Patent Publication Number: US-2009225491-A1

Title: Metallized film capacitor

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a metallized film capacitor, and more particularly to a metallized film capacitor including an increased capacitance without increasing the size or the volume of the metallized film capacitor and without complicating the metallized film capacitor. 
     2. Description of the Prior Art 
     Typical metallized film capacitors comprise a number of insulating foil film segments coated with metal electrode layers on each surface, and a number of insulation foil films disposed between the insulating foil film, and metal contact layers disposed in contact with the electrode segment groups of the foil film segments. 
     For example, U.S. Pat. No. 4,434,452 to Hamabe et al. discloses one of the typical metallized film capacitors comprising a number of insulating foil films and insulation foil films alternatively superposed with each other, and evaporated electrode layers applied onto the insulating foil films. 
     However, no evaporated electrode layers have been applied onto the insulation foil films such that the capacitance for the typical metallized film capacitor is limited or may not be increased, and the sizes or the volumes of the typical metallized film capacitors will be increased. 
     U.S. Pat. No. 5,608,600 to Lavene discloses another typical metallized film capacitor comprising two or more elongated dielectric webs each having electrodes metallized on an upper face thereof and each having one or more portions different in thickness from each other. 
     However, the electrodes are metallized on the upper face of each of the elongated dielectric webs, or metallized on both faces of one of two elongated dielectric webs such that the capacitance for the typical metallized film capacitor is also limited or may not be increased. 
     U.S. Pat. No. 5,905,628 to Okuno et al. discloses a further typical metallized film capacitor also comprising two or more plastic films each having evaporated electrodes metallized on an upper face thereof, the electrodes each include a high resistance area and a low resistance area having different in thickness from each other. 
     However, similarly, the electrodes are metallized on the upper face of each of the plastic films such that the capacitance for the typical metallized film capacitor is also limited or may not be increased. 
     U.S. Pat. No. 7,027,286 to Shiota et al. discloses a still further typical metallized film capacitor also comprising two or more dielectric films each having two or more or divisional and evaporated electrodes metallized on an upper face of each of the dielectric films and each having a slit formed between every two adjacent evaporated electrodes. 
     However, similarly, the electrodes are metallized on the upper face of each of the dielectric films such that the capacitance for the typical metallized film capacitor is also limited or may not be increased. 
     The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional metallized film capacitors. 
     SUMMARY OF THE INVENTION 
     The primary objective of the present invention is to provide a metallized film capacitor including an increased capacitance without increasing the size or the volume of the metallized film capacitor and without complicating the structure of the metallized film capacitor. 
     In accordance with one aspect of the invention, there is provided a metallized film capacitor comprising at least one capacitor unit including a first insulating substrate and a second insulating substrate, the first and the second insulating substrates each including a first surface and a second surface, a first electrode layer applied onto the first surface of the first insulating substrate and including an end terminal extended toward an end portion of the first insulating substrate, a second electrode layer applied onto the second surface of the second insulating substrate and including an end terminal extended toward an end portion of the second insulating substrate, a third electrode layer applied onto the second surface of the first insulating substrate and including an end terminal extended toward another end portion of the first insulating substrate, and a fourth electrode layer applied onto the first surface of the second insulating substrate and including an end terminal extended toward another end portion of the second insulating substrate for suitably increasing the capacitance of the capacitor unit without increasing the size or the volume of the metallized film capacitor and without complicating the structure of the metallized film capacitor. 
     The capacitor unit includes a first metallized contact and a second metallized contact, the end terminals of the first and the second electrode layers are extended toward the first metallized contact, and the end terminals of the third and the fourth electrode layers are extended toward the second metallized contact. 
     The first surface of the first and the second insulating substrates is an upper surface, and the second surface of the first and the second insulating substrates is a lower surface. 
     The first electrode layer, the second electrode layer, the third electrode layer, and the fourth electrode layer each may include one or more electrode segments divided or separated from each other. 
     A metallized film capacitor comprising at least one capacitor unit including a first insulating substrate and a second insulating substrate, the first and the second insulating substrates each including a first surface and a second surface, a first electrode layer applied onto the first surface of the first insulating substrate and including two end terminals extended toward end portions of the first insulating substrate, a second electrode layer applied onto the second surface of the second insulating substrate and including two end terminals extended toward end portions of the second insulating substrate, a third electrode layer applied onto the second surface of the first insulating substrate, and a fourth electrode layer applied onto the first surface of the second insulating substrate. 
     The capacitor unit includes a first metallized contact and a second metallized contact, the end terminals of the first and the second electrode layers are extended toward the first and the second metallized contacts. 
     Further objectives and advantages of the present invention will become apparent from a careful reading of the detailed description provided hereinbelow, with appropriate reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial cross sectional view of a metallized film capacitor in accordance with the present invention; 
         FIG. 2  is another partial cross sectional view illustrating a portion of the metallized film capacitor; 
         FIG. 3  is a further partial cross sectional view illustrating the other arrangement of the metallized film capacitor; 
         FIG. 4  is a still further partial cross sectional view illustrating the further arrangement of the metallized film capacitor; 
         FIG. 5  is a still further partial cross sectional view illustrating the still further arrangement of the metallized film capacitor; and 
         FIG. 6  is a still further partial cross sectional view illustrating the still further arrangement of the metallized film capacitor. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, and initially to  FIGS. 1 and 2 , a metallized film capacitor  1  in accordance with the present invention comprises one or more capacitor units  10  superposed with each other or one disposed above the other as shown in  FIG. 1 , and the capacitor units  10  each include two dielectric or insulating films or substrates  11 ,  21  made of polypropylene or polyethylene or other synthetic materials and superposed with each other, and each substrate  11 ,  21  having two surfaces  12 ,  13 ;  22 ,  23 , such as a first or upper surface  12 ,  22  and a second or lower surface  13 ,  23 , in which the ends of the insulating substrates  11 ,  21  are extended toward or engaged into two metallized contacts  80 ,  88  respectively as shown in dotted lines in  FIGS. 1 and 2 . 
     An evaporated electrode layer  30  is applied onto one of the surfaces  12 , such as the upper surface  12  of one of the insulating films or substrates  11  and includes one end or terminal  31  extended toward and/or flush with one end portion of the insulating substrate  11  and extended toward one of the metallized contacts  80  and/or coupled to the first metallized contact  80 , and a further or another evaporated electrode layer  40  is applied onto the other or the second or the lower surface  23  of the other insulating substrate  12  and includes one end or terminal  41  extended toward and/or flush with one end portion of the insulating substrate  12  and extended toward the first metallized contact  80  and/or coupled to the first metallized contact  80 . 
     A still further evaporated electrode layer  50  is applied onto the other or the second or the lower surface  13  of the insulating substrate  11  and includes one end or terminal  51  extended toward and/or flush with the other end portion of the insulating substrate  11  and extended toward the other or the second metallized contact  88  and/or coupled to the second metallized contact  88 , and a still further evaporated electrode layer  60  is applied onto the upper surface  22  of the insulating substrate  21  and includes one end or terminal  61  extended toward and/or flush with the other end portion of the insulating substrate  12  and extended toward the second metallized contact  88  and/or coupled to the second metallized contact  88 , in which the end terminals  31 ,  41 ,  51 ,  61  of the evaporated electrode layers  30 ,  40 ,  50 ,  60  may include a uniform thickness equals to that of the respective evaporated electrode layers  30 ,  40 ,  50 ,  60  as shown in  FIGS. 1 and 2 . 
     The evaporated electrode layers  30 ,  40 ,  50 ,  60  may be made of zinc, aluminum, graphite, metals, alloys, or other conductive or semi-conductive materials, and the insulating substrates  11 ,  21  each include two evaporated electrode layers  30 ,  50 ;  40 ,  60  metallized or applied onto the two opposite surfaces  11 ,  12 ;  21 ,  22  thereof for allowing the capacitance of the capacitor units  10  to be suitably increased without increasing the size or the dimension or the volume of the metallized film capacitor  1  and without complicating the structure of the metallized film capacitor  1 , and without spoiling the structure of the metallized film capacitor  1 , or without decreasing the strength of the metallized film capacitor  1 . 
     Alternatively, as shown in  FIG. 3 , the end terminals  310 ,  410 ,  510 ,  610  of the evaporated electrode layers  301 ,  401 ,  501 ,  601  may include a thickness greater than that of the evaporated electrode layers  301 ,  401 ,  501 ,  601  for increasing the attachment or the coupling of the end terminals  310 ,  410 ,  510 ,  610  of the evaporated electrode layers  301 ,  401 ,  501 ,  601  to the metallized contacts  80 ,  88  respectively. 
     Further alternatively, as shown in  FIG. 4 , the evaporated electrode layers  302 ,  402 ,  502 ,  602  each may be separated or divided into two or more electrode segments  32 ,  33 ,  42 ,  43 ,  52 ,  53 ,  62 ,  63  or each may include two or more electrode segments  32 ,  33 ,  42 ,  43 ,  52 ,  53 ,  62 ,  63 . 
     Further alternatively, as shown in  FIG. 5 , the evaporated electrode layers  303 ,  403  each may include two electrode segments  32 ,  33 ,  42 ,  43 , and each may include two end terminals  31 ,  34 ;  41 ,  44  extended out of the insulating substrates  11 ,  12  and extended toward the metallized contacts  80 ,  88  and/or coupled to the metallized contacts  80 ,  88  respectively, and the evaporated electrode layers  503 ,  603  each may include a one-integral piece or structure having no end terminals extended out of the insulating substrates  11 ,  12 . 
     Further alternatively, as shown in  FIG. 6 , the evaporated electrode layers  304 ,  404  each may include three or more electrode segments  32 ,  33 ,  36 ;  42 ,  43 ,  46  and each may include two end terminals  31 ,  34 ;  41 ,  44  extended out of the insulating substrates  11 ,  12  and extended toward the metallized contacts  80 ,  88  and/or coupled to the metallized contacts  80 ,  88  respectively. 
     Accordingly, the metallized film capacitor in accordance with the present invention includes an increased capacitance without increasing the size or the volume of the metallized film capacitor and without complicating the structure of the metallized film capacitor. 
     Although this invention has been described with a certain degree of particularity, it is to be understood that the present disclosure has been made by way of example only and that numerous changes in the detailed construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.