Patent Publication Number: US-2015062921-A1

Title: Light source device

Description:
BACKGROUND 
     1. Technical Field 
     The disclosure relates to light source devices, and particularly to a light source device with larger radiation angle. 
     2. Discussion of Related Art 
     Light emitting diodes&#39; (LEDs) many advantages, such as high luminosity, low operational voltage, low power consumption, compatibility with integrated circuits, faster switching, long term reliability, and environmental friendliness have promoted their wide use as a lighting source. 
     However, the conventional LED cannot have a wide illumination area even use with a diverging lens. The light having a large incidence angle on the light emerging face of the diverging lens, may be totally reflected backwardly into the diverging lens. Thus, the radiation angle of the light emitted out of the diverging lens is limited, generally less than 120 degrees. In other words, the light intensity dramatically decreases when the radiation angle exceeds 120 degrees. 
     Therefore, what is needed is a light source device which can overcome the described limitations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the disclosure can be better understood with reference to the following drawing. The components in the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present light emitting diode device for microminiaturization. Moreover, in the drawing, like reference numerals designate corresponding parts throughout the whole view. 
         FIG. 1  is a schematic, isometric view of a light source device according to an exemplary embodiment. 
         FIG. 2  is an inverted view of a lens of the light source device of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the light source device of  FIG. 1 , taken along line III-III thereof. 
         FIG. 4  is a distribution graph of a radiation angle of the light source device of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Referring to  FIGS. 1-3 , a light source device  100  in accordance with an exemplary embodiment of the present disclosure is illustrated. The light source device  100  includes a light source  10  and a lens  20 . 
     The lens  20  includes a bottom surface  21 , a top surface  22  opposite to the bottom surface  21 , a light input surface  23  and a side surface  24  connected to the bottom surface  21  and the top surface  22 . The bottom surface  21  and the top surface  22  are planar surfaces and parallel to each other. In the present embodiment, the lens  20  is made of borosilicate glass. 
     The bottom surface  21  and the top surface  22  of the lens  20  are substantially circular. The light input surface  23  is defined at a center of the bottom surface  21  and depressing from the bottom surface  21  towards the top surface  21  of the lens  20 ; therefore, the bottom surface  21  defines a cavity  25  enclosed by the light input surface  23 . The light input surface  23  is an aspheric surface. 
     Referring to the  FIG. 3 , the side surface  24  connects the bottom surface  21  and the top surface  22 . The side surface  24  is a curved surface formed by rotating a curve line about a central/optical axis O 1 O 2  of the lens  20 . In the present embodiment, the side surface  24  is formed by rotating a semicircular line about the central/optical axis O 1 O 2  of the lens  20 . The top surface  22  and the side surface  24  act as the light output surface of the lens  20 . In the present embodiment, the side surface  24  smoothly connects the top surface  22  and the bottom surface  21 , and the side surface  24  has a diameter gradually increasing and then decreasing from the top surface  22  to the bottom surface  21 . 
     The light source  10  faces the light input surface  23  of the lens  20 . In the present embodiment, the light source  10  is received in the cavity  25  of the lens  20 . The light source  10  is an LED, and an optical axis of the light source  10  is coaxial to that of the lens  20 . A bottom surface  11  of the light source  10  is substantially coplanar with the bottom surface  21  of the lens  20 . In an alternatively embodiment, a light emitting surface of the light source  10  can be substantially coplanar with the bottom surface  21  of the lens  20 . 
     Referring to the  FIG. 4 , light beams emitted from the light source  10  travel through the light input surface  23  to enter the lens  20 , and are refracted and diverged by the top surface  22  and the side surface  24  of the lens to outside. Therefore, it can enhance the radiation angle of the light source device  100 . 
     It is to be further understood that even though numerous characteristics and advantages have been set forth in the foregoing description of embodiments, together with details of the structures and functions of the embodiments, the disclosure is illustrative only; and that changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.