Abstract:
A LED light source measuring instrument includes a shell portion and a test portion. The shell portion supports the test portion. The test portion includes a carrier plate for placing a LED light source to be tested. A conductive structure is set on the carrier plate for electrically connecting with an underside surface of the LED light source; a cooling chip is set on the carrier plate; a vacuum suction device is provided for generating a vacuum force on the test portion for securely attaching the LED light source to the carrier plate. The cooling chip is used for controlling the temperature of the LED light source within a limited range. A fan is provided for generating a cooling airflow to the LED light source. A heat sink fin extends from the carrier plate toward the fan.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to a light emitting diode (LED) light source measuring instrument, and particularly relates to a LED positioned and fixed through vacuum force during measurement. The measuring instrument can provide constant temperature environment, without light blocking, easy operation and high precision, suitable for measuring any different sizes, shapes, structures and types of the LED. 
         [0003]    2. Description of Related Art 
         [0004]    An optical and electrical measuring system of LED light source is used by inserting a measuring instrument which carries a well-positioned LED light source into an integrating sphere; through connecting a peripheral spectrum analyzer, an electrical parameter measurement instrument and a LED power controller, the chromaticity coordinate, the color temperature, the color rendering index, the color tolerance adjustment, the wavelength, the color purity, the luminous flux, the voltage, the current and the power, etc., of the LED light source can be detected. The typical LED light source used for the lighting fixture is the surface mounted technology (SMT) type LED, which is suitable for mass production. But there are many differences among the SMT LED light sources regarding the sizes, shapes, structures and types. 
         [0005]    The electrode plates of the LED light source  203  for connecting with the power source as shown in  FIG. 1  include a base positive electrode plate  2032  and a base negative electrode plate  2033  connecting with a backside of the LED light source  203  which is opposite to the light emitting surface  2031  of the LED light source  203 ; a longitudinal positive electrode plate  2132  and a longitudinal negative electrode plate  2133  are extending toward the longitudinal direction; a lateral positive electrode plate  2232  and a lateral negative electrode plate  2233  continue extending toward the lateral direction and parallel with the base positive and negative electrode plates  2032 ,  2033 . In other prior arts they do not have the structure with the lateral positive electrode plate  2232  and the lateral negative electrode plate  2233 . Due to the miniaturization trend and cost considerations, manufacturers only provide the SMT LED light source with the base positive and negative electrode plates  2032 ,  2033 . Also, since the test environment lacks temperature control, the measured LED light source  203  always stay in the transient state of temperature rise. Thus cannot clearly define the long-term stability of the steady state test conditions, resulting in the test data lack of reproducibility. Especially for the power type LED with power more than 0.5 watts which is commonly used in lighting industry. Due to a lack of the thermal design or improper design of the prior art measuring instrument, the LED light source  203  may far exceed the allowable temperature limit because of the rapid temperature rising, and damage the LED light source  203 , rendering the measurement result totally meaningless. 
         [0006]    In prior art, the measuring instrument of LED light source can be divided into two types, a pressed-type measuring instrument  1   a  shown in  FIG. 2 , and a pushed-type measuring instrument  1   b  shown in  FIG. 3 . The pressed-type measuring instrument  1   a  includes a shell portion  10   a  made of a metal material in a hollow cylinder shape, and a testing portion  20   a  located at the opening end of the shell portion  10   a.  The size of an upper stage section  101   a  is matched with the entrance of the integrating sphere. The testing portion  20   a  is installed into the integrating sphere, then positioned by a stepped surface  103  which is located between the upper stage section  101   a  and a rear section  102   a.  The testing portion  20   a  is made of a non-metallic carrier plate  201   a  which is fixedly arranged at the opening end of the shell portion  10   a;  a pressed seat  301  is fixed on the carrier plate  201   a,  wherein the pressed seat  301  is made of metallic materials. A metal position adjustable bolt  302  is arranged on the pressed seat  301  along the radial direction. The nuts of the adjustable bolts  302  are connected with the different polarity power source, become as a positive electrode  205   a  and a negative electrode  210   a  which supply the power to the LED light source  203 . A supporting seat  303  is arranged inside the shell portion  10   a  and supports an axial spring member  304 . An inverted U-shaped top plate  305  is on the top of the axial spring member  304 , and moves upward by spring expansion. The top plate  305  is limited and can only slide axially through the size matching between the cylindrical wall of the top plate  305  and the wall surface of the central through hole of the carrier plate  201   a.  The central region of the end surface of the top plate  305  is the electrically insulating under test zone. 
         [0007]    When the pressed-type measuring instrument  1   a  is not placed with the LED light source  203 , the end surface of the top plate  305  directly contact with the positive and negative electrodes  205   a,    210   a  of the adjustable bolts  302 . When operating, the LED light source  203  is placed on the pressed-type measuring instrument  1   a,  first; then the top plate  305  is pressed to adjust the position of the positive and negative electrodes  205   a,    210   a  according to the size of the lateral positive and negative electrode plates  2232 ,  2233  of the LED light source  203 , according to  FIG. 1 . The LED light source  203  is thus placed in the under test zone of the top plate  305 , and makes the positive and negative electrodes  205   a,    210   a  of the measuring instrument  1   a  compressing the corresponding lateral positive and negative electrode plates  2232 ,  2233  of the LED light source  203 , respectively. To achieve the under test state, the LED light source  203  is sandwiched between the top plate  305  and the pair of electrodes  205   a,    210   a  of the adjustable bolt  302 . 
         [0008]    Since the pressed seat  301 , the adjustable bolts  302  and the pair of electrodes  205   a,    210   a  of the pressed-type measuring instrument  1   a  are necessarily arranged above the light emitting surface  2031  of the LED light source  203 , serious light blocking will further underestimate the measured luminous flux value, and the application of the pressed-type measuring instrument  1   a  is limited only in a few of the lateral positive and negative electrode plates  2232 , 2233  of the LED light source  203 . Using this measuring instrument  1   a  to measure different sizes and shapes of LED light source  203  has its limitation and operating inconvenient, particularly in the non-temperature controlled test environment, resulting in the lack of reproducibility of measurement data, even causing the damage of the LED light source  203 . Thus, the pressed-type measuring instrument  1   a  has serious limitations and shortcomings in both measuring quality and application level. 
         [0009]      FIG. 3  shows the pushed-type measuring instrument  1   b.  The main differences between the pressed-type and pushed-type measuring instruments  1   a,    1   b  are that: There is a flat shallow trench  412  through a center of a carrier plate  201   b;  the bottom of a negative electrode assembly  402  is fixed inside the trench  412 ; a positive electrode assembly  401  can slide freely along the trench  412 ; the positive and negative electrode assemblies  401 ,  402  are made of electrically insulating material. Two metal thimbles  205   b,    210   b  extend respectively from the positive and negative electrode assemblies  401 ,  402  toward the LED light source  203 . The two metal thimbles  205   b,    210   b  are used to electrically connect with a power source thereby making the two metal thimbles  205   b,    210   b  form a pair of positive and negative electrodes  205   b,    210   b  for the pushed-type measuring instrument  1   b.    
         [0010]    The movement of the positive electrode assembly  401  is along a long trench  409  which opens through the carrier plate  201   b  to communicate with the trench  412 . A spring member  404  is arranged inside a shell portion  10   b  by a screw passing through the long trench  409  to connect with the positive electrode assembly  401  so that the positive electrode assembly  401  is fixed to a slider  405 . The slider  405  is in the middle of the spring member  404 . One side of the slider  405  along the radial direction has a guide rod  406 , the end of the guide rod  406  is extending to but no over the outer wall surface of an upper stage section  101   b.  The other side of the slider  405  along the radial direction locates a fixing screw  407  which extends through the upper stage section  101   b,  and allows a spring  408  extend into a corresponding blind hole of the slider  405 . The blind hole, the guide rod  406  and the fixing screw  407  are coaxially aligned. When operating the pushed-type measuring instrument  1   b,  gently push a certain distance of the guide rod  406  to enable the slider  405  sliding along the trench  412 , making the positive electrode assembly  401  moving the same distance away from the fixed negative electrode assembly  402  to place the LED light source  203  properly between the electrode assemblies  401 ,  402 . When the pushed force on the guide rod  406  is released, the positive electrode assembly  401  moves close to the LED light source  203  to electrically engage the longitudinal positive electrode plate  2132 . 
         [0011]    According to the size of the LED light source  203 , the positive and negative electrodes  205   b,    210   b  of the positive and negative electrodes assembly  401 ,  402  of the pushed-type measuring instrument  1   b  contact with and supply power to the longitudinal positive and negative electrode plates  2132 ,  2133  of the LED light source  203 . However, the heights of the positive and negative electrode assemblies  401 ,  402  of the pushed-type measuring instrument  1   b  and the longitudinal positive and negative electrode plates  2132 ,  2133  of the LED light source  203  are fixed and may not match each other. Additionally, the amount of the displacement of the slider  405  is limited via pushing the guide rod  406 , the size of the LED light source  203  is varied in the market, and the LED light source  203  may not have the longitudinal positive and negative electrode plates  2132 ,  2133 . Therefore, using the same pushed-type measuring instrument  1   b  to measure different sizes and shapes of the LED light source  203  has its limitation. The pushed-type measuring instrument  1   b  is only suitable for the type of the LED light source  203  with the longitudinal electrode plates  2131 ,  2133 . Particularly in the non-temperature controlled test environment where the steady-state test conditions cannot be clearly defined. Thus, the pushed-type measuring instrument  1   b  has its limitations and shortcomings in measuring quality and the application level. 
         [0012]    In order to reduce the impact of the temperature rise during the measurement process, the current market has pulsed DC power supply for measuring the LED light source  203 , and claimed that the measuring instrument can retrieve the transient data of the optical and electrical parameters within a fraction of a second after lighting the LED light source  203 . However, any heat sources including the LED light source  203  in the initial temperature rise transient process must be the fastest and most dramatic particular in the power type LED. After a long-term experimental confirmation, under the test conditions which do not result in the damage of the LED light source  203 , evidenced that the initial luminous flux of these transient data are up more than double that of the long-term stability of the steady state flux data. The transient flux data show very big differences at different time instants for initial lighting and lose the reproducibility when detecting the same LED light source  203 , resulting in only the LED manufactures strongly advocate and provide such transient data to the end users. However, for the LED lighting industry, the useful reference value should pay attention to the long-term steady state lighting performance. The initial transient data provided by the vendors are completely meaningless. The standardization of the LED light source  203  measurement method (CIE 127: 2007, MEASUREMENT OF LEDS) indicated that the above initial transient data must be clearly correlated to the steady state data, but the correlation will be different with different manufactures of LEDs. For the majority of the lighting applications, end users are completely unable to understand the meaning of the norms of transient data; therefore, the transient data of the LED light source  203  lack the practicability. Accordingly, measurement of the LED light source  203  still needs to be in line with the practical application and has long-term reproducibility and stable data. 
         [0013]    Therefore, it is necessary to provide a way for non-destructive measurement of LED light source under the well-defined constant temperature steady state conditions, and the LED light source measuring instrument with no light blocking, easy operation, high precision and versatility. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Many aspects of the present LED light source measuring instrument can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present LED light source measuring instrument. In the drawing, all the views are schematic. 
           [0015]      FIG. 1  is a perspective view of a typical LED light source. 
           [0016]      FIG. 2  is a schematic cross sectional view of a prior art measuring instrument for measuring the characteristics of the LED light source of  FIG. 1 . 
           [0017]      FIG. 3  is a schematic cross sectional view of another prior art measuring instrument. 
           [0018]      FIG. 4  is a schematic cross sectional view of a LED measuring instrument of the first embodiment of the present disclosure. 
           [0019]      FIG. 5A  is a top perspective view of a test portion of the LED measuring instrument of  FIG. 4 . 
           [0020]      FIG. 5B  is a bottom perspective view of the test portion of the LED measuring instrument of  FIG. 4 . 
           [0021]      FIG. 6  is a schematic diagram of a telescopic assembly of the LED measuring instrument of  FIG. 4 . 
           [0022]      FIGS. 7A and 7B  are schematic diagrams of two kinds of electrodes of the LED measuring instrument of  FIG. 4 . 
           [0023]      FIG. 8  is a schematic cross sectional view of a LED measuring instrument of the second embodiment of the present disclosure. 
           [0024]      FIG. 9A  is a top perspective view of a test portion of the LED measuring instrument of  FIG. 8 . 
           [0025]      FIG. 9B  is a bottom perspective view of the test portion of the LED measuring instrument of  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION 
       [0026]      FIG. 4  is a schematic cross sectional view of a LED measuring instrument of the first embodiment of the present disclosure.  FIGS. 5A and 5B  are a top and a bottom perspective view of a test portion of the LED measuring instrument of  FIG. 4 , respectively.  FIG. 6  is a schematic diagram of a telescopic assembly of the LED measuring instrument of  FIG. 4 .  FIGS. 7A and 7B  are schematic diagrams of two kinds of electrodes of the LED measuring instrument of  FIG. 4 . The measuring instrument includes a shell portion  10  and a test portion  20 . The shell portion  10  is a hollow cylinder and has at least one side opening for receiving the test portion  20 . The outer peripheral wall surface of the cylinder axially extending from the opening into a thinner upper stage section  101 , and forms a right angle stepped surface  103  between the thinner upper stage section  101  and a thicker rear section  102 . The outer peripheral wall size and shape of the upper stage section  101  match with the inner surrounding wall surface of the tubular entrance (not shown) of an integrating sphere (not shown). The stepped surface  103  abuts against the tubular end of the entrance, to achieve the test portion  20  inserted and positioned into the integrating sphere, so that the LED light source  203  is in under test status. 
         [0027]    The test portion  20  includes a carrier plate  201  embedded in an opening end of the shell portion  10 , and a heat sink fin  306   a  axially extending from a side of the carrier plate  201  opposite the LED light source  203  and toward the inside of the shell portion  10 . The heat sink fin  306   a  is around the periphery of a central cylinder  312   a,  and extending radially with a plurality of spiral plates. The heat sink fin  306   a  enables the carrier plate  201  to increase heat dissipation area and enhance the heat conducting path, whereby heat generated by the LED light source  203  on the outer end surface of carrier plate  201  can be dissipated quickly. A space is defined between the end edge of the plurality of the spiral plate and the inner wall of the shell portion  10  for smoothing the path of the cooling airflow. The central cylinder  312   a  toward the opening end of the heat sink fin  306   a  has a cylinder lid  315 . The center of the outer end surface of the carrier plate  201  is an electrically insulating under test zone  202  for placing the LED light source  203 , with at least one air hole  204  at the center of the under test zone  202  passes through the carrier plate  201  and connects with a space surrounded by the central cylinder  312   a.    
         [0028]    In the present embodiment, it uses one air hole  204  for illustration. At least one pair of electrodes  205 ,  210  are located at a side of the carrier plate  201  exposed outwardly and positioned neighboring opposite sides of the air hole  204  for connecting with external control power (not shown) to conduct positive and negative voltages.  FIG. 5A  shows three pairs of electrodes  205 ,  210 , wherein each pair of the electrodes  205 ,  210  is constituted by a metal sleeve  2054  (outer diameter less than 3 mm), inside the metal sleeve  2054  being equipped with a telescopic assembly  2050  of a metal spring  2051 . One of a telescopic assembly  2050   a  is composed of a sleeve  2054   a  with two end openings, the spring  2051  is equipped inside the sleeve  2054   a,  and both ends of the spring  2051  are respectively connected to a thimble  2052  which is axially telescopic toward the corresponding opening of the sleeve  2054   a,  as shown in  FIG. 6(A) . Another telescopic assembly  2050   b  is composed of a sleeve  2054   b  with one end opening, the spring  2051  is equipped inside the sleeve  2054   b  and connected to a thimble  2052  which is axially telescopic toward the opening of the sleeve  2054   b,  as shown in  FIG. 6(B) . Each of the electrodes  205 ,  210  via the corresponding sleeve  2054  is perpendicularly extended and fixed in the corresponding pore of the carrier plate  201  and electrically insulating from the carrier plate  201 . The pores are connected with the space surrounded by central cylinder  312   a;  one end of the thimble  2052  slightly protrudes upwardly beyond the surface of the under test zone  202  when the LED light source  203  is not placed on the under test zone  202 . 
         [0029]    Through a flexible tube  206 , which is connected with the central cylinder  312   a  and fixed in the cylinder lid  315  and extends through a wall hole  104  passed through the rear section  102  of the shell portion  10 , the air hole  204  is connected with the vacuum pump  50  outside the shell portion  10 . The positive and negative electrodes  205 ,  210  are connected to an external control power supply (not shown) via two electric wires  208   a  using a plug  209   a,  to supply the power to the LED light source  203 . One of the adopted ways, as shown in  FIGS. 4 and 7A , the two electric wires  208   a  separately connected to the three thimbles  2052  at bottoms of the telescopic assemblies  2050   a,  and the three sleeves  2054   b  at bottoms of the telescopic assemblies  2050   b.  In another embodiment, as shown in  FIG. 7B , three metal seats  2056  set on the tops of three branches of the electric wire  208   a  whereby the three metal seats  2056  are respectively attached to the bottoms of the three sleeves  2054   b  of the telescopic assemblies  2050   b.    
         [0030]    The under test zone  202  of the measuring instrument  1  also sets an annular shape cooling chip  307  (also known as thermoelectric cooler, semiconductor refrigeration, heat pump, etc.) surrounds the electrodes  205 ,  210 . The cooling chip  307  consists of a plurality of cooling dies made from different types of materials such as Bismuth telluride packaged into two electrically insulating ceramic plates on both sides. When DC current flows through the chip  307  operated by the Peltier effect to create a heat flux between the junction of adjacent two dies and brings heat from one side to the other, so that one side gets cooler while the other gets hotter. The hot side is attached to a heat sink so that it remains at ambient temperature, while the cool side goes below room temperature. The present disclosure uses the annular cooling chip  307 , bottom side of the annular plate of the cooling chip  307  functions as a heating (heat dissipating) surface and tightly attached to the corresponding grooved bottom surface of the carrier plate  201 , and upper side of the annular plate functions as a cooling (heat absorbing) surface and has the same high with the outer surface of the under test zone  202 . Practical application of the cooling chip may also use other shapes. Two electric wires  208   b  are electrically connected with the cooling chip  307  using a plug  209   b  connected to an external control power supply (not shown), to supply the power to the cooling chip  307 . The electric wires  208   b  pass through the carrier plate  201 , the heat sink fin  306   a  and the wall hole  104  to an outside of the rear section  102  of the shell portion  10 . 
         [0031]    A thermal sensor (e.g., thermistors or thermocouples) (not shown) is stuck on the cooling surface of the cooling chip  307 ; through the thermal sensor connecting the temperature control circuit (not shown) and setting the temperature of the cooling surface via the temperature monitor (not shown), the cooling surface is maintained at low temperature (e.g., 10° C. or 20° C.) during measurement. Heat released from LED light source  203  absorbed on the under test zone  202  is absorbed by the cooling surface. So that, the LED light source  203  is measured at a controlled low temperature, thereby the LED light source  203  is prevented from being damaged by excessive temperature rise. In order to achieve above mentioned low temperature measurement to prevent the heating surface of the cooling chip  307  from being unable to dissipate the heat from the cooling surface whereby the temperature will rise and the thermal energy will backflow to the cooling surface, the present disclosure discloses the use of the carrier plate  201  to conduct the heat released from heating surface of the cooling chip  307  to the heat sink fin  306   a.  In addition, in the rear section  102  of the shell portion  10  close to the inner wall surface of the bottom there is provided with a fan  308 , wherein the fan  308  blows the cold air from outside into the heat sink fin  306   a;  the spiral direction of the spiral heat sink fin  306   a  is consistent with the rotation direction of the fan  308 , enabling the cooling airflow easily lead to the heat sink fin  306   a  to remove heat therefrom. 
         [0032]    When the measuring instrument  1  has not been inserted into the integrating sphere, the fan  308  sucks the cooling airflow via a plurality of lateral air inlets  310   a,  wherein the lateral air inlets  310   a  partially surround the fan  308  and are located around the lower side of the rear section  102 . When the measuring instrument  1  inserted into the integrating sphere, the fan  308  sucks the cooling airflow via both a plurality of axial air inlets  310   b  located at the bottom side of the rear section  102  and also the lateral air inlets  310   a.  At air outlet of the fan  308  there is a tapered wind guider  309  toward the heat sink fin  306   a;  the outlet of the wind guider  309  covers the axial free end of the heat sink fin  306   a,  in order to accelerate and guide the converged cooling airflow to the heat sink fin  306   a  and the carrier plate  201 . An endothermic airflow of the neighbor heat sink fin  306   a  via the spacing between the side edge of the heat sink fin  306   a  and the inner wall of the upper stage section  101  is guided into the annular channel formed between the inner wall surface of the upper stage section  101  and the outer wall surface of the wind guider  309 . Then via a plurality of air outlets  311  partly defined in the wall surface of the rear section  102 , the endothermic airflow released from the LED light source  203  and the heating surface of the cooling chip  307  is discharged out of the integrating sphere. 
         [0033]    When operating the measuring instrument  1  to measure the LED light source  203 , first step is to turn on the vacuum pump  50 , and then place the LED light source  203  on the under test zone  202 , make the central bottom side of the LED light source  203  abut on the air hole  204 , and make the base positive and negative electrode plates  2032 ,  2033  abut against to the at least one pair of electrodes  205 ,  210  corresponding protruding thimbles  2052  of the measuring instrument  1 . The light emitting surface  2031  of the LED light source  203  is at the top side thereof, which is opposite to the bottom side of the base positive and negative electrode plates  2032 ,  2033 . Through a vacuum force provided by the vacuum pump  50 , the LED light source  203  is attached and fixed on the under test zone  202  via the vacuum force in the air hole  204 . Simultaneously, at least one pair of the thimble  2052  with different polarity tightly contacts on the base positive and negative electrode plates  2032 ,  2033  respectively of the LED light source  203 . After the predetermined temperature of the cooling surface of the annular cooling chip  307  is set and the fan  308  is turned on, the external power is supplied to the cooling chip  307 ; then the measuring instrument  1  is inserted into the entrance of the integrating sphere. Adjust and stabilize the external control power until the operating current and voltage of the LED light source  203  meets the specification; then, turn on the power for lighting the LED light source  203  inside the integrating sphere. Confirm the temperature of the cooling surface reaches stability state by the temperature display, and startup the optical and electrical properties automatic measurement system of the LED light source  203 . When measurement is completed, turn off the external control power to extinguish the LED light source  203 , then remove the measuring instrument  1  from the integrating sphere, and remove the LED light source  203 , continue to place another LED light source  203  on the under test zone  202  for measurement. 
         [0034]    Compared to the conventional LED light source measuring instruments  1   a,    1   b,  since the present embodiment is via a vacuum pump  50  to provide the vacuum force at the bottom of the LED light source  203 , the present disclosure achieves the LED light source  203  not only closely attached and easily positioned on the most front surface of the measuring instrument  1 , but also electrically connected to the base positive and negative electrode plates  2032 ,  2033 , completely excluding the light blocking shortcoming of the conventional measuring instruments  1   a,    1   b,  and completely avoiding the temperature rise of the LED light source  203  which may causes measurement uncertainty and destructive risk; moreover the measurement instrument  1  of the present disclosure has a more simplified structure than conventional measuring instruments  1   a,    1   b.  In present disclosure, power can be supplied to any SMT type LED light source with base positive and negative electrode plates  2032 ,  2033 ; the present disclosure can be used to measure different sizes, shapes, structures and types of the LED light source without any restriction, ensure the excellent measurement quality and extremely versatile of the LED light source measuring instrument  1 . 
         [0035]      FIG. 8  is an assembled schematic cross-sectional view of the second embodiment.  FIGS. 9A and 9B  respectively are a top and a bottom perspective view of the test portion of the measuring instrument of  FIG. 8 . The main difference between the present embodiment and the foregoing embodiment is that: To simplify the pairs of electrodes  205 ,  210  as two sheet metal strips laid and slightly protrude out of the surface of a carrier plate  201   c  to form a pair of electrodes  205   c,    210   c  which electrically insulating with the carrier plate  201   c.  Practical application of the sheet metal electrodes may also use other shapes. The cooling surface of the cooling chip  307  is arranged on the same plane with the electrodes  205   c,    210   c.  Therefore, when using the vacuum force to attach and fix the LED light source  203  on the under test zone  202 , an electrical connection of the LED light source  203  with electrodes  205   c,    210   c  is also achieved. 
         [0036]    Further, the pair of the sheet metal strip electrodes  205   c,    210   c  is electrically connected to the external control power supply via two electric wires  208   a  directly passing through the carrier plate  201   c  and led out of a shell portion  10   c  via a heat sink fin  306   b.  That is, the wires  208   a  are unnecessary to be led out through the opening end of a central cylinder  312   b.  Therefore, the diameter of the central cylinder  312   b  can be decreased, thereby increasing the density of the heat sink fin  306   b  close to the center of the under test zone  202 . Such design increases the efficiency of heat dissipation, also enables a direct connection of the flexible tube  206  with the opening of the central cylinder  312   b,  whereby the cylinder lid  315  of the first embodiment can be eliminated in this embodiment. 
         [0037]    Furthermore, in the present embodiment a radially extending straight plate heat sink fin  306   b  connected with the central cylinder  312   b  is proposed for substituting the radially extending spiral plate heat sink fin  306   a  connected with the central cylinder  312   a,  wherein the straight fin is more easily to manufacture and accordingly has a lower cost. To achieve the easier manufacture purpose, practical application of the heat sink fin may also use other types. For example, the different shapes of central cylinder and pin fin, louver fin, stack fin, etc. Obviously, the measuring instrument  1   c  in addition to achieve the same benefits as the forgoing embodiment and its advantages beyond the conventional technology, further has the streamline structure, to simplify the process and reduce the cost. 
         [0038]    In the above embodiment the technical features and the reached effect of the present disclosure are clearly described, which include:
   A LED light source measuring instrument is provided, which has a high precision ability to measure the optical and the electrical properties; vacuum force is used to easily attach and fix the SMT type LED on the under test zone; and the LED is powered by contacting between the base positive and negative electrode plates of the LED and the positive and negative electrodes of the measuring instrument. The LED light source is maintained at the most front surface of the measuring instrument, to overcome the light blocking shortcoming of the conventional measuring instrument, and to achieve high precision optical and electrical performance of the measuring instrument.   
 
         [0040]    The present disclosure provides a LED measuring instrument which can maintain the LED light source under different temperature protected conditions to carry out the steady state optical and electrical measurement. Via the cooling chip positioned near the electrodes, the present disclosure provides high efficient heat dissipation and smoothes the path of the cooling airflow, whereby the heat released from the LED light source and the heating surface of the cooling chip can be exhausted out of the LED measuring instrument and the integrating sphere quickly. The quick release of the heat from the LED light source can effectively eliminate the measurement errors and risk of damage to the LED light source caused by rapid temperature rise of the LED light source. 
         [0041]    The present disclosure provides an optical and electrical performance measuring instrument which can be applied to any sizes or types of SMT type LED, supply power to any SMT type LED light source with base positive and negative electrode plates, regardless of the size and type of the LED whether with the longitudinal or lateral positive and negative electrode plates; thus all the diversified SMT type LEDs measurement can be achieved by one LED measuring instrument of the present disclosure. 
         [0042]    The present disclosure provides a SMT type LED measuring instrument with a simple structure, easy operation, without the positioning fixture with complex structure of the conventional measuring instrument. Thus can simplify the operation for installment and removal of the LED light source, achieve streamline the cost and simplify the process of the measuring instrument, and ensure the measurement quality and the long term reliability. 
         [0043]    Although the present disclosure has been specifically described on the basis of this exemplary embodiment, the disclosure is not to be construed as being limited thereto. Various changes or modifications may be made to the embodiment without departing from the scope and spirit of the disclosure.