Abstract:
A light emitting diode (LED) light source structure comprises a base, and there is a notch extending from a surface to the inside of the base. At least one LED disposed in the notch is used to be a light source, and a conductive wire for providing the power is also disposed in the notch and connected with the LED. The top of the notch is covered by a diffusing layer for uniformly diffusing the light radiated from the LED.

Description:
RELATED APPLICATIONS  
       [0001]     The present application is based on, and claims priority from, Taiwan Application Serial Number 93141804, filed Dec. 31, 2004, the disclosure of which is hereby incorporated by reference herein in its entirety.  
       BACKGROUND  
       [0002]     1. Field of Invention  
         [0003]     The present invention relates to a light source structure. More particularly, the present invention relates to a light source structure for the light emitting diode (LED).  
         [0004]     2. Description of Related Art  
         [0005]     Lamplight applications are ubiquitous in industry, such as in vehicle lighting, television and computer screen displays, and indicator lights of industrial instruments. Different light source techniques are depended upon to provide different kinds of light for satisfying different application requirements.  
         [0006]     Traditionally, light bulbs have been the most general light source. Many light bulb and fluorescent tube defects have gradually become apparent when miniaturizing and varying them for lamp and lantern applications. For example, the light bulbs and fluorescent tubes on a large-sized or high-brightness apparatus consumes considerable power and generate much heat, and the light bulbs and fluorescent tubes which are able to provide high brightness usually contain hazardous environmental pollutants, such as mercury.  
         [0007]     Moreover, light bulbs and fluorescent tubes have other drawbacks of having large volume, being fragile and having low color variation for miniature apparatuses, especially portable devices. Additionally, light bulbs and fluorescent tubes are usually made of glass, making them easily damaged by violent shaking and impacts. Furthermore, the color of the light radiated from the light bulbs and fluorescent tubes cannot be substantially varied.  
         [0008]     Many of these drawbacks are overcome by the light emitting diode (LED); the LED has a more variable volume, a lower power consumption (a lower driving current), a lower heat generation and many available colors (wavelength) of light that can be chosen. Thus, the LED has become increasingly more popular in vehicle lantern applications. However, the luminous intensity of the LED is lower than the light bulb and the fluorescent tube under the same power consumption; therefore, how to effectively make good use of the light radiated from the LED is very important.  
         [0009]      FIG. 1  shows a conventional LED lantern structure. The lantern comprises two light source structures  102 , each of which comprises an LED  104 , two power conductors  106 , a condensing lens  108  and a radiating cover  110 . The LED  104  acts as the light source of the lantern. The condensing lens  108  is used to gather the light dispersed from the LED  104  and focus a light  112  toward the top of the figure. The power conductors are used to provide the power needed by the LED  104 . The radiating cover  110  is used to protect the LED  104 .  
         [0010]     The foregoing lantern structure still has some problems. First, the heat generated by the LED  104  cannot be dissipated easily since the radiating cover  110  material is resin with a low heat conductivity. Therefore, the radiating rate in the radiating cover  110  is very slow, indirectly causing the life span of the LED  104  to be shortened. Second, it is impossible to dispose many LEDs in the light source  102  due to the aforementioned problem of radiating, so the utilization of space in the radiating cover  110  cannot be improved. Thus, it is impossible to form many LEDs with different colors in the radiating cover  110  for color mixing. Third, the scope of light irradiation depends on the angle of the condensing lens  108  and cannot be further adjusted. Fourth, the fabrication cost is high since every LED  104  needs a radiating cover  110 .  
         [0011]     According to the foregoing shortcomings, a more economical and more efficient LED light structure is needed.  
       SUMMARY  
       [0012]     It is therefore an objective of the present invention to provide an LED light source structure with a higher radiating rate.  
         [0013]     It is another objective of the present invention to provide an LED light source structure with a higher utilization of space.  
         [0014]     It is still another objective of the present invention to provide an LED light source structure with a higher brightness.  
         [0015]     It is another objective of the present invention to provide an LED light source structure with a higher flexibility of optical design.  
         [0016]     It is still another objective of the present invention to provide an LED light source structure with a lower fabricating cost.  
         [0017]     It is another objective of the present invention to provide an LED light source structure with a smaller volume.  
         [0018]     In accordance with the foregoing and other objectives of the present invention, the light source structure comprises a base with a notch, wherein there are at least one LED and one conductive wire used to provide power for the LED. The color of the LEDs disposed in the notch may all be the same or all different. Finally, there is a diffusing layer over the top of the notch for uniformly diffusing the light, wherein the interface between the diffusing layer and the space in the notch can be designed as a plane surface or a curved surface for generating different diffusing patterns. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]     These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:  
         [0020]      FIG. 1  illustrates a conventional LED light source structure;  
         [0021]      FIG. 2  illustrates a cross-sectional view of the LED light source structure in accordance with an embodiment of the present invention;  
         [0022]      FIG. 3  illustrates a cross-sectional view of the LED light source structure in accordance with another embodiment of the present invention; and  
         [0023]      FIG. 4  illustrates a top view of the LED light source structure in accordance with an embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]     Reference will now be made in detail to the present preferred 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.  
         [0025]     The basic concept of the present invention is to directly dispose the LED of a light source structure on a base with a better radiating ability such that the light source structure volume is able to contain more LEDs with the same or different colors. Thus, the design of the light source structure is made more flexible, and the volume of the light source structure can be reduced.  
         [0026]      FIG. 2  shows three kinds of the light source according to an embodiment of the present invention. Light source structures  202 ,  204  and  206  all comprise a base  208 , an LED  210 , a notch  212  and a diffusing layer  214 . In general, the material of the base  208  has a bearing capacity that allows for conductive wire to be formed on it, such as provided by aluminum, ceramic or printed circuit board (PCB). There is at least one notch  212  extending from a surface of the base  208  into the inside of the base  208 . The shape of the notch  212  may be a circular form, a square form or any irregular form, and is not limited by the embodiment. The base  208  and the notch  212  may be formed as one piece.  
         [0027]     The LED  210  with any color may be mounted on the surface of the notch  212  by any mounting technique. The conductive wire (not shown in the figure) is also formed on the surface of the notch  212  by any wiring technique to provide power to the LED  210 .  
         [0028]     There is a diffusing layer  214  over the base  208  and the notch  212  such that the light emitted outwardly from the LED  210  passes through the diffusing layer  214  first. The purpose of the diffusing layer  214  is to diffuse the light emitted from the LED  210  from a dot to an area for broadening the irradiating scope. In this embodiment, the diffusing layer  214  may be a diffusing film used in a liquid crystal display (LCD) panel and made of a material such as resin.  
         [0029]     The most obvious distinction among the light source structures  202 ,  204  and  206  is the interface between the notch  212  and the diffusing layer  214 . It can be seen from  FIG. 2  that there are three interfaces  216 ,  218  and  220  between the notch  212  of the light source structures  202 ,  204  and  206  and the diffusing layer  214 , respectively. The interface  216  is concave, the interface  218  is flat and the interface  220  is convex. Different light source effects can be achieved by the different interface patterns. When light emitted from the LED  210  passes through the concave interface  216 , the light is diffused, producing a light source with a larger scope. When light emitted from the LED  210  passes through the flat interface  218 , the light is straightly emitted, producing a light source with a normal scope. When light emitted from the LED  210  passes through the convex interface  220 , the light converges, producing a light source with a smaller scope. Thus, the shape and tortuosity of the interface between the notch and diffusing layer can be determined according to the practical requirements.  
         [0030]     Furthermore, light propagating media may be filled into the notch  212  to obtain more variations of optical diffusion or convergence by varying the refracting effect of the interface between the notch  212  and diffusing layer  214 . The medium filled into the notch  212  may be any solid, liquid or gaseous material that allows passage of light. Phosphors may also be filled into the notch  212  for varying the color of the light emitted from the LED  210 .  
         [0031]      FIG. 3  illustrates another embodiment of the present invention, which describes three LED light source structures  302 ,  304  and  306 . The light source structures  302 ,  304  and  306  are similar to the light source structures  202 ,  204  and  206 , except that the number of LEDs in the notch is increased from one to a plurality of LEDs  308 ,  310  and  312 . The color of the LEDs  308 ,  310  and  312  may be the same for enhancing the brightness, or may be different, such as when the colors of the LEDs  308 ,  310  and  312  are red, blue and green, respectively, for generating multiple colors by color mixing. The operation of color mixing may be carried out by a color controller.  
         [0032]     Certainly, if there are several LEDs disposed in the notch, some of the LEDs can have one color and the rest can have another color. Because the plurality of LEDs is disposed in the same notch and not enclosed by the radiating covers separately, the spatial density of the LEDs and the luminous intensity in a unit area can be substantially enhanced.  
         [0033]      FIG. 4  is a top view of some embodiments according to the present invention. A base  402  bears light source structures  406 ,  408 ,  410  and  412 , and a diffusing layer  404  is used to cover these light source structures. The number of light source structures formed on a base is not limited by the embodiment in practice, but depends on the requirements and fabricating techniques.  
         [0034]     The forms of the light source structures  406 ,  408 ,  410  and  412  are various and flexible in design. Both the light source structures  406  and  408  have only one LED, but the notch of the light source structure  406  is a circular form and the notch of the light source structure  408  is a star form, so the light source structures  406  and  408  are able to provide different visual effects. The forms of the light source structures  410  and  412  are identical to the light source structures  406  and  408  respectively, except that the light source structures  410  and  412  comprise many LEDs with the same or different colors, so they are able to provide more brightness and more color variation. The forms of the light source structures described herein are not limited in practice; more optical variations may be obtained by the aforementioned methods, such as filling media into the notch and varying the tortuosity of the interface between the notch and diffusing layer.  
         [0035]     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.