Patent Publication Number: US-2009236772-A1

Title: Pattern transfer mold and pattern transfer method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 97109911, filed on Mar. 20, 2008. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a pattern transfer technology, in particular, to a pattern transfer mold and a pattern transfer method for decorating a surface. 
     2. Description of Related Art 
     Pattern transfer technologies have been widely used for decorating product appearances and marking the products. For the purpose of decorating the product appearances and marking the products, a variety of pattern transfer technologies such as screen printing, spray painting, and in-mold roller (IMR) have been developed and used currently, in which the thermal transfer technology is more widely used for decorating the product appearances. 
     In a thermal transfer technology in the conventional art, firstly, a film having a decorative pattern thereon is disposed on a workpiece and fixed on a surface of the workpiece. Then, a roller is rolled on the surface of the workpiece to heat the film, thereby transferring the decorative pattern on the film to the surface of the workpiece. 
     Although the thermal transfer technology has become one of the widely accepted decoration technologies, it still has some deficiencies. For example, since the thermal transfer technology uses the roller to heat the film, the working area is merely limited to the area that is covered by the roller. Moreover, since the roller must contact the film in order to heat the film, the roller may cause damages to the surface of the workpiece when it contacts the surface of the workpiece. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a pattern transfer mold, suitable for closely attaching a film to a surface of a workpiece. 
     The present invention is also directed to a pattern transfer method, suitable for transferring a decorative pattern on a film to a workpiece. 
     As embodied and broadly described herein, the present invention provides a pattern transfer mold, suitable for transferring at least one decorative pattern of a film to at least one workpiece. The pattern transfer mold includes a mold base and a mold core. The mold base has a mold cavity and an air vent associated with the mold cavity. The mold core is inserted in the mold cavity of the mold base and has an upper surface and a plurality of upper air grooves on the upper surface. The mold cavity and the mold core have a plurality of mold air channels located between the mold cavity and the mold core. The upper air grooves are associated with the air vent via the mold air channels. 
     In an embodiment of the present invention, the mold core has a plurality of mold protrusions. The mold protrusions are protruded from the upper surface of the mold core and are provided for a plurality of workpieces to be mounted thereon respectively. One of the upper air grooves is located between two adjacent mold protrusions. 
     In an embodiment of the present invention, the air vent is associated with the mold cavity via a bottom surface of the mold cavity. 
     In an embodiment of the present invention, the mold air channels include a plurality of side air channels and a plurality of lower air channels. The side air channels are located between an inner side surface of the mold cavity adjacent to the bottom surface and an outer side surface of the mold core adjacent to the upper surface, and the lower air channels are located between the bottom surface of the mold cavity and a lower surface of the mold core opposite to the upper surface and adjacent to the outer side surface. 
     In an embodiment of the present invention, the mold cavity has a plurality of side air grooves. The side air grooves are located at the inner side surface of the mold cavity and constitute the side air channels together with the outer side surface of the mold core. 
     In an embodiment of the present invention, the mold core has a plurality of side air grooves. The side air grooves are located at the outer side surface of the mold core and constitute the side air channels together with the inner side surface of the mold cavity. 
     In an embodiment of the present invention, the mold cavity has a plurality of lower air grooves. The lower air grooves are located at the bottom surface of the mold cavity and constitute the lower air channels together with the lower surface of the mold core. 
     In an embodiment of the present invention, the mold core has a plurality of lower air grooves. The lower air grooves are located at the lower surface of the mold core and constitute the lower air channels together with the bottom surface of the mold cavity. 
     In an embodiment of the present invention, the mold base has a plurality of positioning columns, and the film has a plurality of positioning holes. The film may be positioned on the mold base, the mold core, and the workpiece by means of fitting the positioning columns into the positioning holes respectively. 
     The present invention further provides a pattern transfer method, suitable for transferring at least one decorative pattern on a film to at least one workpiece. The pattern transfer method includes the following steps: providing a mold base and a mold core; disposing a workpiece on an upper surface of the mold core; positioning a film on the mold base, the mold core, and the workpiece; extracting air from a space between the film and the workpiece through an air vent, mold air channels, and upper air grooves; and heating the decorative pattern. 
     In the step of providing the mold base and the mold core, the mold base has a mold cavity and an air vent associated with the mold cavity. The mold core is inserted in the mold cavity of the mold base and has an upper surface exposed out of the mold cavity and a plurality of upper air grooves on the upper surface. The mold cavity and the mold core have a plurality of mold air channels located there-between. The upper air grooves are associated with the air vent via the mold air channels. 
     In the step of positioning the film on the mold base, the mold core, and the workpiece, the film has a first surface, a second surface opposite to the first surface, and at least one decorative pattern on the first surface. The first surface of the film faces the workpiece. The air is extracted from the space between the film and the workpiece via the air vent, the mold air channels, and the upper air grooves to apply a negative air pressure to the first surface of the film, so as to closely attach the film to the workpiece. Then, the decorative pattern is heated, thereby transferring the decorative pattern from the film to the workpiece. 
     In an embodiment of the present invention, the pattern transfer method further includes applying a positive air pressure to the second surface of the film, so as to closely attach the film to the workpiece. 
     In an embodiment of the present invention, the step of disposing the workpiece further includes mounting the workpiece on at least one mold protrusion of the mold core protruded from the upper surface. 
     In an embodiment of the present invention, the step of positioning the film further includes respectively fitting a plurality of positioning columns of the mold base into a plurality of positioning holes of the film. 
     In the present invention, since the upper air grooves are associated with the air vent via the mold air channels, when extracting the air through the air vent and heating the film, the film can be uniformly and closely attached to the workpiece, so as to transfer the decorative pattern on the film to the workpiece, thereby avoiding the damages on the surface of the workpiece caused by heating with a roller in the prior art when contacting the surface of the workpiece by the roller. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1A  is a schematic exploded view of a pattern transfer mold for transferring a decorative pattern of a film to a workpiece according to an embodiment of the present invention. 
         FIG. 1B  is a cross-sectional view of the pattern transfer mold as shown in  FIG. 1A  for transferring the decorative pattern of the film to a workpiece. 
         FIG. 2  is a schematic horizontal cross-sectional view of a pattern transfer mold according to another embodiment of the present invention. 
         FIG. 3  is a schematic horizontal cross-sectional view of a pattern transfer mold according to another embodiment of the present invention. 
         FIG. 4  is a schematic vertical cross-sectional view of a pattern transfer mold according to another embodiment of the present invention. 
         FIG. 5  is a schematic vertical cross-sectional view of a pattern transfer mold according to another embodiment of the present invention. 
         FIGS. 6A to 6D  show a flow chart of a pattern transfer method according to the present invention. 
         FIG. 7  is a partial schematic view of a pattern transfer mold and a workpiece according to another embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
       FIG. 1A  is a schematic exploded view of a pattern transfer mold for transferring a decorative pattern of a film to a workpiece according to an embodiment of the present invention, and  FIG. 1B  is a schematic cross-sectional view of the pattern transfer mold as shown in  FIG. 1A  for transferring the decorative pattern of the film to the workpiece. Referring to  FIGS. 1A and 1B , in this embodiment, a pattern transfer mold  100  is suitable for transferring at least one decorative pattern  210   a  of a film  200  to at least one workpiece  300 . The decorative pattern  210   a  is, for example, an icon, a symbol, a letter, or a figure. 
     The pattern transfer mold  100  includes a mold base  110  and a mold core  120 . The mold base  110  has a mold cavity  112  and an air vent  114  associated with the mold cavity  112 . The mold core  120  is inserted in the mold cavity  112  of the mold base  110  and has an upper surface  122   a  and a plurality of upper air grooves  124   a  on the upper surface  122   a.    
     The mold cavity  112  and the mold core  120  have a plurality of mold air channels  128  located between the mold cavity  112  and the mold core  120 . The upper air grooves  124   a  are associated with the air vent  114  via the mold air channels  128 . In this embodiment, the air vent  114  is associated with the mold cavity  112  via a bottom surface  112   a  of the mold cavity  112 . Moreover, the mold core  120  has a plurality of mold protrusions  126  (only four mold protrusions are schematically shown in  FIG. 1B ). The mold protrusions  126  are protruded out of the upper surface  122   a  of the mold core  120  and are provided for a plurality of workpieces  300  (only four workpieces are schematically shown in  FIG. 1B ) to be mounted thereon. One of the upper air grooves  124   a  is located between two adjacent mold protrusions  126 . 
     In particular, referring to  FIG. 1B , the mold air channels  128  include a plurality of lower air channels  128   a  and a plurality of side air channels  128   b.  The side air channels  128   b  are located between an inner side surface  112   d  of the mold cavity  112  adjacent to the bottom surface  112   a  and an outer side surface  122   c  of the mold core  120  adjacent to the upper surface  122   a.  The lower air channels  128   a  are located between the bottom surface  112   a  of the mold cavity  112  and a lower surface  122   b  of the mold core  120  opposite to the upper surface  122   a  and adjacent to the outer side surface  122   c.    
     Referring to  FIG. 1A , the mold base  110  has a plurality of positioning columns  116  (only four positioning columns are schematically shown in  FIG. 1A ), and the film  200  has a plurality of positioning holes  230  (only four positioning holes are schematically shown in  FIG. 1A ). The film  200  can be positioned on the mold base  110 , the mold core  120 , and the workpiece  300  by means of fitting the positioning columns  116  into the positioning holes  230  respectively. 
     In short, since the pattern transfer mold  100  of this embodiment has a plurality of upper air grooves  124   a  and a plurality of mold air channels  128 , when extracting the air from the space between the film  200  and the workpiece  300  through the air vent  114 , the mold air channels  128 , and the upper air grooves  124   a,  the film  200  is moved towards the workpiece  300  and thus uniformly and evenly attached to the workpiece  300  closely. Moreover, the film  200  is heated, so as to transfer the decorative pattern  210   a  on the film  200  to the workpiece  300 , thereby avoiding the damages on the surface of the workpiece  300  caused by heating with a roller in the prior art when contacting the surface of the workpiece by the roller. 
       FIG. 2  is a schematic horizontal cross-sectional view of a pattern transfer mold according to another embodiment of the present invention. Referring to  FIGS. 1B  and  2 , in this embodiment, a pattern transfer mold  100   a  of  FIG. 2  is similar to the pattern transfer mold  100  of  FIG. 1B , but differs in that, the mold cavity  112  in this embodiment has a plurality of side air grooves  112   c  (only two side air grooves are schematically shown in  FIG. 2 ). The side air grooves  112   c  are located at the inner side surface  112   d  of the mold cavity  112  and constitute the side air channels  128   b  together with the outer side surface  122   c  of the mold core  120 . 
       FIG. 3  is a schematic horizontal cross-sectional view of a pattern transfer mold according to another embodiment of the present invention. Referring to  FIGS. 1B and 3 , in this embodiment, a pattern transfer mold  100   b  of  FIG. 3  is similar to the pattern transfer mold  100  of  FIG. 1B , but differs in that, the mold core  120  in this embodiment has a plurality of side air grooves  124   c  (only two side air grooves are schematically shown in  FIG. 3 ). The side air grooves  124   c  are located at the outer side surface  122   c  of the mold core  120  and constitute the side air channels  128   b  together with the inner side surface  112   d  of the mold cavity  112 . 
       FIG. 4  is a schematic vertical cross-sectional view of a pattern transfer mold according to another embodiment of the present invention. Referring to  FIGS. 1B and 4 , in this embodiment, a pattern transfer mold  100   c  of  FIG. 4  is similar to the pattern transfer mold  100  of  FIG. 1B , but differs in that, the mold cavity  112  (referring to  FIG. 1B ) in this embodiment has a plurality of lower air grooves  112   b  (only two lower air grooves are schematically shown in  FIG. 4 ). The lower air grooves  112   b  are located at the bottom surface  112   a  of the mold cavity  112  and constitute the lower air channels  128   a  together with the lower surface  122   b  of the mold core  120 . 
       FIG. 5  is a schematic vertical cross-sectional view of a pattern transfer mold according to another embodiment of the present invention. Referring to  FIGS. 1B  and  5 , in this embodiment, a pattern transfer mold  100   d  of  FIG. 5  is similar to the pattern transfer mold  100  of  FIG. 1B , but differs in that, the mold core  120  in this embodiment has a plurality of lower air grooves  124   b  (only two lower air grooves are schematically shown in  FIG. 5 ). The lower air grooves  124   b  are located at the lower surface  122   b  of the mold core  120  and constitute the lower air channels  128   a  together with the bottom surface  112   a  of the mold cavity  112  (referring to  FIG. 1B ). 
       FIGS. 6A to 6D  show a flow chart of a pattern transfer method according to the present invention. Referring to  FIG. 6A , in the pattern transfer method, a mold base  110  and a mold core  120  are provided first. The mold base  110  and the mold core  120  constitute a pattern transfer mold  100 . The mold base  110  has a mold cavity  112  and an air vent  114  associated with the mold cavity  112 . The mold core  120  is inserted in the mold cavity  112  of the mold base  110  and has an upper surface  122   a  exposed out of the mold cavity  112  and a plurality of upper air grooves  124   a  on the upper surface  122   a.  The mold cavity  112  and the mold core  120  have a plurality of mold air channels  128  located there-between. The upper air grooves  124   a  are associated with the air vent  114  via the mold air channels  128 . 
     Referring to  FIG. 6B , a workpiece  300  is then disposed on the upper surface  122   a  of the mold core  120 , and a film  200  is positioned on the mold base  110 , the mold core  120 , and the workpiece  300 . The film  200  has a first surface  210 , a second surface  220  opposite to the first surface  210 , and at least one decorative pattern  210   a  on the first surface  210 . The first surface  210  of the film  200  faces the workpiece  300 . 
     In particular, the step of disposing the workpiece  300  further includes mounting the workpiece  300  on at least one mold protrusion  126  of the mold core  120  protruded from the upper surface  122   a.  The step of positioning the film  200  further includes respectively fitting a plurality of positioning columns  116  of the mold base  110  into a plurality of positioning holes  230  of the film  200  (referring to  FIG. 1A ), so as to position the film  200  on the mold base  110 , the mold core  120 , and the workpiece  300 . 
     Referring to  FIG. 6C , the air is extracted from a space between the film  200  and the workpiece  300  through the air vent  114 , the mold air channels  128 , and the upper air grooves  124   a  to apply a negative air pressure to the first surface  210  of the film  200 , such that the film  200  is moved towards the workpiece  300  and is thus evenly and closely attached to the workpiece  300 . 
     Referring to  FIG. 6D , finally, the decorative pattern  210   a  is heated. The second surface  220  of the film  200  is heated by a heat generator (not shown) to make the film  200  become flexible after being heated, so as to transfer the decorative pattern  210   a  to the workpiece  300 . In this embodiment, the pattern transfer method further includes applying a positive air pressure to the second surface  220  of the film  200  to closely attach the film  200  to the workpiece  300 , so as to uniformly transfer the decorative pattern  210   a  to the workpiece  300 . 
       FIG. 7  is a partial schematic view of a pattern transfer mold and a workpiece according to another embodiment of the present invention. Referring to  FIGS. 1A ,  1 B, and  7 , in this embodiment, a pattern transfer mold of  FIG. 7  is similar to the pattern transfer mold  100  of  FIG. 1B , but differs in that, the mold core  120  in this embodiment has an upper surface  122   a  and a plurality of upper air grooves  124   a,  and a workpiece  300 A is a thin flat plate disposed on the upper surface  122   a  of the mold core  120 . The plurality of upper air grooves  124   a  is located on the upper surface  122   a  and passes through the workpiece  300 A. In other words, the workpiece  300 A may span across the plurality of upper air grooves  124   a.    
     In particular, when extracting the air from the space between the film  200  and the workpiece  300 A through the air vent  114 , the mold air channels  128 , and the upper air grooves  124   a  (the air flow directions are marked by arrows in  FIG. 7 ), the film  200  is moved towards the workpiece  300 A and thus uniformly attached to the workpiece  300 A closely. Moreover, the film  200  is heated, so as to transfer the decorative pattern  210   a  on the film  200  to the workpiece  300 A. 
     To sum up, in the present invention, through extracting the air from the space between the film and the workpiece through the air vent, the upper air grooves, and the mold air channels to apply a negative air pressure to the first surface of the film, the film is moved towards the workpiece and thus closely attached to the workpiece. Moreover, the film is heated, so as to transfer the decorative pattern on the film to the workpiece, thereby avoiding the damages on the surface of the workpiece caused by a roller upon contacting the surface of the workpiece in the prior art. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.