CN106125317A - The structure of a kind of optics display film and preparation method - Google Patents

Abstract

The invention discloses a structure and a preparation method of an optical display film. The preparation method of the display film is as follows: coating the first side and the second side of a high-temperature resistant polyester thin PET film with a liquid curing glue, wherein , the first side is opposite to the second side; forming a plurality of microlenses with an elliptical structure, wherein the plurality of microlenses are arranged in a matrix; embossing a plurality of microlenses with an elliptical structure on the Embossing a preset pattern on the first side of the PET film and on the second side of the PET film, wherein the preset pattern is provided with a grating structure of a binary diffraction grating; through a light source irradiating, forming the plurality of microlenses having an elliptical structure on the first side of the PET film, and forming the preset pattern on the second side of the PET film. The preparation method of the display film realizes a display effect of high definition, large viewing angle and dynamic 3D.

Description

Structure and preparation method of an optical display film

technical field

The invention relates to the technical field of imaging of microlens arrays, in particular to a structure and preparation method of an optical display film.

Background technique

The microlens array imaging technology provides a new observation method, which uses the refraction of the microlens to modulate the micrographics and text array, forming a dynamic effect with horizontal parallax and vertical parallax in space. This technology is an example of the combination of classical theory and modern technology. From the perspective of optical principle, it is the imaging theorem in geometric optics hundreds of years ago, but its application adopts contemporary microelectronic plate making and advanced production technology. Based on the imaging technology of microlenses, researchers have researched and invented many display films and applied them to our actual production and life.

There is a kind of laser film in the prior art, which generally adopts computer lattice lithography technology, 3D true color holographic technology, multiple and dynamic imaging technology, etc., and transfers the holographic image with rainbow dynamics and three-dimensional effect to PET ( Polyethylene terephthalate, polyethylene terephthalate), BOPP (Biaxially OrientedPolypropylene, biaxially oriented polypropylene film), PVC (Polyvinyl chloride, polyvinyl chloride) or coated substrates, and then use composite, ironing Printing, transfer and other methods make the surface of commodity packaging obtain a certain laser laser effect. However, the laser film is still a single-layer film structure, which cannot achieve dynamic effects.

Traditional display films are all single-sided structures, and the microlens arrays of the display film are all spherical microlenses. Inherent aberrations and small viewing angles affect the final display effect.

Contents of the invention

The purpose of the embodiment of the present invention is to provide a structure and preparation method of an optical display film, improve the aberration in the imaging process of the traditional single-sided display film, and provide a clearer and larger viewing area image, so as to realize the image High-definition, large viewing angle dynamic 3D display effect.

In order to achieve the above purpose, the embodiment of the present invention discloses a structure of an optical display film, including:

A plurality of microlenses having an elliptical structure, wherein the plurality of microlenses are arranged in a matrix;

A thin PET film of high temperature resistant polyester, the first side of the PET film is provided with the microlens, and the second side of the PET film is provided with a preset pattern, wherein the preset pattern is provided with binary In the grating structure of the diffraction grating, the first side is opposite to the second side.

Preferably, a predetermined pattern is embossed on the second side of the PET film.

Preferably, the preset pattern is engraved with a grating structure of a binary diffraction grating.

Preferably, the eccentricity of the microlens is e, wherein the e is:

Where y is the height of the incident light on the aspheric surface, x is the rotational symmetry axis of the aspheric surface, is the radius of curvature of the vertex.

Preferably, the diffraction angle θ of the binary diffraction grating is:

The period b of the binary diffraction grating is:

The groove depth d of the binary diffraction grating is:

Wherein the wavelength of the incident light wave of the binary diffraction grating is λ, the refractive index of the material of the binary diffraction grating is n, and the aperture of the microlens is p.

In order to achieve the above purpose, the embodiment of the present invention also discloses the preparation method of the display film, including:

The first side and the second side of the high-temperature-resistant polyester thin PET film are covered with liquid curing glue, wherein the first side is opposite to the second side;

forming a plurality of microlenses with an elliptical structure, wherein the plurality of microlenses are arranged in a matrix;

embossing a plurality of microlenses with an elliptical structure on the first side of the PET film, and embossing a preset pattern on the second side of the PET film, wherein the preset a grating structure patterned with a binary diffraction grating;

The plurality of microlenses having an elliptical structure are formed on the first side of the PET film and the preset pattern is formed on the second side of the PET film by irradiation of a light source.

Preferably, said forming a plurality of microlenses with an elliptical structure includes:

by formula form an elliptical structure;

According to the elliptical structure, a plurality of microlenses with an elliptical structure are formed, wherein, y is the height of the incident light on the aspheric surface, x is the rotational symmetry axis of the aspheric surface, is the radius of curvature of the vertex, and e is the eccentricity of the curve.

Preferably, the said passing formula Form an elliptical structure consisting of:

Through the aberration balancing algorithm, the formula The e in is adjusted to the default value;

According to the preset value, a plurality of microlenses having an elliptical structure are formed.

Preferably, embossing a plurality of microlenses with an elliptical structure on the first side of the PET film, and embossing a preset pattern on the second side of the PET film, include:

embossing a plurality of microlenses having an elliptical structure on the first side of the PET film by means of a roll having a plurality of microlenses wrapped in a nickel plate, and

A preset pattern is embossed on the second side of the PET film by a roller wrapped with the preset pattern nickel plate.

Preferably, the plurality of microlenses having an elliptical structure are formed on the first side of the PET film through the irradiation of a light source, and the microlenses are formed on the second side of the PET film. The preset patterns mentioned above include:

The plurality of microlenses having an elliptical structure are formed on the first side of the PET film and the preset pattern is formed on the second side of the PET film by irradiation of an ultraviolet light source.

In the structure and preparation method of the display film of the present invention, by embossing a plurality of microlenses with an elliptical structure on the first side of the PET film, and embossing two microlenses on the second side of the PET film The preset pattern of the grating structure of the meta-diffraction grating, the image information passes through the preset pattern and then through the imaging of multiple elliptical micro-lenses, which improves the aberration in the imaging process of the traditional single-sided display film and provides the observer with A clearer image display effect. At the same time, compared with the traditional spherical microlens, the elliptical microlens provides a larger viewing area. The image information is processed through the preset pattern to achieve a more colorful dynamic As a result, what is finally presented to the observer is a high-definition, large viewing angle, and dynamic 3D image display, which is an excellent viewing effect for the observer. Of course, implementing any product or method of the present invention does not necessarily need to achieve all the above-mentioned advantages at the same time.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a structural diagram of a display film according to an embodiment of the present invention;

2 is a flow chart of a method for preparing a display film according to an embodiment of the present invention;

Fig. 3 is the specific relationship diagram of the aspheric curve of the prior art;

4 is a schematic diagram of a microlens structure of an elliptical structure according to an embodiment of the present invention;

5 is a schematic diagram of a three-dimensional model of a microlens with an elliptical structure according to an embodiment of the present invention;

FIG. 6 is a spatial perspective arrangement diagram of a plurality of microlenses with an elliptical structure according to an embodiment of the present invention;

7 is a schematic diagram of the light emitted by the edge pixel A of the embodiment of the present invention concentrating the light on the microlens with an elliptical structure through a binary diffraction grating;

Fig. 8 is a structural diagram of a binary diffraction grating according to an embodiment of the present invention;

Fig. 9 is an effect diagram of rotation dynamic change according to the embodiment of the present invention;

Fig. 10 is a two-dimensional transformation effect diagram of an embodiment of the present invention;

Fig. 11 is a diagram of an apparatus for manufacturing a display film according to an embodiment of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The purpose of the embodiments of the present invention is to invent a structure and a preparation method of a display film. In this solution, the display film is a double-sided display film with a two-layer structure, the microlens is provided on the first side of the high-temperature resistant polyester thin PET film, and a preset pattern is provided on the second side, wherein the The preset pattern is provided with a grating structure of a binary diffraction grating, and the first side is opposite to the second side. The image information first passes through a preset pattern with a grating structure, is processed by the diffraction of the binary grating and the code set on the preset pattern, and is imaged by the microlens with an elliptical structure, and finally on the microlens with an elliptical structure It presents a high-definition, large viewing angle, and dynamic 3D display effect to the observer.

The present invention will be described in detail below through specific examples.

As shown in Figure 1, Figure 1 is a structural diagram of a display film according to an embodiment of the present invention, and the structure of the display film includes:

A plurality of microlenses 101 having an elliptical structure, wherein the plurality of microlenses 101 are in a matrix;

In this embodiment, the shape of the surface of the microlens is obtained as an ellipse by a formula, and the microlens 101 with an elliptical structure is optimized by an aberration balance algorithm. In the aberration balance algorithm, the value of the eccentricity e of the microlens is obtained. The parameters of the elliptical microlens 101 are determined. Compared with the traditional spherical microlens, the elliptical microlens 101 has a smaller aberration and a larger viewing area.

Preferably, in this embodiment, the eccentricity of the microlens is e, wherein the e is:

Where y is the height of the incident light on the aspheric surface, x is the rotational symmetry axis of the aspheric surface, is the radius of curvature of the vertex.

PET film 102, Polyethylene terepthalate polyethylene terephthalate referred to as PET,

A preset pattern is arranged on the second side of the PET film 102,

The first side of the PET film 102 is provided with the microlens, and the second side of the PET film 102 is provided with a preset pattern, wherein the preset pattern is provided with a grating structure of a binary diffraction grating 103 , the first side is opposite to the second side.

Preferably, a predetermined pattern is embossed on the second side of the PET film 102 , and the predetermined pattern is engraved with the grating structure of the binary diffraction grating 103 .

Preferably, a binary diffraction grating 103 is engraved on the preset pattern, and the binary diffraction grating 103 can concentrate light to the paraxial region of the microlens through diffraction to improve aberrations. There is encoding, which can realize the dynamic display effect of image information. In the embodiment, by inputting the pre-set code and the required direction of light control into the photolithography machine, a preset pattern with a binary diffraction grating structure can be formed on the photoresist plate through photolithography technology.

The microlens on the traditional display film is a spherical microlens, and the pattern formed by the code is realized by flat printing, and the structure is a single-sided structure. In addition, the laser film that appears in the prior art is also a single-sided structure. The display of this embodiment The film is a double-sided structure, which greatly reduces the aberration in imaging compared with the traditional single-sided display film structure, and the imaging quality is higher.

As shown in Figure 2, Figure 2 is a flow chart of the preparation method of the membrane shown in the embodiment of the present invention, and the specific process is as follows:

Step 201, coating the first side and the second side of the high-temperature-resistant polyester thin PET film with a liquid curing glue, wherein the first side is opposite to the second side;

Step 202, forming a plurality of microlenses with an elliptical structure, wherein the plurality of microlenses are arranged in a matrix;

Step 203, embossing a plurality of microlenses with an elliptical structure on the first side of the PET film, and embossing a preset pattern on the second side of the PET film, wherein the The preset pattern is provided with a grating structure of a binary diffraction grating;

Step 204, forming the plurality of microlenses with an elliptical structure on the first side of the PET film by illuminating the light source, and forming the preset lens on the second side of the PET film pattern.

As shown in FIG. 3 , FIG. 3 is a specific relationship diagram of aspheric curves in the prior art. Aberration is the inherent nature of microlens imaging. The existence of aberration greatly affects the imaging quality of microlens. Therefore, in order to provide a clear display effect, we reduce the aberration and improve the image quality by designing the microlens. clarity. In the design process of the microlens, the first problem we need to solve is clear imaging, that is, to improve the imaging quality. For this reason, the following examples are analyzed:

Preferably, the preparation method of the display film, the formation of a plurality of microlenses with an elliptical structure includes:

by formula form an elliptical structure;

According to the elliptical structure, a plurality of microlenses with an elliptical structure are formed, wherein, y is the height of the incident light on the aspheric surface, x is the rotational symmetry axis of the aspheric surface, is the radius of curvature of the vertex, and e is the eccentricity of the curve. Under the condition of the same lens aperture and radius of curvature, by adjusting the value of e to achieve the purpose of reducing aberration, we can obtain a microlens with an elliptical surface structure. In this embodiment, the elliptic curve we used e is 1>e ² >0.

As shown in FIG. 4 , FIG. 4 is a schematic structural diagram of a microlens with an elliptical structure according to an embodiment of the present invention.

Preferably, in the preparation method of the display film, the formula Form an elliptical structure consisting of:

Through the aberration balancing algorithm, the formula The e in is adjusted to the default value;

According to the preset value, a plurality of microlenses having an elliptical structure are formed.

The microlens with elliptical structure is determined by solving the aberration balance equation by adjusting the value of e. The microlens with elliptical structure is the microlens with optimal elliptical structure for imaging, but it is not limited to one of the specifications. A lens with an elliptical structure. According to the aberration balance algorithm, when the preset eccentricity of the elliptic curve is e ² =0.396, the imaging display effect is the best, so other parameters of the microlens with the elliptical structure can be determined. The parameters of the microlens of this elliptical structure are: the radius of curvature of the apex is The crown height of the microlens is h=0.0087mm, the aperture of the microlens is P=0.03175mm, and the refractive index is n=1.56. These parameters can uniquely determine the specifications of the microlens with an elliptical structure.

As shown in FIG. 5, FIG. 5 is a schematic diagram of a three-dimensional model of a microlens with an elliptical structure according to an embodiment of the present invention, wherein one side of the display film is formed by a plurality of preset microlenses arranged in a matrix.

In the embodiment of the present invention, through the design of the microlens, compared with the traditional spherical microlens, the microlens with an elliptical structure effectively reduces the aberration and improves the definition of imaging.

Another important problem to be solved in the design of the microlens with the elliptical microstructure is to increase the viewing area. Detailed description below

In this embodiment, as shown in FIG. 6 , FIG. 6 is a spatial viewpoint arrangement diagram of multiple elliptical microlenses in the embodiment of the present invention, 601 is a coded pixel, 602 is a plurality of elliptical microlenses, 603 is arranged for the pilot space. Figure 6 shows the arrangement of the experimental points formed by the image information through the microlens imaging in the elliptical structure in the horizontal direction of space. The situation in the vertical direction is the same. We will take 16 viewpoints as an example to illustrate in detail.

From Figure 6, we can see that, taking the one-dimensional horizontal direction as an example, each microlens with an elliptical structure covers 16 pixels in the horizontal direction, and these 16 pixels are derived from 16 different sequence diagrams. The refraction effect of the micro-lens 602 in the elliptical structure arranges the viewpoints in space. Among them, T is the viewing area, P is the aperture of the microlens, and L is the viewing distance. Similarly, the vertical direction also covers 16 pixels, so each microlens with an elliptical structure can cover 256 pixels. They come from 256 sequence diagrams.

According to the basic imaging theorem of microlenses, the formulas displayed by multiple microlenses are obtained:

$\frac{\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; ,</span>$

Where f is the focal length of the microlens, P is the aperture of the microlens, L is the viewing distance, and T is the viewing cycle, which is the range of the viewing area. It can be seen from the formula that when the viewing distance L is constant, the size of the viewing period depends on the ratio of the focal length f to the aperture P. The smaller the ratio, the larger the viewing period.

For conventional spherical microlenses, the minimum value of f/P is 1 when the refractive index is 1.5. For microlenses with an elliptical structure, the ratio can be adjusted to make the ratio less than 1 according to the adjustment of the conic coefficient, so as to achieve the purpose of increasing the viewing area. At the same time, for the traditional spherical microlens, when the value of f/P is equal to 1, the microlens is equivalent to a hemisphere, and the imaging quality of the microlens is very poor at this time, and it is not so good for the microlens with elliptical structure. big impact. Therefore, the microlens with elliptical structure can not only effectively improve the imaging quality, but also is a good choice for increasing the viewing area.

In the embodiment of the present invention, the other side of the prepared display film is the preset pattern, and the preset pattern is engraved with a binary diffraction grating structure, and the design of the binary diffraction grating is as follows.

As shown in FIG. 7 , FIG. 7 is a schematic diagram of the light emitted by the edge pixel A passing through the binary diffraction grating to concentrate the light on the microlens with an elliptical structure according to the embodiment of the present invention. The light emitted by pixel A in the figure concentrates the light near the principal ray in the paraxial region of the microlens with elliptical structure through the diffraction of the binary grating, where θ is the diffraction angle of the principal ray. The function of the binary diffraction grating is to directional diffract the light emitted by the preset pattern pixels to the paraxial region of the corresponding elliptical microlens to further reduce the influence of aberrations, because the beam near the chief ray contains the main part of the divergent beam Energy, so the principal ray is taken as an example to illustrate the principle of binary grating modulation.

As shown in FIG. 8 , FIG. 8 is a structure diagram of a binary diffraction grating according to an embodiment of the present invention. We design a binary diffraction grating by taking chief rays as an example.

Preferably, the diffraction angle θ of the binary diffraction grating is:

The period b of the binary diffraction grating is:

The groove depth d of the binary diffraction grating is: Wherein the wavelength of the incident light wave of the binary diffraction grating is λ, the refractive index of the material of the binary diffraction grating is n, and the aperture of the microlens is p.

Through the above analysis and design, after obtaining the corresponding binary grating parameters, use the interference lithography machine to input the coded pattern and the required light control direction into the interference lithography machine to form a binary diffraction grating structure through interference lithography technology The preset pattern, and then use the electroforming process to transfer the preset pattern with a grating structure to the embossing roller.

A kind of three-dimensional dynamic grating sheet currently appearing is an optical imaging material prepared according to human visual differences and the principle of optical refraction. By. Although the existing three-dimensional grating sheet achieves a better viewing effect, the binary diffraction grating we designed can directional diffract the principal light of the pixel to the paraxial region of the microlens, which further reduces the image distortion during the imaging process. poor, thereby further improving the clarity of the display film.

Preferably, the display film can display a dynamic imaging effect. In this embodiment, a dynamic effect diagram as shown in FIG. 9 is given. FIG. 9 is a rotation dynamic change effect diagram of the embodiment of the present invention. It is a dynamic rotating display effect diagram that the observer can finally see on the microlenses with multiple elliptical structures. In this embodiment, when the observer observes the display film in a 360-degree direction, the ball composed of small rhombuses will rotate 360 degrees.

Preferably, this embodiment also provides a two-dimensional transformation effect diagram as shown in Figure 10. Figure 10 is a two-dimensional transformation effect diagram of the embodiment of the present invention. It can be changed into a small A and then changed into a big A, which is the effect of zooming in and out of the image; when the observer looks in the vertical direction, A can be changed into B and then changed into A, which is the transformation effect of the image. Its formation process is to combine a group of sequence diagrams in the horizontal direction and a group of sequence diagrams in the vertical direction to arrange the image pixels according to the specific microlens parameters and viewing requirements, and finally synthesize a coded diagram to achieve more accurate images for the observer. Rich and vivid viewing effects.

This embodiment provides a diagram of a manufacturing device for a display film as shown in FIG. 11 .

The first side and the second side of the high-temperature-resistant polyester thin PET film 1103 are covered with liquid curing glue, wherein the first side is opposite to the second side;

That is, in this production device, the glue roller 1102 is composed of 3 balls, the surfaces of which are in contact, one of which is located in the UV-curable glue pool 1101, and a connecting small ball in the middle, on which there is a slightly larger ball Ball, the surface of the ball is in contact with the PET film 1103, the glue roller 1102 rotates through the shaft, and the UV curing glue in the UV curing glue pool 1101 is applied to both sides of the PET film 1103;

forming a plurality of microlenses with an elliptical structure, wherein the plurality of microlenses are arranged in a matrix;

Embossing a plurality of microlenses with an elliptical structure on the first side of the PET film 1103, and embossing a preset pattern on the second side of the PET film 1103, wherein the The preset pattern is provided with a grating structure of a binary diffraction grating;

Preferably, embossing a plurality of microlenses with an elliptical structure on the first side of the PET film 1103, and embossing a preset on the second side of the PET film 1103 patterns, including:

Embossing a plurality of microlenses having an elliptical structure on the first side of the PET film 1103 by means of a roller 1104 wrapped with a nickel plate having a plurality of the microlens structures, and

A preset pattern is embossed on the second side of the PET film 1103 by a roller 1105 wrapped with a nickel plate having the preset pattern.

In this preparation device, the upper surface of the PET film 1103 is a roller 1104 with a plurality of elliptical microlenses, that is, the nickel plate with a plurality of said microlens structures is wrapped on the roller 1104, and the roller 1104 Embossing the PET film 1103 coated with UV curing in a viscous state, the lower surface of the PET film 1103 is a roller 1105 with a preset pattern, that is, the photoresist plate with a preset pattern is transferred to the On the nickel plate, the nickel plate is wrapped on the roller 1105, and the roller 1105 embosses the PET film 1103 coated with UV-curable glue in a viscous state;

By light irradiation, the plurality of microlenses with elliptical structures are formed on the first side of the PET film 1103, and the preset pattern is formed on the second side of the PET film 1103 .

Preferably, the plurality of microlenses having an elliptical structure are formed on the first side of the PET film 1103 by the irradiation of the light source, and on the second side of the PET film 1103 Forming the preset pattern includes:

Irradiated by an ultraviolet light source 1106, the plurality of microlenses having an elliptical structure are formed on the first side of the PET film 1103, and the pre-formed microlenses are formed on the second side of the PET film 1103. set pattern.

In this device, the two-layer structure is respectively transferred onto the PET film 1103 by irradiation of the ultraviolet light source 1106, and the film is completed.

The embodiment of the present invention introduces a structure and a preparation method of a display film, which realizes a high-definition, large viewing angle, and dynamic 3D display effect. Its key technology is the design of micro-lenses with elliptical structure and the design of preset patterns. Through the design of multiple elliptical microlenses combined with the directional diffraction properties of binary gratings to improve viewing clarity and viewing angles, and through different encoding methods combined with the imaging properties of microlenses, observers can experience rich and diverse dynamics display effect. This solution is to better improve and enhance the existing display film, and to better apply the existing microlens imaging technology and grating diffraction technology.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. There is no such actual relationship or order between them. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

Each embodiment in this specification is described in a related manner, the same and similar parts of each embodiment can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and for relevant parts, refer to part of the description of the method embodiment.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention are included in the protection scope of the present invention.

Claims (10)

1. A structure of an optical display film, characterized in that it comprises: A plurality of microlenses having an elliptical structure, wherein the plurality of microlenses are arranged in a matrix; A thin PET film of high temperature resistant polyester, the first side of the PET film is provided with the microlens, and the second side of the PET film is provided with a preset pattern, wherein the preset pattern is provided with binary In the grating structure of the diffraction grating, the first side is opposite to the second side. 2. the structure of optical display film as claimed in claim 1, is characterized in that, A predetermined pattern is embossed on the second side of the PET film. 3. the structure of optical display film as claimed in claim 1, is characterized in that, The preset pattern is engraved with a grating structure of a binary diffraction grating. 4. The structure of optical display film as claimed in claim 1, is characterized in that, The eccentricity of the microlens is e, wherein the e is: Where y is the height of the incident light on the aspheric surface, x is the rotational symmetry axis of the aspheric surface, is the radius of curvature of the vertex. 5. The structure of optical display film as claimed in claim 1 or 4, is characterized in that, The diffraction angle θ of the binary diffraction grating is: The period b of the binary diffraction grating is: The groove depth d of the binary diffraction grating is: Wherein, the wavelength of the incident light wave of the binary diffraction grating is λ, the refractive index of the material of the binary diffraction grating is n, and the aperture of the microlens is p. 6. A method for preparing a display film, characterized in that it is applied to the structure of the optical display film according to any one of claims 1 to 5, and the method for preparing the display film comprises: The first side and the second side of the high-temperature-resistant polyester thin PET film are covered with liquid curing glue, wherein the first side is opposite to the second side; forming a plurality of microlenses with an elliptical structure, wherein the plurality of microlenses are arranged in a matrix; embossing a plurality of microlenses with an elliptical structure on the first side of the PET film, and embossing a preset pattern on the second side of the PET film, wherein the preset a grating structure patterned with a binary diffraction grating; The plurality of microlenses having an elliptical structure are formed on the first side of the PET film and the preset pattern is formed on the second side of the PET film by irradiation of a light source. 7. The preparation method of display film as claimed in claim 6, is characterized in that, described forming a plurality of microlenses with elliptical structure, comprises: by formula form an elliptical structure; According to the elliptical structure, a plurality of microlenses with an elliptical structure are formed, wherein, y is the height of the incident light on the aspheric surface, x is the rotational symmetry axis of the aspheric surface, is the radius of curvature of the vertex, and e is the eccentricity of the curve. 8. the preparation method of display film as claimed in claim 7 is characterized in that, described by formula Form an elliptical structure consisting of: Through the aberration balancing algorithm, the formula The e in is adjusted to the default value; According to the preset value, a plurality of microlenses having an elliptical structure are formed. 9. The method for preparing a display film as claimed in claim 6, wherein said embossing a plurality of microlenses with an elliptical structure on said first side of said PET film, and said Embossing a predetermined pattern on the second side of the PET film, including: embossing a plurality of microlenses having an elliptical structure on the first side of the PET film by means of a roll having a plurality of microlenses wrapped in a nickel plate, and A preset pattern is embossed on the second side of the PET film by a roller wrapped with the preset pattern nickel plate. 10. The preparation method of display film as claimed in claim 6, it is characterized in that, described through the irradiation of light source, on the described first side of described PET film, form described a plurality of microlenses with elliptical structure, And forming the preset pattern on the second side of the PET film includes: The plurality of microlenses having an elliptical structure are formed on the first side of the PET film and the preset pattern is formed on the second side of the PET film by irradiation of an ultraviolet light source.