Abstract:
A package for a light source and methods of manufacturing the same are disclosed. In particular, a light source package is disclosed with an outer component and an interchangeable inner component. The inner component can be modular and replaceable with other inner components having different properties, thereby enabling a flexible design of a light source package to accommodate different lighting conditions and desired lighting effects.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    The present disclosure is generally directed toward light emitting devices and packages for the same. 
       BACKGROUND 
       [0002]    Light Emitting Diodes (LEDs) have many advantages over conventional light sources, such as incandescent, halogen and fluorescent lamps. These advantages include longer operating life, lower power consumption, and smaller size. Consequently, conventional light sources are increasingly being replaced with LEDs in traditional lighting applications. As an example, LEDs are currently being used in flashlights, camera flashes, traffic signal lights, automotive taillights and display devices. 
         [0003]    Currently light source packages utilize a latch-on-lens to produce the desired radiation pattern with a controlled viewing angle. Other design concepts utilize an integrated reflector cup and the dimensions of the reflective cup must be altered to achieve the desired light output. 
         [0004]    One disadvantage to the latch-on-lens concept is that it introduces an additional element to the finished product, thereby adding bulk and cost. There is also a strict tolerance control for the lens profile. And, perhaps most importantly, the aesthetics of a latch-on-lens are generally considered less desirable than light source packages having an integrated lens. 
         [0005]    The integrated reflector cup also has drawbacks. In particular, a light source package with an integrated reflector cup has limited design freedom and the physical dimensions of the entire package are often constrained by the selected reflector cup. Additionally, the package becomes more costly and is of substantially no use to those that do not need a reflector cup. 
       SUMMARY 
       [0006]    It is with respect to the above-noted shortcomings that embodiments of the present disclosure were developed. Specifically, embodiments of the present disclosure provide a light source package with an interchangeable inner component that greatly enhances the design opportunities for the light source package. The light source package disclosed herein is less bulky than the latch-on-lens packages and is less costly than packages having an integrated reflector cup. 
         [0007]    One advantage of the present disclosure is that the light source package can be individually optimized for any use-case. In other words, the design flexibility offered by embodiments of the present disclosure is greatly increased. In particular, the hybrid nature of the disclosed light source package can accommodate the various viewing angle requirements for any environment. 
         [0008]    In some embodiments, the light source package includes a hybrid reflector cup cum lenses concept. The approach is to introduce an inner component, which has had the flexibility of changing its refractive index. In some embodiments, the creation and customization of the inner component can be achieved through injection molding of epoxy and/or silicone. The inner component can then be ‘laminated’ by an outer component. This outer component, in some embodiments, can be of black or white polymer, such as Polyphthalamide (PPA), or a similar thermoplastic synthetic resin of the polyamide family. This outer component, in addition to providing structural protection to the inner component and other parts of the light source package, can function to block light rays from penetrating or passing through. The outer component can also be designed to enhance the contrast when a black or dark material is used. 
         [0009]    In some embodiments, the light source package may also be designed to provide an air gap between the inner component and the outer component. In some embodiments, the air gap between the inner and outer components can act as a ‘mirror’ wall to the rays emitted by the light source. This reflection by the air gap occurs because when light passes from a material of a high refractive index (e.g., inner component, n&gt;1) to a material of a lower index (e.g., air, n=1), then internal refraction will occur. This design proposed herein greatly improves the reflector cup&#39;s reflectivity compared to prior art designs which only diffuse the light instead of reflecting the light. Of particular note is that the average viewing angle of the light source package can also be narrowed (e.g., controlled) by providing an air gap between the inner component and the outer component. Table 1 below shows the viewing angle differences between a light source package designed in accordance with embodiments of the present disclosure as compared to traditional packages: 
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Air Gap vs. Non-Air-Gap Viewing Angle Differences 
               
               
                 Average Viewing Angle 
               
             
          
           
               
                   
                   
                 Air 
                 Non Air 
               
               
                   
                   
                 gap 
                 gap 
               
               
                   
               
               
                   
                 Blue 
                 90.3 
                 107.6 
               
               
                   
                 Green 
                 97.9 
                 111.8 
               
               
                   
                 Red 
                 98.8 
                 110.2 
               
               
                   
               
             
          
         
       
     
         [0010]    In addition to the introduction of an air gap, embodiments of the present disclosure also provide an inner component that is interchangeable with other inner components, thereby further increasing the design freedom offered by the light source package. Interchangeable inner components enable the light source package to have different inner components with different refractive indices (RI). By having the changeable RI feature, the inner component can be selected to best compliment the type of light that is being emitted by the light source (e.g., different wavelengths of light may interact optimally with different inner components). For example, if the emitting light source&#39;s lambda is approximately 450 nm, the suitable inner component candidate to be chosen to have a RI of approximately 1.575. 
         [0011]    Another aspect of the present disclosure is to provide at least some of the interchangeable inner components with one or more light-shaping elements. Examples of suitable light-shaping elements that can be incorporated into the inner component include, without limitation, Fresnel rings, dome shapes, cavity shapes, textured roughening, etc. 
         [0012]    The present disclosure will be further understood from the drawings and the following detailed description. Although this description sets forth specific details, it is understood that certain embodiments of the invention may be practiced without these specific details. It is also understood that in some instances, well-known circuits, components and techniques have not been shown in detail in order to avoid obscuring the understanding of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The present disclosure is described in conjunction with the appended figures: 
           [0014]      FIG. 1  is an isometric view of a light source package in accordance with embodiments of the present disclosure; 
           [0015]      FIG. 2  is a cross-sectional isometric view of a light source package in accordance with embodiments of the present disclosure; 
           [0016]      FIG. 3  is an isometric view of a first internal package component in accordance with embodiments of the present disclosure; 
           [0017]      FIG. 4  is an isometric view of a second internal package component in accordance with embodiments of the present disclosure; 
           [0018]      FIG. 5  is a cross-sectional view of a third internal package component inserted into an outer package component in accordance with embodiments of the present disclosure; 
           [0019]      FIG. 6  is a cross-sectional view of a fourth internal package component inserted into an outer package component in accordance with embodiments of the present disclosure; and 
           [0020]      FIG. 7  is a flow diagram depicting a method of manufacturing and using a light source package in accordance with embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    The ensuing description provides embodiments only, and is not intended to limit the scope, applicability, or configuration of the claims. Rather, the ensuing description will provide those skilled in the art with an enabling description for implementing the described embodiments. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the appended claims. 
         [0022]    As can be seen in  FIGS. 1-6 , a package for a light source and various component parts of the same are depicted. As will be described herein, although a particular configuration of package is depicted and described, those of ordinary skill in the art will appreciate that embodiments of the present disclosure are not limited to any particular type of package configuration. In particular, principles discussed herein may be applied in various combinations. Accordingly, although a light source package having a particular configuration is described herein, it should be appreciated that embodiments of the present disclosure are not so limited. 
         [0023]      FIG. 1  depicts a light source package  100  in accordance with at least some embodiments of the present disclosure. The light source package  100  is shown to include an outer component  104  and an inner component  108 . As will be discussed in further detail herein, the inner component  108  may be interchangeable with other inner components  108  that have similar or different light-shaping properties, refractive indices, or combinations thereof. 
         [0024]    In some embodiments, the outer component  104  and/or inner component  108  can be manufactured with injection molding techniques. Specifically, the outer component  104  may be constructed of any polymer or combination of polymers using extrusion, machining, micro-machining, molding, injection molding, or a combination of such manufacturing techniques. As a non-limiting example, the inner component  104  may comprise PPA (black or white), other polymers, ceramics, metal alloys, or combinations thereof. 
         [0025]    The inner component  108  may be manufactured of epoxy, silicone, a hybrid of silicone and epoxy, phosphor, a hybrid of phosphor and silicone, an amorphous polyamide resin or fluorocarbon, glass, plastic, or combinations thereof. As with the outer component  104 , the inner component  108  may be constructed using any known technique such as extrusion, machining, micro-machining, molding, injection molding, or a combination thereof. In some embodiments, the material used for the inner component  108  may be matched specifically to the light that is emitted by the light source package  100 . For instance, the material used for the inner component  108  may be selected based, at least in part, on the wavelength of light emitted by a light source contained in the light source package. 
         [0026]    With reference now to  FIG. 2 , additional details of a light source package  100  will be described in accordance with embodiments of the present disclosure. The outer component  104  is depicted as having a plurality of sidewalls  204  attached to a base  212 . In some embodiments, the sidewalls  204  are integrally attached to the base  212  because all parts of the outer component  104  are molded from a single piece of material. Each sidewall  204  may comprise an inner face  208  that faces toward and establishes an inner cavity of the outer component  104 . The inner cavity established by the sidewalls  204  and base  212  may be open at its top as light is configured to exit via the opening at the top of the outer component  104 . The base  212  may comprise a top surface  216  that is configured to support one or more light sources and/or other electronics. The top surface  216  may also be configured to interface with at least a portion of the inner component  108 . As an example, the top surface  216  of the base  212  may provide a structural support for the inner component  108  and/or an interconnection mechanism that enables the inner component  108  to be removably interconnected to the outer component  104 . 
         [0027]    The inner component  108 , in some embodiments, may be conically shaped, thereby enabling the inner component  108  to acts as a reflector cup. The inner component  108  may comprise an inner face  220  and an outer face  224 . The inner face  220  of the inner component  108  may also be referred to as the reflective face of the inner component  104  as it corresponds to the first surface that receives light emitted by a light source mounted within the inner component  108 . The outer face  224  may be proximate to and face toward the inner face  208  of the sidewalls  204 . In some embodiments, a gap  228  is established between the outer face  224  of the inner component  108  and the inner face  208  of the sidewalls  204 . 
         [0028]    The gap  228  provides a number of advantages and functions. As some examples, the gap  228  may comprise a material or gas therein (e.g., air) with a refractive index that is lower than the refractive index of the material used to construct the inner component  108 . By providing the difference in refractive indices at the boundary between the gap  228  and inner component  108 , light that is traveling through the material of the inner component  108  to the outer face  224  will be reflected at the boundary. Therefore, most or all of the light that was not reflected by the inner face  220  of the inner component  108  will be reflected by the outer face  224  of the inner component  108 . The gap  228  also enables the inner component  108  to interface with the outer component  104  without requiring both components to be built with strict machining tolerances. In other words, the gap  228  enables both components to be built with less restrictive machining tolerances and still interface with one another. 
         [0029]    Although most embodiments described herein will refer to the gap  228  being filled with a gas, such as air, it should be appreciated that embodiments of the present disclosure are not so limited. In particular, the gap  228  may be filled with any material that has a lower refractive index that the material of the inner component  108 . The material which fills the gap  228  may be solid, liquid, semi-solid, or gas. 
         [0030]    It should be appreciated that the inner component  108  may be formed in any uniform or non-uniform shape (e.g., circular, elliptical, trapezoidal, square, rectangular, triangular, etc.) depending upon the desired light distribution. In some embodiments, the area of the inner component  108  is larger its top surface as compared to its bottom surface. This means that the inner component  108  gets larger as it extends away from the base  212 . 
         [0031]    In some embodiments, the inner face  220  of the inner component  108  is coated with a reflective material. Specifically, the inner face  220  may be coated with a reflective material such as tin, aluminum, etc. to increase the reflectivity of the inner face  220 . The reflective material may be deposited on the inner face  220  via any known deposition process such as electroplating, ALD, CVD, magnetron sputtering, and the like. 
         [0032]      FIG. 3  depicts further details of an illustrative inner component  108  in accordance with embodiments of the present disclosure. The inner component  108  may comprise a bottom portion  304  configured to enable a removable interconnection with the base  212  of the outer component  104 . Specifically, the bottom portion  304  of the inner component  108  comprises an extension  308  having one or more hooked tabs  312  with associated notches  316 . The extension  308  and hooked tabs  312  may be configured to interface with a female hole or receiving member on the base  212  of the outer component  104 . Once inserted, the inner component  108  may be rotated within the outer component  104  to engage the notch  316  with the receiving member on the base  212 . 
         [0033]    In another embodiment, rather than having hooked tabs  312  and notches  316 , the extension  308  may be threaded (female or male threading) and the base  212  may have corresponding threads. The threading of the extension  308  may interface with the threading of the base  212 , thereby enabling a friction fitting between the inner component  108  and outer component  104 . 
         [0034]      FIG. 4  depicts details of another illustrative inner component  108  in accordance with embodiments of the present disclosure. The inner component  108  depicted in  FIG. 4  comprises a straight tab  404  instead of the hooked tab  312  depicted in  FIG. 3 . The tabs  404  of the inner component  308  can interface with one or more holes or vias in the base  212  of the outer component  104 . In some embodiments, an adhesive or epoxy may be used to secure or fix the tab  404  into the base  212  of the outer component  104 . 
         [0035]      FIG. 5  depicts yet another inner component  108  configuration in accordance with embodiments of the present disclosure. The inner component  108  shown in  FIG. 5  exhibits a flange  504  that extends substantially perpendicularly to the major axis of the inner component  108 . The flange  504  may completely circumvent the bottom of the inner component  108  or the inner component  108  may have a plurality of flanges that are intermittently separated by space or notches. The flange(s)  504  of the inner component  108  may interface with the outer component  104  at one or more fittings  508 . The fittings  508  in the outer component  104  may comprise a notch or recess that receives the flange(s)  504  and secure the inner component  108  to the outer component  104 . 
         [0036]      FIG. 5  also depicts additional components that may be incorporated in a light source package  100 . Specifically, the light source package  100  is shown to include a light source  516  and encapsulant  520 . Both the light source  516  and encapsulant  520  are mounted to the top surface  216  of the base  212  within the cavity  512  defined by the inner face  220  of the inner component  108 . In some embodiments, the light source  516  may be mounted directly to the top surface  516 , one or more wire bonds may be established between a lead frame and the light source, and then some amount of encapsulant  520  may be deposited around the light source  516  and bonding wires to protect those components. In some embodiments, the cavity  512  may be further filled (partially or completely) with another encapsulant material other than encapsulant  520 . Any number of materials may be suitable for use as the encapsulant  520 . Examples of such materials include, without limitation, epoxy, silicone, a hybrid of silicone and epoxy, phosphor, a hybrid of phosphor and silicone, an amorphous polyamide resin or fluorocarbon, glass, plastic, or combinations thereof. Furthermore, the encapsulant  520  (or the other encapsulant that fills the cavity  512 ) may be formed to have one or more light-shaping elements (e.g., lens, prism, curved or non-linear feature, etc.) incorporated therein. Specifically, the encapsulant  520  can be formed to have one or more curved surfaces which shape the light emitted by the light source  516  in a desired pattern. As a non-limiting example, the light-shaping element may comprise a dome, a curved surface, a series of curved surfaces, or any other type of surface for directing light in a predetermined direction. 
         [0037]    The light source  516 , in some embodiments, comprises an LED or array of LEDs. Where an LED or similar light source is used, one bonding wire can be connected to an anode of the light source  516  whereas another bonding wire is connected to a cathode of the light source  516 . In some embodiments, the anode and cathode are both on the top light-emitting surface of the light source  516 . In some embodiments, the anode and cathode are on opposite surfaces of the light source  516 . Such a light source  516  may be constructed using known flip-chip manufacturing processes or any other known method for establishing both an anode and cathode on a common side of a light source  516 . In either configuration, by connecting the anode and cathode of the light source  516  to two different conductive leads, an electrical potential can be applied to the anode and cathode of the light source  516  thereby energizing the light source  516  and causing it to emit light. Other suitable light sources include, without limitation, a laser diode, an array of laser diodes, an array of LEDs, or a combination of laser diodes and LEDs. 
         [0038]      FIG. 5  also shows a different variation of gap  228  between the inner component  108  and outer component  104 . Specifically, the gap  228  depicted in  FIG. 5  extends from the flange  504  all the way to the top surface of the inner component  108  and outer component  104 , whereas the gap  228  depicted in  FIG. 2  does not extend all the way to the top surface of the inner component  108  and outer component  104 . Additionally, the gap  228  depicted in  FIG. 2  is shown to be larger toward the base  212  and smaller toward the top surface whereas the gap  228  depicted in  FIG. 5  is substantially uniform in width along its length. 
         [0039]      FIG. 6  depicts yet another variant of the inner component  108 . In particular, the inner component  108  may include one or more light-shaping elements  604 . The light-shaping elements  604  may correspond to any element or combination of elements that are incorporated into the inner component  108  or attached to the inner component  108  that perform some light-shaping function. Examples of light-shaping elements  604  include, without limitation, Fresnel rings, dome shapes, cavity shapes, textured roughening, etc. The light-shaping elements  604  may be disposed concentrically about the inner component  108  with uniform or non-uniform spacing. 
         [0040]    Referring now to  FIG. 7 , a method of manufacturing and using a light source package  100  will be described in accordance with at least some embodiments of the present disclosure. The method begins with the receipt of the outer component  104  (step  704 ). Thereafter, a determination is made as to which inner component  108  should be attached to the outer component  104  (step  708 ). In some embodiments, the determination of the inner component  108  may depend upon the color of light emitted by the light source  516 , the desired viewing angle, material within the gap  228 , material used for the outer component  104 , and/or other considerations. 
         [0041]    The selected inner component  108  is then inserted into the outer component  104  (step  712 ). This step may occur before or after a light source  516  is mounted to the base  212  of the outer component  104 . Furthermore, the manner in which the inner component  108  is inserted into the outer component  104  may depend upon the nature of the interface between the components  104 ,  108 . For example, some embodiments may simply rely on a friction or mechanical fit between the two components while other embodiments may utilize an adhesive or epoxy to attach the two components. Other embodiments may utilize magnets or the like to engage the inner component  108  with the outer component  104 . Additional manufacturing steps may then be performed, such as filling the cavity  512  of the inner component  108  with an encapsulant or the like. 
         [0042]    Once manufactured, the light source package  100  is ready for use. In particular, use of the light source package  100  may involve generating light at the light source  516  (step  716 ). The light generated at the light source  516  may travel away from the light-emitting surface of the light source through the encapsulant  520  surrounding the light source  520 , into the cavity  512  until it eventually reaches the inner component  108  (step  720 ). In particular, the light generated by the light source  516  is initially received at the inner face  220  of the inner component  108 . Depending upon the nature and material provided on the inner face  220 , at least some of the light incident on the inner face  220  may be reflected in a direction generally toward the opening of the cavity  512 . Still other light may pass into the material of the inner component  108 . Specifically, at least some light may be refracted at the inner face  220  when it enters the inner component  108 . 
         [0043]    The light that passes through the inner face  220  and into the inner component  108  may travel through the material of the inner component  108 , which may have an index of refraction greater than 1.00. When the light passing through the inner component  108  reaches the outer face  224  of the inner component  108 , some of the light may be reflected at the outer face  224 , because the index of refraction of the material in the gap  228  is less than the index of refraction of the material used to construct the inner component  108  (step  724 ). The light reflected at the outer face  224  may also be directed upward, in the general direction of the opening of the cavity  512 . 
         [0044]    Although it may be possible to design the inner component  108  to achieve total internal reflection at the outer face  224 , it may also be possible that some light passes through the outer face  224 . Any light that passes through the outer face  224  may travel through the gap  228  (step  728 ) until it reaches the outer component  104  where the light can either be absorbed or reflected (step  732 ). In some embodiments, the outer component  104  may be constructed of a non-reflective material, which means that light passing through the gap  228  may be absorbed by the outer component  104 . Still other embodiments contemplate that the inner face  208  of the sidewall  204  may be treated with a reflective material, further enhancing the amount of light output by the light source package  100 . 
         [0045]    Specific details were given in the description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments. 
         [0046]    While illustrative embodiments of the disclosure have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art.