阅读说明：本技术 一种柔性全息基元膜及其制备方法和应用 (Flexible holographic base element film and preparation method and application thereof ) 是由 王广军 余为伟 于 2019-11-29 设计创作，主要内容包括：本发明涉及3D显示领域,公开了一种柔性全息基元膜及其制备方法和应用,基元膜整体为柔性可弯曲薄膜结构,由若干相间平行排列的反射层和透明层组成,反射层为具有反射光线功能的反射膜,用于反射光线,透明层用于透射光线,柔性全息基元膜的水平夹持下垂长度为L(cm),可对折次数为n,满足：L≥5或者n*L>9,与现有高精度光学玻璃加工工艺极其高昂的加工成本相比,本发明所述制备方法的材料成本以及加工工艺成本都较低,适合大范围推广,同时基于本发明所述的柔性全息基元膜制备的3D显示全息膜,可以做成卷轴式屏幕、曲面屏幕等,灵活度较高,不使用时方便收纳,占用空间较小。(The invention relates to the field of 3D display, and discloses a flexible holographic base film and a preparation method and application thereof, wherein the whole base film is of a flexible bendable film structure and consists of a plurality of reflecting layers and transparent layers which are arranged in parallel at intervals, the reflecting layers are reflecting films with the function of reflecting light rays and are used for reflecting light rays, the transparent layers are used for transmitting light rays, the horizontal clamping sag length of the flexible holographic base film is L (cm), the folding times are n, and the requirements are met: l is more than or equal to 5 or n L is more than 9, compared with the extremely high processing cost of the existing high-precision optical glass processing technology, the material cost and the processing technology cost of the preparation method are low, the preparation method is suitable for large-scale popularization, and meanwhile, the 3D display holographic film prepared based on the flexible holographic element film can be made into a scroll screen, a curved screen and the like, has high flexibility, is convenient to store when not used, and occupies a small space.)

1. A flexible holographic base film, comprising: the whole element film (1) is of a flexible bendable film structure and consists of a plurality of reflecting layers (2) and transparent layers (3) which are arranged in parallel at intervals, wherein the reflecting layers (2) are reflecting films with light reflecting functions and used for reflecting light, and the transparent layers (3) are used for transmitting light;

the horizontal clamping sagging length of the flexible holographic base element film is L (cm), the folding times are n, and the requirements are met: l is more than or equal to 5 or n L is more than 9.

2. A flexible holographic element film according to claim 1, wherein: the thickness of the reflecting layer (2) is 0.1-25 mu m, the thickness of the transparent layer (3) is 2-1 mm, and the thickness of the transparent layer (3) is larger than that of the reflecting layer (2).

3. A flexible holographic element film according to claim 1, wherein: the reflecting film is any one of aluminum foil, iron foil, tin foil, zinc foil, copper foil, chromium foil, nickel foil and titanium foil.

4. A flexible holographic element film according to claim 1, wherein: the transparent layer (3) is a glue layer which is in a transparent state after being cured and/or a transmission film layer which is bonded through transparent glue.

5. A flexible holographic base film according to claim 4, wherein: the transparent glue is any one of epoxy resin AB glue, UV glue, shadowless glue, transparent glass glue, transparent wood glue and transparent all-purpose glue.

6. A flexible holographic base film according to claim 4, wherein: the transmission film is any one of a plastic film, a PMMA film, an lPMMA film, a PS film, a PC film, a styrene acrylonitrile film, an MS film, a PET film, a PETG film, an ABS film, a PP film, a PA film, an SAN film, an MS film, an MBS film, a PES film, a CR-39 film, a TPX film, a HEMA film, an F4 film, an F3 film, an EFP film, a PVF film, a PVDF film, an EP film, a PF film, an UP film, a cellulose acetate film, a cellulose nitrate film, an EVA film, a PE film, a PVC film, an amorphous cycloolefin film and a modified bisphenol A epoxy resin film which are made of transparent materials.

7. The method of claim 1, comprising the steps of:

1) preparing a cured pile:

a) stacking a plurality of pre-cut reflecting films layer by layer to form a reflecting film stack;

b) soaking the whole reflecting film stack in transparent glue water until the transparent glue water completely permeates into gaps among the reflecting films, and taking out the reflecting film stack;

c) standing and curing, wherein in the curing process, a certain pressure is applied to extrude out redundant glue in gaps between the reflecting films to control the thickness of a glue layer, and a curing stack arranged between the glue layer and the reflecting films is formed after curing, wherein the reflecting films are reflecting layers (2), and the glue layer is a transparent layer (3);

2) preparing a basic element film: grinding a smooth surface in the direction vertical to the plane of the reflecting layer (2) to be recorded as a cutting reference surface, cutting a sheet from the solidified pile along the direction parallel to the cutting reference surface to be recorded as a substrate film (1), wherein the newly cut surface on the solidified pile is the cutting reference surface of the next cutting, repeating the cutting step, and cutting the solidified pile of the step 1) into a plurality of substrate films (1).

8. The method of claim 7, wherein the method comprises: the cured mass described in step 1) can also be prepared by:

the reflecting film is placed on a plane, transparent glue is uniformly coated on the reflecting film, then another layer of reflecting film is stacked on the transparent glue layer, the stacking process is repeated to form a structure in which the reflecting film and the transparent glue are stacked alternately, and a cured pile is formed after standing and curing.

9. The method of producing a flexible holographic base film according to claim 7 or 8, wherein: adding at least one transmissive film according to claim 6 between two adjacent reflective films in a stacked manner.

10. The method of producing a flexible holographic base film according to claim 7 or 8, wherein: before the cutting in the step 2), a transparent protective film is bonded on the cutting reference surface by using transparent glue, and the cutting is performed to obtain a basic element film (1) with the transparent protective film, or one surface or two surfaces of the basic element film (1) after the cutting is completed are bonded with a transparent protective film, wherein the transparent protective film is any one of transparent glass, acrylic, plastic film, PMMA film, lPMMA film, PS film, PC film, styrene acrylonitrile film, MS film, PET film, PETG film, ABS film, PP film, PA film, SAN film, MS film, MBS film, PES film, CR-39 film, TPX film, HEMA film, F4 film, F3 film, EFP film, PVF film, PVDF film, EP film, PF film, UP film, cellulose acetate film, cellulose nitrate film, EVA film, PE film, PVC film, amorphous cycloolefin film and modified bisphenol A epoxy film.

11. Use of a flexible holographic substrate film prepared by a method of preparation of a flexible holographic substrate film according to claim 7 or 8, wherein: the flexible holographic base film (1) is applied to preparing a flexible 3D display holographic film, and specifically comprises the following steps:

two flexible substrate films (1) are bonded together up and down by using transparent glue, a flexible 3D display holographic film is formed after curing, the reflecting layer (2) and the transparent layer (3) on the two substrate films (1) are staggered by an included angle theta to form a grid (4) during bonding, the theta is more than or equal to 87 degrees and less than or equal to 93 degrees, and the horizontal clamping sagging length L (cm) of the flexible 3D display holographic film and the folding times n meet the following requirements: n L >9 or L is more than or equal to 5, and the element film (1) is provided with a flexible transparent protective film or is not provided with the transparent protective film.

12. Use of a base film with a transparent protective film according to claim 10, wherein: the application of the base element film (1) with the transparent protective film in the preparation of the hard 3D display holographic projection screen specifically comprises the following steps:

one element film (1) with a hard transparent protective film is adhered to the other element film (1) or the element film (1) with the transparent protective film up and down by using transparent glue, and the reflecting layer (2) and the transparent layer (3) on the two element films (1) are staggered at an included angle theta to form a grid (4), wherein the theta is more than or equal to 87 degrees and less than or equal to 93 degrees.

Technical Field

The invention relates to the field of 3D display, in particular to a flexible holographic base film and a preparation method and application thereof.

Background

The 3D display technology is capable of displaying stereoscopic pictures in space, and is the mainstream direction of the next generation display technology. Although there are many solutions for realizing 3D display, such as volume display technology, stereo image pair technology, pepper's ear illusion, etc., there is no perfect 3D solution at present, and the main reason is the lack of optical glass element for large area light source manipulation.

The traditional optical glass processing technology can only process microstructures on a hundred-micron scale, the processing requirement of high-precision large-area optical glass and high processing cost are met, the optical glass is made of hard materials, and the problems of breakage, residual stress and the like are easily caused in the processing process.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at the problems that the processing cost of the traditional high-precision large-area optical glass is high in the prior art, and the yield is affected by the easy breakage of the glass, the residual stress and the like in the processing process, the flexible holographic base film and the preparation method and application thereof are provided.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a flexible holographic element film is of a flexible bendable film structure and consists of a plurality of reflecting layers and transparent layers which are arranged in parallel at intervals, wherein the reflecting layers are reflecting films with the function of reflecting light rays and used for reflecting light rays, and the transparent layers are used for transmitting light rays;

the horizontal clamping sagging length of the flexible holographic base element film is L (cm), the folding times are n, and the requirements are met: l is more than or equal to 5 or n L is more than 9.

Furthermore, the thickness of the reflecting layer is 0.1-25 μm, the thickness of the transparent layer is 2-1 mm, and the thickness of the transparent layer is greater than that of the reflecting layer.

Further, the reflective film is any one of aluminum foil, iron foil, tin foil, zinc foil, copper foil, chromium foil, nickel foil and titanium foil.

Further, the transparent layer is a glue layer in a transparent state after being cured and/or a transmission film layer bonded by transparent glue.

Further, the transparent glue is any one of epoxy resin AB glue, UV glue, shadowless glue, transparent glass glue, transparent wood glue and transparent all-purpose glue.

Further, the transmission film is any one of a plastic film, a PMMA film, an lPMMA film, a PS film, a PC film, a styrene acrylonitrile film, an MS film, a PET film, a PETG film, an ABS film, a PP film, a PA film, an SAN film, an MS film, an MBS film, a PES film, a CR-39 film, a TPX film, a HEMA film, an F4 film, an F3 film, an EFP film, a PVF film, a PVDF film, an EP film, a PF film, an UP film, a cellulose acetate film, a cellulose nitrate film, an EVA film, a PE film, a PVC film, a novel amorphous thermoplastic polyester film, an amorphous cycloolefin film, and a modified bisphenol a epoxy resin film.

The invention also provides a preparation method of the flexible holographic base element film, which comprises the following steps:

1) preparing a cured pile:

a) stacking a plurality of pre-cut reflecting films layer by layer to form a reflecting film stack;

b) soaking the whole reflecting film stack in transparent glue water until the transparent glue water completely permeates into gaps among the reflecting films, and taking out the reflecting film stack;

c) standing and curing, wherein in the curing process, a certain pressure is applied to extrude out redundant glue in gaps between the reflecting films to control the thickness of a glue layer, and a curing stack arranged between the glue layer and the reflecting films is formed after curing, wherein the reflecting films are reflecting layers, and the glue layer is a transparent layer;

2) preparing a basic element film: grinding a smooth surface in the direction vertical to the plane of the reflecting layer, recording the smooth surface as a cutting reference surface, cutting a sheet from the solidified pile along the direction parallel to the cutting reference surface, recording the sheet as a base element film, wherein the newly cut surface on the solidified pile is the cutting reference surface for the next cutting, and repeating the cutting step to cut the solidified pile in the step 1) into a plurality of base element films.

Further, the cured pile described in step 1) may also be prepared by:

the reflecting film is placed on a plane, transparent glue is uniformly coated on the reflecting film, then another layer of reflecting film is stacked on the transparent glue layer, the stacking process is repeated to form a structure in which the reflecting film and the transparent glue are stacked alternately, and a cured pile is formed after standing and curing.

Further, at least one layer of the transmission film is added between adjacent reflection films in a stacking mode.

Further, before the cutting in the step 2), a transparent protective film is bonded on the cutting reference surface by using transparent glue, and the element film with the transparent protective film is obtained after the cutting, or one or two surfaces of the element film after cutting is bonded with a transparent protective film, wherein the transparent protective film is any one of glass, acrylic, plastic film, PMMA film, LPMMA film, PS film, PC film, styrene acrylonitrile film, MS film, PET film, PETG film, ABS film, PP film, PA film, SAN film, MS film, MBS film, PES film, CR-39 film, TPX film, HEMA film, F4 film, F3 film, EFP film, PVF film, PVDF film, EP film, PF film, UP film, cellulose acetate film, nitric acid film, EVA film, PE film, PVC film, novel amorphous thermoplastic polyester film, amorphous cycloolefin film and modified bisphenol A epoxy film.

Further, the flexible holographic element film is applied to the preparation of a flexible 3D display holographic film, and specifically comprises the following steps: the two flexible element films are bonded together up and down by using transparent glue, a flexible 3D display holographic film is formed after curing, the reflecting layers and the transparent layers on the two element films are staggered at an included angle theta to form a grid when bonding, the theta is more than or equal to 87 degrees and less than or equal to 93 degrees, and the horizontal clamping sagging length L (cm) of the flexible 3D display holographic film and the number n of folding times meet the following requirements: n L >9 or L is more than or equal to 5, and the element film is provided with a flexible transparent protective film or is not provided with the transparent protective film.

Further, the element film with the transparent protective film is applied to the preparation of a hard 3D display holographic projection screen, and specifically comprises the following steps:

one element film with a hard transparent protective film (such as glass or acrylic) is bonded with the other element film or the element film with the transparent protective film up and down by using transparent glue, and the reflecting layers and the transparent layers on the two element films are staggered at an included angle theta to form a grid, wherein the theta is more than or equal to 87 degrees and less than or equal to 93 degrees.

Compared with the prior art, the invention has the advantages that:

the flexible holographic base film with the micron-sized ultra-fine structure can be prepared without a complex film coating process, and compared with the extremely high processing cost of the existing high-precision optical glass processing process, the preparation method has the advantages that the material cost and the processing process cost are low, and the preparation method is suitable for large-scale popularization; meanwhile, the holographic element film with the grids is flexible, so that the holographic element film is not easy to break when being processed, the problems of residual stress generated in the glass processing process and the like are avoided, the yield is greatly improved, the holographic element film can be made into a scroll screen, a curved screen and the like when being specifically applied, the flexibility is higher, the holographic element film is convenient to store when not being used, and the occupied space is smaller.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Figure 1 is a front view of a structure of a elementary film 1 in which the transparent layer 3 is a cured layer of transparent glue,

figure 2 is a front view of a structure in which a transparent layer 3 is a elementary film 1 to which a transmission film is bonded by transparent glue,

figure 3 is an enlarged view of a portion of i in figure 2,

FIG. 4 is a structural view of a cell film 1 with a transparent protective film,

figure 5 is a perspective view of a 3D display holographic film structure,

figure 6 is a front view and a top view of figure 5,

figure 7 is a diagram of an aero-levitation display system,

figure 8 is a schematic diagram of the imaging optical path of a 3D display holographic film,

figure 9 is a side view of figure 8,

figure 10 is a schematic diagram of the partial internal ray reflection at ii in figure 9,

figure 11 is a diagram of the effect of a flexible holographic screen for an air suspension display system application,

FIG. 12 is a graph showing the simulation effect of the imaging light path of the holographic film in 3D,

the reference numbers are as follows:

a base film 1, a reflective layer 2, a transparent layer 3, a grid 4, a holographic projector 10, a projection screen 20, an interactive response unit 30, a processor 40, and a motion actuator 50.

Detailed Description

The following detailed description of the present invention is given for the purpose of better understanding technical solutions of the present invention by those skilled in the art, and the present description is only exemplary and explanatory and should not be construed as limiting the scope of the present invention in any way.

Referring to fig. 1 to 12, the present invention provides a flexible holographic element film, wherein the whole element film 1 is a flexible bendable film structure, the horizontal clamping sagging length is l (cm), the number of folding times is n, and the following requirements are satisfied: l is more than or equal to 5 or n L is more than 9;

in practical application, in order to ensure the reliability as much as possible, n is preferably more than or equal to 2 and L is more than 9;

it should be noted that, where n is the number of times of folding, the area taken during the test is 100cm²The square flexible holographic base film 1 is characterized in that the base film 1 is folded into a rectangle along the middle line position of the square (or within 1cm near the middle line position), then the folded base film 1 is clamped between two flat plates, 10-20N of force is applied to pressurize for 3-5 s, then the base film 1 is opened (at the moment, a folding test is completed once), whether the base film 1 generates local micro-cracks or is broken into two parts along creases is checked, if not, the test is repeated until the base film 1 generates local micro-cracks or is broken into two parts, the test is stopped, and the total folding times in the test process are recorded as N;

wherein L is the horizontal clamping sagging length, the test method comprises the following steps: taking a narrow strip element film 1 with the width of 5cm +/-0.5 cm and the length of about 25cm, enabling one end of the narrow strip element film to be tightly attached to a horizontal reference table top, ensuring that the length of the narrow strip extending out of the table top is 20cm +/-1 cm, standing, and measuring the vertical height difference between the end point of the narrow strip extending out of the table top and the horizontal reference table top after the narrow strip is stabilized to be recorded as a horizontal droop length L;

the test is an accelerated test means, the reliability of a sample in a long-term use process can be rapidly judged, the flexible 3D display base element film 1 needs to bear operations such as winding, storage, opening and the like for many times when being applied, the operation is calculated according to the designed 5-year service life, the whole life cycle needs to be stored and unfolded for about 10000 times, and in order to accelerate the evaluation of the service life of the base element film 1, the folding test and the horizontal clamping droop length test are adopted in the invention;

when n is greater than L9, the larger n is, the smaller the ultimate bending curvature radius of the base element film 1 is, the stronger the breaking resistance is, and meanwhile, the larger L is, the better the flexibility of the base element film 1 is, the more difficult the base element film 1 structure is to be damaged due to winding, experiments show that the base element film 1 structure is basically equivalent to 10000 times of opening and closing tests when n is greater than L9, the requirement on the minimum design life is met, and if the n is smaller, the quality problem is easy to occur in the service cycle of a product, and the customer experience is reduced;

in practical application, some transparent adhesive tapes and transparent films which are relatively hard after being cured can be used, so that the prepared flexible holographic base film 1 can be broken when being folded in half, but the structure can not be damaged when being wound, and the flexible holographic base film is also suitable for winding screens. For such materials, as long as the prepared base membrane 1 can be wound into a cylinder with the diameter less than 5cm, the whole base membrane 1 is relatively flexible, and the fracture loss in the processing process is small. Generally, when L.gtoreq.5 cm, the elementary film can be wound into a cylindrical shape having a diameter of less than 5cm without breaking.

As shown in fig. 1 to 3, the substrate film 1 is composed of a plurality of reflective layers 2 and transparent layers 3 arranged alternately, the reflective layers 2 are metal foils capable of reflecting light or other reflective films with reflective function, the reflective layers 2 are used for reflecting light, it should be noted that if the reflective layers are too thick, too much light is shielded, the thinner the reflective layers are, but in consideration of the difficulty and cost of the process preparation, the reflective films are aluminum foils, iron foils, tin foils, zinc foils, copper foils, chromium foils, nickel foils, titanium foils or other reflective films capable of reflecting light, and the thickness of the reflective films is 0.1 μm to 25 μm;

the transparent layer 3 is a transparent glue layer or a transmission film adhered between adjacent reflecting layers and used for transmitting light, and the thickness of the transparent layer 3 is always larger than that of the reflecting layer 2;

wherein the transparent glue can be any one of UV glue, shadowless glue, transparent glass glue, transparent wood glue and transparent all-purpose glue, and the thickness of the transparent layer can be controlled to be 2 mu m-1 mm;

the transmission film may be any one of a transparent plastic film, a PMMA film, an lPMMA film, a PS film, a PC film, a PE film, a styrene acrylonitrile film, an MS film, a PET film, a PETG film, an ABS film, a PP film, a PA film, a SAN film, an MS film, an MBS film, a PEs film, a CR-39 film, a TPX film, a HEMA film, an F4 film, an F3 film, an EFP film, a PVF film, a PVDF film, an EP film, a PF film, an UP film, a cellulose acetate film, a cellulose nitrate film, an EVA film, a PE film, a PVC film, a novel amorphous thermoplastic polyester film, an amorphous cycloolefin film, and a modified bisphenol a epoxy resin film.

The invention also provides a preparation method of the flexible holographic base element film, which comprises the following specific steps:

1) preparing a cured pile:

a) stacking a plurality of pre-cut reflecting films layer by layer to form a reflecting film stack;

b) the whole reflecting film stack is soaked in transparent glue water until the transparent glue water completely permeates into gaps among the reflecting films and then is taken out, and it is required to be explained that the reflecting films are stacked and then are fluffy, gaps exist among the layers, so that when the reflecting films are contacted with the transparent glue water, the transparent glue water can go deep into the layers under the action of surface tension and is completely filled, bubbles are not easy to appear, and the glue water has a bonding effect on various materials, so that the reflecting films are very easy to infiltrate the surfaces of the reflecting films, and the transparent glue water can be filled among the reflecting films under the action of the surface tension and is similar to a capillary phenomenon;

c) standing and curing, wherein in the curing process, a certain pressure is applied to extrude out redundant glue in gaps between the reflecting films so as to control the thickness of a glue layer, and a curing stack arranged between the glue layer and the reflecting films is formed after curing, wherein the reflecting films are reflecting layers 2, and the glue layer is a transparent layer 3;

2) preparing a basic element film: grinding a smooth surface in the direction vertical to the plane of the reflecting layer, marking the smooth surface as a cutting reference surface, cutting a sheet from the solidified pile along the direction parallel to the cutting reference surface, marking the sheet as a base element film 1, wherein the newly cut surface on the solidified pile is the cutting reference surface of the next cutting, and repeating the cutting step to cut the solidified pile in the step 1) into a plurality of base element films 1.

Wherein, the preparation of the curing stack in the step 1) can also adopt the following mode:

the reflecting film is placed on a plane, transparent glue is uniformly coated on the reflecting film, then another layer of reflecting film is stacked on the transparent glue layer, the stacking process is repeated to form a structure in which the reflecting film and the transparent glue are stacked alternately, and a cured pile is formed after standing and curing.

In order to reduce the amount of transparent glue and further increase the thickness of the transparent layer 3, at least one transparent transmission film as described above may also be adhered between the two reflective layers 2 by transparent glue.

It should be noted that the transparent layer 3 is formed by curing transparent glue or by bonding one or more layers of transparent transmission films as described above with transparent glue, and based on the materials of the transparent glue and the transmission films selected above, the cured transparent layer 3 has better flexibility, and the substrate film 1 has better flexibility after being cut into the substrate film 1.

Reference may be made in particular to the thicknesses of the reflective layer 2, the transparent layer 3 and the elementary film 1 in the following table:

thickness of reflecting layer (mum)	Thickness of transparent layer (μm)	Elementary film thickness (. mu.)m)
			0.1	1	1
1	2	2
			5	10	10
10	20	20
			15	30	30
20	50	50
			25	100	100
25	300	300
			25	1000	1000

The following examples are further illustrative of the method for manufacturing a flexible holographic element film according to the present invention, wherein the flexible holographic element film is made of transparent epoxy resin AB glue with a thickness of 20 μm and a reflective layer 2 of 10 μm aluminum foil and a transparent layer 3 of 20 μm, and the method comprises the following steps: