Patent Publication Number: US-8523407-B2

Title: Optical element and illuminant device using the same

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an optical element, and in particular to an optical element which can enlarge light emitting angle of light. 
     2. Description of Prior Art 
     A light emitting diode (LED) is a kind of semiconductor device, which exploits the property of direct-bandgap semiconductor material to convert electric energy into light energy efficiently and has the advantages of long service time, high stability and low power consumption and is developed to replace the traditional non-directivity light tube and incandescent lamp. 
     The LED is a point-like light source and has high directivity so that the lighting surface of the LED is narrower than that of the traditional light sources, and the luminous intensity of the LED is gradually reduced while the lighting distance is increased, so that the LED is more suitable for providing short-distance and small area lighting fixture, such as table lamp. 
     In order to solve the mentioned problem, many manufacturers assemble and arrange multiple LEDs to centralize light for solving the problem of narrow lighting range. However, the required power for driving the LEDs is increased when the number of the LEDs is increased, therefore, the effect of saving energy cannot be achieved. Moreover, the price of LED lamp is far higher than the traditional light source so as to reduce the will of using LED lamp. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention provides an optical element, the optical element can effectively enlarge the emitting angle of light pass through the optical element. 
     The present invention further provides an illuminant device, the illuminant device provides a light with large emitting angle. 
     Therefore, the present invention provides an optical element, the optical element is assembled with a light emitting diode (LED) to form an illuminative light source. The optical element includes a transparent main body having a light guiding pillar and an extending part. The light guiding pillar has a top surface and a bottom surface opposite the top surface, the bottom surface has a recess. The extending part is extended from the circumference of the top surface and an end of the extending part has at least a light-emitting surface, wherein the LED is disposed on the recess and emits light to the optical element. 
     The present invention further provides an illuminant device, the illuminant device includes a circuit board, an LED, an optical element, a cover and a heat sink element. The LED is disposed on the circuit. The optical element includes a light guiding pillar and an extending part. The light guiding pillar has a top surface and a bottom surface opposite to the top surface. The bottom surface has a recess, the LED is disposed on the recess. The extending part is extended from the circumference of the top surface and an end of the extending part has a least a light-emitting surface. The cover is made of transparent material. The heat sink element is assembled with the cover such that the LED and the optical element are arranged between the cover and the heat sink element. 
     The optical element of the present invention uses the extending part which is extended from the circumference of the top surface to guide the light entered the optical element so that the light can be refracted by the extending part or reflected to the light-emitting surface and emitting from the light-emitting surface to enlarge the light-emitting angle of light passed through the optical element. Moreover, charging an included angle formed between the light-emitting surface and the bottom surface can provide different forms of luminous intensity distribution such that the optical element can apply in different lighting field. 
    
    
     
       BRIEF DESCRIPTION OF DRAWING 
       The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself, however, may be best understood by reference to the following detailed description of the invention, which describes an exemplary embodiment of the invention, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view of an optical element according to a first preferred embodiment of the present invention. 
         FIG. 2  is another perspective view of the optical element according to the first preferred embodiment of the present invention. 
         FIG. 3  is a sectional view of the optical element according to the first preferred embodiment of the present invention. 
         FIG. 4  is a schematic view of the luminous intensity distribution of the optical element according to the present invention. 
         FIG. 5  is a sectional view of an illuminant device according to the present invention. 
         FIG. 6  is a sectional view of an optical element according to a second preferred embodiment of the present invention. 
         FIG. 7  is a sectional view of an optical element according to a third preferred embodiment of the present invention. 
         FIG. 8  is a schematic view of the luminous intensity distribution of the optical element according to the present invention. 
         FIG. 9  is a perspective view of an optical element according to the fourth preferred embodiment of the present invention. 
         FIG. 10  is a sectional view of the optical element according to the fourth preferred embodiment of the present invention. 
         FIG. 11  is a perspective view of an optical element according to the fifth preferred embodiment of the present invention. 
         FIG. 12  is a sectional view of the optical element according to the fifth preferred embodiment of the present invention. 
         FIG. 13  is a perspective view of an optical element according to a sixth preferred embodiment of the present invention. 
         FIG. 14  is a sectional view of the optical element according to the sixth preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A preferred embodiment of the present invention will be described with reference to the drawings. 
     Reference is made to  FIG. 1  and  FIG. 2 , which are perspective views of an optical element from different view angles according to a first preferred embodiment of the present invention. The optical element  10  is applied for disposing on a light emitting diode (LED)  90  such that the luminous intensity distribution of light emitted by the LED can be changed and the emitting angle of the light can be enlarged. The LED  90  is, but not limited to, a LED chip, other equivalent elements can be used without departing from the scope of the present invention. 
     The optical element  10  can be integrally-formed by plastic, glass, silicon rubber, silicon resin or other light transparent material by injection molding. The optical element  10  has a transparent main body  11 . The main body  11  includes a light guiding pillar  12  and an extending part  14 . In this embodiment, the light guiding pillar  12  is, but not limited to, a cylinder. In the practical application, the light guiding pillar can be a triangular prism, a tetragonal prism or polygonal prisms. The light guiding pillar  12  has a top surface  120  and a bottom surface  122  opposite to the top surface  120 . The bottom surface  122  is designed as a plane and has a recess  124 . In this embodiment, the recess  124  disposed on the central of the bottom surface  122  is concave toward the top surface  120  and an opening of the recess  124  is of circular shape. In the practical application, the opening can be any geometric form. The LED  90  is disposed on the recess  124  and emits light to the optical element  10 . 
     The extending part  14  having a plurality of light guide strips  142  is connected to the light guiding pillar  12  and extended from the circumference of the top surface  120 . Multiple light-emitting surfaces  140  are disposed on the end of the light guide strips  142 . An included angle θ is formed between the light-emitting surface  140  and the bottom surface  122 . In this embodiment, the included angle θ is an obtuse angle, which is larger than ninety degrees. 
     In the practical application, the LED  90  is disposed in the recess  124  and emits light to the optical element  10 . The light is guided by the light guiding pillar  12  and emits to the top surface  120  and the extending part  14  by refraction or emits form the light-emitting surface  140  by reflecting by the extending part  14 . The extending part can effectively guide light to the light-emitting surface  140  to enhance the light-emitting angle. The luminous intensity distribution of the optical element  10  is shown in  FIG. 4 . 
     Reference is made to  FIG. 4 , which is a schematic view of the luminous intensity distribution of the optical element according to the present invention. The luminous intensity of the light pass through the optical element  10  distributes in 180 degrees from the both side of an optical axis. In more particularly, the luminous intensity is uniform distribution between 0 and 130 degrees and the luminous intensity between 130 and 180 degrees is larger than the 5 percent of the total luminous intensity. As shows in  FIG. 4 , the optical element  10  can effectively enlarge the emitting angle of the light and enhance the uniformity of light. 
     Reference is made to  FIG. 5 , which is a sectional view of an illuminant device according to the present invention. The illuminant device  80  includes a circuit board  82 , an LED  90 , an optical element  10 , a cover  84 , a heat sink element  86  and a conductive connector  88 . The LED  90  is disposed on the circuit board  82  and electrically connected thereto. In this embodiment, the circuit board  82  is provided with conductive traces (not shown) and soldering pads (not shown) thereon to mount the LED  90 . The LED  90  is, but not limited to, an LED chip. 
     The optical element  10  is disposed on the circuit board  82  and located on the LED  90 . With reference again to  FIG. 3 , the optical element  10  has a transparent main body  11  including a light guide pillar  12  and an extending part  14 . The light guide pillar  12  is, but not limited to, a cylinder. The light guide pillar  12  has a top surface  120  and a bottom surface  122 . The bottom surface  122  is a plane and has a recess  124 . In this embodiment, the recess  124  disposed on the central of the bottom surface  122  is concave toward the top surface  120  and an opening of the recess  124  is, but not limited to, of circular shape. The LED  90  is disposed on the recess  124  and emits light to the optical element  10 . The extending part  14  having a plurality of light guide strips  142  is connected to the light guiding pillar  12  and extended from the circumference of the top surface  120 . Multiple light-emitting surfaces  140  are disposed on the end of the light guide strips  142 . An included angle θ is formed between the light-emitting surface  140  and the bottom surface  122 . In this embodiment, the included angle θ is an obtuse angle, which is larger than ninety degrees. 
     With reference again to  FIG. 5 , the cover  84  is formed by light transparent material, and can be designed as transparent form or must form. The cover  84  encloses the circuit board  82 , which the LED  90  and the optical element  10  are disposed to prevent dust from attaching to the circuit board  84  and prevent moisture from permeating into the illuminant device  80 , thus enhancing the light efficiency and prolonging the lifetime of the illuminant device  80 . 
     The heat sink element  86  is assembled with the cover  84  such that the circuit board  82 , the LED  90  and the optical element  10  are arranged between the cover  84  and the heat sink element  86 . The heat sink element  86  can be made of material for fast removing the heat generated by lighting the LED  90 . 
     The conductive connector  88  is assembled to one side of the heat sink element  86 , which is opposite to the cover  84 , and electrically connected to the circuit board  82 . The conductive connector  88  can be, but not limited to, E 26  or E 27  connector. The conductive connector  88  is adapted to be connected into the socket of ordinary lamp and electrically connected to an external power. The power is transmitted to the circuit board  82  and lighting the LED  90  through the conductive connector  88 . The light emitted from the LED  90  transmits to the top surface  120  and the extending part  14  and emits form the top surface  120  or extending part  14  by refraction or emits form the light-emitting surface  140  by reflecting by the extending part  14 . 
     Reference is made to  FIG. 6 , which is a sectional view of an optical element according to a second preferred embodiment of the present invention. The optical element  20  has a transparent main body  21  and the main body  21  includes a light guide pillar  22  and an extending part  24 . The light guiding pillar  22  is, but not limited to, a circular pillar. The light guiding pillar  22  has a top surface  220  and a bottom surface  222  opposite to the top surface  220 . The top surface  220  is convex toward a direction which is opposite the bottom surface  222 , and the top surface  220  is, but not limited to, of arc convex, which can effectively enhance the uniformity of light emitted by the top surface  220 . The bottom surface  222  is a plane and has a recess  224 . The recess  224  disposed on the central of the bottom surface  222  is concave toward the top surface  220  and an opening of the recess  224  is, but not limited to, of circular shape. 
     The extending part  24  having a plurality of light guide strips  242  is connected to the light guiding pillar  22  and extended from the circumference of the top surface  220 . Multiple light-emitting surfaces  240  are disposed on the end of the light guide strips  242 . An included angle θ is formed between the light-emitting surface  240  and the bottom surface  222 . In this embodiment, the included angle θ is an obtuse angle, which is larger than ninety degrees. 
     The LED  90  is disposed on the recess  224  and emits light to the optical element  20 . The light transmits to the top surface  220  and the extending part  24  and emits form the top surface  220  or extending part  24  by refraction or emits form the light-emitting surface  240  through reflecting by the extending part  24 . 
     Reference is made to  FIG. 7 , which is a sectional view of an optical element according to a third preferred embodiment of the present invention. The optical element  30  has a transparent main body  31  and the main body  31  includes a light guide pillar  32  and an extending part  34 . The light guide pillar  32  is, but not limited to, a circular pillar. The light guiding pillar  32  has a top surface  320  and a bottom surface  322  opposite to the top surface  320 . The top surface  320  is concave toward the bottom surface  322  such that diverges light passed through and the top surface  320  is, but not limited to, of arc concave. The bottom surface  322  is a plane and has a recess  324 . The recess  324  disposed on the central of the bottom surface  322  is concave toward the top surface  320  and an opening of the recess  324  is, but not limited to, of circular shape. 
     The extending part  34  having a plurality of light guide strips  342  is connected to the light guiding pillar  32  and extended from the circumference of the top surface  320 . Multiple light-emitting surfaces  340  are disposed on the end of the light guide strips  342 . An included angle θ is formed between the light-emitting surface  340  and the bottom surface  322 . In this embodiment, the included angle θ is an obtuse angle, which is larger than ninety degrees. 
     The LED  90  is disposed on the recess  324  of the optical element  30 . Partial light emitted by the LED  90  and entered to the optical element  30  emits form the top surface  320 , the top surface  320  diverges the light. Other light emitted by the LED  90  and entered to the optical element  30  emits from the extending part  34  by refraction or emits form the light-emitting surface  340  through reflecting by the extending part  34 . The luminous intensity distribution of the optical element  30  is shown in  FIG. 8 , and the light focus at an inclined direction about 50 to 130 degrees at both side of an optical axis. 
     Reference is made to  FIG. 9  and  FIG. 10 , which are respectively a perspective view and a sectional view of an optical element according to the fourth preferred embodiment of the present invention. The optical element  40  has a transparent main body  41  including a light guide pillar  42  and an extending part  44 . The light guiding pillar  42  is, but not limited to, a cylinder. The light guiding pillar  42  has a top surface  420  and a bottom surface  422  opposite to the top surface  420 . The bottom surface  422  is a plane and has a recess  424 . The recess  424  disposed on the central of the bottom surface  422  is concave toward the top surface  420  and an opening of the recess  424  is, but not limited to, of circular shape. In this embodiment, the top surface  420  is a plane and is substantially parallel to the bottom surface  422 . In the practical application, the top surface  420  can be a convex face to enhance the uniformity of the light passed through or a concave face to converge the light passed through. 
     The extending part  44  having a plurality of light guide strips  442  is connected to the light guiding pillar  42  and extended from the circumference of the top surface  420 . Multiple light-emitting surfaces  440  are disposed on the end of the light guide strips  442 . An included angle θ is formed between the light-emitting surface  440  and the bottom surface  422 . In this embodiment, the included angle θ is a right angle, which is equal to ninety degrees. 
     Reference is made to  FIG. 11  and  FIG. 12 , which are respectively a perspective view and a sectional view of an optical element according to the fifth preferred embodiment of the present invention. The optical element  50  has a transparent main body  51  including a light guiding pillar  52  and an extending part  54 . The light guiding pillar  52  is, but not limited to, a cylinder. The light guiding pillar  52  has a top surface  520  and a bottom surface  522  opposite to the top surface  520 . The bottom surface  522  is a plane and has a recess  524 . The recess  524  disposed on the central of the bottom surface  522  is concave toward the top surface  520  and an opening of the recess  524  is, but not limited to, of circular shape. In this embodiment, the top surface  520  is a plane and is substantially parallel to the bottom surface  522 . In the practical application, the top surface  520  can be a convex face to enhance the uniformity of the light passed through or a concave face to converge the light passed through. 
     The extending part  54  having a plurality of light guide strips  542  is connected to the light guiding pillar  52  and extended from the circumference of the top surface  520 . Multiple light-emitting surfaces  540  are disposed on the end of the light guide strips  542 . An included angle θ is formed between the light-emitting surface  540  and the bottom surface  522 . In this embodiment, the included angle θ is an acute angle, which is smaller than ninety degrees. 
     Reference is made to  FIG. 13  and  FIG. 14 , which are respectively a perspective view and a sectional view of an optical element according to a sixth preferred embodiment of the present invention. The optical element  60  has a transparent main body  61  including a light guiding pillar  62  and an extending part  64 . The light guiding pillar  62  is, but not limited to, a cylinder. The light guiding pillar  62  has a top surface  620  and a bottom surface  622  opposite to the top surface  620 . The bottom surface  622  is a plane and has a recess  624 . The recess  624  disposed on the central of the bottom surface  622  is concave toward the top surface  620  and an opening of the recess  624  is, but not limited to, of circular shape. In this embodiment, the top surface  620  is a plane and is substantially parallel to the bottom surface  622 . In the practical application, the top surface  620  can be a convex face to enhance the uniformity of the light passed through or a concave face to converge the light passed through. 
     The extending part  64  having a plurality of light guide strips  642  is connected to the light guiding pillar  62  and extended from the circumference of the top surface  620 . A light-emitting surface  640  are disposed on the end of the light guide strips  642 . An included angle θ is formed between the light-emitting surface  640  and the bottom surface  622 . In this embodiment, the included angle θ is an obtuse angle, which is larger than ninety degrees. In the practical application, the included angle θ can be a right angle or an acute angle for adjusting the light-emitting angle. The LED  90  is disposed on the recess  624  and emits light to the optical element  60 . 
     To sum up, in the present invention, the optical element uses the extending part which is extended from the circumference of the top surface to guide the light entered the optical element so that the light can be refracted by the extending part or reflected to the light-emitting surface and emitting from the light-emitting surface to enlarge the light-emitting angle of light passed through the optical element. Moreover, charging an included angle formed between the light-emitting surface and the bottom surface can provide different forms of luminous intensity distribution such that the optical element can apply in different lighting field. 
     Although the present invention has been described with reference to the foregoing preferred embodiment, it will be understood that the invention is not limited to the details thereof. Various equivalent variations and modifications can still occur to those skilled in this art in view of the teachings of the present invention. Thus, all such variations and equivalent modifications are also embraced within the scope of the invention as defined in the appended claims.