Abstract:
Disclosed is an apparatus for testing an LED lamp which includes: a secured seat on which the LED lamp is seated; an up and down shifter which, when the LED lamp is seated on the secured seat, shifts from an initial position spaced upward from the LED lamp to a measurement position in which the up and down shifter contacts with a socket of the LED lamp, and which supplies electric power to the LED lamp when the up and down shifter is placed in the measurement position, and a sensor sensing that the up and down shifter is placed in the measurement position; and a quality determining means determining a quality of the LED lamp based on light emitted from the LED lamp, and comprising an illuminometer or a luminance meter.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 U.S.C. §119(e) of Korean Patent Application No. 10-2010-0025488, filed on Mar. 22, 2010, and Korean Patent Application No. 10-2010-0025490, filed in the Republic of Korea on Mar. 22, 2010, which is hereby incorporated by reference for all purposes as if fully set forth herein. 
     BACKGROUND 
     This embodiment relates to a testing apparatus and a method for testing a light emitting diode (LED) lamp. 
     In general, a light emitting diode (hereinafter, referred to as LED) is an electronic component emitting light through recombination of minority carriers (electrons) injected into a p-n junction structure of a semiconductor. 
     An LED lamp manufactured with such an LED not only has a small size and a long life span but also directly converts electric energy into light energy so that it consumes low electric power and emits light with high efficiency and high intensity. 
     The LED responds at a high speed. Therefore, the LED is used as a numeric display device and a display lamp of various electronic equipments, for example, a display device of a vehicle dashboard, a light source for optical communication, etc., and is also variously used as lighting means for homes, vehicles, ships, traffic signals, various guide lamps and refuge guide lamps and the like. 
     SUMMARY 
     One embodiment is an apparatus for testing an LED lamp. The apparatus may include: a secured seat on which the LED lamp is seated; an up and down shifter which, when the LED lamp is seated on the secured seat, shifts from an initial position spaced upward from the LED lamp to a measurement position in which the up and down shifter contacts with a socket of the LED lamp, and which supplies electric power to the LED lamp when the up and down shifter is placed in the measurement position, and which includes a sensor sensing that the up and down shifter is placed in the measurement position; and a quality determining means determining, in response to the sensor&#39;s sensing that the up and down shifter is placed in the measurement position, a quality of the LED lamp based on light emitted from the LED lamp, and including an illuminometer or an luminance meter. 
     Another embodiment is an apparatus for testing an LED lamp. The apparatus may include: an optical characteristic measuring means including an illuminometer or an luminance meter and measuring an optical characteristic value of the LED lamp; an arithmetic means converting the optical characteristic value obtained by the optical characteristic measuring means into an optical characteristic value for directly determining whether the quality of the LED lamp is good or poor; and a quality determining means determining whether the quality of the LED lamp is good or poor on the basis of the optical characteristic value converted by the arithmetic means. 
     Further another embodiment is a method for testing an LED lamp. The method includes: measuring an optical characteristic value of the LED lamp by using an optical characteristic measuring means; converting the optical characteristic value into a value for determining whether the quality of the LED lamp is good or poor by using an arithmetic means and a predetermined numerical expression for obtaining a value for determining whether the quality of the LED lamp is good or poor based on the optical characteristic value; and determining whether the value for determining whether the quality of the lamp is good or poor is within a predetermined range, and wherein if the value is within the predetermined range, it is determined that the quality of the lamp is good, and wherein if the value is not within the predetermined range, it is determined that the quality of the lamp is poor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a testing apparatus for testing an LED lamp according to an exemplary embodiment. 
         FIG. 2  is a cross sectional view of the testing apparatus for testing the LED lamp placed in an initial position in accordance with an exemplary embodiment. 
         FIG. 3  is a cross sectional view of the testing apparatus for testing the LED lamp placed in a measurement position in accordance with an exemplary embodiment. 
         FIG. 4  shows an internal configuration of the testing apparatus for testing the LED lamp of  FIG. 1 . 
         FIG. 5  is a flowchart showing a method for testing the LED lamp according to an exemplary embodiment. 
         FIG. 6  shows an example of parameter input of an optical characteristic value and an electric power characteristic value which are gathered by the testing apparatus for testing the LED lamp of an exemplary embodiment. 
         FIG. 7  is a distribution chart of a color coordinate measured by using an illuminometer of the testing apparatus of an exemplary embodiment. 
         FIG. 8  shows measurement result data obtained by using the illuminometer and a power meter of the testing apparatus of an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, an embodiment will be described with reference to the accompanying drawings. The embodiment can be variously transformed, and the scope of this embodiment is not limited to the following embodiment. The shapes and sizes of the components in the drawings may be exaggerated for clarity of the description. The components indicated by the same reference numerals in the drawing correspond to the same components. 
     It will be understood that when an element is referred to as being ‘on’ or “under” another element, it can be directly on/under the element, and one or more intervening elements may also be present. When an element is referred to as being ‘on’ or ‘under’, ‘under the element’ as well as ‘on the element’ can be included based on the element. 
       FIG. 1  is a front view of a testing apparatus for testing an LED lamp according to an exemplary embodiment. Referring to  FIG. 1 , the testing apparatus for testing an LED lamp  50  may include a secured seat  100 , an up and down shifter  300 , a controller  500 , a measurer  600  and a display unit  700 . 
     The testing apparatus may include the secured seat  100  placed on the upper surface of a first body  200  so as to test the LED lamp. The secured seat  100  may include a groove into which the LED lamp  50  is inserted. 
     Plate type vertical support members  400   a  and  400   b  may be arranged on both sides of the secured seat  100  on the upper surface of the first body  200 . A plate type horizontal support member  400   c  may be arranged on the upper surfaces of the vertical support members  400   a  and  400   b . Here, the up and down shifter  300  may penetrate the horizontal support member  400   c.    
     The LED lamp  50  may be tested through the following method. LEDs may be inserted into the groove of the secured seat  100 , and electric power may be applied to the testing apparatus by pressing a power (PW) switch. The up and down shifter  300  may be shifted from a determined initial position to a measurement position and may be stopped by pressing a down (DN) switch provided in the controller  500  of the testing apparatus, and then the quality of the LED lamp  50  can be tested through the measurer  600 . After the quality of the LED lamp  50  is tested, the display unit  700  may display whether the tested quality is good or poor. The display unit  700  may be connected to the controller  500  and the measurer  600 . Here, the measurer  600  receives measured values from both an equipment (not shown) for measuring the optical characteristic, for example, an illuminometer, etc., disposed on the inner basal surface of the first body  200  and an equipment (not shown) for measuring electric power characteristic, for example, a power meter connected to the up and down shifter  300 . It is possible to substitute the equipment for measuring the optical characteristic and the equipment for measuring electric power characteristic with a measuring apparatus. 
     After the LED lamp  50  is tested, the up and down shifter  300  may be shifted from the measurement position to the initial position and stopped by an UP switch provided in the controller  500 . The up and down shifter  300  may be shifted up and down by supplying fluid pressure or pneumatic pressure to a cylinder provided to the inside of the up and down shifter  300 . 
     In the test of the LED lamp  50 , a plurality of the LED lamps  50  can be tested. In the embodiment, four LED lamps  50  can be simultaneously tested. It is also possible to test one to three LED lamps  50  instead of simultaneously testing four LED lamps  50 . Besides, the embodiment may be changed such that various numbers of the LED lamps  50  can be tested without being limited to a specific number of the LED lamps  50 . 
       FIG. 2  is a cross sectional view of the testing apparatus for testing the LED lamp placed in an initial position in accordance with an exemplary embodiment.  FIG. 3  is a cross sectional view of the testing apparatus for testing the LED lamp placed in a measurement position in accordance with this embodiment. 
     When the testing apparatus is placed in the initial position, as shown in  FIG. 2 , the lower part of a sensor  360  of the up and down shifter  300  may be spaced from the upper part of a socket  51  of the LED lamp  50 . When the testing apparatus is placed in the measurement position, as shown in  FIG. 3 , the lower part of a sensor  360  of the up and down shifter  300  may come in contact with the upper part of a socket  51  of the LED lamp  50 . 
     When the lower part of the sensor  360  contacts with the upper part of the socket  51  of the LED lamp  50 , the sensor  360  may transfer a LED lamp  50  detection signal to the measurer  600  shown in  FIG. 1 . The measurer  600  may comprehensively measure the quality of the LED lamp  50  and displays the measurement result to the display unit  700 . That is, the up and down shifter  300  may be shifted by as much as the height adjusted by the sensor  360  and may contact with the socket  51  so that electric power is applied to the lamp. The characteristic value of light irradiated downward may be measured by the illuminometer disposed on the inner basal surface of the first body  200 . Simultaneously with this, the electric power characteristic value of the lamp may be measured by the power meter connected to the up and down shifter  300 . 
     Referring to  FIGS. 2 and 3 , the LED lamp  50  may include the socket  51 , a lamp  52  and a heat radiating part  53 . The lamp  52  may be inserted into the secured seat  100 . The LED lamp  50  may be inserted into the groove of the secured seat  100  in order to test the LED lamp  50 . 
     The plate type vertical support members  400   a  and  400   b  may be placed on both sides of the secured seat  100  on the upper surface of the first body  200 . The plate type horizontal support member  400   c  may be placed on the upper surface of the vertical support members  400   a  and  400   b.    
     The horizontal support member  400   c  may include a cylinder  320  and guide rods  310   a  and  310   c . The cylinder  320  may penetrate a hole formed in the horizontal support member  400   c  and moves up and down. The guide rods  310   a  and  310   c  may be arranged on both sides of the cylinder  320  along a longitudinal direction of the cylinder  320 . More specifically, a piston  320   a  of the cylinder  320  may be vertically reciprocated through the hole formed in the horizontal support member  400   c . The guide rods  310   a  and  310   c  can easily move in a sliding way through bearings  310   e  and  310   f  provided penetrating the horizontal support member  400   c  when the piston  320   a  of the cylinder  320  is vertically reciprocated. 
     In addition, a plate type horizontal member  310   d  may be attached to the lower surfaces of the cylinder  320  and the guide rods  310   a  and  310   c . A second body  330  may be attached to the lower surface of the horizontal member  310   d . Here, it is also possible that the second body  330  may be horizontally lengthened and attached to the lower surfaces of the cylinder  320  and the guide rods  310   a  and  310   c  instead of attaching the horizontal member  310   d  to the lower surfaces of the cylinder  320  and the guide rods  310   a  and  310   c  ( FIGS. 2 and 3  show that the horizontal member  310   d  is attached). Here, since the horizontal member  310   d  may be attached to the lower surfaces of the cylinder  320  and the guide rods  310   a  and  310   c , the cylinder  320  and the guide rods  310   a  and  310   c  may be fixed by the horizontal member  310   d  and it is unnecessary to increase the size of the second body  330 . 
     The sensor  360  may be inserted into the lower part of the second body  330 . The lower part of the sensor  360  is surrounded by an elastic member  350  such as a spring. The elastic member  350  protects the sensor  360  and provides an elastic force to the up and down shifter when the up and down shifter moves up. 
     Guides  340   a  and  340   b  may be formed on both sides of the elastic member  350 . The guides  340   a  and  340   b  may prevent the elastic member  350  from meandering. The guides  340   a  and  340   b  may allow the elastic member  350  to vertically move up and down within the inside of the guides  340   a  and  340   b.    
       FIG. 4  shows an internal configuration of the testing apparatus for testing the LED lamp of  FIG. 1 . Referring to  FIG. 4 , the apparatus for testing the LED lamp may include an optical characteristic measuring means  610 , an electric power characteristic measuring means  620 , an arithmetic means  630  and a quality determining means  640 . 
     The optical characteristic measuring means  610  may measure an optical characteristic value of the LED lamp. The electric power characteristic measuring means  620  may include, for example, a power meter. The optical characteristic value may be obtained by measuring at least one selected from among illumination, chromaticity, a color coordinate and a color temperature of the LED lamp. The optical characteristic measuring means  610  may include, for example, the illuminometer (which may be referred to as a color temperature meter). Another kind of the optical characteristic measuring means, for example, a luminance meter can be used as an optical characteristic measuring means. The illuminometer may be able to measure the illumination, chromaticity, a color coordinate and a color temperature at a time. The response of a preferred illuminometer closely corresponds to that of a human being. 
     The optical characteristic value which the illuminometer can measure, as generally known, Ex[lx], x, y, u′, v′, X, Y, Z, T CP [K]. Here, Ex[lx] indicates an illuminance and x, y, u′ and v′ indicate chromaticity. X, Y and Z indicate color coordinates. T CP [K] indicates a color temperature. 
     The electric power characteristic measuring means  620  may measure the electric power characteristic value of the LED lamp. The electric power characteristic measuring means  620  may include, for example, a power meter. The electric power characteristic value may be obtained by measuring at least one selected from among an output voltage, power factor, power consumption, total harmonic distortion (THD) of the output voltage, or an input current of the LED lamp. 
     Through a predetermined numerical expression for obtaining a value for determining whether the quality of the LED lamp is good or poor based on the optical characteristic value and the electric power characteristic value, the arithmetic means  630  may convert the optical characteristic value and the electric power characteristic value into values for determining whether the quality of the LED lamp is good or poor. The predetermined numerical expression (i.e., a conversion expression) may include a numerical expression for obtaining speed of light, color temperature, light efficiency, color coordinate X, or color coordinate Y. For example, numerical expressions related to the parameters described above will be described in the following equations 1 to 5.
 
speed of light= EX[lx]× 1  Equation (1)
 
color temperature= Tcp+ 2  Equation (2)
 
light efficiency=speed of light/power consumption×correlation coefficient  Equation (3)
 
color coordinate  X=X+ 1  Equation (4)
 
color coordinate  Y=Y+ 1  Equation (5)
 
     The quality determining means  640  may determine whether the value for determining whether the quality of the lamp is good or poor is within a predetermined range. That is, if the value is within the predetermined range, the quality determining means  640  may determine that the quality of the lamp is good. If the value is not within the predetermined range, the quality determining means  640  may determine that the quality of the lamp is poor. The determining value for the quality of the lamp may include at least one of speed of light, color temperature of light, light efficiency, color coordinate X, or color coordinate Y of the LED lamp. If all the determining values for the quality of the lamp are within the predetermined range, the quality determining means  640  may determine that the quality of the LED lamp is good. This means that if any one of the determining values for the quality of the LED lamp is not within the predetermined range, corresponding optical characteristic or electric power characteristic is not satisfied, so that the quality determining means  640  may determine that the quality of the LED lamp is poor. 
     In this case, in order to determine the quality of the LED lamp in accordance with a user&#39;s selection, the quality determining means  640  can make use of not only speed of light, color temperature of light, light efficiency, and color coordinates but also a value measured by the optical characteristic measuring means  610  or the electric power characteristic measuring means  620 . 
       FIG. 5  is a flowchart showing a method for testing the LED lamp according to an exemplified embodiment.  FIG. 5  together with  FIG. 4  will be described. 
     First, the optical characteristic value of the LED lamp may be measured by using the optical characteristic measuring means  610  and the electric power characteristic value of the LED lamp may be measured by using the electric power characteristic measuring means  620  (S 100 ). 
     After the steps of S 100  are completed, through a predetermined numerical expression for obtaining the value for determining whether the quality of the LED lamp is good or poor based on the optical characteristic value and the electric power characteristic value, the optical characteristic value and the electric power characteristic value may be converted by the arithmetic means  630  into the values for determining whether the quality of the LED lamp is good or poor (S 200 ). The predetermined numerical expression may provide a standard for allowing a user to determine whether the quality of the LED lamp is good or poor in accordance with test data collected through repetitive measurements. That is, the predetermined numerical expression may change according to the kind of the LED lamp. 
     For example, in a conventional technology, testing the quality of the lamp may be performed by using speed of light, color temperature, light efficiency, a color coordinate value, or the like which are may be directly measured by an integrating sphere, etc. Here, when, by using data repeatedly measured several times, the optical characteristic values measured by the illuminometer and the like are compared with values actually measured by the integrating sphere, a certain correlation may be obtained. Based on such a constant correlation, the values measured by using only the optical characteristic measuring means  610  such as the illuminometer of this embodiment may be converted into the values measured by the integrating sphere, so that the converted values can be readily used to determine whether the quality of the LED lamp is good or poor. 
     After the step of S 200 , the quality determining means  640  may determine whether the value for determining whether the quality of the lamp is good or poor is within a predetermined range (S 300 ). That is, if the value is within the predetermined range, the quality determining means  640  may determine that the quality of the lamp is good (S 410 ). If the value is not within the predetermined range, the quality determining means  640  may determine that the quality of the lamp is poor (S 420 ). 
     This embodiment may provide a LED lamp testing method described above through the steps of S 100  to S 420 , thereby overcoming problems, for example, excessive test time, excessive test cost, and impossibility of a total test which are generated by using the integrating sphere. 
       FIG. 6  shows an example of parameter input of the optical characteristic value and the electric power characteristic value of an exemplary embodiment. Referring to  FIG. 6 , the illuminometer and a power meter may be used as an optical characteristic measuring means and an electric power characteristic measuring means respectively. 
     Symbols of Ex[lx], x, y, u′, v′, X, Y, Z and TCP[° C.] (hereinafter, each symbol has the same meaning as the meaning defined in  FIG. 4 ) can be set on the left side of  FIG. 6 . An output voltage, power factor, power consumption, total harmonic distortion (THD) of the output voltage, and an input current of the LED lamp can be set on the right side of  FIG. 6 . 
     A conversion expression for obtaining the speed of light, color temperature, light efficiency, color coordinate X, or color coordinate Y can be set in the bottom left side of  FIG. 6 . A speed of light, color temperature, light efficiency, color coordinate X, and color coordinate Y can be set in the bottom right side of  FIG. 6 . Particularly, it is possible to measure the speed of light during the testing of an LED lamp. In this embodiment, it is possible to simply measure the speed of light through the measurement of the illuminance of the light and through the predetermined numerical expression. In other words, while it is possible to measure the speed of light only through the use of an integrating sphere in conventional technology, it is possible to simply measure the speed of light without the use of an integrating sphere in this embodiment. 
       FIG. 7  includes a distribution chart of color coordinates measured by using the illuminometer of this embodiment. Referring to the upper part of  FIG. 7 , with detail included in  FIG. 8 , shows and example of data of a measurement result that may include, speed of light, color temperature, light efficiency, input current, Ex[lx], x, y, u′, v′, X, Y, and Z. A graph in the lower part of  FIG. 7  shows chromaticity distribution measured by the illuminometer. That is, such data is measured by the illuminometer and is later converted through predetermined numerical expressions, e.g., the equations (1) to (5). 
       FIG. 8  shows an example of measurement result data obtained by using the illuminometer and a power meter of this embodiment.  FIG. 8  shows speed of light, color temperature, light efficiency, input current, Ex[lx], x, y, u′, v′, X, Y, Z, voltage, current, power factor, power consumption, and V THD in order. For example, as a Pass/Total it can be seen that an LED lamp having an order of 41 has passed 36th the quality test and five LED lamps have failed the quality test prior to the quality test of the LED lamp having an order of 41. 
     Further, it can be understood that an LED lamp having an order of 52 has passed 44th the quality test and eight LED lamps have failed the quality test prior to the quality test of the LED lamp having an order of 52. 
     This embodiment is not limited to the embodiment described above and the accompanying drawings. The scope of rights of this embodiment is intended to be limited by the appended claims. It will be understood by those skilled in the art that various substitutions, modification and changes in form and details may be made therein without departing from the spirit and scope of this embodiment as defined by the appended claims.