Projection screen and projection screen convergence point change fitting method

Abstract

The present invention discloses a projection screen equipped with a microstructure layer for converging projection light. The microstructure layer comprises a plurality of unit lenses with sawtooth-shaped cross sections arranged concentrically in the plane of the projection screen. Each unit lens converges the projection light to a single convergence point. All convergence points lie on a straight line perpendicular to the projection screen, and the vertical distance from the convergence point to the projection screen varies continuously with the radius of the unit lenses. The projection screen of the present invention optimizes a more reasonable projection light convergence scheme and convergence position, effectively extending the viewing field of view, effectively improving viewing brightness and brightness uniformity across a wide viewing area, reducing restrictions on the viewer's position, and enhancing the viewing experience.

Description

Technical Field

[0001] The present invention relates to the field of projection display technology, and in particular to a projection screen and a method for fitting changes in convergence points of the projection screen. Background Art

[0002] A projection display system requires a projector and a projection screen. The projection screen's function is to image the image emitted by the projector and redistribute the projected light intensity. This redistribution relies on various microstructures on the screen to diffuse, converge, or control the light's transmission direction as needed to meet the needs of different viewing fields. One of the widespread problems with current projection screens is that the screen's displayed brightness varies significantly at different viewing positions. Unlike LCD or LED screens, which display consistent brightness across a wide field of view, one of the differences between projection screens and LCD or LED screens is the uneven brightness perceived by viewers across different viewing fields, significantly impacting their visual experience. Furthermore, in popular short-throw projection applications, the perceived field of view of the projection screen is also smaller than that of LCD or LED screens.

[0003] The general design method of the projection system is to use the microstructure on the projection screen to converge the projection light to the front of the geometric center of the projection screen. For example, the patent document with the domestic patent application publication number CN109917613A describes the use of the lens surface of the Fresnel lens to converge the projection light to a position 3 meters in front of the geometric center of the screen. Figure 1 As shown, the problem with this technical solution in actual application is that only the viewer located 3 meters in front of the geometric center of the screen sees the highest screen brightness, while the viewer at other positions can receive very little light and see a very low screen brightness. In addition, the screen brightness distribution seen at other positions is extremely uneven. The existing technology can only see a brighter image when the viewer's eye level is exactly at the height of the projection screen convergence point. For viewers with taller or shorter heights, since the viewer's eye level deviates from the projection screen convergence point and cannot receive more light, the brightness of the image seen is very low, resulting in a very small viewing field of the projection system. Summary of the Invention

[0004] The technical problem to be solved and the technical task proposed by the present invention are to improve the existing technology and provide a projection screen to solve the problem that the traditional projection screen in the current technology has a small field of view, high requirements on the viewer's position, and only a small area of ​​the optimal viewing range. If it deviates from the optimal viewing position, the viewing brightness will be extremely low and the screen brightness will be extremely uneven.

[0005] In order to solve the above technical problems, the technical solution of the present invention is:

[0006] A projection screen is provided with a microstructure layer for converging projection light. The microstructure layer includes a plurality of unit lenses with sawtooth-shaped cross sections arranged in concentric rings in the plane direction of the projection screen. Each unit lens converges the projection light to a convergence point. All convergence points are located on the same straight line perpendicular to the projection screen. The vertical distance from the convergence point to the projection screen varies continuously with the radius of the unit lens.

[0007] The projection screen described in the present invention has a variable convergence point of projection light, and the convergence point specifically changes with the radius of the unit lens. The microstructure layer is in the shape of an annular Fresnel lens, which can effectively converge the projection light. By designing the pitch, height and inclination angle of the unit lens, the convergence focus of each unit lens on the projection light can be controlled. Compared with the prior art in which the entire projection screen converges the projection light to a single convergence point, the present invention effectively broadens the area range of good viewing experience, so that the viewer can always receive sufficient projection light in a large viewing field, thereby ensuring viewing brightness. For example, when the viewer moves along the straight line where the convergence point is located and between the convergence point farthest from the projection screen and the convergence point closest to the projection screen, the viewer will always receive sufficient projection light in a certain area on the projection screen, thereby effectively improving the overall viewing brightness in a large viewing area. In the prior art, due to the convergence of the entire projection screen, the viewer can always receive sufficient projection light in a certain area on the projection screen, thereby effectively improving the overall viewing brightness in a large viewing area. The projection screen converges the projection light to a single convergence point. Once the viewer deviates from the convergence point, the viewing brightness of the entire screen will drop sharply, seriously affecting the viewing experience. In addition, the method of using a unit lens to change the convergence point of the projection light as the radius of the unit lens changes also effectively improves the uniformity of the screen viewed in a large viewing field. For example, the center of the image light projected by the projector is usually the brightest, that is, the light projected in the middle area of ​​the projection screen is the brightest. When the existing technology uses the entire projection screen to converge the projection light to a single convergence point, the entire picture viewed by the viewer when he is in the best viewing position will be brighter in the middle and darker at the edges, and the brightness uniformity is poor. In the present invention, the convergence point of the projection light by the unit lens changes as the radius of the unit lens, which can avoid excessive concentration of light and effectively improve the viewing brightness uniformity. The present invention greatly improves the effective viewing field range and improves the viewing experience.

[0008] Furthermore, the vertical distance from the convergence point to the projection screen increases as the radius of the unit lens increases;

[0009] Alternatively, the vertical distance from the convergence point to the projection screen decreases as the radius of the unit lens increases;

[0010] Alternatively, the vertical distance from the convergence point to the projection screen first increases and then decreases as the radius of the unit lens increases.

[0011] The design can be customized according to the size of the projection screen, the specific viewing scene, the viewer's usage habits, etc., thereby maximizing the viewing experience. The vertical distance from the convergence point to the projection screen first increases and then decreases as the radius of the unit lens increases, that is, the central area of ​​the projection screen converges the projection light to a place farther away from the projection screen, that is, the projection screen makes the projection light in the central area diverge farther away. This method can reduce the viewing brightness of the central area of ​​the projection screen when viewed at a closer distance, solves the problem of the middle of the projection screen being too bright and the edges being too dark, and improves the uniformity of viewing brightness. Moreover, since the projection light in the central imaging area converges to a place farther away from the projection screen, a high-brightness picture can be viewed when viewed from a distance, so that the overall brightness of the screen viewed from close range and from a distance will not differ too much, thereby improving the consistency of the viewing experience between close and long distances and improving the effective viewing field range.

[0012] Furthermore, the vertical distance from the convergence point formed by the unit lenses having a radius value of half the maximum radius of the unit lenses on the microstructure layer to the projection screen is the largest;

[0013] Alternatively, the vertical distance from the convergence point formed by the unit lenses passing through the geometric center point of the projection screen to the projection screen is the largest.

[0014] The viewing brightness of the middle area of ​​the projection screen is reduced when viewing at medium or close distances, solving the problem of the middle area of ​​the projection screen being too bright and the edges being too dark, and improving the viewing brightness uniformity.

[0015] Furthermore, the maximum vertical distance between the convergence point and the projection screen is less than or equal to 20 times the height of the projection screen. A vertical distance between the convergence point and the projection screen cannot be too large, as this will cause a sudden change in the shape of the microstructure layer, making it difficult to process. A too large vertical distance can also result in low brightness, which can lead to uneven viewing brightness.

[0016] Furthermore, all the convergence points are located on a straight line passing through the centers of the concentric circles of the unit lenses and perpendicular to the projection screen. The projection light can be fully converged to ensure the viewing brightness in the effective viewing field.

[0017] Furthermore, the centers of the concentric circles of the unit lenses are located outside the area of ​​the projection screen, and the microstructure layer is in the shape of an annular Fresnel lens with an offset structure. The centers of the concentric circles of the unit lenses are specifically located below the projection screen, and the centers of the concentric circles are on a straight line passing vertically through the geometric center of the projection screen. Since the centers of the concentric circles are located outside the area of ​​the projection screen, the unit lenses on the projection screen area are part of a perfect circle, that is, the unit lenses are arc-shaped. In other words, the entire microstructure layer includes a number of arc-shaped unit lenses arranged radially along the centers of the concentric circles.

[0018] Furthermore, the vertical distance from the convergence point to the projection screen is related to the radius of the unit lens in a curve. The vertical distance from the convergence point to the projection screen may first increase and then decrease as the radius of the unit lens increases, or the vertical distance from the convergence point to the projection screen may increase as the radius of the unit lens increases, but the slope of the increase is changing, which may be an increasing slope or a decreasing slope.

[0019] Furthermore, the relationship between the vertical distance from the convergence point to the projection screen and the radius of the unit lens is represented by a conic section, which includes a parabola, a circular arc, an elliptical arc, etc., and is mainly manifested in that the vertical distance from the convergence point to the projection screen first increases and then decreases as the radius of the unit lens increases. That is, when the radius of the unit lens is close to the middle value of its variation range, the vertical distance from the convergence point to the projection screen is larger. In other words, the central area of ​​the projection screen converges the projection light to a place farther away from the projection screen.

[0020] Furthermore, the relationship between the vertical distance from the convergence point to the projection screen and the radius of the unit lens satisfies the following relationship formula:

[0021]

[0022] Wherein, y is the vertical distance from the convergence point to the projection screen, in millimeters;

[0023] R is the radius of the unit lens, in millimeters;

[0024] G is the diagonal size of the projection screen, in inches;

[0025] a0~a n is a constant related to the values ​​of y, R and G, with the unit being millimeters, n≥2, n is an integer, a0~a n The constant is calculated by the following formula:

[0026]

[0027] Among them, R0~R n is the radius value of the selected n+1 unit lenses with different radii, y0~yn It is the vertical distance from the convergence point of each preset unit lens to the projection screen.

[0028] The vertical distance from the convergence point to the projection screen is a multi-order function of the unit lens radius. The vertical distance from the convergence point to the projection screen changes nonlinearly with the change of the unit lens radius, which can avoid excessive concentration of light, greatly improve the effective viewing field of view, and effectively improve the viewing brightness and brightness uniformity in a large viewing field, thereby improving the viewing experience.

[0029] The above-mentioned method for fitting the change of the convergence point of the projection screen is to select k unit lenses with different radii and set the vertical distance from the convergence point of each unit lens to the projection screen respectively, where k ≥ 3, and k is an integer;

[0030] Then, according to the constant calculation formula, we can get a0~a k-1 , thereby obtaining the relationship formula between the vertical distance from the convergence point to the projection screen and the k-1 order of the unit lens radius;

[0031] Among the selected unit lenses, a radius value of one unit lens is half of the maximum radius of the unit lenses on the microstructure layer, and a radius value of at least one unit lens is greater than half of the maximum radius of the unit lenses on the microstructure layer, and a radius value of at least one unit lens is less than half of the maximum radius of the unit lenses on the microstructure layer;

[0032] Alternatively, among the selected unit lenses, one unit lens passes through the geometric center point of the projection screen, and the radius value of at least one unit lens is greater than the radius value of the unit lens passing through the geometric center point of the projection screen, and the radius value of at least one unit lens is smaller than the radius value of the unit lens passing through the geometric center point of the projection screen.

[0033] The method is easy to implement and simple to calculate, and can accurately fit the changing relationship between the vertical distance from the convergence point of the projection light to the projection screen and the radius of the unit lens. Each unit lens in the microstructure layer is then specifically designed according to the fitted relationship formula, including designing the pitch, height and inclination angle of the unit lens to ensure that the convergence focus of the projection light of each unit lens meets the design requirements, that is, the vertical distance from the convergence focus of the projection light of each unit lens to the projection screen satisfies the relationship formula.

[0034] Furthermore, the vertical distance from the convergence point to the projection screen is linearly correlated with the unit lens radius or piecewise linearly correlated. The linear correlation means that the vertical distance from the convergence point to the projection screen increases or decreases linearly with the increase of the unit lens radius. The piecewise linear correlation means that the entire variation range of the unit lens radius is divided into multiple intervals, and in each interval, the vertical distance from the convergence point to the projection screen increases or decreases linearly with the increase of the unit lens radius.

[0035] Furthermore, when the vertical distance from the convergence point to the projection screen is linearly related to the radius of the unit lens, the following relationship formula is satisfied:

[0036]

[0037] Wherein, y is the vertical distance from the convergence point to the projection screen, in millimeters;

[0038] R is the radius of the unit lens, in millimeters;

[0039] G is the diagonal size of the projection screen, in inches;

[0040] a0 and a1 are constants related to the values ​​of y, R, and G, and are expressed in millimeters. a0 and a1 are calculated using the following constant calculation formula:

[0041]

[0042] Wherein, R0 and R1 are the radius values ​​of the selected unit lenses with different radii, and y0 and y1 are the preset vertical distances from the convergence point of each unit lens to the projection screen.

[0043] Furthermore, when the diagonal size G of the projection screen is ≤ 100 inches, a1>0, a0>0; when the diagonal size G of the projection screen is > 100 inches, a1<0, a0>0.

[0044] Furthermore, when the vertical distance from the convergence point to the projection screen is linearly correlated with the unit lens radius, the following relationship formula is satisfied:

[0045]

[0046] Wherein, y is the vertical distance from the convergence point to the projection screen, in millimeters;

[0047] R is the radius of the unit lens, in millimeters;

[0048] G is the diagonal size of the projection screen, in inches;

[0049] a0 and a1 are constants related to the values ​​of y, R, and G, and are expressed in millimeters. When the radius of the unit lens R≤b, a1>0, and when R>b, a1<0, where b is a preset value within the radius variation range of the unit lens on the microstructure layer;

[0050] a0 and a1 are obtained by the following constant calculation formula:

[0051]

[0052] Among them, R0 and R1 are the radius values ​​of unit lenses with different radii selected within the range of the radius of the unit lens R≤b, or R0 and R1 are the radius values ​​of unit lenses with different radii selected within the range of the radius of the unit lens R≥b, and y0 and y1 are the preset vertical distances from the convergence point of each unit lens to the projection screen.

[0053] The above-mentioned method for fitting the change of the convergence point of the projection screen is to select k unit lenses with different radii and set the vertical distance from the convergence point of each unit lens to the projection screen respectively, where k ≥ 3, and k is an integer;

[0054] Select two unit lenses and calculate a0 and a1 according to the constant calculation formula, then select two more unit lenses and calculate a0 and a1 according to the constant calculation formula, and so on to obtain multiple sets of a0 and a1, and calculate the average value as the final value, so as to obtain the relationship formula between the vertical distance from the convergence point to the projection screen and the radius of the unit lens;

[0055] Among the selected unit lenses, a radius value of one unit lens is half of the maximum radius of the unit lenses on the microstructure layer, and a radius value of at least one unit lens is greater than half of the maximum radius of the unit lenses on the microstructure layer, and a radius value of at least one unit lens is less than half of the maximum radius of the unit lenses on the microstructure layer;

[0056] Alternatively, among the selected unit lenses, one unit lens passes through the geometric center point of the projection screen, and the radius value of at least one unit lens is greater than the radius value of the unit lens passing through the geometric center point of the projection screen, and the radius value of at least one unit lens is smaller than the radius value of the unit lens passing through the geometric center point of the projection screen.

[0057] The method of obtaining the average values ​​of multiple groups of a0 and a1 can improve the fitting accuracy, so that the vertical distance from the convergence point to the projection screen can more accurately meet the design requirements as the radius of the unit lens changes.

[0058] Compared with the prior art, the present invention has the following advantages:

[0059] The projection screen described in the present invention optimizes a more reasonable projection light convergence scheme and convergence position, effectively improving the viewing field range, effectively improving the viewing brightness and brightness uniformity in a large viewing field in an area, reducing the restrictions on the viewer's position, and improving the viewing experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is a schematic diagram of a projection system in the prior art;

[0061] Figure 2 is a schematic diagram of a projection system of the present invention;

[0062] Figure 3 Schematic diagram of the relationship between the vertical distance from the convergence point of the projection screen to the projection screen and the radius of the unit lens of the present invention;

[0063] Figure 4 is a schematic diagram of an embodiment of a projection screen of the present invention;

[0064] Figure 5 is a schematic diagram of the cross-sectional structure of the projection screen of the present invention;

[0065] Figure 6 is another schematic cross-sectional structure diagram of the projection screen of the present invention;

[0066] Figure 7 is another schematic cross-sectional structure diagram of the projection screen of the present invention;

[0067] Figure 8 This is a comparison diagram of the optical paths of a projection system of the present invention and a projection system of the prior art;

[0068] Figure 9 Schematic diagram of the relationship between the vertical distance from the convergence point of the projection screen to the projection screen and the radius of the unit lens in Example 2;

[0069] Figure 10 This is a schematic diagram of an embodiment of a projection screen in the second embodiment.

[0070] In the picture:

[0071] 10-projection screen; 20-projection system; 101-substrate layer; 102-microstructure layer; 1021-unit lens; 103-reflective material layer; 104-diffusion layer; 105-coloring layer; 106-first substrate layer; 1041-light diffusion material; 1051-light absorption material; Z-straight line passing through the center of the concentric circles and perpendicular to the projection screen; O1-center of the concentric circles; L-vertical distance between the convergence point and the plane of the projection screen; O-geometric center; F-focus of the Fresnel lens; X-viewer; Y-projector. DETAILED DESCRIPTION

[0072] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0073] A projection screen disclosed in an embodiment of the present invention effectively improves the viewing field, reduces restrictions on the viewer's position, ensures good viewing brightness and screen brightness uniformity within a larger viewing area, and improves the viewing experience.

[0074] Example 1

[0075] like Figure 2 FIG. 1 is a schematic diagram of a projection system of the present invention, wherein the projection system includes a projector Y and a projection screen 10. The projection screen 10 is used to image the projection light emitted by the projector Y. When viewed from the normal direction of the projection screen 10, the projector is located outside the area of ​​the projection screen. Specifically, the projector Y is located below the front side of the projection screen 10. The projector Y is a short-focus projector that transmits image light obliquely upward onto the projection screen 10. The projection screen 10 includes a substrate layer 101 and a microstructure layer 102 for converging the projection light. The microstructure layer includes a plurality of unit lenses 1021 with a serrated cross-section and arranged in a concentric ring shape in the plane direction of the projection screen. Specifically, all the unit lenses 1021 have a common concentric circle center O1. , the unit lenses 1021 are arranged at intervals along the radial direction, and the concentric circle centers O1 of the unit lenses 1021 are located outside the area of ​​the projection screen 10, that is, the microstructure layer is in the shape of an annular Fresnel lens with an offset structure, and the concentric circle centers O1 of the unit lenses 1021 are specifically located below the projection screen 10, and the concentric circle centers O1 are located on a straight line passing through the geometric center O of the projection screen 10 in the vertical direction. Since the concentric circle centers O1 are located outside the area of ​​the projection screen, the unit lenses on the projection screen area are part of a perfect circle, that is, the unit lenses 1021 are arc lines. In other words, the entire microstructure layer includes a plurality of arc-shaped unit lenses 1021 arranged radially along the centers of the concentric circles, and each unit lens 1021 converges the projection light to a convergence point (such as Figure 2 The convergence points A, B, D, E, etc. in the figure, other convergence points are not shown in the figure), and these convergence points have a one-to-one corresponding vertical distance from the screen plane of the projection screen 10 (such as Figure 2L1, L2, L3, L4, etc. in the figure, other vertical distances are not shown), the vertical distance from the convergence point to the projection screen changes continuously with the radius of the unit lens (for example, from the center of the concentric ring unit lens to the outside, the radius of the unit lens is continuously increased, and each radius value corresponds to a vertical distance value, so the values ​​of these vertical distances also change continuously. For ease of understanding, we can regard these vertical distances as focal lengths defined in optical physics, that is, this design scheme designs a projection screen with continuously variable focal length). Specifically, the vertical distance from the convergence point to the projection screen is related to the radius of the unit lens as a curve.

[0076] All the convergence points are on the same straight line Z perpendicular to the projection screen, and the straight line Z passes through the center of the concentric circles of the unit lenses. Since the center O1 of the concentric circles of the unit lenses is located below the projection screen 10, the straight line Z is lower than the geometric center height of the projection screen. In other words, the convergence point of the projection light of the unit lens 1021 is lower than the geometric center height of the projection screen. The convergence point designed in this way can converge more projection light to the viewer area, so that the viewer feels that the brightness of the projection system is higher, more uniform, and the viewing field is larger.

[0077] As a further explanation, there are many possibilities for these vertical distances to change with the radius. They may increase with the increase of radius, or first increase and then decrease with the increase of radius, or decrease with the increase of radius. These vertical distances determine the position of light transmission. They need to be combined with the application scenario of the projection system to determine the specific values ​​of these vertical distances, and also to determine the relationship between the vertical distance from the convergence point to the projection screen and the radius of the unit lens.

[0078] Furthermore, if Figure 3 As shown in FIG. 1 , a schematic diagram of an embodiment of a coordinate system composed of the relationship between the vertical distance from the convergence point of the projection screen to the projection screen and the radius of the unit lens in the projection system of the present invention is shown. The relationship between the values ​​of these vertical distances and the radius R of the concentric ring unit lens can be represented by a continuous smooth curve. The smooth curve here means that there are no sudden turns on the curve, that is, there are tangents everywhere on the curve. Figure 3As shown in curves 1, 2, and 3, curve 1 describes that the relationship between these vertical distances L and the radius R is a parabola, curve 2 describes that the relationship between these vertical distances L and the radius R is a circular arc, and curve 3 describes that the relationship between these vertical distances L and the radius R is an elliptical arc. These curves belong to several types of conic sections (conic sections refer to curves of various shapes obtained by intercepting a conical figure from all directions with a plane), and they all have a common feature that is, they are high in the middle and low on both sides, that is, the closer the radius value is to half of the maximum radius of the unit lens on the microstructure layer, the greater the vertical distance between the convergence point of the projection light and the projection screen. It can also be expressed as, the central area of ​​the projection screen converges the projection light to a place farther away from the projection screen, that is, the projection light in the central imaging area is diverged farther away. This method can reduce the viewing brightness of the central area of ​​the projection screen when viewed at a relatively close distance, solving the problem of the middle of the projection screen being too bright and the edge being too dark.

[0079] The relationship between the vertical distance from the convergence point to the projection screen and the radius of the unit lens satisfies the following relationship formula:

[0080]

[0081] Wherein, y is the vertical distance from the convergence point to the projection screen, in millimeters;

[0082] R is the radius of the unit lens, in millimeters;

[0083] G is the diagonal size of the projection screen, in inches;

[0084] a0~a n is a constant related to the values ​​of y, R and G, with the unit being millimeters, n≥2, n is an integer, a0~a n The constant is calculated by the following formula:

[0085]

[0086] Among them, R0~R n is the radius value of the selected n+1 unit lenses with different radii, y0~y n is the vertical distance from the convergence point of each unit lens to the projection screen. In other words, the a0 to a n The vertical distance from the convergence point of several unit lenses with different radii to the projection screen is calculated and obtained.

[0087] The relationship between the vertical distance from the convergence point to the projection screen and the unit lens radius is obtained by fitting using the following method:

[0088] Three unit lenses with different radii are selected, and each unit lens corresponds to a different area position of the projection screen;

[0089] Set the vertical distances from the convergence point of the projection light of the three selected unit lenses to the projection screen respectively;

[0090] The vertical distances between these convergence points and the projection screen plane are used as the vertical axis of the plane coordinate system, and the radius values ​​of the concentric ring unit lenses corresponding to these convergence points are used as the horizontal axis of the plane coordinate system. A polynomial fitting is used to obtain a relationship curve between the vertical distance from the convergence point to the projection screen and the radius of the unit lens.

[0091] Furthermore, if Figure 4 As shown in the center front view, among the selected unit lenses, the radius of one unit lens is half of the maximum radius of the unit lens on the microstructure layer, as shown by point ②, and the radius of at least one unit lens is greater than half of the maximum radius of the unit lens on the microstructure layer, as shown by point ①. At least one unit lens has a radius less than half of the maximum radius of the unit lens on the microstructure layer, as shown by point ③. Points should be taken on both sides of point ②, not just on one side. In this way, the projection screen designed after fitting can better meet the requirements of actual use.

[0092] Alternatively, among the selected unit lenses, one unit lens passes through the projection screen's geometric center point O, and at least one unit lens has a larger radius than the unit lens passing through the projection screen's geometric center point, as shown by point ①. At least one unit lens has a smaller radius than the unit lens passing through the projection screen's geometric center point, as shown by point ③. Because the distance from the center point of the concentric circles of the unit lenses to the lower edge of the projection screen is very close, only a little over 100 microns, the deviation between the two points is small, whether selecting point ② or the projection screen's geometric center point. Both methods can accurately fit the desired projection screen's structural parameters, so both methods are acceptable.

[0093] Specifically, assume that the unit lens with the largest radius on the projection screen converges the projection light at 3600mm, that is, y3 = 3600; assume that the concentric ring unit lens with the smallest radius on the projection screen converges the projection light at 4000mm, that is, y1 = 4000mm; assume that the unit lens with a radius of half the maximum radius of the unit lens on the projection screen converges the projection light at 4800mm, that is, y2 = 4800mm; the diagonal size G of the projection screen is variable, unit: inches, the screen aspect ratio is 16:9, the length is represented by the letter W, and the width is represented by the letter H (the width is also the height of the projection screen). Assume that the distance d from the center point O1 of the concentric circle of the unit lens to the bottom edge of the projection screen is d = d0*G / 100; d0 is the d value when the projection screen is 100 inches, and the following calculation formula can be obtained:

[0094]

[0095]

[0096]

[0097] This yields three design points: (R1, y1), (R2, y2), and (R3, y3). As can be seen from the above formula, the horizontal coordinates are all related to the diagonal dimension G of the projection screen. It is desirable to avoid discrepancies caused by different G values ​​during design. Considering that the d value in practice varies linearly with G, the three R values ​​are all linear functions of G. Fitting the three points in the coordinate system using a polynomial fit yields the following fitting curve:

[0098] Since y1, y2, and y3 are known in the three design points (R1, y1), (R2, y2), and (R3, y3), the diagonal size G of the projection screen is also a constant, and the radius R is also known, substituting the known values ​​into the above formula yields:

[0099] a2=-15.16133694;

[0100] a1=268.356148;

[0101] a0=3631.578786.

[0102] From the above fitting results, we can see that for various sizes of 16:9 projection screens, starting from the minimum radius of the unit lens in the projection screen, as the radius R increases, the vertical distance of the convergence point gradually increases in a parabolic trend. When it reaches half of the maximum radius of the unit lens on the projection screen, the vertical distance from the convergence point to the projection screen plane increases to 4800mm and reaches the parabola vertex. After that, the vertical distance from the convergence point to the projection screen plane gradually decreases as R increases. When it reaches the maximum radius of the unit lens on the projection screen (that is, the position of the upper left and right corners of the projection screen), the vertical distance from the convergence point to the projection screen drops to 3600mm. Figure 4 As shown, the vertical distance L5 between the convergence point N of the projection light and the projection screen plane of the unit lens with a radius of half the maximum radius or the unit lens passing through the geometric center O of the projection screen is greater than the vertical distances L6 and L7 between the other convergence points M and V and the projection screen plane. The purpose of this design is to make the area at the center of the projection screen converge the projection light to a farther position, thereby reducing the intensity of the projection light in the center area of ​​the projection screen felt by the viewer, while other areas on the projection screen converge more projection light to the viewer's position, thereby increasing the intensity of the projection light felt by the viewer, so as to achieve the purpose of improving the display brightness uniformity of the projection screen.

[0103] Furthermore, based on different design values ​​y1, y2, and y3, as well as d0 and the diagonal size G of a 100-inch projection screen, a second-order polynomial fitting curve can be obtained for the vertical distance from the convergence point to the projection screen of any size as a function of the unit lens radius. This can then yield the relationship between the convergence point y and R: y = f(R / G). The advantage of this formula is that for the same design, the curve of the vertical distance from the convergence point to the projection screen and the unit lens radius remains fixed for projection screens of different sizes, meaning their effective viewing fields remain consistent.

[0104] The above specific fitting method adopts the method of selecting three unit lenses with different radii to obtain a second-order polynomial fitting curve. More points can be selected during fitting, that is, four, five or even more unit lenses with different radii are selected and the vertical distance from the convergence point of each unit lens to the projection screen is set respectively. In this way, it is only necessary to increase the order of the polynomial fitting to obtain k coefficients (i.e., a0~a k-1 ), and then a k-1 order polynomial fitting curve is obtained to represent the relationship between the vertical distance from the convergence point to the projection screen and the radius of the unit lens.

[0105] As a further explanation, Figure 4As shown in the middle left view, the maximum vertical distance from the convergence point to the projection screen is less than or equal to 20 times the height of the projection screen. Specifically, the vertical distance from the convergence point N of the projection light to the projection screen plane of the unit lens with a radius value of half the maximum radius or the unit lens passing through the geometric center O of the projection screen is less than or equal to 20 times the height of the projection screen. This is because in the design, the projection light in the central area of ​​the projection screen needs to be converged to a slightly farther position, which helps to reduce the brightness of the central area of ​​the projection screen perceived by the viewer and solve the problem of uneven display brightness caused by the excessive brightness of the central area of ​​the projection screen. However, the convergence of light in the central area of ​​the projection screen cannot be designed too far, otherwise the brightness of the central area of ​​the projection screen perceived by the viewer will be too low, resulting in the problem of low display brightness of the projection screen. Therefore, through actual design and use, it is found that the vertical distance from the convergence point N of the projection light to the projection screen plane of the unit lens with a radius value of half the maximum radius or the unit lens passing through the geometric center O of the projection screen is less than or equal to 20 times the height of the projection screen, which is the best for obtaining brightness and brightness uniformity.

[0106] As an alternative, Figure 5 As shown in FIG, it is a schematic diagram of the cross-sectional structure of a projection screen. Figure 5 As shown in Figure e, a diffusion layer 104 and a coloring layer 105 are further included between the substrate layer 101 and the microstructure layer 102. The diffusion layer 104 and the coloring layer 105 are separated into two independent layers, and the arrangement positions of the two layers can be exchanged. The other side of the substrate layer 101 is set to a rough surface, and the rough surface is formed by roughening the surface of the substrate. The rough surface can be formed by sandblasting or roughening the mold surface, and then transferred with glue or sprayed with glue containing diffusion particles. The rough surface can further diffuse the light, and play the role of uniform light, hardening protection and imaging. The microstructure layer 102 includes a plurality of serrated unit lenses 1021, and a reflective material layer 103 is arranged on the unit lens 1021. The projection light emitted by the projector Y passes through the substrate layer 101 and the microstructure layer 102, and is finally reflected by the reflective material layer 103 on the microstructure layer, and then passes through the microstructure layer 102 and the substrate layer 101 to be emitted into the viewing range; as shown Figure 5 As shown in Figure g, a diffusion layer 104 and a coloring layer 105 are further provided between the substrate layer 101 and the microstructure layer 102. The diffusion layer 104 and the coloring layer 105 are fused into one layer. The other side of the substrate layer 101 is set as a rough surface. The reflective microstructure layer 102 includes a plurality of serrated unit lenses 1021, and a reflective material layer 103 is provided on the unit lenses 1021.

[0107] Furthermore, the rough surface can also be fabricated with microstructures that increase the diffusion angle of the projection screen, making the horizontal diffusion angle larger than the vertical diffusion angle. Alternatively, the microstructures can be used to increase the diffusion capacity of overly bright areas of the projection screen, thereby reducing the brightness of these overly bright areas and improving the brightness uniformity of the projection screen.

[0108] Furthermore, the other side of the substrate layer 101 can also be smooth, and an anti-reflection material is provided on the smooth surface, such as an anti-reflection film composed of high and low refractive index materials, which is used to reduce the reflection loss of obliquely incident projection light and enhance the display brightness of the projection screen.

[0109] As a further explanation, the substrate layer 101 can be made of materials including but not limited to the following, such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, casein phosphopeptide, biaxially oriented polypropylene, polycarbonate, polyethylene terephthalate, polyamide, polyurethane, polymethyl methacrylate, polycarbonate, thermoplastic polyurethane elastomer and other flexible plastic or rubber materials, or glass, acrylic, ceramic and other transparent substrates with certain rigidity.

[0110] To further explain, diffusion layer 104 is provided with diffusion particles and resin material. These diffusion particles can evenly scatter light passing through diffusion layer 104, resulting in a more uniform light intensity distribution. The diffusion particles include, but are not limited to, silica particles, alumina particles, titanium oxide particles, cerium oxide particles, zirconium oxide particles, tantalum oxide particles, zinc oxide particles, and magnesium fluoride particles, and their particle sizes are preferably between 5 nm and 200 nm. It should be noted that when diffusion particles are provided within diffusion layer 104, they can be evenly distributed or unevenly distributed within diffusion layer 104. For optimal results, a uniform distribution of the diffusion particles within diffusion layer 104 is preferred.

[0111] Furthermore, the diffusion layer 104 may be configured as a single layer or multiple layers of arcuate cylindrical microlenses to diffuse light through the arcuate surfaces of the arcuate cylindrical microlenses, thereby increasing the viewing field of the projection screen and improving display brightness uniformity.

[0112] Furthermore, a light-absorbing material and a resin material are provided within the coloring layer 105. The light-absorbing material can absorb some unwanted light (such as ambient light) and selectively transmit the desired light. The light-absorbing material includes, but is not limited to, various pigments, dyes, carbon black, black iron oxide, etc., and plays a role in filtering and coloring.

[0113] Furthermore, the reflective material layer 103 has either a specular reflective function or a diffuse reflective function, that is, the reflective material layer 103 can be a specular reflective layer or a diffuse reflective layer. Both specular and diffuse reflective layers can reflect light, but the difference is that the specular reflective layer has a smooth surface like a mirror, and the reflected light and the incident light satisfy the optical reflection theorem, forming a clear image. It can generally be produced by electroplating. The diffuse reflective layer has a slightly rough surface, and the reflected light is transmitted in all directions without a regular pattern, which does not form a clear image. It is generally produced by printing or spray plating.

[0114] As a further supplementary explanation, the reflective material layer 103 can be set to have a certain light transmittance, so that the ambient light entering the interior of the projection screen can pass through the reflective layer, thereby preventing the ambient light from being reflected into the viewing area, which has a good effect on improving the contrast of the projection screen.

[0115] Furthermore, pigments / dyes that can reflect red, green, and blue light and absorb / transmit other colors of visible light can be added to the reflective material layer 103 to absorb more ambient light and improve the contrast of the projection screen.

[0116] Furthermore, the reflective material layer may not be provided on the unit lenses of the projection screen, so that the projection screen can be applied to a rear projection system scenario, with the projector and the viewer being located on either side of the projection screen respectively.

[0117] Furthermore, the surface of the substrate layer can be smooth to achieve ultra-high-definition images. It can also be provided with microstructures with a larger horizontal diffusion angle than a vertical diffusion angle, thereby increasing the horizontal viewing angle of the projection screen and providing a wider horizontal viewing field. Alternatively, the substrate layer can be provided with microstructures with anisotropic diffusion angles, meaning that the microstructures have different light diffusion capabilities in different directions. Based on the brightness differences at different locations on the projection screen, the microstructures can have larger diffusion angles at high-brightness locations to reduce brightness, while smaller diffusion angles at low-brightness locations ensure that brightness remains unchanged. This results in more uniform display brightness on the projection screen and a wider viewing field.

[0118] As an alternative, Figure 6 As shown in FIG, it is a schematic diagram of the cross-sectional structure of an optical projection screen. Figure 6 As shown in Figure e, the other side of the substrate layer 101 is provided with a first substrate layer 106, a diffusion layer 104, and a coloring layer 105 in sequence. The diffusion layer 104 and the coloring layer 105 are separated into two independent layers, and the positions of the two layers can be interchanged. The outer surface of the first substrate layer 106 is provided as a rough surface. The microstructure layer 102 includes a plurality of sawtooth-shaped unit lenses 1021, and a reflective material layer 103 is provided on the unit lenses 1021. Figure 6As shown in Figure g, the other side of the substrate layer 101 is provided with a first substrate layer 106, a diffusion layer 104 and a coloring layer 105 in sequence. The diffusion layer 104 and the coloring layer 105 are fused into one layer. The outer surface of the first substrate layer 106 is set to a rough surface. The microstructure layer 102 includes a plurality of serrated unit lenses 1021, and a reflective material layer 103 is provided on the unit lenses 1021.

[0119] As an alternative, Figure 7 Figure 1 shows a schematic cross-sectional structure of an optical projection screen. Light diffusing material 1041 and light absorbing material 1051 are disposed within substrate layer 101. Light diffusing material 1041 contains diffusing particles. The presence of the light diffusing material within substrate layer 101 further enhances the scattering angle of light within the screen, resulting in a more uniform display of screen brightness. Light absorbing material 1051 contains light-absorbing material, which filters and adjusts the color of the light.

[0120] Furthermore, if Figure 8 The optical path comparison diagram of the projection system of the present invention and the projection system of the prior art is shown in FIG. Figure 8 Indicated by dotted lines, Figure 8 The solid line in the middle represents the optical path of the projection system of the present invention. Figure 8 As can be seen from the light path indicated by the dashed line, the lens design in conventional projection screens is to converge the light emitted by the projector to a position F 3 meters in front of the geometric center O of the screen. That is, the focus F of the Fresnel lens is 3 meters away from the lens structure on the screen. In practice, the viewer X is also located 3 meters in front of the screen. Therefore, the viewer at the focal position receives the most light and is therefore considered to see the brightest screen. However, this design does not take into account the differences in heights of viewers, the needs of multiple viewers watching side by side, and the different sizes of projection screens. When the viewer's height deviates from the focal position (in most cases, when the viewer is sitting and watching, the line of sight of the eyes is lower than the geometric center of the screen), the viewer can only receive very little light, so the image on the screen cannot be seen clearly. In practice, it is difficult to find viewers whose height just matches this design. Therefore, the design of the existing technology is very unsuitable and cannot solve the problem of uneven screen brightness. Moreover, when the light all converges to the focal position (the convergence area is very small) and there are multiple viewers watching side by side, only the viewer at the focal position can receive the light, and the other viewers can only receive very little light. Therefore, the screen brightness felt by other viewers will also be very low and uneven. Therefore, the design of the existing technology is also not suitable.

[0121] Furthermore, the technical solution of the present invention solves the above-mentioned problems of the prior art, such as Figure 8The solid line in the middle indicates that when a typical viewer X sits and watches a projection screen, their line of sight is typically below the screen's geometric center. Therefore, the present invention employs a novel unit lens design that converges light onto a specific area directly in front of the center C of the concentric ring-shaped unit lenses. This allows a large area to receive a significant amount of projection light when the viewer is 3 meters in front of the screen. Therefore, regardless of the viewer's height or height, or the number of viewers present, viewers within this area experience high screen brightness and a higher perceived brightness uniformity. Furthermore, to ensure viewing comfort for the human eye, the larger the projection screen, the greater the viewing distance. Therefore, the convergence point area must be adjusted based on the size of the projection screen to ensure optimal viewing brightness for viewers at different locations. This requires the present invention's design of a continuously variable convergence point to meet these requirements. Therefore, the present invention's projection screen technology improves screen brightness and display brightness uniformity, making it more suitable for viewing.

[0122] Furthermore, the materials of the unit lens of the present invention include but are not limited to radiation-curing resins, thermosetting resins, and reactive curing resins. The method of making a unit lens using the above raw materials is to use a roller mold made with the unit lens to transfer and coat the raw materials onto a base material.

[0123] Furthermore, the projection screen of the present invention also includes a black backboard, a decorative frame and a pendant. The black backboard is arranged on the side of the reflective material layer away from the microstructure layer, the decorative frame is wrapped around the optical projection screen, and the pendant is arranged on the side of the black backboard away from the microstructure layer.

[0124] Furthermore, the black backboard can be tightly bonded to the reflective material layer by double-sided tape or EVA hot melt adhesive, and black paint can be provided on the surface of the black backboard to absorb unnecessary light incident on the black backboard, which can appropriately improve the contrast of the projection screen.

[0125] Furthermore, a decorative frame is mounted around the black back panel, surrounding the various layers of the projection screen in the thickness direction, thereby securing and enhancing the projection screen's appearance and dividing the projection display area. The decorative frame and the black back panel can be secured using double-sided tape or screws / bolts.

[0126] Furthermore, the pendant is fixed to the corresponding position of the black backboard by double-sided adhesive or screws, so as to facilitate the subsequent installation of the projection screen on the wall.

[0127] As a further supplementary explanation, the hanging piece may also be replaced with a magnetic material so that the projection screen can be mounted on the wall by magnetic adsorption to ensure the aesthetics of the wall.

[0128] Example 2

[0129] like Figure 9 As shown in FIG. 1 , a schematic diagram of an embodiment of a coordinate system composed of the relationship between the vertical distance from the convergence point of the projection screen to the projection screen and the radius of the unit lens in the projection system of the present invention is shown. The values ​​of these vertical distances are linearly correlated or piecewise linearly correlated with the radius R of the concentric ring unit lens. Figure 9 As shown by lines 1, 2, and 3 in the figure, straight line 1 describes that the relationship between these vertical distances L and the radius R is a straight line that points upward, that is, the vertical distance from the convergence point to the projection screen increases linearly with the increase of the unit lens radius; straight line 2 describes that the relationship between these vertical distances L and the radius R is a straight line that points downward, that is, the vertical distance from the convergence point to the projection screen decreases linearly with the increase of the radius; broken line 3 describes that the relationship between these vertical distances L and the radius R is a broken line that points upward at first and then downward at second, that is, the vertical distance from the convergence point to the projection screen increases linearly at first and then decreases linearly with the increase of the unit lens radius.

[0130] for Figure 9 For lines 1 and 2 in FIG, the relationship between the vertical distance from the convergence point to the projection screen and the radius of the unit lens satisfies the following relationship formula:

[0131]

[0132] Wherein, y is the vertical distance from the convergence point to the projection screen, in millimeters;

[0133] R is the radius of the unit lens, in millimeters;

[0134] G is the diagonal size of the projection screen, in inches;

[0135] a0 and a1 are constants related to the values ​​of y, R, and G, and are expressed in millimeters. a0 and a1 are calculated using the following constant calculation formula:

[0136]

[0137] Wherein, R0 and R1 are the radius values ​​of any two selected unit lenses with different radii, and y0 and y1 are the preset vertical distances from the convergence point of each unit lens to the projection screen.

[0138] Furthermore, as an embodiment, when the diagonal size G of the projection screen is less than or equal to 100 inches, a1>0, a0>0; when the diagonal size G of the projection screen is greater than 100 inches, a1<0, a0>0; this embodiment states that when the projection screen size is less than or equal to 100 inches, the optimal design method is that the vertical distance from the convergence point to the projection screen increases linearly with the increase of the unit lens radius; and when the projection screen size is greater than 100 inches, the optimal design method is that the vertical distance from the convergence point to the projection screen decreases linearly with the increase of the unit lens radius.

[0139] The relationship between the vertical distance from the convergence point to the projection screen and the unit lens radius is obtained by fitting using the following method:

[0140] Select at least three unit lenses with different radii, each unit lens corresponding to a different area position of the projection screen;

[0141] respectively setting the vertical distance from the convergence point of the projection light of the selected unit lens to the projection screen;

[0142] The vertical distances between these convergence points and the projection screen plane are taken as the vertical axis of the plane coordinate system, and the radius values ​​of the concentric ring unit lenses corresponding to these convergence points are taken as the horizontal axis of the plane coordinate system. Through linear fitting, a straight line is obtained to obtain the relationship between the vertical distance from the convergence point to the projection screen and the radius of the unit lens.

[0143] Furthermore, if Figure 4 As shown in the center front view, among the selected unit lenses, the radius of one unit lens is half of the maximum radius of the unit lens on the microstructure layer, as shown by point ②, and the radius of at least one unit lens is greater than half of the maximum radius of the unit lens on the microstructure layer, as shown by point ①. At least one unit lens has a radius less than half of the maximum radius of the unit lens on the microstructure layer, as shown by point ③. Points should be taken on both sides of point ②, not just on one side. In this way, the projection screen designed after fitting can better meet the requirements of actual use.

[0144] Alternatively, among the selected unit lenses, one unit lens passes through the projection screen's geometric center point O, and at least one unit lens has a larger radius than the unit lens passing through the projection screen's geometric center point, as shown by point ①. At least one unit lens has a smaller radius than the unit lens passing through the projection screen's geometric center point, as shown by point ③. Because the distance from the center point of the concentric circles of the unit lenses to the lower edge of the projection screen is very close, only a little over 100 microns, the deviation between the two points is small, whether selecting point ② or the projection screen's geometric center point. Both methods can accurately fit the desired projection screen's structural parameters, so both methods are acceptable.

[0145] Specifically, assume that the unit lens with the largest radius on the projection screen converges the projection light at 4800mm, that is, y3 = 4800mm; assume that the unit lens with the smallest radius on the projection screen converges the projection light at 3600mm, that is, y1 = 3600mm; assume that the unit lens with a radius of half the maximum radius of the unit lens on the projection screen converges the projection light at 4000mm, that is, y2 = 4000mm; the diagonal size G of the projection screen is variable, unit: inches, the screen aspect ratio is 16:9, the length is represented by the letter W, and the width is represented by the letter H (the width is also the height of the projection screen). Assume that the distance d from the center point O1 of the concentric circle of the unit lens to the bottom edge of the projection screen is d = d0*G / 100; d0 is the d value when the projection screen is 100 inches, and the following calculation formula can be obtained:

[0146]

[0147]

[0148]

[0149] This yields three design points: (R1, y1), (R2, y2), and (R3, y3). As can be seen from the above formula, the horizontal coordinates are all related to the diagonal dimension G of the projection screen. It is desirable to avoid discrepancies caused by different G values ​​during design. Considering that the d value in practice varies linearly with G, the three R values ​​are all linear functions of G. Fitting the three points in the coordinate system, using linear fitting, yields the following fitted line:

[0150] Since y1, y2, and y3 are known in the three design points (R1, y1), (R2, y2), and (R3, y3), the diagonal size G of the projection screen is also a constant, and the radius R is also known, the known values ​​can be substituted into the above formula to obtain a0 and a1. Since y and R are in a first-order linear relationship, in fact, only the data of two design points are needed to obtain a0 and a1. Therefore, any two of the three selected unit lenses can be used to obtain a0 and a1 through the constant calculation formula. Then, two more unit lenses are selected and a0 and a1 are obtained according to the constant calculation formula. This can be deduced to obtain multiple groups of a0 and a1, and the average value is taken as the final value. The final value is used to obtain the relationship formula between the vertical distance from the convergence point to the projection screen and the radius of the unit lens. The final a0 and a1 are as follows:

[0151] a1=128.43;

[0152] a0=3807.3.

[0153] From the above fitting results, we can see that for 16:9 projection screens of various sizes, starting from the minimum radius of the unit lens on the projection screen, the vertical distance from the convergence point to the projection screen increases linearly with the increase of radius R. When the unit lens radius on the projection screen reaches the maximum value, the vertical distance from the convergence point to the projection screen increases to 4800mm, reaching the highest point of the linear relationship. Figure 10 As shown, this design scheme aims to converge the projection light in the upper-middle area of ​​the projection screen toward the viewer, thereby increasing the intensity of the projection light perceived by the viewer, while the lower-middle area of ​​the projection screen converges more projection light toward a position away from the viewer, reducing the intensity of the projection light perceived by the viewer in the lower-middle area of ​​the projection screen, thereby achieving the goal of improving the uniformity of the projection screen's display brightness. This design scheme is suitable for projection screens 100 inches or less. The smaller the projection screen size, the closer the viewer is to the projection screen. In this case, since the lower-middle area of ​​the projection screen receives strong light intensity, it is necessary to converge the light toward a position away from the viewer, so that the viewer receives less light from the lower-middle area of ​​the projection screen. Since the upper area of ​​the projection screen receives less light intensity, it is necessary to converge more light toward the viewer, so that the viewer receives more light from the upper-middle area of ​​the projection screen, thereby achieving the goal of improving the uniformity of the viewing brightness. Therefore, this design scheme is suitable for small-sized projection screen designs.

[0154] When the projection screen size is greater than 100 inches, the larger the projection screen size is and the farther the viewer is from the projection screen, the light in the middle and lower areas of the projection screen converges to a place farther away from the projection screen, while the light in the middle and upper areas of the projection screen converges to a place closer to the projection screen. That is, the vertical distance from the convergence point to the projection screen decreases linearly with the increase of the unit lens radius, thereby improving the viewing brightness uniformity.

[0155] for Figure 9 Line 3 in the figure, the relationship between the vertical distance from the convergence point to the projection screen and the radius of the unit lens satisfies the following relationship formula:

[0156]

[0157] Wherein, y is the vertical distance from the convergence point to the projection screen, in millimeters;

[0158] R is the radius of the unit lens, in millimeters;

[0159] G is the diagonal size of the projection screen, in inches;

[0160] a0 and a1 are constants related to the values ​​of y, R, and G, and are expressed in millimeters. When the radius of the unit lens R ≤ b, a1 > 0, and when R > b, a1 < 0. b is a preset value within the radius variation range of the unit lens on the microstructure layer. Preferably, b is half of the maximum radius of the unit lens on the microstructure layer, or b is the radius value of the unit lens passing through the geometric center point of the projection screen. a0 and a1 are calculated using the following constant calculation formula:

[0161]

[0162] Among them, R0 and R1 are the radius values ​​of unit lenses with different radii selected within the range of the radius of the unit lens R≤b, or R0 and R1 are the radius values ​​of unit lenses with different radii selected within the range of the radius of the unit lens R≥b, and y0 and y1 are the preset vertical distances from the convergence point of each unit lens to the projection screen.

[0163] The relationship between the vertical distance from the convergence point to the projection screen and the unit lens radius is obtained by fitting using the following method:

[0164] Unit lenses with different radii are selected within the range of a unit lens radius R ≤ b, and unit lenses with different radii are selected within the range of a unit lens radius R ≥ b. Each unit lens corresponds to a different area position of the projection screen. At least three unit lenses with different radii are selected in total. One of the unit lenses must have a radius of b, that is, a unit lens with a radius value of half the maximum radius of the unit lenses on the microstructure layer or a unit lens passing through the geometric center point of the projection screen. The other unit lenses must include at least one unit lens with a radius less than b and at least one unit lens with a radius greater than b.

[0165] respectively setting the vertical distance from the convergence point of the projection light of the selected unit lens to the projection screen;

[0166] The vertical distances between these convergence points and the projection screen plane are taken as the vertical axis of the plane coordinate system, and the radius values ​​of the concentric ring unit lenses corresponding to these convergence points are taken as the horizontal axis of the plane coordinate system. Linear fitting is used to obtain the relationship line between the vertical distance from the convergence point to the projection screen and the radius of the unit lens.

[0167] Specifically, it is assumed that the unit lens with the largest radius on the projection screen converges the projection light at 4000 mm, that is, y3 = 4000 mm; it is assumed that the unit lens with the smallest radius on the projection screen converges the projection light at 3600 mm, that is, y1 = 3600 mm; it is assumed that the unit lens with a radius value of half the maximum radius of the unit lens on the projection screen converges the projection light at 4800 mm, that is, y2 = 4800 mm; thus, three design points (R1, y1), (R2, y2), and (R3, y3) are obtained. When the radius R of the unit lens is less than or equal to b, a0 and a1 can be obtained through (R2, y2) and (R3, y3) when the radius R of the unit lens is greater than or equal to b, thereby finally obtaining the relationship formula between the vertical distance from the convergence point to the projection screen and the radius of the unit lens;

[0168] When more unit lenses are selected, two of them are selected and a0 and a1 are calculated according to the constant calculation formula. Then, two more unit lenses are selected and a0 and a1 are calculated according to the constant calculation formula. This process is repeated to obtain multiple sets of a0 and a1. The average value is taken as the final value, and the relationship formula between the vertical distance from the convergence point to the projection screen and the radius of the unit lens is obtained from the final value.

[0169] The purpose of this design is to make the center area of ​​the projection screen converge the projection light to a farther position, thereby reducing the intensity of the projection light in the center area of ​​the projection screen felt by the viewer, while other areas on the projection screen converge the projection light more to the viewer's position, thereby increasing the intensity of the projection light felt by the viewer, so as to achieve the purpose of improving the display brightness uniformity of the projection screen.

[0170] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A projection screen, characterized in that: The projection screen is provided with a microstructure layer for converging projection light. The microstructure layer includes a plurality of unit lenses with sawtooth cross-sections arranged in a concentric ring shape in the plane direction of the projection screen. Each unit lens converges the projection light to a convergence point. All convergence points are located on the same straight line perpendicular to the projection screen. The vertical distance from the convergence point to the projection screen varies continuously with the radius of the unit lens. The vertical distance from the convergence point to the projection screen increases as the radius of the unit lens increases; Alternatively, the vertical distance from the convergence point to the projection screen decreases as the radius of the unit lens increases; Alternatively, the vertical distance from the convergence point to the projection screen first increases and then decreases as the radius of the unit lens increases; The vertical distance from the convergence point to the projection screen is related to the radius of the unit lens in a curve; The relationship between the vertical distance from the convergence point to the projection screen and the radius of the unit lens satisfies the following relationship formula: Wherein, y is the vertical distance from the convergence point to the projection screen, in millimeters; R is the radius of the unit lens, in millimeters; G is the diagonal size of the projection screen, in inches; a0~a n is a constant related to the values ​​of y, R and G, with the unit being millimeters, n≥2, n is an integer, a0~a n The constant is calculated by the following formula: Among them, R0~R n is the radius value of the selected n+1 unit lenses with different radii, y0~y n It is the vertical distance from the convergence point of each preset unit lens to the projection screen.

2. The projection screen according to claim 1, wherein The vertical distance from the convergence point formed by the unit lenses having a radius value of half the maximum radius of the unit lenses on the microstructure layer to the projection screen is the largest; Alternatively, the vertical distance from the convergence point formed by the unit lenses passing through the geometric center point of the projection screen to the projection screen is the largest.

3. The projection screen according to claim 2, characterized in that The maximum vertical distance from the convergence point to the projection screen is less than or equal to 20 times the height of the projection screen.

4. The projection screen according to claim 1, wherein All the convergence points are on a straight line passing through the centers of the concentric circles of the unit lenses and perpendicular to the projection screen.

5. The projection screen according to claim 1, wherein: The centers of the concentric circles of the unit lenses are located outside the area of ​​the projection screen.

6. The projection screen according to claim 1, wherein: The relationship between the vertical distance from the convergence point to the projection screen and the radius of the unit lens is represented by a conic curve.

7. A method for fitting the change of the convergence point of the projection screen according to claim 1, characterized in that: Select k unit lenses with different radii and set the vertical distance from the convergence point of each unit lens to the projection screen, k ≥ 3, where k is an integer; Then, according to the constant calculation formula, we can get a0~a k-1 , thereby obtaining the relationship formula between the vertical distance from the convergence point to the projection screen and the k-1 order of the unit lens radius; Among the selected unit lenses, a radius value of one unit lens is half of the maximum radius of the unit lenses on the microstructure layer, and a radius value of at least one unit lens is greater than half of the maximum radius of the unit lenses on the microstructure layer, and a radius value of at least one unit lens is less than half of the maximum radius of the unit lenses on the microstructure layer; Alternatively, among the selected unit lenses, one unit lens passes through the geometric center point of the projection screen, and the radius value of at least one unit lens is greater than the radius value of the unit lens passing through the geometric center point of the projection screen, and the radius value of at least one unit lens is smaller than the radius value of the unit lens passing through the geometric center point of the projection screen.

8. A projection screen, characterized in that: The projection screen is provided with a microstructure layer for converging projection light. The microstructure layer includes a plurality of unit lenses with sawtooth cross-sections arranged in a concentric ring shape in the plane direction of the projection screen. Each unit lens converges the projection light to a convergence point. All convergence points are located on the same straight line perpendicular to the projection screen. The vertical distance from the convergence point to the projection screen varies continuously with the radius of the unit lens. The vertical distance from the convergence point to the projection screen increases as the radius of the unit lens increases; Alternatively, the vertical distance from the convergence point to the projection screen decreases as the radius of the unit lens increases; Alternatively, the vertical distance from the convergence point to the projection screen first increases and then decreases as the radius of the unit lens increases; The vertical distance from the convergence point to the projection screen is linearly related to the radius of the unit lens; When the vertical distance from the convergence point to the projection screen is linearly related to the radius of the unit lens, the following relationship formula is satisfied: Wherein, y is the vertical distance from the convergence point to the projection screen, in millimeters; R is the radius of the unit lens, in millimeters; G is the diagonal size of the projection screen, in inches; a0 and a1 are constants related to the values ​​of y, R, and G, and are expressed in millimeters. a0 and a1 are calculated using the following constant calculation formula: Wherein, R0 and R1 are the radius values ​​of the selected unit lenses with different radii, and y0 and y1 are the preset vertical distances from the convergence point of each unit lens to the projection screen.

9. The projection screen according to claim 8, characterized in that When the diagonal size G of the projection screen is ≤ 100 inches, a1>0, a0>0; when the diagonal size G of the projection screen is > 100 inches, a1<0, a0>0.

10. A projection screen, characterized in that: The projection screen is provided with a microstructure layer for converging projection light. The microstructure layer includes a plurality of unit lenses with sawtooth cross-sections arranged in a concentric ring shape in the plane direction of the projection screen. Each unit lens converges the projection light to a convergence point. All convergence points are located on the same straight line perpendicular to the projection screen. The vertical distance from the convergence point to the projection screen varies continuously with the radius of the unit lens. The vertical distance from the convergence point to the projection screen increases as the radius of the unit lens increases; Alternatively, the vertical distance from the convergence point to the projection screen decreases as the radius of the unit lens increases; Alternatively, the vertical distance from the convergence point to the projection screen first increases and then decreases as the radius of the unit lens increases; The vertical distance from the convergence point to the projection screen is linearly related to the unit lens radius segmentally; When the vertical distance from the convergence point to the projection screen is linearly related to the unit lens radius, the following relationship formula is satisfied: Wherein, y is the vertical distance from the convergence point to the projection screen, in millimeters; R is the radius of the unit lens, in millimeters; G is the diagonal size of the projection screen, in inches; a0 and a1 are constants related to the values ​​of y, R, and G, and are expressed in millimeters. When the radius of the unit lens R≤b, a1>0, and when R>b, a1<0, where b is a preset value within the radius variation range of the unit lens on the microstructure layer; a0 and a1 are obtained by the following constant calculation formula: Among them, R0 and R1 are the radius values ​​of unit lenses with different radii selected within the range of the radius of the unit lens R≤b, or R0 and R1 are the radius values ​​of unit lenses with different radii selected within the range of the radius of the unit lens R≥b, and y0 and y1 are the preset vertical distances from the convergence point of each unit lens to the projection screen.

11. A method for fitting the change of the convergence point of a projection screen according to any one of claims 8 to 10, characterized in that: Select k unit lenses with different radii and set the vertical distance from the convergence point of each unit lens to the projection screen, k ≥ 3, where k is an integer; Select two unit lenses and calculate a0 and a1 according to the constant calculation formula, then select two more unit lenses and calculate a0 and a1 according to the constant calculation formula, and so on to obtain multiple sets of a0 and a1, and calculate the average value as the final value, so as to obtain the relationship formula between the vertical distance from the convergence point to the projection screen and the radius of the unit lens; Among the selected unit lenses, a radius value of one unit lens is half of the maximum radius of the unit lenses on the microstructure layer, and a radius value of at least one unit lens is greater than half of the maximum radius of the unit lenses on the microstructure layer, and a radius value of at least one unit lens is less than half of the maximum radius of the unit lenses on the microstructure layer; Alternatively, among the selected unit lenses, one unit lens passes through the geometric center point of the projection screen, and the radius value of at least one unit lens is greater than the radius value of the unit lens passing through the geometric center point of the projection screen, and the radius value of at least one unit lens is smaller than the radius value of the unit lens passing through the geometric center point of the projection screen.

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