1. A method for producing an optical film, comprising the steps of:

(1) preparing film slurry;

(2) coating the film slurry on a base material to form a film slurry layer;

(3) hardening the film slurry layer to obtain the optical film;

wherein, modified zinc phosphate is added in the step of preparing the film slurry.

2. The method of claim 1, wherein in the step (2), the thin film paste is coated on the substrate to form a thin film paste layer having a thickness of 0.01 to 1 mm.

3. The method of claim 2, wherein in the step (2), the thin film paste is coated on the substrate to form a thin film paste layer having a thickness of 0.1 to 0.5 mm.

4. The method of manufacturing an optical film according to claim 1, wherein the curing treatment of the thin film paste layer is performed by ultraviolet irradiation in step (3).

5. The method for preparing the optical film according to claim 1, wherein the addition amount of the modified zinc phosphate is 1-10% of the amount of the film slurry; preferably, the adding mass of the modified zinc phosphate is 5-10% of the mass of the film slurry.

6. The method for producing an optical film according to claim 1, wherein the modified zinc phosphate is produced by a method comprising the steps of:

adding zinc phosphate into water, then adding silicon dioxide and borax, adjusting the pH value to 4.0-5.0, stirring uniformly, aging for 24-48 h, filtering to obtain a solid, drying, and grinding uniformly to obtain the modified zinc phosphate;

wherein the mass ratio of the zinc phosphate to the silicon dioxide to the borax to the water is 20-40: 5-10: 1-5: 100.

7. The method of claim 6, wherein the modified zinc phosphate is obtained by adding zinc phosphate to water, adding silica and borax, adjusting the pH to 4.5, stirring uniformly, aging for 36 hours, filtering to obtain a solid, drying, and grinding uniformly.

8. The method of claim 6, wherein the mass ratio of zinc phosphate, silica, borax, and water is 30:7:3: 100.

9. An optical film produced by the production method according to any one of claims 1 to 8.

10. A backlight module comprising a light guide plate, wherein the optical film according to claim 9 is disposed on the light guide plate.

Background

The backlight module is a component of the display, and the light guide plate in the backlight module is used for guiding the scattering direction of light generated by the light source and ensuring the brightness of the light-emitting surface to be uniform. The light guide plate generally comprises a transparent substrate and a light guide material positioned on the transparent substrate, but the absorption rate of the general light guide material to visible light is high, so that the light transmittance of the visible light is low; therefore, the brightness of the light passing through the light guide material is reduced.

The problem that the existing light guide material is high in visible light absorption rate and low in light penetration rate of visible light, and further brightness is reduced is solved; in the patent CN102401926B, a light guide material layer containing light guide ink is coated on a transparent substrate of a light guide plate, and the absorption rate of the light guide ink to visible light is low, and when the thickness of the light guide ink is 500 μm, the light guide ink has a light transmittance of more than 95% to visible light, thereby ensuring that the brightness of the visible light is not reduced after passing through the light guide material layer. Although the invention patent CN102401926B can improve the light transmittance of the light guide plate to visible light by coating a layer of light guide material containing light guide ink on the substrate, the complexity of the process is undoubtedly improved in the actual processing and production process. If an optical film capable of ensuring that the light guide plate has higher visible light transmittance is developed, the optical film is used for replacing the light guide material layer containing the light guide ink disclosed in the invention patent CN102401926B, and the optical film has important significance for simplifying the production process of the light guide plate.

However, researches have found that the light guide plate prepared by adhering a general optical film to a transparent substrate of the light guide plate still has low light transmittance to visible light, and also causes the problem that the brightness of light passing through the light guide plate is reduced; for example, patent CN 102471508B discloses an acrylic film which can be applied to various industrial sheets such as protective films for various semiconductor processes, optical adhesive or bonding products, electronic component adhesive or bonding products, and the like, or laminated products having a multilayer structure, and can exhibit excellent effects; but the transparent substrate of the light guide plate is directly applied, and the visible light transmittance is low. Therefore, it is a technical problem in the art to develop a new optical film capable of improving the transmittance of the light guide plate to visible light.

Disclosure of Invention

In order to solve at least one technical problem in the prior art; the invention firstly provides a preparation method of an optical film; the optical film prepared by the method is applied to the light guide plate, so that the light guide plate has high visible light transmittance.

The technical problem to be solved by the invention is realized by the following technical scheme:

a method for producing an optical film, comprising the steps of:

(1) preparing film slurry;

(2) coating the film slurry on a base material to form a film slurry layer;

(3) hardening the film slurry layer to obtain the optical film;

wherein, modified zinc phosphate is added in the step of preparing the film slurry.

In order to solve the technical problems of the invention, the inventor adds a large amount of light guide substances in the preparation process of the optical film so as to obtain the optical film capable of improving the visible light transmittance of the light guide plate; but the effect is not ideal; the optical film prepared by adding the conventional light guide substance cannot effectively improve the visible light transmittance of the light guide plate. Through a large number of experiments, the inventor surprisingly discovers that the optical film prepared by adding the modified zinc phosphate in the step of preparing the film slurry can ensure that the light guide plate has higher visible light transmittance when the optical film is attached to the light guide plate; therefore, the problem of brightness reduction caused by light passing through the light guide plate can be solved.

Preferably, in the step (2), the film slurry is coated on the substrate to form a film slurry layer with a thickness of 0.01-1 mm.

Further preferably, in the step (2), the film slurry is coated on the substrate to form a film slurry layer with a thickness of 0.1-0.5 mm.

Most preferably, the film slurry is coated onto the substrate to form a 0.5mm thick film slurry layer.

Preferably, the film paste layer is hardened by ultraviolet irradiation in step (3).

Further preferably, 50-150 mW/cm is adopted in the step (3)²The ultraviolet irradiation is carried out for 5-20 min, and the film slurry layer is hardened.

Most preferably, 100mW/cm is used in step (3)²The film slurry layer was cured by ultraviolet irradiation for 10 min.

Preferably, the specific method for preparing the film slurry is as follows: and (2) mixing 80-120 parts by weight of butyl acrylate and 40-60 parts by weight of methyl methacrylate, uniformly stirring, adding 4-10 parts by weight of photoinitiator, and continuously uniformly stirring to obtain the film slurry.

Most preferably, the specific method of preparing the thin film paste is: and (2) mixing 100 parts by weight of butyl acrylate and 50 parts by weight of methyl methacrylate, uniformly stirring, adding 5 parts by weight of photoinitiator, and continuously uniformly stirring to obtain the film slurry.

Preferably, the adding mass of the modified zinc phosphate is 1-10% of the mass of the film slurry.

More preferably, the adding mass of the modified zinc phosphate is 5-10% of the mass of the film slurry.

Preferably, the modified zinc phosphate is prepared by a method comprising the following steps:

adding zinc phosphate into water, then adding silicon dioxide and borax, adjusting the pH value to 4.0-5.0, stirring uniformly, aging for 24-48 h, filtering to obtain a solid, drying, and grinding uniformly to obtain the modified zinc phosphate;

wherein the mass ratio of the zinc phosphate to the silicon dioxide to the borax to the water is 20-40: 5-10: 1-5: 100.

Preferably, the zinc phosphate is added into water, then silicon dioxide and borax are added, the pH value is adjusted to 4.5, the mixture is aged for 36 hours after being stirred uniformly, solid is filtered and taken out, and the modified zinc phosphate is obtained after drying and grinding uniformly.

Preferably, the mass ratio of the zinc phosphate, the silica, the borax and the water is 30:7:3: 100.

The inventor researches and shows that the modification method of modified zinc phosphate plays a decisive role in preparing an optical film capable of improving the visible light transmittance of a light guide plate.

In the preparation process of the optical film, only modified zinc phosphate obtained by modifying zinc phosphate by silicon dioxide and borax is added, so that the light guide plate adhered with the optical film has higher visible light transmittance; in the preparation process of the optical film, modified zinc phosphate obtained by modifying zinc phosphate by other substances is added, so that the light guide plate adhered with the optical film cannot have high visible light transmittance.

Further preferably, a composition consisting of modified zinc phosphate and zinc stearate in a mass ratio of 3-5: 1 is added in the step of preparing the film slurry.

Most preferably, a composition consisting of modified zinc phosphate and zinc stearate in a mass ratio of 4:1 is also added in the step of preparing the film slurry.

The inventor further researches and shows that the light transmittance of the light guide plate stuck with the optical film to visible light can be further improved by adding the modified zinc phosphate and the zinc stearate into the optical film together; compared with the optical film which is added with modified zinc phosphate or zinc stearate separately, the optical film has higher light transmittance of visible light. This shows that the optical film can be added with zinc phosphate and zinc stearate to improve the light transmittance of the light guide plate stuck with the optical film to visible light.

The invention also provides an optical film prepared by the preparation method.

The invention also provides a backlight module which comprises a light guide plate, wherein the optical film is arranged on the light guide plate.

Has the advantages that: the invention provides a brand-new preparation method of an optical film; the optical film prepared by the method is pasted on the light guide plate, so that the light guide plate has higher visible light transmittance, and the problem of brightness reduction of light after passing through the light guide plate is further solved; furthermore, the backlight module adopts the light guide plate comprising the optical film, and the problem of brightness reduction of a display can be effectively solved.

Detailed Description

The present invention is further explained below with reference to specific examples, which are not intended to limit the present invention in any way.

Example 1 preparation of optical film

(1) Preparing film slurry: mixing 100 parts by weight of butyl acrylate and 50 parts by weight of methyl methacrylate, uniformly stirring, adding 5 parts by weight of photoinitiator TPO and 10 parts by weight of modified zinc phosphate, and continuously uniformly stirring to obtain the film slurry;

(2) coating the film slurry on a PET substrate to form a film slurry layer with the thickness of 0.5 mm;

(3) using 100mW/cm²Irradiating the film slurry layer for 10min, and hardening the film slurry layer to obtain the optical film;

the modified zinc phosphate in the step (1) is prepared by the following method: adding zinc phosphate into deionized water, then adding silicon dioxide and borax, adjusting the pH value to 4.5, stirring uniformly, aging for 36h, filtering to obtain a solid, drying, and grinding uniformly to obtain the modified zinc phosphate; wherein the mass ratio of the zinc phosphate to the silicon dioxide to the borax to the deionized water is 30:7:3: 100.

Example 2 preparation of optical film

(1) Preparing film slurry: mixing 80 parts by weight of butyl acrylate and 60 parts by weight of methyl methacrylate, uniformly stirring, adding 4 parts by weight of photoinitiator TPO and 8 parts by weight of modified zinc phosphate, and continuously uniformly stirring to obtain the film slurry;

(2) coating the film slurry on a PET substrate to form a film slurry layer with the thickness of 0.1 mm;

(3) using 50mW/cm²Irradiating the film slurry layer for 20min, and hardening the film slurry layer to obtain the optical film;

the modified zinc phosphate in the step (1) is prepared by the following method: adding zinc phosphate into deionized water, then adding silicon dioxide and borax, adjusting the pH value to 4.0, stirring uniformly, aging for 48h, filtering to obtain a solid, drying, and grinding uniformly to obtain the modified zinc phosphate; wherein the mass ratio of the zinc phosphate to the silicon dioxide to the borax to the deionized water is 20:5:1: 100.

Example 3 preparation of optical film

(1) Preparing film slurry: mixing 120 parts by weight of butyl acrylate and 40 parts by weight of methyl methacrylate, uniformly stirring, adding 10 parts by weight of photoinitiator TPO and 15 parts by weight of modified zinc phosphate, and continuously uniformly stirring to obtain the film slurry;

(2) coating the film slurry on a PET substrate to form a film slurry layer with the thickness of 0.3 mm;

(3) using 150mW/cm²Irradiating the film slurry layer for 5min, and hardening the film slurry layer to obtain the optical film;

the modified zinc phosphate in the step (1) is prepared by the following method: adding zinc phosphate into deionized water, then adding silicon dioxide and borax, adjusting the pH value to 5.0, stirring uniformly, aging for 24h, filtering to obtain a solid, drying, and grinding uniformly to obtain the modified zinc phosphate; wherein the mass ratio of the zinc phosphate to the silicon dioxide to the borax to the deionized water is 40:10:3: 100.

EXAMPLE 4 preparation of optical film

(1) Preparing film slurry: mixing 100 parts by weight of butyl acrylate and 50 parts by weight of methyl methacrylate, uniformly stirring, adding 5 parts by weight of photoinitiator TPO, 8 parts by weight of modified zinc phosphate and 2 parts by weight of zinc stearate, and continuously uniformly stirring to obtain the film slurry;

(2) coating the film slurry on a PET substrate to form a film slurry layer with the thickness of 0.5 mm;

(3) using 100mW/cm²Irradiating the film slurry layer for 10min, and hardening the film slurry layer to obtain the optical film;

the modified zinc phosphate in the step (1) is prepared by the following method: adding zinc phosphate into deionized water, then adding silicon dioxide and borax, adjusting the pH value to 4.5, stirring uniformly, aging for 36h, filtering to obtain a solid, drying, and grinding uniformly to obtain the modified zinc phosphate; wherein the mass ratio of the zinc phosphate to the silicon dioxide to the borax to the deionized water is 30:7:3: 100.

Example 4 is different from example 1 in that example 4 adds zinc phosphate modifier and zinc stearate during the preparation of the thin film paste.

Comparative example 1 preparation of optical film

(1) Preparing film slurry: mixing 100 parts by weight of butyl acrylate and 50 parts by weight of methyl methacrylate, uniformly stirring, adding 5 parts by weight of photoinitiator TPO, and continuously uniformly stirring to obtain the film slurry;

(2) coating the film slurry on a PET substrate to form a film slurry layer with the thickness of 0.5 mm;

(3) using 100mW/cm²And (3) irradiating the film slurry layer for 10min, and hardening the film slurry layer to obtain the optical film.

Comparative example 1 is different from example 1 in that the optical film of comparative example 1 is a conventional acrylic film to which modified zinc phosphate is not added.

Comparative example 2 preparation of optical film

(1) Preparing film slurry: mixing 100 parts by weight of butyl acrylate and 50 parts by weight of methyl methacrylate, uniformly stirring, adding 5 parts by weight of photoinitiator TPO and 10 parts by weight of zinc phosphate, and continuously and uniformly stirring to obtain the film slurry;

(2) coating the film slurry on a PET substrate to form a film slurry layer with the thickness of 0.5 mm;

(3) using 100mW/cm²And (3) irradiating the film slurry layer for 10min, and hardening the film slurry layer to obtain the optical film.

Comparative example 2 is different from example 1 in that zinc phosphate was added to the optical film of comparative example 2, and modified zinc phosphate prepared by the brand new method of the present invention was added to the optical film of example 1.

Comparative example 3 preparation of optical film

(1) Preparing film slurry: mixing 100 parts by weight of butyl acrylate and 50 parts by weight of methyl methacrylate, uniformly stirring, adding 5 parts by weight of photoinitiator TPO and 10 parts by weight of zinc stearate, and continuously uniformly stirring to obtain the film slurry;

(2) coating the film slurry on a PET substrate to form a film slurry layer with the thickness of 0.5 mm;

(3) using 100mW/cm²Ultraviolet irradiation for 10min, and applying to the thin film slurryAnd hardening the layer to obtain the optical film.

Comparative example 3 is different from example 1 in that zinc stearate was added to the optical film of comparative example 3, and modified zinc phosphate prepared by the brand new method of the present invention was added to the optical film of example 1.

Comparative example 4 preparation of optical film

(1) Preparing film slurry: mixing 100 parts by weight of butyl acrylate and 50 parts by weight of methyl methacrylate, uniformly stirring, adding 5 parts by weight of photoinitiator TPO and 10 parts by weight of silicon dioxide, and continuously uniformly stirring to obtain the film slurry;

(2) coating the film slurry on a PET substrate to form a film slurry layer with the thickness of 0.5 mm;

(3) using 100mW/cm²Irradiating the film slurry layer for 10min, and hardening the film slurry layer to obtain the optical film;

comparative example 4 is different from example 1 in that silica is added to the optical film of comparative example 4, and modified zinc phosphate prepared by the brand new method of the present invention is added to the optical film of example 1.

Comparative example 5 preparation of optical film

(1) Preparing film slurry: mixing 100 parts by weight of butyl acrylate and 50 parts by weight of methyl methacrylate, uniformly stirring, adding 5 parts by weight of photoinitiator TPO and 10 parts by weight of modified zinc phosphate, and continuously uniformly stirring to obtain the film slurry;

(2) coating the film slurry on a PET substrate to form a film slurry layer with the thickness of 0.5 mm;

(3) using 100mW/cm²Irradiating the film slurry layer for 10min, and hardening the film slurry layer to obtain the optical film;

the modified zinc phosphate in the step (1) is prepared by the following method: adding zinc phosphate into deionized water, then adding silicon dioxide, adjusting the pH value to 4.5, uniformly stirring, aging for 36h, filtering to obtain a solid, drying, and uniformly grinding to obtain the modified zinc phosphate; wherein the mass ratio of the zinc phosphate to the silicon dioxide to the deionized water is 30:10: 100.

Comparative example 5 is different from example 1 in that the raw material for modifying zinc phosphate in comparative example 5 is different, and comparative example 5 prepares modified zinc phosphate by modifying zinc phosphate with silica only by the method described in this invention; while example 1 is a modified zinc phosphate prepared by modifying silica and borax by the method of the invention.

Comparative example 6 preparation of optical film

(1) Preparing film slurry: mixing 100 parts by weight of butyl acrylate and 50 parts by weight of methyl methacrylate, uniformly stirring, adding 5 parts by weight of photoinitiator TPO and 10 parts by weight of modified zinc phosphate, and continuously uniformly stirring to obtain the film slurry;

(2) coating the film slurry on a PET substrate to form a film slurry layer with the thickness of 0.5 mm;

(3) using 100mW/cm²Irradiating the film slurry layer for 10min, and hardening the film slurry layer to obtain the optical film;

the modified zinc phosphate in the step (1) is prepared by the following method: adding zinc phosphate into deionized water, then adding borax, adjusting the pH value to 4.5, stirring uniformly, aging for 36h, filtering to obtain a solid, drying, and grinding uniformly to obtain the modified zinc phosphate; wherein the mass ratio of the zinc phosphate to the borax to the deionized water is 30:10: 100.

Comparative example 6 is different from example 1 in that the raw material for modifying zinc phosphate in comparative example 6 is different, and comparative example 5 is a method for preparing modified zinc phosphate by modifying zinc phosphate with borax only by the method described herein; while example 1 is a modified zinc phosphate prepared by modifying silica and borax by the method of the invention.

Comparative example 7 preparation of optical film

(1) Preparing film slurry: mixing 100 parts by weight of butyl acrylate and 50 parts by weight of methyl methacrylate, uniformly stirring, adding 5 parts by weight of photoinitiator TPO and 10 parts by weight of modified zinc phosphate, and continuously uniformly stirring to obtain the film slurry;

(2) coating the film slurry on a PET substrate to form a film slurry layer with the thickness of 0.5 mm;

(3) using 100mW/cm²Irradiating the film slurry layer for 10min, and hardening the film slurry layer to obtain the optical film;

the modified zinc phosphate in the step (1) is prepared by the following method: and mixing zinc phosphate, silicon dioxide and borax according to the mass ratio of 30:7:3, and uniformly grinding to obtain the modified zinc phosphate.

Comparative example 7 is different from example 1 in that the modification method of modifying zinc phosphate in comparative example 7 is different; comparative example 7 is only a simple process of mixing zinc phosphate, silica and borax to obtain modified zinc phosphate; in example 1, zinc phosphate, silica and borax were added to deionized water and aged to obtain modified zinc phosphate.

Comparative example 8 preparation of optical film

(1) Preparing film slurry: mixing 100 parts by weight of butyl acrylate and 50 parts by weight of methyl methacrylate, uniformly stirring, adding 5 parts by weight of photoinitiator TPO, 8 parts by weight of modified zinc phosphate and 2 parts by weight of silicon dioxide, and continuously uniformly stirring to obtain the film slurry;

(2) coating the film slurry on a PET substrate to form a film slurry layer with the thickness of 0.5 mm;

(3) using 100mW/cm²Irradiating the film slurry layer for 10min, and hardening the film slurry layer to obtain the optical film;

the modified zinc phosphate in the step (1) is prepared by the following method: adding zinc phosphate into deionized water, then adding silicon dioxide and borax, adjusting the pH value to 4.5, stirring uniformly, aging for 36h, filtering to obtain a solid, drying, and grinding uniformly to obtain the modified zinc phosphate; wherein the mass ratio of the zinc phosphate to the silicon dioxide to the borax to the deionized water is 30:7:3: 100.

Example 4 is different from comparative example 8 in that example 4 added zinc phosphate modifier and zinc stearate during the preparation of the thin film paste; in contrast, comparative example 8 was prepared by adding modified zinc phosphate and silica during the preparation of the film slurry.

Attaching the optical films prepared in examples 1 to 4 and comparative examples 1 to 8 to a transparent substrate of a light guide plate to form the light guide plate; testing the influence of each optical film on the light transmittance (light transmittance) of the light guide plate at 400nm, 600nm and 780nm by using a light transmittance tester; specific results are shown in table 1.

TABLE 1 influence of optical films on light transmittance of light guide plate

As can be seen from the data in table 1, comparative example 1, which employs a conventional acrylic film attached to a light guide plate, has a low light transmittance; especially, the transmittance of the light with the wavelength of 400nm is extremely low, and is only 52.3 percent; this indicates that the light transmittance of the light guide plate cannot be improved by attaching a conventional acrylic film to the light guide plate.

As can be seen from the experimental data of the light transmittance of comparative examples 2 to 4, the optical film prepared by adding conventional substances such as zinc phosphate, zinc stearate or silicon dioxide to the conventional acrylic film cannot effectively improve the light transmittance of 400 to 780nm of the light guide plate compared with the optical film without adding the substances in comparative example 1; the requirement of the light guide plate with high penetration rate cannot be met.

As can be seen from the experimental data of the light transmittance of the examples 1 to 3, the light transmittance of the acrylic film added with the modified zinc phosphate prepared by the brand-new method is greatly improved compared with that of the comparative examples 1 to 4; wherein the magnitude of the increase in transmittance for light of 400nm is greatest; the transmittance of the material to 400nm light is more than 80%, the transmittance of the material to 600nm light is more than 88%, and the transmittance of the material to 780nm light is more than 95%, which are greatly higher than those of comparative examples 1-4. The optical film prepared by adding the modified zinc phosphate of the invention into the acrylic film can greatly improve the light transmittance of the light guide plate in the range of 400-780 nm compared with unmodified zinc phosphate, conventional zinc stearate or silicon dioxide; especially, the transmittance of the light guide plate to 400nm light can be greatly improved; the remarkable technical effect is achieved.

As can be seen from the experimental data of light transmittance in example 4, the optical film prepared by adding the modified zinc phosphate and zinc stearate prepared by the novel method of the invention into the acrylic film has a light transmittance to the light guide plate higher than that of the optical film prepared by adding the modified zinc phosphate alone in example 1; the transmittance of the material to 400nm light reaches 98.2%, the transmittance to 600nm light reaches 99.5%, and the transmittance to 780nm light reaches 100%; compared with embodiment 1, the light transmission effect is further greatly improved, and a more excellent light transmission effect is obtained. The modified zinc phosphate and the zinc stearate can be combined to synergistically improve the transmittance of the light guide plate stuck with the optical film to light in the range of 400-780 nm.

As can be seen from the experimental data of light transmission rates of comparative examples 5 and 6, the light transmission rates of comparative examples 5 and 6 are much smaller than those of example 1, which indicates that: the transmittance of the light guide plate to light within the range of 400-780 nm can be greatly improved only by adding an optical film prepared from modified zinc phosphate obtained by modifying zinc phosphate by silicon dioxide and borax; the optical film prepared by only adding the modified zinc phosphate obtained by modifying zinc phosphate by one component of silicon dioxide or borax or other components cannot greatly improve the transmittance of the light guide plate to light within the range of 400-780 nm.

As can be seen from the experimental data of light transmittance of comparative example 7, the light transmittance of comparative example 7 is much smaller than that of example 1, which shows that: the optical film prepared by simply mixing zinc phosphate, silicon dioxide and borax to obtain modified zinc phosphate cannot effectively improve the transmittance of the light guide plate to light within the range of 400-780 nm. The method of the invention is adopted to add zinc phosphate, silicon dioxide and borax into deionized water, and the modified zinc phosphate is prepared after aging. The modified zinc phosphate prepared by the method provided by the invention is used for preparing an optical film, so that the transmittance of a light guide plate to light within the range of 400-780 nm can be greatly improved.

As can be seen from the experimental data of light transmittance of comparative example 8, the light transmittance of comparative example 8 is smaller than that of examples 1 and 4; therefore, compared with the embodiment 1, the transmittance of the light guide plate to light in the range of 400-780 nm is reduced after the silicon dioxide is added; the optical film prepared by adding the modified zinc phosphate and the zinc stearate can synergistically improve the transmittance of the light guide plate to light within the range of 400-780 nm; the optical film prepared by adding modified zinc phosphate and silicon dioxide or adding the combination of modified zinc phosphate and other substances cannot synergistically improve the transmittance of the light guide plate to light within the range of 400-780 nm.