TWI762929B - Optical flexible cover structure - Google Patents

Abstract

The present invention is an optically flexible cover plate structure, which comprises: a transparent plastic substrate layer, the thickness of the transparent plastic substrate layer is between 15-100 μm; at least two hard coatings, wherein the thickness of the first hard coating is 3-100 μm 8 μm, which is located on one surface of the transparent plastic substrate layer; wherein the thickness of the second hard coating is 1.5-3 μm, which is located on the other surface of the first hard coating; the thickness of the first hard coating Greater than the second hard coating, the light transmittance of each single hard coating is between 85% and 95% and the refractive index difference with the adjacent hard coating layer is at least 0.5% or more; the refractive index of the hard coating layer is between 1.3 and 1.6; the The optical flexible cover structure is characterized in that the transparent plastic substrate layer and at least two hard coatings are stacked and combined to cause the optical flexible cover structure to cause total internal reflection of light, so that the polymer optically flexible cover structure has a surface close to that of glass. Appearance and anti-scratch and bending properties.

Description

Optical flexible cover structure

The present invention relates to the technical field of optical film display, in particular to a cover plate for a flexible display screen substrate.

The cover material of the flexible display screen substrate is mostly composed of rigid glass or flexible polymer and functional layer. Among them, the cover plate of the glass display substrate cannot be bent or bent with a large curvature, which does not meet the needs of future foldable display devices. Compared with the cover plate made of glass material, polyimide materials with high surface hardness and high toughness become flexible display materials. The preferred polymer material for the screen cover, but it needs a surface coating to improve the hardness. In the past research, it was found that polyimide has the disadvantages of insufficient hardness and thick thickness as a cover plate. In addition, the cover plate with polarizing function in the display module is made of optical glue and the upper polarizer. This design will cause the overall thickness to be thicker, and because of the existence of a flexible optical glue layer, it will cause cover The hardness of the board decreases.

The prior art is directed to the research on the polyimide precursor composition of flexible substrates, such as the Republic of China Patent Publication No. I595025, which is a polyimide precursor composition for producing flexible substrates for optoelectronic components. The polyimide precursor composition includes a polyimide precursor derived from a structure of a diamine or an acid dianhydride. Also disclosed is a polyimide film produced from the polyimide precursor composition. Polyimide film by A precursor composition is applied to a substrate and the composition is cured to obtain. Applications of the compositions and films include their use in laminates, photovoltaic elements or flexible displays. The prior art studies on a siloxane resin for window film or a mixture thereof, as disclosed in Patent Publication Nos. I589645 and I580742 of the Republic of China, a composition for a window film, comprising: a siloxane resin or a mixture thereof, wherein crosslinkable Functional groups include epoxy, epoxy-containing groups, glycidyl groups, glycidyl-containing groups, glycidyloxy groups, glycidyloxy-containing groups, oxetanyl groups, or oxetane-containing groups base group. The prior art is directed to the research on substrate components coated with simple cleaning coatings. For example, as disclosed in Patent Publication Nos. I455899 and I455900 of the Republic of China, a substrate component for coating simple cleaning coatings, wherein the substrate components can improve the simple cleaning coating. Hydrophobicity, oleophobicity and durability of the layer. The substrate element comprises a carrier material composed of glass or glass-ceramic and an anti-reflection coating composed of one or at least two layers, wherein the one or the uppermost layer of the at least two layers is an adhesion promoter layer, the adhesion promoter The adhesion promoter layer can interact with the easy-clean coating, and the adhesion promoter layer contains mixed oxides, especially mixed oxides of silicon.

The prior art is aimed at improving the overall hardness of the flexible display screen cover plate, as disclosed in the Chinese Mainland Patent Publication No. CN110576664A, a flexible display screen cover plate, which relates to the technical field of optical films. The flexible display cover plate includes: a transparent aromatic polyamide substrate; a polysilazane layer, which is arranged on one side of the transparent aromatic polyamide substrate; and a polarizing layer, which is arranged on the aromatic polyamide substrate. on the amide substrate and on the other side opposite to the polysilazane layer; a hardening layer is provided on the polarizing layer and on the other side opposite to the transparent aromatic polyamide substrate. By directly preparing the polarizing layer on the transparent aromatic polyamide substrate, the overall thickness of the flexible display cover is reduced, and the overall hardness of the flexible display cover is greatly improved.

The prior art is aimed at improving the hardness and bending resistance of the flexible display cover plate. Thin glass layers and substrates, ultra-thin glass layers for sticking Attached to the flexible display, the ultra-thin glass layer has bendability; the substrate is formed on the ultra-thin glass layer, and the substrate is used to improve the hardness of the flexible cover plate. Due to the ultra-thin properties of the ultra-thin glass layer, the glass layer has good bending properties, and the substrate does not affect the bending properties of the flexible cover plate, while improving the hardness of the flexible cover plate, so that the ultra-thin glass layer has good bending properties. The flexible cover plate composed of the thin glass layer and the base material has good bending properties and also has properties such as hardness and drop resistance. Another example disclosed in Mainland China Patent Publication No. CN110602274A is a flexible display screen cover, which relates to the technical field of optical films. The flexible display cover plate includes: a transparent aromatic polyamide substrate; a polysilazane layer, which is arranged on one side of the transparent aromatic polyamide substrate; a protective layer, which is arranged on the polysilicon nitride The alkane layer is on one side of the transparent aromatic polyamide substrate. In this study, aromatic polyamides were used as substrates to improve the hardness and bending resistance of traditional flexible display cover sheets.

The creator of this creation has been working in the display industry for many years, and he is well aware that the hardness, curvature and similarity of the glass appearance of the cover plate of the flexible display substrate still have deficiencies that need to be solved. . The present invention is an optically flexible cover plate structure, which comprises: a transparent plastic substrate layer, which is made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), cycloolefin It is composed of polymer (Cyclo-olefin polymer), polyamide, polyimide or polyaramide material, the thickness of the transparent plastic substrate layer is between 15~100μm; at least two hard coatings, of which the first A hard coating with a thickness of 3-8 μm located on one surface of the transparent plastic substrate layer; a second hard coating with a thickness of 1.5-3 μm located on the other surface of the first hard coating; The thickness of a hard coat layer is greater than that of the second hard coat layer, the transmittance of each single hard coat layer is between 85% and 95%, and the difference in refractive index with the adjacent hard coat layer is at least 0.5% or more; wherein, the hard coat layer is composed of At least one silicone resin, polysilazane resin, epoxy resin, acrylic resin, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), cycloolefin polymer Cyclo-olefin polymer, polyamide, polyimide or polyarylene A polymer material of amine (Polyaramide), which is mixed with 1 to 10% by weight of aluminum, tin, magnesium, phosphorus, cerium, zirconium, titanium, cesium, barium, strontium, niobium, zinc, relative to the weight of the polymer material It is composed of at least one oxide of boron and/or silicon oxide mixed with magnesium fluoride, and the refractive index of the hard coating is between 1.3 and 1.6; the optical flexible cover structure is characterized in that the transparent plastic substrate layer Stacked and combined with at least two hard coatings to cause the optically flexible cover plate structure to cause total internal reflection of light, so that the polymer optically flexible cover plate structure has an appearance close to that of glass, and has anti-scratch and bending properties. Wherein, the total light transmittance of the transparent plastic substrate layer (within the wavelength range of 380-780 nm)≧90%. The haze of the transparent plastic substrate layer is less than 1%. The refractive index of the transparent plastic substrate layer is between 1.6 and 1.7. The refractive index of the first hard coat layer in the at least two hard coat layers is between 1.3 and 1.4. The refractive index of the second hard coat layer in the at least two hard coat layers is between 1.5 and 1.6. The at least two hard coating layers are stacked on each other, and the total thickness is between 4.5-20 μm. The hard coating layer has a progressive refractive index arrangement and is superimposed on a surface of the transparent plastic substrate layer. The bending resistance of the optically flexible cover structure is in the in-folding direction (In-folding): the bending radius R is 1.5mm, up to 200,000 times, and the out-folding direction (Out-folding): the bending radius R is 3mm, up to 200,000 times. The bending degree of the optically flexible cover structure is less than or equal to 5mm. The hardness of the optically flexible cover structure is ≧5H. The present invention has a thick coating with better anti-scratch ability, and controls the optical flexible cover plate structure to cause the internal total reflection of light. It is different from the vacuum coating technology of the prior art in the past, and it is different, novel, advanced and practical. The benefits are correct. Regarding the techniques, means and effects used in this creation, a preferred embodiment is given and explained in detail in conjunction with the drawings. It is believed that the above-mentioned purposes, structures and features of this creation can be used to gain an in-depth and specific understanding. .

101: Transparent plastic substrate layer

201: Hard Coating

2011: First hard coat

2012: Second hard coat

2013: Third hard coat

2014: Fourth hard coat

Figure 1 shows the structure of the optical flexible cover plate of this creation.

Figure 2 is a structural diagram of another optical flexible cover plate of the present invention.

The following describes the implementation of the present invention through specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. This creation can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the spirit of this creation.

First of all, please refer to FIG. 1, which shows the structure of the optical flexible cover plate of the present invention. It shows that the present invention is an optical flexible cover plate structure, which includes: a transparent plastic substrate layer 101, which is made of polyethylene terephthalate. Diol ester (PET), polyethylene naphthalate (PEN), cyclo-olefin polymer (Cyclo-olefin polymer), polyamide, polyimide or polyaramide (Polyaramide) material, The thickness of the transparent plastic substrate layer 101 ranges from 15 to 100 μm, and the thickness data of this creation is measured according to ASTM D3652 standard; at least two hard coat layers 201 , wherein the thickness of the first hard coat layer 2011 is 3 to 8 μm, which is located on the transparent plastic layer. on one surface of the substrate layer 101; wherein the thickness of the second hard coating layer 2012 is 1.5-3 μm, which is located on the other surface of the first hard coating layer 2011; the thickness of the first hard coating layer 2011 is greater than that of the second hard coating layer 2011 Coating 2012, the thickness of the first hard coating layer 2011 is thicker to resist scratching and bending external force, and the second hard coating layer 2012 with a thinner thickness covers the first hard coating layer 2011 to strengthen the first hard coating layer 2011 External horizontal stress to enhance scratch resistance with distributed stress resistance. In terms of optical properties, the transmittance of each single hard coating layer 201 is between 85% and 95% and the refractive index difference with the adjacent hard coating layer 201 is at least 0.5% or more; wherein, the hard coating layer 201 is made of at least one siloxane resin, Polysilazane resin, epoxy resin, acrylic resin, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), cyclo-olefin polymer (Cyclo-olefin polymer) , polyamide, polyimide or polyaramide (Polyaramide) polymer material, and relative to the weight of the polymer material blended with 1 to 10% by weight of aluminum, tin, magnesium, phosphorus, cerium, The hard coat layer 201 is composed of at least one oxide of zirconium, titanium, cesium, barium, strontium, niobium, zinc and boron and/or silicon oxide mixed with magnesium fluoride. The refractive index of the hard coat layer 201 is between 1.3 and 1.6; The optical flexible cover structure is characterized in that the transparent plastic substrate layer 101 and at least two hard coatings 201 are stacked and combined to cause the optical flexible cover structure to cause total internal reflection of light, so that the polymer optical flexible cover structure has close to The appearance of the glass, and it is resistant to scratches and bending. Wherein, the total light transmittance of the transparent plastic substrate layer 101 (within the wavelength range of 380-780 nm)≧90%, which is measured by the JIS K7361 test method. The haze of the transparent plastic substrate layer 101 is less than 1%, which is measured according to the JIS K7136 test standard. The refractive index of the transparent plastic substrate layer 101 ranges from 1.6 to 1.7. The refractive index of the first hard coating layer 2011 of the at least two hard coating layers 201 is between 1.3 and 1.4. The refractive index of the second hard coating layer 2012 in the at least two hard coating layers 201 is between 1.5 and 1.6. The at least two hard coat layers 201 are stacked on each other with a total thickness of 4.5-20 μm. The hard coat layers 201 have a progressive refractive index arrangement and are superimposed on a surface of the transparent plastic substrate layer 101 . The bending resistance of the optically flexible cover plate structure In-folding direction (In-folding): bending radius R is 1.5mm, 200,000 times, Out-folding direction: bending radius R is 3mm, 200,000 times Second, the test is width: 14.2 cm, length: 10.7 cm, speed: 60 rpm, and the bending times are measured, and the surface cracking condition is observed. The curvature of the optically flexible cover structure is ≦5mm, and the size of the test sample is 200×200mm. The hardness of the optically flexible cover plate structure is ≧5H, and the test is carried out with a pencil hardness tester under a load of 750gf/cm ² and a speed of 60mm/min.

This creation overcomes the fact that the traditional coating method cannot be applied to the optical film of the folding cover. The main reason is that the thickness of the metal oxide coating is very thin, and it is not resistant to surface characteristics such as bending and scratching hardness. Therefore, the folding cover The anti-reflection (AR) function is mainly used to adjust the refractive index n of the first hard coat layer 2011 and the second hard coat layer 2012 in the double-layer coating between 1.3 and 1.6, and the adjacent hard coat layers The refractive index difference of 201 is at least 0.5% or more to achieve the purpose of reducing reflectivity. The anti-reflection principle is the combination of hard coating 201 and the construction of interference effect in the optical system to increase the penetration or reflection characteristics. hard coating The properties of layer 201 depend on the number of layers, the thickness of each layer, and the refractive index difference at the interface of the layers. In order to control the maximum amount of light penetration and reduce unnecessary reflections, the reflectivity of the product is tested with a Hitachi U4100 reflectivity tester, and the reflectivity of this creation can reach below 6%. The reflectivity of the hard coating 201 can also be used to control the high reflectivity of the flexible cover, so that the reflectivity can be maximized in a single or across a range of spectral bands, so that it has a mirror reflection effect similar to glass. The refractive index n of the hard coat layer 201 can also be adjusted to have a spectroscopic or filter effect, so that the incident light can be divided into known transmitted light and reflected light outputs, or used for light penetration, light reflection, Light absorption or light attenuation, etc. When the wavelength of light and the angle of incidence are regulated, the optical flexible cover structure of the present invention can achieve the best performance by changing the refractive index and the thickness of the film layer. Any change in the parameter value will affect the path length of the light inside the optical flexible cover structure, and the phase value will also change as the light transmits. When light passes through the optically flexible cover structure, reflections occur in the two refractive index changing interfaces on either side of the first hard coat layer 2011 and the second hard coat layer 2012 . To minimize reflections, ideally when the two reflective moieties recombine at the first interface, there will be a 180° phase shift between them. The refractive index affects not only the optical path length, but also the reflectivity characteristics at each hard coat 201 interface. The reflectivity is defined by the Fresnel equation, which provides how the amount of reflectivity occurs from the change in refractive index at the interface when light is normally incident.

In order for the reviewers to have a better understanding of the structure and application scenarios covered by this creation, Figure 2 shows another optical flexible cover structure diagram of this creation, which is the same as the optical flexible cover structure in Figure 1, which includes: a The transparent plastic substrate layer 101 and at least two hard coating layers 201, wherein the thickness of the first hard coating layer 2011 is 3-8 μm, which is located on a surface of the transparent plastic substrate layer 101; wherein the thickness of the second hard coating layer 2012 is 1.5-8 μm 3 μm, which is located on the other surface of the first hard coating layer 2011; the thickness of the first hard coating layer 2011 is greater than that of the second hard coating layer 2012, and the transmittance of each single hard coating layer 201 is between 85~95% And the refractive index difference with the adjacent hard coating layer 201 is at least 0.5% or more; further, the thickness of the third hard coating layer 2013 is increased by coating to 1.5~3 μm, which is located on the other surface of the second hard coating layer 2012 ; The thickness of the fourth hard coating layer 2014 is 1.5~3 μm, which is located on the other surface of the third hard coating layer 2013; it can be increased according to optical requirements. Add the number of layers of its hard coat layer 201. The refractive index of the hard coating layer 201 is between 1.3 and 1.6; the optically flexible cover plate structure is characterized in that the transparent plastic substrate layer 101 and at least two hard coating layers 201 are stacked and combined, so that the optically flexible cover plate structure causes the light inside the Total reflection enables the optically flexible cover structure of the polymer to have an appearance close to that of glass, as well as anti-reflection properties, as well as anti-scratch and bending properties.

The present invention is an optically flexible cover structure, the structure is a transparent plastic substrate layer 101 and at least two hard coat layers 201, wherein the hard coat layer 201 is used with special thickness specifications and conventional coating materials to control the physical refractive index It can achieve the characteristics of bending rigidity, bending degree, scratch resistance and lowering manufacturing cost. Its structure is different from the conventional vacuum coating in the past in terms of thickness and refractive index characteristics, which is novel, advanced and practical. Correct. Therefore, it can effectively improve the lack of conventional knowledge, and has considerable practicality in use.

In view of the above, the specific structure disclosed in this creative embodiment can indeed provide optical flexible display applications, and solve the important problem of scratch resistance on the surface of the device. In terms of its overall structure, it has never been seen in similar products. Before the application It has not been published yet, and since it has met the statutory requirements of the Patent Law, it is possible to file an application for an invention patent in accordance with the law.

However, the above is only a preferred embodiment of this creation, and it should not limit the scope of the implementation of this creation, that is, any equivalent changes and modifications made according to the scope of the patent application for this creation and the contents of the description of the creation are all equivalents. shall remain within the scope of this creative patent.

101: Transparent plastic substrate layer

201: Hard Coating

2011: First hard coat

2012: Second hard coat

Claims (6)

An optically flexible cover plate structure, which comprises: a transparent plastic substrate layer, which is made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), cycloolefin polymer (Cyclo -olefin polymer), polyamide, polyimide or polyaramide (Polyaramide) material, the thickness of the transparent plastic substrate layer is between 15~100μm; at least two hard coatings, of which the first hard coating The thickness is 3-8 μm, which is located on one surface of the transparent plastic substrate layer; the thickness of the second hard coating layer is 1.5-3 μm, which is located on the other surface of the first hard coating layer; the first hard coating layer The thickness of each hard coating is greater than that of the second hard coating, the transmittance of each single hard coating is between 85% and 95%, and the refractive index difference with the adjacent hard coating is at least 0.5% or more; wherein, the hard coating is composed of at least one silicon oxide. Alkane resin, polysilazane resin, epoxy resin, acrylic resin, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), cycloolefin polymer (Cyclo- olefin polymer), polyamide, polyimide or polyaramide (Polyaramide) polymer material, which is mixed with 1~10% by weight of aluminum, tin, magnesium, phosphorus relative to the weight of the polymer material , cerium, zirconium, titanium, cesium, barium, strontium, niobium, zinc and boron at least one oxide and/or silicon oxide mixed with magnesium fluoride, the refractive index of the hard coating is between 1.3~1.6 The optically flexible cover structure is characterized in that the transparent plastic substrate layer and at least two hard coatings are stacked and combined to cause the optically flexible cover structure to cause total internal reflection of light, so that the polymer optically flexible cover structure has close to Appearance of glass, its total light transmittance (wavelength range 380-780nm) ≧90%, haze <1%, and has scratch resistance and bending resistance Characteristics, its hardness is ≧5H, its bending resistance times In-folding: Bending radius R=1.5mm, up to 200,000 times, Out-folding: Bending radius R=3mm, up to 200,000 times. The optically flexible cover plate structure according to claim 1, wherein the refractive index of the transparent plastic substrate layer is between 1.6 and 1.7. The optically flexible cover plate structure according to claim 1, wherein the refractive index of the first hard coating layer in the at least two hard coating layers is between 1.3 and 1.4. The optically flexible cover plate structure according to claim 1, wherein the refractive index of the second hard coating layer in the at least two hard coating layers is between 1.5 and 1.6. The optically flexible cover plate structure according to claim 1, wherein the at least two hard coating layers are stacked on each other, with a total thickness of 6.5-12 μm, and are superimposed on a surface of the transparent plastic substrate layer. According to the optically flexible cover plate structure according to claim 1, the curvature is less than or equal to 5mm.

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