Patent Publication Number: US-2022232685-A1

Title: Test apparatus, test method, and computer-readable storage medium

Description:
The contents of the following Japanese patent application(s) are incorporated herein by reference:
         NO. 2021-007928 filed in JP on Jan. 21, 2021       

     BACKGROUND 
     1. Technical Field 
     The present invention relates to a test apparatus, a test method, and a computer-readable storage medium. 
     2. Related Art 
     A method is known in which one of a pair of LEDs to be inspected is caused to emit light and the other is caused to receive the light, and optical characteristics of the LED are inspected using a current value of a current output by a photoelectric effect (see, for example, Patent Documents 1 and 2). 
     CITATION LIST 
     Patent Document 
     
         
         Patent Document 1: Japanese translation publication of PCT route patent application No. 2019-507953 
         Patent Document 2: Japanese Patent Application Publication No. 2010-230568 
       
    
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an example of an overall view illustrating an outline of a test apparatus  100  for testing an LED panel  15 . 
         FIG. 2  is an example (A) of a side view and an example (B) of a plan view of the LED panel  15  in a state of being connected to the test apparatus  100 . 
         FIG. 3  is an example of an explanatory diagram for explaining a state in which the LED panel  15  is connected to the test apparatus  100 . 
         FIG. 4  is an example of a flowchart illustrating a flow of a test method by the test apparatus  100 . 
         FIG. 5  is a diagram illustrating an example of a computer  1200  in which a plurality of aspects of the present invention may be embodied in whole or in part. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all combinations of features described in the embodiments are essential to the solution of the invention. In the drawings, the same or similar parts are denoted by the same reference numerals, and redundant description may be omitted. 
       FIG. 1  is an example of an overall view illustrating an outline of a test apparatus  100  for testing an LED panel  15 . In addition,  FIG. 2  is an example (A) of a side view and an example (B) of a plan view of the LED panel  15  in a state of being electrically connected to the test apparatus  100 . In addition,  FIG. 3  is an example of an explanatory diagram for explaining a state in which the LED panel  15  is connected to the test apparatus  100 . Note that, in the specification of the present application, in a case where the term “being electrically connected” is defined, it is intended to be electrically connected by contact or to be electrically connected in a non-contact manner. 
     In  FIG. 1 , an X axis having a +X direction in the right-hand direction facing the paper surface, a Z axis having a +Z direction in the upper direction facing the paper surface, and a Y axis having a +Y direction in the front direction facing the paper surface are illustrated so as to be orthogonal to each other. Hereinafter, description may be made using these three axes. 
     As illustrated in  FIG. 2 , the LED panel  15  in the present embodiment includes a plurality of cells  12  formed in a panel (PLP) such as a glass base having a substantially rectangular outer shape provided with a wiring  11 . The plurality of cells  12  are arranged in a row direction (X direction in the drawing) and a column direction (Y direction in the drawing) in the LED panel  15 . Each cell  12  may correspond to a pixel of the LED panel  15 . Note that, in  FIG. 2 , a part of the LED panel  15  is divided by wavy lines in order to illustrate some LEDs  10  and wirings  11  inside the LED panel  15 . In addition, in  FIG. 3 , the LED  10  and the wiring  11  inside the LED panel  15  are illustrated in order to describe a state in which the LED panel  15  is connected to the test apparatus  100 . Note that the configuration of the LEDs  10  and the like illustrated in  FIG. 2  and  FIG. 3  is merely an example, and other configurations and numbers may be used. 
     Each of the plurality of cells  12  includes one or two or more LEDs  10 . 
     In the present embodiment, each cell  12  includes three LEDs  10  corresponding to three colors of RGB as an example, as indicated by a broken line frame in  FIG. 2  and  FIG. 3 . 
     As an example, the LED panel  15  in the present embodiment is driven by passive matrix driving. As illustrated in  FIG. 2 , the plurality of LEDs  10  included in the LED panel  15  are arranged in the row direction and the column direction in a state of being electrically connected to each other by the wiring  11 . As illustrated in  FIG. 3 , in each row, the anodes of the plurality of LEDs  10  arranged in the row direction are electrically connected to a row line  11   r  corresponding to the row. In each column, the cathodes of the plurality of LEDs  10  arranged in the column direction are electrically connected to a column line  11   c  corresponding to the column. 
     Here, in the present embodiment, in the plurality of cells  12  arranged in the column direction, a plurality of concolorous LEDs  10  that emit the same color with each other are mutually connected. In the plurality of cells  12  arranged in the column direction, red LEDs  10  are mutually connected by one column line  11   c . Similarly, in the plurality of cells  12 , green LEDs  10  are mutually connected by one column line  11   c , and blue LEDs  10  are mutually connected by one column line  11   c.    
     The LED  10  in the present embodiment is a micro LED having a dimension of 100 μm or less. Note that, instead of the micro LED, the LED  10  may be a mini LED having a dimension larger than 100 μm and equal to or less than 200 μm, an LED having a dimension larger than 200 μm, or another light emitting device such as an LD. For example, the LED panel  15  may be an organic display panel using an organic light emitting diode as each of the plurality of LEDs  10 . 
     The test apparatus  100  uses the photoelectric effect of each LED  10  in the LED panel  15  to collectively test the optical characteristics of the plurality of cells  12  each including the LED  10  on the basis of a photoelectric signal output from the LED  10  that performs irradiation with light. The test apparatus  100  according to the present embodiment includes a substrate  20 , an electrical connection unit  110 , a light source unit  120 , a temperature control unit  126 , a reading unit  115 , a measuring unit  130 , a control unit  140 , a storage unit  145 , a placement unit  150 , and a blocking unit  160 . 
     The substrate  20  holds the LED panel  15 . The substrate  20  is placed on the placement unit  150 . Note that the test apparatus  100  may not include the substrate  20 . 
     The electrical connection unit  110  is electrically connected to the LED panel  15 . More specifically, the electrical connection unit  110  in the present embodiment is electrically connected to the column line  11   c  of each column. As illustrated in  FIG. 3  as an example, the electrical connection unit  110  faces one side surface of the LED panel  15  in the substrate  20 , and is electrically connected by being in contact with the terminal of each column line  11   c  in the one side surface of the LED panel  15 . As a result, the electrical connection unit  110  is connected to one end of each column line  11   c  via the terminal, and is electrically connected to the plurality of LEDs  10 . 
     The electrical connection unit  110  is also electrically connected to the measuring unit  130 . As illustrated in  FIG. 3 , the electrical connection unit  110  is configured such that each of the plurality of column lines  11   c  is independently connected to the measuring unit  130  via the electrical connection unit  110 . 
     The electrical connection unit  110  in the present embodiment is electrically connected by being in contact with the column line  11   c  connecting the plurality of LEDs  10 , but may be electrically connected in a non-contact manner by, for example, electromagnetic induction or near field communication. 
     The light source unit  120  collectively irradiates the plurality of cells  12  with light. The light source unit  120  in the present embodiment irradiates the plurality of LEDs  10  of the plurality of cells  12  with light in a reaction wavelength band of the plurality of LEDs  10  of the plurality of cells  12 . The light source unit  120  in the present embodiment includes a light source  121  and a lens unit  123 . 
     The light source  121  emits light in the reaction wavelength band of the plurality of LEDs  10 . The light source  121  may be, for example, a light source that emits light in a wide wavelength band, such as a xenon light source, or may be a light source that emits light in a narrow wavelength band, such as a laser light source. The light source  121  may include a plurality of laser light sources having wavelengths that are different from each other. Note that, in a case where the reaction wavelength and the light emission wavelength of the LED  10  are different from each other, even if the LED  10  is irradiated with light having the light emission wavelength of the LED  10 , photoelectric conversion does not appropriately occur due to the difference. 
     The lens unit  123  includes one or more lenses, is provided adjacent to the irradiation unit of the light source  121 , and converts the diffused light irradiated from the light source  121  into parallel light  122 . In  FIG. 1 , the parallel light  122  is indicated by hatching. The projection plane of the parallel light  122  in the XY plane covers at least the plurality of cells  12  of the LED panel  15 . In  FIG. 2  and  FIG. 3 , illustration of the light source unit  120  is omitted. 
     The temperature control unit  126  suppresses temperature rise of the plurality of LEDs  10  due to irradiation with the light. The temperature control unit  126  in the present embodiment includes a temperature suppression filter  125  and a filter holding unit  124 . The temperature suppression filter  125  has high light transmittance and absorbs a heat ray of incident light. The filter holding unit  124  is provided adjacent to the lens unit  123  and holds the temperature suppression filter  125 . Note that the temperature control unit  126  may further include a cooler that cools the heat absorbed by the temperature suppression filter  125 . 
     In order to keep the temperatures of the plurality of LEDs  10  constant, the temperature control unit  126  may include, instead of or in addition to the above configuration, a temperature applying apparatus that adjusts the temperatures of the plurality of LEDs  10 , an air blowing mechanism that blows air toward the plurality of LEDs  10 , and the like. In a case where the air blowing mechanism is used, the temperature control unit  126  may further include a static electricity removing unit that prevents the plurality of LEDs  10  from being charged with static electricity when air is blown by the air blowing mechanism. The static electricity removing unit may be, for example, an ionizer. The above described temperature applying apparatus may be provided in the substrate  20  or the like in a manner contacting the LED panel  15 . In addition, the above described air blowing mechanism may be provided on the side of the placement unit  150  in a manner not contacting the LED panel  15 . Note that the test apparatus  100  may not include the temperature control unit  126 . In  FIG. 2  and  FIG. 3 , illustration of the temperature control unit  126  is omitted. 
     The reading unit  115  in the present embodiment includes a row drive unit  116  and a column drive unit  117 . The row drive unit  116  is electrically connected to the anode of the LED  10  via the row line  11   r , and the column drive unit  117  is electrically connected to the cathode of the LED  10  via the column line  11   c.    
     The reading unit  115  reads, for each row of the LED panel  15 , a photoelectric signal obtained by photoelectrically converting light by the LED  10  in each of the two or more cells  12  arranged in the column direction. The reading unit  115  in the present embodiment applies, to one row line  11   r  connected to three LEDs  10  of the cell  12  from which the photoelectric signal is to be read, a positive reference voltage higher than the potentials of the three column lines  11   c  connected to the three LEDs  10 , for example, a ground potential, thereby reading the photoelectric signal output by the three LEDs  10  after photoelectric conversion of light. Note that, as illustrated in  FIG. 3 , a plurality of other cells  12  are also connected to the row line  11   r.    
     While the LED panel  15  is irradiated with light, the reading unit  115  in the present embodiment reads the photoelectric signal from each of the two or more cells  12  arranged in the column direction. As an example, while the light source  121  collectively irradiates the plurality of cells  12  of the LED panel  15  with light, the reading unit  115  sequentially applies the reference voltage to each of the plurality of row lines  11   r  from the negative side of the Y axis to the positive side of the Y axis in  FIG. 3 , thereby reading the photoelectric signal from each of the plurality of cells  12  arranged in the column direction. In the present embodiment, the photoelectric signal flowing from each LED  10  to the column line  11   c  is supplied to the measuring unit  130  via the electrical connection unit  110 . Note that, in  FIG. 2 , a part of the reading unit  115  is divided by a wavy line in order to illustrate the wiring  11  inside the reading unit  115 . 
     The measuring unit  130  measures the photoelectric signal read from each of the plurality of cells  12  and supplied via the electrical connection unit  110 . As illustrated in  FIG. 3 , the measuring unit  130  in the present embodiment is connected to each of the plurality of column lines  11   c  via the electrical connection unit  110 , and individually measures the current value of the current supplied from each column line  11   c . Note that the measuring unit  130  may measure a voltage value corresponding to the current value instead of the current value. In  FIG. 2 , illustration of the measuring unit  130  is omitted. 
     The control unit  140  controls each component of the test apparatus  100 . 
     The control unit  140  in the present embodiment controls the light source  121  of the light source unit  120 , thereby controlling the irradiation time, wavelength, and intensity of the parallel light  122  with which the plurality of cells  12  are collectively irradiated. The control unit  140  in the present embodiment also drives the placement unit  150  such that at least the plurality of cells  12  of the LED panel  15  placed on the placement unit  150  via the substrate  20  can receive light from the light source unit  120  in the blocking unit  160  by controlling the placement unit  150 . Note that the control unit  140  may grasp the position coordinates in the space of the blocking unit  160  and the relative position between the blocking unit  160  and the LED panel  15  on the placement unit  150  by referring to reference data in the storage unit  145 . 
     The control unit  140  further controls the reading unit  115  to read the photoelectric signal from each of the two or more cells  12  arranged in the column direction for each row of the LED panel  15 . The control unit  140  also supplies a voltage used to drive the row drive unit  116  and the column drive unit  117  of the reading unit  115 . 
     The control unit  140  further determines the quality of each of the plurality of cells  12  on the basis of the measurement result of the measuring unit  130 . More specifically, the control unit  140  in the present embodiment determines at least one cell  12  including at least one LED  10  in which the measured photoelectric signal is out of the normal range among the plurality of cells  12  as defective. The control unit  140  refers to the storage unit  145  to perform sequence control of a plurality of configurations in the test apparatus  100  described above. Note that the control unit  140  functions as an example of a determination unit. In  FIG. 2 , illustration of the control unit  140  is omitted. 
     The storage unit  145  stores a measurement result, reference data for determining the quality of each of the plurality of cells  12 , a determination result, reference data for moving the placement unit  150 , a sequence and a program for controlling each component in the test apparatus  100 , and the like. The storage unit  145  is referred to by the control unit  140 . In  FIG. 2 , illustration of the storage unit  145  is omitted. 
     The substrate  20  holding the LED panel  15  is placed in the placement unit  150 . The placement unit  150  in the illustrated example has a substantially rectangular outer shape in a plan view, but may have another outer shape. The placement unit  150  has a function of holding a vacuum chuck, an electrostatic chuck, or the like, and holds the placed substrate  20 . In addition, the placement unit  150  moves two-dimensionally in the XY plane and moves up and down in the Z axis direction by being driven and controlled by the control unit  140 . In  FIG. 1  and  FIG. 2(A) , illustration of the placement unit  150  on the negative direction side of the Z axis is omitted. In addition, in  FIG. 1  and  FIG. 2 , the moving direction of the placement unit  150  is indicated by a white arrow. The same applies to the following drawings. Note that the test apparatus  100  may not include the placement unit  150 . In  FIG. 3 , illustration of the placement unit  150  is omitted. 
     The blocking unit  160  blocks light other than the light from the light source unit  120 . The surface of the blocking unit  160  in the present embodiment is entirely painted black to prevent irregular reflection of light on the surface. In addition, as illustrated in  FIG. 1 , the blocking unit  160  in the present embodiment is provided so as to be in close contact with each of the outer periphery of the light source  121  and the outer periphery of the LED panel  15 , and this configuration blocks light other than the light from the light source unit  120 . Note that the test apparatus  100  may not include the blocking unit  160 . In  FIG. 2  and  FIG. 3 , illustration of the blocking unit  160  is omitted. 
       FIG. 4  is an example of a flowchart for explaining a flow of a test method by the test apparatus  100 . The flow is started when, for example, a user inputs to the test apparatus  100  to start a test of the LED panel  15  with the substrate  20  holding the LED panel  15  placed on the placement unit  150 . 
     The test apparatus  100  executes an electrical connection step of electrically connecting the electrical connection unit  110  to the LED panel  15  (Step S 101 ). As a specific example, the test apparatus  100  may output a command to a conveyance apparatus or the like that conveys the LED panel  15  to dispose the LED panel  15  on the substrate  20  so that the LED panel  15  is connected to the reading unit  115  and the electrical connection unit  110  on the substrate  20 . 
     The test apparatus  100  executes an irradiation step of collectively irradiating the plurality of cells  12  with light (Step S 103 ). As a specific example, the control unit  140  outputs a command to the placement unit  150 , moves the placement unit  150  so that the LED panel  15  is in close contact with the blocking unit  160 , and further outputs a command to the light source unit  120  to irradiate the plurality of cells  12  of the LED panel  15  with the parallel light  122 . Note that, in the present embodiment, all the LEDs  10  included in the plurality of cells  12  of the LED panel  15  are collectively irradiated with the parallel light  122 , but instead of this, some of the LEDs  10  may be sequentially irradiated with the parallel light  10 . 
     The test apparatus  100  executes, for each row of the LED panel  15 , a reading step of reading a photoelectric signal in which light is photoelectrically converted by the LED  10  in each of the two or more cells  12  arranged in the column direction (Step S 105 ). As a specific example, while the light source  121  collectively irradiates the plurality of cells  12  of the LED panel  15  with light by issuing a command to the reading unit  115 , the control unit  140  sequentially reads the photoelectric signal output to each column line  11   c  from each of the plurality of cells  12  arranged in the column direction by setting the row line  11   r  corresponding to the row to be read as a reference voltage and setting the row lines  11   r  corresponding to the rows other than the row to be read as a voltage equal to or lower than the potential of the column line  11   c  for each row. The reference voltage is a positive voltage higher than the potential of the column line  11   c  to which the cell  12  from which the photoelectric signal is to be read is connected, for example, the ground potential. In a case where the column line  11   c  is at the ground potential, the row lines  11   r  corresponding to the rows other than the row to be read may be set to the ground potential or the negative voltage. 
     The test apparatus  100  executes a measurement step of measuring the photoelectric signal read from each of the plurality of cells  12  via the electrical connection unit  110  (Step S 107 ). As a specific example, the control unit  140  issues a command to the measuring unit  130 , causes the current value of the current individually supplied from each column line  11   c  via the electrical connection unit  110  to be measured for each row, and causes the control unit  140  to output the measurement result for each cell  12  including the plurality of LEDs  10 . The control unit  140  stores each measurement result of the plurality of cells  12  in the storage unit  145 . Note that, for each row, the measuring unit  130  may individually measure the current value of the current individually supplied from each column line  11   c  while sequentially switching each column, or may measure the current value in units of cells  12 . In the case of measuring in units of cells  12 , for example, the current values of the currents supplied from three adjacent column lines  11   c  to which three adjacent LEDs  10  emitting respective colors of RGB included in the cell  12  are connected may be collectively measured. 
     The test apparatus  100  executes a determination step of determining the quality of each of the plurality of cells  12  on the basis of the measurement result of the above described measurement step (Step S 109 ), and the flow ends. As a specific example, in a case where the measurement results of all the cells  12  of the LED panel  15  are stored with reference to the measurement results of the storage unit  145  and the reference data, the control unit  140  determines the quality of each of the plurality of cells  12  on the basis of the measurement results. 
     As described above, the control unit  140  in the present embodiment determines at least one cell  12  including at least one LED  10 , among the plurality of cells  12 , in which the measured photoelectric signal is out of the normal range, as defective. The control unit  140  may use, as the normal range, a range based on the statistic corresponding to the photoelectric signal output by each of the plurality of LEDs  10 . As an example of the statistic, a range within the average value ±1σ, a range within the average value ±2σ, or a range within the average value ±3σ of the photoelectric signal may be used. 
     More specifically, the control unit  140  may use different normal ranges for the respective emission colors of the LEDs  10 . The control unit  140  may further use an average current amount and a standard deviation of the photoelectric signals measured for the plurality of concolorous LEDs  10  connected to each other by each column line  11   c.    
     In this case, the control unit  140  calculates the average value and the standard deviation σ on the basis of the current value of the current flowing from the concolorous LEDs  10  for each column line  11   c , which is stored in the storage unit  145 , or on the basis of the current values measured for the plurality of column lines  11   c  to which the concolorous LEDs  10  are connected. In addition, in a case where there are a plurality of peaks in the current values, the statistic of the current values may be calculated using statistical processing capable of corresponding to the plurality of peaks without using the standard deviation. 
     In addition to the statistical processing using the average and the standard deviation, any statistical processing may be used. For example, in order to cope with a case where there are a plurality of peaks or a case where the peaks are biased in the statistical value of the photoelectric signal, a mathematical formula of the standard deviation may be made different, other algorithms or a combination of algorithms may be adopted, and these may be used depending on the characteristics of the LED  10 . An example of another algorithm may be Good Die Bad Neighborhood (GDNB), cluster detection, or the like. 
     Note that, instead of the average current value and the standard deviation described above, the control unit  140  may use the average current amount and the standard deviation of the photoelectric signal measured for each of the plurality of concolorous units obtained by dividing, into two or more LEDs  10 , the plurality of concolorous LEDs  10  connected to each other. 
     The control unit  140  may determine the selected LED  10  as defective in a case where the luminance of the light emitted by the selected LED  10  is out of the normal range. The control unit  140  may use, as the normal range, a range based on a statistic corresponding to the luminance of the light emitted by at least one LED  10  to be subjected to light emission processing. 
     As a comparative example with the test method by the test apparatus  100  of the present embodiment, for example, a test method of optical characteristics of LEDs is conceivable, in which a plurality of LEDs arranged on a wafer are sequentially turned on one by one, and light is received by an image sensor, a spectral luminance meter, or the like to determine whether light is correctly emitted. 
     In a case where the optical characteristics of the plurality of LEDs described above are collectively measured using the test method of the comparative example, light emitted from each of the plurality of adjacent LEDs interferes with each other, a defective LED having a relatively deteriorated optical characteristic cannot be correctly identified, and an image sensor or the like becomes very expensive for performing image recognition in a wide range with high accuracy. In particular, in a case where a plurality of micro LEDs are tested, the problem becomes remarkable. 
     On the other hand, according to the test apparatus  100  of the present embodiment, the electrical connection unit  110  is electrically connected to the LED panel  15 , the plurality of cells  12  included in the LED panel  15  is collectively irradiated with light, and for each row of the LED panel  15 , the photoelectric signal in which the light is photoelectrically converted by the LED  10  in each of the two or more cells  12  arranged in the column direction is read. The test apparatus  100  further measures the photoelectric signal read from each of the plurality of cells  12 , and determines the quality of each of the plurality of cells  12  on the basis of the measurement result. As a result, the test apparatus  100  can not only shorten the processing time by simultaneously measuring the photoelectric signals of the plurality of cells  12 , but also can correctly identify a defective cell  12  having deteriorated optical characteristics by determining the quality of the cell  12  using the measured photoelectric signals without being affected by the measurement of the optical characteristics of the other cells  12 . In addition, according to the test apparatus  100 , the number of cells  12  to be simultaneously measured can be easily expanded. 
     According to the test apparatus  100  of the present embodiment, for the other configurations except for the light source unit  120 , the temperature control unit  126 , the reading unit  115 , the substrate  20 , and the blocking unit  160 , that is, for the electrical connection unit  110 , the measuring unit  130 , the control unit  140 , the storage unit  145 , and the placement unit  150 , those used for testing devices other than optical devices such as the LED panel  15  can be used. 
     Various embodiments of the present invention may also be described with reference to flowcharts and block diagrams, where the blocks may represent (1) a step of processing in which an operation is executed or (2) a section of an apparatus that is responsible for executing the operation. Certain steps and sections may be implemented by dedicated circuitry, programmable circuitry provided with computer-readable instructions stored on a computer-readable medium, and/or a processor provided with computer-readable instructions stored on a computer-readable medium. The dedicated circuitry may include digital and/or analog hardware circuits, and may include integrated circuits (ICs) and/or discrete circuits. The programmable circuitry may include reconfigurable hardware circuits including memory elements such as logic AND, logic OR, logic XOR, logic NAND, logic NOR, and other logic operations, flip-flops, registers, field programmable gate arrays (FPGA), programmable logic arrays (PLA), and the like. 
     The computer-readable medium may include any tangible device capable of storing instructions to be executed by a suitable device, so that the computer-readable medium having the instructions stored therein will have a product including instructions that can be executed to create means for executing the operations specified in flowcharts or block diagrams. Examples of the computer-readable medium may include an electronic storage medium, a magnetic storage medium, an optical storage medium, an electromagnetic storage medium, a semiconductor storage medium, and the like. More specific examples of the computer-readable medium may include a floppy (registered trademark) disk, a diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an electrically erasable programmable read-only memory (EEPROM), a static random access memory (SRAM), a compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a Blu-ray (registered trademark) disk, a memory stick, an integrated circuit card, and the like. 
     The computer-readable instructions may include source code or object code written in any combination of one or more programming languages, including assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state-setting data, or an object oriented programming language such as Smalltalk (registered trademark), JAVA (registered trademark), C++, or the like, and conventional procedural programming languages such as the “C” programming language or similar programming languages. 
     The computer-readable instructions may be provided for a processor or programmable circuitry of a general purpose computer, special purpose computer, or other programmable data processing apparatuses locally or via a wide area network (WAN) such as a local area network (LAN), the Internet, or the like, and execute the computer-readable instructions to create means for executing the operations specified in flowcharts or block diagrams. Examples of the processor include a computer processor, a processing unit, a microprocessor, a digital signal processor, a controller, a microcontroller, and the like. 
       FIG. 5  illustrates an example of a computer  1200  in which a plurality of aspects of the present invention may be fully or partially embodied. A program installed in the computer  1200  can cause the computer  1200  to function as an operation associated with the apparatus according to the embodiment of the present invention or one or more “units” of the apparatus, or execute the operation or the one or more “units”, and/or cause the computer  1200  to execute a process according to the embodiment of the present invention or a step of the processing. Such programs may be executed by a CPU  1212  to cause the computer  1200  to execute certain operations associated with some or all of the blocks in the flowcharts and block diagrams described in the present specification. 
     The computer  1200  according to the present embodiment includes the CPU  1212 , a RAM  1214 , a graphic controller  1216 , and a display device  1218 , which are interconnected by a host controller  1210 . The computer  1200  also includes input/output units such as a communication interface  1222 , a hard disk drive  1224 , a DVD-ROM drive  1226 , and an IC card drive, which are connected to the host controller  1210  via an input/output controller  1220 . The computer also includes legacy input/output units such as a ROM  1230  and a keyboard  1242 , which are connected to the input/output controller  1220  via an input/output chip  1240 . 
     The CPU  1212  operates according to programs stored in the ROM  1230  and the RAM  1214 , thereby controlling each unit. The graphics controller  1216  acquires image data generated by the CPU  1212  in a frame buffer or the like provided in the RAM  1214  or in the graphics controller  1216  itself, such that the image data is displayed on the display device  1218 . 
     The communications interface  1222  communicates with other electronic devices via a network. The hard disk drive  1224  stores programs and data used by the CPU  1212  in the computer  1200 . The DVD-ROM drive  1226  reads program or data from the DVD-ROM  1201  and provides the programs or data to the hard disk drive  1224  via the RAM  1214 . The IC card drive reads programs and data from the IC card and/or writes the programs and data to the IC card. 
     The ROM  1230  stores a boot program and the like, therein, executed by the computer  1200  at the time of activation and/or a program depending on hardware of the computer  1200 . The input/output chip  1240  may also connect various input/output units to the input/output controller  1220  via a parallel port, a serial port, a keyboard port, a mouse port, or the like. 
     The program is provided by a computer-readable storage medium such as a DVD-ROM  1201  or an IC card. The program is read from a computer-readable storage medium, installed in the hard disk drive  1224 , the RAM  1214 , or the ROM  1230  that are also examples of the computer-readable storage medium, and executed by the CPU  1212 . The information processing described in these programs is read by the computer  1200  and provides cooperation between the programs and various types of hardware resources described above. The apparatus or method may be configured by implementing operation or processing of information according to the use of the computer  1200 . 
     For example, in a case where communication is executed between the computer  1200  and an external device, the CPU  1212  may execute a communication program loaded in the RAM  1214  and instruct the communication interface  1222  to execute communication processing on the basis of a process described in the communication program. Under the control of the CPU  1212 , the communication interface  1222  reads transmission data stored in a transmission buffer area provided in a recording medium such as the RAM  1214 , the hard disk drive  1224 , the DVD-ROM  1201 , or the IC card, transmits the read transmission data to the network, or writes reception data received from the network in a reception buffer area or the like provided on the recording medium. 
     In addition, the CPU  1212  may cause the RAM  1214  to read all or a necessary part of a file or database stored in an external recording medium such as the hard disk drive  1224 , the DVD-ROM drive  1226  (DVD-ROM  1201 ), the IC card, or the like, and may execute various types of processing on data on the RAM  1214 . Next, the CPU  1212  may write back the processed data to the external recording medium. 
     Various types of information such as various types of programs, data, tables, and databases may be stored in a recording medium in order to be subjected to information processing. The CPU  1212  may execute various types of processing on the data read from the RAM  1214 , including various types of operations, information processing, conditional determination, conditional branching, unconditional branching, information retrieval/replacement, and the like, which are described throughout the present disclosure and specified by a command sequence of a program, and writes back the results to the RAM  1214 . In addition, the CPU  1212  may retrieve information in a file, a database, or the like in the recording medium. For example, in a case where a plurality of entries each having the attribute value of a first attribute associated with the attribute value of a second attribute is stored in the recording medium, the CPU  1212  may retrieve an entry matching the condition in which the attribute value of the first attribute is specified from among the plurality of entries, read the attribute value of the second attribute stored in the entry, and thereby acquire the attribute value of the second attribute associated with the first attribute satisfying the predetermined condition. 
     The programs or software modules according to the above description may be stored in a computer-readable storage medium on or near the computer  1200 . In addition, a recording medium such as a hard disk or a RAM provided in a server system connected to a dedicated communication network or the Internet can be used as a computer-readable storage medium, thereby providing a program to the computer  1200  via the network. 
     While the embodiments of the present invention have been described, the technical scope of the invention is not limited to the above described embodiments. It is apparent to persons skilled in the art that various alterations and improvements can be added to the above-described embodiments. In addition, the matters described for a specific embodiment can be applied to other embodiments within a scope not technically contradictory. In addition, each component may have a similar feature to other component having the same name and different reference signs. It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the invention. 
     The operations, procedures, steps, and stages of each process performed by an apparatus, system, program, and method shown in the claims, embodiments, or diagrams can be performed in any order as long as the order is not indicated by “prior to,” “before,” or the like and as long as the output from a previous process is not used in a later process. Even if the process flow is described using phrases such as “first” or “next” in the claims, embodiments, or diagrams, it does not necessarily mean that the process must be performed in this order. 
     EXPLANATION OF REFERENCES 
     
         
           10 : LED 
           11 : wiring 
           11   r : row line 
           11   c : column line 
           12 : cell 
           15 : LED panel 
           20 : substrate 
           100 : test apparatus 
           110 : electrical connection unit 
           115 : reading unit 
           116 : row drive unit 
           117 : column drive unit 
           120 : light source unit 
           121 : light source 
           122 : parallel light 
           123 : lens unit 
           124 : filter holding unit 
           125 : temperature suppression filter 
           126 : temperature control unit 
           130 : measuring unit 
           140 : control unit 
           145 : storage unit 
           150 : placement unit 
           160 : blocking unit 
           1200 : computer 
           1201 : DVD-ROM 
           1210 : host controller 
           1212 : CPU 
           1214 : RAM 
           1216 : graphics controller 
           1218 : display device 
           1220 : input/output controller 
           1222 : communication interface 
           1224 : hard disk drive 
           1226 : DVD-ROM drive 
           1230 : ROM 
           1240 : input/output chip 
           1242 : keyboard