Projection screen

Abstract

This application discloses a projection screen, belonging to the field of projection display. The projection screen includes a roll, a screen panel, and multiple support strips. The multiple support strips, fixedly connected to the back of the screen panel, are arranged along the rolling direction of the screen panel, and the ratio between the thermal expansion coefficient of the screen panel and the thermal expansion coefficient of the support strips is less than or equal to a target threshold, meaning the thermal expansion coefficients of the screen panel and the support strips are close. Thus, when the projection screen is in a high-temperature environment, the degree of thermal expansion of the screen panel is similar to the degree of thermal expansion of the support strips. Furthermore, when the screen panel is connected to the support strips, the pressure exerted on the multiple support strips after thermal expansion is relatively small, resulting in less buckling deformation of the support strips. This allows the multiple support strips to effectively support the screen panel, thereby reducing the probability of edge curling or internal unevenness of the screen panel after repeated unfolding and retraction.

Description

Technical Field

[0001] This application relates to the field of projection display, and in particular to a projection screen. Background Technology

[0002] With the development of technology, laser projection systems are increasingly being used in people's work and daily lives. Currently, laser projection systems mainly consist of a projection screen and a projection device. The projection device projects a beam of light onto the projection screen to display the projected image.

[0003] A projection screen typically includes a screen panel, a roll-up mechanism, and a lifting mechanism. One side of the screen panel is connected to the roll-up mechanism, and the other side is connected to the lifting mechanism. The roll-up mechanism allows the screen panel to be retracted, and the lifting mechanism allows it to be extended.

[0004] However, after repeated unfolding and retraction, the screen is prone to edge curling or internal unevenness, which can lead to distortion of the projected image and poor display quality. Summary of the Invention

[0005] This application provides a projection screen. It solves the problem of poor display quality of projected images on existing projection screens. The technical solution is as follows:

[0006] On one hand, a projection screen is provided, the projection screen comprising:

[0007] Roller, screen, and multiple support bars;

[0008] The roller is fixedly connected to the first side of the curtain sheet;

[0009] At least a portion of the screen can be rolled up and wound onto the roll, and the front side of the screen is used to display the projected image;

[0010] The plurality of support strips are all fixedly connected to the back of the curtain sheet, and the plurality of support strips are arranged along the curling direction of the curtain sheet;

[0011] Wherein, the ratio between the thermal expansion coefficient of the curtain sheet and the thermal expansion coefficient of the support strip is less than or equal to the target threshold.

[0012] The beneficial effects of the technical solutions provided in this application include at least the following:

[0013] A projection screen may include a roll, a screen panel, and multiple support strips. The multiple support strips, fixedly connected to the back of the screen panel, are arranged along the rolling direction of the screen panel, and the ratio between the thermal expansion coefficient of the screen panel and the thermal expansion coefficient of the support strips is less than or equal to a target threshold, meaning the thermal expansion coefficients of the screen panel and the support strips are close. Thus, when the projection screen is in a high-temperature environment, the degree of thermal expansion of the screen panel is similar to that of the support strips. Furthermore, when the screen panel is connected to the support strips, the pressure exerted on the support strips after thermal expansion is relatively small, resulting in less buckling deformation of the support strips. This allows the multiple support strips to effectively support the screen panel, thereby reducing the probability of edge curling or internal unevenness of the screen panel after repeated unfolding and retraction. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a rendering of a linear cursor image shown in the related technology when the screen is not heated and expanded;

[0016] Figure 2 It is a rendering of a linear cursor image produced when a screen expands due to heat, as shown in related technologies;

[0017] Figure 3 This is a rear view of a projection screen provided in an embodiment of this application;

[0018] Figure 4 This is a side view of a projection screen provided in an embodiment of this application;

[0019] Figure 5 yes Figure 3 The image shown is an effect of a linear cursor image displayed when the screen is not heated and expanded.

[0020] Figure 6 yes Figure 3 The image shown is an effect of a linear cursor image produced when the screen expands due to heat.

[0021] Figure 7 This is a side view of another projection screen provided in an embodiment of this application;

[0022] Figure 8 This is a side view of another projection screen provided in the embodiments of this application;

[0023] Figure 9 This is a side view of another projection screen provided in an embodiment of this application;

[0024] Figure 10 This is a side view of a projection screen provided in another embodiment of this application;

[0025] Figure 11 This is a side view of yet another projection screen provided in another embodiment of this application;

[0026] Figure 12 This is a schematic diagram of the structure of a projection screen provided in an embodiment of this application;

[0027] Figure 13 This is a schematic diagram illustrating the connection between a tension rope and a support bar, provided in an embodiment of this application.

[0028] Figure 14 This is a schematic diagram of the connection between a support strip and a curtain sheet provided in an embodiment of this application;

[0029] Figure 15 This is a diagram showing the screen when it unfolds;

[0030] Figure 16 This is a schematic diagram of the structure of a laser projection device provided in an embodiment of this application;

[0031] Figure 17 This is a schematic diagram of another laser projection device provided in an embodiment of this application.

[0032] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0034] In related technologies, to prevent edge curling or internal unevenness of the screen 10 after repeated unfolding and retraction by lifting and rolling mechanisms, multiple support strips 20 can be provided on the back of the screen 10. However, the thermal / humidity expansion coefficient of the support strips 20 is much smaller than that of the screen 10. For example, when the support strips 20 are carbon fiber sheets, the thermal expansion coefficient of the carbon fiber sheets is typically 0.57 microstrain / degree, while that of the screen 10 is typically 60 microstrain / degree. Thus, when the projection screen 00 is in a high-temperature environment, the degree of thermal expansion of the screen 10 in the projection screen 00 is much greater than that of the carbon fiber sheets. When the screen 10 is connected to the carbon fiber sheets, the thermal expansion of the screen 10 applies pressure to the multiple carbon fiber sheets with smaller expansion, causing the carbon fiber sheets to buckle and deform, resulting in poor flatness on the front side of the screen 10 connected to the carbon fiber sheets. The projected image displayed on the front of the screen 10 still exhibits distortion and other defects, resulting in a poor display quality. However, to reduce the deformation of the screen during thermal expansion of the screen 10 and the carbon fiber sheet, the distance between any two adjacent carbon fiber sheets is typically set relatively large. However, this limits the improvement in flatness to a smaller area of ​​the screen 10, thus restricting the overall strength improvement effect of the carbon fiber sheet on the screen 10.

[0035] For example, please refer to Figure 1 and Figure 2 , Figure 1 This is a rendering of a linear cursor image shown in the related technology when the screen is not heated and expanded. Figure 2 This is a diagram illustrating the linear cursor image produced when the projection screen 10 expands due to heat, as shown in related technologies. When the projection screen 00 is not heated and expanded, each support bar 20 effectively supports the screen 10, ensuring good flatness of the front surface of the screen 10, and the cursor image 30 displayed on the screen 10 does not exhibit significant distortion. When the projection screen 00 expands due to heat, each support bar 20 buckles and deforms under the influence of the thermal expansion of the screen 10, resulting in poor flatness of the front surface of the screen 10, and significant distortion of the cursor image 30 displayed on the screen 10.

[0036] Please refer to Figure 3 and Figure 4 , Figure 3 This is a rear view of a projection screen provided in an embodiment of this application. Figure 4 This is a side view of a projection screen provided in an embodiment of this application. The projection screen 000 may include: a roll 100, a screen 200, and multiple support strips 300.

[0037] The roll 100 in the projection screen 000 can be fixedly connected to the first side of the screen 200.

[0038] At least a portion of the screen 200 in the projection screen 000 can be rolled and wound onto the roll 100, and the front of the screen 200 can be used to display the projected image.

[0039] Multiple support bars 300 in the projection screen 000 can be fixedly connected to the back of the screen 200, and the multiple support bars 300 can be arranged along the curling direction of the screen 200.

[0040] In this embodiment, the ratio between the coefficient of thermal expansion of the screen 200 in the projection screen 000 and the coefficient of thermal expansion of the support strip 300 fixed to the back of the screen 200 can be less than or equal to a target threshold. For example, when the ratio between the coefficient of thermal expansion of the screen 200 and the support strip 300 is less than or equal to the target threshold, the target threshold can be 3. It should be noted that in practical applications, different target thresholds can be selected depending on the size of the screen 200 and the diameter of the roller 100 used to roll up the screen 200. This embodiment does not impose specific limitations on this.

[0041] In this embodiment, multiple support strips 300 fixedly connected to the back of the screen 200 are arranged along the curling direction of the screen 200, and the ratio between the thermal expansion coefficient of the screen 200 and the thermal expansion coefficient of the support strips 300 is less than or equal to a target threshold, i.e., the thermal expansion coefficient of the screen 200 is close to that of the support strips 300. Thus, when the projection screen 000 is in a high-temperature environment, the degree of thermal expansion of the screen 200 is similar to that of the support strips 300. When the screen 200 is connected to the support strips 300, the pressure exerted on the multiple support strips 300 after thermal expansion is relatively small, resulting in less buckling deformation of the support strips 300. This allows the multiple support strips 300 to effectively support the screen 200, thereby reducing the probability of edge curling or internal unevenness of the screen 200 after repeated unfolding and retraction. In this application, the thickness of the support strip 300 can be greater than the thickness of the screen 200 in the direction perpendicular to the back of the screen 200. This ensures that the structural strength and bending stiffness of the support strip 300 are greater than those of the screen 200, thus guaranteeing that the support strip 300 can effectively support the screen 200. This, in turn, ensures better flatness of the front of the screen 200, effectively reducing the probability of distortion and other defects in the projected image displayed on the front of the screen 200.

[0042] For example, please refer to Figure 5 and Figure 6 , Figure 5 yes Figure 3The image shown is an illustration of a linear cursor when the screen is not thermally expanded. Figure 6 yes Figure 3 The diagram shows the effect of a linear cursor image produced when the screen panel 200 expands due to heat. When the screen panel 200 is not expanded by heat, each support bar 300 effectively supports the screen panel 200, ensuring good flatness of the front surface of the screen panel 200. A long cursor image A1 is projected onto the screen panel 200 in a direction perpendicular to the length of the support bars 300; the long cursor image A1 shows no obvious distortion. When the screen panel 200 and support bars 300 expand due to heat / moisture, the buckling deformation of the screen panel 200 is similar to that of the support bars 300, ensuring that the support bars 300 can effectively support the screen panel 200, thus maintaining good flatness of the front surface of the screen panel 200. A long cursor image A1 is projected onto the screen panel 200 in a direction perpendicular to the length of the support bars 300; the long cursor image A1 also shows no obvious distortion.

[0043] It should be noted that, as Figure 3 As shown, since the coefficients of thermal expansion of the screen panel 200 and the support strips 300 are similar, the spacing between any two adjacent support strips 300 on the back of the screen panel 200 can be made smaller. This effectively improves the flatness of most areas of the screen panel 200.

[0044] In summary, this application provides a projection screen that may include a roll, a screen panel, and multiple support strips. The multiple support strips, fixedly connected to the back of the screen panel, are arranged along the rolling direction of the screen panel, and the ratio between the thermal expansion coefficient of the screen panel and the thermal expansion coefficient of the support strips is less than or equal to a target threshold, meaning the thermal expansion coefficients of the screen panel and the support strips are close. Thus, when the projection screen is in a high-temperature environment, the degree of thermal expansion of the screen panel is similar to the degree of thermal expansion of the support strips. Furthermore, when the screen panel is connected to the support strips, the pressure exerted on the multiple support strips after thermal expansion is relatively small, resulting in less buckling deformation of the support strips. This allows the multiple support strips to effectively support the screen panel, thereby reducing the probability of edge curling or internal unevenness of the screen panel after repeated unfolding and retraction.

[0045] Optional, please refer to Figure 7 , Figure 7This is a side view of another projection screen provided in an embodiment of this application. The screen panel 200 and support strips 300 in the projection screen 000 can be integrally formed. In this case, the screen panel 200 and support strips 300 can be formed simultaneously through a single injection molding process. This effectively simplifies the connection process between the screen panel 200 and the multiple support strips 300 in the projection screen 000, and effectively ensures the connection accuracy between the screen panel 200 and the multiple support strips 300.

[0046] In the embodiments of this application, please refer to Figure 8 , Figure 8 This is a side view of another projection screen provided in this application embodiment. The projection screen 000 may further include a connecting portion 400 located between the screen panel 200 and the support bars 300, which can be fixedly connected to the back surface of the screen panel 200 and the plurality of support bars 300 respectively. In the direction perpendicular to the back surface of the screen panel 200, the thickness of the connecting portion 400 may be less than the thickness of the screen panel 200 and may be less than the thickness of the support bars 300. In this case, by providing the connecting portion 400 between the screen panel 200 and the support bars 300 to fix the plurality of support bars 300 to the back surface of the screen panel 200, the screen panel 200 and the support bars 300 can be manufactured separately and then assembled together by a connection process without changing the organizational state and performance of the screen panel 200 and the support bars 300. Furthermore, the thickness of the connecting portion 400 is less than the thickness of the screen panel 200 and less than the thickness of the support strip 300. This ensures that when the screen panel 200, the connecting portion 400, and the support strip 300 are in a high-temperature environment, even if the connecting portion 400 undergoes thermal expansion, the impact on the screen panel 200 is minimal. This, in turn, ensures the flatness of the screen panel 200.

[0047] Optionally, the connecting portion 400 in the projection screen 000 may include: a connecting piece 401 of the entire layer, and at least a portion of the support bars 300 whose orthogonal projections on the back of the screen 200 are located within the orthogonal projection of the connecting piece 401 on the back of the screen 200.

[0048] And / or, the connecting portion 400 may include a plurality of connecting strips 402, which may correspond one-to-one with at least a portion of the plurality of support strips 300. The orthographic projection of each connecting strip 402 on the back side of the screen 200 may lie within the orthographic projection of the corresponding support strip 300 on the back side of the screen 200.

[0049] As can be seen from the above, there are multiple possible implementations for the structure of the connecting part 400, which is connected to both the curtain panel 200 and the multiple support bars 300. This application embodiment illustrates the following three possible implementations as examples:

[0050] The first optional implementation method, such as Figure 8 As shown, the connecting part 400 may include: a connecting piece 401 arranged in a single layer; the orthographic projections of multiple support strips 300 located on the back of the screen 200 on the back of the screen 200 are all located within the orthographic projection of the connecting piece 401 on the back of the screen 200. In this case, by fixing the multiple support strips 300 to the back of the screen 200 through the connecting piece 401 arranged in a single layer, the contact area between the support strips 300 and the screen 200 is larger, effectively increasing the structural strength and bending stiffness of the entire area of ​​the screen 200. Consequently, after the screen 200 is unfolded, the probability of edge curling or internal unevenness is lower, ensuring a better display effect of the projected image on the screen 200. In addition, the connecting piece 401 arranged in a single layer is directly connected to the back of the screen 200, and the multiple support strips 300 are fixed to the side of the connecting piece 401 opposite to the screen 200. This simplifies the assembly process of the support strip 300 and the screen panel 200, and ensures the assembly accuracy of multiple support strips 300 and screen panels 200. It should be noted that the orthographic projection of the connecting piece 401 on the back of the screen panel 200 is located within the area of ​​the back of the screen panel 200.

[0051] For the second optional implementation method, please refer to... Figure 9 , Figure 9 This is a side view of another projection screen provided in an embodiment of this application. The connecting part 400 may include a plurality of connecting strips 402, which may correspond one-to-one with a plurality of support strips 300 located on the back of the screen 200. The orthographic projection of each connecting strip 402 on the back of the screen 200 may lie within the orthographic projection of the corresponding support strip 300 on the back of the screen 200. In this case, by setting a one-to-one connection between the plurality of connecting strips 402 and the plurality of support strips 300, the assembly flexibility of each support strip 300 to the back of the screen 200 is ensured, and the overall weight of the connecting part 400 is reduced, resulting in a smaller overall weight of the projection screen 000.

[0052] For the third optional implementation method, please refer to... Figure 10 , Figure 10This is a side view of a projection screen provided in another embodiment of this application. The connecting portion 400 includes: a connecting piece 401 of one layer and a plurality of connecting strips 402. The orthographic projection of a portion of the plurality of support strips 300 located on the back side of the screen 200 onto the back of the screen 200 can lie within the orthographic projection of the connecting piece 401 onto the back of the screen 200. Each of the plurality of connecting strips 402 corresponds one-to-one with another portion of the plurality of support strips 300, and the orthographic projection of each connecting strip 402 onto the back of the screen 200 can lie within the orthographic projection of the corresponding support strip 300 onto the back of the screen 200. For example, as... Figure 10 As shown, the back surface of the screen panel 200 includes a first region A2 and a second region A3 arranged adjacent to each other along the curling direction of the screen panel 200. A continuous connecting piece 401 in the connecting portion 400 can be disposed within the second region A3 on the back surface of the screen panel 200, and multiple connecting strips 402 are disposed within the first region A2 on the back surface of the screen panel 200. After the screen panel 200 is retracted, typically a portion of the screen panel 200 is wound onto the roller 100, while another portion is not wound onto the roller 100. The first region A2 can be the area containing the back surface of the screen panel 200 wound onto the roller 100, and the second region A3 can be the area containing the back surface of the screen panel 200 not wound onto the roller 100. Thus, when the curtain 200 needs to be retracted, the part of the curtain 200 connected to the multiple connecting strips 402 can be rolled up on the roller 100 more easily, while the part of the curtain 200 connected to the connecting piece 401 of the whole layer has good overall structural strength and bending stiffness, ensuring that the flatness of this part of the curtain 200 is good.

[0053] In the embodiments of this application, such as Figure 9 As shown, when the connecting part 400 includes multiple connecting strips 402, the width of each connecting strip 402 can be smaller than the width of the corresponding support strip 300. Furthermore, the orthographic projection of each connecting strip 402 on the back of the screen 200 can be located in the central area of ​​the orthographic projection of the corresponding support strip 300 on the back of the screen 200. In this case, by setting the width of each connecting strip 402 to be smaller than the width of the corresponding support strip 300, while ensuring support for the screen 200 by the support strips 300, the contact area between each support strip 300 and the screen 200 is small, making it easier for the screen 200 to be wound onto the roll 100 when retracted. Furthermore, by positioning the orthographic projection of each connecting strip 402 on the back of the screen 200 within the central region of the orthographic projection of the corresponding support strip 300 on the back of the screen 200, the distribution of the supporting force applied by the support strips 300 to the area on the back of the screen 200 connected to the multiple support strips 300 is made more uniform, thereby ensuring the overall flatness of the screen 200. For example, as... Figure 10As shown, multiple support strips 300 and multiple connecting strips 402 are provided in the first region A2 on the back of the screen 200. The width of each connecting strip 402 may be smaller than the width of the corresponding support strip 300. The first region A2 can be the region where the back of the screen 200 is wound on the roller 100, and the second region A3 can be the region where the back of the screen 200 is not wound on the roller 100.

[0054] Optionally, the connecting portion 400, which connects to the back surface of the screen panel 200 and the support strip 300 respectively, can be an adhesive layer or a magnetic sheet 400a. In this case, multiple support strips 300 can be fixed to the back surface of the screen panel 200 by means of adhesive layer bonding or by means of magnetic connection of magnetic sheet 400a. For example, the adhesive layer can be any one of double-sided tape, liquid adhesive, or foam adhesive, and this application embodiment does not specifically limit it.

[0055] In the embodiments of this application, please refer to Figure 11 , Figure 11 This is a side view of another projection screen provided in another embodiment of this application. When the connecting part 400 can be a magnetic sheet 400a, the support strip 300 can include: a support strip body a1, and metal particles a2 distributed within the support strip body a1. In this case, by integrating the metal particles a2 within the support strip body a1 and using the magnetic sheet 400a as the connecting part 400, the support strip 300 can be attracted to the back of the screen 200 by the magnetic sheet 400a. The side of the magnetic sheet 400a facing away from the support strip 300 can be bonded to the back of the screen 200, or magnetic powder (not shown in the figure) or other particles can be integrated into the screen 200 to attract the magnetic sheet 400a to the back of the screen 200. This embodiment of the application does not specifically limit this.

[0056] Optional, please refer to Figure 12 and Figure 13 , Figure 12 This is a schematic diagram of the structure of a projection screen provided in an embodiment of this application. Figure 13This is a schematic diagram illustrating the connection between a tension rope and a support bar according to an embodiment of this application. The projection screen 000 may further include: a base 500, a lifting mechanism 600, and a tension rope 700. Both the roller 100 and the lifting mechanism 600 in the projection screen 000 can be fixed to the base 500. The lifting mechanism 600 may include a crossbeam 601, which can be fixedly connected to the second side of the screen 200. The lifting mechanism 600 can be configured to control the unfolding of the portion of the screen 200 wound on the roller 100 via the crossbeam 601. The first and second sides of the screen 200 can be two opposite sides of the screen 200 along the curling direction of the screen 200. The tension rope 700 in the projection screen 000 can be sequentially fixedly connected to multiple support bars 300. After the lifting mechanism 600 unfolds the screen 200, the tension rope 700 can be connected to the base 500 and the crossbeam 601 respectively. The tension rope 700 can also be disengaged from at least one of the base 500 and the crossbeam 601 before the drum 100 winds up the curtain 200. In this case, when the curtain 200 needs to be unfolded, the lifting mechanism 600 can control the crossbeam 601 to move, thereby driving the second side of the curtain 200 to move, so as to unfold the curtain 200.

[0057] Furthermore, after the curtain panel 200 is unfolded, the two ends of the tension rope 700, which is fixedly connected to the multiple support bars 300, can be fixedly connected to the crossbeam 601 and the base 500 respectively, keeping the tension rope 700 taut. This tensioning effect on the curtain panel 200 further ensures the overall flatness of the curtain panel 200. When the curtain panel 200 needs to be retracted, the tension rope 700 is first disconnected from at least one of the base 500 and the crossbeam 601, allowing the tension rope 700 to relax without affecting the curling of the curtain panel 200. For example, elongated holes (not shown in the figure) can be made through each of the multiple support bars 300, and the tension rope 700 can be connected to the multiple support bars 300 after passing through the multiple elongated holes. This ensures a better appearance on the back of the curtain panel 200.

[0058] In this application, the number of tension cords 700 can be one or more, and the length direction of the tension cords 700 is perpendicular to the length direction of the multiple supports 300. For example, when there is one tension cord 700, it can be placed in the middle of the back of the screen panel 200. The number of tension cords 700 can also be three: one tension cord 700 on each of the two sides of the back of the screen panel 200, and one tension cord 700 in the middle of the back of the screen panel 200.

[0059] In this embodiment, the screen 200 in the projection screen 000 can be a sheet structure made of polyethylene terephthalate (PET), and the support strip 300 in the projection screen 000 can be a strip structure made of PET. It should be noted that in practical applications, the thickness, width, and distance between any two adjacent support strips 300 can be set according to the size and winding diameter of the screen 200.

[0060] It should also be noted that in practical applications, the portion of the screen 200 wound on the roll 100 is prone to creep, while the portion not wound on the roll 200 has a lower probability of creep. Therefore, support strips 300 can be omitted or the distance between adjacent support strips 300 can be increased in the area on the back of the screen 200 not wound on the roll 100. This reduces the number of support strips 300 used, thereby reducing the overall weight of the projection screen 000.

[0061] It should be noted that, in other possible implementations, the screen 200 and the support strip 300 in the projection screen 000 can also be made of other materials, such as the same material or different materials, as long as the coefficient of thermal expansion of the screen 200 and the coefficient of thermal expansion of the support strip 300 are similar. This application embodiment does not make specific limitations in this regard.

[0062] Optional, please refer to Figure 14 , Figure 14 This is a schematic diagram illustrating the connection between a support strip and a screen according to an embodiment of this application. At least a portion of the plurality of support strips 300 in the projection screen 000 can be solid structures, and / or at least a portion of the plurality of support strips 300 can be hollow structures. For example, all of the plurality of support strips 300 can be hollow structures; or, all of the plurality of support strips 300 can be solid structures; or a portion of the plurality of support strips 300 can be hollow structures, and another portion can be solid structures. This embodiment of the application does not specifically limit this. In this application, as... Figure 14 As shown, when the support bar 300 is a hollow structure, a reinforcing rib 301 can be provided in the cavity of the support bar 300 to reinforce the support bar 300. For example, the shape of the reinforcing rib 301 can be a strip, a crescent shape, or other shapes, and this application embodiment does not specifically limit it.

[0063] During the use of the screen 200, the screen 200 needs to be unfolded and retracted multiple times. In order to reduce the probability of the screen 200 having defects such as edge curling or unevenness, this application adopts a support strip 300 with a coefficient of thermal expansion close to that of the screen 200, which is arranged on the back of the screen 200 and fixedly connected to the back of the screen 200.

[0064] To prevent localized deformation of the curtain panel 200 during its roll-up, a good fit between the curtain panel 200 and the roller 100 is required. This necessitates that the support strips 300 have a small thickness h, a small width w, and a large spacing d between adjacent support strips 300. Therefore, it is necessary to ensure the maximum principal strain ε of the curtain panel 200 is within acceptable limits. principal The principal strain of failure [ε] is less than 200 mm.

[0065] When the screen 200 is unfolded, it is necessary to ensure that the image projected onto the screen 200 by the projector has a good effect. This requires that the support strip 300 has a large thickness h, the support strip 00 has a large width w, and the distance d between two adjacent support strips 300 is small. To this end, it is necessary to ensure that the maximum value of the out-of-plane displacement deformation (the maximum displacement of the screen before and after deformation) of the screen 200 under the combined action of its own weight and wind pressure is max u3, that is, to minimize the maximum value of the out-of-plane displacement deformation max u3.

[0066] This application's embodiments are intended to illustrate the influence of the width, thickness, and distance between adjacent support strips on the maximum out-of-plane displacement deformation of the curtain sheet. Please refer to... Figure 15 , Figure 15 This is a schematic diagram of the curtain when it is unfolded. The example here uses PET strips as support bars. The design variables are the width w, thickness h, and distance d between adjacent PET strips. The objective function is to minimize the maximum out-of-plane displacement (max u3) of the curtain in the unfolded state, and the maximum principal strain (ε) of the curtain in the rolled-up state. principal The allowable principal strain [ε] less than 200 mm of the screen is used as the optimization constraint. The optimization problem can be formulated as follows:

[0067] find para = [w, d, h]

[0068] min(max u3)

[0069] stε principai <[ε]

[0070] In summary, this application provides a projection screen that may include a roll, a screen panel, and multiple support strips. The multiple support strips, fixedly connected to the back of the screen panel, are arranged along the rolling direction of the screen panel, and the ratio between the thermal expansion coefficient of the screen panel and the thermal expansion coefficient of the support strips is less than or equal to a target threshold, meaning the thermal expansion coefficients of the screen panel and the support strips are close. Thus, when the projection screen is in a high-temperature environment, the degree of thermal expansion of the screen panel is similar to the degree of thermal expansion of the support strips. Furthermore, when the screen panel is connected to the support strips, the pressure exerted on the multiple support strips after thermal expansion is relatively small, resulting in less buckling deformation of the support strips. This allows the multiple support strips to effectively support the screen panel, thereby reducing the probability of edge curling or internal unevenness of the screen panel after repeated unfolding and retraction.

[0071] Please refer to Figure 16 , Figure 16 This is a schematic diagram of a laser projection device provided in an embodiment of this application. The laser projection device may include: a projection screen 000 and a projection host 001. The projection screen 000 may be any of the projection screens shown above.

[0072] In the embodiments of this application, please refer to Figure 17 , Figure 17 This is a schematic diagram of another laser projection device provided in an embodiment of this application. The projection device may further include a storage section 002 for storing the projector 001 and the projection screen 000. The storage section 002 may have a light-transmitting area 0021 and an opening 0022. The light beam emitted from the projector 001 can pass through the light-transmitting area 0021, and the lifting mechanism 600 can control the screen 200 to pass through the opening 0022 and unfold. In this way, when the projection device is not in use, the projector 001 and the projection screen 000 are stored in the storage section 002, which saves space. When the projection device is in use, the lifting mechanism 600 controls the screen 200 to unfold, and at the same time, the projector 001 projects a light beam onto the screen 200 so that the screen 200 displays the projected image.

[0073] Specifically, the vertical distance from the center point of the light-transmitting area 0021 to the plane where the unfolded screen 200 is located is equal to the product of the projection ratio of the projector and the width of the display area on the screen. The width of the display area refers to the dimension of the display area along the horizontal direction. This ensures that the light beam emitted by the projector 001 can be accurately projected onto the display area of ​​the screen 200, thereby guaranteeing the clarity of the projected image on the screen 200.

[0074] Since the throw ratio is a performance parameter of the projector 001 itself, its throw ratio is related to the selected projector 001. That is, different projectors 001 will result in different throw ratios, and consequently, different vertical distances from the center point of the light-transmitting area 0021 to the plane where the unfolded screen 200 is located. Therefore, in actual setup, the vertical distance from the center point of the light-transmitting area 0021 to the plane where the unfolded screen 200 is located is calculated using the throw ratio of the projector 001 and the width of the display area. This ensures that the light beam emitted by the projector 001 can be completely projected onto the display area of ​​the screen 200.

[0075] Optionally, the projector 001 can be an ultra-short-throw projector, which can be a DLP (Digital Light Processing) projector. This allows for a shorter distance between the projector 001 and the plane containing the projection screen 000, enabling a miniaturized design of the entire projection device. The projector 001 may include a light source, an optical engine, and a lens (not shown in the figure). The light source emits a light beam to the optical engine.

[0076] The optical engine may include a Digital Micromirror Device (DMD) and a drive circuit board electrically connected to the DMD. The drive circuit board in the optical engine provides a drive signal to the DMD. The DMD can then modulate the light beam emitted from the light source based on the drive signal, and output the modulated beam to a lens. The beam is then output through the lens to the screen 200 on the projection screen 000, enabling the screen 200 to display a projected image. For example, the projection host 001 includes an ultra-short-throw projection lens.

[0077] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.

[0078] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A projection screen, characterized in that, include: Roller, screen, and multiple support bars; The roller is fixedly connected to the first side of the curtain sheet; At least a portion of the screen can be rolled up and wound onto the roll, and the front side of the screen is used to display the projected image; The plurality of support strips are all fixedly connected to the back of the curtain sheet, and the plurality of support strips are arranged along the curling direction of the curtain sheet; Wherein, the difference between the thermal expansion coefficient of the curtain sheet and the thermal expansion coefficient of the support strip is less than or equal to the target threshold; The screen and the support strip are integrally formed; or, the projection screen further includes: a connecting part located between the screen and the support strip, the connecting part being fixedly connected to the back of the screen and the plurality of support strips respectively, and in the direction perpendicular to the back of the screen, the thickness of the connecting part is less than the thickness of the screen and less than the thickness of the support strip. The projection screen also includes: a base, a lifting mechanism, and a tensioning rope; Both the roller and the lifting mechanism are fixed on the base. The lifting mechanism includes a crossbeam, which is fixedly connected to the second side of the curtain. The second side and the first side are two opposite sides of the curtain. The lifting mechanism is configured to control the unfolding of the portion of the curtain wound on the roller through the crossbeam. The tension ropes are sequentially fixedly connected to the plurality of support bars. The tension ropes can be connected to the base and the crossbeam respectively after the lifting mechanism unfolds the curtain, so that the tension ropes are in a taut state. The tension ropes can also be disconnected from at least one of the base and the crossbeam before the drum rolls up the curtain, so that the tension ropes are in a slack state.

2. The projection screen according to claim 1, characterized in that, The connecting part includes: a connecting piece of the whole layer, and at least some of the support bars of the plurality of support bars have their orthographic projections on the back of the curtain sheet located within the orthographic projection of the connecting piece on the back of the curtain sheet; And / or, the connecting part includes: a plurality of connecting strips, the plurality of connecting strips corresponding one-to-one with at least a portion of the plurality of support strips, and the orthographic projection of each connecting strip on the back of the curtain sheet is located within the orthographic projection of the corresponding support strip on the back of the curtain sheet.

3. The projection screen according to claim 2, characterized in that, When the connecting part includes: When there are multiple connecting strips, the width of each connecting strip is smaller than the width of the corresponding support strip, and the orthographic projection of each connecting strip on the back of the curtain is located in the central area of ​​the orthographic projection of the corresponding support strip on the back of the curtain.

4. The projection screen according to any one of claims 1 to 3, characterized in that, The connecting part is an adhesive layer with adhesive properties or a magnetic sheet with magnetic properties.

5. The projection screen according to claim 4, characterized in that, When the connecting part is the magnetic sheet, the support bar includes: a support bar body and metal particles distributed within the support bar body.

6. The projection screen according to any one of claims 1 to 3, characterized in that, The curtain sheet is a sheet structure made of polyethylene terephthalate (PET), and the support strip is a strip structure made of PET.

7. The projection screen according to claim 6, characterized in that, At least a portion of the plurality of support bars is a solid structure, and / or at least a portion of the plurality of support bars is a hollow structure.

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