Patent Publication Number: US-2015063749-A1

Title: Lens unit and optical communication device

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a lens unit and an optical communication device having the lens unit. 
     2. Description of Related Art 
     Optical communication devices include optical fibers, light-emitting units, a lens unit, and light-receiving units. The lens unit is configured for coupling the optical fibers to the light-emitting units and the light-receiving units 
     Light emitted by the light-emitting units travels a certain distance in the lens unit before being coupled to the optical fibers. Light emitted by the optical fibers travels the same distance in the lens unit before being coupled to the light-receiving units. Thus, the lens unit only allows the light to travel a same distance when it is emitted and received. When the optical communication device needs light to travel different distances in the lens unit, two or more lens units are needed, thereby increasing a size of the optical communication device. 
     Therefore, it is desirable to provide a lens unit and an optical communication device which can overcome the limitation described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components of the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout several views. 
         FIG. 1  is a schematic view of an embodiment of an optical communication device. 
         FIG. 2  is an exploded view of the optical communication device of  FIG. 1 . 
         FIG. 3  is another exploded view of the optical communication device of  FIG. 1 . 
         FIG. 4  is a front side view of the optical communication device of  FIG. 2 . 
         FIG. 5  is a back side view of the optical communication device of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-3  show an exemplary embodiment of an optical communication device  100 . The optical communication device  100  includes a lens unit  10 , a first optical fiber  20 , a second optical fiber  30 , a circuit board  40 , a first photoelectric unit  50 , and a second photoelectric unit  60 . 
     The circuit board  20  can be a hard circuit board or a flexible circuit board. The first photoelectric unit  50  and the second photoelectric unit  60  are located on and electrically connected to the circuit board  20 . In this embodiment, both the first photoelectric unit  50  and the second photoelectric unit  60  are light-emitting units. In other embodiment, both the first photoelectric unit  50  and the second photoelectric unit  60  are light-receiving units. In another embodiment, one of the first photoelectric unit  50  and the second photoelectric unit  60  is a light-emitting unit and the other one is a light-receiving unit. The light-emitting unit can be a light-emitting diode or a laser diode. The light-receiving unit is a photodiode. The lens unit  20  is configured for coupling the first optical fiber  20  to the first photoelectric unit  50 , and the second optical fiber  30  to the second photoelectric unit  60 . 
     The lens unit  10  includes a first portion  11  and a second portion  12 . The first portion  11  is configured for coupling the first optical fiber  20  to the first photoelectric unit  50 . The second potion  12  is configured for coupling the second optical fiber  30  to the second photoelectric unit  60 . 
     Referring to  FIGS. 4 and 5 , the first portion  11  and the second portion  12  share a common bottom surface  101  and a common first side surface  102 . The first side surface  102  is substantially perpendicular to the bottom surface  101 . The first side surface  102  defines a first lens  111  and a third lens  123 . An optical axis of the first lens  111  is substantially parallel to an optical axis of the third lens  123  and substantially perpendicular to the first side surface  102 . The bottom surface  101  defines a second lens  112  and a fourth lens  124 . An optical axis of the second lens  112  is substantially parallel to an optical axis of the fourth lens  124  and substantially perpendicular to the bottom surface  101 . The first lens  111  and the second lens  112  are located on the first portion  11 . The third lens  123  and the fourth lens  124  are located on the second portion  12 . 
     The first portion  11  also includes a first reflecting surface  110 . An included angle between the first reflecting surface  110  and the bottom surface  101  is about 45 degrees. An included angle between the first reflecting surface  110  and the first side surface  102  is also about 45 degrees. 
     The second portion  12  also includes a second side surface  103 , a second reflecting surface  120 , a third reflecting surface  121 , and a fourth reflecting surface  122 . The second side surface  103  is substantially parallel to the first side surface  102 . The second reflecting surface  120 , the third reflecting surface  121 , and the fourth reflecting surface  122  are between the first side surface  102  and the second side surface  103 . The second reflecting surface  120  is substantially perpendicular and connects to the third reflecting surface  121 . An included angle between the second reflecting surface  120  and the second side surface  103  is 135 degrees. The fourth reflecting surface  122  is substantially parallel to the third reflecting surface  121 . An included angel between the third reflecting surface  121  and the first side surface  102  is 135 degrees. The fourth reflecting surface  122  extends obliquely from the bottom surface  101  toward an inner middle space of the lens unit  10 . An included angle between the fourth reflecting surface  122  and the bottom surface  101  is about 45 degrees. 
     Referring to  FIG. 4 , light emitted by the first optical fiber  20  emits onto the first reflecting surface  110  of the first portion  11  through the first lens  111  of the first side surface  102 . After the light is reflected by the first reflecting surface  110 , the light exits from the first portion  11  through the second lens  112 . The first photoelectric unit  50  receives the light. 
     Referring to  FIG. 5 , light emitted by the second optical fiber  30  emits onto the fourth reflecting surface  122  of the second portion  12  through the third lens  123  of the first side surface  102 . The light is reflected onto the third reflecting surface  121 . The light is then reflected onto the second reflecting surface  120 , and subsequently reflected off the second reflecting surface  120  to exit from the second portion  12  through the fourth lens  124 . The second photoelectric unit  60  receives the light. 
     Light emitted by the first optical fiber  20  is reflected one time in the first portion  11  and is received by the first photoelectric unit  50 , but light emitted by the second optical fiber  30  is reflected three times in the second portion  12  and is received by the second photoelectric unit  60 . Thus, light emitted by the first optical fiber  20  and the second optical fiber  30  have different optical lengths. 
     In other embodiments, both the first photoelectric unit  50  and the second photoelectric unit  60  are light-emitting units. Light emitted by the first photoelectric unit  50  is emitted onto the first reflecting surface  110  through the second lens  112 . The light is reflected by the first reflecting surface  110  onto the first lens  111  to enter the first optical fiber  20 . Light emitted by the second photoelectric unit  60  enters the second portion  12  through the fourth lens  124 . The light is reflected by the second reflecting surface  120 , the third reflecting surface  121 , and the fourth reflecting surface  122  through the third lens  123  and onto the second optical fiber  30 . 
     It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being exemplary embodiments of the disclosure.