PDLC (Polymer Dispersed Liquid Crystal) dimming film capable of displaying patterns in electric control manner and laser etching preparation method of PDLC dimming film

Abstract

The invention relates to a PDLC (polymer dispersed liquid crystal) dimming film capable of displaying patterns in an electric control manner and a laser etching preparation method of the PDLC dimming film. The PDLC dimming film comprises a first substrate layer, a first conductive layer, a first orientation layer, a polymer dispersed liquid crystal layer, a second orientation layer, a second conductive layer and a second substrate layer which are sequentially stacked, the first substrate layer and the first conductive layer protrude at the first side end of the PDLC dimming film to form a first protruding part, and the second substrate layer and the second conductive layer protrude at the second side end of the PDLC dimming film to form a second protruding part; the first conductive layer and the second conductive layer are correspondingly and respectively provided with at least two parting lines extending from the first side end of the PDLC dimming film to the second side end of the PDLC dimming film; the first electrode is arranged between at least two adjacent segmentation lines on the first conductive layer of the first protruding part, and the second electrode is arranged between at least two adjacent segmentation lines on the second conductive layer of the second protruding part; the first alignment layer and the second alignment layer each contain a fluorescent whitening agent. The PDLC dimming film can save electricity and improve permeability.

Description

Technical Field

[0001] The invention relates to the field of dimming films, and in particular to a PDLC dimming film capable of electrically controlling display patterns and a laser etching preparation method thereof. Background Art

[0002] PDLC dimming film can be used as a material for architectural decoration and car roof decoration. At present, when manufacturers of PDLC dimming film ship, they usually ship PDLC rolls, and the length of each roll is generally 50 to 100 meters, and the longest can reach 1,000 meters, and the width ranges from 1.2 meters to 2.0 meters. When customers use the dimming film, they often need to cut the roll of dimming film into a certain size, make electrodes, stick it on the glass or laminate it between two layers of glass, and turn on the power to switch the entire piece between transparent and opaque. However, in actual use, this cannot meet the customer's requirements for a piece of dimming film to be partially transparent or opaque and to display patterns.

[0003] The prior art provides a method for displaying patterns in a dimming film. A laser etcher is used to etch away the conductive layer of the PDLC dimming film, and the two conductive layers of the dimming film are divided into several conductive areas. Electricity is supplied to different conductive areas through electrodes, so that transparent and opaque area adjustment control and pattern display control in any interval can be achieved. However, the ordinary PDLC dimming film obtained by this method is transparent when powered on and frosted when not powered on. For architectural decoration purposes, it is hoped that it will be transparent for a long time, which requires power supply investment and more electricity costs. Moreover, the existing PDLC dimming film has low permeability in the frosted or transparent state, and cannot be used as a light source, making it difficult for users to see objects clearly. Summary of the invention

[0004] In view of the shortcomings of the prior art, a first object of the present invention is to provide a PDLC dimming film that can electrically control the display pattern, and the PDLC dimming film can save electricity and increase transmittance.

[0005] The second object of the present invention is to provide a method for preparing the PDLC dimming film capable of electrically controlling display patterns.

[0006] To achieve the first objective of the present invention, the present invention provides a PDLC dimming film capable of electrically controlling a display pattern, comprising a first substrate layer, a first conductive layer, a first orientation layer, a polymer dispersed liquid crystal layer, a second orientation layer, a second conductive layer and a second substrate layer stacked in sequence, the PDLC dimming film further comprising a first electrode and a second electrode, the first substrate layer and the first conductive layer protrude relative to the first orientation layer, the polymer dispersed liquid crystal layer and the second orientation layer at a first side end of the PDLC dimming film to form a first protruding portion; the second substrate layer and the second conductive layer protrude relative to the first orientation layer, the polymer dispersed liquid crystal layer and the second orientation layer at a second side end of the PDLC dimming film to form a second protruding portion; the first conductive layer and the second conductive layer are respectively provided with at least two dividing lines extending from the first side end of the PDLC dimming film to the second side end of the PDLC dimming film, each dividing line separates the corresponding first conductive layer or the second conductive layer into mutually insulated conductive areas; the first electrode is provided between at least two adjacent dividing lines on the first conductive layer of the first protruding portion, and the second electrode is provided between at least two adjacent dividing lines on the second conductive layer of the second protruding portion; the first orientation layer and the second orientation layer respectively contain fluorescent whitening agents.

[0007] In some embodiments of the present invention, the first alignment layer and the second alignment layer contain polyimide respectively, and the amount of the fluorescent brightener is 0.01-0.05 wt % of the polyimide.

[0008] In some embodiments of the present invention, the fluorescent whitening agent is FP-127, with a fineness of ≥300 mesh and a purity of ≥99%.

[0009] In some embodiments of the present invention, the first alignment layer and the second alignment layer are respectively formed by doping polyamic acid with a fluorescent whitening agent, curing, and rubbing.

[0010] In some embodiments of the present invention, the polyamic acid adopts the polyimide solution PAA-4005 series produced by Changzhou Yaan New Materials Co., Ltd.

[0011] In some embodiments of the present invention, the viscosity of the polyamic acid at 30° C. is 400-1000 mPa·s.

[0012] In some embodiments of the present invention, the first alignment layer and the second alignment layer have a thickness of 3-15 μm respectively.

[0013] In some embodiments of the present invention, the first conductive layer and the second conductive layer are respectively ITO.

[0014] In some embodiments of the present invention, the dividing lines are etched lines obtained by laser etching.

[0015] In some embodiments of the present invention, the first substrate layer and the second substrate layer are PET respectively.

[0016] To achieve the second purpose of the present invention, the present invention also provides a laser etching preparation method for a PDLC dimming film with an electrically controllable display pattern according to any of the above schemes, which comprises the following steps: step 1: sputtering a conductive material target material into a base material to obtain a conductive film; step 2: coating an orientation material onto the conductive film to form an oriented conductive film with an orientation coating; step 3: heating the orientation coating to cure the orientation coating, and rubbing the surface of the cured orientation coating; step 4: coating a polymer dispersed liquid crystal material between two oriented conductive films, and curing with ultraviolet light to form a first base layer, a first conductive layer, a first orientation layer, a polymer dispersed liquid crystal layer, and a second orientation layer. , a second conductive layer and a second base layer stacked in sequence; step five: using a laser with a fixed focus to etch the first conductive layer and the second conductive layer of the intermediate product to form a dividing line; step six: cutting off the second orientation layer, the second conductive layer and the second base layer on the first side of the intermediate product, and using an organic solvent to wipe off the first orientation layer and the polymer dispersed liquid crystal layer on the first conductive layer to form a first protruding portion; cutting off the first orientation layer, the first conductive layer and the first base layer on the second side of the intermediate product, and using an organic solvent to wipe off the second orientation layer and the polymer dispersed liquid crystal layer on the second conductive layer to form a second protruding portion; step seven: making a first electrode on the first protruding portion, and making a second electrode on the second protruding portion.

[0017] In some embodiments of the present invention, the organic solvent is at least one of dimethyl sulfoxide, N-methylpyrrolidone, dimethylacetamide or tetrahydrofuran.

[0018] In some embodiments of the present invention, the heating temperature in step three is 80-280° C. and the heating time is 20-50 minutes.

[0019] To achieve the second purpose of the present invention, the present invention also provides another laser etching preparation method of the PDLC dimming film with an electrically controllable display pattern of any of the above schemes, which comprises the following steps: step 1: sputtering a conductive material target material into a base material to obtain a conductive film; step 2: coating an orientation material onto the conductive film to form an oriented conductive film with an orientation coating; step 3: heating the orientation coating to solidify the orientation coating, and rubbing the surface of the solidified orientation coating; step 4: coating a polymer dispersed liquid crystal material between two oriented conductive films, and using ultraviolet light to solidify to form a first base layer, a first conductive layer, and a first orientation layer. , a polymer dispersed liquid crystal layer, a second orientation layer, a second conductive layer and a second substrate layer stacked in sequence; step five: using a laser with a fixed focus to etch the first conductive layer and the second conductive layer of the intermediate product to form a dividing line; step six: scraping and removing the first orientation layer, the polymer dispersed liquid crystal layer, the second orientation layer, the second conductive layer and the second substrate layer on the first side of the intermediate product to form a first protruding portion; scraping and removing the second orientation layer, the polymer dispersed liquid crystal layer, the first orientation layer, the first conductive layer and the first substrate layer on the second side of the intermediate product to form a second protruding portion; step seven: making a first electrode on the first protruding portion and making a second electrode on the second protruding portion.

[0020] To achieve the second purpose of the present invention, the present invention also provides a laser etching preparation method for a PDLC dimming film with an electrically controllable display pattern according to any of the above schemes, which comprises the following steps: step 1: sputtering a conductive material target material into a base material to obtain a conductive film; step 2: coating an orientation material onto the conductive film to form an orientation conductive film with an orientation coating; step 3: performing a first heating operation on the orientation coating to partially cure the orientation coating, and rubbing the surface of the partially cured orientation coating; step 4: coating a polymer dispersed liquid crystal material between two orientation conductive films, curing with ultraviolet light, and forming a first base layer, a first conductive layer, a first orientation coating, a polymer dispersed liquid crystal layer, a second orientation coating, a second conductive layer, and a second base layer, which are stacked in sequence an intermediate product; step five: using a laser with a fixed focus to etch the first conductive layer and the second conductive layer of the intermediate product to form a dividing line; step six: scraping off the second orientation coating, the second conductive layer and the second base layer on the first side of the film obtained in step five, and using an organic solvent to wipe off the first orientation coating and the polymer dispersed liquid crystal layer on the first conductive layer to form a first protrusion; cutting off the first orientation layer, the first conductive layer and the first base layer on the second side of the intermediate product, and using an organic solvent to wipe off the second orientation coating and the polymer dispersed liquid crystal layer on the second conductive layer to form a second protrusion; step seven: performing a second heating operation on the film obtained in step six to completely cure the orientation coating; step eight: making a first electrode on the first protrusion and a second electrode on the second protrusion.

[0021] In some embodiments of the present invention, the organic solvent is ethanol or an ethanol-water solution.

[0022] In some embodiments of the present invention, the temperature of the first heating operation is higher than the temperature of the second heating operation.

[0023] In some embodiments of the present invention, the temperature of the first heating operation is 150-280° C., and the time is 10-30 minutes; the temperature of the second heating operation is 60-150° C., and the time is 20-30 minutes.

[0024] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0025] The PDLC dimming film of the present invention uses a dividing line, such as an etching line obtained by etching, to form upper and lower corresponding mutually insulated conductive areas on two conductive layers, so that the PDLC dimming film can display patterns and / or texts, and can also realize the adjustment and control of patterns and / or texts. The present invention also uses an orientation layer to form a reverse PDLC dimming film, so that the PDLC dimming film is transparent when not powered on and frosted when powered on. Especially for architectural decoration purposes, the PDLC dimming film can remain transparent for a long time without power, which can save more power supply investment and electricity costs. The present invention also adds a fluorescent brightener to the orientation layer to increase the transmittance by 3-10%. It can be used as a lighting device in the normal frosted state, and objects can be seen more clearly in the transparent state. Moreover, due to the doping of the fluorescent brightener, the dimming film has bright colors and a sense of technological fantasy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the cross-sectional structure of an embodiment of the PDLC dimming film of the present invention.

[0027] Figure 2 Schematic diagram of the conductive structure of the PDLC dimming film embodiment of the present invention.

[0028] In the figure, 1-first substrate layer, 2-first conductive layer, 3-first orientation layer, 4-polymer dispersed liquid crystal layer, 5-second orientation layer, 6-second conductive layer, 7-second substrate layer, 8-first electrode, 9-second electrode, 10-dividing line, 11-first protrusion, 12-second protrusion.

[0029] The present invention is further described in detail below with reference to the accompanying drawings and specific implementation modes. DETAILED DESCRIPTION

[0030] like Figures 1 to 2As shown, an embodiment of the present invention provides a PDLC dimming film that can electrically control the display of patterns. The PDLC dimming film can be used for architectural decoration and car decoration materials. It can display patterns and / or texts and control the display of patterns and / or texts, and remains frosted when powered on and remains transparent when powered off, thereby achieving long-term light transmission and saving electricity.

[0031] Specifically, the PDLC dimming film includes a first substrate layer 1, a first conductive layer 2, a first orientation layer 3, a polymer dispersed liquid crystal layer 4, a second orientation layer 5, a second conductive layer 6, and a second substrate layer 7 stacked in sequence. The first substrate layer 1, the first conductive layer 2, the first orientation layer 3, the polymer dispersed liquid crystal layer 4, the second orientation layer 5, the second conductive layer 6, and the second substrate layer 7 are adjacent to each other in sequence and stacked together to form a film-like structure.

[0032] The PDLC dimming film also includes a first electrode 8 and a second electrode 9, which are used to connect a power source. The first substrate layer 1 and the first conductive layer 2 protrude relative to the first orientation layer 3, the polymer dispersed liquid crystal layer 4 and the second orientation layer 5 at the first side end of the PDLC dimming film to form a first protruding portion 11, and the first conductive layer 2 is exposed on the first protruding portion 11 and is not covered by the first orientation layer 3, the polymer dispersed liquid crystal layer 4 and the second orientation layer 5. The first substrate layer 1 and the first conductive layer 2 may also protrude relative to the second conductive layer 6 and the second substrate layer 7 at the first side end of the PDLC dimming film, so that the first conductive layer 2 is not covered, which facilitates the arrangement of electrodes. Similarly, the second substrate layer 7 and the second conductive layer 6 protrude relative to the first orientation layer 3, the polymer dispersed liquid crystal layer 4 and the second orientation layer 5 at the second side end of the PDLC dimming film, and may also protrude relative to the first substrate layer 1 and the first conductive layer 2 to form a second protruding portion 12.

[0033] The PDLC dimming film of this embodiment uses an orientation layer to form a reverse dimming film, which is transparent without electricity and frosted with electricity. For architectural decoration purposes, it is hoped that it will be transparent for a long time. Compared with ordinary PDLC dimming films, this embodiment can save more power supply investment and electricity costs.

[0034] The first conductive layer 2 and the second conductive layer 6 are respectively provided with at least two dividing lines 10 extending from the first side end of the PDLC dimming film to the second side end of the PDLC dimming film. The first side end of the PDLC dimming film and the second side end of the PDLC dimming film can be two side ends that are opposite to each other or two side ends that are adjacent to each other. Each dividing line 10 separates the corresponding first conductive layer 2 or second conductive layer 6 into mutually insulated conductive areas. The dividing line 10 can be, for example, non-conductive, so that the conductive areas on both sides of the dividing line 10 are insulated and divided.

[0035] In some examples, any two dividing lines 10 do not intersect, so that the area between any two dividing lines 10 has the possibility of connecting to the power supply at both ends of the left and right sides of the dimming film, which is convenient for the design and control of images or texts. For example, the number of dividing lines 10 can be two, thereby dividing the conductive area into three, the number of dividing lines 10 can be three, thereby dividing the conductive area into four, the number of dividing lines 10 can be four, thereby dividing the conductive area into five, and so on.

[0036] The first electrode 8 is disposed between at least two adjacent dividing lines 10 on the first conductive layer 2 of the first protrusion 11, and the second electrode 9 is disposed between at least two adjacent dividing lines 10 on the second conductive layer 6 of the second protrusion 12, and is respectively used for power on / off control of at least one conductive area between the dividing lines 10 on the first conductive layer 2 and the second conductive layer 6, so as to achieve the switching of the frosted and transparent states of the patterns in different areas of the dimming film. For example, the multiple conductive areas divided by the dividing lines 10 can be alternately connected to electrodes and not connected to electrodes, and the multiple conductive areas divided by the dividing lines 10 can also be connected to electrodes. When the number of the first electrode 8 or the second electrode 9 is multiple, each first electrode 8 or the second electrode 9 can be independently controlled to be powered on and off, so as to achieve the control of the patterns in different areas, for example, the flexible change and combination of the patterns can be achieved. For example, as Figure 2 As shown, by different control schemes of the electrodes, various visual effects such as at least two rows of patterns being transparent at the same time, at least two rows of patterns being transparent alternately / sequentially, etc. can be achieved. By controlling each electrode to achieve visual effect design, increasing the number of rows of patterns can achieve more different visual effects. By optically controlling each independent conductive partition formed by the dividing line 10, the display capability of product patterns and texts can be improved with a small number of electrodes and a simple electrode control system.

[0037] The first alignment layer 3 and the second alignment layer 5 contain fluorescent brighteners respectively. Fluorescent brighteners are fluorescent dyes that can excite fluorescence when light is incident. Fluorescent brighteners can increase the light transmittance of the dimming film in a frosted or transparent state. In a frosted state, it can be used as a lighting device, and in a transparent state, objects can be seen more clearly. At the same time, the alignment layer is doped with fluorescent brighteners, and the color is bright, giving people a sense of fantasy brought by technology.

[0038] In some examples, the first orientation layer 3 and the second orientation layer 5 contain polyimide respectively, and the amount of fluorescent whitening agent is 0.01-0.05wt% of the polyimide. Polyimide as an orientation layer can make the liquid crystal material arranged in an orientation when not powered, so that the dimming film remains transparent when not powered. The fluorescent whitening agent can achieve a whitening effect with a small amount, and the transmittance of the dimming film can be greatly improved. The fluorescent whitening agent doped in polyimide with 0.01-0.05wt% can increase the transmittance of the dimming film by 3-10%.

[0039] In some examples, the fluorescent brightener is FP-127, with a fineness of ≥300 mesh and a purity of ≥99%. FP-127 (CAS NO. 40470-68-6) has good dispersibility in polyimide, good high temperature resistance and excellent light and weather resistance.

[0040] In some examples, the first alignment layer 3 and the second alignment layer 5 are respectively formed by doping polyamic acid with a fluorescent whitening agent, curing, and rubbing, so as to facilitate coating and molding of the alignment layer on the conductive layer.

[0041] In some examples, the polyamic acid adopts the polyimide solution PAA-4005 series produced by Changzhou Yaan New Materials Co., Ltd., which is a yellow transparent liquid.

[0042] In some examples, the viscosity of polyamic acid at 30° C. is 400 to 1000 mPa·s, which is convenient for coating.

[0043] In some examples, the first alignment layer 3 and the second alignment layer 5 have a thickness of 3 to 15 μm, respectively, which can obtain a good alignment function and facilitate molding. The thickness of the first alignment layer 3 and the thickness of the second alignment layer 5 can be 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, etc.

[0044] In some examples, the first conductive layer 2 and the second conductive layer 6 are respectively ITO, which has good conductivity and is easy to sputter.

[0045] In some examples, the first conductive layer 2 and the second conductive layer 6 have a thickness of 20-100 nm respectively, have good conductive properties and are easy to form.

[0046] In some examples, the dividing line 10 is an etched line obtained by laser etching. By etching on the conductive layer, the conductive layer is divided into a plurality of insulated and isolated conductive areas. Different conductive areas are used to display different patterns or texts.

[0047] In some examples, the width of the dividing line 10 is 5-20 μm, which is convenient for etching.

[0048] In some examples, the first substrate layer 1 and the second substrate layer 7 are respectively made of PET. PET has a stable structure, is easy to obtain raw materials, and has good transparency.

[0049] In some examples, the first substrate layer 1 and the second substrate layer 7 have a thickness of 100-400 μm respectively, so as to provide sufficient supporting strength.

[0050] In some examples, the polymer dispersed liquid crystal layer 4 has a thickness of 10-50 μm, which is thick enough to achieve the transition between the frosted state and the transparent state.

[0051] In some examples, the first protrusion 11 and the second protrusion 12 have a width of 0.5 to 20 mm respectively, which does not occupy too much area and facilitates electrode forming.

[0052] In some examples, the PDLC dimming film can be prepared by using a variety of laser etching methods, wherein the first method mainly includes the following steps:

[0053] Step 1: sputtering a conductive material target onto a substrate material to obtain a conductive film;

[0054] Step 2: coating the oriented material onto the conductive film to form an oriented conductive film with an oriented coating;

[0055] Step 3: heating the oriented coating to solidify the oriented coating, and rubbing the surface of the solidified oriented coating;

[0056] Step 4: coating the polymer dispersed liquid crystal material between the two oriented conductive films, and curing with ultraviolet light to form an intermediate product in which the first substrate layer 1, the first conductive layer 2, the first oriented layer 3, the polymer dispersed liquid crystal layer 4, the second oriented layer 5, the second conductive layer 6 and the second substrate layer 7 are sequentially stacked;

[0057] Step 5: Use a laser with a fixed focus to etch the first conductive layer 2 and the second conductive layer 6 of the intermediate product to form a dividing line 10;

[0058] Step 6: on the first side of the intermediate product, the second alignment layer 5, the second conductive layer 6, and the second base layer 7 are cut off, and the first alignment layer 3 and the polymer dispersed liquid crystal layer 4 on the first conductive layer 2 are wiped clean with an organic solvent to form a first protruding portion 11; on the second side of the intermediate product, the first alignment layer 3, the first conductive layer 2, and the first base layer 1 are cut off, and the second alignment layer 5 and the polymer dispersed liquid crystal layer 4 on the second conductive layer 6 are wiped clean with an organic solvent to form a second protruding portion 12;

[0059] Step 7: fabricate the first electrode 8 on the first protruding portion 11 , and fabricate the second electrode 9 on the second protruding portion 12 .

[0060] In some examples, the organic solvent may be at least one of dimethyl sulfoxide, N-methylpyrrolidone, dimethylacetamide or tetrahydrofuran, and the organic solvent can effectively remove the polymer dispersed liquid crystal material and polyimide by wiping.

[0061] In some examples, the heating temperature in step three is 80 to 280° C. and the heating time is 20 to 50 minutes, so that the polyamic acid is completely cured.

[0062] The preparation method has the advantages of simple steps and convenient operation. It mainly uses laser etching equipment to directly etch the PDLC dimming film, and prepares the PDLC dimming film with patterns and / or text according to the pre-designed product pattern and / or text display effect, which overcomes the shortcomings of the prior art of lengthy process, difficult operation, and low yield, and improves the operability of the preparation method. However, due to the poor solubility of the cured polyimide, a more soluble, more expensive and relatively more toxic solvent is required.

[0063] As an alternative example, the second laser etching preparation method of the PDLC dimming film includes the following steps:

[0064] Step 1: sputtering a conductive material target onto a substrate material to obtain a conductive film;

[0065] Step 2: coating the oriented material onto the conductive film to form an oriented conductive film with an oriented coating;

[0066] Step 3: heating the oriented coating to solidify the oriented coating, and rubbing the surface of the solidified oriented coating;

[0067] Step 4: coating the polymer dispersed liquid crystal material between the two oriented conductive films, and curing with ultraviolet light to form an intermediate product in which the first substrate layer 1, the first conductive layer 2, the first oriented layer 3, the polymer dispersed liquid crystal layer 4, the second oriented layer 5, the second conductive layer 6 and the second substrate layer 7 are sequentially stacked;

[0068] Step 5: Use a laser with a fixed focus to etch the first conductive layer 2 and the second conductive layer 6 of the intermediate product to form a dividing line 10;

[0069] Step 6: on the first side of the intermediate product, the first alignment layer 3, the polymer dispersed liquid crystal layer 4, the second alignment layer 5, the second conductive layer 6 and the second substrate layer 7 are removed by scraping to form a first protruding portion 11; on the second side of the intermediate product, the second alignment layer 5, the polymer dispersed liquid crystal layer 4, the first alignment layer 3, the first conductive layer 2 and the first substrate layer 1 are removed by scraping to form a second protruding portion 12;

[0070] Step 7: fabricate the first electrode 8 on the first protruding portion 11 , and fabricate the second electrode 9 on the second protruding portion 12 .

[0071] In some examples, the heating temperature in step three is 80 to 280° C. and the heating time is 20 to 50 minutes, so that the polyamic acid is completely cured.

[0072] This preparation method has the advantages of simple steps, and compared with the first preparation method mentioned above, the present invention omits the step of wiping with an organic solvent, and has fewer operation steps. However, the scraping and removal of the alignment layer requires relatively high process control, and scratches are easily formed on the surface of the conductive layer. Poor control can easily affect the formation of electrodes on the conductive layer.

[0073] As an alternative example, a third laser etching preparation method of a PDLC dimming film capable of electrically controlling a display pattern comprises the following steps:

[0074] Step 1: sputtering a conductive material target onto a substrate material to obtain a conductive film;

[0075] Step 2: coating the oriented material onto the conductive film to form an oriented conductive film with an oriented coating;

[0076] Step 3: performing a first heating operation on the oriented coating to partially solidify the oriented coating, and rubbing the surface of the partially solidified oriented coating;

[0077] Step 4: coating the polymer dispersed liquid crystal material between the two oriented conductive films, and curing with ultraviolet light to form an intermediate product in which the first substrate layer 1, the first conductive layer 2, the first oriented coating layer, the polymer dispersed liquid crystal layer 4, the second oriented coating layer, the second conductive layer 6 and the second substrate layer 7 are sequentially stacked;

[0078] Step 5: Use a laser with a fixed focus to etch the first conductive layer 2 and the second conductive layer 6 of the intermediate product to form a dividing line 10;

[0079] Step 6: on the first side of the film obtained in step 5, the second orientation coating, the second conductive layer 6 and the second base layer 7 are removed by scraping, and the first orientation coating and the polymer dispersed liquid crystal layer 4 on the first conductive layer 2 are wiped clean by an organic solvent to form a first protruding portion 11; on the second side of the intermediate product, the first orientation layer 3, the first conductive layer 2 and the first base layer 1 are removed, and the second orientation coating and the polymer dispersed liquid crystal layer 4 on the second conductive layer 6 are wiped clean by an organic solvent to form a second protruding portion 12;

[0080] Step 7: performing a second heating operation on the film obtained in step 6 to completely cure the oriented coating;

[0081] Step eight: fabricating a first electrode 8 on the first protruding portion 11 , and fabricating a second electrode 9 on the second protruding portion 12 .

[0082] In some examples, the organic solvent is ethanol or an ethanol-water solution.

[0083] In some examples, the temperature of the first heating operation is higher than the temperature of the second heating operation.

[0084] In some examples, the temperature of the first heating operation is 150-280°C, for example, 150-200°C, and the time is 10-30 minutes, for example, 20-30 minutes, so that the polyamic acid is mostly cured without affecting the substrate layer. The temperature of the second heating operation is 60-150°C, for example, 80-100°C, and the time is 20-30 minutes, so that the polyimide is completely cured.

[0085] Compared with the previous two preparation methods, this preparation method separates the polyimide alignment layer into two steps for curing. Although the second curing step is added, the preparation of the protrusion is more convenient, the solvent used is more environmentally friendly, and the molding quality of the conductive layer and the electrode is higher. Among them, the curing conditions of the first heating operation are controlled so that the solvent in the polyamic acid liquid is basically completely volatilized and most of the polyamic acid is cured to obtain an alignment layer with a fixed shape; the curing conditions of the second heating operation are controlled so that the polyamic acid is completely cured, so that the alignment layer is completely fixed. In the second heating operation, the amount of dehydration of the polyamic acid during curing is small, which does not affect the overall performance of the dimming film.

[0086] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0087] Example 1

[0088] In the PDLC dimming film of this embodiment, the first substrate layer 1 or the second substrate layer 7 is a PET film with a thickness of 130 μm. The first conductive layer 2 or the second conductive layer 6 is ITO with a thickness of 50 nm. The thickness of the polymer dispersed liquid crystal layer 4 is 30 μm. The width of the ITO layer connection area 11 is 0.8 mm. The width of the etching line is 10 μm. The PDLC dimming film capable of electrically controlling the display pattern is prepared by the following steps:

[0089] Step 1: Sputter the ITO target onto the PET film through a magnetic sputtering device to prepare a PET-ITO conductive film.

[0090] Step 2: The PAA-4005 polyamic acid solution containing FP-127 is coated on the roll PET-ITO conductive film by a roll-to-roll PI de-coating device. The viscosity of the solution is 500 mPa·s at 30° C. The amount of FP-127 is 0.05 wt% based on the mass of the polyimide formed by curing the polyamic acid.

[0091] Step 3: Heat the polyamic acid coating at a temperature of 200° C. for 20 minutes to cure most of the polyamic acid.

[0092] Step 4: Install the film on a PDLC dimming film coating machine, coat and cure the PDLC composition to prepare a PDLC dimming film; wherein the coating speed is set to 40 mm / s, and the UV curing power is adjusted to 3 mW / cm 2 .

[0093] Step 5: Use a laser etcher to laser etch the dimming film intermediate product prepared in step 4. The depth of the etching line is based on cutting the ITO conductive film. Etch multiple dividing lines in sequence. Repeat the operation to complete multiple rows of pattern etching. Among them, the PDLC dimming film is flatly fixed on a workbench with vacuum pores by vacuum adsorption; the solid / fiber laser used is 532nm type, and the laser head moves horizontally in the XY direction relative to the etching object; the specific etching operation is set as follows: the laser spot is focused on the ITO1 layer or ITO2 layer, and the vertical distance from the device base point is 110μm; the etching speed is 2200mm / s, the frequency is 180KHz, the pulse width is 38ns, and the point etching time is 0.02ms.

[0094] Step six: On the above-mentioned laser-etched PDLC dimming film, the second base layer 7, the second conductive layer 6 and the second orientation layer 5 with a width of 5 mm are cut off at the first side end, and the PDLC composition remaining on the first conductive layer 2 and the partially solidified material of the first orientation layer are wiped off using a 99.99% ethanol solution to form a first protrusion 11; similarly, the first base layer 1, the first conductive layer 2 and the first orientation layer 3 with a width of 5 mm are cut off at the second side end, and the PDLC composition remaining on the second conductive layer 6 and the partially solidified material of the second orientation layer are wiped off using a 99.99% ethanol solution to form a second protrusion 12.

[0095] Step 7: Heat the film obtained in step 6 at 80° C. for 20 minutes to completely solidify the alignment layer.

[0096] Step 8: Use screen printing to apply silver paste on the ITO layer on the first protrusion 11 and the second protrusion 12, and then use a hot air blower to dry the applied silver paste; stick a 5mm wide copper foil on the dried silver paste surface; repeat the above steps to complete the production of electrodes corresponding to all independent partitions of the ITO layer on both sides of the PDLC dimming film. Solder the lead wires on the surface of the copper foil produced above to complete the production of electrodes on the ITO layer.

[0097] The patterned area of ​​the PDLC dimming film obtained in this embodiment is frosted when powered on, with a visible light transmittance of 20% and a haze of 92%; and is transparent when powered off, with a visible light transmittance of 85% and a haze of 8%.

[0098] Example 2

[0099] The preparation method of the PDLC dimming film of this embodiment is basically the same as that of Example 1, except that the amount of FP-127 used is 0.01wt% based on the mass of the polyimide formed by curing the polyamic acid. The pattern area of ​​the PDLC dimming film obtained in this embodiment is frosted when powered on, with a visible light transmittance of 15% and a haze of 94%; it is transparent when powered off, with a visible light transmittance of 81% and a haze of 9%.

[0100] Example 3

[0101] The preparation method of the PDLC dimming film of this embodiment is basically the same as that of Example 1, except that the amount of FP-127 used is 0.1wt% based on the mass of the polyimide formed by curing the polyamic acid. The pattern area of ​​the PDLC dimming film obtained in this embodiment is frosted when powered on, with a visible light transmittance of 20% and a haze of 90%; it is transparent when powered off, with a visible light transmittance of 86% and a haze of 10%. It can be seen that the anti-transmittance effect is not significantly improved when the amount of fluorescent whitening agent used is increased relative to that of Example 1.

[0102] Comparative Example 1

[0103] The preparation method of the PDLC dimming film of this comparative example is basically the same as that of Example 1, except that no fluorescent whitening agent is used. The pattern area of ​​the PDLC dimming film obtained in this comparative example is frosted when powered on, with a visible light transmittance of 10% and a haze of 95%; it is transparent when powered off, with a visible light transmittance of 75% and a haze of 13%.

[0104] Finally, it should be emphasized that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A PDLC dimming film capable of electrically controlling a display pattern, comprising a first substrate layer, a first conductive layer, a first orientation layer, a polymer dispersed liquid crystal layer, a second orientation layer, a second conductive layer, and a second substrate layer stacked in sequence, the PDLC dimming film further comprising a first electrode and a second electrode, characterized in that: The first substrate layer and the first conductive layer protrude relative to the first alignment layer, the polymer dispersed liquid crystal layer and the second alignment layer at a first side end of the PDLC dimming film to form a first protruding portion; The second substrate layer and the second conductive layer protrude relative to the first alignment layer, the polymer dispersed liquid crystal layer and the second alignment layer at the second side end of the PDLC dimming film to form a second protruding portion; The first conductive layer and the second conductive layer are respectively provided with at least two dividing lines extending from the first side end of the PDLC dimming film to the second side end of the PDLC dimming film, and each of the dividing lines separates the corresponding first conductive layer or the second conductive layer into mutually insulated conductive areas; The first electrode is disposed between at least two adjacent dividing lines on the first conductive layer of the first protruding portion, and the second electrode is disposed between at least two adjacent dividing lines on the second conductive layer of the second protruding portion; The first alignment layer and the second alignment layer contain fluorescent whitening agents respectively.

2. The PDLC dimming film capable of electrically controlling display patterns according to claim 1, characterized in that The first alignment layer and the second alignment layer respectively contain polyimide, and the amount of the fluorescent brightener is 0.01 to 0.05 wt % of the polyimide; The fluorescent whitening agent is FP-127, with a fineness of ≥300 meshes and a purity of ≥99%.

3. The PDLC dimming film capable of electrically controlling display patterns according to claim 2, characterized in that The first alignment layer and the second alignment layer are respectively formed by doping polyamic acid with a fluorescent whitening agent, curing and rubbing; The polyamic acid adopts the polyimide solution PAA-4005 series produced by Changzhou Yaan New Materials Co., Ltd. The viscosity of the polyamic acid at 30° C. is 400 to 1000 mPa·s.

4. The PDLC dimming film capable of electrically controlling display patterns according to any one of claims 1 to 3, characterized in that The first alignment layer and the second alignment layer have a thickness of 3 to 15 μm respectively; The first conductive layer and the second conductive layer are ITO respectively; The dividing line is an etched line obtained by laser etching; The first substrate layer and the second substrate layer are PET respectively.

5. The laser etching preparation method of the PDLC dimming film capable of electrically controlling the display pattern according to any one of claims 1 to 4, characterized in that The following steps are involved: Step 1: sputtering a conductive material target onto a substrate material to obtain a conductive film; Step 2: coating the oriented material onto the conductive film to form an oriented conductive film with an oriented coating; Step 3: heating the oriented coating to solidify the oriented coating, and rubbing the surface of the solidified oriented coating; Step 4: coating the polymer dispersed liquid crystal material between the two oriented conductive films, and curing with ultraviolet light to form an intermediate product in which the first substrate layer, the first conductive layer, the first oriented layer, the polymer dispersed liquid crystal layer, the second oriented layer, the second conductive layer and the second substrate layer are sequentially stacked; Step 5: using a laser with a fixed focus to etch the first conductive layer and the second conductive layer of the intermediate product to form a dividing line; Step 6: cutting off the second alignment layer, the second conductive layer, and the second base layer on the first side of the intermediate product, and using an organic solvent to clean the first alignment layer and the polymer dispersed liquid crystal layer on the first conductive layer to form a first protrusion; cutting off the first alignment layer, the first conductive layer, and the first base layer on the second side of the intermediate product, and using an organic solvent to clean the second alignment layer and the polymer dispersed liquid crystal layer on the second conductive layer to form a second protrusion; Step 7: Making a first electrode on the first protruding portion, and making a second electrode on the second protruding portion.

6. The preparation method according to claim 5, characterized in that The organic solvent is at least one of dimethyl sulfoxide, N-methylpyrrolidone, dimethylacetamide or tetrahydrofuran; The heating temperature in step 3 is 80-280° C. and the heating time is 20-50 minutes.

7. The laser etching preparation method of the PDLC dimming film capable of electrically controlling the display pattern according to any one of claims 1 to 4, characterized in that The following steps are involved: Step 1: sputtering a conductive material target onto a substrate material to obtain a conductive film; Step 2: coating the oriented material onto the conductive film to form an oriented conductive film with an oriented coating; Step 3: heating the oriented coating to solidify the oriented coating, and rubbing the surface of the solidified oriented coating; Step 4: coating the polymer dispersed liquid crystal material between the two oriented conductive films, and curing with ultraviolet light to form an intermediate product in which the first substrate layer, the first conductive layer, the first oriented layer, the polymer dispersed liquid crystal layer, the second oriented layer, the second conductive layer and the second substrate layer are sequentially stacked; Step 5: using a laser with a fixed focus to etch the first conductive layer and the second conductive layer of the intermediate product to form a dividing line; Step 6: scraping and removing the first alignment layer, the polymer dispersed liquid crystal layer, the second alignment layer, the second conductive layer and the second substrate layer on the first side of the intermediate product to form a first protruding portion; scraping and removing the second alignment layer, the polymer dispersed liquid crystal layer, the first alignment layer, the first conductive layer and the first substrate layer on the second side of the intermediate product to form a second protruding portion; Step 7: Making a first electrode on the first protruding portion, and making a second electrode on the second protruding portion.

8. The laser etching preparation method of the PDLC dimming film capable of electrically controlling the display pattern according to any one of claims 1 to 4, characterized in that The following steps are involved: Step 1: sputtering a conductive material target onto a substrate material to obtain a conductive film; Step 2: coating the oriented material onto the conductive film to form an oriented conductive film with an oriented coating; Step 3: performing a first heating operation on the oriented coating so that the oriented coating is partially cured, and rubbing the surface of the partially cured oriented coating; Step 4: coating the polymer dispersed liquid crystal material between the two oriented conductive films, and curing with ultraviolet light to form an intermediate product in which a first substrate layer, a first conductive layer, a first oriented coating layer, a polymer dispersed liquid crystal layer, a second oriented coating layer, a second conductive layer and a second substrate layer are sequentially stacked; Step 5: using a laser with a fixed focus to etch the first conductive layer and the second conductive layer of the intermediate product to form a dividing line; Step 6: on the first side of the film obtained in step 5, the second orientation coating, the second conductive layer and the second base layer are removed by scraping, and the first orientation coating and the polymer dispersed liquid crystal layer on the first conductive layer are wiped clean by an organic solvent to form a first protrusion; on the second side of the intermediate product, the first orientation layer, the first conductive layer and the first base layer are removed by scraping, and the second orientation coating and the polymer dispersed liquid crystal layer on the second conductive layer are wiped clean by an organic solvent to form a second protrusion; Step 7: performing a second heating operation on the film obtained in step 6 so that the oriented coating is completely cured; Step eight: fabricating a first electrode on the first protruding portion, and fabricating a second electrode on the second protruding portion.

9. The preparation method according to claim 8, characterized in that The organic solvent is ethanol or ethanol-water solution; The temperature of the first heating operation is higher than the temperature of the second heating operation.

10. The preparation method according to claim 9, characterized in that The temperature of the first heating operation is 150-280° C., and the time is 10-30 minutes; the temperature of the second heating operation is 60-150° C., and the time is 20-30 minutes.

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