Patent Publication Number: US-2011063608-A1

Title: Sensing Module for Light-Emitting Devices and Testing Apparatus Using the Same

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present disclosure relates to a sensing module for light-emitting devices and testing apparatus using the same, and more particularly, to a testing apparatus with a design for a removable sensing module configured to guide lights emitted from the light-emitting device in the oven to the outside of the oven without affecting the high temperature environment within the testing apparatus. 
     2. Background 
     Light emitting diodes (LED) are well known in the art. Testing of LEDs involves measurement of the light intensity emitted by the LED devices at a predefined wavelength spectrum. To ensure accurate comparative testing of the LED devices, the light emitted by the devices must be collected at a precise, reproducible manner, e.g., at a predefined distance or angle, and delivered to a light detector using appropriate optics. 
     Due to the high volume of required reliability data which is usually collected over a long period of time, these devices are diced and packaged into individual packages and tested in high temperature conditions in a testing apparatus. The next level of quality assurance is to ensure that all infant failures are eliminated through a burn-in test before shipping to customers. The LEDs formed on the wafer are cut so as to separate the dies. Each die is then assembled into a light-emitting package with bond wires connecting the bond pads of the die with the pins of the package. Once the die is assembled in a package it undergoes a burn-in test to ensure the quality and reliability of the light-emitting devices. It is absolutely necessary to conduct the burn-in test, which is a screening test conducted at high temperatures in a testing apparatus in order to eliminate early failures before shipment. 
     US 2008/0297771 discloses a high-speed optical sensing device including an optical detector, a lens set, and a splitter. The optical detector is utilized for detecting luminous intensity, the lens set is utilized for concentrating light beams toward a color analyzer, and the splitter is aligned to the illuminating device to be tested and is utilized to separate the light beam generated by the illuminating device to the optical detector and the lens set simultaneously. 
     SUMMARY 
     One aspect of the present disclosure provides a testing apparatus with a design for a removable sensing module configured to guide lights emitted from the light-emitting device in the oven to the outside of the oven without affecting the high temperature environment within the testing apparatus. 
     A sensing module for light-emitting devices according to this aspect of the present disclosure comprises a substrate having at least one first hole and at least one second hole connected to the first hole; an optical device positioned between the first hole and a light-emitting device, the optical device being configured to collect emitting lights from the light-emitting device to the first hole; a light-guiding device positioned in the second hole; a reflector positioned in the first hole and configured to reflect the emitting lights from the light-emitting device to the light-guiding device; and an optical coupler positioned at a front end of the substrate and coupled with the light-guiding device. 
     A testing apparatus for light-emitting devices according to another aspect of the present disclosure comprises an oven including a front wall having at least one front opening; a carrier module configured to load at least one light-emitting device into the oven through the front opening in a removable manner; and a sensing module configured to guide lights emitted from the light-emitting device in the oven to the outside of the oven. In one embodiment of the present disclosure, the sensing module comprises a substrate having at least one first hole and at least one second hole connected to the first hole; an optical device positioned between the first hole and a light-emitting device, the optical device being configured to collect lights from the light-emitting device to the first hole; a light-guiding device positioned in the second hole; a reflector positioned in the first hole and configured to reflect the lights from the light-emitting device to the light-guiding device; and an optical coupler positioned at a front end of the substrate and coupled with the light-guiding device. In one embodiment of the present disclosure, the sensing module is configured to load the light-guiding device and the reflector into the oven through the front opening in a removable manner so as to form an optical path to guide lights emitted from the light-emitting device in the oven to the outside of the oven. 
     The removable design of the sensing module allows operators not to place the optical path consisting of the optical lenses and the light-guiding device in the testing environment at high temperature and/or high humidity so as to prevents the optical path from being degraded under the high temperature and/or high humidity in the oven over long stress time. In addition, due to the optical path design, the testing apparatus of the present disclosure allows the operator to guide lights emitted from the light-emitting device in the oven to the outside of the oven without affecting the high temperature environment within the testing apparatus. 
     The foregoing has outlined rather broadly the features and technical advantages of the present disclosure in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter, and form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objectives and advantages of the present disclosure are illustrated by the following description and upon reference to the accompanying drawings in which: 
         FIG. 1  and  FIG. 2  illustrate a testing apparatus for light-emitting devices according to one embodiment of the present disclosure; 
         FIG. 3  illustrates a carrier module according to one embodiment of the present disclosure; 
         FIG. 4  and  FIG. 5  illustrate a sensing module according to one embodiment of the present disclosure; 
         FIG. 6  illustrates a sensing module according to another embodiment of the present disclosure; and 
         FIG. 7  illustrates a sensing module according to another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  and  FIG. 2  illustrate a testing apparatus  10  for light-emitting devices  123  according to one embodiment of the present disclosure. Referring to  FIG. 1 , the testing apparatus  10  comprises an oven  11  including a front wall  13  having at least one front opening  15 , a carrier module  100  configured to load light-emitting devices  123  (shown in  FIG. 3 ) into the oven  11  through the front opening  15  in a removable manner, and a sensing module  200  configured to guide lights emitted from the light-emitting device  123  inside the oven  11  to the outside of the oven  11 . 
     Referring to  FIG. 2 , in one embodiment of the present disclosure, the front wall  13  has a plurality of front openings  15 A each with a self-closing door  17  to isolate the internal testing environment of the testing apparatus  10  from the surrounding environment. Consequently, the testing apparatus  10  allows the carrier module  100  and the sensing module  200  to be inserted into and removed from the oven  11  through the front openings  15 A of the front wall  13 ; in other words, the testing apparatus  10  of the present disclosure allows the operator to load the optical sensor  240  and the light-emitting device  123  into the testing oven  11  without affecting the high temperature environment within the testing apparatus  10 . In one embodiment of the present disclosure, the optical sensor  240  can be the photo detector or the spectrum analyzer. 
       FIG. 3  illustrates a carrier module  100  according to one embodiment of the present disclosure. In one embodiment of the present disclosure, the carrier module  100  includes a frame  110 , a circuit board  120  positioned on one side of the frame  110  and having a plurality of holes  121  with the light-emitting devices  123  under test positioned inside the holes  121 , and a front plate  130  with an electrical connector  131 . In one embodiment of the present disclosure, the electrical connector  131  is electrically connected to a tester (not shown in the drawings), which controls the testing process, including setting parameters such as the applied current to the light-emitting devices  123  during the testing process. 
       FIG. 4  and  FIG. 5  illustrate a sensing module  200  according to one embodiment of the present disclosure. In one embodiment of the present disclosure, the sensing module  200  comprises a substrate  210  having at least one first hole  211  and at least one second hole  213  connected to the first hole  211 , a light-guiding device  223  such as the optical fiber or optical waveguide positioned in the second hole  221 , a reflector  221  positioned in the first hole  211  and configured to reflect the emitting lights from the light-emitting device  123  to the light-guiding device  223 , and an optical coupler  253  positioned at a front end of the substrate  210  and coupled with the light-guiding device  223 . In one embodiment of the present disclosure, the sensing module  200  is configured to load the light-guiding device  223  and the reflector  221  into the oven  11  through the front opening  15  in a removable manner so as to form an optical path to guide lights emitted from the light-emitting device  123  in the oven  11  to the outside of the oven  11 . 
     In one embodiment of the present disclosure, the first hole  211  and the second hole  213  are positioned in the substrate  210  in a substantially perpendicular manner. In one embodiment of the present disclosure, the sensing module  200  further comprises a front plate  250  positioned at the front end of the substrate  210 , and a grip member  251  positioned on the front plate  250 . In one embodiment of the present disclosure, the front plate  250  includes a plurality of optical couplers  253  each coupled with one of the light-guiding devices  223  in the second hole  213 . 
     During the testing of the light-emitting device  123  under test, the sensing module  200  is inserted into the oven  11  through the front opening  15  such that the light-emitting device  123  on the carrier module  100  faces a respective reflector  221  in the first hole  211  on the sensing module  200 , and the optical coupler  253  is coupled with the optical sensor  240 , which sensing the emitting lights of the light-emitting device  123  under test to determine whether the light-emitting device  123  under test complies with the predetermined specification. Once the sensing is completed, the sensing module  200  is preferably removed from the front opening  15  to the outside of the oven  11 , rather than remaining in the testing environment while the sensing is not performed. 
       FIG. 6  illustrates a sensing module  200 ′ according to another embodiment of the present disclosure. In one embodiment of the present disclosure, the sensing module  200 ′ further comprises an optical device  225  positioned between the first hole  211  and a respective light-emitting device  123  under test, and the optical device  225  is an optical lens such as a condenser configured to collect emitting lights from the light-emitting device  123  to the light-guiding device  223  in the first hole  211 . 
       FIG. 7  illustrates a sensing module  200 ″ according to another embodiment of the present disclosure. In one embodiment of the present disclosure, the sensing module  200 ″ further comprises an optical device  225  positioned in the first hole  211  and facing a respective light-emitting device  123  under test, and the optical device  225  is an optical lens such as a condenser configured to collect emitting lights from the light-emitting device  123  to the light-guiding device  223  in the first hole  211 . 
     In particular, the removable design of the sensing module allows operators not to place the optical path consisting of the optical lenses and the light-guiding device in the testing environment at high temperature and/or high humidity so as to prevents the optical path from being degraded under the high temperature and/or high humidity in the oven over long stress time. This helps prevent damage to the optical path, and the damage of the light-guiding device obviously affects the accuracy of the optical test data. In addition, due to the optical path design, the testing apparatus of the present disclosure allows the operator to guide lights emitted from the light-emitting device in the oven to the outside of the oven without affecting the high temperature environment within the testing apparatus. 
     Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. For example, many of the processes discussed above can be implemented in different methodologies and replaced by other processes, or a combination thereof. 
     Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.