CN117102702B

CN117102702B - Visual line diameter invisible partitioned PDLC film and preparation method thereof

Info

Publication number: CN117102702B
Application number: CN202311385790.5A
Authority: CN
Inventors: 吴永隆; 孙瑞
Original assignee: Shanghai Longsheng Photoelectric New Material Co ltd
Current assignee: Shanghai Longsheng Photoelectric New Material Co ltd
Priority date: 2023-10-25
Filing date: 2023-10-25
Publication date: 2024-02-20
Anticipated expiration: 2043-10-25
Also published as: CN117102702A

Abstract

The invention belongs to the technical field of PDLC films, and particularly relates to a partitioned PDLC film with invisible visual line diameter and a preparation method thereof, wherein the partitioned PDLC film comprises the steps of firstly preparing the PDLC film and then performing laser partitioning on the PDLC film; the laser partitioning process comprises the following steps: s1, placing a PDLC film on a negative pressure platform; s2, laser is emitted by an ultraviolet laser to penetrate through the first substrate layer, and laser cutting is conducted on the first conductive layer, wherein a light spot of the laser is controlled to deviate from the first conductive layer and is focused on a part of the first substrate layer close to the first conductive layer; the power is controlled to be 0.2-0.8W, the cutting speed is 50-120mm/s, and the light spot is 15-25 mu m; s3, baking and cooling. The laser etching partition line of the partitioned PDLC film is invisible visually, is easy to cut by laser, has no surface pollution, can realize the dimming function, has minimum damage to a PDLC layer by laser cutting, and improves the partition yield.

Description

Visual line diameter invisible partitioned PDLC film and preparation method thereof

Technical Field

The invention belongs to the technical field of PDLC films, and particularly relates to a zoned PDLC film with invisible visual line diameter and a preparation method thereof.

Background

With the expansion of the application field of PDLC dimming films and the improvement of the general familiarity, customers put higher demands on pattern display and customized pattern display of PDLC dimming films. After the PDLC dimming film is partitioned according to the pattern, each area is used as an electrode, and different areas are electrified respectively, so that various conversion combinations such as transparent pattern areas, vaporific non-pattern areas, vaporific pattern areas, transparent non-pattern areas and the like can be realized, the whole film is completely transparent or completely vaporific, and the jumping and conversion among different modes can be realized through setting an electrified electric control program.

The PDLC film is subjected to regional dimming, the conducting layer is subjected to laser cutting according to a regional pattern, the conducting layer on the whole surface is partitioned according to the pattern, and when a certain region is electrified, the certain region becomes transparent.

At present, laser cutting partition (obtaining finer wire diameter) is firstly carried out on an ITO film, and then PDLC film is manufactured by coating, which has the defects that: the ITO film is subjected to laser cutting processing, so that the surface of the ITO film is polluted, the appearance of the ITO film after being coated into a PDLC film is poor, a laser etching line is visible to naked eyes under conditions of strong light and the like, and the average yield is 20-30%, so that the cost is high.

It should be noted that this section of the disclosure only provides a background related to the present disclosure, and does not necessarily constitute prior art or known technology.

Disclosure of Invention

The invention aims to overcome the defects that a laser etching line generated by a laser cutting partitioning method of a PDLC film is visible and the production yield is low in the prior art, and provides a partitioned PDLC film with invisible visual line diameter and a preparation method thereof.

In order to achieve the above object, the present invention provides a method for preparing a segmented PDLC film with invisible line of sight, comprising preparing a PDLC film first, and then performing laser segmentation on the PDLC film; the PDLC film comprises a first protective film layer, a first substrate layer, a first conductive layer, a PDLC layer, a second conductive layer, a second substrate layer and a second protective film layer which are sequentially arranged.

The laser partitioning process comprises the following steps:

s1, placing a PDLC film on a negative pressure platform, and controlling the flatness of the negative pressure platform to be between-0.04 mm and +0.04mm;

s2, laser is emitted by an ultraviolet laser to penetrate the first substrate layer, and laser cutting is conducted on the first conductive layer along a preset cutting path, wherein a light spot of the laser is controlled to deviate from the first conductive layer and is focused on a part of the first substrate layer close to the first conductive layer, and only the first conductive layer located on one side of the PDLC layer is etched; and the conditions for the laser cutting include: the laser wavelength is 330-380nm, the power is 0.2-0.8W, the cutting speed is 50-120mm/s, and the light spot is 15-25 μm.

In some preferred embodiments of the present invention, the laser partitioning process further comprises: and S3, eliminating a heat affected zone at the etched line of the PDLC layer through baking and cooling.

Preferably, the baking conditions include: the temperature is 100-148 ℃, and the time is 10-30min.

In some preferred embodiments of the present invention, in S1, the flatness of the negative pressure controlling stage is between-0.02 mm and +0.02mm.

In some preferred embodiments of the present invention, in S2, the spot deviation distance of the laser is controlled such that the line width of the etched cutting line cut by the laser on the first conductive layer is less than or equal to 60 μm.

Further preferably, the spot deviation distance of the laser is controlled so that the line width of the etched cutting line cut by the laser on the first conductive layer is 35-60 μm.

In some preferred embodiments of the present invention, the laser partitioning process further comprises: after the laser cutting in the S2, pulse laser focusing treatment is further carried out on the inner part of the first substrate layer, so that a dodging area parallel to a preset cutting path is formed; the light homogenizing region is positioned on one side of the light spot focusing region of the laser cutting, which is far away from the first conductive layer, and the width of the light homogenizing region is not smaller than the line width of the etching cutting line on the first conductive layer.

Further preferably, the conditions of the pulsed laser focusing process include: the laser wavelength is 330-380nm, the power is 0.3-0.4W and is less than the power of laser cutting, the processing speed is 70-140mm/s and is greater than the cutting speed of laser cutting, the light spots after laser focusing are 5-10 mu m, and the interval between the light spots after focusing of adjacent lasers in pulse processing is more than 1.3 times, preferably 1.4-2.3 times of the light spots after laser focusing.

Further preferably, the thickness of the first substrate layer is 100-200 μm, and the distance d between the dodging region and the light spot focusing region is controlled to be 35-50 μm.

Further preferably, the width D of the dodging zone is 70-110 μm.

In some preferred embodiments of the present invention, the laser partitioning process further comprises: in S2, the distance between the ultraviolet laser and the PDLC film is measured through the altimeter, and the height of the ultraviolet laser is adjusted in real time according to the distance, so that the light spot deviation distance of laser is ensured.

In some preferred embodiments of the present invention, the conditions of the baking in S3 include: the low-temperature heating section is firstly carried out and the conditions include: the temperature is 100-135 ℃ and the time is 7-23min; the high temperature heating section is carried out again and the conditions include: the temperature is 136-145 ℃ and the time is 3-7min.

In some preferred embodiments of the present invention, the preparing a PDLC film further comprises: the high-refraction layer is arranged between the first substrate layer and the first conductive layer, the high-refraction layer is metal oxide or metal fluoride, the refractive index of the first substrate layer is 1.45-1.57, the refractive index of the first conductive layer is 1.9-2.1, and the refractive index of the high-refraction layer is 1.6-1.7.

Further preferably, the thickness of the high refractive layer is 2-8 μm, and the thickness of the first conductive layer is 20-50nm.

In some preferred embodiments of the present invention, the first conductive layer is a non-crystalline conductive material, and the UV transmittance of the non-crystalline conductive material is > 50%.

The invention also provides a zoned PDLC film with invisible line of sight produced by the aforementioned production method.

The beneficial effects are that:

the inventor of the present invention has found that, in order to reduce the visual visibility, only the single-sided conductive layer may be etched and cut, but since only the thinner micron-sized PDLC layer is spaced between the two conductive layers, it is very difficult for the laser to directly laser etch and cut the first conductive layer on the single side on the PDLC film without damaging the second conductive layer on the other side; and the laser etching can also generate traces on the first substrate layer and the PDLC layer, which affect the visual visibility. Based on this, the present invention has been further studied.

According to the technical scheme, the flatness of the negative pressure platform is controlled, laser cutting is performed under specific conditions, particularly, the focal spot of the laser is controlled to be placed on the upper side (upper focus) of the first conductive layer, as the energy of the focal spot is highest, the energy reaching the first conductive layer to be cut after the focal spot deviates is reduced, the energy and the cutting speed of the laser are controlled to be respectively in proper ranges, so that the laser can just cut off the first conductive layer, the etching cutting line consistent with the partition pattern is formed on the first conductive layer only, at the moment, the energy of the laser which passes through the PDLC layer is gradually reduced, the damage to the PDLC layer is smaller, the laser energy is effectively prevented from penetrating the PDLC layer to damage the second conductive layer, the partition yield is improved, and meanwhile, the trace caused by the cutting line diameter on the PDLC layer due to the fact that the laser focuses on the visibility of a cutting trace formed in the first substrate layer is reduced.

The laser cutting adopts an ultraviolet laser, the energy of the ultraviolet laser is low, the first conducting layer can be cut by penetrating through the first substrate layer, and the small power is matched with the rapid cutting speed by selecting the wavelength of the ultraviolet laser to be 330-380nm, so that the thermal influence on the film layer is reduced, and the smaller cutting line width is realized; meanwhile, the production efficiency is improved; and because the energy at the laser focus is highest, the focusing light spot with a proper size is controlled in a matched mode, the thermal influence of the laser in the first substrate layer is reduced, and the visibility of cutting traces formed in the first substrate layer due to the focusing of the laser is reduced.

In a word, the laser etching partition line (comprising the cutting line on the first conductive layer and the trace caused by the heat influence in the substrate layer (preferably including the trace caused in the PDLC layer)) of the partitioned PDLC film obtained by the preparation method is invisible visually, is easy to cut by laser, has no surface pollution, can realize the dimming function, has minimum damage to the PDLC layer by laser cutting, and improves the partition yield.

The inventors of the present invention have further studied and found that, since the first conductive layer is cut off by heat during laser cutting, the instantaneous heat causes alignment of liquid crystals in the PDLC layer, a heat affected zone is generated, refraction of light is affected, the line diameter of the subarea appears as a transparent line, and the influence of laser single-side etching on the PDLC layer is small. In the preferred scheme of the invention, the liquid crystal in the PDLC layer can be arranged isotropically and then cooled to restore the initial arrangement by matching with the baking under specific conditions, so that the orientation caused by laser is eliminated, the heat affected zone is eliminated, and the visual visibility of the trace in the PDLC layer is obviously weakened.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of one embodiment of the PDLC film of the present invention.

Fig. 2 is a schematic top view of a cross section of a micro heat dissipation interface in a light homogenizing zone according to the present invention.

Fig. 3 is a schematic structural diagram of a first conductive layer after laser cutting according to an embodiment of the present invention.

Description of the reference numerals

1. The light source comprises a first substrate layer, 2, a first conductive layer, 3, a PDLC layer, 4, a second conductive layer, 5, a second substrate layer, 6, a light homogenizing region, 7, a light spot focusing region, 8, etching cutting lines, 9 and an electrode.

Detailed Description

In the present invention, unless expressly stated or limited otherwise, a first feature being a second feature, "up", "down", or "in sequence" may be a direct contact between the first and second features, or an indirect contact between the first and second features via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein. Wherein the terms "optional" and "optionally" mean either comprising or not comprising (or may not be present).

In the present invention, the term "invisible line diameter" means that the line diameter of trace lines (abbreviated as "traces") caused in each layer after laser cutting for partitioning is invisible under a natural light under a visual overall PDLC film.

The invention provides a preparation method of a sectional PDLC film with invisible visual line diameter, which comprises the steps of firstly preparing the PDLC film, and then carrying out laser partition on the PDLC film; the PDLC film comprises a first protective film layer, a first substrate layer, a first conductive layer, a PDLC layer, a second conductive layer, a second substrate layer and a second protective film layer which are sequentially arranged. The first protective film layer and the second protective film layer are reserved for protecting the outer surfaces of the first substrate layer and the second substrate layer from being scratched, polluted and the like when laser partitioning and subsequent processing are carried out, and the first protective film layer and the second protective film layer are torn off when the PDLC film is actually used.

The method of producing a PDLC film according to the present invention may be performed according to the prior art, and the present invention is not limited thereto as long as the above-described laminate structure of the PDLC film can be obtained.

The laser partitioning process comprises the following steps: s1, placing the PDLC film on a negative pressure platform, and controlling the flatness of the negative pressure platform to be between-0.04 mm and +0.04mm. The PDLC film can be adsorbed by the negative pressure platform, so that the PDLC film is smooth and is not warped, and the accuracy of subsequent cutting is guaranteed.

It is understood that-0.04 mm refers to 0.04mm below the horizontal datum level of the negative pressure platform. +0.04mm refers to 0.04mm above the horizontal datum plane of the negative pressure platform.

The laser partitioning process further comprises the following steps: s2, laser is emitted through the ultraviolet laser to penetrate the first substrate layer, laser cutting is conducted on the first conductive layer along a preset cutting path, wherein a light spot of the laser is controlled to deviate from the first conductive layer and is focused on a part of the first substrate layer close to the first conductive layer, and only the first conductive layer located on one side of the PDLC layer is etched.

It is understood that the preset cutting path refers to the desired to-be-cut line partitioning the first conductive layer. Those skilled in the art can choose according to the actual needs.

In the present invention, preferably, the conditions for laser cutting include: the laser wavelength is 330-380nm, the power is 0.2-0.8W, the cutting speed is 50-120mm/s, and the light spot is 15-25 μm. The ultraviolet laser has low energy, and can penetrate through the substrate layer to cut the conductive layer. The thermal influence can be reduced by selecting the ultraviolet laser wavelength of 330-380nm and the low power, thereby being beneficial to realizing smaller cutting linewidth; the small power is matched with the rapid cutting speed, so that the thermal influence can be reduced, and the production efficiency is improved.

The power of laser cutting in the present invention refers to the power actually applied to the corresponding film layer, which is slightly lower than the power of the laser cutting device.

The invention cuts only the first conductive layer, and the second conductive layer on the other side is not damaged.

It will be appreciated that after the first conductive layer is cut, a plurality of partitions are formed, each partition is provided with an electrode correspondingly to realize power-on (in a specific embodiment, as shown in fig. 3, a plurality of etching cutting lines 8 are etched on the first conductive layer 2 by laser, the first conductive layer 2 is divided into 6 partitions, and each partition is respectively provided with an electrode 9), the second conductive layer is also provided with an electrode correspondingly and the electrodes are collinear, and can be respectively powered on with the electrodes on the first conductive layer, and different patterns are arranged on different partitions in a matching manner to realize dimming of different partition areas. For example, when the first conductive layer as a whole and the second conductive layer are simultaneously charged when the respective partitions are simultaneously energized, the PDLC film assumes a transparent state; when a certain partition is electrified, the partition presents a transparent state, and the partition which is not electrified presents mist. The cutting mode is simple, and dimming of a closed-loop partition area can be realized.

In some preferred embodiments of the present invention, in S2, the spot deviation distance of the laser is controlled such that the line width of the etched cutting line cut by the laser on the first conductive layer is less than or equal to 60 μm. Under the preferred scheme, enough cutting energy can be ensured to completely cut the first conductive layer in the thickness direction, and meanwhile, the damage to the second conductive layer is reduced.

More preferably, the spot deviation distance of the laser is controlled so that the line width of the etched cutting line cut by the laser on the first conductive layer is 35-60 μm. The preferred line width of the invention is adopted, and the focus bias of the laser light spot is suitable, so that the line width of the etching cutting line is suitable, the partition line trace (or called trace) caused by laser cutting on the PDLC film is obviously reduced under the condition of not damaging the second conductive layer, the trace caused on the PDLC film is further invisible under the visual sense, and the partition yield is improved.

In the invention, the laser cutting is performed by the heat of the laser light spot, and the heat radiation has a certain angle, so that the upper and lower sizes of the etching cutting lines on the first conductive layer are different, and the line width of the etching cutting lines is only 35-60 mu m.

The inventors of the present invention have further studied and found that laser penetrates through the first substrate layer, and the laser spot is focused only on the upper side of the first conductive layer to achieve only laser etching of the first conductive layer, but since the energy of the focused spot of the laser is highest, even under small laser energy, traces (about 15-45 μm, similar to the laser spot) are formed at the focusing area of the cutting laser in the first substrate layer, and under strong light and other conditions, visible traces are very easy to appear. In some preferred embodiments of the present invention, the laser partitioning further comprises: after the laser cutting in the S2, pulse laser focusing treatment is further carried out on the inner part of the first substrate layer, so that a dodging area parallel to a preset cutting path is formed; the light homogenizing region is positioned on one side of the light spot focusing region of the laser cutting, which is far away from the first conductive layer, and the width of the light homogenizing region is not smaller than the line width of the etching cutting line on the first conductive layer. In the preferred scheme, pulse laser focusing is performed at the outer side of the light spot focusing area, the laser generates pulses in a very short time, and the energy enables the focusing part inside the first substrate layer to be heated and broken, so that a very small micro scattering interface is generated (a plurality of micro scattering points exist in the micro scattering interface as shown in fig. 2), a light homogenizing area is formed, light is refracted and reflected and scattered in the light homogenizing area, effective light diffusion and uniform light are formed, and accordingly the visible conditions of cutting the laser focusing area and the cutting line of the first conductive layer in the lower first substrate layer are greatly reduced and eliminated.

Further preferably, the conditions of the pulsed laser focusing process include: the laser wavelength is 330-380nm, the power is 0.3-0.4W and is smaller than the power of laser cutting, and the processing speed is 70-140mm/s and is larger than the cutting speed of laser cutting. In the preferred scheme, the processing speed is improved by reducing the power, and the damage to other areas in the first substrate layer is minimized while the uniform light region of the tiny micro-scattering interface is facilitated to be generated.

Further preferably, the conditions of the pulsed laser focusing process include: the laser focused light spots are 5-10 mu m, and the interval between the adjacent laser focused light spots in pulse treatment is more than 1.3 times, preferably 1.4-2.3 times of the laser focused light spots. According to the preferable scheme, due to the adoption of the appropriate laser focusing rear light spots and the interval thereof, under the condition of reducing equipment requirements, the mutual overlapping and mutual influence of different laser focusing are avoided, the formation of a light homogenizing region with better scattered micro-scattering interfaces in the first substrate layer is facilitated, the light diffusion effect is further improved, and the visible conditions of cutting the laser focusing region and the first conductive layer cutting line in the lower first substrate layer are further eliminated.

The pulsed laser focusing treatment of the invention adopts an ultraviolet laser.

Further preferably, the thickness of the first substrate layer is 100-200 μm, and the distance d between the dodging region and the light spot focusing region is controlled to be 35-50 μm. According to the preferred scheme, the distance d between the dodging area and the outer side of the facula focusing area is proper, so that the overlapping of the laser cutting and the heat influence of the laser focusing used by the dodging area is avoided, the visible trace formed by the laser in the first substrate layer is further effectively eliminated, and meanwhile, the phenomenon that the surface quality of the first substrate layer is influenced by the heat influence of the laser generated by the laser which is too close to the surface of the first substrate layer is avoided.

Further preferably, the width D of the dodging zone is 70-110 μm. According to the preferable scheme, the width of the light homogenizing region exceeds the width of the cutting trace formed at the lower part, so that when incident light is incident from different angles, the invisible effect of the cutting laser focusing region and the cutting line of the first conductive layer in the first substrate layer at the lower part can be ensured even under the action of considering different refractive indexes of the first substrate layer, the first conductive layer, the PDLC layer and the like.

The inventors of the present invention have further studied and found that the change in the laser focus with respect to the first conductive layer due to the change in the height of the negative pressure stage and the change in the height of the PDLC film affects the cutting or the damage to the second conductive layer. In some preferred embodiments of the present invention, the laser partitioning further comprises: in S2, the distance between the ultraviolet laser and the PDLC film is measured through the altimeter, and the height of the ultraviolet laser is adjusted in real time according to the distance, so that the light spot deviation distance of laser is ensured. In this preferred scheme, the control of ultraviolet laser's height, the control of cooperation negative pressure platform roughness can more accurate control laser's facula offset distance to more do benefit to accurate cutting, and do benefit to the stability of cutting process, effectively avoid because the altitude variation is too high and lead to ultraviolet laser's height to come not to adjust and influence the probably emergence of cutting. In addition, the specific partial-focus cutting mode and the flatness control of the negative pressure platform are matched with the setting of the height indicator, so that the method has the advantage of increasing the fault-tolerant space of the actual cutting process, and is more beneficial to improving the production yield.

The inventors have also studied and found that, during laser cutting, the conductive layer is cut off by heat, and the instantaneous heat orients the liquid crystal, thereby generating a heat affected zone, affecting the refraction of light, and making the line diameter of the division look transparent. In this regard, in the present invention, preferably, the laser partitioning process further includes the steps of: and S3, eliminating a heat affected zone at the etched line of the PDLC layer through baking and cooling.

Preferably, the baking conditions include: the temperature is 100-148 ℃, and the time is 10-30min. The baking temperature is lower than the crystallization temperature of the first conductive layer, so that the heat affected zone in the PDLC layer can be eliminated by baking under the condition that the first conductive layer is not affected.

In the scheme of the preferable two-stage baking condition, the uniform heat affected zone is baked for a long time at a lower temperature, and the short-time baking at a high temperature is quickly diffused, so that the heat affected zone in the PDLC layer is eliminated, and meanwhile, the heat damage of the PDLC layer is further reduced.

In some preferred embodiments of the present invention, the preparing a PDLC film further comprises: the high-refraction layer is arranged between the first substrate layer and the first conductive layer, the high-refraction layer is metal oxide or metal fluoride, the refractive index of the first substrate layer is 1.45-1.57, the refractive index of the first conductive layer is 1.9-2.1, and the refractive index of the high-refraction layer is 1.6-1.7. According to the preferred scheme, light rays are injected into the first substrate layer from air to be refracted and reflected, the first substrate layer is injected into the first conductive layer to be refracted and reflected, the refraction is large, the reflection is small, the high-refraction layer with the refractive index of 1.6-1.7 is added between the first substrate layer and the first conductive layer, the transition effect is achieved, more light rays are refracted, reflection is reduced, after the first conductive layer is etched by laser, the first conductive layer is not etched at the cutting line, and therefore the refraction and reflection data of the light rays at the portion where the first substrate layer and the first conductive layer exist are similar to those of the portion where the first substrate layer exists but the first conductive layer does not exist are more similar, the laser etching cutting line is not obvious in vision, the purpose of further eliminating shadow on the etching cutting line is achieved, and meanwhile the partition yield is further improved.

The metal oxide layer or the metal fluoride may be a material which is conventional in the art in the case of satisfying the above refractive index, for example, the metal oxide layer may be alumina, magnesia, or the like, and the metal fluoride may be cerium fluoride, or the like.

In some preferred embodiments of the present invention, the first conductive layer is a non-crystalline conductive material, and the UV transmittance of the non-crystalline conductive material is > 50%. According to the preferred scheme, the first conductive layer is cut off more easily under the condition of low laser power, so that damage of laser to the first substrate layer, the PDLC layer and the second conductive layer is further reduced, and the line diameter width and the depth of a laser cutting line are reduced conveniently.

The materials and thicknesses of the first substrate layer, the second substrate layer, the first conductive layer, the second conductive layer and the PDLC layer in the invention can be corresponding materials and thicknesses in the prior art, for example, the first substrate layer and the second substrate layer can be PET, PE and the like, and the first conductive layer and the second conductive layer can be ITO and the like. For example, the second substrate layer may have a thickness of 100 to 200 μm, the second conductive layer may have a thickness of 20 to 50nm, and the PDLC layer may have a thickness of 10 to 25 μm.

The invention also provides a zoned PDLC film with invisible line of sight produced by the aforementioned production method. According to the partitioned PDLC film provided by the invention, due to the adoption of the preparation method, the structure of each layer is affected microscopically, so that each layer of the PDLC film is less damaged or affected, and the line diameter generated by other layers due to laser cutting is invisible under the visual condition.

The following detailed description of the embodiments of the invention is exemplary and is merely illustrative of the invention and not to be construed as limiting the invention.

Example 1

The preparation method of the sectional PDLC film with invisible visual line diameter comprises the steps of firstly preparing the PDLC film, wherein the PDLC film comprises a first substrate layer 1 (specifically PET), a first conductive layer 2, a PDLC layer 3, a second conductive layer 4 (specifically ITO) and a second substrate layer 5 (specifically PET) which are sequentially arranged, as shown in figure 1. The first conductive layer 2 is made of a non-crystalline conductive material (specifically, ITO), and the UV transmittance of the non-crystalline conductive material is greater than 50%. The thicknesses of the first substrate layer 1 and the second substrate layer 5 are 188 mu m, the thicknesses of the first conductive layer 2 and the second conductive layer 4 are 30nm, and the thickness of the PDLC layer 3 is 15 mu m.

A high refractive layer is further arranged between the first substrate layer 1 and the first conductive layer 2, the high refractive layer is alumina, the refractive index of the high refractive layer is 1.63, the refractive index of the first substrate layer 1 is about 1.57, the refractive index of the first conductive layer 2 is about 2.10, and the thickness of the high refractive layer is 3 μm.

Laser partitioning is then performed on the PDLC film, the process of laser partitioning comprising the steps of:

s1, placing a PDLC film on a negative pressure platform, and controlling the flatness of the negative pressure platform to be +/-0.02 mm;

s2, laser is emitted by an ultraviolet laser to penetrate through the first substrate layer 1, and the first conductive layer 2 is cut along a preset cutting path (2 paths are divided into three areas uniformly), wherein the light spot of the laser is controlled to deviate from the first conductive layer 2 and is focused on a part of the first substrate layer 1 close to the first conductive layer 2, so that only the first conductive layer 2 positioned on one side of the PDLC layer 3 is etched; controlling the light spot deviation distance of the laser so that the line width of the etching cutting line cut by the laser on the first conductive layer 2 is 44-46 mu m; the distance between the ultraviolet laser and the PDLC film is measured through the height indicator, and the height of the ultraviolet laser is adjusted in real time according to the distance, so that the light spot deviation distance of laser is ensured. And the conditions for the laser cutting include: the laser wavelength is 330-380nm, the power is 0.4w, the cutting speed is 60mm/s, and the light spot is 20 mu m.

Then pulse laser focusing treatment is carried out on the inside of the first substrate layer 1 to form a dodging area 6 parallel to a preset cutting path; the dodging area 6 is located at one side of the laser cut light spot focusing area 7 far away from the first conductive layer 2, and the width of the dodging area 6 is not smaller than the line width of the etching cutting line on the first conductive layer 2. The distance d between the dodging area 6 and the light spot focusing area 7 is controlled to be 40 mu m; the width D of the light homogenizing zone 6 is 70 μm.

Wherein the conditions of the pulsed laser focusing process include: ultraviolet laser is adopted, the laser wavelength is 330-380nm, the power is 0.3w, the processing speed is 100mm/s, the light spots after laser focusing are 8 mu m, and the interval between the light spots after laser focusing is 2.0 times of the light spots after laser focusing in pulse processing.

S3, eliminating a heat affected zone at an etching line of the PDLC layer through baking and cooling; the baking includes: the low-temperature heating section is firstly carried out and the conditions include: the temperature is 120 ℃ and the time is 10min; the high temperature heating section is carried out again and the conditions include: the temperature was 140℃and the time was 5min.

Example 2

The method according to example 1 was performed with the difference that the spot deviation distance of the laser was controlled so that the line width of the etched cutting line cut by the laser on the first conductive layer was 58-60 μm.

Example 3

The method according to example 1 was performed with the difference that the spot deviation distance of the laser was controlled so that the line width of the etched cutting line cut by the laser on the first conductive layer was 28 to 30 μm.

Example 4

The method of example 1 was performed, except that the pulsed laser focusing treatment was not performed in S2, and no light homogenizing region was formed; but directly after laser cutting S3.

Example 5

The method of example 1 was performed with the difference that the power of the pulsed laser focusing treatment was changed to be the same as that of the laser cutting.

Example 6

The method of example 1 was performed with the difference that the processing speed of the pulsed laser focusing processing was changed to be the same as the cutting speed of laser cutting.

Example 7

The method of example 1 was performed with the difference that the post-focusing laser spot of the pulsed laser focusing treatment was changed to be the same as the laser spot of the laser cutting.

Example 8

The method of example 1 was performed with the difference that the interval between spots after focusing of adjacent lasers was 1 time as large as that of the spots after focusing of the lasers in the pulsed laser focusing treatment.

Example 9

The procedure of example 1 was followed, except that the distance d between the dodging zone and the spot focusing area was 20. Mu.m.

Example 10

The method of example 1 was performed with the difference that the width D of the light homogenizing zone was the same as the line width of the etched scribe line on the first conductive layer.

Example 11

The procedure of example 1 was followed, except that the temperature of S3 baking was 145 ℃.

Example 12

The procedure of example 1 was followed, except that the high refractive layer was not provided.

Example 13

The process according to example 1 was carried out, except that the low-temperature heating stage was not carried out but only the high-temperature heating stage was carried out in the baking as described in S3.

Comparative example 1

The method of example 1 was performed with the difference that the laser spot was not deviated but focused on the first conductive layer with the conventional laser cutting, and the conditions of the laser cutting were unchanged.

Comparative example 2

The process of example 1 was followed except that the baking of S3 was not performed.

Comparative example 3

The procedure of example 1 was followed, except that the power of laser cutting was changed to 0.7w.

Test case

The inter-engraved-area PDLC films obtained in the above examples and comparative examples were subjected to various performance tests including the visible condition of traces caused by laser cutting, the area yield, whether or not a heat affected zone exists in the PDLC layer, and the results are shown in table 1.

The visible conditions are divided into: visible and invisible under natural light, visible and invisible under visual observation of the light source. The visual observation method of the light source comprises the following steps: and placing an LED white light lamp behind the diaphragm of the PDLC film to be tested, wherein the illumination intensity of the diaphragm which is 1m away from the PDLC film is 2000-3000 Lux.

The method for testing the partition yield comprises the following steps: the partitioned PDLC films obtained in the examples and the comparative examples were produced in batch, and statistics was performed on the products capable of achieving the partitioned dimming in the batch, where the portion where the partitioned dimming could not be achieved may be the failure of the partitioned dimming function due to incomplete laser cutting (i.e., incomplete cutting) or the cutting of the collinear ITO film caused by the failure of the second conductive layer by the penetration of laser energy through the PDLC layer, and the electric field could not be transmitted from the collinear electrode to the entire PDLC film.

The testing method for the existence of the heat affected zone of the PDLC layer comprises the following steps: the partitioned etched lines were observed at 100-300 times magnification using a microscope.

TABLE 1

Compared with the comparative example, the embodiment of the invention can make the laser etching partition line of the obtained partitioned PDLC film invisible visually, is easy to cut by laser, has no surface pollution, can realize the dimming function, has minimum damage to the PDLC layer by laser cutting, and improves the partition yield.

Further, according to embodiment 1 and embodiments 2 to 13, by adopting the scheme of the preferred control process of the present invention, the visual degree of the etching line under visual observation can be further reduced on the basis of the visual invisibility of the etching line, and the improvement of the partition yield can be more facilitated.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims

1. A method for preparing a sectional PDLC film with invisible visual line diameter comprises preparing PDLC film, and then performing laser sectional operation on the PDLC film; the PDLC film comprises a first protective film layer, a first substrate layer, a first conductive layer, a PDLC layer, a second conductive layer, a second substrate layer and a second protective film layer which are sequentially arranged; the method is characterized in that the laser partitioning process comprises the following steps:

s2, laser is emitted by an ultraviolet laser to penetrate the first substrate layer, and laser cutting is conducted on the first conductive layer along a preset cutting path, wherein a light spot of the laser is controlled to deviate from the first conductive layer and is focused on a part of the first substrate layer close to the first conductive layer, and only the first conductive layer located on one side of the PDLC layer is etched; and the conditions for the laser cutting include: the laser wavelength is 330-380nm, the power is 0.2-0.8W, the cutting speed is 50-120mm/s, and the light spot is 15-25 μm; the light spot deviation distance of the laser is controlled, so that the line width of an etching cutting line cut by the laser on the first conductive layer is less than or equal to 60 mu m;

after the laser cutting in the S2, pulse laser focusing treatment is further carried out on the inner part of the first substrate layer, so that a dodging area parallel to a preset cutting path is formed; the light homogenizing region is positioned on one side of the light spot focusing region of the laser cutting, which is far away from the first conductive layer, and the width of the light homogenizing region is not smaller than the line width of the etching cutting line on the first conductive layer;

and S3, eliminating a heat affected zone at the etched line of the PDLC layer through baking and cooling.

2. The method for producing a segmented PDLC film invisible according to claim 1, wherein said baking conditions comprise: the temperature is 100-148 ℃, and the time is 10-30min.

3. The method for producing a segmented PDLC film with invisible line of sight according to claim 1, wherein in S2, the spot deviation distance of said laser is controlled such that the line width of the etched cutting line cut by the laser on the first conductive layer is 35-60 μm.

4. The method for producing a segmented PDLC film invisible according to claim 1, wherein conditions of said pulsed laser focusing treatment comprise: the laser wavelength is 330-380nm, the power is 0.3-0.4W and is less than the laser cutting power, the processing speed is 70-140mm/s and is greater than the cutting speed of laser cutting, the light spots after laser focusing are 5-10 mu m, and the interval between the light spots after laser focusing adjacent to the pulse processing is more than 1.3 times of the light spots after laser focusing.

5. The method for producing a segmented PDLC film with invisible line of sight according to claim 4, wherein the thickness of said first base material layer is 100-200 μm, and the distance d between the dodging region and the spot focusing region is controlled to be 35-50 μm;

and/or the number of the groups of groups,

the width D of the dodging zone is 70-110 mu m.

6. The method of producing a segmented PDLC film invisible according to claim 1, wherein said laser segmentation process further comprises: in S2, the distance between the ultraviolet laser and the PDLC film is measured through the altimeter, and the height of the ultraviolet laser is adjusted in real time according to the distance, so that the light spot deviation distance of laser is ensured.

7. The method for producing a segmented PDLC film invisible according to claim 2, wherein said baking conditions in S3 comprise:

the low-temperature heating section is firstly carried out and the conditions include: the temperature is 100-135 ℃ and the time is 10-23min;

the high temperature heating section is carried out again and the conditions include: the temperature is 136-145 ℃ and the time is 3-7min.

8. The method for producing a segmented PDLC film invisible according to claim 1, wherein said producing a PDLC film further comprises: the high-refraction layer is arranged between the first substrate layer and the first conductive layer, the high-refraction layer is metal oxide or metal fluoride, the refractive index of the first substrate layer is 1.45-1.57, the refractive index of the first conductive layer is 1.9-2.1, the refractive index of the high-refraction layer is 1.6-1.7, the thickness of the high-refraction layer is 2-8 mu m, and the thickness of the first conductive layer is 20-50nm.

9. The method of producing a segmented PDLC film with invisible line of sight according to claim 1, wherein said first conductive layer is a non-crystalline conductive material, and UV transmittance of said non-crystalline conductive material is > 50%.

10. A segmented PDLC film not visible in visual line diameter, characterized by being produced by the production method of a segmented PDLC film not visible in visual line diameter according to any of claims 1-9.