Patent Publication Number: US-8973261-B2

Title: Manufacturing method of object having conductive line

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a manufacturing method of an object having a conductive line, and more particularly to a manufacturing method of forming a conductive line in an object by an in-mold roller (IMR) process and a structure of the object. 
     2. Related Art 
     With the rapid development of the electronics industry, especially the development of electronic products in the field of wireless communications has shown a trend of diversified designs. Light, thin, and mini electronic products become a mainstream in the market, for example, electronic products having wireless antennas such as a notebook computer, a personal digital assistant (PDA), a mobile phone, a tablet computer, and a handheld game console. 
     In order to make the above electronic devices light, currently, flexible printed circuit (FPC) boards are mostly used to replace conventional rigid printed circuit boards. In addition, in order to enable an electronic device having a wireless communication function to transmit data, the electronic device has to be equipped with an antenna capable of receiving and transmitting electromagnetic signals, and a signal processing circuit electrically coupled to the antenna, so as to realize the wireless communication function successfully. 
     Taking a notebook computer as an example, for an antenna, in addition to an original wireless communication function, the beauty appearance of the notebook computer further has to be considered, so that various designs of the antenna (for example, an inverted F-shaped antenna and a sheet-shaped antenna) shall be developed, so as to hide the antenna inside the notebook computer. 
     In order to further save space inside the notebook computer, and enable more electronic components to be installed inside the computer, a design of disposing the antenna on an inner side surface of a casing of an electronic device is developed. 
     However, the above conventional antenna is made of metal foil (for example, a copper alloy foil), and the conventional antenna has to be adhered at a preset position on an inner side surface of a casing accurately. Since a structure and a manufacturing process of the conventional antenna are too complicated, and the thickness and an overall size of the antenna are too large, the structure of an electronic device cannot be simplified or downsized, and at the same time manufacturing cost is increased. 
     In addition, in the prior art, an in-mold foil/film (IMF) process is already used as a technique to form a circuit layout on a casing of an electronic device. For films used in the IMF process, an ink layer is between a thin casing and a plastic. During a plastic injection molding process, an IMF film is placed in a mold, and a plastic is injected in the mold to form a plastic casing together with the film. 
     A following problem exists in the prior art. Three-dimensional line layout can be provided on an FPC, circuit layout on the FPC uses metal materials such as copper alloy, or an IMF is used to form a circuit, which brings difficulties during practical line layout, and makes the design of the circuit layout of the FPC too complicated. 
     In addition, for the IMF, the film is embedded into the casing, the process has complicated procedures, and a yield rate is not easy to be controlled, thus result in overhigh manufacturing cost and incapability of increasing production. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is a manufacturing method of an object having a conductive line and a structure thereof, so as to solve the problem that a casing having a complicated structure is unable to be manufactured in a conventional process of disposing an antenna at a casing of an electronic device, and procedures of an IMF process are too complicated thus causing difficulties to the control of a yield rate. 
     The present invention provides a manufacturing method of an object having a conductive line, and the method comprises the following steps. A hardening layer and a conductive line layer are formed on a surface of a carrier sheet in sequence. The carrier sheet, the conductive line layer, and the hardening layer form an IMR material. The conductive line layer of the IMR material is formed on a non-conductive substrate by an IMR process. The carrier sheet is then separated to expose the hardening layer. A connecting piece is formed on the hardening layer. The connecting piece runs through the hardening layer by a connection process, and the connecting piece is electrically connected to the conductive line layer. 
     The present invention provides a structure of an object having a conductive line, and the structure comprises a non-conductive substrate, a conductive line layer, a hardening layer, and a connecting piece. The conductive line layer is disposed on the non-conductive substrate. The conductive line layer is disposed on the non-conductive substrate through an IMR material by an IMR process. The hardening layer is disposed on the conductive line layer. The hardening layer is disposed on the conductive line layer through the IMR material by the IMR process. The connecting piece is disposed on the hardening layer. The connecting piece runs through the hardening layer, and is electrically connected to the conductive line layer. 
     Beneficial effects of the present invention are as follows. A conductive line layer is integrally formed in a structure of an object by an IMR process so that the object having a complicated shape and structure can be manufactured. In addition, procedures of the process of the present invention are greatly simplified, so that objects having a conductive line layer can be manufactured in large quantities continuously, and a manufacturing yield rate is increased dramatically at the same time, thus decreasing the manufacturing cost. 
     These and other aspects of the present invention will become apparent from the following description of the preferred embodiment taken in conjunction with the following drawings, although variations and modifications therein may be affected without departing from the spirit and scope of the novel concepts of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate one or more embodiments of the invention and, together with the written description, serve to explain the principles of the invention. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment, and wherein: 
         FIG. 1  is a flow chart according to a first embodiment of the present invention; 
         FIGS. 2A to 2F  are schematic views of steps according to the first embodiment of the present invention; 
         FIGS. 3A to 3D  are schematic views of steps of another forming method according to the first embodiment of the present invention; 
         FIG. 4  is a plane side view according to the first embodiment of the present invention; 
         FIG. 5  is a flow chart according to a second embodiment of the present invention; 
         FIG. 6  is schematic sectional view according to the second embodiment of the present invention; and 
         FIG. 7  is a plane side view according to the second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a flow chart according to a first embodiment of the present invention, and  FIGS. 2A to 2D  are schematic views of steps according to the first embodiment of the present invention 
     As shown in  FIG. 1  and  FIGS. 2A to 2F , a manufacturing method of an object having a conductive line  200  according to the first embodiment of the present invention comprises the following steps. A film-shaped carrier sheet  210  is provided first. The carrier sheet is made of Polyethylene Terephthalate (PET), Polycarbonate (PC), Cellulose Triacetate (TAC), Acrylic (PMMA) or Cyclic Olefin Polymers (COC), but the present invention is not limited thereto. 
     Referring to  FIGS. 1 and 2A , a hardening layer  230  and a conductive line layer  220  are formed on a surface of the carrier sheet  210  in sequence (Step  100 ). The carrier sheet  210 , the conductive line layer  220 , and the hardening layer  230  form an IMR material. In the present invention, the conductive line layer comprises gold, silver, copper, conductive carbon powder, silver-carbon powder, or mixed powder of carbon and graphite, so as to achieve electric conductivity. 
     The conductive line layer  220  provided by the present invention may be used as an antenna on a casing of an electronic device, or a circuit layout on a casing of an electronic device, but the present invention is not limited thereto. In addition, the conductive line layer  220  of the present invention may also be used as a decorative pattern on a casing of an electronic device, thus achieving a beautiful appearance. 
     In this embodiment, the step of forming the IMR material further comprises a step of forming an adhesion layer  250  on the conductive line layer  220  (Step  101 ), and a step of forming a release layer  260  between the carrier sheet  210  and the hardening layer  230  (Step  102 ), so as to form the IMR material. 
     It should be noted that, in this embodiment, the conductive line layer  220  is formed on the carrier sheet  210  by adhesion. The conductive line layer  220  may be formed on the carrier sheet  210  by hot stamping, or the conductive line layer  220  may be formed on the carrier sheet  210  by evaporation, or the conductive line layer  220  may be formed on the carrier sheet  210  by printing (for example, by screen printing), or the three adhesion methods may be used in a combined manner, so as to form the conductive line layer  220  on the carrier sheet  210 . 
     The conductive line layer  220  of the present invention is formed on the carrier sheet  210  by using the above adhesion methods, and persons skilled in the art may also use techniques suitable for forming the conductive line layer  220  on the carrier sheet  210 , which is not limited by this embodiment. 
     In addition, the conductive line layer  220  of the present invention is formed of at least one conductive ink, and the conductive line layer  220  according to this embodiment is formed by stacking multiple layers of conductive inks of different materials. However, persons skilled in the art may correspondingly increase or decrease the number of layers of the conductive inks of the present invention according to practical design requirements, which is not limited to this embodiment. 
     Referring to  FIGS. 1 and 2B , by an IMR process, the conductive line layer  220  is formed on a non-conductive substrate  240  (Step  110 ). Specifically, in this embodiment, a film feeding machine places the IMR material in a mold, and the carrier sheet  210  having the IMR material is adhered to a wall of the mold. The semi-liquid non-conductive substrate  240  is injected into the mold by injection molding, so as to be cured and formed on the adhesion layer  250  of the IMR material that the non-conductive substrate  240  is formed on one side of the IMR material near the conductive line layer  220 . The IMR material and the non-conductive substrate  240  are adhered to each other through a viscous force of the adhesion layer  250 . 
     In this embodiment, the non-conductive substrate  240  is made of resin, and is formed on the conductive line layer  220  by injection molding. However, persons skilled in the art may also use other suitable forming methods or materials to replace this embodiment, so, this embodiment is not limited thereto. 
     As shown in  FIGS. 1 and 2C , after the non-conductive substrate  240  is cured and formed on the IMR material, the non-conductive substrate  240  and the IMR material may be taken out from the mold. At the moment, a function of the release layer  260  is that after the IMR material adhered to the non-conductive substrate  240  by the injection molding, the carrier sheet  210  may be stripped from the hardening layer  230  through the release layer  260  (Step  120 ). That is to say, when film stripping is performed on a product during the IMR process, the hardening layer  230  is stripped from the carrier sheet  210  through the release layer  260 , and the hardening layer  230  is exposed and becomes an outside surface of the product. 
     It should be noted that, the IMR process according to the present invention only keeps the conductive line layer  220  inside the object  200  (that is, a casing of an electronic device), and the conductive line layer  220  and the object  200  form an integrally formed structure, which is different from an IMF process in which a whole mold film is placed in an object. 
     As shown in  FIGS. 1 and 2F , after the step of separating the carrier sheet  210  (Step  120 ) is completed, a connecting piece  270  is formed on the hardening layer  230  (Step  130 ). By a connection process, the connecting piece  270  runs through the hardening layer  230 , so that the connecting piece  270  is electrically connected to the conductive line layer  220  (Step  140 ). 
     Specifically, as shown in  FIGS. 2C to 2F , in this embodiment, the hardening layer  230  may be penetrated in a direction toward the conductive line layer  220  by etching, so that the conductive line layer  220  is partially exposed through a through hole  231 . A conductive material is filled into the through hole  231  to form an electrical pad  232 , and the connecting piece  270  is disposed on the hardening layer  230  and contacts the electrical pad  232 , so that the connecting piece  270  runs through the hardening layer  230  through the electrical pad  232 , and the connecting piece  270  is therefore electrically connected to the conductive line layer  220 . Therefore, the structure of the object having a conductive line  200  is formed. The connecting piece  270  and the electrical pad  232  may be electrically connected to each other by soldering, but the present invention is not limited thereto. 
     Alternatively, in this embodiment, for the connecting piece  270 , the hardening layer  230  may be penetrated in the direction toward the conductive line layer  220  by mechanical perforation, so that the conductive line layer  220  is partially exposed through the through hole  231 . Next, a conductive material is filled into the through hole  231  to form the electrical pad  232 , and the connecting piece  270  is disposed on the hardening layer  230  and contacts the electrical pad  232 , so that the connecting piece  270  runs through the hardening layer  230  through the electrical pad  232 , and the connecting piece  270  is therefore electrically connected to the conductive line layer  220 . Therefore, the structure of the object having a conductive line  200  is formed. The connecting piece  270  and the electrical pad  232  may be electrically connected to each other by soldering, but the present invention is not limited thereto. 
     It should be noted that, in this embodiment, the connection methods are not limited to the etching method or the mechanical perforation method, and persons skilled in the art may select any suitable chemical or mechanical method to make the connecting piece  270  run through the hardening layer  230  to be electrically connected to the conductive line layer  220 . 
     Alternatively, as shown in  FIGS. 3A to 3D , in the present invention, the connecting piece  270  and the conductive line layer  220  are electrically connected to each other by the following method. The hardening layer  230  and the electrical pad  232  are formed at the same time by an insert molding process. The electrical pad  232  is partially exposed from the hardening layer  230 , the conductive line layer  220  is formed on the hardening layer  230  by the IMR process, the conductive line layer  220  contacts the electrical pad  232 , the connecting piece  270  is disposed on the electrical pad  232 , and the connecting piece  270  contacts the electrical pad  232 , so that the connecting piece  270  runs through the hardening layer  230  through the electrical pad  232 , and the connecting piece  270  is electrically connected to the conductive line layer  220 . The connecting piece  270  and the electrical pad  232  may be electrically connected to each other by soldering, but the present invention is not limited thereto. 
     In addition, although the connecting piece  270  according to this embodiment is illustrated as a connector, the connecting piece  270  according to the present invention needs only to be an electronic component capable of transmitting an electrical signal, such as a cable or a flexible line, but the present invention is not limited thereto. 
     As shown in  FIGS. 2F and 4 , the manufacturing method of the present invention is applicable to forming a conductive line on a casing of an electronic device. When the conductive line according to the present invention is formed and disposed on an inner side surface (also called a male mold surface) of an electronic device casing  300 , the connecting piece  270  is electrically connected to the conductive line layer  220  and a circuit board  310  in the electronic device casing  300  respectively, so that the conductive line layer  220  is electrically connected to the circuit board  310 . Since in this embodiment, the connecting piece  270  is hidden inside the electronic device casing  300 , no additional protective element is required to protect the connecting piece  270 . 
       FIG. 5  is a flow chart according to a second embodiment of the present invention,  FIG. 6  is schematic sectional view according to the second embodiment of the present invention, and  FIG. 7  is a plane side view according to the second embodiment of the present invention. Since processing steps and a structure in the second embodiment are substantially the same as those in the first embodiment, only the differences are described herein. 
     As shown in  FIGS. 5 and 6 , after the step in which the connecting piece  270  runs through the hardening layer  230  (Step  140 ), the second embodiment of the present invention further comprises a step of forming a protective element  280  covering the connecting piece  270  (Step  150 ). 
     As shown in  FIGS. 7 ,  5 , and  6 , the manufacturing method of the present invention is applicable to forming a conductive line on a casing of an electronic device. When the conductive line according to the present invention is formed and disposed on an outer side surface (also called a female mold surface) of the electronic device casing  300 , the connecting piece  270  is electrically connected to the conductive line layer  220  and the circuit board  310  in the electronic device casing  300  respectively, so that the conductive line layer  220  is electrically connected to the circuit board  310 . 
     Since the connecting piece  270  in this embodiment is disposed outside the electronic device casing  300  and is exposed, the protective element  280  is required to be disposed additionally for the connecting piece  270  to protect the connecting piece  270 , thus preventing the connecting piece  270  from losing an electrical connection function thereof due to pollution of external dust and water. 
     In view of the above, in the present invention, in the manufacturing method of the object having a conductive line, the conductive line layer is integrally formed in the structure of the object (the casing of an electronic device) by the IMR process, which is very applicable to manufacturing of a casing structure having a complicated appearance. In addition, advantages of the IMR process are that the IMR process has a high degree of automation, and is capable of mass production, thus simplifying processing procedures, lowering manufacturing cost, and increasing a manufacturing yield rate.