The present disclosure is generally directed toward light emitting devices and packages for the same.
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.
Two prevalent types of LED form factors are surface-mount LEDs and thru-hole LEDs. Surface-mount LEDs are desirable for applications which require a low LED profile. Among the various packages for surface-mount LEDs, an LED package of interest is the Plastic Leaded Chip Carrier (PLCC) package. Surface mount LEDs in PLCC packages may be used, for example, in automotive interior display devices, electronic signs and signals, and electrical equipment.
In both surface-mount LEDs and thru-hole LEDs, lenses have been used to achieve a desired radiation pattern with a controlled viewing angle. To date, the lens profiles have been rounded across both their x-axis and y-axis. These types of lenses have been referred to as dual-axial lenses. Some lens profiles have been constructed to be dual-axis symmetrical (e.g., round shape) or dual-axis non-symmetrical (e.g., oval shape). There are several disadvantages to shaping lenses in such a way.
One problem with dual-axial lenses is that they are centrically aligned with respect to a single point. This means that dual-axial lenses can optimally shape light from a single light source. This also means that any misalignment of the single light source will result in the output light being sub-optimal.
Another problem with dual-axial lenses is that they are relatively difficult to fabricate in a repeatable and optimal manner. As with the misalignment problem described above, because a dual-axial lens is only optimally manufactured for a single point, there is less tolerance to lens fabrication errors. In other words, any lens fabrication errors in either the x-axis or the y-axis will result in a sub-optimal light output.
The present disclosure is described in conjunction with the appended figures:
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.
With reference now to
The light sources 132a, 132b, 132c may correspond to any type of known light-emitting device. In some embodiments, the light sources 132a, 132b, 132c may correspond to a Light Emitting Diode (LED), a collection of LEDs, a laser diode, a collection of laser diodes, or any other solid-state light-emitting device. As a non-limiting example, the light sources 132a, 132b, 132c may be configured to emit light of the same characteristics (e.g., color, wavelength, frequency, etc.) or light of different characteristics. For instance, the light sources 132a, 132b, 132c may correspond to red, green, and blue light-emitting LEDs.
The illustrative mono-axial lens 100 comprises a first end 104 and second end 108 with a middle section 112 provided therebetween. The mono-axial lens 100 further includes a single rounded axial plane 116 (e.g., a plane defined between the x-axis and z-axis). The profile of the rounded axial plane 116 is depicted as including a top curved portion 120 and a bottom portion 124. The bottom portion 124 may be substantially flat or planar whereas the curved portion 120 may be rounded (e.g., with a radius of curvature R) substantially within the rounded axial plane 116.
The mono-optical lens 100 is configured to house the light sources 132a, 132b, 132c and create substantially symmetrical radiation patterns for each of the light sources 132a, 132b, 132c. This feature of symmetrically radiating light from each source 132a, 132b, 132c can be achieved by aligning each of the light sources 132a, 132b, 132c along a common axis 128. In some embodiments, the common axis 128 corresponds to a longitudinal axis of the mono-axial lens 100 and the common axis 128 passes directly through the middle of the mono-axial lens 100.
In the coordinate system depicted in
In some embodiments, the radius R of the curved portion 120 may be any suitable dimension. Specifically, depending upon the relative size of the mono-axial lens 100 and the light sources 132a, 132b, 132c, the radius R may vary from as small as a micrometer to as large as a meter or more. In other words, the actual size of the radius R can be selected from any suitable size depending upon the desired lighting conditions and radiation pattern.
Furthermore, while
With reference now to
In some embodiments, the lighting package includes a leadframe 404 that is substantially configured for thru-hole mounting to a Printed Circuit Board (PCB) or the like. Specifically, the leadframe 404 is constructed from a flat or planar piece of metal and the leadframe 404 is shown to include a plurality of leads 408a, 408b, 408c that extend downwardly from the mono-axial lens 100. In the depicted embodiment, the first lead 408a and third lead 408c are used for a second electrical connection to the light sources 132a, 132b, respectively, whereas the second lead 408b comprises the reflector cups 412a, 412b and supports the light sources 132a, 132b. In some embodiments, the second lead 408b may be configured for connection to an electrical ground or common voltage and the first and third leads 408a, 408c may be used to carry electrical current that dictates whether the light source 132a, 132b is turned on or off. In some embodiments, the material of the mono-axial lens 100 extends below the reflector cups and completely encapsulates the light sources 132a, 132b within the reflector cups.
As can be seen in
With reference now to
The second lighting package comprises a leadframe 504 with a plurality of leads 508a-f configured for surface mounting to a PCB or the like. Although the leads 508a-f are depicted as being configured with an L-bend, it should be appreciated that any type of lead shape may be utilized. Examples of suitable leads shapes include, without limitation, J-wings, C-bends, gullwings, reverse gullwings, etc.
Again, each of the light sources 132a, 132b, 132c are aligned along a common axis 128 that extends through the middle of the mono-axial lens 100. Thus, each reflector cup 512a, 512b, 512c may be centered on the common axis 128, even though the reflector cups 512a, 512b, 512c are attached to different leads 508d, 508b, 508f, respectively. As with the first lighting package, the second lighting package may comprise a mono-axial lens that extends below the reflector cups and encapsulates the reflector cups and light sources. Also as with the first lighting package, a greater or lesser number of light sources may be included in the lighting package without departing from the scope of the present disclosure.
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. For example, circuits may be shown in block diagrams in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments.
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.