Electrically controllable display pattern PDLC light control film and its laser etching preparation method

Abstract

The present application relates to a PDLC light control film capable of displaying a pattern under electric control and a laser etching preparation method thereof, the PDLC light control film 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 which are stacked in sequence, the first substrate layer and the first conductive layer protruding at a first side end of the PDLC light control film to form a first protruding part, the second substrate layer and the second conductive layer protruding at a second side end of the PDLC light control film to form a second protruding part, the first conductive layer and the second conductive layer being respectively provided with at least two division lines extending from the first side end of the PDLC light control film to the second side end of the PDLC light control film in correspondence, the first electrode being arranged between at least two adjacent division lines on the first conductive layer of the first protruding part, and the second electrode being arranged between at least two adjacent division lines on the second conductive layer of the second protruding part, the first orientation layer and the second orientation layer each containing a fluorescent whitening agent. The PDLC light control film can save electricity and increase transmittance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of light-adjusting film, in particular to a PDLC light-adjusting film capable of displaying electrically-controlled patterns and a laser etching preparation method thereof. BACKGROUND

[0002] The PDLC light-adjusting film can be used as a material for building decoration and car roof decoration. At present, the PDLC light-adjusting film manufacturers generally deliver the PDLC roll, each roll having a length of 50-100 meters, a maximum length of 1000 meters, and a width of 1.2-2.0 meters. When the customer uses the light-adjusting film, the roll-shaped light-adjusting film is often cut into a certain size, an electrode is made thereon, and the light-adjusting film is pasted on the glass or laminated between two layers of glass to realize the whole transparent and opaque switching by power supply. However, this cannot meet the customer's requirements of part transparent or opaque and pattern display in a piece of light-adjusting film in actual use.

[0003] The prior art provides a method for displaying patterns in the light-adjusting film. The conductive layer of the PDLC light-adjusting film is etched by using a laser etching machine, the two conductive layers of the light-adjusting film are divided into several conductive areas, and different conductive areas are powered through electrodes, so that the transparent and opaque area adjustment control and pattern display control in any interval can be realized. However, the ordinary PDLC light-adjusting film obtained by this method is transparent when powered and is frosted when not powered, which is not transparent for a long time for building decoration, which needs to consume power supply investment and needs more power consumption. Moreover, the existing PDLC light-adjusting film has low transmittance in the frosted or transparent state, cannot be used as a light source, and is difficult for the user to see the object clearly. SUMMARY

[0004] In view of the deficiencies of the prior art, the first object of the present application is to provide a PDLC light-adjusting film capable of displaying electrically-controlled patterns, which can save power and increase transmittance.

[0005] The second object of the present application is to provide a preparation method of the PDLC light-adjusting film capable of displaying electrically-controlled patterns.

[0006] To achieve the first objective of this invention, the present invention provides a PDLC dimming film capable of electrically controlling the display of patterns, comprising a first substrate layer, a first conductive layer, a first alignment layer, a polymer-dispersed liquid crystal layer, a second alignment layer, a second conductive layer, and a second substrate layer stacked sequentially. The PDLC dimming film further includes a first electrode and a second electrode. The first substrate layer and the first conductive layer protrude from 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, forming a first protrusion. The second substrate layer and the second conductive layer protrude from the first alignment layer, the polymer-dispersed liquid crystal layer, and the second alignment layer at a second side end of the PDLC dimming film, forming a second protrusion. 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 separating the corresponding first conductive layer or second conductive layer into mutually insulated conductive regions. The first electrode is disposed between at least two adjacent dividing lines on the first conductive layer of the first protrusion, and the second electrode is disposed between at least two adjacent dividing lines on the second conductive layer of the second protrusion. The first alignment layer and the second alignment layer respectively contain a fluorescent whitening agent.

[0007] In some embodiments of the present invention, the first orientation layer and the second orientation layer each contain polyimide, and the amount of fluorescent whitening agent is 0.01 to 0.05 wt% of the polyimide.

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

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

[0010] In some embodiments of the present invention, the polyamic acid used is the polyimide solution PAA-4005 system from Changzhou Ya'an New Materials Co., Ltd.

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

[0012] In some embodiments of the present invention, the first orientation layer and the second orientation layer each have a thickness of 3 to 15 μm.

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

[0014] In some embodiments of the present invention, the dividing line is an etching line 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 objective of this invention, the present invention also provides a laser etching method for preparing a PDLC dimming film with an electrically controllable display pattern according to any of the above-mentioned schemes, comprising the following steps: Step 1: Sputtering conductive material targets onto a substrate material to obtain a conductive film; Step 2: Coating an alignment material onto the conductive film to form an alignment conductive film with an alignment coating; Step 3: Heating the alignment coating to cure it, and rubbing the surface of the cured alignment coating; Step 4: Coating a polymer-dispersed liquid crystal material between two alignment conductive films and curing it with ultraviolet light to form a first substrate layer, a first conductive layer, a first alignment layer, a polymer-dispersed liquid crystal layer, and a second alignment layer. Step 5: Using a laser to focus and etch the first and second conductive layers of the intermediate product to form a dividing line; Step 6: Cut off the second alignment layer, the second conductive layer and the second base layer on the first side of the intermediate product, and use 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; Cut off the first alignment layer, the first conductive layer and the first base layer on the second side of the intermediate product, and use 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: Fabricate a first electrode on the first protrusion and a second electrode on the second protrusion.

[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 objective of this invention, this invention also provides another laser etching method for preparing a PDLC dimming film with an electrically controllable display pattern according to any of the above-mentioned schemes, which includes the following steps: Step 1: Sputtering conductive material targets onto a substrate material to obtain a conductive film; Step 2: Coating an alignment material onto the conductive film to form an alignment conductive film with an alignment coating; Step 3: Heating the alignment coating to cure it, and rubbing the surface of the cured alignment coating; Step 4: Coating a polymer-dispersed liquid crystal material between two alignment conductive films and curing it with ultraviolet light to form a first substrate layer, a first conductive layer, and a first alignment layer. Step 5: An intermediate product consisting of a polymer-dispersed liquid crystal layer, a second alignment layer, a second conductive layer, and a second base layer stacked sequentially; Step 6: Using a laser with fixed focus, etching is performed on the first and second conductive layers of the intermediate product to form dividing lines; Step 7: The first alignment layer, polymer-dispersed liquid crystal layer, second alignment layer, second conductive layer, and second base layer are removed from the first side of the intermediate product to form a first protrusion; The second alignment layer, polymer-dispersed liquid crystal layer, first alignment layer, first conductive layer, and first base layer are removed from the second side of the intermediate product to form a second protrusion; Step 8: A first electrode is fabricated on the first protrusion, and a second electrode is fabricated on the second protrusion.

[0020] To achieve the second objective of this invention, this invention also provides a laser etching method for preparing a PDLC dimming film with an electrically controllable display pattern according to any of the above-mentioned schemes, comprising the following steps: Step 1: Sputtering conductive material targets onto a substrate material to obtain a conductive film; Step 2: Coating an alignment material onto the conductive film to form an alignment conductive film with an alignment coating; Step 3: Performing a first heating operation on the alignment coating to partially solidify the alignment coating, and rubbing the surface of the partially solidified alignment coating; Step 4: Coating a polymer-dispersed liquid crystal material between two alignment conductive films and curing it with ultraviolet light to form a first substrate layer, a first conductive layer, a first alignment coating, a polymer-dispersed liquid crystal layer, a second alignment coating, a second conductive layer, and a second substrate layer stacked sequentially. The intermediate product; Step 5: Using a laser to focus and etch the first conductive layer and the second conductive layer of the intermediate product to form a dividing line; Step 6: Cut and scrape off the second alignment coating, the second conductive layer and the second base layer on the first side of the film obtained in Step 5, and use an organic solvent to clean the first alignment coating and the polymer-dispersed liquid crystal layer on the first conductive layer to form a first protrusion; Cut off the first alignment layer, the first conductive layer and the first base layer on the second side of the intermediate product, and use an organic solvent to clean the second alignment coating and the polymer-dispersed liquid crystal layer on the second conductive layer to form a second protrusion; Step 7: Perform a second heating operation on the film obtained in Step 6 to completely cure the alignment coating; Step 8: Fabricate 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 this invention uses etched lines, such as those obtained through etching, to form corresponding, mutually insulated conductive regions on two conductive layers. This allows the PDLC dimming film to display patterns and / or text, and also enables adjustment and control of these patterns and / or text. This invention also utilizes an alignment layer to form a reverse PDLC dimming film, making the PDLC dimming film transparent when not powered and frosted when powered. Particularly for architectural decoration applications, the PDLC dimming film can remain transparent for extended periods without power, saving on power supply investment and electricity costs. Furthermore, this invention adds a fluorescent whitening agent to the alignment layer, increasing transparency by 3-10%. In its normal frosted state, it can be used as a lighting device; in its transparent state, objects are clearly visible. Due to the addition of the fluorescent whitening agent, the dimming film has vibrant colors and a futuristic, dreamlike quality. Attached Figure Description

[0026] Fig. 1 This is a cross-sectional structural schematic diagram of an embodiment of the PDLC dimming film of the present invention.

[0027] Fig. 2 This is a schematic diagram of the conductive structure in an embodiment of the PDLC dimming film of the present invention.

[0028] In the figure, 1-first substrate layer, 2-first conductive layer, 3-first alignment layer, 4-polymer dispersed liquid crystal layer, 5-second alignment 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 will be further described in detail below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0030] like Figs. 1-2As shown, an embodiment of the present invention provides a PDLC dimming film that can electrically control the display of patterns. This PDLC dimming film can be used as a building decoration material and a car decoration material. It can display patterns and / or text and control the display of patterns and / or text. It remains frosted when powered on and transparent when powered off, enabling long-term light transmission and saving energy.

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

[0032] The PDLC dimming film also includes a first electrode 8 and a second electrode 9, which are used to connect to a power source. The first substrate layer 1 and the first conductive layer 2 protrude from the first alignment layer 3, the polymer-dispersed liquid crystal layer 4, and the second alignment layer 5 at the first side end of the PDLC dimming film, forming a first protrusion 11. The first conductive layer 2 is exposed on the first protrusion 11 and is not covered by the first alignment layer 3, the polymer-dispersed liquid crystal layer 4, and the second alignment layer 5. The first substrate layer 1 and the first conductive layer 2 may also protrude from 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, facilitating electrode placement. Similarly, the second substrate layer 7 and the second conductive layer 6 protrude from the first alignment layer 3, the polymer-dispersed liquid crystal layer 4, and the second alignment layer 5 at the second side end of the PDLC dimming film, and may also protrude from the first substrate layer 1 and the first conductive layer 2, forming a second protrusion 12.

[0033] This embodiment of the PDLC dimming film uses an alignment layer to form a reverse dimming film. It is transparent when not powered and frosted when powered. For architectural decoration applications, long-term transparency is desired. Compared with ordinary PDLC dimming films, this embodiment can save more on 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 and the second side end of the PDLC dimming film can be two side ends that are opposite to each other, or they can be 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 regions. The dividing line 10 can be, for example, non-conductive, so that the conductive regions on both sides of the dividing line 10 are separated by insulation.

[0035] In some examples, any two dividing lines 10 do not intersect, making it possible for the area between any two dividing lines 10 to be connected to a power source at both ends of the dimming film, facilitating the design and control of images or text. For example, the number of dividing lines 10 can be two, thus dividing the conductive area into three; the number of dividing lines 10 can be three, thus dividing the conductive area into four; the number of dividing lines 10 can be four, thus 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. These electrodes are used to control the on / off state of at least one conductive region between the dividing lines 10 on the first and second conductive layers 2 and 6, respectively, thereby achieving the switching between frosted and transparent states of the pattern in different regions of the dimming film. For example, multiple conductive regions divided by the dividing lines 10 can be alternately connected to electrodes and not connected to electrodes, or all multiple conductive regions divided by the dividing lines 10 can be connected to electrodes. When there are multiple first electrodes 8 or second electrodes 9, each first electrode 8 or second electrode 9 can be independently controlled to control the on / off state, thereby achieving control of the pattern in different regions, such as enabling flexible changes and combinations of patterns. For example, as... Fig. 2 As shown, by using different control schemes for the electrodes, various visual effects can be achieved, such as at least two rows of patterns being transparent simultaneously, or at least two rows of patterns being transparent alternately / sequentially. Visual effects can be designed by controlling each electrode, and increasing the number of rows of patterns can achieve even more diverse visual effects. By optically controlling the independent conductive zones formed by the dividing lines 10, the ability to display product patterns and text 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 each contain optical brighteners. Optical brighteners are fluorescent dyes that can fluoresce when light is incident. Optical brighteners can increase the light transmittance of the dimming film in either frosted or transparent states. In its frosted state, it can be used as a light-collecting device, while in its transparent state, objects are seen more clearly. At the same time, the alignment layers, due to the presence of optical brighteners, have vibrant colors, giving them a futuristic and dreamlike feel.

[0038] In some examples, the first alignment layer 3 and the second alignment layer 5 each contain polyimide, and the amount of fluorescent whitening agent is 0.01–0.05 wt% of the polyimide. As an alignment layer, the polyimide enables the liquid crystal material to align in the correct orientation when no current is applied, thus allowing the dimming film to remain transparent when no current is applied. A small amount of fluorescent whitening agent is sufficient to achieve a whitening effect, significantly improving the transmittance of the dimming film. Doping the polyimide with 0.01–0.05 wt% fluorescent whitening agent can increase the transmittance of the dimming film by 3–10%.

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

[0040] In some examples, the first orientation layer 3 and the second orientation layer 5 are respectively formed by doping polyamic acid with fluorescent whitening agent and curing and rubbing, which facilitates the coating and forming of the orientation layer on the conductive layer.

[0041] In some examples, the polyamic acid used is the PAA-4005 series polyimide solution from Changzhou Ya'an New Materials Co., Ltd., which is a yellow transparent liquid.

[0042] In some examples, polyamic acid has a viscosity of 400–1000 mPa·s at 30°C, which facilitates coating.

[0043] In some examples, the first orientation layer 3 and the second orientation layer 5 each have a thickness of 3–15 μm, which provides good orientation functionality and facilitates molding. The thicknesses of the first orientation layer 3 and the second orientation 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 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 to 100 nm, respectively, which have good conductivity 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, multiple conductive regions are obtained that divide the conductive layer into insulating and isolated regions. Different conductive regions are used to display different patterns or text.

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

[0048] In some examples, the first substrate 1 and the second substrate 7 are both PET. PET has a stable structure, readily available raw materials, and good transparency.

[0049] In some examples, the first substrate 1 and the second substrate 7 have a thickness of 100–400 μm, respectively, to provide sufficient support strength.

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

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

[0052] In some examples, the above-mentioned PDLC dimming film can be prepared using various laser etching methods, the first of which mainly includes the following steps:

[0053] Step 1: Sputter conductive material targets onto the substrate material to obtain conductive films;

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

[0055] Step 3: Heat the orientation coating to cure it, and then rub the surface of the cured orientation coating.

[0056] Step 4: Coat the polymer-dispersed liquid crystal material between the two oriented conductive films and cure it with ultraviolet light to form an intermediate product in which 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 stacked in sequence.

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

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

[0059] Step 7: Fabricate the first electrode 8 in the first protrusion 11 and the second electrode 9 in the second protrusion 12.

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

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

[0062] This preparation method has advantages such as simple steps and convenient operation. It mainly uses laser etching equipment to directly etch the PDLC dimming film, preparing a PDLC dimming film with patterns and / or text according to the pre-designed product pattern and / or text display effect. This overcomes the shortcomings of existing technologies, such as lengthy processes, difficult operation, and low yield, thus improving the operability of the preparation method. However, due to the decreased solubility of the cured polyimide, it is necessary to use solvents with higher solubility, higher cost, and relatively higher toxicity.

[0063] As an alternative example, the second laser etching method for preparing PDLC dimming films includes the following steps:

[0064] Step 1: Sputter conductive material targets onto the substrate material to obtain conductive films;

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

[0066] Step 3: Heat the orientation coating to cure it, and then rub the surface of the cured orientation coating.

[0067] Step 4: Coat the polymer-dispersed liquid crystal material between the two oriented conductive films and cure it with ultraviolet light to form an intermediate product in which 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 stacked in sequence.

[0068] Step 5: Use a laser to focus and etch the first conductive layer 2 and the second conductive layer 6 of the intermediate product to form the 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 base layer 7 are cut and scraped away to form the first protrusion 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 base layer 1 are cut and scraped away to form the second protrusion 12.

[0070] Step 7: Fabricate the first electrode 8 in the first protrusion 11 and the second electrode 9 in the second protrusion 12.

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

[0072] This preparation method has advantages such as simple steps. Compared with the first preparation method mentioned above, this invention omits the step of wiping with organic solvents, resulting in fewer operation steps. However, the removal of the alignment layer by cutting and scraping requires 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 method for laser etching to prepare a PDLC dimming film with an electrically controllable display pattern includes the following steps:

[0074] Step 1: Sputter conductive material targets onto the substrate material to obtain conductive films;

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

[0076] Step 3: Perform the first heating operation on the orientation coating to partially cure the orientation coating, and then rub the surface of the partially cured orientation coating.

[0077] Step 4: Coat the polymer-dispersed liquid crystal material between the two oriented conductive films and cure it 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 stacked in sequence.

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

[0079] Step 6: On the first side of the film obtained in Step 5, the second alignment coating, the second conductive layer 6, and the second base layer 7 are cut and scraped off, and the first alignment coating and polymer-dispersed liquid crystal layer 4 on the first conductive layer 2 are wiped clean with an organic solvent to form the first protrusion 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 coating and polymer-dispersed liquid crystal layer 4 on the second conductive layer 6 are wiped clean with an organic solvent to form the second protrusion 12;

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

[0081] Step 8: Fabricate the first electrode 8 in the first protrusion 11 and the second electrode 9 in the second protrusion 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, for 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, for 20–30 minutes, so that the polyimide is completely cured.

[0085] Compared to the previous two preparation methods, this method cures the polyimide alignment layer in two steps. Although this adds a second curing step, it makes the preparation of the protrusions easier, uses a more environmentally friendly solvent, and results in higher molding quality for the conductive layer and electrodes. Specifically, controlling the curing conditions of the first heating operation ensures that the solvent in the polyamic acid liquid evaporates almost completely, and the polyamic acid is largely cured, resulting in an alignment layer with a fixed shape. Controlling the curing conditions of the second heating operation ensures that the polyamic acid is completely cured, resulting in a fully shaped alignment layer. The second heating operation involves minimal dehydration of the polyamic acid during curing, 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 polymer-dispersed liquid crystal layer 4 has a thickness of 30 μm. The ITO layer connection area 11 has a width of 0.8 mm. The etching line width is 10 μm. This electrically controllable display pattern PDLC dimming film is prepared through the following steps:

[0089] Step 1: Using a magnetic sputtering device, ITO target material is sputtered onto a PET film to prepare a PET-ITO conductive film.

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

[0091] Step 3: Heat the polyamic acid coating at 200℃ for 20 minutes to allow most of the polyamic acid to cure.

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

[0093] Step 5: Use a laser etching machine to laser etch the intermediate product of the dimming film prepared in Step 4. The etching line depth is determined by cutting through the ITO conductive film. Multiple dividing lines are etched sequentially. Repeat the operation to complete the etching of multiple rows of patterns. Specifically, a vacuum adsorption method is used to flatten and fix the PDLC dimming film on a worktable with distributed vacuum micro-holes. A 532nm solid-state / fiber laser is used, and the laser head moves horizontally in the XY direction relative to the etched object. The specific etching operation settings are: the laser spot is fixed on the ITO1 or ITO2 layer, with a vertical distance of 110μm from the equipment base point; the etching speed is 2200mm / s, the frequency is 180KHz, the pulse width is 38ns, and the spot etching time is 0.02ms.

[0094] Step Six: On the laser-etched PDLC dimming film, a 5mm wide second base layer 7, second conductive layer 6, and second alignment layer 5 are cut off from the first side end. Using a 99.99% ethanol solution, the PDLC composition remaining on the first conductive layer 2 and part of the cured material of the first alignment layer are wiped clean to form the first protrusion 11. Similarly, a 5mm wide first base layer 1, first conductive layer 2, and first alignment layer 3 are cut off from the second side end. Using a 99.99% ethanol solution, the PDLC composition remaining on the second conductive layer 6 and part of the cured material of the second alignment layer are wiped clean to form the 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: Apply silver paste to the ITO layer using screen printing on the first protrusion 11 and the second protrusion 12, then dry the coated silver paste using a hot air blower. Place a 5mm wide copper foil onto the dried silver paste surface. Repeat the above steps to complete the fabrication of electrodes corresponding to all independent ITO layer sections on both sides of the PDLC dimming film. Solder leads onto the copper foil surface to complete the electrode fabrication of the ITO layer.

[0097] The patterned area of ​​the PDLC dimming film obtained in this embodiment is in a frosted state when powered on, with a visible light transmittance of 20% and a haze of 92%; and in a transparent state 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 in this embodiment is basically the same as that in Example 1, except that the amount of FP-127 used is 0.01 wt% based on the mass ratio of the polyimide formed by the curing of polyamic acid. The patterned 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 in this embodiment is basically the same as that in Example 1, except that the amount of FP-127 is 0.1 wt% based on the mass of the polyimide formed by curing polyamic acid. 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 90%; it is transparent when powered off, with a visible light transmittance of 86% and a haze of 10%. It is evident that increasing the amount of fluorescent whitening agent compared to Example 1 does not significantly improve the anti-reflection effect.

[0102] Comparative Example 1

[0103] The preparation method of the PDLC dimming film in this comparative example is basically the same as that in Example 1, except that no fluorescent whitening agent is used. The patterned 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 merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser etching method for fabricating a PDLC dimming film with an electrically controllable display pattern, wherein the fabricated PDLC dimming film with an electrically controllable display pattern comprises a first substrate layer, a first conductive layer, a first alignment layer, a polymer-dispersed liquid crystal layer, a second alignment layer, a second conductive layer, and a second substrate layer stacked sequentially, and the PDLC dimming film further comprises a first electrode and a second electrode, characterized in that, The first substrate layer and the first conductive layer protrude from the first alignment layer, the polymer-dispersed liquid crystal layer and the second alignment layer at the first side end of the PDLC dimming film, forming a first protrusion; the second substrate layer and the second conductive layer protrude from 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, forming a second protrusion; 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 dividing line separates the corresponding first conductive layer or second conductive layer into mutually insulated conductive regions; The first electrode is disposed between at least two adjacent dividing lines on the first conductive layer of the first protrusion, and the second electrode is disposed between at least two adjacent dividing lines on the second conductive layer of the second protrusion; the first alignment layer and the second alignment layer respectively contain fluorescent whitening agents; The laser etching preparation method is characterized by comprising the following steps: Step 1: Sputter conductive material targets onto the substrate material to obtain conductive films; Step 2: Coat the orientation material onto the conductive film to form an orientation conductive film with an orientation coating; Step 3: Perform a first heating operation on the orientation coating to partially cure the orientation coating, and then rub the surface of the partially cured orientation coating. Step 4: Coat the polymer-dispersed liquid crystal material between the two oriented conductive films and cure it with ultraviolet light to form an intermediate product in which the first base layer, the first conductive layer, the first oriented coating layer, the polymer-dispersed liquid crystal layer, the second oriented coating layer, the second conductive layer and the second base layer are stacked in sequence. Step 5: Use a laser with fixed focus to etch the first and second conductive layers of the intermediate product to form dividing lines; Step Six: On the first side of the film obtained in Step Five, the second alignment coating, the second conductive layer, and the second substrate layer are cut and scraped off, and the first alignment coating and polymer-dispersed liquid crystal layer on the first conductive layer are wiped clean with an organic solvent to form a first protrusion; On the second side of the intermediate product, the first alignment layer, the first conductive layer, and the first substrate layer are cut off, and the second alignment coating and polymer-dispersed liquid crystal layer on the second conductive layer are wiped clean with an organic solvent to form a second protrusion; Step 7: Perform a second heating operation on the film obtained in Step 6 to completely cure the orientation coating; Step 8: Fabricate the first electrode at the first protrusion and the second electrode at the second protrusion.

2. The laser etching method for preparing a PDLC dimming film with an electrically controllable display pattern according to claim 1, characterized in that... The first orientation layer and the second orientation layer each contain polyimide, and the amount of the fluorescent whitening agent is 0.01~0.05wt% of the polyimide; the fluorescent whitening agent is FP-127, with a fineness ≥300 mesh and a purity ≥99%.

3. The laser etching method for preparing a PDLC dimming film with an electrically controllable display pattern according to claim 2, characterized in that... The first orientation layer and the second orientation layer are respectively formed by doping polyamic acid with fluorescent whitening agent and curing and rubbing.

4. The laser etching method for preparing a PDLC dimming film with an electrically controllable display pattern according to any one of claims 1 to 3, characterized in that... The first alignment layer and the second alignment layer each have a thickness of 3~15μm; the first conductive layer and the second conductive layer are both ITO; the dividing line is an etching line obtained by laser etching; the first substrate layer and the second substrate layer are both PET.

5. The laser etching method for preparing a PDLC dimming film with an electrically controllable display pattern according to claim 1, characterized in that... The organic solvent is ethanol or an ethanol-water solution; the temperature of the first heating operation is higher than the temperature of the second heating operation.

6. The laser etching method for preparing a PDLC dimming film with an electrically controllable display pattern according to claim 5, characterized in that... The temperature of the first heating operation is 150~280℃ and the time is 10~30 minutes; the temperature of the second heating operation is 60~150℃ and the time is 20~30 minutes.

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