CN116699937A

CN116699937A - Projection screen and projection system

Info

Publication number: CN116699937A
Application number: CN202310548405.8A
Authority: CN
Inventors: 内藤畅夫; 侯蕊
Original assignee: Qingdao Hisense Laser Display Co Ltd
Current assignee: Qingdao Hisense Laser Display Co Ltd
Priority date: 2023-05-16
Filing date: 2023-05-16
Publication date: 2023-09-05

Abstract

The invention discloses a projection screen and a projection system, comprising a surface functional layer, a Fresnel structure layer and a reflecting layer. The Fresnel structure layer comprises a plurality of concentric Fresnel structures which are sequentially expanded along the radial direction, more light rays can be concentrated to the middle position by setting the inclination angles of the inclined surfaces of the Fresnel structure to be larger than the inclination angles of the middle position, so that the gain uniformity of the projection screen is improved to more than 80%, and the gain uniformity of the projection screen can reach 100% through the reasonable inclination angle design.

Description

Projection screen and projection system

Technical Field

The present invention relates to the field of projection technologies, and in particular, to a projection screen and a projection system.

Background

With the continuous development of larger display products, the market of projection display products as large screen products for replacing liquid crystal, organic Electroluminescent (EL) televisions is rapidly expanding in view of power consumption, weight, size, and the like. Laser televisions employing ultra-short focal projection devices are rapidly evolving due to their high image quality and convenience for large screens.

The present projection system can be generally used with a projection screen, and projection light is emitted by the projection device, and is incident on the projection screen, reflected by the projection screen, and incident on human eyes to view a projection image. The Fresnel structure layer is arranged in the projection screen and is used for reflecting projection light emitted by the projection device to the position of a viewer, and Gain uniformity (Gain uniformity) of the projection screen is poor due to astigmatism existing in the Fresnel structure layer.

Disclosure of Invention

In a first aspect of an embodiment of the present invention, there is provided a projection screen, including:

a surface functional layer;

the Fresnel structure layer is positioned on one side of the surface functional layer; the surface of one side of the Fresnel structure layer is provided with a plurality of Fresnel structures, and the Fresnel structures form concentric circles which are sequentially expanded and arranged along the radial direction; the Fresnel structure comprises an inclined surface which is obliquely arranged relative to the plane where the surface functional layer is located; and

A reflection layer covering at least the inclined surface of each fresnel structure of the fresnel structure layer;

the inclination angle of the inclined surface of each Fresnel structure meets the requirement that the light rays of the reflecting layer emitted onto the inclined surface by the projection equipment are reflected towards the direction of a viewer; the inclination angle of the inclined surface of at least one of the plurality of fresnel structures increases as the vertical distance from the inclined surface to the center line of the projection screen increases; the central line of the projection screen is a central axis perpendicular to the horizontal direction.

In some embodiments of the present invention, the center of each fresnel structure in the projection screen is located outside the projection screen, and the inclination angle of the inclined surface of each fresnel structure in the projection screen increases with increasing vertical distance from the inclined surface to the center line of the projection screen.

In some embodiments of the present invention, the change in the inclination angle of the inclined surface of the same fresnel structure satisfies a sine function.

In some embodiments of the present invention, the inclination angle of the inclined surface of each fresnel structure increases along the radial direction with increasing radius of the fresnel structure.

In some embodiments of the present invention, the amplitude of the sinusoidal function satisfied by the inclination angle of the inclined surface of each fresnel structure increases with increasing radius of the fresnel structure.

In some embodiments of the present invention, the change in the inclination angle of the inclined surface of the same fresnel structure is greater than 0 and less than or equal to 2.25 °.

In some embodiments of the present invention, the amount of change in the angle of inclination of the inclined surface of the fresnel structure increases as the size of the projection screen increases.

In some embodiments of the invention, the surface functional layer comprises an anisotropic diffusion layer;

the diffusion angle of the anisotropic diffusion layer along the horizontal direction is larger than the diffusion angle along the vertical direction; the horizontal direction and the vertical direction are perpendicular to each other.

In some embodiments of the present invention, further comprising:

an adhesive layer between the surface functional layer and the fresnel structure layer;

the Fresnel structure of the Fresnel structure layer is positioned on the side opposite to the surface functional layer; the bonding layer is used for bonding the surface functional layer and the surface of the Fresnel structure layer on the side opposite to the Fresnel structure;

alternatively, the fresnel structure of the fresnel structure layer is located on a side facing the surface functional layer; the bonding layer is used for bonding the surface functional layer and the reflecting layer on the Fresnel structure.

In a second aspect of an embodiment of the present invention, there is provided a projection system including:

the projection device is used for emitting projection light; and

The projection screen is positioned on the light emitting side of the projection equipment, and the projection screen is any one of the projection screens;

wherein the projection device is an ultra-short focal laser projection device; the projection apparatus includes:

the three-color laser light source device is used for emitting three-primary-color laser;

the light modulation component is positioned at the light emitting side of the three-color laser light source device and used for modulating the emitted laser of the three-color laser light source device; and

And the projection lens is positioned on the light emitting side of the light modulation component.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a projection system according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of a projection screen according to the related art;

FIG. 3 is a schematic view of a projection effect according to an embodiment of the present invention;

FIG. 4 is a schematic view of a projection screen according to an embodiment of the present invention;

FIG. 5 is a schematic cross-sectional view of a projection screen according to an embodiment of the present invention;

FIG. 6 is a schematic plan view of a Fresnel structure layer according to an embodiment of the present invention;

FIG. 7 is a second schematic view of a projection effect provided by an embodiment of the present invention;

FIG. 8 is a graph showing one of the change curves of the inclination angles of the inclined surface of the Fresnel structure at different positions according to the embodiment of the present invention;

FIG. 9 is a schematic cross-sectional view of the projection screen along the line I-I' of FIG. 6;

FIG. 10 is a second variation curve of the inclination angle of the inclined surface of the Fresnel structure at different positions according to the embodiment of the present invention;

FIG. 11 is a schematic diagram showing a cross-sectional structure of a projection screen according to an embodiment of the present invention;

FIG. 12 is a third schematic cross-sectional view of a projection screen according to an embodiment of the present invention;

FIG. 13 is a schematic cross-sectional view of a projection screen according to an embodiment of the present invention;

FIG. 14 is a schematic plan view of a surface functional layer according to an embodiment of the present invention;

fig. 15 is a schematic structural diagram of a projection apparatus according to an embodiment of the present invention.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a further description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus a repetitive description thereof will be omitted. The words expressing the positions and directions described in the present invention are described by taking the drawings as an example, but can be changed according to the needs, and all the changes are included in the protection scope of the present invention. The drawings of the present invention are merely schematic representations of relative positional relationships and are not intended to represent true proportions.

With the popularization of laser display products, the market of laser televisions is rapidly expanding as a large-screen product for replacing liquid crystal and organic EL televisions. To achieve better brightness and display, projection devices are typically used with projection screens.

Fig. 1 is a schematic diagram of a projection system according to an embodiment of the present invention.

As shown in fig. 1, the projection system includes: a projection device 2 and a projection screen 1.

The projection screen 1 is located on the light emitting side of the projection device 2, the viewer faces the projection screen 1, the projection device 2 emits projection light, the projection light is incident on the projection screen 1 and reflected to the position of the viewer through the projection screen 1, and accordingly the viewer views the projection image.

The ultra-short-focus projection equipment has the characteristics of short projection distance and large projection picture, and is very suitable for being applied to the household field.

Fig. 2 is a schematic view of a structure of a projection screen in the related art.

As shown in fig. 2, a projection screen used in the present front projection system is provided with a fresnel structure layer 12, a reflective layer 13 is disposed on a surface of the fresnel structure layer, and the fresnel structure in the fresnel structure layer can make a light ray L emitted from the projection device 1 incident on the reflective layer 13 on the surface of the fresnel structure layer 12 and reflected toward a position where a viewer is located, so that the projection light ray is incident on a human eye to view a projection image.

Fig. 3 is a schematic view of a projection effect according to an embodiment of the invention.

For ease of illustration, only one fresnel structure 121 is shown in fig. 3, and in practice, each fresnel structure 121 suffers from the same problem. Since the fresnel structure 121 is generally a spherical mirror, that is, the same fresnel structure 121 is located on a spherical mirror with an equal radius of curvature, and astigmatism exists in the spherical mirror itself, as shown in fig. 3, the fresnel structure 121 cannot reflect the incident light to the same position, and the light collecting effect is poor, thereby resulting in poor gain uniformity of the projection screen.

Fig. 4 is a schematic view of a projection screen according to an embodiment of the present invention.

As shown in fig. 4, in calculating the gain uniformity of the projection screen, the embodiment of the present invention equally divides the projection screen into three equal parts along two sides perpendicular to each other, thereby dividing the projection screen into 9 areas S1 to S9, the gain uniformity is measured as a ratio between the average value of the gains of the areas S1, S3, S7, S9 and the gain of the area S5, and the limit of the gain uniformity of the projection screen is about 70% when the gain of S5 is set to be maximum.

In view of this, the embodiments of the present invention provide a projection screen, which can improve gain uniformity of the projection screen.

Fig. 5 is a schematic cross-sectional view of a projection screen according to an embodiment of the present invention.

As shown in fig. 5, a projection screen provided in an embodiment of the present invention includes: a surface functional layer 11, a fresnel structure layer 12 and a reflective layer 13.

In the embodiment of the present invention, the surface functional layer 11 is located at the most surface side of the projection screen, and in addition, the surface functional layer 11 is located at the side closest to the viewer to protect the projection screen, and in addition, the surface functional layer 11 can perform various treatments according to different needs, so as to achieve the effects of enlarging the viewing angle, resisting reflection of ambient light, resisting reflection of light from the ceiling, and the like.

Fig. 6 is a schematic plan view of a fresnel structure layer according to an embodiment of the present invention.

As shown in fig. 5 and 6, the fresnel structure layer 12 is located on one side of the surface functional layer 11, specifically on the opposite side of the surface functional layer 11 from the viewer. A plurality of fresnel structures 121 are arranged according to a set rule on a surface of one side of the fresnel structure layer 12.

The fresnel structure 121 may take different configurations depending on the application and manufacturing process. In the embodiment of the present invention, as shown in fig. 6, each fresnel structure 121 may be formed in a concentric shape that sequentially expands in the radial direction. Because of the size limitation of the projection screen, the projection screen generally only includes a part of concentric fresnel structures, and the center of each concentric fresnel structure is not located in the projection screen, but in a region outside the projection screen, the side of the projection screen near the center is generally the bottom side of the screen, so that the radius of each fresnel structure gradually increases with the direction gradually away from the bottom side.

As shown in fig. 5, each fresnel structure 121 includes an inclined surface x1 and a connecting surface x2 that are connected to each other. The inclined surface x1 is inclined with respect to the surface functional layer 11, and the inclined angle of the inclined surface x1 is set according to the incident angle of the projection light, so that the projection light emitted from the projection device can be reflected in the first direction of the viewer when the projection light is incident on the reflective layer on the surface. The connection surface x2 is used for connecting the inclined surface x1.

The reflecting layer 13 covers at least the inclined surfaces of the fresnel structures 121 of the fresnel structure layer 12, and the inclined surfaces of the fresnel structures have a specific inclination angle, so that the reflecting layer 13 covering the surfaces thereof also has a corresponding inclination angle, thereby enabling projection light to be reflected by the reflecting layer 13 toward the viewer's position when the projection light is incident on the reflecting layer 13 on the surface of the fresnel structure.

In the embodiment of the present invention, the reflective layer 13 may be a metal film formed by an evaporation or sputtering process, where the metal film covers the surface of the fresnel structure 121 and has a uniform thickness, so that the surface of the metal film has the same undulation trend as the fresnel structure, and the surface of the metal film may maintain the reflection angle of the fresnel structure on the incident light during design. The metal thin film may be made of a metal such as aluminum, silver, or titanium, and is not limited herein. When the structure shown in fig. 5 is employed, the reflective layer 13 may be formed on the rear surface of the projection screen by applying aluminum paste, silver paste, or the like.

As shown in fig. 6, the projection screen is generally rectangular and includes four sides, adjacent sides being perpendicular to each other. In use, the projection screen will typically be mounted on a wall or suspended at a height, with the bottom and top sides generally parallel to the horizontal direction x and the sides perpendicular to the horizontal direction. In the embodiment of the present invention, the central axis perpendicular to the bottom side edge in the projection screen is referred to as a central line I-I ', and each fresnel structure 121 is axisymmetrically distributed about the central line I-I ', and the center of each concentric fresnel structure is located on the central line I-I '.

In the embodiment of the present invention, the fresnel structure layer 12 includes a plurality of fresnel structures 121, the inclination angles of the inclined surfaces of the same fresnel structure 121 are different within the same circle, and the inclination angle of the inclined surface x1 of at least one fresnel structure 121 increases as the vertical distance from the inclined surface x1 to the center line I-I' increases. As shown in fig. 6, each fresnel structure 121 may be divided into left and right portions along a center line I-I', wherein the inclination angle of the inclined surface x1 of the fresnel structure on the left side gradually increases along the direction xl and the inclination angle of the inclined surface x1 of the fresnel structure on the right side gradually increases along the direction xr. The inclination angles of the inclined surfaces of the same fresnel structure are symmetrically arranged about the center line I-I ', that is, the inclination angles of the inclined surfaces of the same fresnel structure 121 at positions where the vertical distances from the left and right sides to the center line I-I' are equal.

FIG. 7 is a second schematic view of the projection effect provided by the embodiment of the invention.

According to the embodiment of the invention, the inclination angle of the inclined surface of at least one Fresnel structure is set to be increased along with the increase of the vertical distance between the inclined surface and the central line, namely, the inclination angle of the inclined surface at two side positions in the same Fresnel structure is larger, as shown in fig. 7, so that more light rays incident to two sides can be concentrated to the middle position. As can be seen from comparing fig. 4 and fig. 7, the light collecting effect of the fresnel structure can be optimized by the above arrangement of the present invention, thereby improving the gain uniformity of the projection screen.

Based on the above principle, in order to concentrate more light at the edge of the projection screen to the central position and improve gain uniformity of the projection screen, in the embodiment of the invention, all fresnel structures in the projection screen are set to have inclination angles of inclined planes which are increased along with the increase of the vertical distance from the inclined plane to the central line of the projection screen, so that the light can be concentrated to the central position to the greatest extent.

As shown in fig. 6, if the intersection point between the fresnel structure 121 and the bottom side edge of the projection screen is a or D, the intersection point between the fresnel structure and the middle line I-I 'is C, and the intersection point between the upper side edge of the projection screen and the middle line I-I' is B, the inclination angles of the inclined planes at the respective positions of the fresnel structure satisfy the rule shown in fig. 8, and fig. 8 is one of the change curves of the inclination angles of the inclined planes of the fresnel structure at the different positions provided in the embodiment of the invention, as can be seen from fig. 8, the change of the inclination angle of the inclined plane of the same fresnel structure satisfies the sine function, and the inclination angle of the inclined plane of the fresnel structure gradually becomes smaller from the position a to the position B to the position D and then gradually becomes larger, and is changed in a sine curve.

For a fresnel structure 121, the a/D position is the position of the fresnel structure near the edges of the projection screen on both sides and the B position is the middle position of the fresnel structure. In order to make the Fresnel structure concentrate the light rays on two sides to the middle position, the inclination angles of the inclined surfaces of the Fresnel structure on the two sides are larger than those of the middle position, so that the light rays are reflected to the middle position more after entering the Fresnel structure, and the effect of concentrating light to the middle is achieved.

Fig. 9 is a schematic cross-sectional view of the projection screen along the line I-I' in fig. 6.

As shown in fig. 9, the projection device generally emits the projection light L to the projection screen at a lower middle position of the projection screen, and because the position of the projection device is fixed, the incident angle and the direction of the projection light L when the projection light L is incident to different positions of the projection screen are different, so that the projection light can be reflected to the position where the viewer is located, it is necessary to design each fresnel structure to be concentric circles which sequentially expand in the radial direction, and the inclination angles of the inclined surfaces x1 of each fresnel structure are different along the same radial direction. In the embodiment of the invention, the inclination angle of the inclined surface of each Fresnel structure increases along the radial direction along with the increase of the radius of the Fresnel structure.

Taking fig. 9 as an example, since the inclination angle of the inclined surface of the same fresnel structure varies at different positions (for example, A, B, D positions), the inclination angle of the inclined surface of each fresnel structure is not comparable along different directions, but the inclination angle of the inclined surface x1 of each fresnel structure increases in order along the same direction as the radial direction y in fig. 9, that is, the inclination angle of the inclined surface x1 of each fresnel structure satisfies the following conditions: θ1< θ2< θ3. The inclination of the inclined surface of the fresnel structure, which is closer to the edge of the projection screen, needs to be set larger in order that the projection light incident on the fresnel structure can be reflected toward the intermediate position, and therefore the inclination angle of the inclined surface of the fresnel structure needs to be set to a tendency to increase with an increase in radius in the radial direction.

Fig. 10 is a second curve of the inclination angle of the inclined surface of the fresnel structure at different positions according to the embodiment of the present invention.

As shown in fig. 10, the change rule of the inclination angle of the inclined surface of each fresnel structure satisfies a sine function, and the larger the radius, the larger the fresnel structure occupies in the plane where the projection screen is located, and therefore the more severe the change of the inclination angle of the inclined surface of the fresnel structure from the edge position to the intermediate position, the larger the amplitude of the sine curve is reflected on the sine curve that it satisfies. Then, according to the above-described rule, the amplitude of the sine function satisfied by the inclination angle of the inclined surface of each fresnel structure in the embodiment of the present invention increases as the radius of the fresnel structure increases. Taking fig. 10 as an example, the sinusoidal curve f1 represents a change rule of the inclination angle of the inclined surface of the fresnel structure with a larger radius, the sinusoidal curve f2 represents a change rule of the inclination angle of the inclined surface of the fresnel structure with a smaller radius, and as can be seen from fig. 10, the amplitude of the sinusoidal curve f1 satisfied by the inclination angle of the inclined surface of the fresnel structure with a larger radius is larger than the amplitude of the sinusoidal curve f2 satisfied by the inclination angle of the inclined surface of the fresnel structure with a smaller radius.

The projection screen provided by the embodiment of the invention can be used with ultra-short focal projection equipment, and can project large-size images, and the radius of the Fresnel structure is within 2000mm according to the current projection screen size, so that the variation (m in fig. 10) of the inclination angle of the inclined surface of the same Fresnel structure is more than 0 and less than or equal to 2.25 degrees. And as the radius of the fresnel structure increases, the amount of change in the inclination angle of the inclined surface thereof gradually increases, and experiments prove that the amount of change in the inclination angle of the inclined surface of the fresnel structure increases as the size of the projection screen increases. When the radius of the Fresnel structure is within 2000mm, the maximum variation of the inclination angle of the inclined surface of the same Fresnel structure is not more than 2.25 degrees.

It should be noted that the embodiments of the present invention are only illustrated in the case where the radius of the fresnel structure in the projection screen is within 2000mm, and when the size of the projection screen is further increased so that the radius of the fresnel structure exceeds 2000mm, the amount of change in the inclination angle of the inclined surface of the fresnel structure may exceed 2.25 °. The embodiment of the invention does not limit specific numerical values of the variation.

Fig. 11 is a second schematic diagram of a projection screen according to an embodiment of the invention.

As shown in fig. 5 and 11, the projection screen further includes: and an adhesive layer 14, wherein the adhesive layer 14 is positioned between the surface functional layer 11 and the Fresnel structure layer 12, and is used for bonding the surface functional layer 11 and the Fresnel structure layer 12. The adhesive layer 14 may be an acrylic or silicon adhesive, or a UV curable resin material, and is not limited thereto.

In some embodiments, as shown in FIG. 5, the Fresnel structure 121 of the Fresnel structure layer 12 is located on the opposite side of the surface functional layer 11 and the bonding layer 14 is used to bond the surface functional layer 11 to the surface of the Fresnel structure layer 12 on the opposite side of the Fresnel structure 121.

In some embodiments, as shown in FIG. 11, the Fresnel structure 121 of the Fresnel structure layer 12 is located on the side facing the surface functional layer 11, and the adhesive layer 14 is used to adhere the surface functional layer 11 to the reflective layer 13 on the surface of the Fresnel structure 121. When the fresnel structure 121 is disposed on the side close to the adhesive layer 14, the adhesive layer 14 can protect the reflective layer 13, and since the fresnel structure layer 12 is located on the side farthest from the viewer and no light is incident into the fresnel structure layer 12, the requirements on the light transmittance and damage of the fresnel structure layer 12 are reduced, and expensive optical materials are not required to manufacture the fresnel structure layer 12, and cheaper industrial materials can be used for manufacture, thereby reducing the production cost.

In some embodiments, as shown in fig. 11, the fresnel structure layer 12 includes a first substrate 122, and the surface of the first substrate 122 facing the surface functional layer 11 and the surface opposite to the surface functional layer 11 are both flat surfaces, and the fresnel structure 121 is located on the first substrate 122.

The first substrate 122 may be made of Polyethylene terephthalate (Polyethylene Terephthalate, PET), polyethylene naphthalate (Polyethylene Naphthalate, PEN), polycarbonate (PC), polymethyl methacrylate (Polymethyl Methacrylate, PMMA), cellulose Triacetate (TAC), cyclic olefin polymer (Cyclo Olefin Polymer, COP), thermoplastic polyurethane (Thermoplastic Polyurethane, TPU), polyvinyl chloride (Polyvinyl chloride, PVC), polyimide (PI), polyamide (PA), polyethylene (PE), polypropylene (PP), and the like.

The fresnel structure 121 may be formed by applying an ultraviolet curable resin to a mold having the fresnel structure, and performing ultraviolet curing while imprinting the ultraviolet curable resin with the first substrate 122. In addition, other materials may be used in combination with other manufacturing methods to manufacture the fresnel structure 121, which is not limited herein.

Fig. 12 is a third schematic view of a projection screen according to an embodiment of the invention.

In some embodiments, as shown in FIG. 12, the Fresnel structure layer 12 is a unitary structure, one side surface of the Fresnel structure layer 12 being a Fresnel structure 121 and the other side surface being a flat surface. The fresnel structure layer 12 with an integral structure can omit the process of combining the base material and the fresnel structure, and further simplify the manufacturing process. The integrally formed fresnel structure layer 12 may be formed by thermoforming and is not limited in this regard.

Fig. 13 is a schematic structural diagram of a projection screen according to an embodiment of the present invention, and fig. 14 is a schematic planar structural diagram of a surface functional layer according to an embodiment of the present invention.

In some embodiments, the surface functional layer 11 has a light diffusion function, and as shown in fig. 13, the surface functional layer 11 may include: a second substrate 111 and a diffusion layer 112.

The second substrate 111 serves as a substrate for the diffusion layer 112, the second substrate 111 being in contact with the adhesive layer 14, the diffusion layer 112 being located on a surface of the second substrate 111 on the opposite side from the adhesive layer 14.

The existing projection system generally adopts a laser light source, and laser has higher collimation, so that the divergence angle of projection light is smaller, the collimation of the light reflected by a projection screen is high, and the view angle is smaller. By providing the diffusion layer 112, the outgoing angle of the light passing through the diffusion layer can be diversified, so that the light finally outgoing from the projection screen has a certain divergence angle, and the viewing angle of the audience watching the projection image is increased. In addition, the diffusion layer 112 is advantageous in suppressing the generation of laser speckle and optimizing the projected image.

The diffusion layer 112 may be formed on the surface of the second substrate 111 by including diffusion particles in the resin material. The diffusion particles may be, but are not limited to, silica particles, alumina particles, titania particles, ceria particles, zirconia particles, tantalum oxide particles, zinc oxide particles, magnesium fluoride particles, and the like.

The second substrate 111 may be, but is not limited to, PET, PEN, PC, PMMA, TAC, COP, TPU, PVC, PI, PA, PE, PP.

In the embodiment of the present invention, the diffusion layer 112 is an anisotropic diffusion layer, and the anisotropic diffusion layer refers to a diffusion angle in different directions. As shown in fig. 14, the diffusion angle of the anisotropic diffusion layer along the horizontal direction x is larger than the diffusion angle along the vertical direction y, the horizontal direction x and the vertical direction y are different directions in the plane of the projection screen, and the horizontal direction x is parallel to the bottom side edge of the projection screen; the vertical direction y is perpendicular to the horizontal direction and parallel to the center line I-I' of the projection screen. The vertical direction y corresponds to the height direction of the viewer viewing the projection screen, and if the diffusion angle of the diffusion layer in the vertical direction is larger, light from the ceiling is also diffused, resulting in an increase in the black field luminance of the projection screen. The diffusion layer has a large diffusion angle in the horizontal direction, so that the viewing angle in the left-right direction of the projection screen can be diffused. Therefore, in the embodiment of the invention, the anisotropy that the diffusion angle of the diffusion layer along the horizontal direction x is larger than the diffusion angle of the diffusion layer along the vertical direction y is applied, so that the view angle of the projection screen along the horizontal direction can be increased, and the increase of the brightness of the black field can be avoided.

In the embodiment, the diffusion layer is structured such that ridge lines are arranged in the vertical direction y, whereby the effect that the diffusion angle in the horizontal direction x is larger than the diffusion angle in the vertical direction y can be achieved.

As shown in fig. 4, in the related art, in the case where the inclination angle of the inclined surface of the same fresnel structure is constant, the fresnel structure is a spherical mirror, and astigmatism occurs, so that the regions S1, S4, and S7 and the regions S3, S6, and S9 of the projection screen emit light to both sides in the horizontal direction, and thus the gain uniformity of the projection screen is deteriorated. When an anisotropic diffusion layer having a diffusion angle in the vertical direction y smaller than that in the horizontal direction x is used, the gain uniformity of the projection screen is further lowered due to an increase in the diffusion in the horizontal direction. If the inclination angle of the inclined surface of the fresnel structure is increased to suppress the spread of light in the horizontal direction, light rays at the positions of the regions S2 and S5 of the projection screen are emitted downward, resulting in a reduction in front brightness of the projection screen. Therefore, in order to overcome the above problems, the diffusion angle of the diffusion layer in the vertical direction y is increased so that the light can be further diffused from below to above, thereby improving the gain uniformity of the projection screen. As described above, an increase in the diffusion angle of the diffusion layer in the vertical direction y causes an increase in the black field luminance, and still affects the display effect.

According to the embodiment of the invention, the inclination angle of the inclined surface of the Fresnel structure is set to be larger than that of the middle position, so that more light rays can be concentrated towards the middle position, and meanwhile, the anisotropic diffusion layer with the diffusion angle of the horizontal direction x being larger than that of the vertical direction y is matched, so that the brightness of the projection screen in the areas S2 and S5 can be reduced while the brightness reduction of the projection screen is restrained.

The embodiment of the invention also tests the gain uniformity of the projection screen manufactured according to the inventive concept. The specific manufacturing process is as follows: a Fresnel structure of 80inch was fabricated on the surface of a 250 μm thick PET substrate. Then, a reflective layer is formed on the surface of the fresnel structure by vapor deposition of aluminum. Next, an anisotropic diffusion layer having a smaller diffusion angle in the vertical direction than in the horizontal direction was formed on the surface of the 250 μm thick PET substrate. And bonding the two PET substrates with each other through transparent bonding glue to obtain the projection screen.

As shown in fig. 4, the gain uniformity of the projection screen was measured in the same manner as the ratio between the average value of the gains of the regions S1, S3, S7, S9 and the gain of the region S5. The inclination angles of the inclined surfaces of the Fresnel structure in the projection screen are set to be larger than those of the middle positions, so that the gain uniformity of the projection screen can be improved to be more than 80%, and the gain uniformity of the projection screen can be 100% through reasonable inclination angle design.

Based on the same inventive concept, an embodiment of the present invention further provides a projection system, as shown in fig. 1, including: a projection device 2 and a projection screen 1 located at the light exit side of the projection device 2.

As shown in fig. 15, the projection apparatus includes: a light source device 21, an illumination light path 22, a light modulation section 23, and a projection lens 24. The illumination light path 22 is located on the light emitting side of the light source device 21, the light modulation member 23 is located on the light emitting side of the illumination light path 22, and the projection lens 24 is located on the light emitting side of the light modulation member 23.

The light source device 21 may be a laser light source device. The laser light source device can adopt a monochromatic laser or a laser capable of emitting laser light with various colors or a plurality of lasers emitting laser light with different colors. When the laser light source device adopts a monochromatic laser, the laser display device also needs to be provided with a color wheel which is used for carrying out color conversion, and the monochromatic laser can realize the purpose of emitting the primary color light of different colors according to time sequence by matching with the color wheel. When the laser light source device uses a laser capable of emitting laser beams of a plurality of colors, it is necessary to control the laser light source to emit laser beams of different colors as primary light in time series.

In the embodiment of the invention, the light source device can adopt a three-color laser light source device, and the three-color laser light source device can be a laser emitting three-primary-color lasers, such as an MCL laser and the like; the laser device can also comprise a red laser, a green laser and a blue laser which respectively emit three primary colors of laser. The three-color laser light source device is beneficial to improving the color gamut of the projection image, has better color expressive force and can accurately reproduce the input image.

The illumination light path 22 is positioned on the light-emitting side of the light source device 21, and the illumination light path 22 collimates the light emitted from the light source device 21, and allows the light emitted from the light source device 21 to enter the light modulation member 23 at an appropriate angle. The illumination path 22 may include a plurality of lenses or lens groups, and is not limited herein.

The light modulation section 23 is for modulating the incident light. In particular, the light modulation section 23 may employ a digital micromirror (Digital Micromirror Device, DMD for short). After passing through illumination path 22, the beam meets the illumination size and angle of incidence required by the DMD. The DMD surface includes a plurality of tiny mirrors, each of which is individually actuated to deflect, and by controlling the angle of deflection of the DMD, the intensity of the light incident on the projection lens 24 is controlled.

The projection lens 24 is used for imaging the outgoing light of the light modulation part 23, and projecting the imaging after the imaging by the projection lens 24.

In an embodiment of the present invention, the projection device 2 may be an ultra-short focal projection device, that is, the projection lens 24 in the projection device is an ultra-short focal projection lens. The adoption of the ultra-short focal projection device can greatly shorten the distance between the projection device 2 and the projection screen 1, and can realize large-size image display while shortening the projection distance.

The projection screen 1 is located on the light exit side of a projection lens in a projection device. The projection screen 1 comprises a surface functional layer, a fresnel structure layer and a reflective layer. The Fresnel structure layer comprises a plurality of concentric Fresnel structures which are sequentially expanded along the radial direction, more light rays can be concentrated to the middle position by setting the inclination angles of the inclined surfaces of the Fresnel structure to be larger than the inclination angles of the middle position, so that the gain uniformity of the projection screen is improved to more than 80%, and the gain uniformity of the projection screen can reach 100% through the reasonable inclination angle design.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. A projection screen, comprising:

a surface functional layer;

2. The projection screen of claim 1, wherein the center of each fresnel structure in the projection screen is located outside the projection screen, and the angle of inclination of the inclined surface of each fresnel structure in the projection screen increases as the vertical distance of the inclined surface from the midline of the projection screen increases.

3. The projection screen of claim 2, wherein the change in the angle of inclination of the inclined surfaces of the same fresnel structure satisfies a sinusoidal function.

4. A projection screen according to claim 3, wherein the angle of inclination of the inclined surface of each fresnel structure increases radially with increasing radius of the fresnel structure.

5. The projection screen of claim 4, wherein the amplitude of the sinusoidal function satisfied by the angle of inclination of the angled surface of each fresnel structure increases as the radius of the fresnel structure increases.

6. The projection screen of claim 5, wherein the angle of inclination of the inclined surfaces of the same fresnel structure varies by more than 0 and less than or equal to 2.25 °.

7. The projection screen of claim 6, wherein the amount of change in the angle of inclination of the angled surface of the fresnel structure increases as the size of the projection screen increases.

8. The projection screen of any of claims 1-7, wherein the surface functional layer comprises an anisotropic diffusion layer;

9. The projection screen of claim 8, further comprising:

10. A projection system, comprising:

the projection device is used for emitting projection light; and

A projection screen positioned on the light exit side of the projection device, the projection screen being as claimed in any one of claims 1 to 9;