tensioning pieces 23 can also be 12, at this time, three elastic tensioning pieces 23 are correspondingly distributed on each side edge of the flexible cloth 22, and the three elastic tensioning pieces 23 are distributed at the two ends and the middle part of the corresponding side edge. Of course, the number of the elastic tensioning members 23 may be other values as long as the flexible cloth 22 can be tensioned and fixed, and the embodiment of the present application is not limited thereto.

The optical film 21 may be made of plastic, or of course, may be made of other materials as long as it can receive the light beam emitted from the optical engine and display the image, which is not limited in the embodiment of the present application. The thermal expansion coefficient of the optical film 21 is much higher than that of the fixing frame 1, so as to avoid the phenomenon that the optical film 21 is wrinkled due to the fact that the shrinkage of the fixing frame 1 is larger than that of the optical film 21.

The flexible cloth 22 may be a synthetic cloth, or may be a cloth made of other materials as long as it can contract or expand synchronously with the optical film 21, which is not limited in the embodiment of the present application. The flexible cloth 22 may be a rectangular structure, and the corners of the flexible cloth 22 are all chamfered, so as to avoid the phenomenon of local overlap after the edge of the flexible cloth 22 is folded along the edge of the fixed frame 1, thereby increasing the overall thickness of the projection screen.

It should be noted that, in order to prevent the edge of the optical film 21 from touching the inner wall of the frame 3, when the optical film 21 is bonded to the flexible cloth 22, the size of the optical film 21 may be smaller than the size of the flexible cloth 22, so that it may be ensured that the optical film 21 is completely bonded to the area where the flexible cloth 22 is located, and a safety gap is reserved between the edge of the optical film 21 and the edge of the flexible cloth 22, that is, the minimum distance between the edge of the optical film 21 and the edge of the flexible cloth 22 is greater than the first distance value. The first distance value may be designed according to the width of the flexible cloth 22 folded from the first side to the second side of the fixing frame 1, as long as it is ensured that the edge of the frame 3 including the optical film 21 does not contact with the inner wall of the frame 3.

In addition, because the inner wall of the frame 3 is in clearance contact with the flexible cloth 22, when the optical film 21 drives the flexible cloth 22 to contract or expand synchronously, the flexible cloth 22 can slide between the outer edge of the fixed frame 1 and the inner wall of the frame 3 without hindrance. Wherein, the distance between the inner wall of the frame 3 and the flexible cloth 22 may be greater than a second distance threshold, and the second distance threshold may be designed according to the maximum expandable distance of the flexible cloth 22 in the thickness direction. Illustratively, when the maximum inflatable distance of the flexible cloth 22 in the thickness direction is 0.02mm, the second distance threshold may be 0.025 mm. That is, as long as the second distance threshold is greater than the maximum expandable distance, this is not limited in the embodiments of the present application.

Further, in order to reduce the resistance to relative sliding between the flexible cloth 22 and the fixed frame 1, the edges of the fixed frame 1 may be provided with a lubricating coating. The lubricating coating can reduce friction and avoid abrasion and the like of the flexible cloth 22 after friction between the flexible cloth and the fixed frame 1 for many times.

In some embodiments, the elastic tension member 23 may be a tension spring, a first end of which is hooked with the edge of the flexible cloth 22, and a second end of which is hooked with the fixing structure of the second side of the fixing frame 1.

Wherein, fixed knot constructs can be the fixed column, and the second end of extension spring can hang and realize the couple and connect on the fixed column like this, and of course, as shown in fig. 6 or fig. 7, fixed knot constructs also can be hangs the groove, and the second end of extension spring can be hung and realize the couple and connect in hanging the groove like this.

It should be noted that, when the first end of the tension spring is connected to the flexible cloth 22, in order to avoid the flexible cloth 22 from being broken due to a local over-stress, that is, a stress concentration phenomenon, the edge of the flexible cloth 22, which is located at the first end of the tension spring, and the through hole of the first end of the tension spring is wrapped with the eyelet, so that an acting force of the tension spring acting on the flexible cloth 22 is uniformly distributed at the edge of the through hole through the eyelet, and the stress concentration phenomenon is avoided.

In some embodiments, as shown in fig. 5 or 8, the flexible cloth 22 is provided with positioning holes 221, and the edge of the optical film 21 is aligned with the positioning holes 221.

As shown in fig. 5, each corner position of the flexible cloth 22 is provided with a pair of positioning holes 221, so as to position the corresponding corner on the optical film 21 through the pair of positioning holes 221, thereby ensuring that the normal center line of the optical film 21 coincides with the normal center line of the flexible cloth 22, and further ensuring the accuracy of the bonding position of the optical film 21.

In addition, after the flexible cloth 22 is bonded to the optical film 21, when the flexible cloth 22 is fixed to the fixed frame 1, as shown in fig. 8, the relative position between the flexible cloth 22 and the fixed frame 1 can be ensured based on the positioning hole 221 on the flexible cloth 22, and the normal center direction of the optical film 21 can be ensured to be overlapped with the normal center line of the fixed frame 1, so as to ensure that the picture displayed on the whole projection screen is located at the center of the projection screen, thereby improving the picture display effect of the projection screen. Because the normal direction central line coincidence of the normal direction central line of optical film 21 and fixed frame 1, the distance between the edge of optical film 21 and fixed frame 1 is more uniformized like this to when setting up frame 3, can guarantee that the width of every side of frame 3 equals to the width of the less frame 3 of maximize whole.

In the embodiment of the application, to the first sub-frame and the second sub-frame of waiting to peg graft in at least two sub-frames, the first grafting structure of first sub-frame and the third grafting structure of second sub-frame are all the butt fixed on the long limit direction and the broadside direction of curtain, the second grafting structure of first sub-frame and the fourth grafting structure of second sub-frame are fixed on the thickness direction butt of curtain, thereby realize at long limit direction, butt on broadside direction and the three direction of thickness direction is fixed, the steadiness of frame has been guaranteed, the distortion that probably takes place under the exogenic action has been avoided, and then the possibility that the curtain takes place the distortion has been avoided, the picture display effect of curtain has been improved, also be the picture display effect that has improved projection screen. In addition, because the optical film that the curtain includes bonds on flexible cloth, flexible cloth elasticity is taut on fixed frame to can reduce the shrink size of optical film through elastic stretching piece when optical film contracts, thereby can reduce the side size of frame, realize the effect of super narrow frame, improve projection screen's pleasing to the eye degree.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.