Patent Publication Number: US-2023150177-A1

Title: Curved Plastic Panel And Method And Device For Processing The Same

Description:
This application claims the benefit of Taiwan Patent Application Serial No. 110142418 filed Nov. 15, 2021, the subject matter of which is incorporated herein by reference. 
     BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention relates to a curved plastic panel and a processing method and device thereof, especially a processing method and device for firstly providing a hard coating layer and an optical function layer onto a flat plastic substrate and then hot pressing the flat plastic substrate into a curved plastic panel. 
     2. Description of the Prior Art 
     Most of the traditional vehicles use glass as the material for the sunroof, the windshield, and the front panel of the vehicle display. Because glass has disadvantages such as heavy in weight, fragile, and difficulty in shaping, some people have developed transparent plastic plates in recent years to replace traditional glass in order to produce the sunroof, the windshield, and the front panel of the vehicle display. Because the vehicle display needs a curved design that is more in streamline with the interior of the car, in recent years, some manufacturers have begun to think of a vehicle display with a curved surface to replace the traditional flat-panel car display. However, one of the biggest difficulties in the product design of the curved vehicle display is the material of the curved panel covering the front of the curved vehicle display and its manufacturing process. 
     The conventional curved glass panel needs to first process the flat glass plate into curved glass plate by ultra-high temperature thermoforming, and then carry out the surface grinding and polishing of the curved glass plate, and finally carry out optical surface treatments (such as anti-glare or anti-reflection coatings, etc.). However, it is very difficult to control the coating uniformity for optical surface treatments on curved substrates, especially the thickness uniformity of the anti-reflective coating must reach the coating tolerance specification of +/−10 nm, in order to achieve the request of reflectivity of the vehicle front panel &lt;1%. It is quite difficult to achieve this specification in flat panel coating, and it is almost impossible to achieve this on curved panels. 
     Of course, in recent years, various technologies have also been developed to use plastic materials to make vehicle display panels. There are many types of plastics. Among them, engineering plastics composed of polycarbonate (PC for short) have the advantages of high transparency and free dyeing, high strength and elastic coefficient, high impact strength, wide applicable temperature range, low molding shrinkage, good dimensional stability, good weather resistance, tasteless and odorless, harmless to the human body, fulfilling health and safety requirements, easy to shape, and etc. Therefore, it is more suitable for making transparent substrates with curved surfaces or special structures to replace fragile and unshaped glass plates. However, polycarbonate (PC) also has the disadvantages of being non-abrasive and prone to yellowing under ultraviolet light. Thus, in the prior art, a wear-resistant hard coating layer and an optical function layer are added on the outer surface of the polycarbonate (PC) substrate to improve its wear resistance, UV resistance, anti-glare, and anti-reflect properties. 
     However, the conventional technologies still encounter a very difficult problem in manufacturing a plastic panel with a curved surface. As shown in  FIG.  1   , which is a schematic structural diagram of a typical curved plastic panel. Generally speaking, a curved plastic panel suitable for a curved vehicle display includes a plastic substrate, a hard coating layer (HC for short), an optical function layer, and a printing layer in structure. The plastic substrate is usually made of a polycarbonate (PC) layer as the main layer, and at least one polymethyl methacrylate (referred to as PMMA) layer is arranged on the upper and lower surfaces of the PC plate to strengthen the physical properties of the plastic substrate. The hard coating layer is usually formed on the outer surface of the plastic substrate to improve the wear resistance of the plastic panel. The optical function layer is usually formed on the hard coating layer to improve the optical performance of the plastic panel, such as but not limited to: UV resistance, anti-glare, and anti-reflection. The printing layer is usually printed on the inner surface of the plastic substrate to express the functional indicators of the vehicle display. 
     As shown in  FIG.  2   , which is a schematic diagram of a conventional processing method of a plastic panel with a curved surface, which includes the following steps: 
     Step  21 : making a flat plastic substrate (commonly known as a raw board) by plastic extrusion molding. This plastic substrate may be a single-layer PC plate, a PMMA/PC double-layer composite plate, or a PMMA/PC/PMMA three-layer composite plate. 
     Step  22 : hot pressing the flat plastic substrate into a curved plastic substrate by means of hot pressing curvature forming. 
     Step  23 : performing HC surface treatment on the plastic substrate having a curved surface, so as to form a hard coating layer on the upper surface of the plastic substrate having the curved surface. However, due to the difficulty of HC surface treatment on curved plastic substrates, the yield rate is not good. 
     Step  24 : performing optical surface treatment on the plastic substrate having the curved surface, so as to form an optical function layer on the hard coating layer of the plastic substrate having the curved surface. However, due to the difficulty of optical surface treatment on curved plastic substrates, the yield rate is not good. 
     Step  25 : performing a printing process on the plastic substrate having the curved surface, so as to form a printing layer on the lower surface of the plastic substrate having the curved surface. However, because the curved plastic substrate is difficult to print, the yield rate is not good. 
     Step  26 : The plastic substrate having the curved surface is processed by a plane computer numerical control (referred to as CNC) processing machine to cut the plastic substrate having the curved surface into a predetermined contour. However, because it is difficult to perform plane CNC machining on curved plastic substrates, the yield rate is not good. 
     Step  27 : Complete the finished plastic panel with a curved surface. Since the defective rate from Step  23  to Step  26  has a cumulative effect, the yield rate of the final finished product is very low, so there is still room for improvement. 
     As shown in  FIG.  3 A ,  FIG.  3 B  and  FIG.  3 C , which is a schematic diagram of a conventional method of hot pressing a flat plastic substrate into a plastic substrate with a curved surface. The conventional method of hot pressing the flat plastic substrate  221  into a plastic substrate with a curved surface is to first heat the flat plastic substrate  221  to a predetermined temperature in an oven to soften it, and then move the heated and softened flat plastic substrate to a press molding machine. The press molding machine has upper and lower dies  222 ,  223  with fixed shape and invariable curvature. Placing the heated flat plastic substrate  221  between the upper and lower dies  222 ,  223  (as shown in  FIG.  3 A ), and then using the hydraulic cylinder to drive the upper and lower dies  222 ,  223  to overlap and press the plastic substrate  221   a  located therein (as shown in  FIG.  3 B ), the shape of the plastic substrate  221   a  is thereby deformed into a curved plastic substrate  221   a  that fits with the upper and lower dies, and then the curved plastic substrate  221   a  is taken out (as shown in  FIG.  3 C ). This conventional hot pressing technique not only has the problem of uneven temperature of the plastic substrate  221  due to that the heat dissipates much quicker in the peripheral area than the central area and thus the temperature in the peripheral area is lower than the central area during compression, but also has the problem of stress concentration at the bended portion  229  of the curved plastic substrate  221   a  with a large curvature. Therefore, if the flat plastic substrate with the hard coating layer and the optical function layer formed thereon is hot-pressed using this conventional technique, the hard coating layer will be brittle ruptured and the thickness of the optical function layer will be uneven at the bended portion  229  with a large curvature. As a result, the hot-pressed plastic substrate  221   a  with a curved surface is unusable and cannot pass the product test. 
     The traditional curvature surface molding of polymer substrates is to first heat the polymer substrate to a temperature higher than the softening point (Tg; glass transition temperature) of the polymer, and then transfer the heated polymer substrate to a hot pressing mold for curvature surface thermoforming. The temperature change of the substrate caused by the thermal convection of the air at room temperature during the transfer process will affect the curvature and contour accuracy of the hot pressing. The longer the transfer time, the longer the cooling time, the less conducive to controlling the temperature uniformity of the substrate, and the worse the control of the curvature and contour accuracy of the hot pressing. Therefore, reducing the transfer time and cooling time is more conducive to the precision control of curvature and contour. The most ideal process design is that high temperature heating and curvature forming are carried out simultaneously in an automated mold. The key point of the present invention is the sensing elements that can monitor the local temperatures and local curvatures in real time, and feed back to the heating mechanism and the hot pressing mechanism, so as to adjust the plate to reach the optimum forming temperature and target curvature in real time. 
     SUMMARY OF THE INVENTION 
     The primary objective of the invention is to provide a method for processing a curved plastic panel. The method first forms a hard coating layer, an optical function layer, and a printing layer on a flat plastic substrate, and then uses a CNC machine to cut it into a predetermined shape, and then uses a hot pressing and curving device to perform a hot pressing and curving process to the flat plastic substrate in order to make it becoming a curved plastic substrate. The method of the present invention has the advantages of optical function (anti-reflection or anti-glare) and safety and non-breakage in addition to the production of multifunctional polymer material panels for displays with partially or fully curved surfaces. Moreover, since the processing of the hard coating layer, optical function layer, printing layer and CNC cutting are all carried out on the flat plastic substrate, the yield rate is very high, which overcomes various deficiencies of the prior art. 
     The second objective of the invention is to provide a device for processing a curved plastic panel. The device includes a hot pressing and curving device which can simultaneously perform hot pressing process during the heating process to the plastic substrate. In addition, the device has the function of real-time monitoring of local temperatures and real-time monitoring of local curvatures forming state, which can be feedback to local heaters and local pressing mechanisms for real-time adjustments of the temperatures and curvatures of different parts of the plastic substrate being processed. The monitoring of temperatures and curvatures can be divided into multiple stages, and the monitoring and adjustment of heating or curvature shaping can be performed stage by stage. Such that, the production yield rate of hot pressing a flat plastic substrate with a hard coating layer, an optical function layer and a printing layer into a curved plastic panel can be improved, while the thermoforming processing of full-curved or partially-curved plastic panels can also be accomplished. 
     The third objective of the invention is to provide a material composition of the hard coating layer and the optical function layer of the curved plastic panel suitable for the processing method of the present invention. Through the polymer material formulation, coating formulation design and precision coating technology, the ductility properties of polymer surfaces of the plastic substrate having the hard coating layer and the optical function layer can be improved to the level suitable for hot bending, while the original optical and physical properties of the plastic substrate can also be maintained after passing various weather resistance tests. 
     In order to achieve the aforementioned objectives, the present invention provides a processing method of a curved plastic panel. The processing method comprises the steps of: providing a flat plastic substrate; forming a flat hard coating layer on at least one surface of the flat plastic substrate; forming a flat optical functional layer on the hard coating layer of the flat plastic substrate; forming a flat printing layer on at least one surface of the flat plastic substrate; cutting the flat plastic substrate into a predetermined shape by a cutting machine; and using a hot pressing and curving device to perform a hot pressing and curving processing on the flat plastic substrate having the hard coating layer, the optical function layer and the printing layer formed with the predetermined shape, in order to obtain a curved plastic substrate having the hard coating layer, the optical function layer and the printing layer with the predetermined shape. 
     Wherein, the hot pressing and curving device comprises: an upper die with variable curvature, a lower die with variable curvature, a plurality of upper heaters, a plurality of upper temperature sensors, a plurality of lower heaters, and a plurality of lower temperature sensors; the plurality of the upper heaters and the plurality of the upper temperature sensors are distributed in each area of the upper die; the plurality of the lower heaters and the plurality of the lower temperature sensors are distributed in each area of the lower die; the upper die and the lower die are matched correspondingly, and curvatures of the upper die and the lower die can be adjusted at least locally; the hot pressing and curving device is used to process the hot pressing and curving process of the flat plastic substrate in the following steps: 
     adjusting the curvatures of the upper die and the lower die to be flat, and sandwiching the flat plastic substrate between the upper die and the lower die, and using the plurality of the upper heaters and the plurality of the lower heaters to heat the flat plastic substrate to a predetermined temperature, and using the plurality of the upper temperature sensors and the plurality of the lower temperature sensors to sense and monitor the temperature of each area of the flat plastic substrate in order to maintain the temperature of each area of the flat plastic substrate at the predetermined temperature; 
     adjusting the curvatures of the upper die and the lower die to a first curvature, such that the flat plastic substrate sandwiched between the upper die and the lower die is processed by the upper die and the lower die into the curved plastic substrate with the first curvature; in the meantime, the plurality of the upper temperature sensors and the plurality of the lower temperature sensors continue to sense and monitor that the temperature of each area of the curved plastic substrate with the first curvature is maintained at the predetermined temperature; and 
     adjusting the curvatures of the upper die and the lower die to a second curvature, such that the curved plastic substrate sandwiched between the upper die and the lower die is processed by the upper die and the lower die into the curved plastic substrate with the second curvature; in the meantime, the plurality of the upper temperature sensors and the plurality of the lower temperature sensors continue to sense and monitor that the temperature of each area of the curved plastic substrate with the second curvature is maintained at the predetermined temperature; wherein the second curvature is larger than the first curvature. 
     In a preferred embodiment, the hot pressing and curving device further comprises a plurality of cameras for capturing curvature images of the upper die and the lower die, in order to determine whether the curvature of the curved plastic substrate has reached a predetermined curvature. 
     In a preferred embodiment, the upper die at least includes a first upper template, a second upper template and a third upper template; a first upper joint is connected between the first upper template and the second upper template, so that the first upper template can perform a first curvature adjustment movement relative to the second upper template by means of the first upper joint; a second upper joint is connected between the second upper template and the third upper template, so that the third upper template can perform a second curvature adjustment movement relative to the second upper template by means of the second upper joint; 
     the lower die at least includes a first lower template, a second lower template and a third lower template; a first lower joint is connected between the first lower template and the second lower template, so that the first lower template can perform a third curvature adjustment movement relative to the second lower template by means of the first lower joint; a second lower joint is connected between the second lower template and the third lower template, so that the third lower template can perform a fourth curvature adjustment movement relative to the second lower template by means of the second lower joint; 
     wherein, the shape and position of the first upper template are corresponding to the first lower template, the shape and position of the second upper template are corresponding to the second lower template, the shape and position of the third upper template are corresponding to the third lower template. 
     In a preferred embodiment, the plurality of the upper heaters and the plurality of the upper temperature sensors are provided in the first upper template, the second upper template and the third upper template; the plurality of the lower heaters and the plurality of the lower temperature sensors are provided in the first lower template, the second lower template and the third lower template; the first upper joint, the second upper joint, the first lower joint and the second lower joint each includes a linear sliding rail respectively; the curvature between two adjacent said templates is adjusted by a torque driven by the linear sliding rails. 
     In a preferred embodiment, wherein: a material composition of the flat plastic substrate is one of the following: polymethyl methacrylate (PMMA) plate, Polycarbonate (PC) plate, PMMA/PC double-layer composite plate, or PMMA/PC/PMMA three-layer composite plate; a material composition of the hard coating layer comprises at least one of the following: organic-inorganic hybrid ultraviolet (UV) oligomers/monomers, inorganic particle materials, or UV-curable long-chain oligomers/monomers with high elongation properties (elongation ratio&gt;200%); wherein the organic-inorganic hybrid ultraviolet oligomers/monomers include one of the following: UV-curable elastic oligomer with a high glass transition temperature (Tg), or high Tg monomer; wherein the Tg of the UV-curable elastic oligomer is Tg≥120° C.; wherein the Tg of the high Tg monomer is Tg≥240° C.; the optical function layer is composed of at least one of the following: UV-curable oligomers/monomers with high refractive index (RI), inorganic materials with high RI, UV-curable oligomers/monomers with low RI, or inorganic materials with low RI; wherein, the inorganic materials with high RI contain one of the following: titanium dioxide (TiO 2 ) or niobium pentoxide (Nb 2 O 5 ); the inorganic materials with low RI contain one of the following: silicon dioxide (SiO 2 ) or magnesium fluoride (MgF 2 ); the RI value range of the high refractive index UV-curable oligomers/monomers is: RI=1.55˜1.75; the RI value range of the low refractive index UV-curable oligomers/monomers is: RI=1.4˜1.48; the RI value range of the high RI inorganic material is: RI=1.8˜2.5; the RI value range of the low RI inorganic material is: RI=1.2˜1.45. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic structural diagram of a typical curved plastic panel. 
         FIG.  2    is a schematic diagram of a conventional processing method of a plastic panel with a curved surface. 
         FIG.  3 A ,  FIG.  3 B  and  FIG.  3 C  are respectively schematic diagrams of three different steps of a conventional method of hot pressing a flat plastic substrate into a plastic substrate with a curved surface. 
         FIG.  4    which is a schematic diagram of the processing method of the curved plastic panel of the present invention. 
         FIG.  5 A ,  FIG.  5 B ,  FIG.  5 C , and  FIG.  5 D  are schematic diagrams of several stages for hot pressing and curving a flat plastic substrate into a curved plastic substrate according to the present invention. 
         FIG.  5 E  is a schematic top view of the upper die (or lower die) of the hot pressing and curving device of the present invention. 
         FIG.  6    is a schematic flowchart of the real-time monitoring of local temperature and local curvature forming state of the hot pressing and curving device according to the present invention. 
         FIG.  7 A  and  FIG.  7 B  are schematic diagrams of an embodiment of the processing device for a curved plastic panel of the present invention in the states of the door being opened and the door being closed, respectively. 
         FIG.  8 A  and  FIG.  8 B  are schematic diagrams of the upper and lower dies with variable curvature of the hot pressing and curving device in the planar state and the bent state, respectively. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention provides a method for processing a curved plastic panel, which first forms a hard coating layer, an optical function layer, and a printing layer on a flat plastic substrate, and then uses a CNC machine to cut it into a predetermined shape, and then uses a hot pressing and curving device to perform a hot pressing and curving process to the flat plastic substrate in order to make it becoming a curved plastic substrate having the hard coating layer, optical function layer, and printing layer. The method of the present invention has the advantages of optical function (anti-reflection or anti-glare) and safety and non-breakage in addition to the production of multifunctional polymer material panels for displays with partially or fully curved surfaces. Moreover, since the processing of the hard coating layer, optical function layer, printing layer and CNC cutting are all carried out on the flat plastic substrate, the yield rate is very high, which overcomes various deficiencies of the prior art. The hot pressing and curving device of the invention can simultaneously perform hot pressing process during the heating process to the plastic substrate. In addition, the device has the function of real-time monitoring of local temperatures and real-time monitoring of local curvatures forming state, which can be feedback to local heaters and local pressing mechanisms for real-time adjustments of the temperatures and curvatures of different parts of the plastic substrate being processed. The monitoring of temperatures and curvatures can be divided into multiple stages, and the monitoring and adjustment of heating or curvature shaping can be performed stage by stage. Such that, the production yield rate of hot pressing a flat plastic substrate with a hard coating layer, an optical function layer and a printing layer into a curved plastic panel can be improved, while the thermoforming processing of full-curved or partially-curved plastic panels can also be accomplished. The present invention also provides a material composition of the hard coating layer and the optical function layer of the curved plastic panel suitable for the processing method of the present invention. Through the polymer material formulation, coating formulation design and precision coating technology, the ductility properties of polymer surfaces of the plastic substrate having the hard coating layer and the optical function layer can be improved to the level suitable for hot bending, while the original optical and physical properties of the plastic substrate can also be maintained after passing various weather resistance tests. 
     In order to more clearly describe the curved plastic panel and method and device for processing the same proposed by the present invention, the following embodiments will be illustrated in detail with the drawings. 
     The structure of the curved plastic panel described in the present invention is similar to or the same with the typical plastic panel  10  generally suitable for a curved vehicle display as shown in  FIG.  1   , which also comprises: a plastic substrate  11 , a hard coating (HC for short) layer  12 , an optical function layer  13 , and a printing layer  14 . The plastic substrate  11  can be a single-layer PC plate, a single-layer PMMA plate, a co-extrusion formed PMMA/PC double-layer composite plate, a co-extrusion formed PMMA/PC/PMMA three-layer composite plate, or other conventional plastic plate structures. In this embodiment, the plastic substrate  11  is made of a polycarbonate (PC) layer  111  as the main layer, and two polymethyl methacrylate (PMMA) layers  112 ,  113  are respectively arranged on the upper and lower surfaces of the PC layer  111  to strengthen its physical properties. The hard coating layer  12  is usually formed on the outer surface (upper surface) of the plastic substrate  11 , or the hard coating layer  12  is provided on both the outer and inner surfaces (upper and lower surfaces) of the plastic substrate  11  to improve the wear resistance of the plastic panel  10 . In this embodiment, the composition of the hard coating layer  12  includes at least one of the following: organic-inorganic hybrid ultraviolet (UV for short) oligomers/monomers, inorganic particle materials, or UV-curable long-chain oligomers/monomers with high elongation properties (elongation ratio&gt;200%). Wherein, the organic-inorganic hybrid ultraviolet oligomers/monomers include one of the following: UV-curable elastic oligomer with a high glass transition temperature (Tg for short, and its Tg≥120° C.), or high Tg monomer (Tg≥240° C.). The optical function layer  13  is usually formed on the outer surface of the hard coating layer  12  for improving the optical performance of the plastic panel  10 , for example but not limited to: UV resistance, anti-glare, and anti-reflection functions. In this embodiment, the optical function layer  13  is composed of at least one of the following: UV-curable oligomers/monomers with high refractive index (RI for short), inorganic materials with high RI, UV-curable oligomers/monomers with low RI, or inorganic materials with low RI. Wherein, the inorganic materials with high RI contain one of the following: titanium dioxide (TiO 2 ) or niobium pentoxide (Nb 2 O 5 ). The inorganic materials with low RI contain one of the following: silicon dioxide (SiO 2 ) or magnesium fluoride (MgF 2 ). The printing layer  14  is usually printed on the inner surface of the plastic substrate  11  with colored ink for expressing the functional indicators of the vehicle display. Although the structure of the plastic panel  10  of the present invention is similar to that of the prior art, the present invention is particularly novel in the selection of materials for the hard coating layer  12  and the optical function layer  13  to have high Tg value (Tg≥120° C.) and high elongation characteristics (elongation ratio&gt;200%) material formula. By using the high Tg value (Tg≥120° C.) UV-curable elastic oligomer or high Tg monomer (Tg≥240° C.) material formulation in the hard coating layer  12 , a moldable curved plastic panel  10  can be provided with impact resistance, high flexibility, and high temperature stability; it can improve the reliability of high temperature environmental tests or high temperature and high humidity environmental tests. By using the material formulation of UV-curable long-chain oligomers or monomers with high elongation properties (elongation ratio&gt;200%) in the hard coating layer  12 , a moldable curved plastic panel  10  with high elongation properties and high temperature formability can be provided, such that, cracks or uneven thickness of the optical function layer  13  can be avoided during the hot pressing process. 
     In the present invention, the material formulation of the hard coating (HC) layer  12  comprises an organic-inorganic hybrid ultraviolet oligomer. Compared with the traditional high cross-link density HC formula, it has a relatively low cross-link density, and can form a wear-resistant hard coating layer  12  with low shrinkage and good flexibility. Wherein, inorganic materials can contribute to the physical properties of the surface, making the coating to have high hardness and high wear resistance. 
     In addition, the formulation composition of the hard coating layer  12  of the present invention includes a high Tg ultraviolet photo-elastomer oligomer (such as high Tg UV-curable elastic oligomer) and a high Tg monomer, which has better high temperature stability in comparison with traditional high crosslinking density HC formulations. Therefore, it has better thermos-formability during high temperature process, and can bend the UV-cured formable polymer front panel material to a free curvature. The formulation composition of the hard coating layer  12  of the present invention includes UV-curable long-chain oligomers or monomers with high elongation properties (elongation ratio&gt;200%), which has better high extensibility in comparison with traditional high crosslinking density HC formulations. Therefore, it has better thermos-formability during high temperature process, and can bend the UV-cured formable polymer front panel material to a free curvature. The flat plastic panel  10  with the hard coating layer  12  and the optical function layer  13  of the present invention is subjected to flat ink printing and flat surface CNC machining before hot pressing. Then, combining with the hot pressing and curving process of the present invention, it can directly produce curved surface products with optical function after the hot pressing and curving process. For the conventional curved front panel production process, the curved surface hot pressing is performed first, and then the curved surface treatment and curved surface optical processing, curved surface printing, and curved surface CNC cutting processing are performed; due to the difficult processing of curved surfaces, the yield rate of each station is poor, and the reduction in pass-through rate leads to high production costs. In the other hand, the processing method of the present invention has lower processing cost because each processing technology is completed on a plane, and the yield rate and pass-through rate of each station are high. In this embodiment, the RI value range of the high refractive index (RI) UV-curable oligomers/monomers is: RI=1.55˜1.75; the RI value range of the low refractive index (RI) UV-curable oligomers/monomers is: RI=1.4˜1.48; the RI value range of the high RI inorganic material is: RI=1.8˜2.5; the RI value range of the low RI inorganic material is: RI=1.2˜1.45. Anti-reflection is defined as: Reflectance &lt;2%; Anti-glare is defined as: Gloss &lt;100. 
     Please refer to  FIG.  4   , which is a schematic diagram of the processing method of the curved plastic panel of the present invention, which includes the following steps: 
     Step  31 : making a flat plastic substrate (commonly known as a plastic raw board) by plastic extrusion molding; The flat plastic substrate may be a single-layer PC plate, a single-layer PMMA plate, a PMMA/PC double-layer composite plate, or a PMMA/PC/PMMA three-layer composite plate; 
     Step  32 : performing an HC surface treatment on the flat plastic substrate, so as to form a hard coating layer on the upper surface (outer surface) of the flat plastic substrate; because the flat plastic substrate is easy to carry out the HC surface treatment, the yield rate is very high; 
     Step  33 : performing an optical surface treatment on the flat plastic substrate to form an optical function layer on the hard coating layer of the flat plastic substrate; because the flat plastic substrate is easy to carry out the optical surface treatment, the yield rate is very high; 
     Step  34 : performing a printing process on the flat plastic substrate, so as to form a printing layer on the lower surface (inner surface) of the flat plastic substrate; because the flat plastic substrate is easy to carry out the printing process, the yield rate is very high; 
     Step  35 : the flat plastic substrate is cut with a plane computer numerical control (CNC) processing machine (cutting machine) to cut the flat plastic substrate into a flat plastic substrate with a predetermined contour; because the flat plastic substrate is easy to carry out the CNC cutting process, the yield rate is very high; 
     Step  36 : using a hot pressing and curving device to perform a hot pressing and curving process on the flat plastic substrate which has been cut with the predetermined shape and formed with the hard coating layer, the optical function layer and the printing layer, in order to make it a curved plastic substrate having the hard coating layer, the optical function layer and the printing layer and having the predetermined shape; and 
     Step  37 : completing the finished curved plastic panel; since the processing yield rates from steps  32  to  35  are high, the final finished product has high yield rate and precision, and can pass subsequent product testing. 
     As shown in  FIG.  5 A ,  FIG.  5 B ,  FIG.  5 C , and  FIG.  5 D , which are schematic diagrams of several stages for hot pressing and curving a flat plastic substrate into a curved plastic substrate according to the present invention. The processing method of the present invention uses a hot pressing and curving device to perform a hot pressing and curving process on the flat plastic substrate which has been cut with the predetermined shape and formed with the hard coating layer, the optical function layer and the printing layer, in order to make it a curved plastic substrate  41  having the hard coating layer, the optical function layer and the printing layer and having the predetermined shape. The hot pressing and curving device comprises: an upper die  42  with a variable curvature, a lower die  43  with a variable curvature, a plurality of upper heaters  421 , a plurality of upper temperature sensors  422 , and a plurality of lower heaters  431 , and a plurality of lower temperature sensors  432 . Please refer to  FIG.  5 E , which is a schematic top view of the upper die (or lower die) of the hot pressing and curving device of the present invention. In this embodiment, a plurality of the upper heaters  421  and a plurality of the upper temperature sensors  422  are evenly and staggeredly distributed in each area of the upper die  42  in an array manner; in addition, a plurality of the lower heaters  431  and a plurality of the lower temperature sensors  432  are also evenly and staggeredly distributed in each area of the lower die  43  in an array manner. The outer contours and structures of the upper die  42  and the lower die  43  are correspondingly matched and their curvatures can be adjusted at least partially. In this embodiment, the hot pressing and curving device performs the hot pressing and curving process on the flat plastic substrate  41  by the following steps: 
     As shown in  FIG.  5 A , first, the curvature of the upper die  42  and the lower die  43  is adjusted to a plane (curvature=0); and then, the flat plastic substrate  41  is sandwiched between the upper die  42  and the lower die  43 ; and then, the temperature of the flat plastic substrate  41  is heated to a predetermined temperature by a plurality of the upper heaters  421  and a plurality of the lower heaters  431 , and a plurality of the upper temperature sensors  422  and a plurality of the lower temperature sensors  432  are used to sense, monitor or feedback to control the temperature of each area of the flat plastic substrate  41  is maintained at the predetermined temperature. 
     As shown in  FIG.  5 B , then, the curvatures of the upper die  42  and the lower die  43  are adjusted to a first curvature (relatively small curvature), such that the flat plastic substrate  41  sandwiched between the upper die  42  and the lower die  43  becomes a curved plastic substrate  41  with the first curvature due to hot pressing by the upper die  42  and the lower die  43 . In the meantime, the plurality of upper temperature sensors  422  and the plurality of lower temperature sensors  432  continue to sense, monitor and feedback to control that the temperature of each area of the curved plastic substrate  41  with the first curvature is consistently maintained at the predetermined temperature. 
     And then, as shown in  FIG.  5 C , the curvatures of the upper die  42  and the lower die  43  are adjusted to a second curvature (relatively larger curvature), such that the curved plastic substrate  41  sandwiched between the upper die  42  and the lower die  43  becomes a curved plastic substrate  41  with the second curvature due to hot pressing by the upper die  42  and the lower die  43 . In the meantime, the plurality of upper temperature sensors  422  and the plurality of lower temperature sensors  432  still continue to sense, monitor and feedback to control that the temperature of each area of the curved plastic substrate  41  with the second curvature is consistently maintained at the predetermined temperature. Wherein, the second curvature is larger than the first curvature. 
     As shown in  FIG.  5 D , when the curvature of the curved plastic substrate  41  (i.e., the curvature of the upper die  42  and the lower die  43 ) reaches a predetermined curvature, the upper and lower dies  42 ,  43  can be opened in order to take out the curved plastic substrate  41  with the predetermined curvature. Since the hot pressing and curving device of the present invention is provided with a plurality of heaters  421 ,  431  and temperature sensors  422 ,  432  on the upper and lower dies  42 ,  43  respectively to perform heating and temperature control, each heater  421 ,  431  and the temperature sensors  422  and  432  can operate independently to control the temperature, so the temperature of each area of the plastic substrate  41  is stable and uniform during the hot pressing and curving process. In addition, the hot pressing and curving device can simultaneously perform hot pressing during the heating process, and has the functions of real-time monitoring of local temperature and local curvature forming state and then feedback to the local heating and curving mechanisms for local adjustments. The monitoring of temperatures and curvatures can be divided into multiple stages, and the monitoring and adjustment of heating and curvature shaping can be performed stage by stage; such that, the stress concentration or cracking of the hard coating layer can be avoided at the bended portion  49  of the curved plastic substrate  41 , and the production yield rate can be improved. Through the polymer material formulation, coating formulation design and precision coating technology, the ductility properties of polymer surfaces (especially the hard coating layer) of the plastic substrate can be improved to the level suitable for hot bending, while the original optical and physical properties of the hot-pressed and curved plastic substrate can also be maintained after passing various weather resistance tests. 
     Please refer to  FIG.  6   , which is a schematic flowchart of the real-time monitoring of local temperature and local curvature forming state of the hot pressing and curving device according to the present invention. As shown in  FIG.  6   , and referencing  FIG.  5 A  to  FIG.  5 D ; during the hot pressing and curving process, first, in the first step (the 1 st  Step)  361 , as shown in  FIG.  5 A , the upper and lower dies  42 ,  43  are still in a low temperature and flat (curvature=0) state; at this time, each part of the plastic substrate is locally heated by a plurality of heaters  421  and  431  (step  3611 ), and each part of the plastic substrate is sensed by a plurality of temperature sensors  422  and  432  for local temperature sensing. If a certain temperature sensor  422 ,  432  senses that the temperature of any part (area) does not reach the predetermined temperature, the signal of such sensor will be feedback to a control unit in order to control the corresponding heaters  421 ,  431  to heat that part (area) (step  3612 ) until all parts of the plastic substrate are heated to reach the predetermined temperature. At the same time, the hot pressing and curving device also uses the curvature sensors to monitor the curvature of each local position of the upper and lower dies  42  and  43  in real time (step  3613 ). If it is detected that the curvature of any part (area) does not reach the first curvature, the signal of such detection will be feedback to the control unit in order to control the corresponding upper and lower dies  42  and  43  to perform local bending of that part (area) (step  3614 ) until all parts of the plastic substrate are bent and curved to reach the first curvature. Then, it will enter the second step (the 2 nd  Step)  362 ; at this time, as shown in  FIG.  5 B , the upper and lower dies  42 ,  43  have been maintained at a predetermined temperature and have a relatively small first curvature. At this time, the plurality of heaters  421  and  431  continue to locally heat each part of the plastic substrate (step  3621 ), and the plurality of temperature sensors  422  and  432  continue to locally sense the temperature of each part of the plastic substrate. If a certain temperature sensor  422 ,  432  senses that the temperature of any part (area) does not reach the predetermined temperature, the signal of such sensor will be feedback to the control unit in order to control the corresponding heaters  421 ,  431  to heat that part (area) (step  3622 ) until all parts of the plastic substrate are heated to maintain at the predetermined temperature. At the same time, the hot pressing and curving device also keep using the curvature sensors to monitor the curvature of each local position of the upper and lower dies  42  and  43  in real time (step  3623 ). If it is detected that the curvature of any part (area) does not reach the second curvature, the signal of such detection will be feedback to the control unit in order to control the corresponding upper and lower dies  42  and  43  to perform local bending of that part (area) (step  3624 ) until all parts of the plastic substrate are bent and curved to reach the second curvature. Wherein, the second curvature is larger than the first curvature. Then, it will enter the third step (the 3 rd  Step)  363 ; at this time, as shown in  FIG.  5 C , the upper and lower dies  42 ,  43  have been maintained at a predetermined temperature and have a relatively larger second curvature. At this time, the plurality of heaters  421  and  431  continue to locally heat each part of the plastic substrate (step  3631 ), and the plurality of temperature sensors  422  and  432  continue to locally sense the temperature of each part of the plastic substrate. If a certain temperature sensor  422 ,  432  senses that the temperature of any part (area) does not reach the predetermined temperature, the signal of such sensor will be feedback to the control unit in order to control the corresponding heaters  421 ,  431  to heat that part (area) (step  3632 ) until all parts of the plastic substrate are heated to maintain at the predetermined temperature. At the same time, the hot pressing and curving device also keep using the curvature sensors to monitor the curvature of each local position of the upper and lower dies  42  and  43  in real time (step  3633 ). If it is detected that the curvature of any part (area) does not reach the predetermined curvature, the signal of such detection will be feedback to the control unit in order to control the corresponding upper and lower dies  42  and  43  to perform local bending of that part (area) (step  3634 ) until all parts of the plastic substrate are bent and curved to reach the predetermined curvature. Wherein, the predetermined curvature is larger than the second curvature. Finally, a finished curved plastic panel with the predetermined curvature can be obtained (the 4 th  Step  364 ). 
     Please refer to  FIG.  7 A  and  FIG.  7 B , which are schematic diagrams of an embodiment of the processing device for a curved plastic panel of the present invention in the states of the door being opened and the door being closed, respectively. In this embodiment, the processing device of the curved plastic panel of the present invention includes the hot pressing and curving device. In the hot pressing and curving device  50  shown in  FIG.  7 A  and  FIG.  7 B , in addition to the aforementioned upper die  42  with variable curvature, lower die  43  with variable curvature, a plurality of upper heaters  421 , a plurality of upper temperature sensors  422 , a plurality of lower heaters  431 , and a plurality of lower temperature sensors  432 , the hot pressing and curving device  50  further comprises the following components: a machine body  51 , a door  52  that can be opened and closed, a plurality of hydraulic devices  53  and  54 , a plurality of cameras  55 , and a control unit  60 . The control unit  60  further comprises: a heating module  61 , a detecting module (including a temperature sensing module  62  and an image capturing module  64 ), a driving device  63 , a database  65 , an analysis module  66 , a control module  67 , a power module  68  and a user interface  69 . 
     In this embodiment, the door  52  is installed on the machine body  51 . When the door  52  is opened (as shown in  FIG.  7 A ), the flat plastic substrate  41  to be hot-pressed can be placed between the upper and lower die  42  and  43  in the machine body  51 , or, the processed curved plastic substrate  41  can be taken out of the machine body  51  from between the upper and lower dies  42  and  43 . When the door  52  is closed (as shown in  FIG.  7 B ), the hot pressing and curving processing of the plastic substrate  41  can be performed. The upper and lower dies  42 ,  43  are respectively combined with a plurality of hydraulic devices  53 ,  54  by mold locking mechanisms  531 ,  541 . The hydraulic devices  53  and  54  are actuated by the driving device  63  to provide pushing and pulling forces to the upper and lower dies  42  and  43 , which are used to drive the upper and lower dies to exert pressure or locally bend (change the curvature), in order to perform the hot pressing and curving process on the plastic substrate  41  sandwiched between the upper and lower dies  42  and  43 . 
     The plurality of cameras  55  constitute the curvature sensors, which can capture (photograph) the curvature (appearance) images of the upper and lower dies  42  and  43  in real time during the hot pressing and curving process. By analyzing the curvature (appearance) images of the upper and lower dies  42  and  43 , the curving state of the plastic substrate  41  sandwiched between the upper and lower dies  42  and  43  at that time, that is, the curvature state, can be obtained; and then, it can be determined immediately that whether the curvature of the curved plastic substrate  41  has reached the predetermined curvature or not. 
     The heating module  61  is electrically connected to the upper heaters  421  and lower heaters  431  for controlling the heating operation of the upper heaters  421  and the lower heaters  431 . The detecting module further includes a temperature sensing module  62  and an image capturing module  64 . The temperature sensing module  62  is electrically connected to a plurality of the upper temperature sensors  422  and a plurality of the lower temperature sensors  432  for obtaining sensed temperature information from the upper temperature sensors  422  and the lower temperature sensors  432 . The image capturing module  64  is electrically connected to the plurality of cameras  55  for capturing/receiving the curvature (appearance) images of the upper die  42  and the lower die  43  captured by the plurality of cameras  55 . The database  65  stores the computer software and related parameters required to control the operation of the hot pressing and curving device  50 , and also includes the data of the predetermined temperature, the first curvature, the second curvature and the predetermined curvature. 
     The analysis module  66  can receive the temperature information and the curvature images from the detecting module, and can retrieve the data of the predetermined temperature and the first, second and predetermined curvatures from the database  65 . The analysis module  66  can compare the temperature information with the predetermined temperature; when the temperature of the temperature information is lower than the predetermined temperature, the analysis module  66  generates a heating signal to the heating module  61  to actuate the heating module  61  to control a plurality of the upper heaters  421  and a plurality of the lower heaters  431  to heat the plastic substrate  41 . The heating operations described here may be global or localized heating. In other words, according to the heating signal from the analysis module  66 , the heating module  61  can not only control all the heaters to heat the plastic substrate  41  comprehensively, on the other hand, the heating module  61  can of course only controls some of the heaters to locally heat the plastic substrate  41  according to the heating signal from the analysis module  66 , such feature is uniquely created by the present invention and cannot be achieved by conventional technologies. Besides, the analysis module  66  can also compare the curvature images with the predetermined curvature; when the curvature of the curvature image is smaller than the predetermined curvature, the analysis module  66  generates a curvature increase signal to the driving device  63 , so that the driving device  63  drives the hydraulic devices  53  and  54  to drive the upper die  42  and the lower die  43  to perform a hot pressing operation that can increase the bending curvature globally or locally. The user interface  69  can allow the user to operate the hot pressing and curving device  50  and also allow the user to input or set-up various information such as the predetermined temperature and the predetermined curvature in the database  65 . In this embodiment, the user interface  69  includes a transmission port for connecting with an external computer device. The user can transmit the predetermined temperature, the predetermined curvature and other processing parameters through the user interface  69  and store them in the database  65  by operating the computer device. In another embodiment, the user interface  69  may also include a touch screen and/or a keyboard. The user can set-up the predetermined temperature, the predetermined curvature and other processing parameters in the database  65  by operating the touch screen and/or the keyboard. The control module  67  includes a micro-controller unit (MCU) or a central processing unit (CPU), which is electrically connected to and controls the operations of the driving device  63 , the heating module  61 , the detecting module, the database  65 , the analysis module  66  and the user interface  69 . The power module  68  is connected to the control module  67  for providing power to the control unit  60 . 
     Please refer to  FIG.  8 A  and  FIG.  8 B , which are schematic diagrams of the upper and lower dies with variable curvature of the hot pressing and curving device in the planar state and the bent state, respectively. In the present invention, both the upper and lower die  42  and  43  of the hot pressing and curving device  50  have variable curvatures. In addition, the specific inner structure of the upper and lower dies  42 ,  43  need to be designed according to the curved figure of the curved plastic panel to be produced; and, the purpose of bending the upper and lower dies  42 ,  43  is achieved by the relative torque driven by the linear sliding rails. In one embodiment, the upper die  42  at least includes a first upper template on the left, a second upper template in the middle, and a third upper template on the right. A first upper joint  420   a  is connected between the first upper template and the second upper template, so that the first upper template can perform a curvature adjustment movement relative to the second upper template by means of the first upper joint  420   a . A second upper joint  420   b  is connected between the second upper template and the third upper template, so that the third upper template can perform a curvature adjustment movement relative to the second upper template by means of the second upper joint  420   b . Similarly, the lower die  43  at least includes a first lower template on the left, a second lower template in the middle, and a third lower template on the right. A first lower joint  430   a  is connected between the first lower template and the second lower template, so that the first lower template can perform a curvature adjustment movement relative to the second lower template by means of the first lower joint  430   a . A second lower joint  430   b  is connected between the second lower template and the third lower template, so that the third lower template can perform a curvature adjustment movement relative to the second lower template by means of the second lower joint  430   b . Wherein, the shape and position of the first upper template are corresponding to the first lower template, the shape and position of the second upper template are corresponding to the second lower template, the shape and position of the third upper template are corresponding to the third lower template. A plurality of the upper heaters  421  and a plurality of the upper temperature sensors  422  are provided in the first upper template, the second upper template and the third upper template. A plurality of the lower heaters  431  and a plurality of the lower temperature sensors  432  are provided in the first lower template, the second lower template and the third lower template. The first upper joint  420   a , the second upper joint  420   b , the first lower joint  430   a  and the second lower joint  430   b  each includes a linear sliding rail  4201 ,  4301  respectively. The bending curvature between the two adjacent templates is adjusted by the torque driven by the linear sliding rails  4201  and  4301 . 
     This technology uses PMMA/PC/PMMA or PMMA/PC composite material as the base material, and uses the wet coating process of the extensible coating formulation to produce the extensible composite material front panel. The hot pressing and curving process is performed only after all surface treatments are completed, and moreover, all surface treatments will not endure any appearance and functional abnormalities at this stage of the hot pressing and curving process. The key to the breakthrough of this process lies in the matching of extensible coating formulations. Extensible coating formulations include: extensible high hardness coating, extensible high refractive index coating, and extensible low refractive index coating. The formula of extensible coating can change the process that the glass used in the old conventional technology must be hot-pressed to form the curved surface first and then subjected to optical surface treatments next, which greatly reduces the defect rate of the curved surface coating process. The surface hardness of the front plastic panel with the extensible composite material after hot pressing and curving process can be increased to more than 4H (4H˜9H); the chemical wear resistance test can pass the vehicle standard level; UV yellowing resistance test (1000 hours) can maintain the specification of ΔE&lt;3. 
     The Applicant tested a variety of plastic substrates with different structures with different hard coating and optical function layers composed of different materials. The following Table 1 shows the structural information of each sample tested. For example, the substrate of Sample 6 in Table 1 selects A3/A4 structure in column A, that is, either “PMMA/PC double-layer plate structure” or “PMMA/PC/PMMA three-layer plate structure” is selected. In column B for Sample 6, whether there is “Inorganic hybrid composition” (organic-inorganic hybrid oligomer/monomer) added to the hard coating layer is to choose B2, that is, Sample 6 is added “with” Inorganic hybrid composition. In column C for Sample 6, whether there is added “High Tg composition” (high glass transition temperature oligomer/monomer) in the hard coating layer is to choose C2, that is, Sample 6 is added “with” High Tg composition. In column D for Sample 6, whether there is “High Elongation Composition” (high elongation oligomer/monomer) added to the hard coating layer is to choose D2, that is, Sample 6 is added “with” High Elongation Composition (oligomer/monomer). In column E for Sample 6, whether to add “Optical Function Composition” (optical function component) to its optical function layer is to choose E2, that is, Sample 6 is added “with” Optical Function Composition. In column F for Sample 6, whether the “new mold and hot pressing and curving process” of the present invention being applied is to select F2, that is, Sample 6 is applied “with” the new mold and hot pressing and curving process of the present invention. The structure of other samples (Samples 0˜5, and 7˜9) can be learned in the same way, so it is not repeated here. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 the structural information of each sample tested 
               
            
           
           
               
               
            
               
                   
                 Component 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 A: Polymer 
                   
                   
                   
                   
                   
                   
               
               
                   
                 material 
                   
                   
                   
                   
                 F: new mold 
               
               
                   
                 selection 
                   
                   
                   
                   
                 and hot 
               
               
                   
                 A1: PC 
                 B: Inorganic 
                   
                 D: High 
                 E: Optical 
                 pressing and 
               
               
                   
                 A2: PMMA 
                 hybrid 
                 C: High Tg 
                 Elongation 
                 Function 
                 curving 
               
               
                   
                 A3: PMMA/PC 
                 composition 
                 Composition 
                 Composition 
                 Composition 
                 process 
               
               
                 Sample 
                 A4: PMMA/PC/ 
                 B1: Without 
                 C1: Without 
                 D1: Without 
                 E1: Without 
                 F1: Without 
               
               
                 No. 
                 PMMA 
                 B2: With 
                 C2: With 
                 D2: With 
                 E2: With 
                 F2: With 
                 Remark 
               
               
                   
               
               
                 Sample 0 
                 A1~A4 
                 — 
                 — 
                 — 
                 — 
                 F1 
                 Poor molding, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 Surface scratches 
               
               
                   
                   
                   
                   
                   
                   
                   
                 after molding 
               
               
                 Sample 1 
                 A1~A4 
                 — 
                 — 
                 — 
                 — 
                 F2 
                 Molding OK, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 Surface scratches 
               
               
                   
                   
                   
                   
                   
                   
                   
                 after molding 
               
               
                 Sample 2 
                 A3/A4 
                 B2 
                 C2 
                 D1 
                 E2 
                 F2 
                 With optical 
               
               
                   
                   
                   
                   
                   
                   
                   
                 function, Easy to 
               
               
                   
                   
                   
                   
                   
                   
                   
                 crack at bent area 
               
               
                 Sample 3 
                 A3/A4 
                 B2 
                 C1 
                 D2 
                 E2 
                 F2 
                 With optical 
               
               
                   
                   
                   
                   
                   
                   
                   
                 function, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 Appearance 
               
               
                   
                   
                   
                   
                   
                   
                   
                 defects during 
               
               
                   
                   
                   
                   
                   
                   
                   
                 heating 
               
               
                 Sample 4 
                 A3/A4 
                 B1 
                 C2 
                 D2 
                 E2 
                 F2 
                 With optical 
               
               
                   
                   
                   
                   
                   
                   
                   
                 function, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 Insufficient 
               
               
                   
                   
                   
                   
                   
                   
                   
                 hardness and 
               
               
                   
                   
                   
                   
                   
                   
                   
                 poor scratch 
               
               
                   
                   
                   
                   
                   
                   
                   
                 resistance 
               
               
                 Sample 5 
                 A3/A4 
                 B2 
                 C2 
                 D2 
                 E1 
                 F2 
                 Hardness, heat 
               
               
                   
                   
                   
                   
                   
                   
                   
                 resistance, and 
               
               
                   
                   
                   
                   
                   
                   
                   
                 molding are OK, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 Without optical 
               
               
                   
                   
                   
                   
                   
                   
                   
                 function 
               
               
                 Sample 6 
                 A3/A4 
                 B2 
                 C2 
                 D2 
                 E2 
                 F2 
                 Hardness, heat 
               
               
                   
                   
                   
                   
                   
                   
                   
                 resistance, and 
               
               
                   
                   
                   
                   
                   
                   
                   
                 molding are OK, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 With optical 
               
               
                   
                   
                   
                   
                   
                   
                   
                 function 
               
               
                 Sample 7 
                 A1 
                 B2 
                 C2 
                 D2 
                 E2 
                 F2 
                 Heat resistance, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 and molding OK, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 Poor hardness 
               
               
                   
                   
                   
                   
                   
                   
                   
                 and yellowing 
               
               
                   
                   
                   
                   
                   
                   
                   
                 resistance 
               
               
                 Sample 8 
                 A2 
                 B2 
                 C2 
                 D2 
                 E2 
                 F2 
                 Hardness, and 
               
               
                   
                   
                   
                   
                   
                   
                   
                 molding OK, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 Poor heat and 
               
               
                   
                   
                   
                   
                   
                   
                   
                 impact resistance 
               
               
                 Sample 9 
                 A3/A4 
                 B2 
                 C2 
                 D2 
                 E2 
                 F1 
                 Poor molding, 
               
               
                   
                   
                   
                   
                   
                   
                   
                 Poor yield rate 
               
               
                   
               
            
           
         
       
     
     It can be seen from Table 1 that, the curved plastic panel of Sample 6 has OK hardness, heat resistance, and molding, and has optical functions, which is a relatively optimal curved plastic panel sample. Relatively, other samples 0˜5, 8, and 9 are more or less including some deficiencies. 
     In this embodiment, the material compositions described in each column A to E can be selected from currently commercially available commodities. For example, the “Inorganic hybrid composition” described in the column B can be selected from Allenx EBECRYL 8311 or other products of the same type or brand. The “High Tg composition” described in column C can be selected from Allenx EBECRYL 4859 or similar products of other models or brands. The “High Elongation Composition” described in column D can be selected from Allenx EBECRYL 8804 or similar products of other models or brands. The “Optical Function Composition” described in column E can be selected from Nippon Shokubai ZIRCOSTAR series products or products of the same nature of other models or brands. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 The test results of each sample of the curved plastic panel 
               
            
           
           
               
               
            
               
                   
                 Tested item 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 QUV 
                   
                 85° C., 
               
               
                   
                   
                   
                 Ball 
                   
                 High 
                   
                   
                   
                   
                 1000 hrs 
                 105° C. 
                 85% RH 
               
               
                   
                   
                   
                 impact 
                   
                 temper- 
                   
                   
                   
                   
                 Environ- 
                 1000 hrs 
                 1000 hrs 
               
               
                   
                   
                 Surface 
                 resis- 
                 UVB 
                 ature 
                 HC 
                   
                 External 
                 Yield 
                 mental 
                 Environ- 
                 Environ- 
               
               
                   
                 Pencil 
                 wear 
                 tance 
                 Weather 
                 heat 
                 stretch 
                   
                 curvature 
                 rate of 
                 test 
                 mental 
                 mental 
               
               
                 Sample 
                 hardness/ 
                 resis- 
                 (cm)/ 
                 resis- 
                 resis- 
                 form- 
                 Optical 
                 form- 
                 mass 
                 results 
                 test 
                 test 
               
               
                 No. 
                 750 g 
                 tance 
                 375 g 
                 tance 
                 tance 
                 ability 
                 properties 
                 ability 
                 production 
                 (ΔE) 
                 results 
                 results 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 Sample 0 
                 ≤H 
                 X 
                 — 
                 — 
                 X 
                 — 
                 — 
                 NG 
                 &lt;10%  
                 &gt;3 
                 X 
                 X 
               
               
                 Sample 1 
                 ≤H 
                 X 
                 — 
                 — 
                 X 
                 — 
                 — 
                 OK 
                 &lt;10%  
                 &gt;3 
                 X 
                 X 
               
               
                 Sample 2 
                 ≥3H 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 X 
                 ⊚ 
                 OK 
                 40% 
                 &lt;2 
                 ⊚ 
                 ⊚ 
               
               
                 Sample 3 
                 ≥3H 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 X 
                 ⊚ 
                 ⊚ 
                 OK 
                 60% 
                 &lt;2 
                 ⊚ 
                 Δ 
               
               
                 Sample 4 
                 H 
                 Δ 
                 ⊚ 
                 Δ 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 OK 
                 80% 
                 &lt;2 
                 ⊚ 
                 Δ 
               
               
                 Sample 5 
                 ≥3H 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 — 
                 OK 
                 &gt;90%  
                 &lt;2 
                 ⊚ 
                 ⊚ 
               
               
                 Sample 6 
                 ≥3H 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 OK 
                 &gt;90%  
                 &lt;2 
                 ⊚ 
                 ⊚ 
               
               
                 Sample 7 
                 HB 
                 ◯ 
                 ⊚ 
                 X 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 OK 
                 20% 
                 &gt;10 
                 ⊚ 
                 ⊚ 
               
               
                 Sample 8 
                 H 
                 ⊚ 
                 X 
                 ⊚ 
                 ◯ 
                 ⊚ 
                 ⊚ 
                 OK 
                 20% 
                 &lt;1 
                 X 
                 X 
               
               
                 Sample 9 
                 ≥3H 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 ⊚ 
                 NG 
                 30% 
                 &lt;2 
                 ⊚ 
                 ⊚ 
               
               
                   
               
               
                 ⊚: Excellent 
               
               
                 ◯: Good 
               
               
                 Δ: Normal 
               
               
                 X: Fail 
               
               
                 NG: Not Good 
               
            
           
         
       
     
     It can be seen from the testing results of the samples of curved plastic panel listed in the Table 2 that, because Sample 6 uses PC/PMMA or PMMA/PC/PMMA composite plate as the plastic substrate, and is provided with the hard coating layer containing organic-inorganic hybrid oligomer/monomer with high Tg and high elongation properties and the optical function layer, and is processed by using the new mold and hot pressing and curving process of the present invention; that is, Sample 6 is similar to the embodiment shown in  FIG.  4   ,  FIGS.  5 A- 5 C  and  FIG.  6   ; therefore, Sample 6 can obtain excellent or pretty good performances in all tests. In contrast, the other samples (Samples 0˜5, 7 and 8) performed more or less poorly in some of the test items. It can be proved that, compared with the prior art, the curved plastic panel produced by the processing method of the present invention can indeed obtain better test results. 
     While the present invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be without departing from the spirit and scope of the present invention.